International Journal of Pure and Applied Mathematics ...batch/semi batch [6], fixed bed, fluidized bed, spouted bed, microwave [7] and screw kiln. Batch or semi -batch reactors have

Production of Diesel like Fuel from Municipal Solid Waste Plastics for using in CI Engine

to study the Combustion, Performance and Emission characteristics

B Sachuthananthan, D Raghurami Reddy,C Mahesh, B Dineshwar

Department of Mechanical Engineering, Sree Vidyanikethan Engineering, Tirupati, Andra

Pradesh-517 102, India

Corresponding Author: [email protected], Contact Number: +91 90433 33326

Abstract

In this work an attempt has been made to produce diesel like fuel from waste plastics obtained

from municipal solid waste through the process of pyrolysis to meet the strategies of effective

waste management and waste to wealth. Plastics from Tirupati municipality was collected and

treated to remove dirt and moisture. Later it is was crushed to smaller size to be accommodated

in the reactor of volume 0.08m3. Later heating was done gradually to reach 400 deg C so that all

the shredded plastic got melted to produce a gas which can be condensed to produce diesel like

fuel. Natural Zeolite was used as catalyst to speed up the reaction and also to reduce the

reaction cycle time consumption and also to reduce the input energy consumption.The

experimental analysis reveals that out of 5 kg of plastic used for melting in a reactor, the product

yield was 75%. Upon usage in diesel engines it was observed the raw fuel can be a pure

substitute to conventional diesel.It was also observed that the performance and emission

characteristics was found to increase slightly with the increase in load. The combustion

efficiency was also found to increase with the increase in other factors.

Keywords:Production of plastic oil from municipal waste-DI diesel engine-combustion-

performance and emission study.

1.Introduction

The growth of the plastic consumption has been occurring rapidly in the last six decades due to

their ability to be simply formed, its light weight and non-corrosive behavior, it is relatively

cheap, easily available and theversatility replace to conventional materials.These excellent

properties have been used to replace the use of wood and metals. The world’s annual plastic

consumption has increased about 20 times from 5 million tons in 1950s to nearly 100 million

tons [1].

However, the great number of consumptions would increase the product of plastics wastes

which led to the environmental problems. Land filling is not a suitable option for disposing

plastic wastes because of their slow degradation rates. The use of incinerator generates some

pollutants to the air, which also cause environmental issues. Environmental hazards due to

mismanagement of plastics waste are given below

1. Plastics are no biodegradable material. It takes 300-500 year tobiodegrade.

2. Garbage containing plastics, when burnt may cause air pollution by emitting toxicgases.

International Journal of Pure and Applied MathematicsVolume 119 No. 12 2018, 85-98ISSN: 1314-3395 (on-line version)url: http://www.ijpam.euSpecial Issue ijpam.eu

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3. Garbage mix with plastics gives problem in landfill operation.

4. Lack of recycling plant increases the possibility of littering of plastic in the environment.

5. Burning of plastics give NOX, COX, SOX, particulate, dioxins, furans and fumes that

increase air pollution with results in acid rain and increase global warming.

Therefore, recovering and recycling methods have been used to minimize the environmental

impacts and to reduce the damage of plastic wastes.

Chemical recycling via pyrolysis process is one of the promising methods to recycle waste

plastics which involvethermo chemical decomposition of organic and synthetic materials at

elevated temperatures in the absence of oxygen to produce fuels. The process is usually

conducted at temperatures between 500-800oC [3].

The low thermal conductivity and high viscosity of plastics are the major challenges for

designing the cracking reactor. Several reactor systems have been developed and used such as

batch/semi batch [6], fixed bed, fluidized bed, spouted bed, microwave [7] and screw kiln. Batch

or semi-batch reactors have been used by many researchers because of its simple design and easy

operation.

1.2 Target of waste plastics into liquid fuel(Recycling Technologies)

1. Mechanical Recycling of waste plastics into reusable product is difficult an

unfeasible due to contamination of plastics, difficulty to identifying and separating different type

of plastics.

