› vehiclesandfuels › pdfs › merit_review_2011 › ... · Quality, Performance, and Emission Impacts of Biofuels and …Samples generally met the requirements of ASTM D7467,

NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

Quality, Performance, and Emission Impacts of Biofuels and Biofuel Blends

Vehicle Technologies Program MeritReview - Fuels and LubricantsTechnologies

Bob McCormick

May 10, 2011Washington, DC

Project ID: FT003

This presentation does not contain any proprietary, confidential, or otherwise restricted information

NATIONAL RENEWABLE ENERGY LABORATORY

Team MembersTeresa Alleman

Jon BurtonEarl Christensen

Gina ChupkaWendy ClarkLisa Fouts

Xin HeKeith Knoll

Mike LammertJon Luecke

Barbara MyersMatt Ratcliff

Matt ThorntonAaron WilliamsJanet Yanowitz

2


OverviewTimelineStart date: Oct 2010End date: Sept 2011Percent complete: 66%Program funded one year at a time

BarriersVTP MYPP Fuels & Lubricants Technologies Goals• By 2013 identify LD non-petroleum

based fuels that can achieve 10% petroleum displacement by 2025

• By 2015 identify HD non-petroleum based fuels that can achieve 15% petroleum displacement by 2030

3

BudgetTotal project fundingFY10: $1.8 MFY11: $1.6 M – estimatedNBB CRADA provides around $750Kper year to cost share biodiesel research

Partners• National Biodiesel Board and member

companies• Manufacturers of Emission Controls

Association and member companies• Engine Manufacturers Association® and

member companies• Coordinating Research Council® and

member companies• Colorado School of Mines• Oak Ridge National Laboratory• State of Colorado


Relevance

4

Objective: Solve technical problems that are preventing expanded markets for current and future biofuels and biofuel blends

Necessary to achieve MYPP petroleum displacement goals and RFS requirementsGoals are solving problems for current biofuels and early identification of problems for future/proposed biofuels – valuable information for planning future R&D

1. Biofuel quality:– Need for ASTM standards to help ensure quality in the market place

– Need for new and improved test methods for biofuels and blends

– Storage stability and handling issues for new fuels are unknown

– Low‐temperature operability for new diesel fuels has not been researched

2. Inadequate information on engine durability and emission control equipment:– Effect of biofuel and impurities on materials and catalysts

– Impacts on lube oil performance are poorly quantified

4. Poor understanding of air quality impacts:– No emission data for newer technology engines

– Limited data on toxic compound and PN emission effects


Approach/Strategy

5

• Examining the broad scope of biofuels, from ethanol and biodiesel to next generation oxygenate and hydrocarbons

• High level screening of new biofuels – future work requiring more detailed study will depend on results

• Measure quality and performance properties, compatibility with engines, lubricants, and emission controls; and impacts on emissions

• Research projects in many different areas: chemical analysis, storage stability, low-temperature operability, volatility, materials compatibility, impurity effects, and emissions

• Statistical analysis of results, and thermophysical property modeling of low-temperature performance and volatility

• Industry collaborations guide our work to be relevant, while collaborations with other labs and universities broaden our effective capability


Milestones

6

Month/Year MilestoneJun-10 Wintertime Biodiesel Blend Quality Survey. Forty Bxx blends from public pumps around the

United States. Samples generally met the requirements of ASTM D7467, the specification for B6 to B20blends, however 22% failed for oxidation stability.

Jun-10 Biodiesel Ash Impacts on DPF Durability. An accelerated test was used to assess how Na, K, and Ca that may be present in B20 affect durability of 3 different DPFs. The results showed no degradation in the thermal shock resistance of a cordierite DPF after exposure to 150,000 miles of biodiesel ash.

Sep-10 Biodiesel Effects on PM Size/Number Emissions. An FMPS instrument was applied to measure the impact of biodiesel, ULSD, and DPF on PM size number emissions.

Sep-10 Biodiesel Impact on Toxic Compound Emissions. A novel mass-spec ionization method that is specific for nitro-compounds was employed to measure the impact of biodiesel, ULSD, and DPF on nitro-PAH and other emissions. Blending of biodiesel generally reduced these emissions.

Nov-10 Effect of saturated monoglycerides on biodiesel low-temperature performance. A study showing how saturated monoglycerides can negatively impact biodiesel cold weather performance was published.

