Embed Size (px)
Citation preview
BLENDING OF ETHANOL IN GASOLINE FOR SPARK IGNITION ENGINES
PROBLEM INVENTORY
and
EVAPORATIVE MEASUREMENTS
REGISTRERINGSUPPGIFT
Rapport nr MTC 5407 Projektbeteckning
8050407 Utgivningsår/mån 2005-05
Uppdragsgivare: EMFO
ISSN: 1103-0240
Utgivare: AVL MTC Motortestcenter AB Box 223 SE-136 23 Haninge Tel: +46 8 500 656 00 Fax: +46 8 500 283 28 e-post: [email protected]
Författare: Prof. Karl-Erik Egebäck Mr Magnus Henke Mr Björn Rehnlund Mr Mats Wallin (coordinator) Associate Prof. Roger Westerholm
ISRN: ASB-MTC-R—05/2--SE
Rapportens titel Språk:
ENG Engelska: Blending of Ethanol in Gasoline for Spark Ignition Engines – Problem Inventory and Evaporative Measurements. Svenska: Inblandning av Etanol i Bensin för Ottomotorer – Probleminventering och Avdunstningsmätningar.
Antal sidor:
111+ 20
Sammanfattning: Presently all gasoline sold in Sweden contain 5 % of ethanol. Ethanol mixing above 5% is not possible because of the EU-fuel directive as well as The European standard EN 228. However, there is in Sweden an interest in further increasing the bio-ethanol content in gasoline up to at least 10 %. The main reason is that even relatively small percentage additions will result in a substantial total volume of gasoline substitution, and the present infrastructure for distributing fuels can be used largely unchanged. Based on that background the purposes of the study were to collect information on national and international findings and experience related to the use of blends of ethanol in gasoline as fuels in spark ignition engines. The project also included a first study on the impact of the evaporative emissions with different grades of base gasoline and different blending proportions of ethanol. The main conclusion from using ethanol-gasoline blends in practice is that blends with up to 15 percent ethanol will not have any significant negative effects on the wear of the engine or vehicle performance. No significant difference can be seen in regulated emissions when comparing the use of blended fuel (with up to 10-15% ethanol) to the use of neat gasoline. Concerning unregulated emissions views differ. Regarding the emissions of benzene, toluene, ethyl benzene and xylene (BTEX) the main conclusion is that there is a slight decrease when using ethanol blends, while for aldehydes there is a significant increase, especially of acetaldehyde and (to a lesser extent) formaldehyde emissions. However, there is a serious lack of data describing the effects under Swedish conditions. There will be a slight increase (~2-3%) in fuel consumption when shifting from neat gasoline to a 10 percent ethanol-gasoline blend, depending on the design of the vehicle. Cold starts, in particular, will affect fuel consumption more when using blended gasoline than when using neat gasoline. There is a need to generate data and experience by running tests and analysing the environmental effects of blending ethanol with gasoline. The lack of data is more marked for blends with high ethanol contents (~20 %). Such blends should be avoided before a thorough analysis has been carried out and more data are available.
Förslag till nyckelord Engelska: Ethanol, Blending, Gasoline, Exhaust emissions, Regulated, Unregulated, LCA,
Alcohol fuels, Alternative fuels, Evaporative emissions, Vapour pressure, RVP, Svenska: Etanol, Låginblandning, Bensin, Avgasemissioner, Reglerade, Oreglerade, LCA,
Alkoholbränslen, Avdunstningsmätningar, Ångtrycksmätningar, RVP, Hälsoeffekt,
Rapportseriens titel Rapport – MTC AB. www.avlmtc.com
BLENDING OF ETHANOL IN GASOLINE FOR SPARK IGNITION ENGINES
PROBLEM INVENTORY
and
EVAPORATIVE MEASUREMENTS
Study performed by Stockholm University, ATRAX AB, Autoemission KEE Consultant AB, AVL MTC AB.
Financed by Swedish EMFO
2004-2005
Page 2
This study has been carried out by:
Associate Prof. Roger Westerholm Stockholm University [email protected]
Prof. Karl-Erik Egebäck Autoemmission KEE Consultant AB [email protected]
Mr Björn Rehnlund Atrax Energi AB [email protected]
Mr Magnus Henke AVL MTC AB [email protected]
Coordinator: Mr Mats Wallin, Mawalco (representing AVL MTC AB), [email protected]
Contents
0. Summary ...................................................................................................... 4
1. Introduction.................................................................................................. 6
1.1. Background.....................................................................................................6 1.2. Alcohol Blended Fuels ...................................................................................8
2. The Use of Ethanol in Different Countries.............................................. 10
2.1. Prerequisites for the Literature Study...........................................................10 2.2. Fuel Ethanol in Sweden................................................................................10 2.3. Fuel ethanol in the USA/California ..............................................................11 2.4. Fuel Ethanol in Japan ...................................................................................15 2.5. Fuel ethanol in Brazil ...................................................................................15 2.6. Fuel Ethanol in East Asia .............................................................................17 2.7. Fuel Ethanol in Australia..............................................................................19
3. Data and Experience................................................................................. 23
3.1. Vehicle Performance ....................................................................................23 3.2. Cold Starts and Driving ................................................................................25 3.3. Impact of Fuel...............................................................................................25 3.4. Impact of Lube Oil .......................................................................................28 3.5. Impact on Service and Maintenance.............................................................29 3.6. Compatibility and Wear................................................................................30 3.7. Impact of Vapour Lock.................................................................................33
4. Air Quality and Health Effects................................................................. 35
5. Emissions .................................................................................................... 37
5.1. Regulated exhaust emissions ........................................................................37 5.2. Theoretical Discussion about HC Emissions................................................38 5.3. Unregulated Exhaust Emissions ...................................................................38 5.4. Characterisation of Exhaust Emissions ........................................................42
6. Fuel Energy Content – Engine Power...................................................... 45
Page 3
7. Evaluation of Emissions and fuel consumption ...................................... 47
7.1. Evaluation of Emissions in Australia ...........................................................48 7.2. Evaluation of Emissions in Canada ..............................................................52 7.3. Evaluation of Emissions in the UK ..............................................................56 7.4. Evaluation of Emissions in Sweden .............................................................59 7.5. Evaluation of Emissions in the USA ............................................................62 7.6. Fuel Consumption.........................................................................................65
8. Vapour Pressure ........................................................................................ 70
8.1. RVP - USA ...................................................................................................72 8.2. RVP - Brazil .................................................................................................75 8.3. RVP - Europe................................................................................................76 8.4. RVP - Australia ............................................................................................77 8.5. Theoretical Discussion on Vapour Pressure Using Raoult’s Law................77 8.6. Findings ........................................................................................................78
9. Risk for Explosions at Low Ambient Temperatures.............................. 79
10. Life Cycle Analysis (LCA) of Gasoline and Ethanol Blends ................. 80
10.1. LCA in the Context of This Project..............................................................80 10.2. LCA Studies for Ethanol in Neat Form or Blended with Gasoline ..............81 10.3. Discussion.....................................................................................................83 10.4. Findings ........................................................................................................84
11. Conclusions and Recommendations ........................................................ 85
11.1. Fuel Reid Vapour Pressure ...........................................................................86 11.2. Regulated Emissions.....................................................................................87 11.3. Unregulated Emissions .................................................................................88 11.4. Performance and Wear .................................................................................88 11.5. Life Cycle Analysis ......................................................................................89
12. References................................................................................................... 90
13. Abbreviations ...........................................................................................103
14. Appendix 1................................................................................................105
14.1. Emission tests in Canada ............................................................................105 14.2. Emission tests in UK ..................................................................................106
15. Appendix 2................................................................................................111
15.1. Evaporation Test of Two Ethanol Blended RON 95 Summer Gasolines...111
Page 4
0. SUMMARY The purpose of the study reported here was to collect information on national and international findings and experience related to the use of blends of ethanol in gasoline as fuels in spark ignition engines. The main reason for blending ethanol with gasoline is to reduce fossil carbon dioxide emissions (and thus the greenhouse effect) from vehicles by using bio-ethanol originating from renewable sources. Presently all gasoline sold in Sweden contain 5 % of ethanol (here and throughout the text such percentages refer to the alcohol content of blends by volume) and the relevant authorities are interested in further increasing the bio-ethanol content in gasoline. Blending bio fuels with a petroleum-based fuel has the twin advantages that even relatively small percentage additions will result in a substantial total volume of gasoline substitution, and the present infrastructure for distributing fuels can be used largely unchanged.
Another aim of the project was to study the impact of using such blends on evaporative emissions by carrying out measurements with different grades of base gasoline and different blending proportions of ethanol. A report on these measurements can be found in the appendix to this report.
The results and experience presented in this report originate from Sweden, the USA, Japan, Brazil, China, India, Thailand and Australia. The main topics discussed are the effects of using blends on: vehicle performance, cold starts and drivability, fuel and lubricating oil performance, service and maintenance, compatibility and wear, vapour lock, emissions (regulated and unregulated), fuel consumption, fuel energy content, Reid Vapour Pressure (RVP) and Life Cycle Analyses. The main conclusions of the study are as follows:
• There is intense interest world-wide in using ethanol as an automotive fuel, especially in blending ethanol with gasoline. Blending ethanol in a commonly used fossil fuel is generally seen as an easy way to introduce an alternative such as bio-ethanol without costly changes of the fleet of vehicles on the road.
• Ethanol can easily be blended in gasoline by well known methods. Ethanol has a lower heating value than gasoline, which will reduce the energy content of the fuel. However this can be partly offset by the higher octane value of ethanol.
• The main conclusion from using ethanol-gasoline blends in practice is that blends with up to 15 percent ethanol will not have any significant negative effects on the wear of the engine or vehicle performance.
• No significant difference can be seen in regulated emissions when comparing the use of blended fuel (with up to 10-15% ethanol) to the use of neat gasoline. Concerning unregulated emissions views differ. Regarding the emissions of benzene, toluene, ethyl benzene and xylene (BTEX) the main conclusion is that there is a slight decrease when using ethanol blends, while for aldehydes there is a significant increase, especially of acetaldehyde and (to a lesser extent) formaldehyde emissions. However, there is a serious lack of data describing the effects under Swedish conditions.
• There will be a slight increase (~2-3%) in fuel consumption when shifting from neat gasoline to a 10 percent ethanol-gasoline blend, depending on the design of the vehicle. Cold starts, in particular, will affect fuel consumption more when using blended gasoline than when using neat gasoline.
Page 5
There is a need to generate data and experience by running tests and analysing the environmental effects of blending ethanol with gasoline. The lack of data is even more marked for blends with high ethanol contents (~20 %). Such blends should be avoided before a thorough analysis has been carried out and more data are available.
In the light of the situation and conditions in Sweden and the other countries belonging to the European Union there are certain barriers to overcome in order to succeed with the intention to increase the content of ethanol in blended gasoline. In addition, given the differences in conditions and regulations between Sweden, other countries belonging to the European Union, and regions where there is long experience of running vehicles on blended fuels, a number of issues have to be addressed before the alcohol content of blends is increased.
A first issue to address is the problem that the RVP increases when ethanol is blended with gasoline since current gasoline standards impose limits on its RVP. Therefore, either there must be an exemption for ethanol blended fuels or the base gasoline RVP must be adjusted. Such adjustments are already made today to the base gasoline used in the 5 % ethanol gasoline blends.
A second issue is concern about the performance and start-ability of vehicles at low temperatures, which commonly occur in wintertime, especially in the northern parts of Sweden.
A third issue is whether blends with 10 to 15 percent ethanol in gasoline will affect human health and the environment (both local and regional).
The report includes 181 references and was financed by the Swedish Emission Research Program (Emissionsforskningsprogrammet, EMFO).
Page 6
1. INTRODUCTION
1.1. Background
A challenge that humanity must take seriously is to limit and decrease the greenhouse effect caused by various human activities.
A major contributor to the greenhouse effect is the transport sector* due to the heavy, and increasing, traffic levels. In spite of ongoing activity to promote efficiency, the sector is still generating significant increases in CO2 emissions. As transport levels are expected to rise substantially, especially in developing countries, fairly drastic political decisions may have to be taken to address this problem in the future. Furthermore, the dwindling supply of petroleum fuels will sooner or later become a limiting factor.
An important step in efforts to solve the problem is to replace fossil source energy with bioenergy. In the transport sector this means either introducing bio fuels and using adapted vehicles, or blending bio fuels with petroleum-based fuels for use with present vehicle fleets. The two alternatives are not, of course, mutually exclusive. However, blending bio fuels with petroleum-based fuels for use by the present conventional vehicle fleets has the advantages that even using quite low blending concentrations will result in substantial total volumes of gasoline being substituted by bio fuels, and that the present infrastructure for distributing fuels can be used.
Today, the transport sector is a major contributor to net emissions of greenhouse gases, of which carbon dioxide is particularly important. In Sweden this sector accounts for roughly 20 % of total energy consumption, and almost 50 % of the total net emissions of carbon dioxide. The carbon dioxide emissions originate mainly from the use of fossil fuels, mostly gasoline and diesel oil in road transportation systems, although some originates from other types of fossil fuels such as natural gas and Liquefied Petroleum Gas (LPG).
If international and national goals (such as those set out in the Kyoto protocol) for reducing net emissions of carbon dioxide are to be met, the use of fossil fuels in the transport sector has to be substantially reduced. This can be done, to some extent, by increasing the energy efficiency of engines and vehicles and thus reducing fuel consumption on a volume per unit distance travelled basis. However, since the total transportation work load is steadily increasing such measures will not be sufficient if we really want to reduce the emissions of carbon dioxide. In order to reduce absolute amounts of these emissions we have to go further and an additional measure that will be required is to replace fossil vehicle fuels with renewable ones. Primarily, especially in the short term, this means bio-based fuels.
Probably the best candidate bio fuels to replace gasoline in the short term are alcohols. Alcohols can be blended with gasoline or used as neat fuel in both optimised spark ignition engines and compression ignition engines. In the medium term ethanol produced from grain will probably be
* Approx 30% according to the Annual Report of Greenhouse Gas Emissions from the Swedish EPA, 2002
Page 7
the most important alternative fuel for replacing gasoline, and in the long term ethanol produced from cellulose might take over from grain ethanol.
Today, ethanol accounts for a substantial part of the alternative fuel market, especially in Brazil, the USA and Sweden. The advantages of ethanol are that it can:
• Provide a viable alternative to reduce the greenhouse effect. • Be produced domestically, thereby reducing dependence on imported petroleum. • Be easily mixed with gasoline. • Be used (and already is on a wide scale) as an oxygenate in gasoline. • Create new jobs in the country related to its production.’
From an international perspective, most research up to 1990 was focused on blends of methanol and gasoline, but some studies were carried out on ethanol-gasoline blends. Since these studies were carried out in the USA, it can be assumed that they mainly included vehicles with efficient emission control systems, but at the same time technical features of cars in the USA have historically differed, at least in part, from those in Sweden. It should also be noted that for a long time 10% ethanol has been added to commercial gasoline in many parts of the USA. In the USA there is considerable experience of adding higher proportions of ethanol to gasoline than those allowed by gasoline regulations in Sweden (Europe). The primary advantage of adding a bio-based alcohol to gasoline is that it reduces net CO2 emissions but it also has other positive effects, such as increasing the octane value of the fuel and reducing the benzene content of the exhaust gases.
The use of alcohol blended gasoline and neat fuel alcohols as substitutes for neat gasoline have become matters of interest in many countries. The International Energy Agency (IEA), established in 1974, follows the development, and data and other experience from various trials have been presented and discussed at symposia organised by the International Symposium on Alcohol Fuels (ISAF). The first ISAF-symposium was organized in Stockholm 1978 and since then a symposium has been organized every 2 to 4 years.
Today, almost all the alcohol fuel used is ethanol and it has three main uses in Sweden: as neat ethanol in ca 400 buses; in a gasoline blend (E85) for Flexible Fuelled Vehicles (FFVs), of which approximately 17 000 were being used in Sweden in February 2005; and as a component of all of the other gasoline (E5) used throughout the country. This means that the most common alternative fuel used in Sweden is ethanol. Only approximately 65 000 m3 (50 000 m3 from wheat and 15 000 from cellulose) of this alcohol is domestically produced and at the time of writing around 165 000 m3 is imported from Brazil. The goal for the future is to increase the amount of domestically-produced ethanol from cellulose (ligno-cellulose) and one step toward this goal is research to be carried out at a pilot plant.
The goals of the project presented in this report are to accumulate the data required to facilitate increased use of bio fuel by:
• Studying available literature, collected knowledge, identified data as well as yet undocumented experience concerning emissions when using ethanol blended gasoline.
• Evaluating the relevance of existing investigations and the data generated in them. • Assessing what (if any) emission studies are needed to estimate reliably the effects of
using ethanol blended gasoline on total emissions, both qualitative and quantitative. • Measuring evaporative emissions from the combustion of different blends of ethanol and
neat gasoline.
Page 8
1.2. Alcohol Blended Fuels
The idea of adding low contents of ethanol or methanol to gasoline is not new, extending back at least to the 1970s, when oil supplies were reduced and a search for alternative energy carriers began in order to replace gasoline and diesel fuel. Initially, methanol was considered the most attractive alcohol to be added to gasoline. Since methanol can be produced from natural gas at no great cost, and is quite easy to blend with gasoline, this alcohol was seen as an attractive additive. However, when using methanol in practice it became clear that precautions had to be taken when handling it and that methanol is aggressive to some materials, such as plastic components and even metals in the fuel system. A lesson learned was that new, more resistant materials had to be used in the fuel system of the vehicles as well as in the distribution system. These experiences were also of great value when ethanol came to be more commonly used as an alternative to the commercial fuels, since even ethanol can be characterized as an aggressive fluid, albeit somewhat less so than methanol. The interest in producing an alternative fuel based on biomass has also been a major factor in the early choice between methanol and ethanol.
The use of E85, a mixture of 85 % ethanol and 15 % gasoline, for FFVs has become common. Blends with other percentages of ethanol in gasoline are commonly used in various countries around the world, especially Australia (officially 10 %), Brazil (up to 25 %), Canada (10 %), Sweden (5 %) and the USA (up to 10 %). There is still debate about whether, how and to what extent ethanol in gasoline may affect the materials in the vehicle and cause excessive wear of parts in the fuel system and the engine. However, in the USA, car manufacturers have agreed that use of gasoline with up to 10 % ethanol will not affect the warranties of their vehicles (Science Fair Projects Encyclopaedia, 2004; Launder, 2001). In his MSc thesis Launder described the development of the use of fuel alcohol, especially the use of ethanol in the USA. Amongst other salient facts noted by Launder “Minnesota has also passed legislation requiring the use of 10% ethanol in all gasoline”.
Since both methanol and ethanol have considerably lower energy contents (15.7 MJ/l and 21.4 MJ/l, respectively) compared with gasoline (approximately 35 MJ/l) use of an alcohol-containing blend may affect the power output of the engine to varying degrees, depending on its design. In section 6 the calculated effects on the energy content of the fuel of blending ethanol with a specific gasoline are presented. According to these calculations, adding ethanol to a final volume of 10 % to a gasoline with an energy content of 32.3 MJ/litre will decrease that value by 3.4 %.
Blending alcohol in gasoline will affect, inter alia, the vapour pressure of the fuel and, as shown in section 8, the increase in vapour pressure is considerably larger when blending methanol than when blending ethanol. The alcohol is commonly added to gasoline when filling the tank of the vehicle that will deliver the fuel to the gas stations. More sophisticated blending technologies such as Ratio Blending, Sidestream Blending and Wildstream Blending are described and discussed in a paper by Toptech (2004). Of these “Ratio Blending” is designed for use when up to six components are to be blended. “Sequential Blending” of ethanol in gasoline means that the two components are pumped to the delivery truck in sequence. Even if it is computer controlled there are some uncertainties about whether the resulting mixtures will fulfil their specifications. “Sidestream Blending” is similar to ratio blending and is used when two or more components are to be mixed together and “Wildstream Blending” can be used when blending ethanol with gasolines of many different qualities simultaneously. In Figure 1.1 the configuration of Sidestream Blending is shown.
Page 9
Figure 1.1. Configuration of “Sidestream Blending”
Since there are concerns related to the fact that ethanol is readily miscible with water it is important to use water-free systems when blending ethanol in gasoline. It is, of course, also important to use cost-efficient methods.
At least five major reasons for blending ethanol in gasoline are discussed, including the following advantages of using ethanol as an alternative fuel:
1. Reduction of net carbon dioxide emissions, to mitigate global warming.
2. The need to replace petroleum fuels with a renewable fuel
3. The need (especially in the US) to improve the air quality in non-attainment areas, i.e. areas of the country where air pollution levels persistently exceed the national ambient air quality standards.
4. The need to reduce the dependence on imported fuels.
5. To create new jobs in the country by national production of ethanol.
In Table 1.1 selected fuel properties for a neat gasoline and ethanol blends with the neat gasoline are shown. Density, RON and MON numbers and the IBP (initial boiling point) of the blended fuels increase as ethanol contents increase, while 10 %, 90 % and FBP (final boiling point) decrease. Using the blended fuels reduces brake specific energy consumption.
Table 1.1, Fuel properties of ethanol gasoline fuel blends (He et al., 2003) Fuel parameters Neat gasoline E10 (10 % ethanol) E30 (30 % ethanol) Density at 19°C 0.736 0.741 0.751 RON 92.4 95.0 99.7 MON 81.2 82.3 86.6 IBP 36.0 37.5 40.0 10% 55.2 49.0 52.7 50% 92.5 73.2 72.5 90% 153.7 149.8 145.7 FBP 184.5 181.0 181.5
Page 10
2. THE USE OF ETHANOL IN DIFFERENT COUNTRIES
2.1. Prerequisites for the Literature Study
When the parameters of the literature survey for this project were considered it soon became apparent that the foci should be on the influence of adding ethanol on the vehicle and emissions (and thus its effects on the environment, air quality and health). Consequently, it was concluded that the following subjects should be examined during the search and discussed in the report:
• Vehicle performance/wear. • Fuel. • Vapour pressure. • Emissions. • Air quality and health effects. • Life cycle analyses.
2.2. Fuel Ethanol in Sweden
Two sets of standards for fuel ethanol are presented here, one of which was developed by a small quantity ethanol producer in Sweden and one by the American Society for Testing and Materials (ASTM) as an industry standard.
The Swedish producer of ethanol, Svensk Etanolkemi AB (SEKAB) has presented specifications for fuel ethanol to be used when blending ethanol with gasoline, see Table 2.1 (SEKAB, 2004). The oil crises of 1973 and 1976 prompted a search in Sweden for alternatives to gasoline for light duty vehicles and a project was initiated to study the possibility of replacing some gasoline with an alcohol. Since a governmental investigation had been launched in 1965 in order to study an introduction of emission regulations it was also seen as the use of an alcohol blended gasoline could be one measure to reduce especially the emission of CO
To address practical issues associated with introducing an alcohol-based fuel a wide-ranging study was organized by the Swedish National Board for Technical Development (STU). Initially, this work was carried out by a small company named the Swedish Methanol Company, since it concentrated on the use of methanol as an additive to gasoline. Later, ethanol and other potential alternatives were included in the project and Sweden also became a member of the International Energy Agency (IEA). The company carrying out the work was then renamed the Swedish Motor Fuel Technology Co. (SDAB).
The work within the project included both laboratory and field tests. The results of laboratory investigations and field trials that had been carried out in various locations around the world were reported to the IEA in 1986 by STU and SDAB. (STU, 1986;1987). The countries that helped prepare the report were Canada, Japan New Zealand, Sweden and the USA. A great deal of valuable experience concerning the use of alcohol and (especially) alcohol blended gasoline was gathered during this co-operative assessment of alternative fuels. However, at this time Brazil was the only country in the world that was focusing on ethanol as an alternative to gasoline.
Page 11
Table 2.1. Sales specification of technical ethanol 99.5% SPSE-Ethanol 99.5% 3 4 1 (1) 2004-11-03 SPSE-410. Parameter Limit Method of analysis Ethanol % by volume
% by weight min 99.8 min 99.7
ASME 1112
Density (D 20/4) g/ml max 0.790 SS-ISO 758 Appearance Clear, without particles ASTM D 2090 Colour Hazel max 5 AMSE 1102 Water % by weight max 0.3 SS-ISO 760 Aldehydes (as acetaldehyde) % by weight max 0.0025 AMSE 1118 Acidity (as acetic acid) % by weight max 0.0025 AMSE 1114 Fusel oil mg/l max 50 AMSE 1107, GC-
method Methanol mg/l max 20 AMSE 1107, GC-
method Distillation interval*: - starting point - drypoint
°C °C
min 77 max 81
ASTM D 1078
Flashpoint* °C +12 SS-EN 22719 Explosion limits* % by volume in air 3.5 - 15 Accepted from
literature Refractive index* nD20 1.3618 Accepted from
Literature Evaporation residue* mg/l max 10 AMSE 1124 *The seller guarantees these properties, although they are not tested on each delivery.
During the 1980s the focus of investigations and trials with alcohol fuels in Sweden switched to ethanol, both as an alternative for diesel oil and as an additive to gasoline. At this time the main rationale for introducing an alternative was to reduce exhaust emissions. Since the introduction of emission control systems with catalysts for gasoline-fuelled vehicles had efficiently reduced exhaust emissions, most of the research on alternative fuels in Sweden during the 1980s and 1990s was related to diesel-fuelled vehicles. Several comparative reports on different fuels, including alcohol-gasoline blends, were prepared, and the most comprehensive investigations are summarised and discussed in the following text.
In Sweden ethanol is currently used in the following three forms:
1. Blended in gasoline to a volume of 5 % according to the Swedish Petroleum Institute (SPI). 2. E85 in Flexible fuelled vehicles (FFVs). 3. E100 (including an ignition improver and other additives) for use in ethanol-fuelled buses.
2.3. Fuel ethanol in the USA/California
In the year 2000 the projected consumption of gasoline in the US was 127.568 milliard US gallons (468.897 million m3), of which E10 accounted for 908.700 million gallons (ca 3.440 million m3) and the consumption of MTBE in gasoline amounted to 2.1115 milliard gallons (ca 11.780 million m3) according to the US department of energy (Yacobucci and Womach, 2000), see also Table 2.2. Since MTBE blending will be out by the end of 2005 according to MathPro (2002) there will be a need to increase the use of ethanol blended gasoline. According to
Page 12
MathPro “The mandate volume would increase on an annual schedule, reaching 5 billion gallons per year (bgy) in 2012” of ethanol. Thereafter, annual mandate volumes would be set to maintain the percentage share of the U.S. gasoline pool that ethanol held in 2012”. Table 2.2 Estimated US Consumption of Fuel Ethanol, MTBE and Gasoline (Thousand Gasoline Equivalent Gallons), (Department of Energy,1998).
1994 1996 1998 2000 (projected)
E85 80 694 1,727 3,283
E95 140 2 699 59a 59
Ethanol in Gasohol (E10) 845 900 660 200 916 000 908 700
MTBE in Gasoline 2 108 800 2 749 700 2 915 600 3 111 500
Gasolineb 113 144 000 117 783 000 122 849 000 127 568 000 The US Renewable Fuels Association (RFA) has presented industry guidelines for the use of ethanol in the American market and according to the Association the guidelines represent “a compilation of the key technical aspects of fuel grade ethanol use based on the collective experience and expertise of our member companies” (Renewable Fuels Association, 2002). The following industry standard is valid as the industry standard for fuel ethanol to be blended in gasoline to any rate in the USA, Table 2.3. Table 2.3. Industry standard for fuel ethanol to be blended in gasoline in the US.
ASTM 4806 Property Specification ASTM Test
Method Ethanol, vol% 92.1 D5501 Methanol, vol% 0.5 Solvent-washed gum, mg/100 ml max 5.0 D381 Water content, vol%, max 1.0 E203 Denaturant content, vol%, min 1.96 Denaturant content, vol%, max 4.76 Inorganic chloride content, mass ppm (mg/L), max 40 (32) D512 Copper content mg/kg, max 0.1 D1688 Acidity (as acetic acid, mass-% (mg/L), max 0.007 (56) D1613 pH 6.5 – 9.0 D6423 Appearance Visibly free of suspended or
precipitated contaminants (clear & bright)
In the cited report the RFA gave certain recommendations and discussed a number of effects linked to the use of ethanol blended gasoline. The producers of ethanol and member companies of the RFA were recommended “to add corrosion inhibitors to all of their fuel grade ethanol at a treat rate to provide corrosion protection” comparable to the treatments applied to fuels such as neat gasoline
Page 13
According to the RFA adding ethanol will affect several properties of gasoline, including its octane number, volatility, water solubility and oxygen content (the oxygen content of ethanol is approximately 33 % by weight). The octane numbers of ethanol quoted in various reports and other data sources differ, but in the cited paper from RFA (Renewable Fuels Association, 2002) the blending research octane number (RON) of ethanol is 129.0 and the blending motor octane number (MON) 96.0. Chevron has also reported that ethanol has a “Blending Research Octane Number (BRON)” of 129 (Chevron, 2002-2005).
An issue that should be addressed is whether (and if so, to what degree) the octane numbers will increase when blending ethanol in gasoline, and here too opinions differ. In the paper from RFA it is stated that the octane numbers (R+M)/2 will increase by 2 to 3 units. Since fuel ethanol has a higher octane number than gasoline it may well be true that adding ethanol to gasoline increases the octane number, and thus improves the performance of the vehicle. However, there is considerable uncertainty about the extent to which the engine power will improve and whether this improvement will occur across the whole range of ethanol contents in gasoline. During an experimental investigation of ethanol blends in gasoline Abel-Rahman and Osman found that the maximum engine indicated power improvement occurred with a 10 % ethanol blend when adapting the compression ratio of the engine to the fuel Abel-Rahman and Osman, (1997). Performance tests were carried out when using different percentages up to 40 % of ethanol in gasoline.
Maintaining the safety of the working environment is an important issue when working with automotive fuels. In its Industry Guidelines, Specifications, and Procedures, the RFA recommends that ethanol should be handled “with the same safety precautions as gasoline” and that sparks and flames should be avoided when handling ethanol. A further recommendation is to “wear safety goggles when handling ethanol” Renewable Fuels Association, (2002). In addition, a guidebook released by the US Department of Energy (DOE) recommends that skin and vapour contact with E85 should be avoided and that ethanol-resistant gloves should be used (US Department of Energy, 2001). Further valuable information on many aspects of using alcohols in gasoline can be found in literature from the USA/California, where experience in their use (especially ethanol) and test data (both laboratory and field based) have been gathered over a long time. Unfortunately, however, few reports on measurements of emissions obtained when using ethanol blended gasoline have been found.
Progress towards the use of alcohol-gasoline blends as fuels has been underway since at least the 1970s, according to a report by Launder (2001). The Arab countries’ embargo in the 1970s against the USA was the main factor that initially prompted use of alcohol fuels (ethanol and methanol) as substitutes to compensate for the resulting drop in gasoline supplies. An Energy Tax Act was passed, exempting 10 % ethanol-gasoline blends from the 4% gallon tax on motor fuels applied at the time. In the 1980s three additional Acts were passed that promoted production of ethanol from corn, inter alia, and these measures were reinforced by a “blender’s credit” of 40 cents per gallon. It should be noted that the big automobile manufacturers Chrysler, Ford and GM were in favour of the E10 (gasohol) and they stated that its use would be covered in their vehicle guarantees, a move that was subsequently followed by almost all manufacturers.
Since the environmental protection authorities also favour the use of ethanol blended gasoline it has became common in US to blend 10 % ethanol in commercial gasoline. The Clean Air Act of 1990 mandated the use of reformulated gasoline (RFG) in certain areas of the USA to ameliorate air quality problems, such as high ozone levels, and the use of oxygen blended fuel in areas with high levels of carbon monoxide during the winter. In order to meet the demand for ethanol as a
Page 14
blending component a 1-psi waiver in the permitted vapour pressure parameter (RVP) has been allowed for ethanol-gasoline blends, although it has been shown that ethanol will raise the vapour pressure of the fuel. An increase in vapour pressure has been shown to increase the emissions of VOCs (volatile organic components), which may in worst case scenarios result in enhanced levels of ozone (US EPA, 1993). Therefore, the EPA has argued that no waiver should be applied, as can be seen in the following quotation: “EPA believes that ethanol can and will play an important role in reformulated gasoline without a 1.0 psi waiver, and that granting such a waiver would therefore be unreasonable” (US EPA, 1993).
At the end of 2001 “A bill to amend the Clean Air Act to address problems concerning methyl tertiary butyl ether, and for other purposes” was introduced to the US Senate concerning reformulated fuel. In a summary of the bill the following seven amendments (abbreviated here) were recommended to the Senate:
• Actions should be taken concerning the leakage of MTBE from corrodible underground tanks, which represents a risk for public health, welfare and the environment and inspections of underground tanks should be carried out.
• The Clean Air Act should authorize any State “for which a waiver is in effect to impose control of any fuels and fuel additive for the purpose of water quality protection. Requires the Administrator of the Environmental Protection Agency to ban the use of MTBE in motor fuel within four years of this Act´s enactment”.
• The State Governor should be authorized, “upon notification” of the EPA Administrator, “to waive oxygen content requirements for reformulated gasoline other than those regarding oxygen content to be reformulated gasoline”. This “Requires regulations to: (1) ensure that toxic air pollutant emissions reductions achieved under the reformulated gasoline program are maintained in such States; and (2) establish performance standards”.
• The amendments require the Administrator to: (1) carry out tests in order to evaluate health and environmental effects of the use of fuel and fuel additives. Furthermore, tests should be carried out in order to study the effects of using MTBE and other ethers which may be used to replace MTBE; (2) to publish analysis showing changes of the air quality resulting from implementation of the Act; (3) to complete a model which reflects the effects on the emissions that are related to the characteristics or components of the fuel used during 2005.
• The Act eliminates the waiver that allows higher RVP limits for ethanol blended gasoline.
• “Allows State implementation plan revisions that apply conventional gasoline prohibitions to non classified areas”.
• The Act also authorizes “grants to MTBE merchant producers to assist in conversion of production facilities to the production of other fuel additives. Authorizes appropriations” (US Senate 2001).
2.4. Fuel Ethanol in Japan
It has been difficult to find information on investigations carried out in Japan concerning the introduction and use of ethanol in either neat or blended forms. One reason for this is that interest in ethanol has been low in Japan. Another is that the few relevant reports that have been found have nearly all been written in Japanese.
Page 15
However, Japanese interest in alternative fuels has been concentrated for many years on natural gas or liquid fuels that could be produced from natural gas, such as methanol and DiMethyl Ether (DME). In recent years Japan has also shown increasing interest in so-called synthetic fuels, such as paraffin (synthetic diesel) and (to some extent) alkylate (synthetic gasoline) fuels produced from natural gas (and maybe in the future from gasified biomass) by the so-called Fischer-Tropsch technique.
In the last few decades methanol has been the main Japanese alternative to gasoline. However, according to some unconfirmed reports and personal communication with Jan Lindstedt, The Swedish Bioalkohol fuels Foundation, BAFF, Japan has started to introduce ethanol and is currently planning to increase its use.
2.5. Fuel ethanol in Brazil
In a paper released by the Brazilian embassy in India information about the national program for fuel alcohol in Brazil (PROALCOOL) can be found (Brazilian Embassy, 2002). According to this paper, the program that initially introduced the use of ethanol as an automotive fuel in Brazil started in 1974 “as a consequence of the oil crisis”. Sugar cane plantations introduced by the Portuguese in the 16th century were, and still are, used as sources for the ethanol production.