2. Uncontrolled incineration of plastics at higher temp above 850 deg Celsius produces

polychlorinated dibenzo-p-dioxins, a carcinogen (cancer causing chemicals). Open-air burning of

plastic occurs at lower temperatures, and normally releases toxic fumes and many oxide gases.

So flue gases treatment use for protect environment and health problems in incineration plant.3.

Chemical recycling could lead to useful raw materials via by degradation an

monomerization of plastics waste, but no method of this primary recycling currentlyavailable.

The degradation of some plastics into chemicals has been reported in

research level.

Gasification and blast furnace of plastics waste to produce gases that are carbon

dioxide, nitrogen, carbon mono oxide, hydrogen and methane at higher temp above 800 deg

Celsius.[2]

International Journal of Pure and Applied Mathematics Special Issue

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1.3 Energy Demand

Fossil fuel i.e. coal, petroleum and natural gas age is expected to span only 1000 year

of human civilization. It is the limited sources which are likely to be

exhausted in few more decades or centuries. Increasing population and fuel consumptionrates

increase in petroleum prices and due to this the energy starvation is felt by ever

developing and less developed country.

The Growing energy demand is given in table 1.Some developing countries like India have to

import petroleum for transportationand chemical industry sector. The prices of petroleum are

increasing due to increase in prices in the international market. Conversion of waste plastic will

satisfy some part of objectives in National Energy Strategy which are given below:

1. To reduce petroleum Imports

2. To reduce the annual growth of total energy demand to 2 percent from 4 to 6% byconservation

of energy.

3.To develop alternative sources of energy.

Table 1: Growing Energy Demand.

World Primary Energy Demand

Year (hexajoules/year)

1972 270

1985 390

2000 590

2020 840

(S. Rao and Dr B.B. Parulekar, 2012).[4]

2.Experimental Apparatus and procedure

2.1 Pyrolysis

Pyrolysis is the chemical decomposition of organic substances by heating.This process, involves

Pyrolysis technology where thermal degradation process takes place in the absence of oxygen.

In this experiment Plastic waste is treated in a cylindrical reactor at temperature of 350ºC –

400ºC. The plastic waste was cracked by adding catalyst and the gases are condensed in a series


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of condensers to give a low sulphur content distillate. The non-condensable gas goes through

water before it is used for burning. Since the waste plastics is processed about 350ºC – 400ºC

and there is no oxygenin the processing reactor, most of the toxics are burnt. It breaks large

hydrocarbon chain into smaller ones. Pyrolysis requires higher temperature and high reaction

time. The process of oil from waste plastics is as shown in Figure 1.

It prevent formation of COX, NOX, SOX due to the absence of oxygen.Also the

resulting fluid have low octane value, higher pour point of diesel and high residue content pour

point of diesel. Catalyst use for this purpose is solid acids such as silica, alumina

zeoliteβ, zeoliteY, mordenite, HZSM-5, MCM-41. Acidic catalysts (HZSM-5,Zeoliteymordenite

and so on) have greater efficiency than less acidic ones, for example amorphous alumina silicate.

The pore size and structure of catalyst determine their performance of cracking reaction as well

as production, for example mordenite size (about 7x8Ȧ) larger givelarge product molecules

while HZSM-5 have smaller pores size(5x5Ȧ) give small molecules[6].(P.A. Parikh and Y.C.

Rotliwala, 2008)

S.no Properties WPO Diesel

1 Density @ 30 °C in

(g/cc)

0.7930 0.84 to 0.88

2 Ash content (%) < 0.01%

(wt)

0.045

3 Calorific value (kJ/kg) 41,858 42,000

4 Kinematic viscosity, cSt

@ 40°C

2.149 5

5 Cetane number 51 55

6 Carbon residue (%) 0.01 % (wt) 0.20

7 Sulphur content (%) <0.002 <0.035

8

9 Flash point (°C) 40 50

10 Fire point (°C) 45 56

11 Pour Point,°C -43 -15

12 Acidity (mg KOH/gm) 0.16 0.20

Table 2:Comparison of properties of waste plastic oil and Diesel

The fuel which has been prepared using waste plastic through the process of pyrolysis, which is

shown in the photographic view below,can be used in a DI diesel engine to study the

combustion, performance and emission characteristics.