Mar-11 Ethanol Blender Pump Fuel Quality Survey. Fifteen blender pump stations were sampled in July 2010. Conventional gasoline, FFV Fuel, and the two lowest blends were collected. Fuel properties were compared to the D4814 and D5798 specifications.

Apr-11 Properties of gasoline/oxygenate blends. Experimental study assessing the properties of individual C2-C5 alcohols plus several cellulose derived oxygenates blended into summer, winter, and shoulder season BOBs.

May-11 Impact of pre-oxidation on the stability of B100. Experiments assessing the actual stability of poor stability B100 that is brought into spec by blending with AO or stable B100

Aug-11 Impact of biodiesel ash forming constituents on SCR catalyst performance. Effects of Na and K on both LD and HD configurations are being measured in accelerated tests.


List of Technical Accomplishments

7

1. B20 DOC/DPF/SCR Durability Research2. Saturated Monoglyceride Effects on Biodiesel Low-

Temperature Performance3. Properties of Biomass-Derived Oxygenate-Gasoline Blends4. Levulinic Acid Esters as Diesel Blend Components5. FFV Emissions with Blender Pump or Co-Mingled Fuels -

ongoing6. Initiated measurement of biodiesel lube oil dilution in both

LD and HD systems with active regeneration - ongoing7. 2009/2010 Winter Biodiesel Blend Survey8. Ethanol Blender Pump Survey9. Developed 2-D GC method for measuring biodiesel and diesel

fuel dilution in lube10. Emission Testing of B20 in Transit Buses - ongoing11. PM Size/Number Emissions12. New Analytical Methods for Impurities in Fuel and Toxics

Emissions - ongoing

Presented Today

See Technical Backup Slides


Technical Accomplishment:

8

B20 DOC/DPF/SCRDurability Research

Test engine donated by Caterpillar®

Catalyst parts donated by MECA

Total Ash Exposure for B20 at ASTM limits150k miles ~ 232 grams (77 hr)

435k miles ~ 674 grams (222 hr)

• Do metals at current limits impact performance or durability?

• 5 ppm max Na+K and 5 ppm max Ca+Mg

• Accelerated method for exposing emissions control devices to 435k miles of biodiesel ash

• Doping fuel with 7 ppm K, 21 ppm Na, and 24 ppm Ca accelerates ash exposure

• Test cycle simulates DPFtime/temperature history


Technical Accomplishment: B20 Impact on DOC and DPF

9

• DOC activity measured at simulated 150k miles• No change in CO conversion• 7% reduction in HC conversion• 8% reduction in NO2:NOx ratio

• Inlet section for B20 DOC showed signs of washcoat cracking• 1% Na in the washcoat of inlet section

• DPF at 150k miles shows <1 kPabackpressure increase• Cordierite showed no change in thermal shock resistance parameter

• DPF operated to 435k miles shows 3 kPa backpressure increase• No ash cleaning at 150k mile intervals• Thermal shock resistance parameter reduced by 69%

NO2


Technical Accomplishment: B20 Impact on SCR Activity

10

• SCR tested in HD configuration (DOC‐DPF‐SCR)• Catalysts emission tested on HDT after simulated 435k mile exposure• Biodiesel aged catalysts experienced significant deactivation

• FUL at specification limit• Potentially caused by alkali metal salt volatilization from DPF

• Potassium salts more volatile than sodium – but K methoxiderarely used in biodiesel production

• Ongoing follow up examining Na and K separately• LD (SCR‐DPF) and HD (DPF‐SCR)

Williams and others, SAE 2011-01-1136

Industry partners: Caterpillar, Ford, NBB, Umicore, BASF Catalysts LLC, MECA, EMA

Final emission testing conducted at BASF



11

Ideal solution model predicts SMG affect on CP• A single component precipitates at the CP• The melting point (Tm), heat of melting (ΔHm) and concentration of component (x) determine the CP for the solution

High final melting point observed in real-world diesel causing dispenser filter clogging

Saturated Monoglyceride Effects on Biodiesel Low-Temperature Performance

Biodiesel, Volume Percent

0 5 10 15 20

Fina

l Mel

ting

Poin

t, o C

-50

-40

-30

-20

-10

0

10

20

30

CO Pump Diesel Low SMGCO Pump Diesel High SMG10% Aro CARB Diesel Low SMG10% Aro CARB Diesel High SMG37% Aro Diesel Low SMG37% Aro Diesel High SMGMN No. 1 Diesel Low SMGMN No. 1 Diesel High SMG

