Performance and Emission Studies of a SI Engine using Distilled Plastic Pyrolysis Oil-Petrol Blends

. In the present work, an experimental investigation is carried out to evaluate the use of plastic oil derived from waste plastic which used in a Spark Ignition engine. Experiments are conducted, the measured performance and emissions of plastic oil blends at different proportions are compared with the baseline operation of the SI engine running with gasoline fuel. Engine performance and exhaust gas emissions such as carbon monoxide, total unburned hydrocarbons, carbon dioxide and oxides of nitrogen are measured. From the experiments it is observed that 50% Distilled Plastic Pyrolysis Oil (50%DPPO) exhibits the substantial enhancement in brake power, brake thermal efficiency and reduction in brake specific fuel consumption running at full load conditions among different blends and pure petrol. There is also noticed decrement of carbon dioxide and unburned hydrocarbons emissions at the same blend. The experimental result shows that plastic oil shall conveniently be used as a substitute to gasoline in the existing SI engines without any modifications.


Introduction
Increasing industrialization, urbanization and changes in the pattern of human life, will acco mpany the process of economic growth but at parallel causes for increasing quantities of environ mental wastes leading to increased threats to it. Developing countries like India depend s heavily on o il import. Fro m the last two decades research around the world is concentrating on alternative energy generation techniques, it is the high time to generate the energy by alternative sources. Alternative fuels for both spark ignit ion and compression ignit ion engines have become very imperative o wing to increased environmental p rotection concern, need to reduce dependency on petroleum products and even socioeconomic aspects. The past three and half decades are witnessed for an exp losive growth of the p lastic utilizat ion across world. The production of synthetic polymers represented by polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC). These plastics are widely used in many important day to day applications such as clothing, household appliances and in automotive products and aerospace. While we enjoying the conveniences that plastics can provide, the treatment of waste plastic becomes an unavoidable and imminent issue.
In this context, it is urgent need to search a safety and effective ways to recycle waste plastics. Recently new ways of environmental friendly waste plastic recycling have been of interest, and among them, the use of waste plastics as a supplementary fuel has attracted interest of many researchers. Mehdi et al. [1] reviewed the PVC wastes and suggested chemical recycling is the best process for the environmental pollution problems and addressed several recent separation and recycling problems. Mitsuhara et al. [2] attention is also focused on using oil derived fro m waste plastics in d iesel engines. Williams et al. [3] investigated the diesel engines are the most preferred power p lants due to their excellent driveability and higher thermal efficiency. Naima et al. [4] had investigated alternative fuels for internal co mbustion engines by using waste plastics, waste engine oil and waste cooking oil. The propert ies of the oil derived fro m these three types of oils were analysed and compared with the diesel fuel. Moinuddin Sarker, et al. [5] used stainless steel reactor to produced hydrocarbon vapors fro m waste thermoplastics. Plastics are nonbiodegradable polymers mostly containing carbon, hydrogen and few other elements which were the root cause for the plastic waste management and environmental issues [6][7][8]. Many researchers are investigated the usage of waste plastic oil and waste tyre oil as an alternative fuel for d iesel engine. Shan muga Vadivel et al. [9] are investigated the performance and emission characteristics of Nano engine running on plastic oil with gasoline blends. Their results shows an increase in brake thermal efficiency for the blends when compared to that of gasoline fuel. [10][11][12] were run the diesel engine blended with plastic oil to evaluate the performance and emission characteristics without any engine modificat ions, their investigation clears that the plastic oil is alternate fuel for d iesel engine. [13][14][15][16][17] are experimentally investigated on a diesel engine using waste plastic oil and tyre o il blends with exhaust gas recircu lation. Their results shows that plastic and tyre oil blended engines suffers with high NO x emission, which can deduced by using exhaust gas recircu lation. Vijaya Ku mar et al. [18] had investigated the performance and emission characteristics of diesel engine with three hole injector by using tyre oil blends and their results shows that 20% tyre oil blend was given better performance compared with diesel and other blends at all injections pressures. [19][20][21][22] are conducted experiments on diesel engine fuelled with tyre pyrolysis oil blended at different proportions to evaluate the performance and emissions with and without ethanol. [23,24] are investigated the performance, emission and combustion studies using distilled tyre pyrolysis oil blends on diesel engine without any engine modificat ion. Ho wever, very little work has been done to test their use in high-speed diesel engines.
The main objective of this research is derived fro m the literature rev iew, analyze the engine performance, combustion and emission characteristics of petrol engine fuelled with distilled waste plastic o il blends with petrol fuel. The crud waste plastic oil prepared fro m the pyrolysis process was carried out the batch distillat ion apparatus. This distilled plastic oil b lended with gasoline at different volu me fractions and the performance and emission characteristics was carried out on 4stroke single cylinder kerlosker petrol engine without any engine modifications.