One of the main requirements linked to the introduction of PROALCOOL was that there should be close coordination amongst the authorities and other parties involved, namely “the Ministry of Agriculture and sugarcane planters, the Ministry of Science and Technology and research centres, the Ministry of Industry and Commerce, the automobile industry, Ministry of Mines and Energy, PETROBRÁS (state owned oil company), the fuel distributors, and the gas stations, the Ministries of Finance and Planning and, last but not the least, the automobile owners”. There was also a requirement that subsidies should be used to stimulate the production of cars to be run on alcohol, and the relaxation of tax on industrialised products is seen to have been effective in this context.
An important benefit of the program is that it has provided stable employment for approximately 500 000 workers in the sugar cane plantations and similar numbers in the alcohol/ethanol production industry and other activities connected to the use of ethanol fuels such as transportation, blending etc.
There have also been considerable benefits in terms of greenhouse gas reductions since ethanol produced in Brazil is exported to and used in many countries, especially India, Japan, China, Thailand and Australia. A certain amount is also exported to Sweden and blended in gasoline.
Page 16
. Figure 2.1. Growth in ethanol production (anhydrous and hydrous) in Brazil from 1975/76 to 2003/4.
In a workshop on Mitigation (SBSTA 21/COP in December 2004 in Buenos Aires Alfred Szwarc (a consultant at the Ministry of Science and Technology) described Brazilian experience with fuel grade ethanol. He noted that two types of ethanol fuels - anhydrous (min. ethanol content 99.58 %) and hydrous (ethanol content 95.13 – 95.98 %) - are produced under Brazilian regulations. Anhydrous ethanol can be blended with gasoline up to 25 % by volume while hydrous ethanol is used either as a neat fuel or blended with gasohol (see section 13 for the definition of gasohol) for use in FFVs (Szwarc, 2004).
Unfortunately, few papers prepared in Brazil and written in English have been found. Therefore, the effects that ethanol-gasoline blends with up to 25 % ethanol contents have had on the drivability, deterioration and wear of vehicles and last (but not least) the emissions and air quality in urban areas are not clear.
According to Szwarc, the use of ethanol as a blending component has increased over the years and the content of ethanol in Brazilian gasoline blends has increased from 4.5 % by volume in 1977 to 25 % in 2002, as shown in Figure 2.2. However, today more than 4.2 million cars are ethanol-powered according to data and information presented by Online TEFL. Of these, about 40 % are passenger cars and in total the 4.2 million vehicles annually consume approximately 14 million m3
of ethanol (Ethanol Curriculum Online TEFL Module 5, 2005).
Page 17
%
0
5
10
15
20
25
30
1977 1979 1981 1985 1998 1999 2002
BRAZIL: MAX PRECENT ETHANOL IN GASOLINE OVER TIME
YEAR Figure 2.2. Changes in the maximum ethanol content of ethanol-gasoline blends in Brazil, 1977-2002 (Szwarc, 2004).
No actual data from emission tests in Brazil have been found, but the following observations were made by Szwarc (2004) at the workshop in Buenos Aires.
“Vehicle Emission Reductions Related to Fuel Ethanol Use in Brazil: • Lead additives banned since 1990. • Reduction of SOx. • Reduction of PM (carbon and sulfate particles). • VOC´s with lower toxicity & photochemical reactivity. • CO: Higher reduction in older E100 (up to 70%) and gasohol (up to 40%) vehicles in
comparison with ethanol-free gasoline”.
2.6. Fuel Ethanol in East Asia
In addition to Japan several other countries in East Asia, including China, India and Thailand, are investigating the effects of using ethanol blended gasoline on the environment, vehicles and other issues. These countries have good opportunities to start ethanol production on varying scales.
China In 2001 the Chinese State Development Commission launched an ethanol program and after careful consideration issued quality standards for denatured ethanol and ethanol blended gasoline. In the same year Beijing (China) also organised a World fuel ethanol congress (2001).
It is well known that there is an urgent need to improve the air quality in China, especially in Beijing, and when it launched the program the Chinese government announced that “China plans to spend nearly $12 billion on a program to cut smog and pollution in Beijing by 2008. This emphasises one of the reasons for the large-scale introduction of ethanol, and when launching the program it was also said that “China may soon become an ethanol industry leader...” The program for the Congress also indicates that this event was considered a platform for initiating use of ethanol as an automotive fuel on a broader scale (Beijing World Fuel Ethanol Congress 2001).
Page 18
In China ethanol is commonly produced from corn and sorghum (Nan et al., 1994). According to the Beijing Times, China is “pushing” the use of ethanol as fuel by constructing a plant in the Henan province that will produce 300 000 tons of fuel per year (Beijing Times, 2002). A headline in the Beijing Times also stated that “China Promotes Ethanol-Based Fuel in Five Cities”. Otherwise, this should be changed to ‘The Beijing Times has also reported that China is promoting the use of ethanol-based fuel in five cities”. These five cities are Zhengzhou, Luoyang and Nanyang in Henan province and Harbin and Zhaodong in Heilongjiang province, northeast China (Beijing Times, 2002a). In order to force motorists to use fuel ethanol, all vehicles carrying a licence plate starting with “Yu A” have to use ethanol-based fuel according to an order by the Zhengzhou Municipal Government. The specification of “ethanol-based fuel” is not clear, but in another paper it is said that ethanol will be blended with lead-free gasoline in a 1:9 ratio (US Commercial Service, 2003). In the province of Liaoning new regulations state that car owners must use ethanol as a fuel for their vehicles. If they do not switch to ethanol they will be fined between 5,000 yuan (US$600) and 30,000 yuan (US$3,600) since "Ethanol fuel can play an important role in easing consumption of traditional petrol and protecting the environment" according to the Liaoning Development and Reform Committee (People’s Daily, 2004).
India In India, like other countries around the world, there was a considerable shortage of oil and sharp rises in crude oil prices in the 1970s, prompting interest in fuel ethanol. In India too, plans have been developed to use ethanol-gasoline blends (Uppal, 2002; Bhanot and Chaudhari, 2003), and even ethanol-diesel oil blends (Acharya et al., 2002).
Based on recommendations by a committee for the development of alternative fuels for motor vehicles, trials were carried out in New Delhi in 1991. The test fleet included 93 vehicles and comprised cars, vans and jeeps. The fuels used were blends of 5 % and 10 % ethanol in gasoline. The results of the field trials are summarised in the following quotation:
• “93 Delhi Admn. vehicles logged 1.787 milj km. • Saving of around 20 m3 of scarce gasoline. • Cooler and smoother operation of vehicles. • No adverse effect on engine oil. • Reduction in CO and HC emissions. • Overall fuel economy is comparable with neat gasoline operation” (Malhotra, 2001).
There seems to have been a lull in the development of fuel ethanol in India during the 1990s. However, according to the available literature considerable activity is now underway.
Since the authorities in India found that the agriculture sector needed support and that air quality had to be improved the Ministry of Petroleum and Natural Gas Resolution started to examine issues related to the introduction of ethanol blended gasoline. According to the specifications set by the Bureau of Indian Standards for Gasoline up to 5 % ethanol can be blended with gasoline (The Gazette of India, 2002). In addition, Winrock International India* initiated the formation of
*Winrock International India (WII) is a non-profit organization working in the areas of natural resource management, clean energy and climate change.
Page 19
an “Ethanol Coalition of India” in 2000 to promote the development of fuel ethanol (Mishra, 2002).
Thailand In the autumn of 2002 Thailand hosted the 14th ISAF International Symposium on Alcohol fuels, entitled “The Role of Alcohol Fuels in Meeting the Energy, Environmental and Economic Needs of the 21st Century”. At this symposium many papers prepared in Thailand were presented, some of which gave information on the development of fuel ethanol production in Thailand. In addition a number of relevant papers reporting investigations and other activities in Thailand have been found in Internet searches.
In November 2001 the RFA reported that the Government of Thailand had approved the use of a 10 % ethanol/gasoline blend in order to increase the production of ethanol in the country. One reason why the government wants to increase the content of ethanol in gasoline is the need to be less dependent on imported oil and to promote the use of domestically produced energy carriers (Renewable Fuels Association, 2001). It has also been reported that there is an attempt in Thailand to replace MTBE by ethanol (World Association of Beet and Cane Growers, 2001). One way to stimulate this replacement is seen to be a plan to decrease the excise tax on ethanol mixtures.
According to the literature there are five or six main potential sources of ethanol in Thailand, including sugar cane, molasses and cassava (Ethanol Industry in Thailand, 2004) and sweet sorghum (Thanonkeo et al., 2002). The scope for producing ethanol from sweet sorghum has been investigated via a process presented by Thanonkeo et al . In addition, production of ethanol from bagasse and rice straw has been studied by Siwarasak and Wirivutthikorn (2002).
2.7. Fuel Ethanol in Australia
In a literature review prepared by the Orbital Engine Company (2002a) for Environment Australia it is reported that the first Australian examination (“trial”) of a blend of ethanol (15%) in gasoline was carried out from 1980 to 1983. There was then a long time lag to the second trial, which was conducted in the years immediately preceding 1998 with a 10 % blend of ethanol in gasoline. The 10 % figure seems to have been related to the situation in the USA, since the American car manufacturers agreed to accept a blend of up to 10 % ethanol in gasoline without changing the warranty conditions of their vehicles.
This is also reflected in a paper presented by Dr. Kemp (the Australian Minister for the Environment and Heritage), where it is stated that "The major automobile manufacturers have advised my Department that they accept the use of 10 per cent ethanol blends and that such blends will not affect vehicle warranties," (Ministry for the Environment and Heritage, 2003) According to the paper and other reports from Australia there is interest in blends with higher alcohol contents, and investigations have been carried out with blends of up to 20 % ethanol in gasoline and some conclusions from these investigations will be discussed below (Orbital Engine Company, 2003; 2004). The main results from these tests have been presented in comprehensive summaries in the cited reports.
In 2004, the ethanol production capacity in Australia amounted to 135 000 m3. Of this, around 55 000 m3 was used for blending with gasoline. About 30 – 35 000 m3 was exported for other purposes and the rest was used domestically, but not as an automotive fuel. There are plans to increase the production capacity of fuel grade ethanol incrementally by about 270 000 m3, in total, by building three new production plants. An interim production target will be half of this
Page 20
amount. However the production of 270 000 m3 of ethanol, less than the 360 million litres required to supply ethanol for an E10 blend in Queensland alone. (Boswell, 2004).
Today, ethanol is produced from sugarcane and wheat, but the possibility of using other feedstocks (such as barley, corn and sorghum) is discussed. There is also interest in producing ethanol from other biomaterials, such as wood, i.e. lignocelluloses (Cheung et al., 2003).
The discussion about fuel ethanol in Australia has heavily focused on two issues: future gasoline quality standards and labelling of the gasoline pumps.
In September 2000 a paper entitled “Setting National Fuel Quality Standards” was released by the Natural Heritage Trust on the “Proposed Standards for Fuel Parameters (Gasoline and Diesel)” and the “Revised Commonwealth Position”. One of the main positions taken by the Commonwealth was that the oxygen content in gasoline must be higher than 2.7 %, as proposed in the standards for gasoline, to allow the continued use of a 10 % ethanol-gasoline blend already available on the market. The proposal by the Commonwealth was that an exemption should be made for ethanol so as the standard could be the following when referring to “Summary of revised Commonwealth proposal for fuel quality standards” where the specification for gasoline is: “Oxygen content: 2.7 % (max) with an exemption for ethanol blends up to 10 %” (Natural Heritage Trust, 2000).
Noting the Commonwealth position, Environment Australia published a paper entitled “Setting the Ethanol Limit in Petrol” which officially invited the public to send in their views on the limit for ethanol blends in gasoline (Environment Australia, 2002).
After years of discussions, in which representatives of the petroleum industry, the Australian Automobile Association (AAA), various gasoline suppliers and the insurance company NRMA* (which covers cars inter alia), have been involved (the authors of this report conclude that NRMA is not willing to cover the risk for damage to cars that may be caused by a high percentage of ethanol in gasoline). The outcome of these discussions prevented Environment Australia (and thus the Government), from allowing higher alcohol contents than 10 % in blends with gasoline. NRMA has also been conducting research on ethanol gasoline blends used in motor vehicles (Australia Automobile Association, 2002; 2002a; NRMA, 2003) and found that there could be problems with higher alcohol contents. A study conducted by Apache Research Ltd. for NRMA showed that 10 % ethanol could be accepted, but the use of a 20 % blend led to increased wear (see section 3.1, below).
All those who were strongly opposed to higher ethanol contents than 10 % supported the 10 % limit and, in fact, welcomed the opportunity to use gasoline with that of blended ethanol. The AAA says that they support ethanol contents in gasoline of up to 10 %, and the policy of labelling ethanol blends at the gasoline pump. The opinion of the NRMA has been that no higher ethanol content than 10 % should be allowed “until comprehensive research shows that it will not damage fuel systems and engines” (Australian Automobile Association 2002; NRMA, 2002;
* National Roads and Motorists’ Association
Page 21
2002a). In a paper presented in 2003, Shell notes that the Australian Institute of Physics* (AIP) has been “taking positive steps towards achieving the Government’s [350 000 m3] target for bio fuels” by participating in various activities related to the further introduction of bio fuels, including ethanol. The position of the AIP is that the introduction of ethanol under the government policy should be viable if the consumers feel confidence in its use as a fuel (Shell, 2003). Early in 2003 BP announced that it had been delivering a 10 % blend of ethanol in gasoline, but was going to stop producing it since consumer confidence in ethanol blended gasoline was low (BP, 2003). In December 2003 BP announced that it will limit its marketing to a 10 % blended regular unleaded gasoline in Queensland after the middle of December 2003. However, Dr George Nicolaides of BP, admitted that ethanol blended gasoline fuels “have a role to play in Australia as a renewable fuel and as an octane enhancer” (BP, 2003a).
The actions taken by the petroleum industry, the AAA and NRMA obviously created pressure on Environment Australia and the Australian government since it resulted in the Minister for the Environment deciding to set a 10 % limit for ethanol blends in gasoline in April 2003. He also announced that he was going to appeal to the State Governments to require labelling at fuel pumps delivering ethanol blends (Federal Government, 2003; Federal Government, 2003a).
The decision taken by the Minister for the Environment is explained in papers released by the Ministry. One of the papers states that “ethanol blends for the Australian market means gasoline that, as tested in accordance with the Fuel Standards (Gasoline) Determination 2001, contains more than 1% ethanol”. It is also stated that “the ethanol blend may contain up to and including 10% ethanol; and a statement that the ethanol blend is the subject of this standard” (Kemp, 2003). In a second paper the standards for some of the fuel parameters are presented and in a third paper the labelling requirements are listed and it is stated that “If you sell an ethanol blend you will have to display a label” (Department of the Environment and Heritage, 2004 and 2004a). When delivering blended fuel from a pump the label must be displayed “as close as practicable to each nozzle that dispenses the ethanol blend and for retail supply special requirements are to be followed”. In Figure 2.3 a replicate of the label is shown.
Preparation of the position paper for the “Fuel Quality Standards Act 2000” (Office of Legislative Drafting, Attorney-General’s Department 2004) has started, and the Department of the Environment and Heritage has invited stakeholders to send in comments by by close of business, 18 February 2005 (Department of the Environment and Heritage, 2004a). A background paper for “Setting a Quality Standard for Fuel Ethanol” has been prepared by Hart Downstream Energy Services (Hart Downstream Energy Services, 2004).
* Australian Institute of Physics (AIP has gained recognition as a key representative body of Australia's petroleum industry).
Page 22
Figure 2.3. The Australian label for ethanol blended gasoline. (Department of the Environment and Heritage, 2004a).
Page 23
3. DATA AND EXPERIENCE
Data and experience related to the use of ethanol blended fuels are presented and evaluated. The materials selected for examination were largely reports and other papers presented during the last 10 years. When searching via the internet a great number of papers can be found, so a second selection criterion, applied to web-sourced materials was to exclude all texts that were not in report format, even if they were based on empirical studies. However, many papers from various authorities, universities and institutions have been of great value even if they have not been written in the form of a report, since they provide information about decisions taken or to be taken and research that will be presented eventually. It should be noted that this project does not consider the production of ethanol, the supply and delivery of ethanol blended fuel or associated costs.
Papers from lobby organizations were also often excluded since they tend to be prejudiced and to present conclusions without giving sufficient information about the basic conditions and data on which the conclusions are based. When examining reports dealing with blended fuel, wear of the vehicles and vehicle performance it soon becomes apparent that opinions differ among those concerned with the use of ethanol and the impact on vehicles of using ethanol. Data on air quality, health effects and emissions linked to the use of ethanol blended gasoline, are presented and discussed in two separate sections, 4 and 5, below.
3.1. Vehicle Performance
One of the objectives for this project is to find out whether it is possible to increase the content of ethanol in Swedish gasoline from about 5 % to a higher percentage without creating problems that would be unacceptable to the car manufacturers, cars owners and/or drivers. However, experience and data obtained in empirical studies have shown that the use of ethanol contents up to 10 to 15 % in gasoline should not create any serious wear of the vehicle/engine, but may influence drivability.
A comment on World Wide Fuel Charter (WWFC) was that WWFC should increase the maximum oxygen content in gasoline to 3.5% (by mass) in order to allow a blend of 10% ethanol in gasoline (WWFC, 2002; WWFC Comments, 200)
The response from WWFC is that the WWFC Committee selected a limit of 2.7 % as the general mass of oxygen in gasoline in order to assure correct operation of the engine. However, a footnote to this statement indicates that the Committee accepts the use of 10% ethanol in gasoline if the fuel conforms to the requirements set for the fuel.
Furthermore, the position of WWFC is that the level of 3.5% oxygen content for ethanol blends in gasoline is too high. There is a WWFC requirement for using co-solvents and inhibitors when methanol is used.
Due to the maximum oxygen level in gasoline WWFC do not allow an addition of 10% ethanol to gasoline which may already contain 2% MTBE despite the fact that this is allowed by US EPA. (WWFC, 2002; WWFC Comments, 200)
Page 24
The Orbital Engine Company in Australia has carried out extensive tests for the Australian government on vehicles fuelled with ethanol blended gasoline, focusing especially on its effects on the durability of their components (Orbital Engine Company, 2004)
• A Holden Commodore VN, 1990 model, which has an electronic fuel injection system, a three-way catalyst, a closed loop control system and runs on ULP (“unleaded petrol”) gasoline.
• A Ford Falcon XE, 1985 model, which has electronic fuel injection, open loop control systems and runs on LRP (low vapour pressure) gasoline.
• A Holden Commodore VK, 1985 model, which has a carburettor and runs on LRP gasoline.
According to the Orbital report the tests followed, as closely as possible, standard SAE protocols (J1748 for polymeric material, J1748 for metallic material and J1681 for material/component immersion testing). A 20 vol% ethanol gasoline blend was used as test fuel. The results from the 2000 hour testing and evaluation program can be summarized as follows:
• Metallic fuel system: various parts of the fuel system such as the fuel pump, the fuel injectors, metallic parts of the fuel regulator diaphragm, and the fuel pressure regulator showed corrosion, tarnishing and pitting.
• The fuel tank metal, the fuel sender unit, and the PCV valve/spool showed corrosion and pitting, tarnishing and the plastic filters were discoloured.
• Various parts of the carburettors and associated components of the carburettor-equipped car showed corrosion, pitting and tarnishing.
The general view derived from studying the international literature is that blends with up to 15 % ethanol do not have any serious effects on the performance and wear of the vehicle. Many reports and other documents deal with the use of ethanol, including its effects on performance and wear, but the most extensive reports focus on flexible fuel vehicles (FFVs), i.e. vehicles designed to be fuelled with up to 85 % ethanol in gasoline.
Car owner/driver acceptance of a new fuel, e.g. a fuel with a certain level of an alcohol in gasoline, is highly dependent on the cost of the fuel and the performance of the vehicle. Concerning drivability: “The most important aspect of performance (other than starting) is acceleration, both from a stop and at highway speeds in order to pass” and is a vital issue for customers according to McLean and Lave (2002). In the Science Fair Projects Encyclopedia (2004) it is said that both of the ethanol-gasoline variants “E10 and "E15", containing 10 % and 15% ethanol in gasoline, respectively, are “generally safe” for common usage in automobile engines. Adding a higher percentage of an alcohol like ethanol may affect the performance of the vehicle, especially its starting and drivability at low temperatures. These effects on the engine and vehicle may also result in increased emissions, due to sub-optimal operation of the vehicle’s emission control systems during the time lag until the engine and catalyst reach the normal temperature for a continuously running engine. However, ongoing development of engines and control systems for the fuel and emissions have resulted in considerable improvements related not only to emission performance but also to drivability. Further advances may solve some of the problems concerning the cold start parameters of the engines, thus improving their start-ability and emission performance when used with ethanol-gasoline blends. Although vehicle performance and wear of the engine and its control systems are linked to a number of different factors, of varying importance, many significant steps have been taken in recent years which will reduce these problems.
Page 25
3.2. Cold Starts and Driving
High levels of an alcohol (over 20 %) usually adversely affect cold starts and warming up in low temperature conditions since more heat is needed to vaporize alcohol than gasoline. Normally low levels, < 10 %, of alcohols in gasoline do not cause problems during cold starts and the warming-up phase of the engine, especially for modern vehicles (US Department of Energy, 1991).
Several methods and devices are available to improve the cold start and emissions during the warming up period. One recommended for use with FFVs is a specially designed catalyst presented by the National Renewable Energy Laboratory (NREL). A key feature of the catalyst tested by NREL is that it is insulated with a “Variable-conductance vacuum insulation” (NREL, 1996). Another suggestion is to use certain additives in the fuel, but this does not seem to be a good alternative for ethanol-gasoline blends with low alcohol contents. In Sweden an engine heater is commonly used to improve the cold starts and warming up of the engine.
3.3. Impact of Fuel
In the RFA (2002) paper the impact of adding ethanol to the base fuel on the physico-chemical properties of the fuel is also discussed. The properties considered are fuel volatility, vapour pressure, distillation properties, calculated drivability index, and vapour lock protection index in six classes (according to ASTM D 4814), oxygen content, water tolerance and gasoline additives. The following paragraphs summarise the impact of adding ethanol on these variables, as discussed in the paper. Fuel volatility: Adding ethanol to gasoline will increase the volatility, decrease the 50 % distillation point (T50), and affect both the drivability index and vapour lock protection. Vapour pressure: This is a measure of “front end” volatility, and a fuel with extremely high vapour pressure may cause problems with hot start ability, hot drivability and vapour lock. Distillation properties: Ethanol in gasoline will reduce the T50 value of the fuel, which may cause problems with older vehicles in warm weather. It has been shown that later models of fuel injected vehicles are less sensitive to a reduction in T50 than older cars. Drivability index: The drivability index is based on the relationship between the distillation temperature of the fuel and the cold start and warming up parameters of the vehicle. The following formula can be used to calculate the drivability index (DI): DI = 1.5 T10 + 3.0 T50 + 1.0 T90 Vapour lock protection index: ASTM D 4814 defines six classes of vapour lock production, as shown in Table 3.1.
Page 26
Table 3.1. ASTM D 4814 Vapor Lock Protection Class Requirements (Oak Ridge National Laboratory, 2002).
Vapour/Liquid (V/L)*# Vapour Lock Protection Class Test Temperature °C V/L, max
1 2 3 4 5 6
60 56 51 47 41 35
20 20 20 20 20 20
* At 101.3 kPa pressure (760 mm Hg.) #The mercury confining fluid procedure of test Method D 2533 shall be used for gasoline-oxygenate blends. Test Method D 5188 may be used for all fuels. The procedure for estimating temperature-V/L may only be used for gasoline (ASTM D 4814e).
The definition according to the ASTM standard ASTM D 4814 is that the Vapour Lock Index, according to the ASTM standard ASTM D “is the ratio of the volume of vapour formed at atmospheric pressure to the volume of fuel tested in Test Method D 2533” (Renewable Fuels Association, 2002). As can be seen in Table 3.1, test method D 2533 is to be used for oxygenate-gasoline fuel blends. The requirement for each of the classes is that the maximum vapour to liquid ratio formed at the test temperature (TV) must be at most 20 (Oak Ridge National Laboratory, ORNL, 2002), as shown in the table. The vapour lock protection index is defined as TV/L20, meaning that higher TV/L temperatures are required for summer grades of ethanol-gasoline blends and lower TV/L20 temperatures are required for winter grade blends, which are more volatile. The ORNL has presented two examples, one of which is related to vapour lock protection class 1, which would have a TV/L20 temperature of 60°C while class 6, which is more volatile would have a TV/L20 temperature of 35°C. In practice this is reflected in the fact that the RVP standards for winter and summer grade gasoline in Sweden are 95 kPa and 70 kPa, respectively, and that the vapour lock class depends not only on the climate but also the altitude. A salient issue to consider is whether a 10 % ethanol content in Swedish summer gasoline would meet the ASTM vapour lock protection standards. The authors of this report strongly believe that adding 10 % ethanol to Swedish winter grade gasoline would not create any problems in meeting the ASTM vapour lock protection standards. Oxygen content: The standard for the oxygenate content in gasoline is set on a weight basis, as can be seen in Table 3.2 (Renewable Fuels Association, 2002). Table 3.2, Ethanol content and oxygenate content in fuels. Fuel ethanol content, volume % Fuel Oxygen Content, weight %
5.7 2.0 7.7 2.7 10 3.5
Since there are differences in the density of different grades of gasoline compared to the density of ethanol the final content of oxygen will vary if the blending volume is fixed to a certain volume.
Page 27
Water tolerance: It is well known that ethanol has affinity to water, so appropriate measures must be taken when blending ethanol with gasoline and during the distribution of ethanol-gasoline blends. According to the RFA the water tolerance of blended fuels is temperature-dependent, i.e. the tolerance is lower at low temperatures. A 10 % ethanol blend in gasoline will tolerate approximately 0.5 % water (v/v) at temperatures of 15.5 °C or more, while the water tolerance is 0.3 % (v/v) water at approximately -12 °C (Renewable Fuels Association, 2002). In a report prepared by Krause and finalized by Korotney the possibility of phase separation occurring in ethanol-gasoline blends contaminated with water has been discussed.. When phase separation occurs in a blend of ethanol in gasoline, water starts to remove ethanol from the gasoline and another phase, containing both ethanol and water, forms in addition to the gasoline and ethanol phase.. The impact of the water-ethanol phase on the engine is greater in a two-stroke engine than in a four stroke engine, were it may combust in the engine. In a two-stroke engine the ethanol-water phase will compete with the gasoline-oil mixture and reduce the lubricating ability of the lubricating oil. However, phase separation normally only occurs in the presence of liquid water in the ethanol-gasoline blend (Krause and Korotney, 1995). In a study of a blend of anhydrous ethanol and unleaded gasoline the wear was not found to be unusually high (US Department of Energy, 1991). However, with 11 % water in ethanol a significant increase in the wear occurred, since the engine temperature was reduced. Formic acid and water vapour in the combustion gases during low temperature combustion of alcohols containing high percentages of water may oxidize metal components in the engine. The acidity of the combustion gases in combination with the lubricating ability of the lube oil will significantly increase the wear rate. It is well known that the concentrations of formaldehyde and acetic acid are relatively high in the combustion gases when methanol or methanol-gasoline blends are used in a combustion engine. However, certain amounts of these gases are also formed, in addition to considerable amounts of acetaldehyde and acetic acid, during the combustion of ethanol or ethanol-gasoline blends.
According to the US DOE, those who are responsible for delivering and blending alcohols in gasoline are aware of the risks and consequences of contamination of alcohol fuels by water. The possibility of increased wear of components in the engine is not the only risk, since water in the fuel can also adversely affect the start ability and driving performance of the engine. Methods for blending alcohols in gasoline are discussed in section 1.2. However, since the risk for water contamination of the fuel is a potentially serious problem Chevron in the US has decided to use ethanol only in areas where appropriate terminal facilities (i.e. where ethanol is properly distributed) are available, in order to ensure the quality of the blended alcohol-gasoline fuel (Chevron, 2004).
Gasoline additives: Various additives may be used in gasoline, such as detergent/deposit additives. For ethanol-blended gasoline the RFA recommends that ethanol producing member companies should “treat their ethanol with a corrosion inhibitor to ensure that any final blend is properly treated for corrosion protection”. The RFA has established recommendations for blending ethanol in gasoline, for storage tanks, for distribution, and at customer delivery points, for protecting pumps and meters. Many of these recommendations are certainly known by suppliers of ethanol blended fuels. However one of the recommendations is of great importance for those filling cars with ethanol blended gasoline, namely that: “When first converting to an ethanol program it is advisable to recalibrate meters
Page 28
after 10-14 days to ensure that the change of product has not caused any meters to over-dispense” (Renewable Fuels Association, 2002).
The effects of adding ethanol to gasoline on fuel properties have been discussed by Chandra Prakash in a report prepared for Environment Canada (Prakash, 1998). She notes, inter alia, the advantage of using ethanol as an enhancer of the octane number of the blended fuel. As an example she refers to a comparison (summarized in Table 3.3) of ethanol blended gasoline with neat gasoline.
Table 3.3. Ethanol and gasoline octane numbers. Property Ethanol Gasoline RON 102-130 90-100 MON 89-96 80-92 (RON+MON)/2 96-112 85-96 Blending RON 112-120 90-100 Blending MON 95-106 80-92 Her essential message concerning the octane number is that the high octane rate of ethanol increases the value of the blended fuel. She also points out that the higher octane number of the blended fuel confers advantages in terms of fuel efficiency for later models of vehicles since they are commonly equipped with knock sensors, which retard the ignition timing in the event of knocking. In such cases the fuel will be more efficiently matched to the engine. The fact that ethanol has a lower heating value than gasoline may affect the performance of the vehicle, since the presence of an alcohol in gasoline will lean out the fuel, resulting in some loss of engine power. According to Prakash this is somewhat offset by the fact that adding ethanol to gasoline results in a higher volume of combustion gases, which increases the pressure in the cylinder and thus increases the power efficiency by 1 to 2 percent. The negative effects of blending ethanol in gasoline in terms of increased volatility, enleanment (which affects the cold start ability), fuel economy and the water miscibility of ethanol are also discussed in the cited report (Prakash, 1998). These effects have been discussed in other sections of the present report, but not the risk for deposits forming in the engine caused by cold starts at low temperatures. Additives compatible with the engine oil must be used in order to avoid deposits building up.
Besides pollution from exhaust emissions there are also issues related to the handling of ethanol/gasoline blends, for instance their storage in underground fuel tanks and the potential contamination of groundwater due to leaks, which are addressed in a number of reports. Powers et al. (2001) state that several modelling studies predict that the presence of ethanol in gasoline will probably increase the BTEX (i.e. benzene toluene, ethylbenzene and xylene) plume from a leakage. According to Deeb et al. (2002) and Lovanh et al. (2002) simulations indicate that the benzene plume is likely to increase by 16 to 34% in the presence of ethanol. Neither the true extent of the potential increase nor the risks for leakage to the ground soil have been well characterised. In addition there are indications in the reports that biodegradation of benzene is severely inhibited by the presence of ethanol.
Page 29
3.4. Impact of Lube Oil
During the survey of the international literature no report was found that specifically recommended the use of special oil when driving vehicles with up to 10 % ethanol in gasoline. For FFVs some vehicle manufacturers claim that a special lubricating oil is needed (still, see under section 3.6). However, according to information from the National Ethanol Vehicle Coalition, Ford no longer require the use of synthetic oil for the lubrication of engines designed to be fuelled with E85. Other car manufacturers like Chrysler may still require special oil for their FFVs (National Ethanol Vehicle Coalition, 2004).
Professor Mathur (Delphi) has reported that he has completed a three-year trial on the road using approximately one hundred government vehicles. He claims that there has not been any problem related to aspects such as storing the fuel, fuelling the vehicles and other issues (Mathur, 2004). One interesting observation is that analyses of samples of lubricating oils have detected no differences in comparisons of the use of ethanol blended fuel and neat gasoline.
A question to consider is whether (and if so to what extent) components in the lubrication oil like sulphur and other chemicals will react with acidic combustion products. The Alliance of Automobile Manufacturers (AAM) and the Association of International Automobile Manufacturers (AIAM) have proposed that additional data on “fuel sulphur effects at near-zero” levels of sulphur should be compiled. They also recommended that data should be gathered on the effects of fuel oxygenates to provide a knowledge base for the California Air Resource Board (CARB) (AAM/AIAM, 1999).
In a Vehicle Buyer's Guide for Consumers published by the US DOE the owners of FFVs are advised to check their service manuals to ensure that the right fuel oils are used (US Department of Energy, 2002). Two of their recommendations for a FFV when using ethanol gasoline blends are:
• “Special engine lubricants may be required when fuelling with ethanol. If you are driving a (FFV), check the owner's manual or consult with the vehicle manufacturer to be sure that you are using the right engine oil.
• When ordering replacement parts for an FFV make sure to let the dealer know you are fuelling with ethanol”.
No such recommendations from the US DOE concerning low ethanol-gasoline blends, i.e. those with 10 % or less of ethanol, have been found.
3.5. Impact on Service and Maintenance
A marked lack of wide-ranging, extensive studies of ethanol-gasoline blends with 10 to 30 % ethanol contents was found in the literature search, although blends with up to 25 vol% ethanol in gasoline have been used in Brazil for many years. This is espeally tru for studies of later years models of vehicles. Exceptions are the investigations carried out in Australia referred to in sections 2.7 and 7.1.
Additional service and maintenance instructions to be followed by the service personal and car owners have not been (and are still not) generally issued for FFVs. However, according to the National Renewable Energy Laboratory (NREL) car manufacturers have agreed to apply the same warranties for FFVs as those of vehicles being run on neat gasoline, and the maintenance
Page 30
practises of dealers are very similar for these two types of vehicles. It has also been noted by Ford in literature concerning their Ford Taurus that no special service instructions are needed.
• “FFVs have been used in private and government fleets for years. The technology is proven, and the knowledge base about them is strong. Manufacturers stand behind them with standard warranties equal to those of gasoline vehicles. Dealer maintenance practices for FFVs are very similar to those followed for gasoline vehicles” (NREL, 2003).
• In the information given by Ford Motor Company concerning their FFVs there are: “no special service or maintenance issues with the Taurus Flexible Fuel Vehicle” (Ford Motor Company, 2003).
For vehicles using up to 10 % ethanol in gasoline there does not generally seem to be any need for special service instructions, and for vehicles available on the US market the use of blends with up to 10 % alcohol has been accepted by the car manufacturers. This benefit has been noted by many authors, including Launder (2001) from Michigan State University in a study of the development of ethanol blends in gasoline in the USA from 1970 onwards. As early as 1980 Chrysler, Ford, and General Motors stated that a blend of 10 % ethanol in gasoline would be covered by their warranties for their cars on the US market. By 1995, the same year that Ford started production of FFVs, almost all US car manufacturers were recommending the use of 10 % ethanol in gasoline according to Launder.