Diesel fuel properties shown to have significant effect on SMG solubility temperature


Making Oxygenates from Biomass

12

• Biomass has a high oxygen content• O/C molar ratio of 0.6

• Hydrocarbons may be preferred… but the most economical approach may prove to be oxygenates

• Alcohols from various approaches:• Gasification/syngas conversion

($1.85/gal ethanol projected)• Biochemical plus fermentation

• Oxygenates from acid hydrolysis and upgrading:

• Levulinc acid esters (15¢/lb projected)

• MTHF• Pentanoate esters

• We are taking a very high level look at performance properties and emission impacts



13

Oxygenate-Gasoline Water Interaction

2.5 ml DI water

25 ml Gasoline (BOB) + Alcohol at 3.7% Oxygen

Ethanol

1-propanol

2-propanol

1-butanol

2-butanol

i-butanol

1-pentanol

i-pentanol

Ethyl levulinate

Butyl levulinateMTHF

Methyl pentanoate

Wei

ght P

erce

nt O

xyge

n

1.5

2.0

2.5

3.0

3.5

4.0

Alcohols: 3.7% Oxygen in Gasoline Initially

Others: 2.7% Oxygen in Gasoline Initially

AlcoholsOther Oxygenates

•C2 to C5 alcohols blended in gasoline at 3.7 wt% oxygen• Level allowed by EPA waivers to the substantially similar rule

•Other oxygenates blended at 2.7% oxygen• MTHF (an aliphatic ether) allowed by subsim rule, other oxygenates

are not subsimCompound Boiling

Point (°C) Gasoline 27-225 Ethanol 78 1-Propanol 97.2 2-Propanol 82.3 1-Butanol 117.7 i-Butanol 107.9 2-Butanol 99.6 1-Pentanol 137.8 i-Pentanol 132 MTHF 78 Ethyl levulinate 206 Butyl levulinate 237.5 Methyl pentanoate 126

Blendstocks kindly supplied by BP


D86

Dis

tilla

tion

End

Poin

t, o C

190

200

210

220

230

240Gas 1Gas 2Gas 3225oC Maximum

EL BL

Ant

ikno

ck In

dex

(R+M

/2)

82

84

86

88

90

92

94

Gas 1Gas 2Gas 387 Minimum

EL BL

Blending RON/MON:• EL=106/102• BL=98/96

Volume Percent Oxygenate

0 5 10 15 20

Ant

i-Kno

ck In

dex

(R+M

/2)

81

82

83

84

85

86

87

88

isopropanol1-propanol1-butanol2-butanolisobutanol1-pentanolisopentanolethanol87 Minimum

Volume Percent Oxygenate

0 5 10 15 20

Vapo

r Pre

ssur

e, k

Pa

70

75

80

85

90 Winter BOB

Oxygenate Effects on Performance Properties

6% 7.3%

Levulinate Esters

NATIONAL RENEWABLE ENERGY LABORATORY 14



15

Levulinic Acid Esters as Diesel Components

• Ethyl ester poorly soluble in diesel fuel, up to 8% can be extracted into water

• Butyl ester was soluble and had no effect on cloud point, very little extracted into water

• Enhanced both lubricity and conductivity

• Require cetane additive (2-ethyl hexylnitrate) – 0.79 v/v% in ester

• Emission testing in 2008 MY Cummins ISB over HDT• Large reduction in PM – high oxygen content• NOx effect inconsistent, likely because of

cetane enhancer• Use of these esters as diesel blend

components seems challenging

Perc

ent C

hang

e ve

rsus

Cer

tific

atio

n U

LSD

-60

-50

-40

-30

-20

-10

0

10

20

NOx Fuel ConsumptionEngine Out Smoke

EL10 BL20

Temperature, oC

-15 -10 -5 0 5 10 15

Volu

me

of S

epar

ate

Liqu

id P

hase

, ml

0.0

0.5

1.0

1.5

2.0

2.510% EL in No. 1 Diesel 10% EL in No. 2 Diesel10% EL in Certification Diesel

50 ml total volume

Industry partners: Mead-Westvaco Corporation and Trenton Fuel Works, LLC


Collaboration and Coordination with Other Institutions

16

B20 DOC/DPF/SCR Durability Research– MECA and member companies

• Umicore• BASF Catalysts, LLC

– Caterpillar– Ford– NBB (cofunding)– EMA and member companies– ORNL

Saturated Monoglyceride Effects on Biodiesel Low-Temperature Performance– NBB and member companies (cofunding)

