Performance Combustion and Emission of DI Diesel Engine by Thermal Cracked Carbon Filtered Sunflower Acid oil 1 P.Deivajothi, 2 V.Manieniyan, 3 S.Sivaprakasam 1,2,3 Department of Mechanical Engineering, Annamalai University, Annamalai nagar, Tamil Nadu, India Email: 1 pdeivajothi@gmail.com ; 2 manieniyan78@gmail.com; 3 rgssiva2002@yahoo.co.in; [Received:15th Jun.2017; Accepted: 30th Jun.2017] Abstract Gradually the fossil fuel consumption is increasing in all over the world. The global warming is higher due to diesel engine exhaust emission. To reduce the fossil fuel consumption and emission there is a need for alternative fuel. In this present work thermal cracked carbon filtered sunflower acid oil (TCSAO) is used as the alternative fuel in diesel engine. The entire experiment on engine is run in constant speed at 1500 rpm. The performance, combustion and emission are analyzed in various proportions (B20, B40, B60, B80 and B100) of TCSAO biodiesel with diesel at five different loads. The results show that B20TCSAO blend have performance and combustion characteristics closer to diesel. All emission parameters are lower in B20TCSAO compared to diesel and other biodiesel blends. Keywords Acid oil; Biodiesel; combustion; Vegetable oil; I. INTRODUCTION Renewable vitality and biomass sources are turning out to be more alluring because of the expanding lack of ordinary fossil fills, the more discharges of burning produced more emission. With respect to internal combustion engine, biodiesel speaks to a promising contrasting option to petroleum diesel fuel. Biodiesel is a renewable, clean diesel fuel, which is produced using unsaturated fat methyl or ethyl esters. These esters are produced using vegetable oils, creature fats or waste oil utilized as a part of cooking or industry. In developing countries, utilizing biodiesel in diesel engine can assume a vital part in lessening the fossil fuel requirement, the ecological effect, and the unfavorable impacts on human wellbeing [1,2]. Biodiesel is renewable and can be delivered straightforwardly from palatable and nonconsumable vegetable oils, reused waste vegetable oils, and creature fats through the transesterification process. Biodiesel can frame mixes with diesel at different proportion and in this way can possibly in part, or even thoroughly, supplant diesel fuel in internal combustion engine. Biodiesel fuel affects internal combustion engine such as performance and emission [3]. The diesel engine emits many types of emission. The major regulate emission is nitrogen oxide (NOx), carbon monoxide (CO), unburned hydrocarbon (HC) and smoke density and unregulated emissions are carbonyl compounds and light aromatic hydrocarbons. Cost of the biodiesel fuel is an essential factor for use of biodiesel [4]. Since the costs of consumable vegetable oils are high, the utilization of eatable oils in biodiesel preparation expands the costs of biodiesel. The lowvalued feedstocks, for example, utilized waste oils, soapstocks, non-eatable vegetable oils and creature fats, can be seen as an answer for low evaluated biodiesel [5,6,9]. In any case, the utilization of modest oil sources having high free unsaturated fat (FFA) additionally builds the expense of the biodiesel fuel because of additional progressions in the creation [7,8,10]. The biodiesel is produced by various methods such as transesterification process, thermal cracking, catalytic cracking, and micro emulsification. In the present work, the biodiesel is produced by thermal cracking method. The source of raw oil (Sunflower acid oil) is collected from by product of vegetable oil refinery industry. 2.1 Preparation of biodiesel II. EXPERMENTAL The 5 liter of waste refinery oil is filled in the reactor initially, and then reactor is closed with the help of bolt. Here gasket was used to prevent leakage. The temperatures used for this study were 550 º C at a heating rate of 10 º C /min under atmospheric pressure. The condensed liquid product is collected into a bottle. The preparation of biodiesel was in two phases. In the first phase, biodiesel is prepared in thermal cracking. The second phase of the work was to improve the cetane number, calorific value of the thermal cracked biodiesel by carbon filtered method. The thermal cracking setup is shown in figure 1. The reactor was heated to the desired reaction temperature using external electronic resistance. The temperature was measured at two sites with calibrated thermocouples. The product mixture leaving the reactor was condensed in a condenser to separate the gaseous and liquid products. The liquid product was collected in a vessel positioned behind the condenser. Thermal cracked biodiesel was fed into carbon filter. The carbon filter arrangement is as shown in fig 2. Initially cotton was filled some space in glass tube. Then 1