3.6. Compatibility and Wear
Studies on engine wear have shown that there is only a slight risk that the use of blends with low alcohol contents will result in increased wear. According to the Canadian Renewable Fuel Association (CRFA) all automobiles sold in North America (the USA and Canada) are “designed with full warranty protection even when they are operated on ethanol-blended gasoline” (Canadian Renewable Fuel Association, 2004). This is consistent with the view of the Australian Consumers Association (ACA) to its members, as stated in the following quotation, “Most of the manufacturers say gasoline containing more than 10 % ethanol can damage car engines, and their new car warranties won’t cover such damages” (Australian Consumers Association, 2003).
According to the CRFA’s website this warranty is valid for ethanol concentrations up to 10 % and no engine modification is needed (www.greenfuels.org/ethanolterms.html).The CRFA also says that a higher engine compression ratio is advisable for ethanol-gasoline blends above 10 %, but then the warranty may not be valid since increasing the compression ratio may damage the engine. Many car manufacturers in Europe and Japan sell vehicles in North America, and thus the assumption of the authors of the present report is that the design of vehicles on the European market, including Sweden, may allow use of ethanol-gasoline blends with at least 10 % alcohol.
The most serious reported risk associated with blending an alcohol, especially methanol, in gasoline is the potential formation of water vapour and formic acid during low temperature combustion (US Department of Energy, 1991). The proposed solutions of the problem are to use “acid neutralizers in lubrication oils”, “surface treatment of engine parts” and more “frequent replacement of lubrication oil or higher quality synthetic oils or a redesign of conventional engine lubrication oils”. In the report by the US DOE the following materials are listed as subject to degradation due to high concentrations of alcohols since ethanol may not be compatible with them:
• Lubricating oils. • Terne steel (in gas tanks).
Page 31
• Cylinder walls, fuel pumps, carburettors. • Polymers, elastomers, rubbers, plastics (hoses). • Polymethane. • Cork gasket material. • Leather. • Polyester bonded fiberglass laminates.
Hsieh et al. (2002) highlight the further potential problem, which may especially apply to older cars, that alcohol tends to react with rubber and they advise that modern cars should be designed to be compatible with the use of alcohol blended gasoline. Many authors of papers dealing with alcohol fuels claim that most problems associated with the use of alcohol, especially methanol, as a fuel for vehicles have occurred in older cars.
According to Hammel-Smith and his colleagues at the NREL, the physico-chemical characteristics of alcohol are different from those of gasoline, which may affect various components, especially in the fuel system (Hammel-Smith et al., 2002). A possible solution could be to use a special corrosion-inhibiting additive. The cited paper also discusses findings reported by other authors. The Oak Ridge National Laboratory has, for example, reported that use of 15 % ethanol-gasoline blends appears to be incompatible with parts of the fuel system according to tests carried out by the Technical Research Centre (VTT) in Finland. Eight out of ten carburetted cars tested showed more or similar wear when compared with gasoline fuelled vehicles. Unfortunately, no information about the two other vehicles appears to be provided in the cited paper.
It was also noted by the Oak Ridge National Laboratory that “Du Pont had found that highly fluorinated fluorohydrocarbons provided the best resistance to either highly aromatic gasoline or to ethanol”. Hammel-Smith et al. (2002) have reported, following material tests extending over many years, that these or similar materials may be used in modern vehicle systems. In the report by Hammel-Smith et al. it is also said that “few, if any incidents have been reported on 10% blends associated with ‘cylinder wall wash’.”
In the investigation by Minnesota State University (referred to above) the use of a 30 % ethanol-gasoline blend did not cause more than normal wear to the engines (Bonnema et al., 2004).
Joseph Jr., representing the Brazilian Automobile Manufacturers Association, has presented a study entitled “Vehicular Ethanol Fuel”, describing experience with the use of ethanol-gasoline blends – both anhydrous (99.3 %w) and hydrous (93.2 %w) – in cars in Brazil (Joseph Jr., 1998). One aspect discussed was the effects of ethanol blended gasoline relative to neat gasoline. Brazilian experience suggested that the relative compatibility of the blends with plastic materials was “good” and their tendency to cause the formation of gum deposits was “low”. Another conclusion was that a 22 % ethanol blend is more corrosive towards metals than gasoline. On the other hand it was felt that gasoline was as corrosive towards copper strips as a 10 % ethanol gasoline blend. The conclusion of the Joseph Junior presentation is that use of a 10 % ethanol-gasoline blend had no apparent detrimental effect on vehicle performance.
In its Industry Guidelines, Specifications, and Procedures the FRA states that o-rings and seals used in meters for neat ethanol should be “designed to withstand ethanol”. On the other hand it states that no accelerated wear has been seen in gasoline meters which are used for ethanol-gasoline blends (Renewable Fuels Association, 2002). However, it also advises that the meters should be recalibrated “10-14 days” after switching to the distribution of ethanol blended gasoline, as noted in section 2.3.
Page 32
The Guidebook from the US DOE mentioned above provides information on solutions to problems related (inter alia) to fuel sampling, one of which may be to check the fuel facilities since their materials may be incompatible with the use of ethanol. There are indications that one potential problem is excessive wear of the nozzles and hoses etc. in the equipment used (US Department of Energy, 2001).
For blends with low ethanol contents (max. 10 %) there has been shown to be no difference between using them and neat gasoline. The engine wear that occurs when using a 10 % ethanol-gasoline blend was studied by Apache Research Ltd in Australia, who found that “there is no additional or unusual wear to that normally expected”, and that there was no increase in wear or reduction of TBN (total base number) compared to corresponding parameters when using neat gasoline (Apace Research Ltd, 1998).
There seems to have been an ongoing agreement between the Australian Institute of Petroleum, the Federal Chamber of Automotive Industries and the Australian Automobile Association that a 10 % ethanol content in gasoline is acceptable, but not more, because higher ethanol contents will result in “loss of drivability, loss of fuel economy and accelerated wear of engine components and fuel lines”. In addition it will have an effect on the warranty provisions for the vehicle (Australian Automobile Association, 2002).
The ethanol production industry has not agreed to the ethanol content of ethanol-gasoline blends being limited to 10 %, and claims that 10 to 20 % ethanol in gasoline has been used in vehicle fleets since 1992. The industry also made an agreement with a university to study the effects of higher blends of ethanol in gasoline (Department of the Environment and Heritage, 2002).
Several vehicle manufacturers have stated that their vehicles can be run on ethanol-gasoline blends with a 10 % ethanol content without any problem. For example, the Nissan Motor Co., Ltd, which noted approvingly, in a paper released in 2005, that it has been stated in “the News” that “the Minister “the Minister of the Energy Ministry together with the Thai Automotive Industry Association and major fuel suppliers such as the Petroleum Authority of Thailand (PTT), Bangchark Petroleum and Shell announced that the use of gasohol in cars is one way to reduce fuel imports and promote the production of gasohol in Thailand” (Nissan, 2005).
In the cited paper Nissan says that two grades of gasoline are used in Thailand, RON 91 and RON 95, and that MTBE has been added to both of them to date. The essential message from Nissan is that the cost of MTBE can be saved by replacing MTBE with ethanol without decreasing the octane number of the fuel when compared with the gasoline used. Furthermore Nissan states that “Nissan gasoline engines that are equipped with the injection system (EGI) can run on gasohol without any ensuing problem” and that “No modification is required to use gasohol, just open the fuel tank lid and fill it up. You can change back to normal gasoline at anytime, no need to wait until the tank is empty”.
In a series of papers Chevron has discussed, inter alia, issues related to oxygenated fuels and especially ethanol blends in gasoline (Chevron, 2004), in one of which, entitled “Oxygenated Gasoline”, it is stated that in “modern” motor vehicles equipped with engine control systems that adjust the air-fuel ratio, oxygenated gasoline will perform well. However, in vehicles with carburettors or systems for fuel injection that do not control the air-fuel ratio, oxygenate in the fuel may result in a too lean air-fuel mixture”. In addition, the volumetric fuel consumption will increase by 2 to 3 percent, on average, according to Chevron when oxygenated gasoline is used. As early as 1978 gasoline containing 10 % ethanol was being marketed in Nebraska, USA.
Page 33
In California the use of MTBE and other ethers has been banned since 2004, and other states are considering similar bans (Chevron, 2002a). Considering all the available information, from other sources as well as Chevron, it seems likely that ethanol will soon be the only oxygenate that can be used in the USA to satisfy federal requirements for oxygen in gasoline.
In the complete report (Chevron, 2002a) Chevron discusses the implications of the observation that “Methanol is Not Ethanol” in that they have different physico-chemical characteristics. According to Chevron:
• Blends of gasoline with methanol are more corrosive towards metals and cause more rapid deterioration of elastomers in the fuel system.
• Methanol-gasoline blends are not authorized by many manuals for vehicle owners. • The vapour pressure of a methanol-gasoline blend is significantly higher than that of a
corresponding ethanol-gasoline blend. • Methanol is toxic.
In addition, the following performance-related issues have been highlighted by Chevron:
• Compared to neat gasoline, ethanol/gasoline blends need more heat to evaporate, which can reduce drivability.
• Blending ethanol in conventional gasoline, if it is not adjusted for such blending may result in a fuel with too high volatility (in this context the alcohol’s previously mentioned effect on the VL = 20 temperature is relevant).
• Since ethanol increases the volatility of the fuel, adding it has not been a viable option for summer reformulated gasoline.
• Ethanol blended gasoline is not to be mixed with neat gasoline that has not been adjusted for such blending, since the resulting commingling will result in the RVP of the fuel in the tank exceeding standard limits.
• Conventional gasoline can dissolve up to 150 ppm water at 21 °C, depending on its aromatics content. An ethanol-gasoline blend with 10 % ethanol can dissolve up to 6000 to 7000 ppm water at 21 °C. Phase separation may occur if ethanol blended gasoline is transported in pipelines.
• Some metal components in the engine fuel system will rust or corrode if water or acidic compounds are present in the fuel system. According to Chevron “additional water dissolved in oxygenated gasolines does not cause rusting or corrosion, but water from the phase separation of gasoline oxygenated with ethanol will, given time”.
3.7. Impact of Vapour Lock
Vapour lock is caused by the fuel flow to the engine being reduced as a result of vapour formation, typically caused by high temperatures, while the vehicle is being driven. Vapour lock can also make it impossible to start the engine. This problem may be exacerbated in carburettor-equipped vehicles.
Vapour lock is linked to the vapour pressure of the fuel, which is a measure of the front end volatility∗ of the fuel. Fuels with extremely high vapour pressure may cause drivability and hot start problems as a result of vapour lock. Since the addition of an alcohol to gasoline will
∗ Front-end volatility: A term applied to the volatility of the lower boiling-point fractions of gasoline.
Page 34
increase the volatility of the fuel, there is a risk that it will also cause vapour lock to occur in hot weather or at high altitudes.
A paper published by Chevron recommends that fuels should not exceed specified Vapour Lock Index (VLI) values in order to avoid problems such as vapour lock and hot fuel. The following formula has been developed for calculating the VLI based on the vapour pressure (in kPa) and percent evaporated fuel at 70 °C: VLI=10(VP)+7(E70). The normal range for the VLI, according to Chevron, is 800 to 1250, and protection from vapour-linked problems is greatest at the lower end of the range (Chevron, 2002).
Page 35
4. AIR QUALITY AND HEALTH EFFECTS Air quality can be considered at three levels: global, regional and local. From a global perspective, the most important greenhouse gases are nitrous oxide, carbon dioxide and methane, all of which affect the global climate. Increased use of bio-based fuels, especially as blending components in gasoline, is expected to decrease the net production of carbon dioxide from fossil fuels in vehicles, which is an important issue for sustainable development. By introducing bio based fuels the net production of fossil carbon dioxide from vehicles is expected to decrease with increased amounts of bio based blending components in gasoline which is an important issue for sustainable developments.
Colón et al. (2001) have compared the urban air levels of organic compounds in Sao Paulo, Brazil, and the Los Angeles basin, USA. In Sao Paulo it is estimated that ethanol or ethanol-gasoline fuel blends account for approximately 40% of the total fuel used, but the corresponding level in the Los Angeles basin is much lower, hence the urban air in Sao Paulo is much more strongly affected by the use of ethanol as motor fuel.. It was found that the ambient air levels of volatile organic compounds measured in Sao Paulo were substantially higher than those in Los Angeles. For instance, mean concentrations of mono ring aromatics, volatile aldehydes and “simple” alcohols (mainly ethanol) were 2 - 3, 5 - 10 and 10 - 100 times higher, respectively. Alkanes (C4-C11, n-alkanes) were slightly increased in Sao Paulo. The ambient levels of organic compounds in the Los Angeles basin used by Colón in the comparisons were based on measurements made by the US EPA in the year 1997 (Lonneman, 1998). A study regarding carbonyls in urban air, collected in Rio de Janeiro, Brazil, revealed that of the 61 carbonyl compounds measured the most abundant were formaldehyde and acetaldehyde, with mean concentrations of 10.8 + 4.1 and 10.4 + 4.6 ug/m3, respectively (Grosjean et al., 2002).
Maclean and Lave (2000) have investigated air quality trade-offs from automobiles fuelled by alternative fuels. They state that comparisons can be misleading if the vehicles used are dissimilar. One of the fuels considered was E85 i.e. 85% ethanol and 15% gasoline. Aakko and Nylund (2003) investigated an FFV running on E85 and found that when the temperature was lowered from 23 ºC to –7 ºC formaldehyde and acetaldehyde emissions increased (the latter approximately four-fold; from 4 to 15 mg/km driven).
Exhausts from mobile sources such as motor vehicles are chemically very complex. The chemical compounds emitted range from gaseous, liquids to particles (solids) and may also be distributed between particles and the gas phase depending on the physical properties of the compounds. Particle emissions consist mainly of carbon particles onto which a variety of compounds are adsorbed. Up to 10-40 % by weight of the particles can be extracted from the carbon matrix with organic solvents (National Research Council, 1982). Such an extract is often referred to as the soluble organic fraction (SOF).
Several factors affect the chemical composition of the exhaust emissions, including the fuel, fuel quality, engine lubricating oil, engine wear, exhaust after treatment, driving conditions and ambient temperatures. Ambient temperature driving conditions, which of course depend on seasonal variations, can have a major impact on emissions, especially for Otto engines, both with and without three-way catalysts (Almèn et al., 1997) at low ambient temperatures from +20 ºC down to –20 ºC or lower. Investigations of light duty diesel engines have indicated that they are relatively unaffected by the ambient temperature compared to investigated Otto engines. This
Page 36
could be due to the differences in the combustion mechanisms of Diesel and Otto engines. Aakko and Nylund (2003) investigated exhaust emissions from an FFV running on E85 at temperatures of +20, 0 and –7 ºC, and concluded that the emissions of CO, HC and total particles increased as the temperature was lowered while NOx emissions were only slightly increased.
Another important factor affecting the chemical composition of exhaust emissions generated in the combustion process in an engine is the service and maintenance history of the vehicle/engine. Extremely high levels of both regulated and unregulated emissions have been detected in exhaust emissions from gasoline fuelled vehicles that have been poorly serviced and maintained, i.e. incorrectly functioning engines or so-called high emitters (Sjödin et al., 2000). High emitters should be mended or eliminated from the car fleet in general.
Armstrong (1995) has evaluated ethanol as an individual compound and states that it is readily degraded in the environment, so human exposure to it is anticipated to be very low. Furthermore, abundant information is available on the metabolism of ingested ethanol, which strongly suggests that environmental exposure to ethanol will have no adverse health impact on humans. Average ambient levels of ethanol in Porto Alegre, Brazil, where 17% of the vehicles run on ethanol have been found to be 12 ppb. Animal studies have found that the Lowest Effect Level (the lowest level to give a detectable response) of ethanol is 45 ppm, which is approximately 4000 times higher. The dose for a person living in Puerto Alegre might be about 0.5 mg ethanol, which is a negligible dose.
In section 5.3 a selection of exhaust constituents that may have adverse effects on the environment or health of animals and humans is listed and discussed.
Page 37
5. EMISSIONS In an investigation by the Swedish government entitled “Alternativbränsleutredningen*” (SOU, 1996) it was proposed that a thorough chemical characterization of exhaust emissions (regulated and unregulated exhaust constituents) of gasoline blended with alcohols should be carried out. Furthermore, it was suggested that bio assays, such as mutagenicity tests, TCDD-receptor affinity tests and neurotoxicity tests, should be included in the risk evaluation. The risk criterion was that the modified fuel alcohol/gasoline blend should not have any greater potential environmental and health impact than a baseline gasoline fuel. However, an updated set of compounds and classes of compounds that should be considered is discussed below. 5.1. Regulated exhaust emissions
Emissions that are regulated by law (Lagen, 2001) are carbon monoxide (CO), unburned fuel hydrocarbons (HC), nitrogen oxides (NOx) and, for diesel cars, particles. The methods used to determine regulated pollutants have been developed for application to conventional fossil based gasoline and diesel fuels. These methods are: chemiluminescense detection for NOx, nondispersive infrared detection (NDIR) for CO, gravimetric analysis for particulates and flame ionization detection (FID) for HC. The chemical constituents of HC are, by definition, hydrocarbons which consist solely of carbon and hydrogen atoms. However, the chemical compounds emitted include compounds other than pure hydrocarbons (see below) in relative abundances that vary depending on the fuel used, so the “HC” signal from the FID tends to be underestimated. This is because the hydrocarbons and partially oxygenated compounds have different response factors, as widely reported in the scientific literature (Table 5.1). Consequently, to make a valid comparison of HC emissions from gasoline and ethanol blended gasoline as fuels the comparison must be made compound by compound to avoid over- or under-estimations. This requires the development of a method enabling the separate detection of hydrocarbons and alcohols (at least) in exhaust emissions.
Table 5.1. Sensitivity of the flame ionization detector towards selected compounds relative to that of the hydrocarbon n-heptane (C7H16), which is set to 1.00 (Diez, 1967). Hydrocarbons Alcohols Organic acids Methane 0.97 Methanol 0.23 Formic acid 0.01 Ethane 0.97 Ethanol 0.46 Acetic acid 0.24
Emission measurements must be carried out as part of the type approval of the vehicle according to relevant legislation, for example the European regulations (current EU Directive 70/220/EEG with amendments). There is also a need for emission testing to generate emission factors for use in emission inventories and air quality studies. Characterisation of emissions from vehicles is also essential for research purposes. Emission tests are commonly carried out according to standard procedures to enable data generated at different laboratories or during different projects to be compared. There may also be a need to generate emission factors for local traffic situations,
* Investigation of alternative fuels.
Page 38
in which case specific driving patterns (driving cycles) may have to be followed when testing the vehicles, depending on the regulations in force.
5.2. Theoretical Discussion about HC Emissions
From a strictly chemical perspective, hydrocarbons consist solely of the elements carbon and hydrogen. When using gasoline as fuel in an Otto engine, the unburned fuel hydrocarbons (HC) in the exhaust consist mainly of unburned gasoline which itself largely consists of hydrocarbons. However, when using gasoline/ethanol blends as fuel the uncombusted fuel constituents include both unburned gasoline (which consists mainly of hydrocarbons as noted) and uncombusted ethanol. Thus, the HC emissions measured in the diluted exhaust consist of both hydrocarbons and ethanol (alcohol). From a legal perspective, HC emissions are regulated by law (see section 5.1), but not ethanol emissions. This means that reported HC emissions from vehicles fuelled with alcohol/gasoline blends are overestimated, due to the contribution of the alcohol* contents in the exhaust emitted from the vehicle, and the larger the alcohol contents present in the exhaust, the greater the error in estimated HC emissions.
Assume, for example, that a vehicle is run on gasoline and has HC emissions of 0.15 mg/km (i.e. uncombusted fuel hydrocarbons), and that the same vehicle is run on a gasoline blend and the measured “HC” emissions are also 0.15 mg/km (consisting of both uncombusted fuel hydrocarbons and uncombusted ethanol) in comparative tests.
The standard analytical method used for determining hydrocarbons in motor vehicle exhaust is to use a Flame Ionization Detector (FID), which can be regarded as a “carbon counter”. The relative sensitivity of an FID for each of the hydrocarbons methane, ethane, propane and pentane is approximately 1 (Dietz, 1967). The corresponding value for ethanol is 0.46. Using these relative sensitivity factors, and assuming that only hydrocarbons are present in the exhaust the HC emission factor will be 0.15 mg/km, but if only (100%) ethanol is present in the exhaust the ethanol emission factor from the vehicle is in reality 0.33 mg/km However, if only ethanol is present in the exhaust the “HC” emission measured is still 0.15 mg/km but should be practically zero as no hydrocarbon is present in the exhaust.
The above discussion highlights the need to distinguish between HC and alcohol contents in vehicle exhaust, especially when alcohol gasoline blends are used as fuel. An updated method needs to be developed for HC measurements from a legal perspective. This also means that a standardized method needs to be developed.
5.3. Unregulated Exhaust Emissions
It is well known that the addition of alcohols to gasoline fuel affects the unregulated exhaust emission constituents (Egebäck and Bertilsson, 1983). For instance, addition of methanol to gasoline increases the exhaust emissions of unburned methanol, formaldehyde, and methyl
* Other compounds, such as alcohols/aldehydes, also contribute to the signal from the FID.
Page 39
nitrite. Corresponding additions of ethanol to gasoline increase the exhaust emissions of unburned methanol, ethanol, formaldehyde, acetaldehyde, methyl nitrite and ethyl nitrite.
The US EPA has estimated that more than 20,000 individual chemical compounds are emitted from diesel fuelled vehicles (US EPA, 1990), approximately 500 of which have been positively/tentatively identified in the scientific literature. This means that more than 97 % of the estimated compounds emitted from diesel vehicles are unknown (as are, therefore, their health effects). However, a selection of unregulated exhaust constituents is considered below that are considered to be important and to have potential health effects on animals and humans, and thus should be monitored and reduced in exhaust emissions from automotive sources. Greenhouse gases and smog-forming compounds are also considered. The list of such compounds is expected to be updated and modified according to future findings.
Alcohols
When alcohols are used as blending components in gasoline, uncombusted alcohols from the fuel are emitted in the exhaust in various amounts. These uncombusted alcohols in the exhaust emissions should be measured since there is a risk that the “HC” signal from the FID will be overestimated, leading to estimates of HC emissions from alcohol blended gasoline fuels being higher than they really are (see Regulated exhaust emissions regarding HC section 5.1).
Aldehydes
Aldehydes are known to be irritants, they may induce allergic reactions and formaldehyde is considered to be a carcinogen (CARB, 1989). Aldehydes of special interest are formaldehyde and acetaldehyde. Using ethanol as a blending component in gasoline results in increased emissions of both formaldehyde and acetaldehyde (Egebäck and Bertilsson, 1983). According to Aakko and Nylund (Aakko and Nylund, 2003) significant increases in aldehyde emissions occur at relatively low ambient temperatures (-7 ºC). The effect is expected to be even greater at lower ambient temperatures than -7 ºC, especially for ethanol-gasoline blended fuels.
Alkenes
Alkenes such as ethene, propene and 1,3-butadiene can be potentially metabolized by endogenous enzymes to reactive metabolites, which have the potential to initiate cancer. For instance, the compound 1,3-butadiene is metabolized to ethylene oxide in both animals and humans (Törnqvist et al., 1988; 1991). According to Schuetzle et al. (1994) significant sources of 1,3-butadiene are the olefins in the fuel. By blending gasoline with ethanol the “fuel olefin” content decreases, suggesting that emissions of alkenes are reduced when it is used rather than neat gasoline. However, this hypothesis needs to be experimentally confirmed.
Alkyl nitrites
Methyl and ethyl nitrite are mutagenic (Törnqvist et al., 1983; Wild et al., 1983), hence they are potential carcinogens. Alkyl nitrites are formed from uncombusted alcohol reacting with nitrogen oxides (NOx) in exhaust plumes. From vehicles fuelled with methanol/gasoline blends and methanol/diesel blends methyl nitrite is formed (Johnsson and Bertilsson, 1982). Both methyl and ethyl nitrite are formed in exhaust plumes from vehicles fuelled with ethanol-gasoline blends (Egebäck and Bertilsson, 1983).
Page 40
Monoaromatics
Monoaromatic compounds emitted from vehicles include benzene, toluene, ethyl benzene and xylene, which are often collectively called BTEX. According to the California Air Resources Board (CARB, 1998) benzene is a known human carcinogen and may cause leukaemia through occupational exposure (Törnqvist and Ehrenberg, 1994). A source of BTEX emissions from vehicles is the BTEX content of the fuel used, emitted in the uncombusted fuel constituents. However, BTEX can also be pyrosynthesised in the combustion process from the fuel or lubricating oil constituents.
Particulate emissions
Particlulate emissions are measured on a weight basis i.e. through gravimetric determination using a dilution tunnel technique at a diluted exhaust temperature below 52 °C. Exposure to diesel exhausts clearly induces lung tumours in rats. These neoplasms may be caused by the particle fraction of the exhaust (International Agency for Research on Cancer, IARC, 1983; 1989; Camner et al., 1997). Due to the findings that TiO2 and carbon black particles, with no genotoxic compounds adsorbed on them (i.e. “clean” particles) can also give rise to lung cancers in rats (Pott, 1991; Pott and Heinrich, 1990; Heinrich et al., 1993) interest in particles per se has increased. Important particle parameters in general are their size, number, surface area and chemical composition. Studies by Heinrich et al. (1995) indicate that particle size is a very important parameter. The Institute of Environmental Medicine (Karolinska Institute, Sweden) has published a report which concludes that it is not currently possible to tell if a non-specific particle factor or a direct genotoxic effect of material adsorbed on the particles is responsible for causing lung cancer (Camner et al., 1997). Therefore, the particles emitted should be chemically analysed with respect to both their size and numbers.
Peroxyacetyl nitrate
In a study by Gaffney et al. (1997) field measurements taken in Albuquerque, New Mexico, were used to compare atmospheric levels of peroxyacetyl nitrate (PAN) associated with the use of different fuels. Levels were measured before and after introduction of a 10% ethanol gasoline fuel blend (>99%) and the cited authors detected increased levels of PAN and aldehydes during the wintertime. A study which is more valid during summertime conditions in Porto Alegre, Brazil, (Grosjean et al., 2002) indicates that aromatics and alkenes have a major role, and acetaldehyde and ethanol minor roles, as precursors to PAN in urban air – in contrast to a report prepared by the Orbital Engine Company (2002) for Environment Australia, which states that acetaldehyde is particularly important since it reacts with NOx, forming PAN in the atmospheric photochemical system. In the report it is stated that acetaldehyde emissions increase as the ethanol content in the blended gasoline fuel increases. This conclusion is supported by the results of several other investigations.
Polycyclic Aromatic Compounds
Polycyclic Aromatic Compounds (PACs) are a numerous group of mutagenic carcinogenic compounds, of which a subgroup (Polycyclic Aromatic Hydrocarbons or PAHs), consists of mutagenic carcinogenic hydrocarbons (IARC, 1983: 1989). Each PAH has a relatively large number of hydrocarbons with two or more condensed aromatic rings. However, in Sweden are the PAHs phenanthrene, fluoranthene, pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, dibenz(a,h)anthracene, dibenzo(a,l)pyrene, methyl anthracenes/phenanthrenes, retene and benzo(ghi)perylene recommended by the Swedish
Page 41
Environmental Protection Agency (SEPA) for air monitoring programs in 1999, however published in 2002 (Boström et al., 2002). Recommended guideline value concentrations in ambient air are set to 0.1 ng/m3 for benzo(a)pyrene (B(a)P) and for fluoranthene 2 ng/m3 in Sweden (Boström et al., 2002). So far B(a)P is the only PAH whose concentration in ambient air will be regulated by European Commission and the limit value will most probably be set to 1 ng/m3. However, at present the European Parliament has not made a final decision about the limit value according to Kyrklund (Kyrklund, 2004).
Nitrogen dioxide
Nitrogen oxides (NO and NO2) are formed by the oxidation of nitrogen from the air in the combustion process. An important parameter for the formation of nitrogen oxides is the combustion temperature i.e. increased combustion temperature results in increased nitrogen oxide emissions. Nitrogen dioxide (NO2) is a compound that plays a role in respiratory diseases, especially those of asthmatics and children (Nitschke, 1999). It should be noted that nitrogen oxides (NOx) are regulated pollutants that are determined jointly, as the sum of NO and NO2 contents rather than as individual components.
Greenhouse gases
Greenhouse gases of most interest are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), all of which interact with the radiative energy fluxes in the atmosphere, thereby increasing the average temperature of the earth. In Table 5.2 the Global Warming Potential (GWP) for selected greenhouse gases is shown. The GWP indicates the relative contribution of a molecule of a greenhouse gas compared to a molecule of carbon dioxide, for which GWP is set to one. According to Rodhe (2005), the background concentration in the atmosphere of carbon dioxide is 375 ppmv (yearly variation, +/- 2 ppmv), while the background concentrations of methane and dinitrogen oxide (nitrous oxide) are 1.75 ppmv and 0.315 ppmv, respectively. By multiplying the concentration of a greenhouse gas and its respective GWP, its relative contribution to the global warming effect can be estimated. Clearly, the most important greenhouse gas is carbon dioxide, due to its relative abundance in the atmosphere.
Table 5.2. Global Warming Potential (GWP) and the relative contribution to the global warming effect (RCGWE) of selected compounds.
Compound GWP Concentration ppmv
GWP x ppm % RCGWE
Carbon dioxide, CO2 1 375 375 74 Methane, CH4 23 1.75 40.3 7.9 Dinitrogen oxide, N2O 296 0.315 93.2 18
Quinones
A recent publication by Xia (Xia et al., 2004) shows that a quinone-enriched polar fraction from a diesel particulate extract was more potent than PAH with respect to toxic effects in RAW 264.7 cells macrophage-like cells derived from tumours induced in male BALB/c mice by the Abelson murine leukemia virus. Quinones are a group of organic compounds that consist of diketones (carbonyls) which contain oxygen and are present in both diesel particles (Schuetzle et al., 1981) and ambient air (Cho et al., 2004). Aromatic quinones have previously been identified and measured in gasoline particulate exhaust extracts (Schuetzle et al., 1981; Alsberg et al., 1985). The origin of the aromatic quinones is not fully understood if it is related to the gasoline fuel as uncombusted quinones (initially in the fuel) or if they are formed in the combustion
Page 42
process.. It is well known that fuel properties affect the chemical composition of the exhaust emitted from engines. For instance, adding ethanol to gasoline increases the emission of aldehydes (carbonyls). It is possible that increasing the ethanol content of gasoline-ethanol blends causes similar increases in quinone emissions, but there are no empirical data related to this issue as yet.
5.4. Characterisation of Exhaust Emissions
In a relatively recent publication He et al. (2003) present a study of exhaust emission characteristics from an engine with an electronic fuel injection (EFI) system with and without a three-way catalyst (TWC) system. The engine was run on neat gasoline, and both 10 % ethanol- (E10) and 30 % ethanol- (E30) gasoline blends (see section 1.2, Table 1.1). The engine out emissions at idle speed using E30 as fuel it was observed that HC, CO and NOx emissions was reduced and ethanol and acetaldehyde emissions was increased. It was also observed that the TWC system reduced acetaldehyde emissions, but had a low conversion efficiency for ethanol.
In Table 5.3 mean emission factors are shown from three TWC-equipped cars running on 3, 6 and 10 vol. % ethanol-gasoline blends (Schifter et al., 2001). It is difficult to interpret or to draw firm conclusions from the data in the table, as they are mean values from three cars. However, NOx, benzene and acetaldehyde emissions increased with increasing ethanol contents, while CO and formaldehyde emissions and the ozone formation factor (g O3/g Non Methane Organic Gases, NMOG) decreased.
Table 5.3. Mean emission factors from three TWC-equipped cars running on 3, 6 and 10 vol. % ethanol gasoline blends (Schifter et al., 2001). Emission 3 %
Ethanol 6 % Ethanol 10 % Ethanol Ethanol
effect CO, g/km 3.11 2.89 2.97 - HC, g/km 0.23 0.21 0.22 0 NOx, g/km 0.42 0.42 0.48 + g O3/g NMOG 3.12 3.09 3.08 - Benzene, mg/km 7.22 7.38 8.11 + Butadiene, mg/km 0.83 0.77 0.83 +/- Formaldehyde, mg/km 1.32 0.78 1.01 - Acetaldehyde, mg/km 1.12 1.25 1.62 + In Table 5.4 the mean fuel economy and mean evaporative emissions from the three TWC-equipped cars running on 3, 6 and 10 % ethanol gasoline blends are shown. Table 5.4. Mean fuel economy and mean evaporative (Evap) emissions from three TWC-equipped cars running on 3, 6 and 10 % ethanol-gasoline blends (Schifter et al., 2001).
3 vol % Ethanol
6 vol % Ethanol
10 vol % Ethanol
Ethanol effect
Fuel consumption l/10 km 0.87 0.85 0.87 +/- Evap. diurnal, g/test 4.14 3.77 4.60 +/- Evap. hot-soak, g/test 0.46 0.44 0.68 +
Page 43
Regarding emissions of benzene, toluene, ethyl benzene and xylene (BTEX) a general conclusion is that as the ethanol content of the blended fuel increases the BTEX emissions are reduced (Orbital Engine Company, 2002) by the dilution of the base gasoline.
In a study carried out in Australia (Orbital Engine Company, 2004) the unregulated emissions such as BTEX and aldehydes were measured. The emission measurements were made using fuels comprising of 20% ethanol (E20) in gasoline and neat gasoline. Furthermore, the vehicle emissions were determined at both 6400 and 80000 km odometer readings. In Figure 5.1 shows average benzene emissions from five tested cars. The Holden car decreases its benzene emissions with increased driving distance. The benzene emission is lower when the E20 fuel is used as fuel and the emission is reduced at increased driving distance. Comparative benzene emissions from the Hyundai car is that benzene emissions increase as the driving distance increases which is valid for both fuels tested. Furthermore, the Subaru car has larger benzene emissions from the E20 fuel compared to neat gasoline. From the Figure 5.1 it can be concluded that there is a relatively large variation in benzene emissions due to fuel and accumulated driving distance and vehicle tested. Because of this, it is difficult to make firm conclusions with respect to benzene emissions vehicle dependency.
BENZENE EMISSION - GASOLINE VERSUS E20
0
1
2
3
4
5
6
7
8
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
EXH
AU
ST E
MIS
SIO
NS
mg/
km 6400 km80 000 km
HOLDEN FORD TOYOTA HYUNDAI SUBARU
Figure 5.1. Benzene emissions (mg/km) gasoline versus E20.
Figure 5.2 shows average acetaldehyde emissions from all vehicles tested. From the figure it can be seen that increased accumulate driving distance results in an increased acetaldehyde emission, however the Toyota car is excluded. This seems to be fuel independent. From the Figure 5.1 it can be concluded that the there is a relatively large variation in acetaldehyde emissions due to fuel and accumulated driving distance and vehicle tested. Because of this, it is difficult to make firm conclusions with respect to formaldehyde emissions vehicle dependency.
Page 44
ACETALDEHYDE EMISSION - GASOLINE VERSUS E20
0
0,5
1
1,5
2
2,5
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
EXH
AU
ST E
MIS
SIO
NS
[mg/
km]
6400 km80 000 km
HOLDEN FORD TOYOTA HYUNDAI SUBARU Figure 5.2. Acetaldehyde emissions (mg/km) gasoline versus E20.
