INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING AND

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1 INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING AND International Journal of Mechanical Engineering and Technology (IJMET), ISSN (Print), ISSN (Online) TECHNOLOGY Volume 3, Issue (IJMET) 2, May-August (212), IAEME ISSN (Print) ISSN (Online) Volume 3, Issue 2, May-August (212), pp IAEME: Journal Impact Factor (212): (Calculated by GISI) IJMET I A E M E INFLUENCE OF CNSL BIODIESEL WITH ETHANOL ADDITIVE ON DIESEL ENGINE PERFORMANCE AND EXHAUST EMISSION T. PUSHPARAJ 1, S. RAMABALAN 2 1 Assistant Professor, Department of Mechanical Engineering, Kings College of Engineering, Thanjavur, Tamil Nadu, India, tpushparaj26@gmail.com Mobile number: Professor, Department of Mechanical Engineering, EGS Pillay Engineering College, Nagapattinam, Tamil Nadu, India, cadsrb@gmail.com Mobile number: ABSTRACT Vegetable oils are a potential alternative to the partial or total substitution of diesel fuels. In this study, we used ethanol as an additive to investigate the possible use of higher percentages of biodiesel in an unmodified diesel engine. Biodiesel was made by pyrolysis process. Cashew nut shell liquid (CNSL) was selected for biodiesel production. Number 2 diesel fuel containing 2% biodiesel and 8% diesel fuel, is called here as. The effects of ethanol, blended with in 5, 1, 15 % by volume were used in a single cylinder, four strokes direct injection diesel engine. The effect of test fuels on engine torque, power, brake specific fuel consumption, brake thermal efficiency, exhaust gas temperature, were ascertained by performance tests. The influence of blends on CO, CO 2, HC, NO and smoke opacity were investigated by emission tests. The experimental results showed that the exhaust emissions for 1% ethanol with were fairly reduced, especially the NO is reduced remarkably by 57% while comparing. Keywords: Biodiesel, Cashew Nut Shell Liquid (CNSL), Emission, Ethanol, Pyrolysis 1. INTRODUCTION engines are widely used for their low fuel consumption and better thermal efficiency. Also, rapid depletion of petroleum fuels and their ever increasing costs have led to an intensive search for alternative fuels. Different vegetable oils such as soybean oil, castor oil, rapeseed oil, Jatropha curcas oil have been considered as alternative fuels for diesel engines [1]. Vegetable oils are not suitable direct replacements for diesel fuel in engines, boilers or 665

2 cogeneration systems, due to their inappropriate physical properties such as longer molecule chains, lower pour points, lower vapor pressures, higher viscosities and higher flash points. These features cause poor atomization, poor vapor air mixing, low pressure, and incomplete combustion and engine deposits. However, it is possible to reduce the viscosity of vegetable oil, improve the physical features of vegetable oil through dilution, pyrolysis, micro emulsion and esterification. Esterification is a kind of catalytic reaction in which oil or fat is reacted with alcohol to form esters (biodiesel). Yongsheng Guo et al. [2] list the merits of biodiesel like biodegradable, nontoxic, low emission profiles compare to diesel. Essentially, no engine modifications are required to substitute biodiesel for diesel fuel that can maintain the engine performance. Vegetable oils and ethanol are derived from agricultural products and are renewable and biologically less objectionable in the environment [3]. The world production figures of cashew crop, published by FAO, were around 2.7 million tons per annum. The major raw cashew producing countries with their production figures in 25 (as per the UN's Food and Agriculture Organization) are Vietnam (96,8 tons), Nigeria (594,), India (46, tons), Brazil (147,629 tons) and Indonesia (122, tons). India ranks first in area utilized for cashew production, though its yields are relatively low. Collectively, Vietnam, India and Brazil account for more than 9% of all cashew kernel exports. India is the largest producer and exporter of cashews, Anacardium occidentale Linn.,in the world. In India, Cashew cultivation now covers a total area of.7 million hectares of land, producing over.4 million metric tons of raw cashew nuts. The cashew nut shell is about 3mm thick, having a soft feathery outer skin and a thin hard inner skin. Between these skins is the honeycomb structure containing the phenolic material known as CNSL. Inside the shell is the kernel wrapped in a thin skin known as the testa. Mallikappa et al. [4] find the constituents of cashew nut. The nut consists of the following, kernel, kernel liquid, testa, rest being the shell. The raw material for the manufacture of CNSL is the Cashew nut shells Pyrolysis is one of the thermo chemical conversions in absence or limited supply of air or oxygen [5]. In the cashew nut shell, cashew nut shell liquid occurs mainly as anacardic acid (~9%) and cardol around slightly lower than 1%. Risfaheri et al. [6] narrate the pyrolysis procedure of CNSL, the pyrolysis is done in a reactor at a vacuum pressure of 5kPa and at various maximum temperatures between 4-6 o C, with an increment of 5 o C for each experiment. The volatiles removed on pyrolysis are gradually condensed in a pre-weighed condensing train, from atmospheric condensation to condensation in an ice bath (5-7 C) [7]. The decarboxylated cardanol is termed as CNSL biodiesel. The biodiesel obtained from CNSL not required for further processing like transesterification. The emissions and engine performance of diesel engines fuelled with biodiesels have been examined by many investigators [8]. The biodiesels used in the experiments performed by these investigators were produced from different vegetable oils such as sunflower, rapeseed, soybean, karanja, rubber seed, etc. Altiparmak et al. [9] reported that emissions of CO, smoke, HC and PM exhibits a reduction trend with biodiesel and blends of biodiesel diesel fuels compared to pure diesel fuel in expense of higher NO x emissions. However, there are some investigations reporting that the power output increases and NO x emissions decrease with the use of biodiesel. The differences in power and NO x emissions can be attributed to the engine modifications, the fuelling method, exhaust gas treatment, test procedures and test conditions. The engine performance with the biodiesel and the vegetable oil blends of various origins was similar to that of the neat diesel fuel with nearly the same brake thermal efficiency, showing 666