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Fig. 1 Photographic view of the experimental setup

Fig. 2 Photographic view of the waste plastic oil

The Experimental procedure involves observing and taking safety precautions, observations and

measurement of engine performance, emissions and combustion parameters using appropriate

instruments. It includes intake air measurement, fuel measurement, power measurement, cylinder


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pressure measurement and emission measurements. The schematic diagram of the experimental

set up is shown in Fig. 3.Fuel-metering systems were provided to maintain the rated speed and

the corresponding fuel consumption was calculated.The electrical dynamometer was used for

measuring power output of the engine.

The electrical power generated by the dynamometer is usually dissipated as heat through banks

of electrical resistances. The load and speed can be increased or decreased on the dynamometer

and thereby on the engine, by switching on or off the load resistances and by varying the field

strength. The output of the generator must be measured by electrical instrument and corrected in

magnitude for generator efficiency. Exhaust emission from the engine was measured with the

help of AVL DI Gas 444 analyzer and smoke intensity was measured with the help of Bosch

AVL 437 smoke meter. Bosch smoke meter usually consists of a piston type – sampling pump

and a smoke level measuring unit. Two separate sampling probes were used to receive sample

exhaust gases from the engine for measuring emission and smoke intensity, respectively. A

50mm diameter filter paper was used to collect smoke samples from the engine. A K-type

thermocouple and a temperature indicator were used to measure the exhaust gas temperature.

The cylinder pressure was measured using a Kastler (601A) water cooled pressure transducer. A

Kastler crank angle encoder on the crankshaft (7200 points per cycle) was used to clock pressure

data acquisition. For each measured point, the pressure data of 100 cycles we rerecorded. The

analysis software AVL idiom to determine the Heat release rate, cumulative heat release rate,

etc. was used.

Initially the test engine was started at no load for the engine to warm up.

2.1.1 Experimental Setup

Figure.3 Schematic layout of experimental setup

1. PC2.ECU3.Surge tank 4.Heat exchanger 5.Gas analyser6. Exhaust control valve 7. Crank

angle encoder8.Temperature sensor9.EGR valve10.Back pressure valve11.Fuel pump12.Fuel

tank vapourizer13.Pressure sensor


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3. Estimation of uncertainty

Ambiguities and uncertainties are to be estimated while conducting an experimental analysis.

These inaccuracies may arise due to environmental factors, errors in calibration of instruments,

human errors while observation and reading. In order to get more accurate uncertainty limits for

computed parameters the principle of root sum square method was used and it is given by

equation -1.

R= ∑ Xi 2

-- (1)

where R is the total percentage of uncertainty and Xi is the individual uncertainty of computed

parameters. The total percentage uncertainty of computed parameters were calculated and given

below

R1= X12+X2

2+X3

2+X4

2+X5

2

R= (1)2+(0.4)

2+(1)

2+(0.1)

2+(0.2)

2

R= ± 1.48%

4. RESULTS AND DISCUSSION

4.1 General

The results obtained from the present work in terms of performance, combustion and emission

characteristics of the engine observed are detailed. All the results are presented with a

comparison between the characteristics of conventional diesel, biodiesel, and also with different

fuels blends of gasoline with diesel and biodiesel.

4.2 PERFORMANCE CHARACTERISTICS

4.2.1. Cylinder Pressure

The combustion characteristics were analyzed based on the measured in-cylinder pressure.

Figure.3 shows the variations of cylinder pressures with different loads at different fuel

combinations. From the figures, it can be seen that the occurrence of peak pressure advances

with respect to the top dead centre with an increase in load. Also, the occurrence of peak

pressure retards with an increase in blends. This leads to an increased rate of pressure rise and

engine noise, whereas the cylinder pressure reduces for diesel and the occurrence of peak

pressure is maximum in blends. The ignition delay has been increased in increasing the diesel

concentration and the engine knock increases at higher load with these blends. In general, peak

pressure varies from about 40 to 75 bars for the entire load range considered.