Figure 5.3 shows average formaldehyde emissions from all vehicles tested. All of the tested vehicles had increased formaldehyde emissions with respect to increased accumulative driving distance. The relative emissions of formaldehyde are vehicle and fuel dependant.
FORMALDEHYDE EMISSION - GASOLINE VERSUS E20
00,10,20,30,40,50,60,70,80,9
1
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
EXH
AU
ST E
MIS
SIO
NS
[mg/
km] 6400 km
80 000 km
HOLDEN FORD TOYOTA HYNUDAI SUBARU
0 0
Figure 5.3. Formaldehyde emissions (mg/km) gasoline versus E20.
Summing up, from Figures 5.1 to 5.3 due to accumulative driving distance the function of the catalysts is deteriorating which results in increased emissions of benzene, acetaldehyde and formaldehyde emissions. The gasoline fuel used contains up to 500 ppm sulphur which is extremely large compared to gasoline available on the Swedish market which is expected to have an impact on the exhaust emissions.
Page 45
6. FUEL ENERGY CONTENT – ENGINE POWER. Since ethanol has a significantly lower energy value than gasoline its addition may affect the engine’s power even though the octane number of ethanol is higher than that of gasoline. Since there has been a lack of standard protocols for measuring the octane numbers RON and MON for ethanol the presented range for them is quite wide: 102 – 130 for RON and 89 – 96 for MON according to Environment Canada. Furthermore, the octane numbers for gasoline vary depending on its composition. The octane numbers presented for ethanol blended gasoline are 90 – 100 for RON and 80- 92 for MON (Prakash, 1998; Environment Canada, 2005).
The engine’s power output depends on the energy content per unit volume fuel injected into its combustion chamber. The reduction in energy content per unit volume fuel caused by adding five different percentages of ethanol to a certain blend of gasoline is shown in Figure 6.1.
-10
-5
0
5
10
15
20
25
30
35
% EtOH in gasoline% change of fuel energyFuel energy content [MJ/l
CHANGE OF ENERGY WHEN BLENDING DIFFERENTPERCENTAGES OF ETHANOL IN GASOLINE
MJ/l%
Figure 6.1. The effect of blending ethanol with Swedish Class 1 (MK1) gasoline on the fuel’s energy content.
When adding ethanol up to 25 % the energy change may be sufficient for the driver to clearly detect a change in the engine’s power* during acceleration of the vehicle. However, vehicles produced today are designed to adjust the air-fuel ratio in order to compensate for changes in the fuel. It is well known that vehicles are equipped with systems for adaptive learning or adaptive memory, and according to information obtained from Web FAQs, “Modern adaptive learning engine management systems control the combustion stoichiometry by monitoring various ambient and engine parameters, including exhaust gas recirculation rates, the air flow sensor, and exhaust oxygen sensor outputs” (Hamilton, 2004).
The conclusion is that an addition of 10 to 15 % ethanol to gasoline will, to a certain degree, increase fuel consumption. However, in the literature study it was not possible to find a
* As the energy content (MJ/l) of ethanol gasoline blends is lower than that of neat gasoline the fuel consumption will most likely increase for the average driver.
Page 46
definitive percentage for the increase since it depends on a number of factors, of which the design of the fuel system of the vehicle and engine, the percentage of ethanol in the fuel and the driving pattern of the vehicle appear to be most important.
An issue to consider is whether the owner of the vehicle will recognize the increase in fuel consumption that may occur when ethanol is added to gasoline. In a report prepared by the Orbital Engine Company for Environment Australia concerning an investigation into the use of 20 % ethanol in gasoline it is stated that the “increase in fuel consumption ranges from 2.5 % to 7 % depending on the cycle and the vehicle”. In the same report Orbital also states that “Increases in fuel consumption of 5% or more are considered to be recognisable to the average driver” (Orbital Engine Company, 2003).
Results presented by Apache Research Ltd. from an investigation of the use of a blend of 10% ethanol in gasoline show that fuel consumption increased by 2.4 % when driving according to the US EPA City cycle and by 2.7 % when driving according to the Highway cycle (Apache Research Ltd, 1998). According to the statements by Orbital this increase in fuel consumption should not be detectable by an average driver.
In a paper from the Transportation Office of Energy Efficiency in Canada it is said that adding 10% ethanol to gasoline (E10) will result in a blend with an energy content equivalent to 97 % of the energy content of the base gasoline. Since this decrease in energy content will be partly compensated by the “improved combustion efficiency” of the ethanol blended fuel, the overall increase in fuel consumption when using E10 will be only 2 %. In comparison, increasing the speed of the vehicle from 100 km/h to 120 km/h will result in a 20 % increase in fuel consumption (Transport Office of Energy Efficiency in Canada, 2004).
Page 47
7. EVALUATION OF EMISSIONS AND FUEL CONSUMPTION In a paper released in 1992 the US EPA defined “Clean Fuels” as including “alcohols, electricity, natural gas, and propane” (US EPA, 1992). In the paper the EPA also declare that “Some vehicle fuels, because of physical or chemical properties, create less pollution than do today’s gasoline. These fuels are called “clean fuels.”
A key issue today is whether newly manufactured gasoline-fuelled vehicles equipped with an efficient emission control system emit more or less harmful substances than vehicles fuelled with any of the fuels mentioned in the paper from the EPA. It can also be questioned whether any automotive fuel used today can be defined as a “clean fuel” since all types of fuels generate pollution when burned in a combustion engine.
Concerning the use of a blend with a certain content of ethanol in gasoline it is quite clear, as already mentioned in this report, that there is a risk that emissions, especially of acetaldehyde, will increase, but those of benzene, toluene, ethylbenzene and xylene (BTEX) may decrease compared with the use of neat gasoline in the same vehicle. Whether (and if so to what degree) these changes will be better or worse overall in terms of the air quality and health has been considered in various studies, especially in the USA/California, and in this report. The most important issue to clarify is whether, and if so to what extent, the regulated emissions will change compared with the use of neat gasoline when switching to the use of a blend of ethanol/gasoline. Hammel-Smith and his colleagues at NREL have indicated that a key aspect concerning vehicle performance and emissions when using a blend of ethanol/gasoline of up to 17 to 24 % is that fuel control is able to compensate for a high oxygen content in the fuel (Hammel-Smith et al., 2002).
One of the conclusions to be drawn is that it is generally not certain that a higher blend of ethanol can be used in all vehicles currently available. Potential barriers in this respect are the age of the vehicles, their technological standards and their control systems. Electronically controlled fuel injection systems have long replaced carburettors and they are more advanced today in that new functions have been incorporated. The use of electronic mapped digital systems makes it possible to control ignition, fuel injection, emissions and automatic transmission in addition to other engine variables. According to the NREL these systems have been important in the evolution of the use of alcohols as automotive fuels (Hammel-Smith et al., 2002).
When considering the performance and emissions from motor vehicles, especially vehicles using blends of ethanol in gasoline, the technological status of the vehicle should be considered. It is accepted that adding an alcohol, i.e. ethanol, in gasoline will enhance the octane rate of the fuel. On the other hand it has been shown in section 6 of this report that blending ethanol in gasoline will decrease the energy content of the fuel, resulting in an increase of the volumetric fuel consumption. In vehicles equipped with advanced engine control systems the ability to exploit the higher octane rating compensates, to a certain degree at least, for the inevitable drop in the energy content of the fuel.
When considering the effect of blending ethanol with gasoline on emissions a factor that must be taken into account is that motor vehicles are sensitive to changes that affect the air/fuel ratio. This is especially true for vehicles equipped with older types of fuel systems, such as
Page 48
carburettors or open loop fuel injection systems. Newer models of vehicles equipped with closed-loop fuel injection systems, especially those with advanced closed-loop fuel injection systems with adaptive learning functions are less sensitive in this respect.
When using alcohol blended gasoline it has been observed that NOx emissions may increase compared to the use of neat gasoline due to the leaning effect of the alcohol. This effect does not generally occur when using alcohol blended gasoline in newer models of vehicles.
During the survey of reports presenting data and experience related to the use of ethanol blended gasoline some data from emission and fuel consumption measurements have been found. In the following sections these data and experiences are briefly described. When reading the tables and studying the figures it should be noted that presented data on HC emissions include components other than hydrocarbons, as discussed in sections 5.2 and 5.3.
7.1. Evaluation of Emissions in Australia
In Australia a number of investigations and emission tests have been conducted during the last five to seven years in a project initiated by the Department of the Environment and Heritage entitled “Market Barriers” (2004). The project which finally included different parts was performed as an initiative of the Department of the Environment and Heritage project “Market Barriers to the uptake of Bio fuels – Testing Petrol Containing 20 % Ethanol (E20)” (Orbital Engine Company, 2004). The tests carried out included comparative measurements of emissions from engines from engines running on neat gasoline and a blend of 20 % ethanol (E 20) in gasoline in pairs of the following five vehicles.
• Holden Commodore VX. • Ford Falcon AU-III. • Toyota Camry Altise. • Hyundai Accent. • Subaru Impreza WRX.
Two types of gasoline (AEN* Summer ULP and AEN Perth ULP; designated ULP and PULP, respectively) were used as base gasolines for blending with ethanol. The difference between the two types of gasoline, according to Orbital, is as follows: “In summary, there are some small but quantifiable differences to be taken into account when comparing trends over the accumulated mileage and across some of the vehicle fleet using the ULP stock. The base fuel differences are however relatively insignificant with respect to distillation and constituency when compared to the change introduced by the ethanol blending” (Orbital Engine Company, 2004).
The investigation presented in the cited report is an extension of earlier tests (Orbital Engine Company, 2003). The aim of the later study, named 2B, included an assessment of durability over accumulated mileage and the following measurements and analyses at specific “breakpoints” (Orbital Engine Company, 2004):
• Exhaust emissions measurements. • Fuel consumption measurements. • Engine oil analysis.
* Australian Energy News (AEN)
Page 49
• Engine wear analysis at completion of mileage accumulation. • Fuel system analysis at completion of mileage accumulation.
Since the effects of using ethanol-gasoline blends on engine wear have already been considered in this report discussion here is mainly focused on the emissions. The emission testing included both regulated and non regulated emissions and the main results were as follows. The emission testing included measurements of both regulated and non regulated constituents and the tests were carried out in accordance with the Australian test procedure ADR37/01 for monitoring emissions from light duty vehicles, which includes the US 75 test cycle. The main results were as follows
As can be seen in Table 7.1 there was only a small difference in emission levels when comparing the two fuels at 6 400 km, but the emission performance of E20 was considerably worse than that of the neat gasoline at 80 000 km.
Table 7.1. Regulated emissions at mileages of 6 400 km and 80 000 km. Fuel Type
Gasoline E20 Difference (%) Regulated
Emission (g/km) 6 400 km 80 000 km 6 400 km 80 000 km 6 400 km 80 000 km
THC 0.173 0.097 0.065 0.123 -10.9 26.8 CO 0.710 1.279 0.665 1.881 -6.3 47.1 NOx 0.122 0.177 0.155 0.445 27 151.4 To elucidate the reasons for the observed deterioration in emissions with accumulated mileage associated with use of the blends, the cited authors studied factors that could contribute to their impact on emissions. Since one of the factors could be the catalyst system, detailed analyses of the individual vehicles were carried out, especially with respect to loss of catalyst efficiency. The catalyst efficiency was studied for each of the three phases of the test cycle, of which Phase 1 (the first 505 sec) is the cold start phase – according to the test procedure the vehicle is initially equilibrated to a room temperature of around 20 to 25 °C. The three phases can be seen in Figure 7.1.
Figure 7.1. The three phases of the test cycle followed during the emission test.
Figures 7.2, 7.3 and 7.4 show the difference in the efficiency of the catalyst found when using the 20 % ethanol blended fuel compared with the use of neat gasoline in each of the three phases.
Page 50
0
20
40
60
80
100
120
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
%
6400 km80 000 km
Holden Ford Toyota Hyundai Subaru
Phase 1 of FTP 75 Catalyst NOx Efficiency for the Vehicle Fleet at6000 and 80000 km - Gasoline vs E20
Figure 7.2. Phase 1 NOx catalyst efficiency when using E20 compared with neat gasoline after 6 400 and 80 000km driving
0
20
40
60
80
100
120
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
% 6400 km80 000 km
Holden Ford Toyota Hyundai Subaru
Phase 2 of FTP 75 Catalyst NOx Efficiency for the Vehicle Fleet at6000 and 80000 km - Gasoline vs E20
. Figure 7.3. Phase 1 NOx catalyst efficiency when using E20 compared with neat gasoline after 6 400 and 80 000km driving.
Page 51
0
20
40
60
80
100
120
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
%
6400 km80 000 km
Holden Ford Toyota Hyundai Subaru
Phase 3 of FTP 75 Catalyst NOx Efficiency for the Vehicle Fleet at6000 and 80000 km -. Gasoline vs E20
Figure 7.4. Phase 1 NOx catalyst efficiency when using E20 compared with neat gasoline after 6 400 and 80 000km driving.
The three figures show several interesting features:
• There is a considerable difference between the pairs of vehicles. For the Toyota vehicles there is very little difference in catalyst efficiency between use of E20 and use of neat gasoline.
• There is a difference in catalyst efficiency when comparing the three phases of the test cycle. As expected, the efficiency was considerably lower during Phase 1.
• The catalyst efficiency was somewhat higher, at least for some vehicles, during Phase 2 than during Phase 3.
• The most important observation to note is that the deterioration of the catalyst performance was considerably worse when using E20 than when using neat gasoline.
Another factor to consider when studying data from emission tests is the impact of sulphur in the fuel. Studies carried out for the American Lung Association of Minnesota have shown that sulphur in the fuel has a considerable impact on both regulated and unregulated emissions. There is reason to expect the deterioration of the vehicles tested after 80 000 km driving to be linked, to some degree, to sulphur in the fuel used in the tests carried out by Orbital. According to Orbital two grades of gasoline were used in the ethanol blends: unleaded gasoline (ULP) and Perth unleaded gasoline (PULP). The Australian gasoline specifications at the time of the tests show that the upper limits for the sulphur contents in ULP and PULP were 500 ppm and 150 ppm, respectively. A table taken from the report (Table 7.2) suggests that the ULP grade was used in the neat gasoline tests, but elsewhere it suggests that PULP was also used. Furthermore, it is not clear whether the same grade of gasoline was used for the ethanol-gasoline blends as that used for the neat gasoline tests, although it can be assumed that even a sulphur content of 150 ppm in the base fuel would have had a considerable impact on the emissions.
Page 52
Table 7.2. Emission data from tests with neat gasoline and 20 % ethanol-gasoline blends. 6 400 km 40 000 km 80 000 km % Difference Emissio
n g/km
ULP E20 ULP E20 ULP E20 ULP E20
THC 0.120 0.081 0.162 0.155 0.147 0.119 22.5 46.9CO 0.711 0.728 0.800 0.865 0.845 0.907 18.8 24.6NOx 0.100 0.083 0.106 0.126 0.134 0.208 34.0 150.6
Holden
CO2 256.7 267.6 259.3 265.3 256.8 260.7 0.0 -2.6THC 0.126 0.120 0.112 0.142 0.191 0.218 51.6 81.7CO 2.090 1.710 1.871 2.075 4.731 3.798 126.4 122.1NOx 0.125 0.265 0.171 0.174 0.457 0.481 265.6 81.5
Ford*
CO2 255.7 258.8 255.0 253.5 252.4 250.3 -1.3 -3.3THC 0.025 0.031 0.030 0.024 0.045 0.027 80.0 -12.9CO 0.551 0.457 0.873 0.671 1.063 0.895 92.9 95.8NOx 0.034 0.036 0.039 0.056 0.070 0.047 105.9 30.5
Toyota
CO2 247.5 248.4 235.1 293.8 235.1 236.6 -5.0 -4.7THC 0.041 0.046 0.049 0.065 0.051 0.112 24.4 143.5CO 0.304 0.345 0.472 1.155 0.45 1.821 48.0 427.9NOx 0.15 0.18 0.105 0.488 0.132 0.637 -12.0 253.9
Hyundai
CO2 168.8 172.0 166.4 163.3 166.5 165.8 -1.40 -3.60THC 0.050 0.041 0.079 0.084 N/A 0.104 58.0 104.9CO 0.388 0.288 0.697 0.936 N/A 1.023 79.6 225.0NOx 0.059 0.043 0.059 0.048 N/A 0.071 0.0 11.6
Subaru†
CO2 255.6 254.8 250.0 254.3 N/A 250.6 -2.2 -0.2
7.2. Evaluation of Emissions in Canada
A report with a limited‡ distribution from Environment Canada describes a series of comparative tests carried out on five vehicles using neat gasoline and ethanol-gasoline blends (with ethanol contents of 10%, 15% and 20%). The aim of the program was to compare emissions from the vehicles when using neat gasoline and oxygenated fuel (Augin and Graham, 2004). The vehicles used in the tests are listed in Table 7.3 and the fuel properties are shown in Table 7.4.
Table 7.3. Selected data for the tested vehicles. Vehicle Model
year Engine
displacement [L]
Number of cylinders
Transmission Test inertia [kg]
Pontiac Grand Am 1999 3.4 V6 Automatic 1590 Honda Insight 2000 1.0 3 Automatic 966 Chevrolet Silverado 1999 5.3 V8 Automatic 2160 Toyota Echo 2001 1.5 4 Automatic 1136 Honda Civic 2001 1.6 4 Automatic 1250
* AENFO02 results are based on tests conducted at 8 900 km rather than 6 400 km. † AENSU05 results are based on tests conducted at 7 600 km rather than 6 400 km. ‡ In the available edition of the report it is noted that “the report has not undergone detailed technical review by the Environmental Technology Advancement Directorate” Canada.
Page 53
Table 7.4. Selected data for the fuels used in the emission tests. Fuel properties SGC1 10 %
Ethanol 15 % Ethanol 20 % Ethanol
% C by mass 86.7 82.8 81.0 79.3 % H by mass 13.6 13.5 13.5 13.5 % O by mass - 3.7 5.5 7.3 Density [g/ml] 0.7453 0.7497 0.7519 0.7541 1Summer Grade Commercial baseline tests of fuel.
In this section the results from tests of regulated emissions are presented in the form of figures. A more complete set of emission data presented in the report by Augin and Graham is given in the Appendix 1.
The emission tests were carried out in accordance with the US Federal Test Procedure (FTP 75) and two repeats of each cycle were performed on each vehicle in order to provide a minimal measure of the repeatability, according to the authors of the report (Augin and Graham, 2004). The results of the emission tests are shown as means for the five vehicles in Figures 7.5 to 7.9 and Tables 7.5 to 7.7
ARITHMETIC MEAN OF CARBON MONOXIDE [CO] EMISSION (5 VEHICLES)
0,000,100,200,300,400,500,60
0 % EtOH 10 % EtOH 15 % EtOH 20 % EtOH
g/km
Figure 7.5. Mean emissions of carbon monoxide from the five test vehicles according to the
US EPA FTP 75 test procedure
Page 54
ARITHMETIC MEAN OF HYDROCARBON [HC] EMISSIONS (5 VEHICLES)
0,0000,0050,0100,0150,0200,0250,0300,0350,0400,0450,050
0 % EtOH 10 % EtOH 15 % EtOH 20 % EtOH
g/km
)
Figure 7.6. Mean emissions of hydrocarbons (HC) from the five test vehicles according to the US EPA FTP 75 test procedure.
ARITHMETIC MEAN OF OXIDES OF NITROGEN [NOx] EMISSIONS (5 VEHICLES)
0,0000,0100,0200,0300,0400,0500,0600,0700,080
0 % EtOH 10 % EtOH 15 % EtOH 20 % EtOH
g/km
Figure 7.7. Mean emissions of NOx from the five test vehicles according to the US EPA FTP
75 test procedure.
ARITHMETIC MEAN OF CARBON DIOXIDE [CO2] EMISSION (5 VEHICLES)
0,025,050,075,0
100,0125,0150,0175,0200,0225,0
0 % EtOH 10 % EtOH 15 % EtOH 20 % EtOH
g/km
Figure 7.8. Mean emissions of carbon dioxide from the five test vehicles according to the US
EPA FTP 75 test procedure.
Page 55
ARITHMETIC MEAN OF FUEL CONSUMPTION [FC] FOR (VEHICLES)
0,000,100,200,300,400,500,600,700,800,901,00
0 % EtOH 10 % EtOH 15 % EtOH 20 % EtOH
l/10
km
Figure 7.9. Mean fuel consumption of the five vehicles according to the US EPA FTP 75 test
procedure. Table 7.5. Emissions of aldehydes when using neat gasoline and three different blends of ethanol. Formaldehyde Acetaldehyde Vehicle ⇒ Honda Insight Grand Am Honda Insight Grand Am US FTP cycle mg/km mg/km mg/km mg/km 0 % Ethanol 0.019 0.603 0.143 0.298 10 % Ethanol 0.087 0.615 0.273 0.653 15 % Ethanol 0.491 0.516 0.373 0.926 20 % Ethanol 0.665 0.578 0.385 0.814 Table 7.6. Emissions of aldehydes when using neat gasoline and three different blends of ethanol. Formaldehyde Acetaldehyde Vehicle ⇒ Toyota Echo Honda Civic Toyota Echo Honda Civic US FTP cycle mg/km mg/km mg/km mg/km 0 % Ethanol 0.534 0.311 0.261 0.099 10 % Ethanol 0.360 0.870 0.379 0.721 15 % Ethanol 0.690 0.416 1.044 0.435 20 % Ethanol 0.671 0.572 1.311 0.597
Table 7.7. Emissions of specific hydrocarbons when using neat gasoline and three different blends of ethanol.BDL means below the detection limit for the instrument used Methane Ethylene Acetylene Ethylene Vehicle ⇒ Toyota
Echo Honda Civic
Toyota Echo
Honda Civic
Toyota Echo
Honda Civic
Toyota Echo
Honda Civic
US FTP cycle mg/km mg/km mg/km mg/km mg/km mg/km mg/km mg/km 0 % Ethanol 4.848 1.952 4.332 2.032 0.615 BDL* 1.311 0.640 10 % Ethanol 4.338 1.417 4.406 1.554 0.622 BDL 1.212 0.261 15 % Ethanol 4.406 1.212 4.344 1.423 0.640 BDL 1.293 0.553 20 % Ethanol 4.829 1.846 4.375 1.541 0.472 BDL 1.181 0.423
* BDL, Below Detection Limit.
Page 56
The following conclusions can be drawn from the comparisons of the use of ethanol blended fuel and neat gasoline:
• There are considerable variations in the emission levels between different blends of ethanol in gasoline and also between the different vehicles, especially when comparing vehicles with relatively large and relatively small engines.
• As expected, CO emissions decrease when replacing neat gasoline with ethanol blended fuel.
• HC emissions amount to less than 0.1 g/km and there is no clear indication whether blending ethanol in gasoline increases or decreases them.
• For all vehicles except the Toyota Echo NOx emissions increase when using a blend of ethanol in gasoline. For the Toyota vehicle they decrease.
• According to the presented data it is not clear whether the tailpipe emissions of CO2 increase or decrease when ethanol is blended with gasoline.
• As expected fuel consumption increases when using a blend of ethanol in gasoline. • The presented data provide clear indications that the emissions of formaldehyde increase
when using ethanol blended gasoline. • As expected, the acetaldehyde emissions increase when using ethanol blended gasoline.
The increase found in this investigation is also quite dramatic compared to corresponding increases found in other investigations discussed in this report.
The emissions of the measured specific hydrocarbons may either decrease or increase when using ethanol blended gasoline.
7.3. Evaluation of Emissions in the UK
A series of emission tests from five vehicles fuelled with a blend of 10% ethanol in gasoline has been carried out by AEA Technology plc*, Harwell, UK, on behalf of the UK Department of Transport. The aim of the tests was to generate data to be used as emission factors for gasoline-fuelled vehicles in the European context. The five vehicles tested are listed in Table 7.8. The Toyota Yaris was tested twice, since significant changes in the test procedure for unregulated emissions was made after the third vehicle was tested (Reading et al., 2002).
Table 7.8. Vehicles selected for emission testing and measurement of fuel economy. Vehicle
identifier Model Engine size
(litre) Emission Standards
Mileage km
1 & 6 Toyota Yaris 1.0 Euro III 22 000 2 Vauxhall Omega 2.2 Euro III 19 000 3 Fiat Punto 1.2 Euro II 51 000 4 VW Golf 1.6 Euro III/IV 21 000 5 Rover 416 1.6 Euro II 117 000
The fuels used for the tests were neat gasoline and a blend of 10% ethanol in gasoline. An interesting point to note is that the RVP of the neat gasoline and the blended fuel was 60 kPa 66.5 kPa, respectively.
* AEA Technology is a British technology company.
Page 57
The emission tests were conducted according to the current European test cycle, ECE/EUDC, and six of the test cycles designed by the Warren Spring Laboratory (WSL), as listed in Table 7.9.
Table 7.9. Test cycles. Cycle
identifier
Cycle Hot/cold start
Duration (seconds)
Target distance (km)
1 1 ECE/EUDC (Dir.98/69) Cold 1180 11.01 2 & 8 WSL Congested Hot 1030 1.91 3 & 9 WSL Urban Hot 1205 6.14 4 & 10 WSL Suburban Hot 480 5.52 5 & 11 WSL Rural Hot 586 10.95 6 & 12 WSL Motorway 90 Hot 306 7.96 7 & 13 WSL Motorway 113 Hot 256 8.18
The ECE/EUDC tests were carried out following the defined test procedures. The WSL-tests (results from the WSL tests are not presented here) were carried out following the standard procedure for the test laboratory.
It should be noted that only results from ECE/EUDC tests are presented here. In this section the results from tests of regulated emissions are presented in Figures 7.10 to 7.14. A more complete set of emission data presented in the report by Augin and Graham is given in Appendix 1.
COLD START ECE-EMISSIONS
00,5
11,5
22,5
33,5
4
CO THC NOX
g/km
Cold ECE gasoline
Cold ECE E10
Figure 7.10. Arithmetic mean of five vehicles tested according to the Cold start ECE emission test cycle.
COLD START EUDC-EMISSION
0,000,050,100,150,200,250,300,35
CO THC NOX
Cold EUDC gasolineCold EUDC E10
g/km
Figure 7.11. Arithmetic mean of emissions from five vehicles tested according to the EUDC Cold start emission test cycle.
Page 58
PARTICULATE EMISSIONS
0
2
4
6
8
10
Cold ECEgasoline
Cold ECE E10 Cold EUDCgasoline
Cold EUDC E10
mg/km
n.d.
Figure 7.12. Arithmetic mean of particulate emissions in tests according to ECE and EUDC Cold start emission cycles.
CARBON DIOXIDE EMISSION [CO2]
050
100150200250300
Cold ECEgasoline
Cold ECE E10 Cold EUDCgasoline
Cold EUDC E10
g/km
. Figure 7.13. Arithmetic mean of CO2 emissions in tests according to ECE and EUDC Cold start emission cycles.
FUEL CONSUMPTION
020406080
100
Cold ECEgasoline
Cold ECE E10 Cold EUDCgasoline
Cold EUDC E10
g/km
Figure 7.14. Arithmetic mean of fuel consumption in tests according to ECE and EUDC Cold start emission cycles. When comparing the data from the measurements of fuel consumption and emissions of regulated consitutents, PM and CO obtained using a blend of 10 % ethanol in gasoline with those obtained using neat gasoline the following conclusions can be drawn
• Fuel consumption is slightly increased. • CO- and PM-emissions are significantly reduced. • HC emissions are increased rather than decreased. • NOx-emissions are not significantly increased. • For some of the vehicles the tailpipe emissions of CO2 are decreased.
Page 59
The unregulated emissions are increased for a few components while the emissions are decreased in most cases. There are significant differences between vehicles, so for some vehicles the emissions are increased while for others they are decreased. As expected, the emission of acetaldehyde is increased in most cases. In the following table the numbers of increases (+) and decreases (-) are presented. Unfortunately, the unregulated emissions were only measured from three vehicles (plus a repeated measurement on the Toyota Yaris) and there are only four comparative measurements for benzene and nitrous oxide. As can be seen in Table 7.10, ammonia and PAH emissions were only measured from three vehicles.
Table. 7.10. Numbers of increases (+) and decreases (-) of unregulated emissions found in the tests using E10 compared to the tests using neat gasoline.
Changes Methane 1,3-butadiene
Form- aldehyde
Acet-aldehyde
Nitrous oxide
Benzene Ammonia ΣPAH
Increase 2 2 2 6 1 1 2 2 Decrease 7 7 7 3 3 3 1 1
7.4. Evaluation of Emissions in Sweden
An extensive investigation was carried out in Sweden in which the amounts of both regulated and non-regulated constituents emitted were compared when using various types of gasoline, LPG, diesel oil, different blends of methanol and a blend with 23 % ethanol in lead-free gasoline (E23) to fuel the following vehicles: five Saabs, five Volvos, one Volkswagen and one Mercedes Benz (Egebäck and Bertilsson, 1983).The tests were carried out on the following vehicles: five Saab, five Volvo, one Volkswagen and one Mercedes Benz. None of these vehicles was equipped with a catalyst. Of all the tests carried out only those involving use of E23 are of interest here. Considering both the amounts of the emissions, and their mutagenicity, the results suggest that use of E23 has both pros and cons. For example, when comparing the use of the 23% ethanol blend in gasoline with the use of neat gasoline, the emissions of ethanol and acetaldehydes increased, while emissions of polycyclic aromatic hydrocarbons (PAHs), especially benzo(a)pyrene (BaP), and NOx were somewhat lower, as were the mutagenic effects.
Since the temperature in Sweden is rather low in the winter -– occasionally down to minus 20 °C in the Stockholm area and minus 30 °C to minus 40 °C in the north of Sweden – and the mean temperature over the year is around plus 7°C in the Stockholm area (around 0 °C in the north of Sweden), the influence of the outdoor temperature on the emissions generated when using blended fuel and neat gasoline has been studied in a number of projects. It is well known that the use of an alcohol as a fuel in motor vehicles will increase the cold start emissions if the vehicle is not specially designed, i.e. equipped with an engine heater to improve engine starts. In one investigation (Egebäck et al., 1984) five well-maintained and carefully-checked cars without catalytic converters and one equipped with a three-way catalyst system were used. The vehicles were tested with unchanged fuel-air ratio settings (which were set for neat gasoline) with three different fuels. The fuels used were neat gasoline, 5% ethanol mixed with unleaded gasoline (E5), and 15% methanol mixed with a refinery-produced gasoline. All fuels were tested at 22 °C and the neat gasoline and ethanol mixture were also tested at +5° and -7°C.
Since nearly all light duty vehicles with spark ignition engines in Sweden today are equipped with a three-way catalyst the results of the emission testing at different temperatures are of
Page 60
interest for this report. A comparison of the emissions from the catalyst-equipped vehicle adapted for the use of alcohol in neat lead-free gasoline can be seen in Table 7.11.
Table 7.11. Emissions of regulated and non regulated emissions generated when using neat gasoline and E5 at different ambient temperatures. US-73 test cycle.
Fuel Temp
°C
CO
g/km
HC
g/km
NOx
g/km
Form- aldehyde mg/km
Acro- lein
mg/km
Partic- les
mg/km
Σ PAH
μg/km
B(a)P
μg/km
Fuel– cons.
l/10km
Gasoline 22 -5
2.27 3.90
0.23 0.50
0.22 0.28
6.6 2.3
<0.1 <0.1
8.2 30.1
49 -
0.9 -
1.09 1.26
E5 22 5 -6
2.50 3.10 2.90
0.36 0.25 0.43
0.20 0.30 0.36
6.3 4.2 1.4
1.2 <1´2 0.6
8.5 -
26.8
33 -
71
2.1 -
2.2
1.17 1.24 1.26
As can be seen from the figures in the above table the ambient temperature has a clear impact on the emissions, especially the particulate emissions and (thus) PAHs. Starting the engine at low temperatures is known to have a stronger effect on the emissions when using fuels with high contents of an alcohol than when using neat gasoline.
Important aspects of adding an alcohol to gasoline to consider are its effect not only on the exhaust emissions, but also on the evaporative emissions and how the fuel is changed by the addition. The aim of an investigation carried out by Laveskog and Egebäck (1999) for the Swedish Transport and Communications Research Board (KFB) was to study the effect of such additions on the RVP of the fuel and the evaporative emissions by adjusting the vapour pressure of the fuel.
Two types of gasoline were ordered from a refinery with vapour pressures (RPV) of 63 kPa and 70 kPa. To elucidate the strength of the effect of adding alcohol on the vapour pressure, samples were sent to a special laboratory for analysis (see “Fuel type”, Table 7.12). Both regulated and evaporative emissions were measured (the latter by the standardised SHED method. Ethanol blended fuel was compared with neat gasoline in order to determine how addition of ethanol affects the exhaust emissions and evaporative emissions compared with neat gasoline.
In total, three vehicles were each tested, once, with three test fuels with two different vapour pressures, yielding a total of 18 emission tests. Of the three cars tested, two were equipped with a catalytic converter. The two older cars – a Volvo 240 GL 1985 model and a Volvo 240 DL 1987 model – represented the technology level found in most cars sold in Sweden in the years following 1987 but only the latter had a catalytic converter.. The age of the oxygen sensors and catalysts of this car corresponded to approx. 50,000 km driving in traffic and they were designed to meet the Swedish A12 emission requirements. The other vehicle, equipped with a catalytic converter, was a Saab 9000T and the engine of this car was upgraded to correspond with a 1996 model, equipped with an adaptive fuel supply system, which automatically adjusts the rate of injected fuel according to the energy content of the fuel.
In addition to the emissions tests, the oldest car was also tested for evaporative emissions (SHED test) with the base gasoline (71.5 RVP), base gasoline (64 RVP) + 10% ethanol, and base gasoline (71.5 RVP) + 25% ethanol. The emission test results and the fuel consumption for the catalyst-equipped cars (Volvo DL and Saab 9000T) are presented in Tables 7.13 and 7.14.