the activated carbon powder was filled in half of the portion of the glass tube and thermal cracked sunflower acid oil was poured in reaming portion. The TCSAO oil was collected at bottom of the glass tube which naturally drained. Improved properties such as lower viscosity, lower specific gravity, increased in calorific value. All contaminates were obtained in the filtered oil. 2.2 Experimental The experimental investigation is conducted in a single cylinder diesel engine with natural aspired. Loading device is used as an eddy current dynamometer, coupled in diesel engine. The entire experiment on engine is run in constant speed at 1500 rpm. Thermal cracked carbon filtered sunflower acid oil (TCSFAO) biodiesel is used as a fuel in various blends such as B20,B40,B60,B80 and B100 compared to diesel fuel. Engin ewas run in five different loads varying from 20% to 100% in equal interval of 20%. Exhaust temperature is measured by K- type thermocouple which was placed in engine tail pipe. Exhaust emissions (HC, CO and NOx) are analyzed in AVL exhaust analyzer and smoke was measured by AVL smoke meter. The combustion parameters (Cylinder pressure and Heat release rate) were measured using AVL combustion analyzer. The experimental arrangement is shown in figure 3. Fig. 1 line diagram of thermal cracking unit Fig. 2 Thermal Cracked Oil Filtration Method III. RESULTS AND DISCUSSION The optimal blend ratio for Thermal Cracked Carbon Filtered sunflower acid oil Biodiesel TCSAO was determined on the basis of performance and emission characteristic. For optimization, experiments were conducted using diesel and the various ester blends. 3.1. Performance Characteristics From fig. 4 it was observed that the variation in Specific fuel consumption (SFC) with load for different blends declined in Specific fuel consumption with increase in load. The SFC in case of all blends was higher compared to diesel in the entire load range. With increase in biodiesel percentage in the blends, the calorific value of fuel decreases. Hence, the specific fuel consumption of biodiesel in blends increases as compared to that of diesel. The variation was due to lower heating value and higher fuel flow rate due to high density of the blends [11,14]. It was observed that the SFC for the blend B20 was close to diesel in full load. The SFC of diesel was found to be 0.252 kg/kwh at full load condition. The SFC at full load with B20TCSAO, B40TCSAO, B60TCSAO, B80TCSAO and B100TCSAO were found to be 0.271 kg/kwh, 0.284 kg/kwh, 0.298 kg/kwh, 0.309 kg/kwh and 0.319 kg/kwh respectively. Figure 5 shows the variation of brake thermal efficiency with brake power for TCSAO blends B20, B40, B60, B80 and B100 in comparison with diesel. Brake thermal efficiencies of B20, B40, B60, B80 and B100 are 29.37%, 28.53%, 27.72%, 27.53 and 27.12% respectively when compared to diesel brake thermal efficiency 31.23% at full load. It is observed that brake thermal efficiency of B20TCSAO is very close to that of diesel among all other blends. This is due to better atomization of B20TCSAO as compared to other blends of biodiesel. Better atomization leads to better vaporization of fuel which enhances combustion process ultimately increasing break thermal efficiency. B100TCSAO brake thermal efficiency is less due to increased viscous nature of biodiesel. 3.2. Emission Characteristics Figure 6 shows the variation of smoke emission with brake power for TCSAO biodiesel blends and diesel. Comparatively diesel smoke emissions with 43 HSU are higher when compared to biodiesel blend B20TCSAO with the values of 40.1 HSU at full load condition. Smoke emissions are higher at high loads as the air fuel ratio decreases with increasing engine loads. For B20TCSAO biodiesel blend, smoke emissions are decreasing due to presence of fairly good amount of oxygen content enhancing complete combustion of fuel compared to diesel. Fig. 3 Line diagram of engine setup 2
Figure 4 Specific fuel consumption against Brake power attributed to increased exhaust gas temperature due to lower heat transfer and the fact that biodiesel has some oxygen content in it which facilitates the NOx formation [12]. The NOx level varies from 190 ppm at 20 % load to 751 ppm at full load and from 162 ppm to 720 ppm with TCGAO blends and diesel respectively. Figure 8 shows the variation in HC emission with brake power. The HC emission from the B20TCSAO blend was lower compared to other TCSAO blends and diesel. The emission of HC mostly depends on the combustion process. Incomplete combustion produces more HC emission or un-burnt hydro carbon fuel emissions. Also the higher cetane number of B20TCSAO blend results in decrease in HC emission due to shorter ignition delay. Also HC emission was found to be increased with increase in the concentration of biodiesel blends. Incomplete combustion produces more HC emission or unburnt fuel emission. In case of high concentration of biodiesel i.e. fuel rich mixtures have insufficient oxygen to react with the carbon. So, complete combustion produces less HC emission. Figure 5 Brake thermal efficiency against Brake power