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Figure 4. Crank angle Vs. Cylinder pressure

4.2.2. Brake Thermal Efficiency

The effect of brake thermal efficiency over various loads is shown in Figure 5. There is a steady

rise in brake thermal efficiency as the load increases in all the cases. As the brake thermal

efficiency is a function of chemical energy and the brake power developed from it, BG10 fuelled

operation resulted in higher brake thermal efficiency compared to diesel and other fuel blends.

Figure 5. B.T.E Vs Load

4.3 EMISSION CHARACTERISTICS

4.3.1. HC Emission

The variation of unburned hydrocarbons over various loads is shown in Figure 6. Improper

combustion of fuel, improper fuel injection timing and low combustion chamber temperature are

the few reason for the formation of HC emissions. It is found from the graphs that the Hydro

carbon emissions increase for all loads and for all fuels. At 75% load HC emissions decreases for

all fuel blends except diesel.


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Figure 6. HC Vs Load

4.3.2 Oxides of Nitrogen

Figure 8. shows that High temperature and availability of excess oxygen inside the engine

cylinder contributes to the formation of NOx emission. The NOx formed in the engine cylinder is

basically the combination of NO and NO2. It can be seen from the graphs that the oxides of

nitrogen increase with increase in load for all the fuel blends. For B100 NOx emission is found

to be high compared to other fuels and diesel has low NOx emission.

Figure 8.NOx Vs Load

4.3.4. Carbon Monoxide

Insufficient quantity of oxygen and less cycle time are the two main reason for the formation of

CO emission. In this experimental work the CO emission is found to be higher for diesel and

30% biodiesel gasoline blends only at higher loads. This may be due to the reason that as the

oxygen content in the fuel increases the CO formation decreases due to the oxidation of CO to

CO2it is represented in Figure.9


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Figure 9. CO Vs Load

5. CONCLUSION

To minimize the diesel fuel usage, fuel properties of WPE and their blends with diesel fuel (D)

such as density, Cetane number, pour point, flash point, and viscosity were determined.

Then,fuel properties, engine performance, and exhaust emissions of the products were

determined and they were compared with the petroleum products.

It is seen that fuel properties of blends are found comparable with those of diesel fuel within the

EN 590 Diesel Fuel Standard and they can also be used as fuel in compression ignition engines

without any modification.

Fuel properties of waste polyethylene blends are comparable with those of diesel fuel except the

Cetane number and pour point values of WPE100 and CPE100.

Power output of engine with blends increased maximum by 1.63% with WPE5 blend compared

with diesel fuel. Torque output of blends decreased by 2.73% with WPE5 compared to diesel

fuel especially at higher engine speeds.

While CO emission is decreased by 20.63% with WPE5 blend and CO2 emission is increased by

3.34% with WPE5 blend. NOxemission is increased by 9.17% with WPE5 compared to

dieselfuel.

Finally, WPE5 blend can be the best alternative fuel blend for diesel engines not only for its

performance characteristics but also for the environmental aspects.

ACKNOWLEDGEMENT

I would first like to thank our chairman Dr M.Mohan babu for his continuous support to the

progress of the work. The doors of our chairman office was always open whenever I ran into a

trouble spot or had a question about my research or writing. He consistently allowed this paper to

be my own work, but steered me in the right the direction whenever he thought I needed it.


94

I would also like to thank our Head of the Department who constantly encouraged us in

consistently doing this work. I would also like to acknowledge faculty members of our

mechanical engineering department to helped us in accomplishing this research work.

Finally, I must express my very profound gratitude to my parents and to my partner, spouse, and

mychildren’s who spared their time without me and for providing me with unfailing support and

continuous encouragement throughout my research work. This accomplishment would not have

been possible without them.

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[4] S Rao, Dr. B.B Parulekar Energy Technology (Non Conventional Renewable &

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[5]Antony Raja and Advaith Murali, 2011 Conversion of Plastic Wastes into Fuel, Journal of

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Documents

International Journal of Pure and Applied Mathematics ...batch/semi batch [6], fixed bed, fluidized bed, spouted bed, microwave [7] and screw kiln. Batch or semi -batch reactors have