Page 61
Table 7.12. Analysed and calculated values for test fuels. Fuel type Density Ethanol Energy content RVP, kPa g/mL % MJ/kg / MJ/l analysed Gasoline with lower vapour pressure (63 kPa)
Unmixed gasoline 0.750 <0.5 43.9 / 32.9 64 10% ethanol with gasoline 0.754 1) 10 42.2 / 31.8 2) 69 25% ethanol with gasoline 0.760 1) 25 39.7 / 30.2 2) 67 Gasoline with higher vapour pressure (70kPa)
Unmixed gasoline 0.755 <0.5 43.8 / 33.1 71.5 10% ethanol with gasoline 0.759 1) 10 42.1 / 32.0 2) 76 25% ethanol with gasoline 0.764 1) 25 39.6 / 30.3 2) 73 1) The density of ethanol is 0.791 g/mL at 18 °C according to 2) The energy content for ethanol is set to 27.1 MJ/kg
Table 7.13. Results of measurements of exhaust emissions during an urban driving cycle (UDC) according to US standards. Volvo 240 GL, 1985 model. Base gasoline, 64 kPa and 71.5 kPa. Car Amount
EtOH% Exhaust System
RVP kPa
CO g/km
HC g/km
NOX g/km
CO2 g/km
NMHC g/km
Fuel consump-tion l/10 km
0% EtOH Cat. 64 2.15 0.21 0.17 243 0.18 1.00 10% EtOH Cat. 69 1.82 0.17 0.18 240 0.15 1.03 25% EtOH Cat. 67 1.13 0.12 0.23 235 0.10 1.06 0% EtOH Cat. 71.5 2.11 0.17 0.19 243 0.14 1.01 10% EtOH Cat. 76 1.71 0.15 0.17 240 0.13 1.04
Volvo DL
25% EtOH Cat. 73 0.98 0.13 0.30 238 0.11 1.08
Table 7.14. Results of the measurement of exhaust emissions during an urban driving cycle (UDC) according to US standards. Saab 9000 CS, 1996 engine and engine management system. Base gasoline 64 and 71.5 kPa. Car Amount
EtOH% Exhaust System
RVP kPa
CO g/km
HC g/km
NOX g/km
CO2 g/km
NMHC g/km
Fuel consump-tion l/10 km
0% EtOH Cat. 64 1.16 0.06 0.14 242 0.05 0.99 10% EtOH Cat. 69 1.06 0.06 0.14 253 0.05 1.08 25% EtOH Cat. 67 1.23 0.05 0.13 250 0.04 1.13 0% EtOH Cat. 71.5 1.13 0.06 0.16 251 0.05 1.03 10% EtOH Cat. 76 1.09 0.06 0.15 244 0.05 1.04
Saab 9000 T
25% EtOH Cat. 73 1.25 0.07 0.12 238 0.06 1.08
Page 62
The CO and HC emissions were lower for the Volvo with a catalytic converter (Table 7.13). NOX emissions increased significantly when the gasoline with a vapour pressure of 64 kPa was used, but insignificantly with the 10% mixture. Despite the increase, the NOx emissions were still lower than the emission standards for this car. When gasoline with a vapour pressure of 71.5 kPa was used, all emissions decreased slightly with the 10% ethanol mix. With the 25% ethanol mix, NOX emissions rose from 0.19 g/km to 0.30 g/km. Efficiency also seemed to increase for this car, as the increase in fuel consumption for ethanol mixtures does not correspond to the reduced energy content of the test fuel.
In the car with an adaptive fuel supply system the effect of the ethanol mixture on CO emissions appears to be small, and the already very low level of HC emissions were almost totally unaffected (Table 7.14). NOX emissions were low, and showed a tendency to fall further as the ethanol content in the fuel increased. In the tests with the fuel with an RVP of 71.5 kPa, the tendency was the same as for the other cars – the fuel consumption was lower than expected when ethanol was added to the gasoline. The comparison of these two cars indicates that a car with an adaptive emission control system has better emission characteristics than a car without such a system.
Unfortunately, evaporative emission tests were only carried out on the Volvo 240 GL, 1985 model, which lacked a catalyst and canister for trapping fuel vapour. The results from the tests of this car are presented in Table 7.15.
Table 7.15. Evaporative losses from a car without evaporation controls, Volvo 240 DL, values from single measurements using fuels with 0% and 10% ethanol contents. HC emission g/test Increase in
emissions [%] Base gasoline, 71.5 RVP Base gasoline, 64 RVP +10% ethanol Base gasoline, 71.5 RVP +10% ethanol
37.2 38.9 42.4
- 4.6 14
7.5. Evaluation of Emissions in the USA
Few American studies were found in the literature survey that included measurements of emissions from commercial gasoline-based fuels with low alcohol contents suggesting that such measurements and studies have low priority in the USA, including California. However, it should be borne in mind that gasoline blended with 10% ethanol has been commonly used in many areas in the USA during the last 20 to 25 years. In contrast to the few reports found for blends with low ethanol contents a number of studies were found concerning emissions from FFVs.
In Minnesota a series of studies, initiated by the American Lung Association of Minnesota on the exhaust emissions from gasoline with low alcohol contents was found. The emission measurements were carried out at the University of North Dakota and the U.S. Department of Agriculture part-funded the work. In Minnesota a series of studies was commissioned by the American Lung Association of Minnesota on the exhaust emissions from gasoline with low alcohol contents (Aulich and Allen, 2002). The emission measurements were carried out at the University of North Dakota and the U.S. Department of Agriculture part-funded the work.
Page 63
Since 1999, the American Lung Association of Minnesota has been presenting studies on the impact on emissions of sulphur in the fuel and this issue has been discussed in a number of reports, which have shown that the emission rate depends considerably on the fuel used. The aim of the investigation discussed here was to further study the impact on emissions of the sulphur, benzene and olefins contents in gasoline. Minnesota gasoline is regulated under the Antidumping* Requirements introduced by the EPA and therefore it is of interest to study whether these requirements are fulfilled. The Antidumping Statutory Baseline Fuel Parameters set by the US EPA are shown in Table 7.16.
Table 7.16. EPA Statutory Antidumping Baseline Fuel Parameters. Summer Winter Average Annual Benzene, vol% 1.53 1.64 1.60 Aromatics, vol% 32.0 26.4 28.6 Olefins, vol% 9.2 11.9 10.8 RVP, psi 8.7 8.7 8.7 E200, vol% 41.0 50.0 46.0 E300, vol% 83.0 83.0 83.0 Sulphur, ppm 339 338 339
In 1999 the EPA introduced more rigorous emission standards, necessitating amendments to the fuel requirements. Since the sulphur content is one of the most important variables to reduce in the fuel, the EPA has established new requirements for the sulphur content in gasoline. According to the Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations the level of sulphur should be reduced, on average, to 15-40 ppm by weight and limited to a maximum of 80 ppm by 2006, see Table 7.17.
Table 7.17. Gasoline sulphur requirements according to the Federal Register, February 10, 2000. Gasoline sulphur standards for the averaging period beginning:
January 1, 2004 January 1, 2005 January 1, 2006 and subsequent
Refinery or Importer Average
N/A 30.00 30.00
Corporate Pool Average 120.00 90.00 N/A Per-Gallon Cap 300 300 300
The paper by Aulich and Allen of the Environmental Research Center, University of North Dakota, released by the American Lung Association of Minnesota, reports results from an evaluation of the impact of fuel sulphur on emissions. Samples of gasoline from three different gasoline suppliers were analyzed in detail and the impact of the fuel sulphur content was evaluated by using the resulting fuel data as inputs in the EPA’s MOBILE6.2 vehicle emission
* The purpose of the Antidumping Requirements is to ensure that conventional gasoline is not more polluting than it was in 1990. See Federal Register / Vol. 65, No. 230 / Wednesday, November 29, 2000 / Rules and Regulations.
.
Page 64
modelling software (US EPA 1993). In all, 23 samples of fuel containing 9.2 to 9.8 % ethanol were analyzed. The results of this part of the evaluation are summarized in Table 7.18.
Table 7.18. The estimated impact of fuel sulphur content on HC and NOx emissions. Holiday, Amoco and SA (SuperAmerica) are gasoline companies.
Holiday Amoco SA HC, g/km 0.069 0.095 0.098 NOx, g/km 0.31 0.50 0.51 Sulphur in Fuel, ppm 57 167 188 Two other components in the fuel that have a significant impact on the emissions are olefins and benzene. Benzene, a single component of gasoline, is known to have an effect on people’s health while olefins comprise a group of hydrocarbons that are known to be reactive in the atmosphere and may also cause deposits in the fuel system of the vehicle. Therefore, there is a need to keep the contents of these components as low as possible in gasoline.
The results of the evaluation conducted by Aulich and Allen on the impact of olefins and benzene in the fuel are summarized in Table 7.19.
Table 7.19. The estimated impact of the fuel contents of olefins and benzene on emissions of 1,3 butadiene and benzene. Holiday, Amoco and SA (SuperAmerica) are gasoline companies.
Holiday Amoco SA
1.3 Butadiene, g/km
0.00034 0.00071 0.00050
Benzene, g/km 0.0035 0.0064 0.0055 Olefins in Fuel, % 6 17 7 Benzene in Fuel, % 0.9 2.3 1.4
In another study presented by the American Lung Association of Minnesota (2003) the five blends of fuel listed in Table 7.20 were studied to assess the impact of sulphur.
Table 7.20. Average Fuel Properties (American Lung Association of Minnesota, 2003).
Holiday E10 BP E10 SA E10 Non-ethanol E85 Ethanol, vol% 10.2 10.2 10.3 0.0 78.4 Aromatics, vol% 23.6 24.2 24.3 30.5 N/A Olefins, vol% 8.5 15.5 7.7 9.1 N/A Benzene, vol% 1.0 1.9 1.1 N/A N/A Sulphur, ppm 49 212 90 103 8
The emission tests followed the “hot start” phase of the FTP-75 test cycle. The results of the tests carried out on a dynamometer and the data evaluation for the fuels listed in Table 7.19 are shown in Table 7.21.
Page 65
Table 7.21. The impact of fuel sulphur content on HC and NOx emissions.
Holiday BP SA Non-ethanol E85 HC, g/km 0.005 0.097 0.072 0.056 0.010 NOx, g/km 0.019 0.080 0.108 0.119 0.037 Sulphur, ppm 49 212 90 103 8
The cited study emphasises that:
• HC and NOx emissions for the Holiday fuel were under the detection limits, and the estimated levels of these emissions had to be based on their respective detection limits.
• For the BP fuel HC emissions were consistent with the predictions according to MOBILE6.2, but the levels were higher than for the other fuels tested.
• For the non-ethanol fuel with a sulphur content of 103 ppm, HC and NOx emissions were similar to those for the BP and SA fuels.
• The emissions of HC and NOx were much lower for E85, which had a sulphur content of just 8 ppm, than for the other fuels.
The measured emissions were significantly lower than the levels predicted by the EPA model, possibly because the tests were carried out with hot cycles while the EPA predictions were based on a complete, cold start FTP cycle.
7.6. Fuel Consumption
The consumption of fuel is either measured and presented as fuel consumption (L/10 km or L/100 km), or as fuel economy (miles/US gallons) in the USA and Canada. Adding an alcohol such as ethanol to gasoline at up to 5 to 10% may result in a minor increase in the volumetric fuel consumption. In a paper from the Canadian Renewable Fuels Association it is declared that although a 10 % ethanol blend contains about 3 % less energy than neat gasoline, the difference in energy content “is compensated by the fact that the combustion efficiency of the ethanol-blended fuel is increased” (Canadian Renewable Fuels Association, 2004).
This statement is consistent with findings by Laveskog and Egebäck, since their investigation (discussed in section 7.4) indicated that the lower energy content of the blended fuel was to a certain degree compensated by its higher combustion efficiency (Laveskog and Egebäck, 1999).
However, according to some other sources, e.g. a literature review prepared by the Orbital Engine Company for Environment Australia, there is a direct proportionality between fuel economy and the energy content of the ethanol-gasoline blend (Orbital Engine Company, 2002). In another report Orbital Engine Company has presented results from measurements of fuel consumption according to the Highway Fuel Economy Cycle (HWFET), as shown in Figure 7.15 (Orbital Engine Company 2004).
Page 66
Figure 7.15. The EPA Highway Fuel Economy Cycle.
The measurements of emission and fuel consumption were carried out on five vehicles of “newer” models and comprised tests in which both gasoline and ethanol were used in the same vehicle in order to generate comparative data. Some results of the emission measurements carried out by the Orbital Engine Company to study the efficiency of catalysts are presented in section 7.1, and in the following figures (7.16-7.18) the fuel consumption results are presented.
Page 67
02468
101214
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20Fu
el C
onsu
mpt
ion
[L/1
00 k
m]
6400 km80 000 km
Holden Ford Toyota Hyunday Subaru
FTP 75 Average Fuel Consumption for the Vehicle Fleet over milage. Gasoline vs E20
Figure 7.16. Average fuel consumption of the tested vehicles at 6,400 and 80 000 km when
driving according to the cycle city
0123456789
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Fuel
Con
sum
ptio
n [/1
00 k
m]
6400 km
80 000 km
Holden Ford Toyota Hyunday Subaru
Highway Average Fuel Consumption for the Vehicle Fleet over milage. Gasoline vs E20
Figure 7.17. Fuel consumption of the tested vehicles at 6,400 and 80 000 km when driving according to the city cycle
0
2
4
6
8
10
12
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20
Gas
olin
e
E20Fu
el C
onsu
mpt
ion
[l/10
0 km
]
6400 km80 000 km
Holden Ford Toyota Hyunday Subaru
Metro-Highway Average Fuel Consumption for the Vehicle Fleet over milage. Gasoline vs E20
Figure 7.18. Average fuel consumption of the tested vehicles at 6,400 and 80 000 km when driving according to the city cycle.
Page 68
A research project has been carried out on 15 vehicles of models from different years by a group at the Minnesota Centre for Automotive Research, Minnesota State University. Two blends of ethanol in gasoline, E10 and E30, were used during the test program, which was carried out to measure fuel consumption and emissions, and to analyse drivability characteristics, engine wear and material compatibility. The vehicles were tested on a chassis dynamometer according to both the hot 505 section of the standard test cycle and on the road when driven by owners of the cars. The fuel consumption and energy used per unit distance in the chassis dynamometer tests were matched to the distance driven in the on-road tests, based on the volumetric consumption. Oil samples were taken to analyse particles in the oil to evaluate whether accelerated wear of the engine had occurred. During the on-road tests the vehicles were driven by their owners (Bonnema et al., 2004).
The drivers were asked to fill in forms, the first of which concerned fuel consumption, while a second concerned maintenance, including changes to the car, such as changes of tyres or other parts which could have affected the results of the study. A third form concerned drivability. Consequently, the drivers of the cars during the field tests had to collect samples of oil for analysis and to record data concerning:
• maintenance and performance of the vehicles. • fuel consumption. • drivability complaints.
The results for fuel economy obtained in the Hot tests on the chassis dynamometer are summarized in Table 7.22.
Table 7.22. Fuel consumption and energy use when tested according to Hot 505 procedures (Bonnema et al., 2004). Vehicle
E10 l/10 km
E30 l/10 km
% Diff,
E10 MJ/10 km
E30 MJ/10 km
% Diff.
1996 Oldsmobile Acieva 1.01 1.19 +14.66 31.93 34.52 +8.11 1998 Dodge Caravan 1.09 1.24 +12.24 34.22 35.98 +5.16 1997 Chevrolet K3500 1.85 1.97 +6.14 58.33 57.37 -1.66 1994 Buick Regal 1.06 1.09 +2.96 33.28 31.64 -4.92 1997 Chevrolet K 1500 1.69 1.86 +8.99 53.26 54.01 +1.41 1998 Ford F-250 1.84 2.01 +8.74 57.81 58.42 +1.06 1997 Ford Taurus 1.28 1.29 +1.30 40.23 37.60 -6.54 1997 Ford F-150 1.65 1.85 +0.78 51.90 53.65 +3.38 1990 Chevrolet C1500 1.09 1.22 +10.42 34.46 35.50 +3.00 1992 Chevrolet K1500 1.51 1.68 +9.88 47.56 48.70 +2.39 1992 Geo Metro 0.62 0.69 +11.04 19.42 20.15 +3.73 + indicates an increase in fuel consumption or energy use when comparing E30 with E10. - indicates a reduction in fuel consumption and energy use when comparing E30 with E10.
It should be noted that the authors of the present report have not had access to appendices to the cited report, and hence have not been able to verify the interpretation of the data collected.
Page 69
However, the data in the above table indicate that there were differences between vehicles with respect to the effects of the ethanol blend in gasoline. Fuel consumption increased on a volumetric basis when E30 was used instead of E10, as expected, and the differences varied from less than 1% to over 12 %, which was less than expected. Concerning the energy used, the influence of using ethanol-gasoline blends with higher ethanol contents should be similar to their effect on fuel consumption, but as can be seen, the table shows a decrease for three of the vehicles. This may be due either to these vehicles being more energy efficient, or to uncertainties in the measurement of fuel consumption. The fact that vehicle studies have found a great diversity of responses to increasing ethanol content in terms of fuel consumption can be explained in a number of ways. However, a complicating factor is that the cited studies do not supply specific information on either the engine specifications or the fuels used for testing, although knowledge of these variables is essential for fully understanding the data. For example:
If a test compares a fuel with no ethanol and one with a 10% ethanol content, and it is run in an area where the base fuel used has a relatively low octane number, the lower energy content of the ethanol blend may be somewhat compensated by its higher octane rating, provided that the engines used have advanced ignition (knock control) systems according to Chandra Prakash (1988).
Carburetted vehicles may be affected by lean-mix problems if adjusted to a “low fuel consumption” setting, especially during acceleration and take-off from standstill.
Page 70
8. VAPOUR PRESSURE It is known that adding ethanol to gasoline raises the vapour pressure of the fuel. The chemical explanation for this is that gasoline consists mainly of hydrocarbons (straight, branched and aromatic hydrocarbons), which are nonpolar and have different boiling points. In contrast, the ethanol molecule (CH3CH2-OH) contains a hydroxyl group (-OH) which makes it polar. It is a well-known fact from solubility investigations that like dissolves like, i.e. polar solvents dissolve polar solutes and nonpolar solvents dissolve nonpolar solutes. Thus, introducing polar compounds like ethanol into gasoline (which is nonpolar) makes the gasoline blend more polar than neat gasoline, and increasingly polar as the ethanol content increases. This results in the vapour pressure of the ethanol-gasoline blend rising, since nonpolar compounds in the neat gasoline, with relatively low boiling points (and hence relatively high vapour pressure), will evaporate as the gasoline blend becomes more polar. In Figure 8.1 the Reid Vapour Pressure (RVP) (measured, by definition, at 100 ºF) is shown as a function of the percentage of ethanol blended with gasoline. The neat gasoline from 1997 (Furey and Jackson, 1977) had a higher initial vapour pressure than the gasoline from 2002 (Hsieh et al., 2002). The lightest chemical component of gasoline fuel in general is butane, which is removed to produce low RVP gasoline (Korotney, 1996). This indicates that the evaporative emissions from ethanol blended gasoline consist mainly of butane.
0
10
20
30
40
50
60
70
80
0 20 40 60 80 100
Volume % ethanol
RVP, kPa
Figure 8.1. Reid Vapour Pressure (at ~38 °C) shown as a function of the percentage of ethanol blended with gasoline (gFurey and Jackson, 1977; ♦DOE, 1991).
For both of the fuels shown in the figure the highest relative RVP was obtained at a percentage of ethanol in the neat gasoline of about 10%. Hence, there are strong indications that the maximum RVP will be obtained at a 5 to 10 percent ethanol content in gasoline, regardless of the neat gasoline fuels used. Decreasing the initial vapour pressure of the neat gasoline will reduce the absolute vapour pressure of a 10 percent ethanol blend. Furthermore, in Figure 8.1 the largest vapour pressure increase (a approximately 10 % increase in the RVP) is observed in the 0 to 5 percent ethanol interval. A compound in gasoline which has a major impact on the RVP is butane (Korotney, 1996).
Page 71
The compounds in the vapour phase from regular, mid and premium grade gasoline containing ethanol (3.25 to 9.65 wt%) have been investigated by Harley and Coulter-Burke (2000), in a headspace analysis in which they concluded that n-butane, n-pentane, 2-methylbutane and ethanol collectively accounted for more than 50% of the total headspace vapour mass at 38 ºC.
A large number of paper and reports have focused on the fact that blending ethanol in gasoline increases the vapour pressure, and this phenomenon has been investigated in a number of studies, especially in the USA, for example “Issues Associated with the Use of Higher Ethanol blends” (NREL 2002). In the early 1980s Furey (GM) reported that even a low level of alcohol in gasoline could have a high impact on the vapour pressure of the fuel (Furey 1985; 1986; 1990). A commonly quoted figure for the increase in RVP when blending base gasoline available on the US market with 10% ethanol is 1 psi (a little less than 7 kPa), see below concerning the “1 psi waiver”.
A report prepared for the Swedish Transport and Communications Research Board presented a limited investigation of two fuels (one vapour pressure-adjusted and the other unadjusted) used in three cars (see also section 7.4). The increases in vapour pressure found after adding 10 % ethanol were 5 kPa and 4.5 kPa, respectively.
In many countries, including European countries, RVP is commonly expressed in kPa units, while psi (pound per square inch) is used in the USA. To facilitate comparisons, a graph for converting psi to kPa and vice versa (based on a psi to kPa conversion factor of 6.895) and psi to kp/cm2 (another unit for measuring RVP used in some reports) is shown in Figure 8.2.
40
50
60
70
80
90
100
110
6 8 10 12 14 16
psi
kPa
0,41
0,51
0,61
0,71
0,81
0,91
1,01
1,11
kP/cm2
Figure 8.2. Graph for converting psi to kPa and kp/cm2.
An important issue in several countries related to the increase in vapour pressure caused by mixing gasoline with ethanol has been whether or not compensatory adjustments should be made to the vapour pressure of the base gasoline. If it is not adjusted the RVP may increase above regulated limits and may result in increased evaporative losses. Since many countries have regulations concerning RVP failing to meet the standards may even be illegal. In the EU, the RVP of gasoline is regulated by the European gasoline standard (EN 228).
Page 72
Since a high vapour pressure of the fuel may cause vehicle drivability problems and make hot starting impossible as a result of vapour lock, another relevant issue is driver acceptance of the fuel.
According to the literature some countries at least, such as the USA, Australia and Sweden, have decided to decrease the vapour pressure of the base gasoline used in alcohol blends in order to meet the existing standards/regulations.
8.1. RVP - USA
In the USA the vapour pressure of 10% ethanol-gasoline blends has been allowed to exceed the limits imposed for conventional gasoline by 1 psi (the “1 psi waiver”) Andress, 2000).
There has been ongoing debate in the USA about whether or not this waiver should be retained. The US EPA has been arguing that the waiver for ethanol-blended gasoline can be seen as a barrier hindering the broader introduction of reformulated gasoline. On the other hand, there has been pressure from the farmers producing ethanol and the Ethanol Fuel Association, since an increase in the use of ethanol, as a replacement for MTBE, would increase demand for ethanol. One factor to take into account, especially for the US EPA, is that the use of ethanol blended gasoline is recommended in CO non-attainment areas.
Documents from the California Air Resources Board (CARB) (CARB, 1998) show that replacing gasoline with ethanol may clearly reduce CO emissions, even if the gasoline is not adjusted to comply with RVP requirements (i.e. the 1 psi waiver is applied). Thus, adding ethanol to gasoline has provided a means to meet CO levels required by the air quality standards in many of the current, so-called CO non-attainment areas. However, these documents also show that adding ethanol to gasoline without adjusting the RVP leads to increases in the emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx), and in the fuel’s ozone-forming potential. Since both VOC and NOx are important emissions in the formation of tropospheric ozone the 1psi waiver has not been applied to mixtures of ethanol in reformulated gasoline (RFG), which is primarily intended for use in ozone non-attainment areas to avoid increased formation of ozone.
The effect of this waiver is discussed in a study released by the EPA that provided part of the rationale for introducing reformulated gasoline (RFG), i.e. gasoline containing an oxygenate, which at the time could be either MTBE or ethanol (US EPA, 1993). It was proposed that a renewable oxygenate should be used, and one of the most controversial questions addressed when the RFG rule was drafted was how ethanol/gasoline blends should be treated. The EPA argued that the base gasoline had to be adjusted to ensure that the vapour pressure met the standards. However, the EPA had to accept that adjusting the RVP could lead to cost penalties, inter alia, for the ethanol blended fuel. An argument propounded in comments sent to the EPA was that ethanol would be excluded from the market without a waiver. The opinion among the rule makers within the EPA was that ethanol is cheaper than MTBE per gallon and that this cost difference could well compensate for the costs of adjusting the RVP, which are minor compared to the cost of adding oxygen via oxygenate additions.
In the cited paper (US EPA, 1993) the EPA also discussed the detrimental effect on emissions of granting the waiver of 1 psi RVP, since blending ethanol in gasoline will increase the vapour pressure of the fuel, and hence increase VOC emissions. Two letters from EPA staff claim that a fuel that met RFG requirements in every respect except its RVP and had an RVP of 1 psi over the limit would increase VOC emissions by about 20 % relative to a baseline gasoline.
Page 73
Furthermore, the EPA argued at that time that ethanol blends with a 1 psi waiver would have an advantage over RFG and thus might dominate the market (US EPA, 1993).
The estimated reduction in VOC emissions likely to follow the introduction of RFG based on unblended gasoline is estimated to be 11 %, see Table 8.1. The reduction will be less if ethanol blended gasoline is used, and considerably less if RVP-adjusted gasoline is not used as a base according to the EPA estimations. Consequently, the reduction in VOC emissions will diminish as the ethanol market share increases, as can be seen in Table 8.1.
Table 8.1. Losses of “In-Use” VOC Emission Control as a Result of the Ethanol Waiver for RFG*
Ethanol Market Share (%) 0 8 24 30 35
% VOC Reduction Due to MTBE Share
11 10.1 8.4 7.7 7.2
% VOC Reduction Due to Ethanol Share (with distillation)
0 -1.0 -3.1 -3.9 -4.6
% VOC Due to Commingling 0 -1.2** -2.4 -2.4 -2.4 Total % VOC Reduction 11 7.9 2.9 1.4 0.2 Percentage Change from 100% MTBE Baseline
N/A 28 74 87 98
* Emission percentage change input values shown are based on those calculated in the letter from Chester France to Dr. Gary Whitten. Memorandum 6 from Paul A. Machiele, Fuel Studies and Standards Branch, to Richard D. Wilson, Director, Office of Mobile Sources, "Update of the Relative Ozone Reactivity of Reformulated Gasoline Blends," June 11, 1993.
** Commingling, assuming half of that at higher market shares based on analysis (US EPA, 1993).
A paper from the US Energy Information Administration section (EIA, 2002) of the US Department of Energy (DOE) describes, inter alia, the effect of adjusting the RVP of base gasoline intended for blending with ethanol. A primary feature it displays is that there is a relationship between the RVP of the base gasoline, and the magnitude of the impact on the RVP when adding ethanol to the base gasoline is shown in Table 8.2
Table 8.2. RVP effect of blending ethanol to the base gasoline. Finished Gasoline RVP
Requirement Approximate RVP Increase when Ethanol is Added to
Make a 10% Blend
Base Gasoline RVP Adjustment Needed if 1
Pound Waiver Not Allowed 9.0 1.0 (1.1) 7.8 1.2 (1.3) 7.0 1.3 (1.4)
Sources: William J. Piel, “Oxygenate Flexibility for Future Fuels,” Acro Chemical Company, paper presented at the National Conference on Reformulated Gasoline and Clean Air Act Implementation, Information Resources, Inc. Washington, DC, October 1991, American Petroleum Institute, Alcohols and Ethers, Publication 4261
The paper cited above (EIA, 2002) discusses the energy losses from the gasoline pool due to removing C4 and C5 hydrocarbons from it in order to meet the RVP requirements of gasoline without the 1-psi waiver. The study that the paper was based upon was initiated by discussions about the possible removal of the 1-psi waiver following a request by Senator Bingaman
Page 74
(Chairman of the Senate Committee on Energy and National Resources) presented in a separate paper (Office of Oil and Gas of the Energy Information, 2002).
It is interesting to note that an adjustment of the base gasoline intended for use with ethanol blends in order to keep the RVP under the required limits may reduce the energy content of the gasoline pool to a larger degree than the energy supplied by the added ethanol (EIA, Energy Information Administration, 2002). However, the magnitude of the reduction in energy content depends on the RVP requirement and the gasoline used for blending. In the USA, especially California, where the maximum RVP allowed is 7.0 psi (48.3 kPa), adjustment of the gasoline to be used for blending with 10 % ethanol will result in a 2.8 % reduction in its energy content. In contrast, in areas of the USA where the maximum RVP is 9 psi (62.1 kPa) the result of adding 10 % ethanol to RVP adjusted gasoline will be a 4.5 % increase in the energy content. Not adjusting the base gasoline intended for use in 10 % ethanol blends will result in a 5.1 % increase in the energy of the gasoline pool if there is a 7.0 psi RVP requirement and a 7.5 % increase if there is a psi 9.0 RVP requirement.
These two examples could be used as models for calculating the effect of adjusting the base gasoline for blending, in energy terms, when deciding whether it should be adjusted or not. However, it should be emphasised that the components (mostly butane) removed from the base gasoline when adjusting the RVP will generally be used for other purposes and not wasted. The increase in evaporated hydrocarbon emissions that will occur if the RVP is not adjusted should be analyzed and discussed when deciding whether these polluting emissions will be unacceptably high (see table below).
Volume and Energy Effects of Adjusting RVP Prior to Adding Ethanol Volume Change due to Adding
Ethanol to Make a 10% Ethanol Blend
Energy Change due to Adding Ethanol to Make a 10% Ethanol
Blend
RVP
With RVP Waiver
Without RVP Waiver
With RVP Waiver
Without RVP Waiver
9.0 11.1% 7.5% 7.5% 4.5% 7.8 10.3% 2.2% 6.8% -0.2% 7.0 8.3% -0.9% 5.1% -2.8%
A paper published by the US EPA (Korotney, 1996) considers RVP-related characteristics associated with three different gasoline blends: “Low RVP gasoline”, “Reformulated gasoline (RFG)” and “Conventional gasoline”. Low RVP gasoline is produced from conventional gasoline by removing butane (EPA 1996), while RFG is “blended to burn cleaner and reduce smog-forming and toxic pollutants” (Virginia Department of Environmental Quality 2005). Conventional gasoline is a mixture of compounds, called hydrocarbons, refined from crude petroleum, plus small amounts of a few additives (Utah Petroleum Association, 2004). Conventional gasoline is also called “Commercial gasoline” and in certain areas of the USA will be blended with ethanol (commonly to 10 %).
Korotney addresses implications of the facts that the only compound removed from conventional gasoline is butane and that low RVP gasoline is produced solely to meet the RVP requirements of 6.8 psi to 8.1 psi, with typical values of 7.0 to 7.2 psi.Since the intentions when designing reformulated gasoline were not only to meet the RVP requirements, but also to reduce emissions
Page 75
of toxic substances, his conclusions concerning low RVP gasoline, compared with conventional gasoline are inter alia that:
• Low RVP gasoline will reduce the evaporative emissions. • The primary emission benefits (VOC) of low RVP gasoline come from reductions in
evaporative emissions. • Exhaust emission reduction is very small or nonexistent. • Low RVP gasoline will have little or no effect on NOx. • Evaporative emissions of VOC tend to be less reactive (i.e. produce less ozone) per gram
than exhaust VOC. • Since nitrogen oxides (NOx) are combustion products, they will not be found in
evaporative emissions, so using low RVP gasoline should have little or no effect on NOx emissions. However, empirical evidence indicates that use of low RVP gasoline may actually increase the NOX emissions by 1 %.
• Low RVP gasoline will not reduce carbon monoxide (CO) emissions, and may in fact increase them slightly. RFG gasoline, on the other hand, will affect CO emissions since they are influenced by the oxygen content of the fuel and not the RVP.
• Since ozone is formed in the atmosphere from complex reactions involving NOx, VOC and CO, reducing the RVP will have less effect on its levels than using RFG, which will have also affect NOx and CO emissions.
Another paper released by the EPA (US EPA, 1996) represents a response to a letter from the American Petroleum Institute (API) is presented (US EPA, 1996)The director of the API, C.J. Krambuhl, opposed statements of the EPA (Korotney) in their paper about low RVP gasoline. The main argument by Krambuhl was that the low RVP gasoline is more cost-effective than the reformulated gasoline. In a short answer to the API, the EPA’s Fuels and Energy Division Director, C.N. Freed, notes that “The modest reductions in NOx for Phase I, RFG, and the more substantial reductions in NOx for Phase II, RFG, provide a means for immediately reducing ozone without waiting for fleet turnover”. He also invited the API to a meeting with the EPA in order to clarify the latter’s position. In a report (US EPA, 1999) it is stated that “Beginning on January 1, 2000, the Phase II complex model standards at 40 CFR 80.41(e) and (f) will apply to all RFG in the gasoline distribution system”. 8.2. RVP - Brazil
Brazil introduced ethanol as a neat fuel for spark ignition engines more than 20 years ago. The Brazilians have also tried blending ethanol to different levels with gasoline since then. The introduction of ethanol was due more to rural and agricultural politics than to environmental concerns. Hence, the number of relevant emissions tests etc. they carried out was limited. The use of ethanol as a vehicle fuel in Brazil has varied over the years, mainly because of variations in the production capacity and changes in the taxation system. Today, a number of FFVs and vehicles optimised for running on neat ethanol are being used in Brazil. In addition, all marketed gasoline is blended with approximately 20 % ethanol. Furthermore, there is no tax reduction for ethanol in Brazil today, because its low production costs (reduced incrementally over the past 20 years) allow it to compete on the fuel market without any such advantages.
Nevertheless, very few tests have been done in Brazil regarding the environmental effects of using ethanol as a vehicle fuel. Ethanol is regarded as an environmentally friendly fuel with low CO2 emissions, and no need for further debate is recognised. The potential problems associated with increased vapour pressure due to adding ethanol to gasoline, including increased
Page 76
evaporative losses, do not apply in Brazil since they use either neat ethanol (with very low RVP) or at least 20 % ethanol blended in gasoline; a level at which the increased vapour pressure has declined more or less back to the original RVP of the base gasoline (Alfred Szwarc, personal communication, 2004).
8.3. RVP - Europe
In Europe the vapour pressure of gasoline is restricted to:
• A minimum of 45 kPa and a maximum of 60 kPa in summertime. • In countries with Arctic and sub-Arctic climates, such as Sweden, the RVP must be at
least 45 kPa and no more than 70 kPa in summertime*.
In Sweden not many investigations have been carried out on the relationship between ethanol blends in gasoline, increased vapour pressure and increased evaporative emissions. However, one such study is described in the report, mentioned earlier, prepared for the Swedish Transport and Communications Research Board (KFB) by Laveskog and Egebäck (1998; see section 7.4).
In another, the vapour pressure and evaporative emissions from E85 (85 % ethanol and 15 % gasoline), E10 and reference gasoline were studied in a project carried out by Lu-Karlsson (1999) at the MTC (Motortestcenter of Sweden). Using a simulated Sealed Housing for Evaporative Determination (SHED) test method, the total amounts of hydrocarbons (HC) that evaporated were quantified and the composition of the evaporative emissions was chemically characterized. The evaporative emission components detected were ethanol, benzene, toluene, C4-C6, alkanes and olefins. The E10 mixture gave the highest HC evaporative emissions. Compared to gasoline, the E10 gave elevated C4 – C6 alkanes and olefin emissions, but reduced aromatic emissions. Compared to the reference gasoline, the base gasoline with a higher vapour pressure gave significantly higher C4 – C6 alkane and alkene emissions.
At the European level (JCR – ISPRA), in 2004 Eucar and Concawe carried out a joint investigation of evaporative losses and other phenomena associated with blending ethanol in gasoline. The objectives of the project were:
• To clarify the effect of fuel vapour pressure on volatility and evaporative emissions from modern cars equipped with canisters, representative of the recent European fleet.
• To assess the effect of ethanol blending on fuel properties and evaporative emissions (quantitative and qualitative).
• To assess the impact of the cars’ fuel system technology on the evaporative emissions (canister aging, metal/plastic tanks).
• To provide a firm technical basis for debates on gasoline vapour pressure limits in relation to ethanol blending for the Fuels Directive Review.
The tests were to be carried out on two base gasolines (one vapour pressure-adjusted and one unadjusted), and ethanol blends (with 5 and 10 % ethanol contents) of these fuels were to be examined. However, no official report from the project has been presented as yet.