Preparation of Plastic Pyrolysis Fuel
The production method for the conversion of plastics to liquid fuel is based on the pyrolysis of the plastics and the condensation of the resulting hydrocarbons are shown in Fig. 1. Pyro lysis refers to the thermos -chemical process for conversion of waste plastic by heating the feed stock at high temperature in absence of air which produces gaseous products which is them condensed to give liquid fuels consisting of pyrolytic oil or liquid oil.

Figure 1. Pyrolysis process of waste plastics
Waste plastic is t reated before feed in to the reactor. The feed stock passed to hopper through mills and send in to reactor by the hot screw conveyor. In reactor waste plastic is subjected to high temperature and low pressure by the hot gasses coming fro m co mbustion chamber where they will deco mpose at 450°C to 550°C. Vapors, gasses and char products are generated and they passed through cyclone filter. The char is collected at the ash tank and gasses are send to condenser. In the condenser heat fro m this gasses is utilized to generate steam. The steam can used to generate the power as by product. So, that the plastic vapors are gets condensed in the condenser. The condensate oil is separated and used to further transformation, the non-condensable gasses are feed back to the reactor as flu idized gasses. Almost 70-80% of gaseous products are converted in to liquid fuels providing a good quantity of liquid fuel which then can be enhanced.

Reducing Viscosity of Plastic Pyrolysis Oil
The plastic oil which obtained by the pyrolysis method has some disadvantages such as high viscosity, low volatility, gumming effect and carbon residue. So, that the demerits impose a negative impact on the engine performance, emissions durability. Therefore, before using they as fuels the viscosity of the plastic oil have to be reduced. One interesting method to reduce the viscosity of the plastic oil and also to improve the spray formation so as to use them in the spark ignit ion engines are distillation. Th is process applied for petrol and diesel grade fuel production process. Fig. 2, distillat ion apparatus is used for to remove the impurit ies fro m basic fuel and increase the volatility of fuel. After distillat ion volatility of fuel is increase, it helps to homogenization of air fuel mixtu re in case of SI engine carburetor itself and also avoid logging of fuel impurit ies in filter or in nozzle holes.

Figure 2. Batch distillation apparatus
Waste plastic to fuel was use for further distillat ion process and making petrol grade fuel. Distillation colu mn was use for distillation process. Distillation process set up different columns with different temperature profile like low boiling point fuel to high boiling point fuel. Petrol grade fuel co llected fro m fract ional co lu mn and temperature range was 90°C to 160°C. This fuel hydrocarbon compound also heavier and this fuel are not igniting. Co llected petrol grade fuel percentage was about 42% and rest of all other fractional fuel percentage was 58% including diesel grade fuel and light gas also. Fractional d istillation process was also generating some light gases. Plastic pyrolysis fuel to different fuel by using fractional distillat ion colu mn used for heat applied with different colu mn temperature wise and fuel break down into shorter into longer chain wise and co me out 03002-p.2

ICMM 2016
into different fraction co lu mn then collected into separate container.
In the present study distillate of the plastic oil is obtained in the same boiling range of petrol (90-160 o c). The oil is obtained by pyrolysis come distillation is shown in the below Fig. 3.  As the derived plastic fuel fro m the waste plastic after pyrolysis and distillation catches fire in roo m temperature itself, so flash and fire point is not valid for the arrived fuel as same like as petrol. And the extraction fro m the distillat ion i.e. plastic fuel slightly having more calorific value compare to that of gasoline, and also having density more than that of the gasoline. So me o f the properties of the petrol, plastic pyrolysis oil (PPO) and distilled plastic pyrolysis oil (DPPO) are compared in table 1. The tendency of a fuel to vaporize is also characterized by determin ing a series of temperatures at which various percentages of the fuel have evaporated (boiling temperatures), as described in A STM D86, Test Method for Distillation of Petro leu m Products. The temperatures at which 10 percent, 50 percent, and 90 percent evaporation occurs are often used to characterize the volatility of gasoline.The d istillation characteristics curves of the petrol and plastic fuel as well as the different blends are shown in Fig. 4. Fro m Fig. 4, it can be observed that the volatility property is more in the plastic pyrolysis distilled oil b lends compared to the 100% petrol.

Preparation of Plastic Oil Blend
The basic properties of DPPO-PF were measured and compared with conventional petroleum fuels. The Carbon content are higher for DPPO than petrol fuel. In the present work 10%DPPO, 20%DPPO, 30%DPPO, 40%DPPO and 50%DPPO of DPPO was blended with petrol fuel on volu me basis and observed for 15 days to check for any separation. No such separation was noticed. DPPO blended with PF is indicated as 10%DPPO. For example, 10%DPPO blended with 90% PF is denoted as 10%DPPO.

Experimental Setup
The Test rig co mprises of the following apparatus and the layout is shown in Fig. 5, Petrol engine Electrical Dynamometer Burette setting with fuel consumption pipe and fuel tank Air and fuel supplied to engine Gas analyzer and Display The test rig consists of single cylinder, 4-stroke, aircooled petrol engine coupled to a electrical dyna mo meter, which acts as a loading device. A six channel temperature indicator provided to measure the temperature at various points of the test rig.  arrangement consisting of a digital ammeter and voltmeter and single phase main switch. All this above instruments with panel board are mounted on the M.S. Fabricated stand. The speed of the engine is measured by the use of non-contact type digital tachometer.