Figure 8 Hydrocarbon against Brake power Figure 6 Smoke density against Brake power Figure 7 Oxides of nitrogen against Brake Power Figure 7 shows the variation in NOx emission with brake power. The result shows that the diesel fuel was having lower NOx emission than TCSAO blends. The NOx emission for diesel and all the blends followed an increasing trend with respect to engine load. The NOx emission in B20TCSAO was observed to be lower compare to other blends of TCSAO. This could be Figure 9 Carbon monoxide against Brake power Figure 9 shows the variation in CO emission with brake power. The CO emission from the B20TCSAO blend was lower compared to other TCSAO blends and diesel. As the load increases blends show higher emission. It was observed that CO initially decreased with increase in engine loads and later it increased with increase in engine loads. CO emission increased significantly with increase in the concentration of biodiesel in the blend. CO was a product of the incomplete combustion due to either inadequate oxygen or insufficient time for the completion of reaction or poor atomization or uneven distributions of small portion of fuel across the combustion chamber. 3
Figure 10 shows the variation of the exhaust gas temperature with brake power. It can be noticed that the exhaust gas temperature increases with increase in the load for all the test fuels. The exhaust gas temperature for diesel, B20TCSAO and B100TCSAO are 301 C, 323 C and 353 C respectively, at full load. It can be observed that the ignition delay is longer for B100, resulting in slow combustion, which reflects in the higher exhaust gas temperatures. It can also be seen that the exhaust gas temperature (EGT) is higher for B100TCSAO compared to diesel. This may be due to the better utilization of oxygen in all TCSAO blends, which promotes the combustion process, and the resulting increased peak temperature leads to increased exhaust gas temperature. Figure 11 Heat release rate against Crank angle Figure 10 Exhaust gas temperature against Brake power 3.3 Combustion Characteristics The variation of heat release rate with crank angle for TCSAO blends in comparison with diesel is shown in figure 11. By analysis of figure, it is observed that heat release rate at full load for diesel, B20TCSAO, B40TCSAO, B60TCSAO, B80TCSAO and B100TCSAO are 131.68 kj/m 3 deg, 125.07 kj/m 3 deg, 122.03 kj/m 3 deg, 118.39 kj/ m 3 deg, 110.90 kj/m 3 deg and 108.37 kj/m 3 deg respectively. The highest heat release rate is observed in diesel and followed B20TCSAO compared to all other blends. This is due to more fuel accumulation in the ignition delay period, which releases the maximum heat as it is having calorific value close to diesel value [13,14]. The B20TCSAO blends having shorter delay period compared to other blends. B100TCSAO gives the least heat release rate due to its lower calorific value. Figure 12 shows the variation of cylinder pressure with brake power for TCSAO blends in comparison with diesel. Peak cylinder pressure at full load obtained for diesel is 68.12 bar where as peak cylinder pressures for B20TCSAO, B40TCSAO, B60TCSAO, B80TCSAO and B100TCSAO are 65.44 bar, 65.40 bar, 65.26 bar, 65.17 bar and 64.60 bar respectively. The peak cylinder pressure for B20TCSAO blend is higher to that of other blends at the same operating conditions. The reason for higher peak pressure of the B20TCSAO is high calorific value and proper burning rate when compared to other blends. Lower calorific value of B100TCSAO blend is the reason for its lowest peak cylinder pressure. Figure 12 Cylinder pressure against Crank angle IV. CONCLUSIONS The following conclusions were drawn based on engine performance, combustion and emission: 4 With increase in biodiesel percentage in the blends, the calorific value of fuel biodiesel decreases. Hence, the specific fuel consumption of biodiesel in blends increases as compared to that of diesel. It was observed that the SFC for the blend B20TCSAO was close to diesel in full load. Brake thermal efficiency of B20TCSAO is very close to that of diesel among all other blends. This is due to better atomization of B20TCSAO as compared to other blends of biodiesel. B20TCSAO biodiesel blend smoke emissions are decreasing due to presence of fairly good amount of oxygen content enhancing complete combustion of fuel compared to diesel. The higher cetane number of B20TCSAO blend results in decrease in HC emission due to shorter ignition delay. The NOx emission in B20TCSAO was observed to be lower compare to other blends of TCSAO. This could be attributed to increase exhaust gas temperature due to lower heat transfer and the fact that biodiesel has some oxygen content in it which facilitates the NOx formation. The highest heat release rate is observed in diesel and followed B20TCSAO compared to all other blends. The peak cylinder pressure for B20TCSAO blend is higher to that of other
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