* During wintertime in Finland, Norway and Sweden the RVP ranges from 50 to 95 kPa.
Page 77
8.4. RVP - Australia
According to the literature studied there is a clear preference for mixing ethanol in gasoline in Australia. The main issue addressed by the authors involved has been the percentage of ethanol that should be allowed to be blended in the fuel. In a paper from Environment Australia discussing this issue (Environment Australia, 2002) it is pointed out that ethanol-gasoline blends with10 % ethanol content are already available on the market, while the process to set environmental standard for gasoline should allow only 7.8 % ethanol in gasoline (i.e. 2.7 % oxygen by weight instead of 3.5). Furthermore, ethanol blends should have to meet the Reid Vapour Pressure requirements, which according to the standards should be <62 kPa in the area around Sydney, <67 kPa in Perth and <76 kPa in Queensland during the summer months according to Hellens (2002) of BP Australia.
8.5. Theoretical Discussion on Vapour Pressure Using Raoult’s Law
For liquid-liquid solutions where both components – in this case gasoline (gas) and ethanol (eth) – are volatile a modified Raoult’s law applies.
Ptotal = Pgas + Peth = χgasP0gas + χetP0
eth ; χgas+χeth=1
Where Ptotal represents the total vapour pressure of a solution containing gasoline and ethanol, χgas and χeth are the mole fractions of gasoline and ethanol, respectively, and P0
gas and P0eth are
the pressures of the “pure” solutions. As gasoline is a mixture of chemical compounds and not a pure compound, only a theoretical discussion can be applied. However, in Figure 8.3 the vapour pressure of a gasoline-ethanol fuel blend is shown as a function of the ethanol mole fraction (χeth), based on the same primary data as used in Figure 8.1. The ethanol mole fraction was calculated using a “theoretical” calculated mean molecular weight of gasoline. The theoretical mole fraction of gasoline in the ethanol-gasoline blend was calculated using information on the percentage (by weight) of carbon and hydrogen in the gasoline. The estimated weight percentages used for carbon and hydrogen in gasoline are 87 and 13, respectively, accordingly to Hsieh et al. (2002). Using these values as input data a theoretical molecular formula of C15H26 can be calculated for gasoline, consisting of ≈87 percent (w/w) carbon and ≈13 percent (w/w) hydrogen. In Figure 8.3 a positive deviation from Raoult’s law can be seen, which can be attributed to the ethanol and gasoline interactions in the blend being weaker than the interactions among the molecules as neat liquids. Molecules in the blend have a higher tendency to reside in the gas phase, thus increasing the vapour pressure and leading to a positive deviation from Raoult’s law, as shown in Figure 8.3.
Page 78
Vapour pressure, Raults law
01020304050607080
0 0.2 0.4 0.6 0.8 1
Mole fraction of ethanol
RVP, kPa
Figure 8.3. Reid Vapour Pressure (gFurey and Jackson, 1977; ♦DOE, 1991) as a function of the mole fraction of ethanol (χeth) blended in gasoline. X Ethanol RVP, Δ gasoline RVP, * gasoline/ethanol blend of ideal solution.
8.6. Findings • When ethanol is added to gasoline the vapour pressure of the resulting blend increases. The
highest RVP is reached at a blending with approximately 10 % ethanol. Increasing the ethanol content above 10 % reduces the RVP, and at levels of 20 to 40 % ethanol (depending on the specification of the gasoline used) the RVP of the blend returns to the original level of the gasoline. Further increases in ethanol content will further decrease the RVP of the blend to levels below the original RVP of the gasoline used.
• Increased RVP may increase VOC emissions, depending on the type of evaporative emission control system used. However, no direct correlations between the gasoline vapour pressure and the exhaust VOC emissions from vehicles have been found.
• RVP-adjusted gasoline that is used for blending with ethanol, but still fulfils the RVP requirements set by EN 228 specifications, will have a lower energy content than gasoline that is not so adjusted
• Increased vapour pressure of a fuel may affect the drivability of the vehicle at high ambient temperatures, i.e. vapour lock may occur. It may also affect hot engine start ability.
• There is not much data from Swedish or European investigations on the effects of increased fuel vapour pressure on evaporative and tailpipe emissions. This issue is currently being investigated in an EU project, but no data or reports arising from it have been published to date.
• It is difficult to apply data from USA directly to Swedish or European conditions, since the gasoline used in the USA is quite different from Swedish/European gasoline standards. Gasoline standards applied in the USA are designed to solve problems such as poor air quality in city centres and the formation of tropospheric ozone, which are not always prioritised in Europe. Furthermore, the data from the USA can be mutually contradictory.
• There are very few data on emissions from Brazil regarding vehicles running on neat ethanol or ethanol gasoline blends. However, since the lowest ethanol content of the Brazilian fuel blends is 20%, the evaporative emissions from the vehicles are limited.
Page 79
9. RISK FOR EXPLOSIONS AT LOW AMBIENT TEMPERATURES McArragher (1996) discussed the minimum Reid Vapour Pressure required to ensure that the upper flammability limit of gasoline vapour is exceeded; a critically important safety issue (McArragher, 1996). This means that the head space in a tank should be saturated with gasoline vapour at a greater partial pressure than the upper flammability limit for a gasoline-air mixture, thus avoiding the risk for explosion. However, at low RVP and low ambient temperatures there is a risk that the headspace in a tank will be saturated with gasoline vapour which is under the upper flammability limit of the gasoline-air mixture, which is then an explosive chemical mixture. Blending up to approximately 10 % ethanol in the gasoline increases the initial RVP of the neat gasoline (Figure 8.1), suggesting that it should reduce the risk for a flammable mixture forming. If the ethanol content is increased above approximately 10 % the RVP of the gasoline/ethanol blend is lowered (Figure 8.1). At approximately 25 % ethanol, the gasoline-ethanol blend has approximately the same RVP as the neat gasoline. This means that use of ethanol contents higher than approximately 25 % will increase the risk that vapour will form with pressures under the upper flammability limit. According to the Swedish Rescue Services Agency (SRSA, 2004) there is no difference between gasoline and ethanol-blended gasoline from a legal perspective in terms of the risk for flammability or explosion. However, a concern raised by the SRSA is that ethanol can adversely affect the foam used by fire fighters, although ethanol-resistant foam is available. Thus, this potential problem can be overcome by informing local fire stations about the presence and locations of ethanol-blended gasoline filling stations.
Page 80
10. LIFE CYCLE ANALYSIS (LCA) OF GASOLINE AND ETHANOL BLENDS Life Cycle Analysis is a tool for analyzing and assessing environmental consequences of human actions, originally used to address product-related environmental issues. In LCA a product is followed from “cradle to grave” i.e. from raw material acquisition, through production, use and waste disposal. By assessing all of the industrial processes associated with manufacturing a given product, sub-optimization can be avoided, with respect to issues such as whether a raw material can be replaced with a less toxic one without increasing the total environmental impact due to changes in transportation distances or modes, and whether production of the new raw material (or substitution of a product with a similar one) will generate more or less toxic emissions
The ISO standard for LCA (ISO 14040, 1997) defines it as a “technique for assessing the environmental aspects and potential impacts associated with a product”, by:
• Compiling an inventory of relevant inputs and outputs of its production system. • Evaluating the potential impacts associated with those inputs and outputs. • Interpreting the results of the inventory and impact assessment phases in relation to the
objective of the study.
LCA can be used to assess and compare, in a “cradle to grave perspective”, effects of using different vehicle fuels, such as gasoline, bio ethanol and bio ethanol-blended gasoline. The results may elucidate the “total” effects on the climate, environment and health of replacing gasoline to varying degrees by bio ethanol. However, when using LCA for assessment/comparison of different situations it is important to apply the same system boundary and framework conditions consistently. Otherwise, the LCA will not give reliable answers to the questions posed. For example, in response to a request by the Swedish Alternative Fuel Committee, Magnus Blinge of Chalmers University of Technology, Gothenburg (Blinge, 1996) compared about 20 different LCAs related to conventional and alternative vehicle fuels. One of Blinge’s main conclusions was that it was not possible to make a good comparison between these LCAs or to extract relevant average emission data concerning production, vehicle use etc. from them, largely because of small differences between them in terms of parameters such as the test vehicles (age and engine/vehicle configuration) and the test cycles used.
10.1. LCA in the Context of This Project
The main purposes of the literature study related to LCAs within the BIFF-project were to search for, and examine, LCAs that included assessments of as many as possible of the following:
• The environmental and health effects of emissions from the use of neat gasoline and various ethanol-gasoline blends, ranging from 5 to approximately 20 % ethanol.
• Both vapour-pressure adjusted gasoline (i.e. gasoline fulfilling RVP requirements even after blending with ethanol) and unadjusted gasoline (with which blends would not meet such requirements).
• Emissions not only of carbon dioxide and/or other greenhouse gases, but also of regulated emissions and, as far as possible, other unregulated contituents.
Page 81
• Potential differences in the emissions associated with various ethanol blending levels in different types of gasoline (RVP-adjusted and unadjusted).
• Changes in emissions from sensitive “emission points” from harbour/refinery to vehicle/tailpipe due to use of ethanol-gasoline blends with various ethanol contents and, if possible, identification of the best point in the chain for blending ethanol into gasoline, to minimise evaporative losses.
• If (and if so how) switching from the use of RVP-adjusted gasoline to unadjusted gasoline (allowing increases in vapour pressure) in gasoline-ethanol blends would affect the overall climatic, environmental and health impact.
A further objective of the work was to find out if LCAs, such as those mentioned above, carried out in the USA and other countries could provide a reasonable basis for predicting life-cycle changes in emissions that would follow the use of 5 to 20 % ethanol blends with gasoline, and fuels for use in Otto engines, and their impact (especially on the environment and health), under Swedish or European conditions. However, it was (and is) essential to remember that basing predictions on LCAs is likely to be difficult, or even impossible, unless the system boundary and framework conditions are very similar.
10.2. LCA Studies for Ethanol in Neat Form or Blended with Gasoline
USA
The literature survey revealed that many LCAs have been carried out on the production and use of ethanol, mostly in the USA, under typical American conditions, e.g.:
• The raw materials for the production in the USA are often corn or corn residues. • The vehicle parameters used in the LCA calculations are generally typical for
engines/vehicles sold in the USA 5 to 10 years ago. • The conventional fuel used in the comparisons is generally common US gasoline, which
is not the same as European and less than that Swedish gasoline. In addition, the gasoline quality differs between regions/states in the USA and the US authorities have established special gasoline qualities for areas with special air quality problems, the so-called non-attainment areas (with respect to CO or tropospheric ozone). This means gasoline qualities with a minimum level of oxygen or a minimum level of added oxygenate (MTBE or ethanol), gasoline with a maximum level of vapour pressure (low vapour pressure gasoline, LWG) or gasoline with a maximum vapour pressure and low level of specific compounds, such as benzene and aromatics, reformulated gasoline (RFG).
Examples of such LCAs include:
• Fuel-Cycle Fossil Energy Use and Greenhouse Gas Emissions of Fuel Ethanol Produced from U.S. Midwest Corn, Michel young, Christopher Saricks and May Wu, Argonne National Laboratory, US, 1997 (Young et al., 1997).
• Effects of Fuel Ethanol Use on Fuel-Cycle Energy and Greenhouse Gas Emissions, M Wang, C Saricks and D Santini, Argonne National Laboratory, USA (Wang et al., 1999).
However, since these LCAs were based on conditions specific for the USA there are various difficulties in using them as a basis for predictions related to Swedish and/or European conditions other than merely giving hints about likely results.
Page 82
Furthermore, the LCAs that have been found mostly focused on emissions of carbon dioxide, and sometimes other greenhouse gases, but LCAs seldom consider emissions of regulated or other non-regulated constituents.
Europe
For European conditions General Motors, together with Argone National Laboratory, published a report entitled “Well-to-Wheel Energy use and Green House Gas Emissions of Advanced Fuel/Vehicle System – A European Study” The work was carried out with BP, ExxonMobil, Shell and TotalFinal Elf as active participants, and is a complement to a similar study for North American conditions published in 2001 (GM 2001). However, as can be seen from the title this LCA-study only covers greenhouse gases and energy use.
Another LCA related to European conditions was jointly undertaken by CONCAWE, EUCAR and the EU-Commissions/Joint Research Centre, as reported in “Well-to-Wheel Analysis of Future Automotive Fuels and Power Trains in the European Context” (Concawe 2004). This report also focuses on the emissions of greenhouse gases, as do two other European LCAs on bio fuels/ethanol. One carried out by Patyk and Reinhardt, of the Institut für Energie und Umweltforschung, Heidelberg, Germany, (Patyk and Reinhardt, 2002), entitled “Life Cycle Analysis of Bio Fuels for Transportation used in Fuel Cells and Conventional Technologies under European conditions”. The other, carried out by the French authority for environment and energy, ADEME, together with Ecobilan, PricewaterhouseCoopers and DIREM, was called “Energy and Greenhouse Gas Balances of Bio Fuels Production Chains in France, and was published in December 2002 (ADEME, 2002).
Sweden
Several LCAs have been carried out on the production and use of alternative vehicle fuels under Swedish conditions, focusing on (or at least including) ethanol. In 1997, Magnus Blinge, of Chalmers University of Technology, Gothenburg, carried out an LCA on different alternative fuels following a request from the Swedish Transportation Research Board (Blinge et al., 1997). This LCA, despite being relatively old, and not based on the latest data, information and technology, still seems to be one of the best. It also covers non-regulated emissions. However, in addition to being old, the results are primarily valid for Swedish conditions and not applicable to the rest of Europe.
Another Swedish LCA that is specifically related to Swedish conditions is Agro Ethanol’s LCA on the annual production of 50 000 m3 grain-based ethanol at the Agroetanol AB production plant outside Norrköping. However, this LCA is focused solely on emissions of greenhouse gases.
Other countries
Two LCAs from countries outside Europe and the US are:
• Comparison of Transport fuels carried out by Beer and co-workers, the Australian Greenhouse Office, The University of Melbourne (Beer et al., 2002).
• Assessment of Greenhouse Gas Emissions in the Production and Use of Ethanol in Brazil, Government of the state of Sao Paulo, carried out by Isaias de Carvalho and co-workers. (I Carvalho et al., 2004).
Page 83
Both of these LCAs are concerned with emissions of greenhouse gases and energy efficiency.
In addition, of course, LCAs have been carried out in other parts of the world, including China (see below), India and Canada, but these have also focused mainly on emissions of greenhouse gases with clear country-specific framework conditions, largely concerning the raw material.
10.3. Discussion
LCAs on the production, distribution and use of a vehicle fuel such as ethanol is often carried out with country-specific framework conditions such as the sources and nature of the raw material used to produce the fuel.
In most of the LCAs carried out to date on ethanol, “neat” ethanol for FFVs, 85 % ethanol and 15 % gasoline (E85), or ethanol-gasoline blends with low alcohol contents (5 % or occasionally 10 %; E5 or E10), are compared with neat gasoline. LCAs comparing blends with higher ethanol contents, up to 20 or 30 % for example, are scarce.
Concerning the parameters studied in LCAs on the production, distribution and use of alternative fuels/ethanol most have mainly focused on their climatic impact, especially emissions of carbon dioxide and, occasionally, emissions of other greenhouse gases.
LCAs that consider regulated emissions are not common. The investigation by Blinge and co-workers. (Blinge et al. 1997) is an exception, as is the “Economics, Environment and Energy Life Cycle Assessment of Automobiles Fueled by Bio-ethanol Blends in China”, study by Zhiyuan Hu and coworkers of Shanghai Jiao Tong University, China (Zhiyuan et al., 2004).
Furthermore, there have been few studies related to non-regulated emissions, and they are difficult to find.
To summarize:
• It is difficult to find LCAs that meet the criteria sought here. • It is difficult to draw general conclusions concerning specific emissions due to the
production, distribution and use of ethanol as vehicle fuels from a number of different LCAs because of differences in their system boundaries and framework conditions.
• It is difficult to use LCAs that have been published to date to predict general conditions for situations that were not foreseen, or considered, when they were carried out.
Although it is difficult to find the kind of LCA sought for and described in chapter 4.9.2, there is at least one example of an LCA in which different types of gasoline were examined that could be used as a procedural model for LCAs considering ethanol blends of RVP-adjusted and unadjusted gasoline. The study was performed by Teresa Mata and co-workers of the University of Porto, Portugal (Mata et al., 2003).
In the cited LCA, a life cycle analysis or assessment compared the potential environmental impact of various gasoline blends that all met the same octane and vapour pressure specifications. The system boundaries were set to include the refinery process, but exclude the fuels’ use in a vehicle. For the chain from refinery to refueling of the vehicle seven stages were defined and emission factors were calculated. Several types of gasoline that differed in their specifications, but fulfilled standard octane number and RVP requirements, were compared in terms of their potential environmental impact due to hydrocarbon emissions. The results of the
Page 84
study showed that since the blending components such as alkylate, cracked gasoline and reformate have different octane numbers and vapour pressures, as well as differing in their potential environmental impact, some gasoline blends are less detrimental for the environment than others.
10.4. Findings
LCAs are difficult to find, worldwide or in Europe/Sweden that:
• Have relevant framework conditions (modern engine systems, relevant fuel specifications etc).
• Consider the emissions not only of greenhouse gases but also of regulated and other non-regulated constituents.
• Compare regulated and non-regulated emissions (tailpipe emissions and evaporative emissions) from a well-to-wheel perspective and their impact on the environment and health from the production, distribution and use of gasoline with blends of RVP-adjusted and unadjusted gasoline with 5 to 20 % ethanol.
A number of LCA:s have been carried out (mainly but not solely in the USA), but they have applied more or less country-specific framework conditions with respect to the raw material used for the ethanol production and specific gasoline specifications. They have also often focused (as have most LCAs on the production, distribution and use of other alternative fuels) on the emissions of greenhouse gases. From a European or Swedish perspective, LCAs carried out in the USA or other parts of the world probably differ too much in their framework conditions to provide a relevant basis for predictions under European/Swedish conditions.
To obtain information concerning whether (and if so, how) evaporative emissions and tailpipe emissions might differ, from a well-to-wheel perspective, it seems necessary to carry out a new LCA. Such an LCA could be structured similarly to that of Mata and co-workers (Mata et al. 2003), but with specific Swedish framework conditions.
Such an LCA should focus on:
• Ethanol blended gasoline with ethanol contents in the 5 to 20 % range. • Gasoline fulfilling RVP conditions in Europe/Sweden. • Gasoline not fulfilling the RVP conditions. This implies accepting an increased RVP. • Besides carbon dioxide, other greenhouse gases and both regulated and non-regulated
emissions should be measured.
If possible the LCA should include some kind of evaluation concerning the extent to which different types of canisters could reduce the evaporative emissions from the vehicle and the extent to which they would reduce the total volume of emissions.
Page 85
11. CONCLUSIONS AND RECOMMENDATIONS Please note that conclusions from the literature study are written in regular font (Times New Roman) and recommendations by the authors of the present report are written in italic. American car manufacturers have agreed to accept the use of blends with up to 10 % ethanol in gasoline in their vehicles, without changing the warranty conditions. Many car manufacturers in Europe and Japan sell vehicles in North America. Therefore, the design of currently available on the European market, including Sweden, may allow the use of blends with at least 10 % ethanol in gasoline. A conclusion which can be drawn from the literature study is that newer models of vehicles are more tolerant to changes in the composition of fuels such as a blend of 10 % ethanol in gasoline. One problem that may apply to older vehicles is that alcohol tends to react with rubber. Owners of such cars should refrain from using alcohol blended gasoline. Many authors of papers dealing with alcohol fuels claim that the main cause of reported problems of using alcohols, especially methanol, as a fuel for vehicles is that they have often been used in older cars. Further studies of the vehicle fleet in Sweden may be needed to generate information about the implications of using gasoline blends with up to 10 % ethanol for older cars which may be less tolerant to them than newer models.
It is difficult to apply data from investigations carried out in other countries directly to Swedish conditions since many variables differ from country to country, especially in terms of the fleet of vehicles, the fuels, emission regulations and certain other factors. In addition, some investigations evaluated in the present report have given contradictory results. However, updated exhaust emissions (of both regulated and unregulated compounds) from neat gasoline and ethanol gasoline blends should be characterized as described in the present report in tests at both ambient temperature of 20 ºC (in accordance with current certification procedures) and lower temperatures, e.g. -20 ºC. Start ability and drivability at low ambient temperatures such as -20 ºC are important variables to investigate due to the harshness of Swedish winters. Methods for sampling and analysing exhaust emissions have not been adequately developed for alternative fuels in general since traditional sampling and analysis methods were developed for characterizing emissions from traditional fuels such as gasoline and diesel oil. There is a need to develop and update methods for sampling and analysing vehicle exhaust emissions generated from the combustion of alternative fuels. The percentage of ethanol in gasoline blends evaluated should primarily be in the range of 10 % as this could be the first upper target. Higher than 10 % contents of ethanol in gasoline are expected to be of more importance after the year 2010. Investigations and evaluations conducted for the American Lung Association of Minnesota discussed in the present report have shown that the sulphur content of the fuel has a considerable impact on both regulated and unregulated emissions. Therefore, data on emissions generated using fuels with relatively high sulphur contents cannot be directly applied to Swedish
Page 86
conditions, since Swedish gasoline standards have allowed only 10 ppm sulphur since January 2005. There is a need for updated emission factors for both regulated and unregulated exhaust emissions from “modern” vehicles running on neat gasoline and ethanol-blended gasoline. Besides measurements obtained following standard procedures, tests at low ambient temperatures (-20 °C) should also be included. Emission factors are needed for emission inventories, which provide a basis for evaluating health and environmental effects. Local fire stations should be informed about the presence and location of ethanol blended gasoline filling stations to ensure the use of ethanol-resistant foam in the case of fire. This is also an important issue to consider if fires occur in vehicles running on these fuels, since their fuel tanks will contain ethanol/gasoline blends. 11.1. Fuel Reid Vapour Pressure
When an alcohol is blended with gasoline the vapour pressure of the blended fuel will increase (and considerably more for methanol than for ethanol). If ethanol is added, the RVP increases most rapidly with further additions in the ethanol content interval from 0 to 5 %, and it peaks at a blending level of approximately 10 % ethanol. The RVP then declines with further increases in the ethanol content, and at a level of 20 to 40 % ethanol (depending on the specification of the neat gasoline used) the RVP of the blend returns to the original level of the base gasoline. A further increase in ethanol content will then reduce the RVP of the blend to levels lower than that of the gasoline used.
Increasing RVP may increase the VOC emissions, depending on the type of evaporative emission control system used. There is a need for updated emission factors for evaporative emissions from “modern” vehicles running on ethanol mixed with gasoline (5 - 10 %), comparing emissions from the use of both RVP-adjusted and non RVP-adjusted gasoline. In addition to measurements of evaporative emissions according to the standard method, emitted hydrocarbons should be analysed to generate data for use in further evaluations. With such data it will be possible to: (i) evaluate whether the evaporative emission standards are met and (ii) to evaluate whether the emitted hydrocarbons will have an impact on the environment and health in Sweden.
Increasing the RVP of a fuel may affect the drivability of the vehicle at high ambient temperatures, since it may cause vapour lock and may also affect hot engine starts. If a gasoline with an RVP at or close to the upper limit is mixed (commingled) with a gasoline containing ethanol, the upper limit allowed for RVP could be exceeded.
The chemical compound in gasoline that contributes most to the RVP is butane. By decreasing or increasing the butane content in gasoline the RVP can be reduced or increased, respectively.
Very few data have been found on evaporative emissions from Brazil regarding vehicles running on neat ethanol or ethanol gasoline blends. However, since the lowest ethanol content of Brazilian fuel blends is 20%, the evaporative emissions from the vehicles are limited.
Page 87
11.2. Regulated Emissions
As the energy content (MJ/l) of ethanol-gasoline blends is lower than that of neat gasoline their use will probably cause fuel consumption to increase for the average driver.
The search for literature on the effects of ethanol blends on regulated emissions showed that very few data are available on emissions measured when using a blend of 10 % ethanol in gasoline. Since nearly all vehicles in Sweden are equipped with a three-way catalyst exhaust gas after-treatment system, data obtained in tests with such vehicles were of particular interest. The emission data found and discussed in this report are from investigations in Australia, Canada, England (UK), Sweden and the USA. One main drawback when collecting and studying data from different investigations is that the number of vehicles tested is often limited. The Orbital Engine Company has carried out a series of investigations on vehicles fuelled with ethanol blended gasoline initiated by Environment Australia. Most of these investigations have focused on a blend of 20 % ethanol in two or three grades of gasoline produced for the Australian market. However, the investigations carried out by Orbital have been of great value for this project since a broad spectrum of emission data are presented in the reports and they discuss many aspects such as fuels, vehicles, catalysts, vehicle performance and wear. Data on regulated, unregulated and evaporative emissions have been gathered and presented. There is only one main drawback with the data from the extensive tests involved; the fuel (gasoline) used for the tests with blended fuel and the neat gasoline had sulphur contents of up to 150 and 500 ppm, respectively, according to available information.
Investigations and evaluations conducted for the American Lung Association of Minnesota have shown that sulphur in the fuel has a considerable impact on both regulated and unregulated emissions.
A report from Environment Canada compares emission data from tests on ethanol blended gasoline and neat gasoline. The ethanol contents in the blended fuels were 10, 15 or 20 %. When comparing data from the different ethanol blends with data from tests on neat gasoline no dramatic differences were seen.
Beside the investigations carried out in Australia the emission tests carried out at Harwell, England, on five vehicles fuelled with a blend of 10 % ethanol in gasoline are of some interest, firstly because a 10 % ethanol in gasoline blend was used, and secondly because the vehicles used were models that are also used in Sweden. Generally the emission levels were low and no significant differences in NOx emissions were found. Emissions of CO and PM were significantly reduced when the use of blended was compared with neat gasoline.
Only limited data have been found concerning evaporative emissions. However, in some relevant investigations it has been noticed that emissions via permeation have increased when using ethanol blended gasoline. This has been especially significant in the USA after the strengthening of the evaporative emission regulations, since new measures had to be introduced to comply with the standards. One of these measures was to shift to the use of steel tanks for the fuel and another was to use new and more reliable tubes in the fuel lines.
In a paper from the Transportation Office of Energy Efficiency in Canada it is said that blending 10 % ethanol in gasoline (E10) will result in the energy content of the fuel being 3 % lower than the energy content of the base gasoline used for blending. Since this decrease in energy content will be partly compensated by “improved combustion efficiency” of the ethanol blended fuel the
Page 88
overall increase in fuel consumption when using E10 will be only 2 %. In comparison, increasing the speed of the vehicle from 100 km/h to 120 km/h increases fuel consumption by 20 %.
In the present report it has been emphasised that the method used for measuring hydrocarbons (HC) in the exhaust from motor vehicles using an alcohol blended fuel are not satisfactory from a legal perspective since the emissions of unburned alcohol are included in the readings of the instrument (FID). Therefore there is an urgent need to develop an analytical method that can determine HC emissions which are not affected by other “non HC” compounds present in the exhaust.
For regulated emissions the recommendation is that a broader more detailed study of the emissions, especially in low temperature conditions should be carried out, and tests including evaporative emissions at low temperatures. The resulting figures could probably be used to evaluate the environmental and health effects of using ethanol blends.
11.3. Unregulated Emissions
There is a need for updated emission factors of unregulated exhaust emissions. The components examined should include the chemical compounds and compound classes listed in the present report.
The emissions of aldehydes (especially acetaldehyde and, to a lesser degree, formaldehyde) and alcohols from vehicles running on alcohol/gasoline blends are expected to increase. There is no standard validated method for determining aldehyde and alcohol emissions from motor vehicles, so (an) appropriate method(s) must be developed (see also the conclusion and recommendation about HC emissions discussed above).
Due to the gasoline dilution effect of adding ethanol the emissions of benzene, toluene, ethyl benzene and xylene from blends are lower than those from neat gasoline, which is beneficial from environmental and health perspectives.
From the literature it is not clear whether there is risk that emissions of quinones from gasoline-fuelled vehicles will increase as the ethanol content increases in a gasoline/ethanol blend. Thus, it is recommended that a pilot investigation should be initiated to investigate if quinone emissions are related to the ethanol content of ethanol-gasoline blends.
There is clear, general interest from a health perspective in particle emissions from vehicles in the literature examined. It is recommended that particles emitted from vehicles fuelled with ethanol/gasoline blends should be thoroughly characterised chemically, and this characterisation should include measurements of their sizes and numbers.
11.4. Performance and Wear
During the study of the literature no evidence of serious engine wear and/or other material problems were found when a blend of 10 % ethanol in gasoline had been used. It has also been noted that this level of ethanol in gasoline has been used in the USA since the end of the 1970s. A blend of 10 % ethanol in gasoline has long been allowed in the USA by the car manufacturers without any serious restrictions on the warranties of their vehicles. Therefore, substantial experience of the use of ethanol blended gasoline has been collected over a long time. However, the limit for the ethanol content in gasoline has been set to 10 % under the warranty conditions.
Page 89
Extensive tests and studies carried out in Australia have found that using an ethanol-gasoline blend with 20 % ethanol increased the wear and other damage to the fuel system of the vehicles, especially at high accumulated mileages. It has not been possible to verify whether this is linked to the fact that the sulphur content of gasoline in Australia is relatively high, since this possibility was not considered in the reports from Australia. In Sweden the sulphur content in gasoline has been reduced to a maximum of 10 ppm. A high level of sulphur in the ethanol blended fuel may affect the engine fuel system since there is a small amount of acetic acid in neat ethanol (a maximum of 0.0025 % by weight, according to AMSE 1114).
In the light of the findings concerning the engine wear and other observed problems associated with the use of 20 % ethanol in gasoline the Australian government has decided to limit the amount of ethanol in gasoline to 10 %. Representatives of the oil industry and car owners also favoured the 10 % limit.
In contrast to the experiences in Australia, a study conducted in Minnesota (USA), in which two blends of ethanol in gasoline (one with 10 % and the other with 30 % ethanol) were examined, found that the ethanol caused no serious wear problems. The project included both laboratory tests and field trials. Unfortunately, however, no emission data are available from these tests.
In the 1970s and 1980s a quite extensive program was carried out in Sweden to study the effects of using alcohol blends in gasoline in motor vehicles. No such program has been established to collect experience and data regarding the use of ethanol blended gasoline since then. Therefore very few Swedish data are available.
11.5. Life Cycle Analysis
A number of LCAs have been carried out worldwide on the use of bio ethanol, but they are more or less based on country-specific framework conditions with respect to the production, distribution and use of alternative fuels. Furthermore, most of them focus solely on the emissions of greenhouse gases.
It can be concluded from the literature survey that LCA data with relevant framework conditions for the use of bio ethanol and bio ethanol mixed gasoline in a Swedish/European perspective are limited or lacking.
A new LCA based on Swedish framework conditions should focus on ethanol-gasoline blends with alcohol contents ranging from 5 to 20 %. Furthermore, as well as greenhouse gases (carbon dioxide, methane and nitrous oxide), regulated and other unregulated emissions should be included in it. The impact on the environment and health, of the production, distribution and use of the blends should be considered. Such an LCA could be structured in a similar way to the LCA published by Mata et al. (2003), but using specific Swedish framework conditions. Furthermore, both RVP-adjusted and non RVP-adjusted gasoline should be included.
Page 90
12. REFERENCES Aakko P. and Nylund N-O. Particle Emissions at Moderate and Cold Temperatures Using Different Fuels. SAE Technical Paper Series SAE 2003-01-3285, Special publication SP-1809, Warrendale US, (1977).
AAM/AIAM (1999)Automotive/Petroleum Industry Sulfur/Oxygen Test Program Test Program Elements. http://www.arb.ca.gov/fuels/gasoline/carfg3/Mtgs/4-27-99/testprog.doc Abel-Rahman A. and Osman M. Experimental Investigation on Varying the Compression Ratio of SI Engine Working under different Ethanol-Gasoline Fuel Blends. International Journal of Energy Research, Vol. 21, 31–40, (1997).
Acharya, G.K., Malhotra, N.R., Raje, N.R. and Bratnagar, A.K. Indian experiences with the use of Ethanol Gasoline and Ethanol Diesel Blends. ISAF XIV International Symposium on Aclcohol fuels: “The Rule of Alcohol Fuels in Meeting the Energy, Environmental and Economic Needs of the 21st Century”, (2002).
Alsberg T., Stenberg U., Westerholm R., Strandell M., Rannug U., Sundvall A., Romert L., Bernsson V., Petterson B., Toftgård R., Franzen B. Jansson M., Gustafsson J-Å. Egebäck K-E. and Tejle G. (1985) Chemical and biological characterization of organic material from gasoline exhaust particles. Environmental Science & Technology, Vol. 19, 43-50, (1985).
Almén J., Ludykar D. and Westerholm R. Unregulated Emission Factors for Light Duty Vehicles at Different Driving Patterns and Temperatures. AB Svensk Bilprovning, Motortestcenter, Rapport MTC, Haninge (1997).
American Lung Association of Minnesota. Twin Cities Gasoline Survey and Comparison – Summer 2003. American Lung Association of Minnesota B Clean Air Fuels Education Alliance EXECUTIVE SUMMARY (2003). http://www.cleanairchoice.org/outdoor/pdf/ExeSum_Summer 2003.pdf.
Andress, D. (2000). Air Quality and GHG Emissions Associated With Using Ethanol in Gasoline Blends. Prepared by: David Andress & Associates, Inc.Prepared for:Oak Ridge National Laboratory / UT-Battelle, Inc. and Office of Fuels Development Office of Transportation Technologies Energy Efficiency and Renewable Energy U.S. Department of Energy. Subcontract 11X-SY838, Under Contract DE-AC05-96OR22464. http://egov.oregon.gov/energy renew/Biomass/docs/FORUM/Andress2000.pdf
Apace Research Ltd. Intensive Field Trial of Ethanol/Petrol Blend in Vehicles, Volume 2, Appendices A-I Prepared by Apace Research Ltd, (1998).
Armstrong S. Ethanol. Brief Report on its Use in Gasoline. Cambridge Environmental Inc. 58 Charles St. Cambridge, MA 02141 US, (1999).
Augin, K. and Graham, L. The Evaluation of Ethanol – Gasoline Blends on Vehicle Exhaust and Evapoorative Emissions, Phase 1 Updated 10/25/02. ERMD Report # 00-64. Environmental Technology Centre, Emissions Research and Measurement Division, Environment Canada, (2004).
Page 91
Aulich T. and Allen L. Twin Cities Gasoline Survey and Comparison-Summer 2002. Final Report Prepared for: The Clean Air Fuels Education Alliance. Submitted to: Tim R. Gerlach , The American Lung Association of Minnesota. Energy & Environmental, Research Center, University of North Dakota, (2002).http://www.cleanairchoice.org/outdoor/pdf/gas%20survey-summer02.pdf
Australia Automobile Association, AAA, Response to the Environment Australia issues paper. Setting the Ethanol Limit in Gasoline, (2002). http://www.aaa.asn.au/submis/2002/Ethanol_March02.pdf
Australian Automobile Association Landmark, Determination on Ethanol in Gasoline, (2002a). http://www.aaa.asn.au/press/2002/22-08.htm
Australian Consumers Association. Ethanol in gasoline – should you care?, (2003).