Properties of Biomass-Derived Oxygenate-Gasoline Blends– National Bioenergy Center (NREL)

Levulinic Acid Esters as Diesel Blend Components– Mead Westvaco– Trenton Fuel Works

FFV Emissions with Blender Pump or Co-Mingled Fuels– State of Colorado (cofunding)

2009/2010 Winter Biodiesel Blend Survey– NBB and member companies

Ethanol Blender Pump Survey– CRC and member companies (cofunding)

New Analytical Methods for Impurities in Fuel and Toxics Emissions– Colorado School of Mines

Proposed Future WorkB20 DOC/DPF/SCR Durability Research

Impacts of Na and K separatelyMetals effects for LD and HD configurations

Biodiesel Low-Temperature PerformanceEffect of mixed saturated and unsaturated monoglycerides, water, and other impuritiesDiesel fuel property effects on SMG solubility

Biomass-Derived Oxygenate-Gasoline BlendsAssess gasoline blend properties for viability of oxygenatesBasic emission testing for viable oxygenatesMixed-alcohols similar to OBP thermochemical platform

FFV Emissions with Blender Pump FuelsComplete emission testing of 6 additional FFVs

Biodiesel Lube Oil DilutionComplete analysis of HD lube oil samplesMeasurement of LD lube oil dilution study using MAD

2011 B100 Quality Survey – including detailed analysis of impurities present

Emission Testing of B20 in Transit BusesTest 2 additional buses

Fuel Butanol ASTM Standard – support development at ASTM

Plan significant expansion of thermodynamic modeling of phase equilibrium:•Volatility of metal salts in emission control equipment•Precipitation of solids in fuel at cold temperature•Vapor pressure and distillation of oxygenate gasoline blends

Oxygenate Mole Fraction

0.0 0.2 0.4 0.6 0.8 1.0

Vapo

r Pre

ssur

e, k

Pa

0

10

20

30

40

50

60

70

2-propanol measured 2-propanol model 1-butanol measured 1-butanol model 2-butanol measured 2-butanol model



Summary

18

• Guidance from last years AMR has improved the quality of the NREL NPBFL activity

• Studies of how biodiesel impurities impact engine and catalyst performance, as well as quality surveys, will expand markets for biodiesel

• Examination of biodiesel impacts on lube oil will provide industry with valuable information and serve as a template for future studies on lube oil compatibility with other fuels

• High level testing of a range of biomass-derived oxygenates will provide DOE and industry with guidance on viability of these fuels

• Research on high-level ethanol blends in FFVs will demonstrate the potential of this approach for petroleum displacement


Technical Backup Slides

19


Technical Accomplishment:Impetus:• Blender pump re‐fueling, even for properly functioning FFVs, may result in unintended increases in tailpipe emissions

• FFV algorithms were designed for E0/E10 or nominal E85 fueling. Blender pump fueling may result in loss of adaptive fuel:air control

Approach:• Collaborate with state of Colorado emissions lab – CDPHE to provide all vehicle testing and regulated emissions

• Include 9 FFVs from two model year groups (2001‐2006 / 2007‐current)Measure fully adapted emissions on E10 & E85

Measure hot start emissions following E40 “blender pump” fueling

Measure adapting & adapted emissions on E40

Status:• Three vehicle complete

• Next three vehicles procured – will begin test in March

• Three additional vehicles to be tested in May/June timeframe

Blender Pump Fuel Impacts on FFV Emissions


Emissions & Fuel Economy on LA92 Drive Cycle

Emissions Trends:

• One vehicle (’02 Minivan) exhibited poor adaptation following blender pump fueling with E40.

• Two vehicles (’02 Sedan and ’07 P/U) showed good adaptation to blender pump fueling with E40.

• Emissions followed expected trends with increasing ethanol: NMOG & CO both reduced NOX either reduced or flat aldehydes increased.