AVL Gas Analyzer
The purpose of the AVL gas 444 is to measure the relative volu mes of certain gases constituents in the exhaust gas of motor vehicles has shown in Fig. 6. These gases are carbon mono xide, carbon dio xide, hydrocarbons, and oxygen nitric o xide. The air fuel ratio is calculated fro m the CO, CO 2 , HC and O 2 , constituents and displayed. The Liquid crystal display shows the constituents of the gas once the gas is allowed to flow in. It is a standard output device for the A VL gas 444. The functional keys serves for various purposes such as to fine filter helps in removal or separation of water which enters into meter with tested gas. This prevents the damage of the mach ine. Frequently the filter has to be replaced depends on the manufacturer catalogue. The water inlet allo ws the gas from the engine exhaust into the machine. The exhaust gas probe takes a sample of gas fro m the exhaust tail pipe of the vehicle and carries it to the gas analyzer via exhaust gas hose. The important elements that are present on the back side are condensate outlet, ventilator and fan, sensors rpm and oil temperature RS 232 connection and power supply.

Brak e Specific Fuel Consumption
Brake specific fuel consumption of an engine is defined as the rate of fuel consumption per unit power produces. This is an important performance parameter as it determines the mileage of the vehicle. It can be seen fro m the Fig. 7, that the BSFC of the engine decreased with increase in load and also BSFC decreased with increase in the proportion of plastic o il in the blend. Density and calorific values of the blend increases with increases in the plastic proportion as the plastic oil is denser than petrol and also have higher calorific value. Efficiency   Fig. 8, shows the variation of brake thermal efficiency with load for various blends. Brake thermal efficiency increased with increase in load with the rate of variat ion decreasing with increase in load acting. For the 1/6 th , 1/ 3 rd and 1/2 load conditions the brake thermal efficiency of 50%DPPO is more than the pure Petrol, after half load condition the brake thermal efficiency is fall and again raised at the full load conditions.

Carbon Monoxide
Fro m Fig. 9, it can be observed that, CO emissions increased with increase in load reached the maximu m at 4 th or 5 th load and there after slightly decreased. CO emissions are due to incomplete co mp lete combustion of fuel either due to inadequate oxygen or flame quenching. In the present study as the engine is equipped with a carburetor to supply fuel to the engine cylinder, fuel air mixtu re might not be ho mogenous throughout the cylinder. CO emissions increased marginally with increase in the proportion of the plastic oil in bend.

Oxides of Nitrogen
NO x emissions increases with increase in the peak cylinder temperature. Peak cylinder temperature increases with increase in load. NO x emissions also varies with air fuel ratio, but in petrol engine air fuel ratio does not vary much with load. Fro m Fig. 10, it can be observed that 03002-p.4 NO x emissions increased with increase in load as predicted.  In the present study as the plastic oil has more calorific value than petrol, engine temperatures might be higher when the engine is operated with plastic oil. The HC and CO emissions exhib ited an opposite trend with increase in plastic o il content in b lend. Th is might be due to in-cylinder temperatures being near or below the H 2 O 2 breakdown temperature, where rad icals released fro m rapid H 2 O 2 breakdown cause HC molecu les to break down to form CO . When the temperatures are near or below 1000 K, partial o xidation of HCs into CO does not occur thereby causing higher emissions of HCs and lo wer emissions of CO.

Conclusions
Plastic pyrolysis distilled fuel is tested on the SI engine and the performance and emissions characteristics are compared with the different blends and the following observations are made.
Plastic oil obtained fro m the pyrolysis of a plastic waste can be used as a fuel in petrol engine by obtaining the distillate in the temperature range of petrol. Petrol and plastic pyrolysis distilled fuel can be readily blended without any precautions or the methods as both their viscosity and density are of in the same range. It is observed that the distillation characteristics of both petrol and plastic pyrolysis distilled fuel are more or less similar. The basic specific fuel consumption of the engine fuelled with 50%DPPO is 26.84 % lesser than that of the engine fuelled with sole petrol at full load. The brake thermal efficiency of the engine with 50%DPPO is 19% higher than that of the sole petrol operation. The CO emissions in 50%DPPO are 1.7 t imes more than that of the engine fuelled with the 100% Petrol. The unburnt hydrocarbons are 43.58% lesser in the 50%DPPO engine operation co mpared to the sole petrol operation. The NO x emissions are 1.6 times more in the 50%DPPO compared to that of the engine with 100% petrol as fuel. In the view of performance, experiments can run beyond 50% distilled p lastic pyrolysis oil without any engine modification, but while considering in NO x emissions, they are proportionately increasing with the percentage of distilled plastic pyrolysis oil co mpared to 100% petrol. Which should be consider as per EPA regulation.