Australian Government. Department of the Environment and Heritage. Setting the Ethanol Limit in Petrol, (2002). http://www.deh.gov.au/atmosphere/ethanol/publications/ethanollimit/background.html
Australian Government. A Literature Review Based Assessment on the Impacts of a 10% and 20% Ethanol Gasoline fuel Blend on Non-Automotive Engines, (2002).
Beer T., Grant T., Brown R., Edwards J., Nelson P., Watson H. and Williams D. Comparison of Transport fuels, Australian Greenhouse Office, The University of Melborne, (2002).
Beijing World Fuel Ethanol Congress, (2001). http://fuelethanolcongress.com/program/
Beijing Time China Pushes Use of Ethanol as Fuel, (2002). http://english.people.com.cn/200206/17/eng20020617_98009.shtml
Beijing Time. China Promotes Ethanol-Based Fuel in Five Cities: Zhengzhou, Luoyang and Nanyang in central China's Henan province, and Harbin and Zhaodong in Heilongjiang province, northeast China, (2002a). http://english.people.com.cn/200206/17/eng20020617_98009.shtml.
Bhanot, B., Chaudhari, M. Alternative Fuels: Driving India`s Future, (2003). http://www.araiindia.com/html/ContactUs.jsp or http://aic.mira.co.uk/ejournals/abnsample.pdf
Blinge M. Jämförande analys av producerade rapporter kring livscykelanalyser av drivmedel, Chalmers University of Technology, Rapport för Alternativbränsleutredningen, (1996).
Blinge M., Arnäs P-O., Bäckström S., Furnander Å.och Hovelius K. Livscykel Analys av Drivmedel. Chalmers University of Technology. Rapport för Alternativbränsleutredningen, (1997).
Bonnema G., Guse G., Senecal N., Gupta R., Jones B. and Ready K. Use of Mid-range Ethanol/Gasoline Blends in Unmodified Passenger Cars and Light Duty Trucks. MnCAR/MSU 106. Minnesota Center for Automotive Research, Minnesota State University, (2004).
Boswell R. The need for an ethanol industry in Australia, (2004).
Boström C-E., Gerde P., Hanberg A., Jernström B., Johansson C., Kyrklund T., Rannug A., Törnqvist M., Westerholm R. and Victorin K. (2001) Cancer risk assessment, indicators and
Page 92
guidelines for polycyclic aromatic hydrocarbons (PAH) in the ambient air. Environmental Health & Perspectives, Vol. 110, Supplement 3, pp 451 488, (2002).
BP. BP to commence ethanol sales in selected regional markets, (2003). http://www.indcor.com.au/Newspaper/031203%20BP%20Article.pdf
BP. Australia BP to dump ethanol blend, (2003a). http://www.dstc.edu.au/ListArchive/eclectika/archive/2003/02/msg00156.html
Camner P., Cothgreave I., Ewetz L., Gustavsson P., Hansson H.-C., Kyrklund T., Ljungquist S., Pershagen G., Victorin K. and Westerholm R. Particles in the ambient air as a risk factor for lung cancer. Swedish Environmental Protection Agency (SEPA) Report 4804, Stockholm, Sweden, (1997).
Canadian Renewable Fuel Association, (2004). [http://www.greenfuels.org/ethaterm.html].
CARB, California Air Resources Board, California Environmental Protection Agency, (1989).
CARB, California Air Resources Board, California Environmental Protection Agency, Cleaner burning gasoline: An assessment of its impact on ozone air quality in California, January, (1998).
Prakash C. Use of Higher than 10 volume percent Ethanol/Gasoline Blends in Gasoline Powered Vehicles. Prepared by: Motor Vehicle Emissions & Fuels Consultant forTransportation Systems Branch Air Pollution Prevention Directorate, Environment Canada, (1998).
Chevron. Motor Gasolines Technical Review, (2002-2005). http://www.chevron.com/prodserv/fuels/bulletin/motorgas/ Chevron. Motor Gasolines Technical Review, (2002-2005). 4 · Oxygenated Gasoline Methanol. (2002-2005a). http://www.chevron.com/prodserv/fuels/bulletin/motorgas/4_oxygenated-gasoline/pg2.asp.
Chevron. Gasoline and Driving Performance, (2002). http://www.chevron.com/prodserv/fuels/bulletin/motorgas/1%5Fdriving%2Dperformance/pg2.asp
Chevron. Chevron Gasoline Questions and Answers - Oxygenated Gasoline, (2004). http://www.chevron.com/prodserv/fuels/gas_qanda/oxygen.shtml China Daily. Liaoning vehicles to switch to ethanol gas in October, (2004).
Cheung, A., Flanders, K. and Walker, P. Ethanol-Blended Fuel policies: When will the cheap tricks end? (2003).
Colorado Department of Public Health and Environment. The Impact of a 10% Ethanol Blended Fuel on the Exhaust Emissions of Tier 0 and 1 Light Duty Gasoline Vehicles at 35°F, (1999).
Cho A., Di Stefano E., You Y., Rodriquez C., Schmitz D., Kumagai Y., Migel A., Eiguren-Fernandez A., Kobayashi T., Avol E. and Froines J. Determination of Four Quinones in Diesel Exhaust Particles, SRM 1649a, and Atmospheric PM2.5. Aerosol Science & Technology, Vol. 38, 68-81, (2004).
Page 93
Colón M., Pleil J., Hartlage T., Guardani M. and Martins M. Survey of volatile organic compounds associated with automotive emissions in the urban airshed of Sao Paulo, Brazil. Atmospheric Environment, Vol. 35, 4017-4031, (2001).
CONCAWE, EUCAR and the EU-Commissions/Joint Research Center, Well-to-Wheel Analysis of Future Automotive Fuels and Power Trains in the European Context, (2004).
CONSULADO GERAL DA ÍNDIA. PROÁLCOOL BRAZILIAN FUEL ETHANOL PROGRAM, (2005).
Deeb R., Sharp J., Stocking A., McDonalds S., West K., Laugier M., Alvarez J. Kavanaugh M. and Alvarez-Cohen L. Impact of Ethanol on Benzene Plume Lenghts: Microbial and Modeling Studies. Journal of Environmental Engineering, Vol 128, No. 9, 868- 875, (2002).
Department of Energy, Alternatives to Traditional Transportation Fuels, (1998). Department of Energy, DOE, Properties of Alcohol Transportation Fuels. Prepared by Meridian Corporation for US Department of Energy, 1991. http://www.hawaii.gov/dbedt/ert/afrw.html
Department of the Environment and Heritage. Fuel Quality Standards Act 2000. Clean Fuels Bulletin, Australian Government Department of the Environment and Heritage December (2003). http://www.deh.gov.au/atmosphere/cleaner-fuels/publications/pubs/december-2003.pdf
Department of the Environment and Heritage. Labelling Requirements from March 2004. Fuel Quality Standards Act 2000, (2004a). Department of the Environment and Heritage. http://www.deh.gov.au/atmosphere/ethanol/pubs/labelling.pdf.
Department of the Environment and Heritage. Fuel Quality Standards Act 2000, Clean Fuels Bulletin, Amendments to the Fuel Quality Standards Act 2000 Fuel Quality Standards. (2004) http://www.deh.gov.au/atmosphere/cleaner-fuels/publications/pubs/december-2004.pdf
Dietz W. Response Factors for Gas Chromatograpic Analysis. Journal of Gas Chromatograpy, Vol. 5, 68-71, (1967).
Egebäck, K.-E., Bertilsson B.-M. Chemical and Biological Characterizon of Exhaust Emissions from Vehicles Fueled with Gasoline, LPG and Diesel, SNV PM 1635, ISBN 91-7590-115-3, (1983).
Egebäck K.-E.,.Tejle, G. and Laveskog, A. Investigation of regulated and non gegulated emissions when using different fuel/engine combinations. (in Swedish: Undersökning av reglerade och icke reglerade föroreningar vid olika bränsle/motorkombinationer och olika temperaturer.). The Swedish Environmental Protection Board. (Naturvårdsverket) Report, SNV PM 1812, (1984).
EIA (2002) Potential Supply Impacts of Removal of 1-Pound RVP Waiver. US Energy Information Administration section. http://www.eia.doe.gov/oiaf/servicerpt/fuel/pdf/question7.pdf
Embassy of Brazil. The Brazilian National Programme of Fuel Alcohol (PROALCOOL), (2002). http://brazilembassyinindia.com/proalcool.htm.
Page 94
Environment Australia. Setting the Ethanol Limit in Petrol. An Issues Paper, (2002). http://www.deh.gov.au/atmosphere/ethanol/publications/ethanol-limit/pubs/ethanoljan02.pdf.
Environment Australia. A Literature Review Based Assessment on the Impacts of a 20% Ethanol Gasoline Fuel Blend on the Australian Vehicle Fleet, (2002a).
Environment Canada. Effect of Ethanol on Fuel Properties, (2005). http://www.ec.gc.ca/transport/publications/ethgas/ethgas4.htm Ethanol Curriculum Online TEFL Module 5 (2005). Module 5, Ethanol: The Fuel. http://www.nwicc.com/pages/continuing/business/ethanol/Module5.htm Ethanol Industry in Thailand. Outlook of Raw Materials for Ethanol Industry in Thailand, (2004).
Federal Government. Federal government Set 10 Per Cent Ethanol Limit, (2003). http://www.deh.gov.au/minister/env/2003/mr11apr03.html.
Federal Government. Fuel Quality Standards Amendment Bill 2003. Bills Digest No. 30 2003–04, (2003a). http://www.aph.gov.au/library/pubs/bd/2003-04/04bd030.pdf. [04bd030]
The French Authority for Environment and Energy, ADEME, Ecobilan, Pricewaterhouse Coopers and DIREM, Energy and greenhouse gas balances of bio fuels production chains in France, (2002).
Furey, R. and King J. Evaporative and Exhaust Emissions from Cars Fueled with Gasoline Containing Ethanol or Methyl tert-Bytyl Ether. General Motors Research Laboratories. SAE paper 800261, February, (1980).
Furey R. Volatility Characteristics of Gasoline-Alcohol and Gasoline-Fuel Blends. General Motors Research Laboratories. SAE paper 852116, (1985).
Furey R. and Perry K. Vapour Pressures of Mixtures of Gasolines and Gasoline-Alcohol Blends. General Motors Research Laboratories. SAE paper 861557, (1986).
Furey R. and Perry K. Volatility Characteristics of Blends of Gasoline with Ethyl Tertiary-Bytyl
Ether (ETBE). General Motors Research Laboratories. SAE paper 901114, (1990).
Ford Motor Company (2003). 2003 Taurus Flexible Fuel Vehicle
Furey R. and Jackson M. Exhaust and Evaporative Emissions from a Brazilian Chevrolet fuelled with Etanol-Gasoline Blends. SAE Technical Paper Series SAE 779008, Warrendale US, (1977).
Gaffney, Jeffrey S.; Marley, Nancy A.; Martin, Randal S.; Dixon, Roy W.; Reyes, Luis G.; Popp, Carl J. Potential Air Quality Effects of Using Ethanol-Gasoline Fuel Blends: A Field Study in Albuquerque, New Mexico. Environmental Science and Technology, Vol. 31, 3053-3061, (1997).
General Motors, Argone National Laboratory, BP, ExxonMobil, Shell and TotalFinal Elf. Well to Wheel Energy use and Greenhouse Gas Emissions of Advanced Fuel/vehicle systems, (2002).
Page 95
Grosjean D., Grosjean E. and Moreira L. Speciated Ambient Carbonyls in Rio de Janeiro, Brazil, Environmental Science and Technology, Vol. 36, 1389-1395, (2002).
Hamilton B. Gasoline FAQ - Part 2 of 4, (2004). http://www.faqs.org/faqs/autos/gasoline-faq/part2/
Hammel-Smith C., Fang J, Powders M. and Aabakken J. Issues Associated with the Use of Higher Ethanol Blends (E17-E24). National Renewable Energy, (2002). http://www.nrel.gov/docs/fy03osti/32206.pdf.
Harly R. and Coulter-Burke S. Relating Liquid Fuel and Headspace Vapour Composition for California Reformulated Gasoline Samples Containing Ethanol. Environmental Science and Technology, Vol. 34, 4088-4094, (2000).
Hart Downstream Energy Services. Setting a Quality Standard for Fuel Ethanol. Report Presented to: Department of the Environment and Heritage Submitted by:International Fuel Quality Center, Hart Downstream Energy Services, (2004). http://www.deh.gov.au/atmosphere/ethanol/publications/pubs/ifqc-report.pdf.
Hellens, J. Fuel Regulations in Australia. BP Australia, (2002). http://www.aip.com.au/pdf/fuel_%20regs.pdf
He B., Wang J., Hao J., Yan X. and Xiao J. A Study on Emissions Characteristics of an EFI Engine with Ethanol Blended Gasoline Fuels. Atmospheric Environment, Vol. 37, 949-957, (2003).
Heinrich U., Fuhst R., Dasenbrock C., Muhle H., Koch W. and Mohr U. Long term inhalation exposure of rats and mice to diesel exhaust, carbon black and titanium dioxide. In Proceedings of the 5th International Inhalation Symposium on Toxic and Carcinogenic Effects of Solid Particles in the Respiratory Tract, March 1993, Hannover, Germany, (1993).
Heinrich U., Fahst R., Rittinghausen S., Creutzenberg O., Bellmann B., Koch W. and Leven K. Chronic Inhalation Exposure of Wistar Rats and two Different Strains of Mice to Diesel Engine Exhaust, Carbon Black and Titanium dioxide. Inhalation Toxicology 7, 533-556, (1995).
Hsieh W., Chen R., Wu T. and Lin T. Engine Performance and Pollutant Emission of a SI Engine using Ethanol Gasoline Blended Fuels. Atmospheric Environment, Vol. 36, 403-410, (2002).
IARC. International Agency for Research on Cancer. Monographs on the evaluation of carcinogenic risks of chemicals to humans: Polynuclear Aromatic Compounds, part 1, Chemical, environmental and experimental data, Volume 32, Lyon, France, (1983).
IARC. International Agency for Research on Cancer. Monographs on the evaluation of carcinogenic risks of chemicals to humans: Diesel and gasoline engine exhausts and some Nitro-PAH, Volume 46, Lyon, France, (1989).
Industridepartementet (1986). Alcohols as Motorfuels (in Swedish). SOU 1986:51, (1986).
Isaias de Carvalho M., Leal M. and da Silva J. Assessment of greenhouse gas emissions in the production and use of ethanol in Brazil, Government of the state of Sao Paulo, (2004).
Page 96
Johnsson A. and Bertilsson B-M. Formation of Methyl Nitrite in Engines Fueled with Gasoline/Methanol and Methanol/Diesel. Environmental Science & Technology, Vol. 16, 106-110, (1982).
Joseph, H. Junior “Vehicular Ethanol Fuel”. Technical & Exhaust Emission Experience in Brazil. Brazilian Automobile Manufacturers Association, (1998).
Koroteny D. A Comparison Between Refulmulated Gasoline and low RVP Gasoline as Alternative Strategies for Meeting NAAQ Standards for Troposperic Ozone. Memorandum: March 22 1996, US Environmental Protection Agency , Air and Radiation Office of Transportation and Air Quality, Fuels Studies and Standards Group, (1996).
Kyrklund T. Swedish Environmental Protection Agency. Personal communication, (2004).
Kemp I. Fuel Quality Information Standard (Ethanol) Determination 2003. 2003122302, (2003). http://scaleplus.law.gov.au/html/instruments/0/33/pdf/2003122302.pdf
KFB. Low Contents of Alcohols in Gasoline. (In Swedish: Inblandning av låga halter av alcoholer i bensin). Report for The Swedish Transport and Communications Research Board (KFB). Swedish version KFB-Meddelande 1999:4, (1999).
Krause K and Korotney D. Water Phase Separation in Oxygenated Gasoline. Corrected version of Kevin Krause memo. (1995). http://www.epa.gov/otaq/regs/fuels/rfg/waterphs.pdf
Lagen om motorfordons avgasrening och motorbränslen, 2001:1080, (2001).
Launder K. From Promise to Purpose: Opportunities and Constraints for Ethanol Based Transportation Fuels- A Plan B Research Report, Submitted to Michigan State University In partial fulfilment of the requirements for the degree of Masters of Science, Department of Resource Development, (2001).
Laveskog, A. and Egebäck, K.-E. Addition of Small Amounts of Alcohol to Gasoline, Report in English prepared for MTC (Motortestcenter, Sweden, (1999).
Lonneman W. Comparison of hydrocarbon composition in Los Angeles for the year 1968 and 1997. Preceedings of the EPA/AWMA Symposium on Measurement of Toxic and Related Air Pollutants, Carry, NC Air & Waste Management Association, Sewickley, PA, 356-365, (1998).
Lovanh N., Hunt C. Alvarez P. Effect of ethanol on BTEX biodegradation kinetics: aerobic continuous culture experiments. Water Research 36(15), 3739-3746, (2002).
Lu-Karlsson H. Characterisation of the Evaporative Emissions from E85, E10, Gaoline and Reference Gasoline Fuels, MTC report, (1999).
Malhotra, R. Development of Alternative Fuels in India. Presentation at a Regional Workshop on Fuel Quality and Alternate Fuels 2-4 May 2001, New Delhi, India. Organised by Asian Development Bank, (2002). http://www.adb.org/Documents/Events/2001/RETA5937/New_Delhi/documents/nd_23_malhotra.pdf
McLeana H. and Laveb L. Evaluating Automobile fuel/Propulsion System Technologies. aDepartment of Civil Engineering, University of Toronto, bGraduate School of Industrial
Page 97
Administration, Carnegie Mellon University, (2002). http://engineering.dartmouth.edu/~cushman/courses/engs171/EvalAutoFuel.pdf
McArragher J. Minimum RVP Limits in CEN Gasoline Specification. Shell International, UK, 20/6, (1996).
Market Barriers (2004). Testing Gasoline Containing 20% Ethanol (E20) - Phase 2B Final Report: Market Barriers to the Uptake of Bio fuels Study. Department of the Environment and Heritage
Mata T., Smith R., Young D. and Costa C. Life Cycle Assessment of Gasoline Blending Options, University of Porto, Portugal, (2003).
Ministery for the Environment and Heritage. Federal Government to Set 10 Per Cent Ethanol Limit. (2003;2004). http://www.deh.gov.au/minister/env/2003/mr11apr03.html.
Minister for the Environment and Heritage. Fuel Quality Standards Act 2000 labelling requirements from 1 March 2004, (2004) http://www.deh.gov.au/atmosphere/ethanol/publications/labelling.html
Mishra S. India Ethanol Coalition Joining hands for the future fuel, (2002). http://www.cleantechindia.com/eicnew/India.htm
Nan L., Best G., Coelho de Carvalho Neto C..Integrated energy systems in China - The cold Northeastern region experience. Food and Agriculture Organization of the United Nations, Rome, (1994). http://www.fao.org/docrep/T4470E/T4470E00.htm.
National Research Council. Diesel Cars Benefits, Risk and Public Policy. National Academy Press: Washington DC, (1982).
Natural Heritage Trust. Setting National Fuel Quality Standards, Proposed Standards for Fuel Parameters (Gasoline and Diesel) Revised Commonwealth Position, (2000). http://www.deh.gov.au/atmosphere/cleaner-fuels/publications/pubs/fuel0900.pdf
National Ethanol Vehicle Coalition. Why do ethanol vehicles require a certain type of motor oil? Does this refer to dedicated ethanol vehicles only? (2004). http://www.e85fuel.com/faqs/motoroil.htm
NISSAN. Nissan and Gasohol (E10), (2004). http://www.nissan-th.com/www_eng/news1.asp
Nitsche M. Respiratory Health Effects of nitrogen dioxide Exposure and Current Guidelines. International Journal of Environmental Health Research, Vol. 9, 39 – 53, (1999).
NREL. Keeping the Heat on Cold-Start Emissions NREL's Insulated Catalytic Converter Slashes Automotive Air Pollution. Technology Brief, (1996). http://www.nrel.gov/vehiclesandfuels/energystorage/pdfs/techbr.pdf
NREL. Issues Associated with the Use of Higher Ethanol Blends (E17-E24), (2002).
NREL/TP-510-32206. Contract No. DE-AC36-99-GO10337. http://www.nrel.gov/docs/fy03osti/32206.pdf.
Page 98
NREL. Do You Own a Flexible-Fuel Vehicle? NREL/FS-540-33058, (2003). http://www.nrel.gov/docs/fy03osti/33058.pdf
NRMA. Keep Strict Limit on Ethanol: Ethanol levels in gasoline must not exceed 10 per cent until research proves there is no negative effect on engines or driving quality, the National Roads and Motorists' Association Limited said today, (2002). http://www.mynrma.com.au/releases2002_021011_1.asp
NRMA. NRMA to Federal Government: Act Now on Ethanol. The Chief Executive of NRMA Motoring & Services, Mr Rob Carter, said he was angered tonight by Federal Cabinet's refusal to control ethanol levels in petrol, the central issue threatening cars belonging to NRMA's two million members in NSW, (2002a). http://www.mynrma.com.au/releases2002_021218_1.asp
NRMA. Understanding Ethanol, (2003). http://www.mynrma.com.au/files/1/ethanol.pdf
Nynäs, OK and SDAB. Distribution of Blend Fuels. Final report on trials with distribution and storage of methanol-blended leadfree gasoline, (1983)
Oak Ridge National Laboratory. Fuel Specifications and Fuel Properties issues and Their Potental Impact on the Use of Ethanol as a Transportation Fuel. Phase III Project Deliverable Report Ethanol Project, (2002). http://biodiesel.pl/uploads/media/FUEL SPECIFICATIONS AND FUEL PROPERTY ISSUES AND THEIR POTENTIAL IMPACT ON THE USE OF ETHANOL AS A TRANSPORTATION FUEL.pdf
Office of Legislative Drafting. Attorney-General’s Department Fuel Quality Standards Act 2000 Act No. 153 of 2000 as amended. This compilation was prepared taking into account amendments up to Act No. 42 of 2004, (2004). http://scaleplus.law.gov.au/html/pasteact/3/3418/pdf/FuelQualityStand2000.pdf
Office of Oil and Gas of the Energy Information (2002). Supply Impacts of an MTBE Ban http://www.eia.doe.gov/oiaf/servicerpt/fuel/pdf/question1.pdf
Orbital Engine Company. A Literature Review Based Assessment on the Impacts of a 20% Ethanol Gasoline Fuel Blend on the Australian Vehicle Fleet. Report to Environment Australia, November, (2002).
Orbital Engine Company. Market Barriers to the Uptake of Bio fuels Study. A Testing Based Assessment to Determine Impacts of a 20% Ethanol Gasoline Fuel Blend on the Australian Passenger Vehicle Fleet Report to Environment Australia March 2003, (2003). http://www.deh.gov.au/atmosphere/ethanol/publications/2000hours-vehicle-fleet/pubs/2000-hours-vehicles.pdf.
Orbital Engine Company. Market Barriers to the Uptake of Bio fuels Study Testing Gasoline Containing 20% Ethanol (E20). Phase 2B Final Report to the Department of the Environment and Heritage, (2004). http://www.deh.gov.au/atmosphere/ethanol/publications/biofuels-2004/pubs/phase2b-final-report.pdf
Patyk A. and Reinhardt G. Life Cycle Analysis of Bio Fuels for Transportation Used in Fuel Cells and Conventional Technologies under European Condition, Institute für Energie und Umwelts Forschung, Heidelberg, Germany, (2002).
Page 99
People's Daily. Online Liaoning adopts ethanol gasoline, (2004). http://english.people.com.cn/200411/02/eng20041102_162456.html.
Pott F. Dieselmotorabgas - Tierexperimentelle Ergebnisse zur Risikoabschätzung. Ver. Dtsch. Ing. Ber. No. 888: 211-224, (1991).
Pott, F. and Heinrich, U. Relative Significance of Different Hydrocarbons for the Carcinogenic Potency of Emissions from Various Incomplete Combustion Processes. IARC Sci. Publ. 104: 288-297, Lyon, France, (1990).
Powers S., Alvarez P. and Rice D. Increased Use of Ethanol in Gasoline and Potential Ground Water Impacts. Chapter 1, UCRL-AR-145380, (2001).
Prakash, C (1998) Use of Higher than 10 volume percent Ethanol/Gasoline Blends In Gasoline Powered Vehicles, Motor Vehicle Emissions & Fuels Consultant, prepared for Transportation Systems Branch Air Pollution Prevention Directorate Environment Canada.
Reading A., Norris, J., Feest A. and Payne E. Ethanol Emissions Testing, E&E/DDSE/02/021 Issue 3, AEAT Unclassified, (2002). http://www.dft.gov.uk/stellent/groups/dft_roads/documents/page/dft_roads_032580.pdf
Renewable Fuels Association. Thailand Endorses Ethanol to Reduce Oil Use, Help Farmers, (2001). http://www.ethanolrfa.org/ereports/er112001.html
Renewable Fuels Association. Fuel Ethanol Industry Guidelines Specifications, and Procedures. RFA Publication # 960501 Revised May 2002, (2002). http://www.pei.org/FRD/rfa_pub.pdf
Rodhe H., Department of Meteorology, Stockholm University, Sweden, personal communication, (2005).
Schifter I., Vera M., Diaz L., Guzman E., Ramos F. and Lopez-Salinas E. Environmental Implications on the Oxygenation of Gasoline with Ethanol in the Metropolitan Area of Mexico City. Environmental Science & Technology, Vol. 35, 1893-1901, (2001).
Schuetzle D., Lee F. and Prater T. The Identification of Polynuclear Aromatic Hydrocarbon (PAH) Derivatives in Mutagenic Fractions of Diesel Particulate Extracts. International Journal of Environmental Analytical Chemistry, Vol 9, 93-144, (1981).
Schuetzle D., Siegl W., Jensen T., Dearth M., Kaiser E., Gorse R., Kreucher W. and Kulik E. The relationship between Gasoline Composition and Vehicle Hydrocarbon Emissions. A Review of Current Studies and Future Research Needs. Environmental Health & Perspectives, Vol. 102, 3-12, (1994).
Science Fair Projects Encyclopedia. Alcohol fuel, (2004). http://www.all-science-fair-projects.com/science_fair_projects_encyclopedia/Alcohol_fuel
SDAB (1983). Effects of Gasoline, M15, Methanol and Ethanol on Plants, Soil and Aquatic Organisms (in Swedish). Swedish Motor Fuel Technology Co for the National Swedis Board for Energy Source Development. Sekab (2004). http://www.sekab.se/word/Etanol99.pdf
Shell Australia. Downstream Petroleum, (2003). http://www.aip.com.au/pdf/Downstream_Petroleum_2003_Report.pdf.
Page 100
Siwarasak P. and Wirivutthikorn, W. Experimental Research of Ethanol Fermentation from Rice Straws and Bagasse. ISAF XIV International Symposium on Aclcohol fuels: “The Rule of Alcohol Fuels in Meeting the Energy, Environmental and Economic Needs of the 21st Century”, (2002).
Sjödin Å., Westerholm R., Almén J. and De Serves C. Emissions of regulated and non-regulated compounds from high- and low-emitting gasoline light-duty vehicles. Transport and Air Pollution, 9:th Symposium Avignon, ISBN 2-85782-533-1.Vol 1. pp 135-142, (2000).
SOU, Provmetoder och emissioner vid användning av alternativa motorbränslen. Alternativbränsleutredningen SOU 1996:184 (1997).SNV 1635. Chemical and Biological Characterization of Exhaust Emissions from Vehicles Fueled with Gasoline, Alcohol, LPG and Diesel. National Swedish Environment Protection Board. Report SNV 1635. (1983).
STU. Alcohols and alcohol blends as motor fuels. Vol. II A och Vol.II B, ”State-of-the-Art” report. Chapters 1-7 och Chapters 8-14, Prepared by The Swedish Motor Fuel Technology Co. (SDAB), Information 640-1986. (1986).
STU (1987). Project M100 – A Test With Methanol-Fuelled Vehicles in Sweden. Prepared by SDAB. STU information no. 640-1987.
The Swedish National Energy Administration. Motor Alcohols in Sweden (in Swedish). Statens Energiverk 1986:7, (1986).
Swedish Rescue Servises Agency (SRSA) Persson Å. Räddningsverket, Regelverk för E85, e-mail to Mattebo R. SEKAB 17/12, (2004).
Szwarc A. A Use of Bio-Alcohol in Brazil. Presentation at “In-Session Workshop on Mitigation SBSTA 21 / COP 10 December 9, 2004 Buenos Aires”. Szwarc is a consultant at Ministry of Science and Technology of Brazil, (2004).
TEFL Online, Modul 5 Ethanol, The Fuel, (2005). http://www.nwicc.com/pages/continuing/business/ethanol/Module5.htm
Thanonkeo, P., Laopaiboon, L. and Laopaiboon, P. Renewable Alternativefron Sweet Sorghum. ISAF XIV International Symposium on Aclcohol fuels: “The Rule of Alcohol Fuels in Meeting the Energy, Environmental and Economic Needs of the 21st Century, (2002)
The Gazette of India (2002). Ministry of Petroleum and Natural Gas Resolution New Delhi, 3RD September, 2002 No. P-45018/28/2000-C, (2002). http://www.ethanolindia.net/ethanol_govt.html
Toptech. Application: Ethanol Blending with Multi Load, (2004). http://www.toptech.com/brochures/DOC-MKT-ETH0001_EthanolBlending_REV2.pdf
Transport Office of Energy Efficiency in Canada, (2004). Safety and performance Canada: http://oee.nrcan.gc.ca/transportation/fuels/ethanol/safety.cfm?attr=8
Törnqvist M., Rannug U., Jonsson A. and Ehrenberg L. Mutagenicity of methyl nitrite in Salmonella typhimurium. Mutation Research. Vol. 117, 47-, (1983).
Page 101
Törnqvist M. Kautiainen A., Gatz R. and Ehrenberg L. Haemoglobin adducts in animals exposed to gasoline and diesel exhaust. 1. Alkenes. Journal of Applied Toxicology. Vol. 8, 159-170, (1988).
Törnqvist M., Segerbäck D. and Ehrenberg L. The ”rad-equivalence approach” for assessment and evaluation of cancer risks, exemplified by studies of ethylene oxide and ethane. In: Human carcinogen exposure, biomonitoring and risk assessment. Edited by: R. Garner, P. Farmer, G. Steele and A.Wright. Oxford IRL Press. 141-155, (1991).
Törnqvist M. and Ehrenberg L. On Cancer Risk Estimation of Urban Air. Environmental Health & Perspectives. Vol. 102, 173-182, (1994).
Uppal, J. (2002). Indian Ethanol Program – The Road Ahead! Seminar on Opportunities & Prospects for Use of Ethanol, India-Brazil Partnership. Winrock International India. http://www.ficci.com/ficci/media-room/speeches-presentations/2002/aug/aug14-ethanol-jai.htm
US Commercial Service. The Significance of Developing Ethanol Gasoline and the Pilot Use of Ethanol Gasoline. American Embassy, Beijing Vol. 2 No. 137, (2003). http://www.buyusa.gov/china/en/ccb030703.html
US Department of Energy. Properties of Alcohol Transportation Fuels. Alcohol Fuels Reference Work No. 1. Prepared for: Bio fuels Systems Division, Office of Alternative Fuels, U.S. Department of Energy Prepared by: Fuels and Transportation Division, Meridian Corporation, 4300 11W Street ~.Alexandria, Virginia 22302, July 1991, (1991). http://www.hawaii.gov/dbedt/ert/afrw/afrw-01.pdf
US Department of Energy. Guidebook for Handling, Storing, & Dispensing Fuel Ethanol, (2002). http://www.agriculture.state.ia.us/pdfs/ethguide.pdf.
US EPA. Cancer Risk from Outdoor Air Toxics. Vol., Washington DC, (1990).US EPA. Clean Fuels: An Overview, EPA 400-F-92-008 US Environment Protection Agency, Office of Mobile Sources, (1992). http://www.epa.gov/otaq/consumer/06-clean.pdf
US EPA. Final Regulatory Impact Analysis for Reformulated Gasoline. EPA420-R-93-017, (1993). http://www.epa.gov/otaq/regs/fuels/rfg/420r93017.pdf US EPA (1996). Agency Correspondence Regarding RFG and Low RVP Gasoline http://www.epa.gov/otaq/regs/fuels/rfg/api-let.pdf
US EPA (1999). Control of Air Pollution from New Motor Vehicles: Proposed Tier 2 Motor Vehicle Emissions. Standards and Gasoline Sulfur Control Requirements. http://www.epa.gov/otaq/regs/ld-hwy/tier-2/nprm/t2phila2.pdf
US Senate. A bill to amend the Clean Air Act to address problems concerning methyl tertiary butyl ether, and for other purposes. Bill Summary & Status for the 107th Congress, (2001). http://thomas.loc.gov/cgi-bin/bdquery/z?d107:SN00950:@@@D&summ2=0&
Utah Petroleum Association (2004)- Gasoline – Is It All the Same?
Wang M., Saricks C. and Santini D. Effects of Fuel Ethanol Use on Fuel-Cycle Energy and Greenhouse Gas Emissions, Argonne National Laboratory, US, (1999).
Page 102
Wild D., King M., Gocke E. and Eckhardt K. Study of Artificial Flavoring Substances for Mutagenicity in the Salmonella/microsome, Basc and micronucleus tests. Food and Chemical Toxicology 21(6), 707-719, (1983).
Virginia Department of Environmental Quality (2005). Control Strategy Briefing Fredriksburg Air Quality Committee. http://www.deq.virginia.gov/air/documents/planning/10
World Association of Beet and Cane Growers (2001). THAILAND APPROVES PLAN TO REDUCE TAX ON ETHANOL. http://www.ifap.org/wabcg/faxsheet0101.html.
WORLD-WIDE FUEL CHARTER. December 2002, (2002). http://www.oica.net/htdocs/fuel%20quality/WWFC_Dec2002_Brochure.pdf
WORLD-WIDE FUEL DECEMBER 2002: Response to Comments on WORLD-WIDE FUEL CHARTER. December (2002). http://www.autoalliance.org/archives/wwfcadden.pdf
Subject: Gasoline FAQ - Part 1 of 4. (2002). http://www.cs.uu.nl/wais/html/na-dir/autos/gasoline-faq/part1.html. and Gasoline FAQ. http://www.repairfaq.org/filipg/AUTO/F_Gasoline3.html
WWFC, World Wide Fuel Charter. June 2002, European Automobile Manufacturers Assocoation (ACEA), Alliance of Automobile Manufacturers, Engine Manufacturers Association (EMA) and Japan Automobile Manufacturers Association (JAMA), (2002).
Xia T., Korge P., Weiss J., Li N., Venkatesen M. and Sioutas C. Quinones and Aromatic Chemical Compounds in Particulate Matter Induce Mitochondrial Dysfunction: Implications for Ultrafine Particle Toxicity. Environmental Health Perspectives, Vol. 112, No. 14, 1347-1358, (2004).
Young M., Saricks C. and Wu M. Fuel-Cycle Fossil Energy Use and Greenhouse Gas Emissions of Fuel Ethanol Produced from US Midwest Corm, Argonne National Laboratory, US (1997).