Fuel Economy:

• As reported elsewhere*, loss tracked slightly below energy content of fuel

• Potential influence variables: charge air cooling combustion efficiency spark advance

NMOG trends typical of other measured emissions

-30%

-25%

-20%

-15%

-10%

-5%

0%

10 20 30 40 50 60 70 80Ethanol Content (%)

%-D

rop

in F

uel E

nerg

y, V

eh M

PG

02 Sedan 02 Minivan07 Full-Size P/U Fuel Energy

Fuel Economy vs. Fuel Energy3-Phase Composite - LA92 Driving Cycle

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0 10 20 30 40 50 60 70 80Ethanol Content (%)

NM

OG

(g/m

ile)

'02 Minivan '02 Sedan '07 Full-Size P/U

'02 Minivan '02 Sedan '07 Full-Size P/U

After E40 fueling

from E10

Fully adapted on

E10

After E40 fueling

from E85

Fully adapted on

E85

Symbols w/o lines indicate hot start emissions immediately following re-fueling event (see refueling protocol)

* Ethanol - the primary renewable liquid fuel, Datta, et. al., J. Chem Technol Biotechnol, February 2011.


• Active DPF regeneration through post injection can result in fuel oil dilution

• Higher boiling point of biodiesel can increase propensity for lube oil dilution

• 2010 VW Jetta operated on mileage accumulation dyno for 4000 miles• B20 and ULSD• FTP72 (more frequent regen)• HWFET (less frequent regen)

• Lube oil samples collected at 400 mile intervals• Samples analyzed for fuel dilution, soot, TAN,

TBN, viscosity, wear metals and HFRR

2010 VW Jetta – 2.0L TDITier II Bin 5, DOC+DPF+LNT

Technical Accomplishment: Biodiesel Lube Oil Dilution



Technical Accomplishment: Wintertime B6-B20 Survey

AccomplishmentCompleted collection of 40 wintertime B6-B20 blends across US to assess quality at the pump, 75% of samples were from states with 10th percentile ambient temperature below -12 C.Significance•First biodiesel blend quality survey conducted since D7467, B6-B20 specification, was adopted.•Milestone due 6/30/10.•Continued problems with meeting oxidation stability.•Data might support lowering current AV specification.

– Enabled by improved detection limits in test method

– Strong desire from OEMs to have AV as low as possible

Biodiesel Contentvol% D7371

0 5 10 15 20 25 30

Aci

d N

umbe

r,m

gKO

H/g

D66

4

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Less than B6B6-B20 Greater than B20 AV Specification, Max = 0.3 mgKOH/g

Filled symbols are cold weather statesHollow symbols are warm weather states

Biodiesel Contentvol % D7371

0 5 10 15 20 25 30

Indu

ctio

n P

erio

d S

tabi

lity

hrs,

EN

1411

2

0

5

10

15

20

25Less than B6B6-B20Greater than B20Specification minimum = 6 hrs

Test stopped at 24 hrsFilled symbols are cold weather statesHollow symbols are warm weather states



24

Accomplishment•Collected samples from 15 stations in 8 states•Collaboration with CRCSignificance•First survey of blender pumps to assess quality – there is no specification for fuels with ethanol content above gasoline, but below E85•Collected base gasoline, E85, and 2 lowest blends offered (typically E20 and E30)•Gasolines varied from E0 to E10•E85 samples typically met the specification•Exx blends “looked” more like gasoline than E85 and would not meet the D5798-10 specification

Station

0 2 4 6 8 10 12 14 16

Eth

anol

con

tent

, vol

%, D

5501

or D

5599

0

20

40

60

80

100

Oxygenated gasolineE0 gasolineE20E30E50FFV Fuel

FFV FuelSpecificationLimits

MaximumEthanol Limitin Gasoline

Station ID

0 2 4 6 8 10 12 14 16

RV

P, p

si, D

5191

4

5

6

7

8

9

10

11

Oxygenated GasolineE0 gasolineE20E30E50FFV Fuel

Gasoline maximumRVP for sampleswith no ethanol (9 psi)

Gasoline maximum RVP for oxygenatedsamples (10 psi)

FFV FuelSpecification Limits5.5 psi to 8.5 psi

Ethanol Blender Pump Quality Survey

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› vehiclesandfuels › pdfs › merit_review_2011 › ... · Quality, Performance, and Emission Impacts of Biofuels and …Samples generally met the requirements of ASTM D7467,