Page 103
13. ABBREVIATIONS API
B(a)P
American Petroleum Institute
benzo(a)pyrene
BRON
BTEX
Blending Research Octane Number
benzene toluene, ethyl benzene, xylene
CARB California Air Resource Board
CH3CH2-OH Ethanol
CO Carbon monoxide
CONCAWE The Oil Companies´ European Association for Environment, Health and Safety in Refining and Distribution
DME
DOE
Dimethyl ether
Department of Energy
EIA US Energy Information Administration
EFI Electronic Fuel Injection
Eth Ethanol
EU European Union
EUCAR European Council for Automotive Research and Development
Evap Evaporative
E85 15% conventional gasoline and 85% ethanol
FBP Final Boiling Point
FFVs Flexible Fuelled Vehicle
FID Flame Ionization Detector
Gas Gasoline
Gasohol A gasoline extender made from a mixture of gasoline (90%) and ethanol (10%; often obtained by fermenting agricultural crops or crop wastes) or gasoline (97%) and methanol, (3%)
GM General Motors
GWP Global Warming Potential
HC Hydrocarbons
IBP Initial Boiling Point
IEA The International Energy Agency
Page 104
IEA
JRC
International Symposium on Alcohol Fuels
EU Joint Research Centre
KPa Kilo Pascal
LPG
MTBE
Natural gas and Motorgas/Petroleum gas
Methyl Teriary Buthyl Ether
MON Motor Octane Number
NDIR Nondispersive Infrared
NMOG Non Methane Organic Gases
NOx Nitrogen oxides
PAC Polycyclic Aromatic Compounds
PAH Polycyclic Aromatic Hydrocarbons
PAN Peroxy acetyl nitrate
PULP Perth unleaded petrol
Psi
RFA
Pounds per square inch
Renewable Fuels Association
RFG Reformulated Gasoline
RON Research Octane Number
RVP Reid Vapour Pressure
RCGWE Relative Contribution to the Global Warming Effect.
SEKAB
SPI
STAB
STU
SHED
Svensk Etanolkemi AB
Swedish Petroleum Institute
Swedish Motor Fuel Technology Co.
Swedish National Board for Technical Development
Evaporative Test Chamber (Sealed Housing for Evaporative Determination)
THC Total Hydrocarbons
TWC Three Way Catalyst
ULP
US EPA
Unleaded petrol
US Environmental Protection Agency
VOC Volatile organic compounds
Vol %
VTT
Volume percent
Technical Research Centre of Finland
Page 105
14. APPENDIX 1
14.1. Emission tests in Canada
The following five tables, A1 to A5, list emission data generated during the tests carried out in Canada and presented in section 7.2 of the main part of the report. As can be seen there is a considerable variation in emission levels from vehicle to vehicle. It is particularly noteworthy that the Grand Am and Silverado show higher levels of emissions than the other vehicles
Table A1. Emissions of CO when using neat gasoline and three different blends of ethanol. Vehicle ⇒ Grand
Am Honda Insight Silverado Echo Civic
US FTP cycle CO g/km CO g/km CO g/km CO g/km CO g/km 0 % Ethanol 0.920 0.205 0.963 0.280 0.305 10 % Ethanol 0.808 0.218 0.740 0.261 0.273 15 % Ethanol 0.709 0.186 0.938 0.224 0.205 20 % Ethanol 0.777 0.143 0.740 0.242 0.155 Table A2. Emissions of HC when using neat gasoline and three different blends of ethanol. Vehicle ⇒ Grand
Am Honda Insight Silverado Echo Civic
US FTP cycle HC g/km HC g/km HC g/km HC g/km HC g/km 0 % Ethanol 0.056 0.027 0.075 0.050 0.025 10 % Ethanol 0.068 0.027 0.068 0.050 0.021 15 % Ethanol 0.056 0.024 0.087 0.049 0.017 20 % Ethanol 0.060 0.024 0.068 0.051 0.021 Table A3. Emissions of NOx when using neat gasoline and three different blends of ethanol. Vehicle ⇒ Grand
Am Honda Insight Silverado Echo Civic
US FTP cycle NOx g/km NOx g/km NOx g/km NOx g/km NOx g/km 0 % Ethanol 0.118 0.026 0.068 0.087 0.030 10 % Ethanol 0.131 0.033 0.081 0.087 0.032 15 % Ethanol 0.124 0.049 0.068 0.068 0.039 20 % Ethanol 0.124 0.068 0.081 0.068 0.033 Table A4. Emissions of CO2 when using neat gasoline and three different blends of ethanol. Vehicle ⇒ Grand
Am Honda Insight Silverado Echo Civic
US FTP cycle CO2 g/km CO2 g/km CO2 g/km CO2 g/km CO2 g/km 0 % Ethanol 249.2 101.9 303.9 161.6 179.6 10 % Ethanol 244.3 105.0 305.8 162.8 176.5 15 % Ethanol 247.4 103.2 307.0 162.8 176.5 20 % Ethanol 248.6 100.1 307.0 161.0 175.3
Page 106
Table A5. Fuel consumption when using neat gasoline and three different blends of ethanol. Vehicle ⇒ Grand
Am Honda Insight Silverado Echo Civic
US FTP cycle FC l/10 km
FC l/10 km
FC l/10 km
FC l/10 km
FC l/10 km
0 % Ethanol 1.063 0.435 1.293 0.701 0.764 10 % Ethanol 1.077 0.463 1.346 0.720 0.783 15 % Ethanol 1.102 0.464 1.352 0.731 0.790 20 % Ethanol 1.144 0.460 1.410 0.739 0.803
14.2. Emission tests in UK
The following four tables, A6 to A9, list emission data generated during the tests carried out in England and presented in section 7.3 of the main part of the report.
In Tables A6, A7 and A8 the emission data and fuel consumption of interest are presented; the measurements of regulated emissions and fuel consumption in Table A6, and those of unregulated emissions in Tables A7 and A8. As can be seen there is considerable variation in emission levels from vehicle to vehicle. It can also be seen that some vehicles show an increase in emissions when ethanol blended fuel is used, while others show a decrease.
Table A6. Summary of regulated emissions for all tested vehicles Vehicle 1 Toyota (Yaris) running on base gasoline fuel. Drive cycle CO2 CO THC NOX PM Fuel
cons. g/km g/km g/km g/km g/km g/km
Cold ECE 165.9 1.904 0.307 0.150 0.0059 53.55 Cold EUDC
110. 7 0.512 0.018 0.027 0.0058 35.16
Vehicle 1 Toyota (Yaris) running on E10 fuel Drive cycle CO2 CO THC NOX PM Fuel
cons. g/km g/km g/km g/km g/km g/km Cold ECE 162.6 2.787 0.323 0.108 0.0018 55.04 Cold EUDC
109.5 0.047 0.016 0.035 0.0011 36.04
Vehicle 6 Toyota (Yaris) (repeated) running on base gasoline fuel. Drive cycle CO2 CO THC NOX PM Fuel
cons. g/km g/km g/km g/km g/km g/km
Cold ECE 161.5 1.328 0.402 0.207 0.0083 51.99 Cold EUDC
107. 1 0.465 0.038 0.024 0.0049 34.03
Page 107
Vehicle 1 Toyota (Yaris) (repeated) running on E10 fuel. Drive cycle CO2 CO THC NOX PM Fuel
cons. g/km g/km g/km g/km g/km g/km
Cold ECE 156.1 1.577 0.296 0.132 0.0084 52.26 Cold EUDC
106.1 0.425 0.019 0.029 0.0034 35.00
Vehicle 2 Vauxhall (Omega) running on base gasoline fuel. Drive cycle CO2 CO THC NOX PM Fuel
cons. g/km g/km g/km g/km g/km g/km Cold ECE 386.7 1.159 0.551 0.243 0.0058 123.04 Cold EUDC
211.7 0.225 0.005 0 0.0027 66.85
Drive cycle CO2 CO THC NOX PM Fuel
cons. g/km g/km g/km g/km g/km g/km Cold ECE 323.3 0.422 0.011 0.006 0.0071 106.16 Cold EUDC
181.9 0.187 0.005 0.004 0.0042 59.70
Vehicle 3 Fiat (Punto) running on base gasoline fuel. Drive cycle CO2 CO THC NOX PM Fuel
cons. g/km g/km g/km g/km g/km g/km Cold ECE 200.6 4.891 0.447 0.211 0.0056 66.12 Cold EUDC
125.2 0.262 0.016 0.011 0.0005 39.63
Vehicle 3 Fiat (Punto) running on E10 fuel. Drive cycle CO2 CO THC NOX PM Fuel cons. g/km g/km g/km g/km g/km g/km Cold ECE 191.0 4.157 0.402 0.217 0.0029 65.14 Cold EUDC
110.1 0.190 0.011 0.010 0 36.18
Vehicle 4 Volkswagen (Golf) running on base gasoline fuel. Drive cycle CO2 CO THC NOX PM Fuel cons. g/km g/km g/km g/km g/km g/km Cold ECE 246.0 0.983 0.183 0.087 0.0202 78.24 Cold EUDC
132.2 0.059 0.004 0.006 0.0046 41.73
Page 108
Vehicle 4 Volkswagen (Golf) running on E10 fuel. Drive cycle CO2 CO THC NOX PM Fuel
cons. g/km g/km g/km g/km g/km g/km Cold ECE 226.5 0.773 0.135 0.095 0.0008 74.75 Cold EUDC
127.8 0.039 0.004 0.010 0.0011 41.89
Vehicle 5 Rover (416) running on base gasoline fuel. Drive cycle CO2 CO THC NOX PM Fuel
cons. g/km g/km g/km g/km g/km g/km Cold ECE 250.6 8.246 0.604 0.422 0.0056 83.68 Cold EUDC
147.5 0.373 0.020 0.255 0.0036 46.70
Vehicle 5 Rover (416) running on E10 fuel Drive cycle CO2 CO THC NOX PM Fuel
cons. g/km g/km g/km g/km g/km g/km Cold ECE 256.2 7.509 0.525 0.450 0.0074 88.35 Cold EUDC
146.2 0.841 0.026 0.302 0.0009 48.38
Table A7. Summary of FTIR emissions measurements for vehicles 4, 5 and 6 Vehicle 6 Toyota (Yaris) (repeat)) running on base gasoline fuel. Drive cycle
Methane 1,3-butadiene
Formaldehyde Acetaldehyde Nitrous oxide
Benzene
mg/km mg/km mg/km mg/km mg/km mg/km Cold ECE 79.593 3.007 0.974 9.042 0.660 N/D* Cold EUDC
13.173 0.326 0.288 1.003 0.095 3.124
Vehicle 6 Toyota Yaris (repeat), running on E10 fuel Drive cycle
Methane 1,3-butadiene
Formaldehyde Acetaldehyde Nitrous oxide
Benzene
mg/km mg/km mg/km mg/km mg/km mg/km Cold ECE 92.031 1.307 0.509 18.183 0.198 10.092 Cold EUDC
11.640 0.231 0.197 0.896 0.014 1.347
Vehicle 4 Volkswagen (Golf) running on base gasoline fuel. Drive cycle
Methane 1,3-butadiene
Formaldehyde Acetaldehyde Nitrous oxide
Benzene
mg/km mg/km mg/km mg/km mg/km mg/km Cold ECE 13.009 1.739 0.079 1.619 0.012 N/D* Cold EUDC
0.602 0.104 0.009 0.078 0.004 0.003
Page 109
Vehicle 4 Volkswagen (Golf) running on E10 fuel. Drive cycle
Methane 1,3-butadiene
Formaldehyde Acetaldehyde Nitrous oxide
Benzene
mg/km mg/km mg/km mg/km mg/km mg/km Cold ECE 11.977 1.120 0.074 4.365 0.388 N/D* Cold EUDC
0.655 0.076 0.031 0.163 0.001 N/D*
Vehicle 5 Rover (416) running on base gasoline fuel. Drive cycle
Methane 1,3-butadiene
Formaldehyde Acetaldehyde Nitrous oxide
Benzene
mg/km mg/km mg/km mg/km mg/km mg/km Cold ECE 69.302 4.011 0.220 13.846 N/D* N/D* Cold EUDC
11.260 0.183 0.124 1.225 N/D* N/D*
Vehicle 5 Rover (416) running on E10 fuel Drive cycle Methane 1,3-
butadiene Formaldehyde
Acetaldehyde
Nitrous oxide
Benzene
mg/km mg/km mg/km mg/km mg/km mg/km Cold ECE 50.244 2.334 0.107 12.660 N/D* N/D* Cold EUDC
7.247 0.107 0.039 1.408 0.007 N/D*
* No data presented. Table A8. Summary 2 of FTIR emissions measurements for vehicles 4, 5 and 6 Vehicle 6 Toyota (Yaris, repeat) running on base gasoline fuel. Drive cycle Benzene Ammonia Formaldehyde Acetaldehyde Total
PAHs mg/km mg/km mg/km mg/km µg/km Cold ECE+EUDC
0.124 4.001 0.667 0.200 43.62*
Vehicle 6 Toyota (Yaris, repeat) running on E10 fuel Drive cycle Benzene Ammonia Formaldehyde Acetaldehyde Total
PAHs mg/km mg/km mg/km mg/km µg/km Cold ECE+EUDC
0.057 5.232 0.401 0.654 44.86*
Vehicle 4 Volkswagen (Golf) running on base gasoline fuel. Drive cycle Benzene Ammonia Formaldehyde Acetaldehyde Total PAHs mg/km mg/km mg/km mg/km µg/km Cold ECE+EUDC
0.347 4.567 0.114 0.049 113.71*
Page 110
Vehicle 4 Volkswagen (Golf) running on E10 fuel Drive cycle Benzene Ammonia Formaldehyde Acetaldehyde Total PAHs mg/km mg/km mg/km mg/km µg/km Cold ECE+EUDC
0.056 2.755 0.072 0.178 30.22 *
Vehicle 5 Rover (416) running on base gasoline fuel. Drive cycle Benzene Ammonia Formaldehyde Acetaldehyde Total PAHs mg/km mg/km mg/km mg/km µg/km Cold ECE+EUDC
0.357 7.788 0.214 0.532 42.57*
Vehicle 5 Rover (416) running on E10 fuel Drive cycle Benzene Ammonia Formaldehyde Acetaldehyde Total PAHs mg/km mg/km mg/km mg/km µg/km Cold ECE+EUDC
1.818 18.826 1.298 1.493 66.17*
* Average value for Cold ECE+EUDC and the following driving cycles: WSL Congested, WSL Urban,
Page 111
15. APPENDIX 2
15.1. Evaporation Test of Two Ethanol Blended RON 95 Summer Gasolines
Separate report from AVL MTC AB.
Evaporation Test of Two Ethanol Blended RON 95
Summer Gasolines
Magnus Henke
2005-04-29
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 2 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
2
TABLE OF CONTENTS 1 Summary ......................................................................................................................................... 3 2 Introduction ..................................................................................................................................... 4 3 Experimental ................................................................................................................................... 5
3.1 Test Facilities ......................................................................................................................... 5 3.2 Testing equipment.................................................................................................................. 5 3.3 Fuels....................................................................................................................................... 6
3.3.1 Specifications..................................................................................................................... 6 3.4 Blending & Storage................................................................................................................ 8 3.5 Test procedure........................................................................................................................ 8
3.5.1 Conditioning: ..................................................................................................................... 8 3.5.2 Test procedure in the VT shed........................................................................................... 8 3.5.3 Purging of the VT shed...................................................................................................... 9
3.6 Calibration ............................................................................................................................. 9 4 Results ........................................................................................................................................... 10
4.1 Changes over time in Hydrocarbon levels (FID).’............................................................... 10 4.2 Changes over time for other components (MS).’................................................................. 11
4.2.1 Ethanol............................................................................................................................. 11 4.2.2 Butane.............................................................................................................................. 12 4.2.3 Benzene ........................................................................................................................... 13 4.2.4 Toluene and Xylene......................................................................................................... 14 4.2.5 MTBE .............................................................................................................................. 15
4.3 Comparison of final values, Bar graphs............................................................................... 16 4.4 Vapour pressure analyses..................................................................................................... 19
5 Indexes .......................................................................................................................................... 20 5.1 List of Pictures ..................................................................................................................... 20 5.2 List of Figures and charts..................................................................................................... 20 5.3 List of Tables ....................................................................................................................... 20 5.4 List of Bar graphs................................................................................................................. 20
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 3 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
3
1 SUMMARY The evaporative emissions from two summer gasoline fuels (with Reid Vapour Pressures, RVPs, of 63 kPa and 70 kPa, respectively) blended with low percentages of ethanol (0%, 5%, 10% and 15%) have been measured in a VT Shed. For reference purposes E85 (85% ethanol) was also measured in the same manner. In the tests, a half-filled container prepared with an opening for the gaseous compounds to pass through was placed on its side in the shed at an ambient temperature of 45 ºC. Each fuel was stabilized at 0ºC at the beginning of the test and had a final temperature of about 40ºC. Total hydrocarbon (THC) emissions were monitored at appropriate intervals through the use of a Flame Ionization Detector (FID) installed in the VT Shed and a number of components of interest of the same test fuel were sampled throughout the tests with a mass spectrometer (MS). The FID data showed that evaporated THC levels ranged from 200 ppm for the unblended gasoline with the low (63 kPa) RVP, to 340 ppm for a 10% mix of ethanol in the high RVP (70 kPa) gasoline. Test results showed that the RVP rises sharply when ethanol is first added to the fuels and peaks at ethanol contents between 5 and 10% Butane was the main component that vaporized during the tests, as expected since the vapour pressure of commercially supplied gasoline is primarily adjusted to meet regulated standards by adjusting butane levels. The evaporation of ethanol was influenced both by its content in the tested blends and by the consequent changes in vapour pressure (RVP), and thus showed slightly different evaporation patterns from the other components. The addition of ethanol also caused the evaporation of all the remaining components to increase by approximately the same factors as the butane Evaporation from the blends with the high RVP (70 kPa) base gasoline was stronger than the evaporation from the gasoline with the lower RVP (63 kPa), although there was some overlap.
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 4 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
4
2 INTRODUCTION To meet the requirements of the European Directive designed to promote the use of biofuels (2003/30/EC) Sweden has to substantially increase the production or imports of renewable fuels. Legislation has to make it easier, and in some cases possible, to market and use these hybrid fuels. To meet these goals in a short time steps have to be taken to ensure that the introduced fuels are usable by the current vehicle fleet. The only plausible way to reach this goal is to increase the amount of these fuels blended in today’s conventional fuels. Previous experience suggests that alcohols should be added to gasoline for this purpose. Methanol and ethanol are the main alternative fuels that have been tested on a relatively large scale, both as blended and pure fuels. This report focuses on the use of ethanol. One problem related to the use of ethanol in gasoline is the increased vapour pressure caused by the alcohol when mixed in relatively low proportions with gasoline. Blends of around 10% are of particular concern today. In the study reported here, the partial vapour pressures of ethanol and selected components of gasoline were measured in tests with blends of two base gasolines (with Reid Vapour Pressures, RVP, of 63 kPa and 70 kPa, respectively) and ethanol contents of 0%, 5%, 10% and 15%.
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 5 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
5
3 EXPERIMENTAL
3.1 Test Facilities All tests were performed at AVL MTC in Haninge, Sweden, in February 2005. The AVL MTC Motor test centre is an accredited laboratory for automotive testing and has been in operation for approximately 15 years. AVL MTC has experience of more than 10 years of testing for the Swedish Environmental Protection Agency and the Swedish National Road Administration.
3.2 Testing equipment All tests were performed using a gas-proof test container (not the fuel container mentioned below) in which the evaporative behaviour of whole cars is normally tested. It is called a VT shed as both its volume and temperature are controlled. A standard component of this kind of equipment is a Flame Ionization Detector (FID) for measuring the total emitted hydrocarbons. This instrument, along with an Air Sense Mass Spectrometer, was used for the tests.
Picture 1 – VT Shed Container with Mass Spectrometer to the left
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 6 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
6
3.3 Fuels The base fuels used were identical mixtures, except for their contents of the Reid Vapour Pressure (RVP)-regulating compound butane, a larger quantity of which had been removed from the 63 kPa RVP fuel. Adjusting the RVP in this way is a standard procedure when commercially preparing gasoline that is to be blended with ethanol, to ensure that the vapour pressure of the final blend does not exceed specified limis.
3.3.1 Specifications
Table 1. Gasoline Certificate of Quality (RVP 63 kPa)
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 7 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
7
Table 2. Gasoline Certificate of Quality (RVP 70 kPa)
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 8 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
8
3.4 Blending & Storage The test fuels were blended by personnel with a very good understanding of the test and the difficulties associated with it. Particularly close attention was paid to obtaining a uniform start temperature and making sure that no fuel was exposed to temperatures that might cause early vaporization. Therefore blending was performed in an area conditioned to a maximum of 0ºC. For the same reason, the fuel was stored in the conditioned area until just before the test. On average the transportation and preparation of the previously blended fuel before the tests took only 3 min. By the time the test was started the temperature of the gasoline had risen on average by 1.5ºC.
3.5 Test procedure Each test consisted of three major parts:
• Conditioning the fuel and filling the test container. • The test procedure in the VT shed. • Purging the VT shed.
3.5.1 Conditioning:
The fuel was brought down to sub-zero temperatures before being poured into the special test container and taken into the test facility. In the test container the temperature of the fuel was monitored continuously. When the desired temperature was reached the container was taken into the VT shed and the test was started.
3.5.2 Test procedure in the VT shed
A specially prepared fuel container conditioned at 0ºC was placed in the container whilst the VT shed itself was set to maintain a steady 40ºC throughout the test. To make sure a uniform concentration was present throughout the entire volume of the VT shed, a small floor-mounted fan directed away from the fuel container acted as an “air mixer”. In the fuel container a small hole was drilled, which was plugged until the start of the test, when the container was set on its side, the hole was opened and a thermocouple was plugged in to monitor the fuel temperature during the test.
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 9 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
9
3.5.3 Purging of the VT shed
To ensure that the VT shed was rid of all residual vapour before a new test was started it had to be purged. This is a lengthy procedure which involves taking the shed to its maximum temperature for approximately an hour. A graph displaying changes in temperature over time of all the tested blends is presented below (Figure 1). The rising traces represent the fuel container temperature and the steady traces the VT shed air temperature.
Temperatures of the Fuels and Shed Cell Air During the tests
0
5
10
15
20
25
30
35
40
45
50
Time, 2 hrs
Deg
rees
Cel
cius
Air temp R63-0 Fuel temp R63-0
Air temp R63-5 Fuel temp R63-5
Fuel temp R63-10 Air temp R63-15
Fuel temp R63-15 Air temp R70-0
Fuel temp R70-0 Air temp R70-5
Fuel temp R70-5 Air temp R70-10
Fuel temp R70-10 Air temp R70-15
Fuel temp R70-15 Air temp R63-85
Fuel temp R63-85 Air temp R63-10
Start temp of Fuel = 3 deg C
VT Shed Cell Air Temperat re
Figure 1 Temperature of the Fuels and VT Shed cell Air during the tests
3.6 Calibration
Both of the instruments used for measuring (the FID and MS) during this project were calibrated using certified pre-mixed gases to ensure quality. All calibration gases were delivered by Air Liquide and traceable in accordance to the standard of NIST.
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 10 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
10
4 RESULTS Changes over time in the air levels of the measured constituents as the tests progressed are here presented in chart form to facilitate interpretation of the measurements. The final concentrations at the end of the tests are also presented in bar graph format at the end of this report to facilitate comparisons.
4.1 Changes over time in Hydrocarbon levels (FID).’
Concentration of total HC (FID analyzer) during 2 hrs of testing
0
50
100
150
200
250
300
350
400
Time, 2 hrs
Con
cent
ratio
n of
tot H
C, p
pm
R63-0
R63-5
R63-10
R63-15
R70-0
R70-5
R70-10
R70-15
E85
RVP 70 (0-15% Eth)
RVP 63 (0-15%
E85
Figure 2 Changes over time in Total Hydrocarbon Concentration (FID) in the VT Shed
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 11 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
11
4.2 Changes over time for other components (MS).
4.2.1 Ethanol
Unsurprisingly, the ethanol content of the vapour proved to increase with increasing ethanol content in the test container to some extent. However, the relationship was not linear. Two factors contribute to this pattern. Naturally, the vapour pressure is positively correlated to the ethanol content of the blend in the container. In addition, however, ethanol enhances the vapour pressure according to a relationship that is not linear and peaks at relatively low ethanol contents of around 10% in ethanol-gasoline blends. This is shown here since the vapour contents (ppm) were virtually the same for both the 5% and 10% blends, while those of both the 0% and the E85 blends were considerably lower.
Concentration of Ethanol in Shed during 2 hrs of testing
0,0
2,0
4,0
6,0
8,0
10,0
12,0
14,0
16,0
18,0
20,0
22,0
Time, 2hrs
Con
cent
ratio
n, p
pm e
than
ol
Ethanol (fl.avg.) 63-0 C2H5OH-45
Ethanol (fl.avg.) 63-5 C2H5OH-45
Ethanol (fl.avg.) 63-10 C2H5OH-45
Ethanol (fl.avg.) 63-15 C2H5OH-45
Ethanol (fl.avg.) 70-0 C2H5OH-45
Ethanol (fl.avg.) 70-5 C2H5OH-45
Ethanol (fl.avg.) 70-10 C2H5OH-45
Ethanol (fl.avg.) 70-15 C2H5OH-45
Ethanol (fl.avg.) E85
Poly. (Ethanol (fl.avg.) E85)
RVP63-0, RVP70-0
E85
RVP63 (5-15)
RVP70 (5-15)
Figure 3 Changes over time in the Ethanol Concentration in the VT Shed
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 12 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
12
4.2.2 Butane
Butane is the main compound used to regulate the vapour pressure of gasoline. It is removed to reduce the vapour pressure when required, for instance in summer gasoline, which is used in higher ambient temperature ranges. The gasoline with the higher Reid Vapour Pressure (RVP) index was therefore expected to have a higher content of vaporizing butane. This expectation was confirmed in the tests, as shown below. In addition, the butane vapour pressure-enhancing effect of the ethanol blended in the base gasolines was probably maximal at contents between 5 and 10%.’?
Concentration of Butane in Shed during 2hrs of testing
0,0
20,0
40,0
60,0
80,0
100,0
120,0
140,0
Time, 2 hrs
Con
cent
ratio
n of
but
hane
, ppm
Butane (fl.avg.) 63-0
Butane (fl.avg.) 63-5
Butane (fl.avg.) 63-10
Butane (fl.avg.) 63-15
Butane (fl.avg.) 70-0
Butane (fl.avg.) 70-5
Butane (fl.avg.) 70-10
Butane (fl.avg.) 70-15
Butane (fl.avg.) E85
Poly. (Butane (fl.avg.) E85)
Poly. (Butane (fl.avg.) 63-0)
E85
RVP 70-5%RVP 70-10%RVP 70-15%RVP 70-0%
RVP 63-5%RVP 63-10%RVP 63-15%RVP 63-0%
Figure 4 Changes over time in the Butane Concentration in the VT Shed
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 13 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
13
4.2.3 Benzene
Benzene is an aromatic hydrocarbon with both ozone formation and carcinogenic potential, so its emission levels are strictly restricted. Aromatics, however, are widely used to substitute lead as an anti-knock compound in gasoline. Benzene is also created during the combustion process in engines.
Concentration of Benzene in Shed during 2hrs of testingApproximately a 20% maximum concentration increase, (E5)
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
0,45
0,50
0,55
0,60
0,65
0,70
Time, 2hrs
Con
cent
ratio
n of
Ben
zene
, ppm
Benzene (fl.avg.) 63-0 C6H6-78
Benzene (fl.avg.) 63-5 C6H6-78
Benzene (fl.avg.) 63-10 C6H6-78
Benzene (fl.avg.) 63-15 C6H6-78
Benzene (fl.avg.) 70-0 C6H6-78
Benzene (fl.avg.) 70-5 C6H6-78
Benzene (fl.avg.) 70-10 C6H6-78
Benzene (fl.avg.) 70-15 C6H6-78
Benzene (fl.avg.) E85
Poly. (Benzene (fl.avg.) E85)
E85
RVP 70-5 (max)RVP 70-0RVP 63-5RVP 63-0
Figure 5 Changes over Time in the Benzene Concentration in the VT Shed Max concentration increase compared to base levels: approx. 20% (with E5)’.
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 14 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
14
4.2.4 Toluene and Xylene
Concentration of Toluene in Shed during 2hrs of testingApproximately a 20% maximum concentration increase, (E5)
0,0
0,5
1,0
1,5
2,0
2,5
3,0
Time, 2hrs
Con
cent
ratio
n of
Tol
uene
, ppm
Toluene (fl.avg.) 63-0 C7H8-92Toluene (fl.avg.) 63-5 C7H8-92Toluene (fl.avg.) 63-10 C7H8-92Toluene (fl.avg.) 63-15 C7H8-92Toluene (fl.avg.) 70-0 C7H8-92Toluene (fl.avg.) 70-5 C7H8-92Toluene (fl.avg.) 70-10 C7H8-92Toluene (fl.avg.) 70-15 C7H8-92Toluene (fl.avg.) E85Poly. (Toluene (fl.avg.) E85)
Figure 6 Changes over Time in the Toluene Concentration in the VT Shed
Concentration of Xylene in Shed during 2hrs of testing
0,0
0,2
0,4
0,6
0,8
1,0
1,2
Time, 2hrs
Con
cent
ratio
n of
Xyl
ene,
ppm
Xylene (fl.avg.) 63-0 o-C8H10-106
Xylene (fl.avg.) 63-5 o-C8H10-106
Xylene (fl.avg.) 63-10 o-C8H10-106
Xylene (fl.avg.) 63-15 o-C8H10-106
Xylene (fl.avg.) 70-0 o-C8H10-106
Xylene (fl.avg.) 70-5 o-C8H10-106
Xylene (fl.avg.) 70-10 o-C8H10-106
Xylene (fl.avg.) 70-15 o-C8H10-106
Xylene (fl.avg.) E85
Poly. (Xylene (fl.avg.) E85)
Figure 7 Changes over Time in the Xylene Concentration in the VT Shed Max concentration increase compared to base levels: approx. 20% (with E5)
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 15 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
15
4.2.5 MTBE
Concentration of MTBE in Shed during 2hrs of testing
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
Time, 2 hrs
Con
cent
ratio
n of
MTB
E, p
pm
MTBE (fl.avg.) 63-0 MTBE
MTBE (fl.avg.) 63-5 MTBE
MTBE (fl.avg.) 63-10 MTBE
MTBE (fl.avg.) 63-15 MTBE
MTBE (fl.avg.) 70-0 MTBE
MTBE (fl.avg.) 70-5 MTBE
MTBE (fl.avg.) 70-10 MTBE
MTBE (fl.avg.) 70-15 MTBE
MTBE (fl.avg.) E85
Poly. (MTBE (fl.avg.) E85)
Figure 8 Changes over Time in the MTBE Concentration in the VT Shed Max concentration increase compared to base levels: approx. 20% (with E5)’
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 16 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
16
4.3 Comparison of final values, Bar graphs The concentrations of the measured emissions from E85 are included as a separate series since we have no information on the vapour pressure of the base gasoline used for blending. However, it probably has a relatively high RVP since this level of ethanol lowers the Reid Vapour Pressure of the final mix.
Ethanol Concentration at the end of the test
0
5
10
15
20
25
0% 5% 10% 15% E85
Blend of Ethanol
Ethanol RVP63
Ethanol RVP70
Ethanol E85
Bar graph 1. Ethanol concentration at the end of the test (ppm)
Butane Concentration at the end of the test
0
20
40
60
80
100
120
140
0% 5% 10% 15% E85
Blend of Ethanol
Butane RVP63
Butane RVP70
Butane E85
Bar graph 2. Butane concentration at the end of the test (ppm)
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 17 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
17
Benzene Concentration at the end of the test
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0% 5% 10% 15% E85
Blend of Ethanol
Benzene RVP63
Benzene RVP70
Benzene E85
Bar graph 3. Benzene concentration at the end of the test (ppm)**
Toluene Concentration at the end of the test
0
0,5
1
1,5
2
2,5
3
0% 5% 10% 15% E85
Blend of Ethanol
Toluene RVP63
Toluene RVP70
Toluene E85
Bar graph 4. Toluene concentration at the end of the test (ppm)
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 18 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
18
Xylene Concentration at the end of the test
0
0,2
0,4
0,6
0,8
1
1,2
1,4
0% 5% 10% 15% E85
Blend of Ethanol
Xylene RVP63
Xylene RVP70
Xylene E85
Bar graph 5. Xylene concentration at the end of the test (ppm)
MTBE Concentration at the end of the test
00,050,1
0,150,2
0,250,3
0,350,4
0% 5% 10% 15% E85
Blend of Ethanol
MTBE RVP63
MTBE RVP70
MTBE E85
Bar graph 6. MTBE concentration at the end of the test (ppm)
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 19 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
19
4.4 Vapour pressure analyses A small amount of each of the gasoline and ethanol blends was sampled and sent for analysis to Saybolt Co. The results are shown in Bar graph 7. The samples were packed in gas-proof containers, provided by the company, to prevent any components escaping and thus changing the properties of the sample before analysis.
Vapour pressure as analysed by Saybolt
0102030405060708090
100
0% 5% 10% 15% E85
Rei
d Va
por P
ress
ure
(RVP
), kP
a
RVP 63RVP 70E85
Bar graph 7. Results from the Reid Vapour Pressure analyses by Saybolt
MTC-AA-0024 Rev. 4
Prepared Magnus Henke
Date – Rev 2004-07-13
Document - Ref Report <2005-05-30> <1>
Page 20 (20)
AVL MTC Armaturvägen 1, P.O. Box 223, SE-136 23 Haninge. Tel 08-500 656 00
20
5 INDEXES
5.1 List of Pictures Picture 1 – VT Shed Container with Mass Spectrometer to the left........................................................ 5
5.2 List of Figures and charts Figure 1 Temperature of the Fuels and VT Shed cell Air during the tests.............................................. 9 Figure 2 Changes over time in Total Hydrocarbon Concentration (FID) in the VT Shed .................... 10 Figure 3 Changes over time in the Ethanol Concentration in the VT Shed .......................................... 11 Figure 4 Changes over time in the Butane Concentration in the VT Shed ........................................... 12 Figure 5 Changes over Time in the Benzene Concentration in the VT Shed........................................ 13 Figure 6 Changes over Time in the Toluene Concentration in the VT Shed ........................................ 14 Figure 7 Changes over Time in the Xylene Concentration in the VT Shed .......................................... 14 Figure 8 Changes over Time in the MTBE Concentration in the VT Shed .......................................... 15
5.3 List of Tables Table 1. Gasoline Certificate of Quality (RVP 63 kPa) .......................................................................... 6 Table 2. Gasoline Certificate of Quality (RVP 70 kPa) .......................................................................... 7
5.4 List of Bar graphs Bar graph 1. Ethanol concentration at the end of the test (ppm) ........................................................... 16 Bar graph 2. Butane concentration at the end of the test (ppm) ............................................................ 16 Bar graph 3. Benzene concentration at the end of the test (ppm)**...................................................... 17 Bar graph 4. Toluene concentration at the end of the test (ppm) .......................................................... 17 Bar graph 5. Xylene concentration at the end of the test (ppm)............................................................ 18 Bar graph 6. MTBE concentration at the end of the test (ppm) ............................................................ 18 Bar graph 7. Results from the Reid Vapour Pressure analyses by Saybolt ........................................... 19