3 higher specific fuel consumption. The experimental results especially on emissions of various studies are not uniform and show different results as can be seen in the literature. In the present work, we intend to produce CNSL biodiesel from the waste cashew nut shell and improve the fuel s properties with ethanol additive. fuel and a blend of CNSL biodiesel 2% by volume mixed with ethanol additive in the volume ratio of 5, 1, and 15 percentages were tested in a direct injection diesel engine at full load conditions. 2. MATERIALS AND METHODOLOGY Mallikappa et al. [4] concluded that using 2% blend of CNSL biodiesel with diesel would give the anticipated results, so 2% blend is taken for analysis. Some authors narrate introduction of additives would improve the drawback of bio oil and therefore in this study ethanol is taken as additive and observed the performance and emissions in C.I engine. The CNSL biodiesel is utilized to prepare the blends, the volume ratio of CNSL biodiesel and diesel, 2/8 is called, and the volume ratio of blend and 5%, 1%, 15% of ethanol is called +E5, +E1, and +E15 respectively. The properties of biodiesel and blends are given in Table 1. Table 1 Properties of the fuel blends. Properties No-2 B1 Kinematic Viscosity cst Density kg/m Lower Heating Value MJ/kg Cetane Number Flash Point o C The engine used is Kirloskar make single cylinder, naturally aspirated, four stroke, water cool, 16.5:1 compression ratio, direct injection diesel engine, and the maximum engine power is 3.7 kw at 15 rpm. A Kirloskar A.C Generator with resistance bank loading arrangement is also incorporated. The outlet temperatures of cooling water and exhaust gas were measured directly from the thermocouples (Cr Al) attached to the corresponding passages. The engine exhausts NO, CO, HC, CO 2 were measured with AVL-444 Di gas analyzer, and the exhaust emissions were measured at 25 mm from the exhaust valve and it specifications are given in Table 2. The smoke opacity was measured by AVL-437C smoke meter after reducing the pressure and temperature in the expansion chamber. The performance and emission characteristics were evaluated for three trails and average are taken for analysis. 667

4 Table 2 Gas analyzer specifications Measured quantity Measuring Range / Resolution Accuracy CO 1 % Volume /.1 % Volume ±.3% Volume CO 2 2 % Volume /.1 % Volume ±.4% Volume HC 2 PPM/1 PPM /1 PPM ±1 PPM O 2 22 % Volume /.1 % Volume ±.1% Volume NO 5 PPM/1 PPM ±5 PPM 3. RESULTS 3.1 Engine Performance The Brake Specific Fuel Consumption (BSFC) was found to increase with the increasing proportion of biodiesel blends with diesel, whereas it decreased sharply with increase in load for all blends. For biodiesel and various percentages of ethanol blends, the BSFC are higher than that of diesel. The increase of BSFC can be explained by Lei Zhu et al. [1] this is because the lower calorific value with increases in ethanol percentage in the blends compared with diesel fuel. The brake thermal efficiency (BTE) obtained for different volumetric blends were recorded in Figure 1. In general, the BTE reduced marginally with the increasing concentration of ethanol in the blends. This could be attributed to the presence of increased amount of oxygen in the blends, which might have resulted in its improved combustion as compared to pure diesel, hence the brake thermal efficiencies comes very close to that of diesel [11]. In general the exhaust gas temperature (EGT) increases with increase in engine loading for all the fuels tested. This increase in exhaust gas temperature with load is obvious from the simple fact that more amount of fuel was required in the engine to generate that extra power needed to take up the additional loading. But exhaust gas temperature was found to decrease with the increasing concentration of ethanol in the blends. Avinash Kumar Agarwal [12] gave the conclusion by increasing percentage of ethanol giving rise to cooling effect in the combustion process. 668

5 3 25 BTE (%) E5 5 +E1 +E15 BMEP(MPa) Figure 1 Comparison of BTE variation with load and fuel blends. 3.2 Engine Exhaust Emission The variation of Carbon monoxide (CO) emissions with engine loading for different fuels is compared in Figure 2. The CO emitted by 5%, 1% and 15% addition of ethanol with biodiesel blends increase by 4, 5 and 64 percentages respectively while comparing.this can be explained by the enrichment of oxygen owing to the ethanol and biodiesel addition, in which an increase in the proportion of oxygen will promote the further oxidation of CO during the engine exhaust process [13]. At the medium loads of engine, test fuels showed lower CO emissions. It can be attributed to the enriched O 2 in the combustion chamber accompanied by sufficient turbulence created by increased mean piston speed. At higher engine loads, inadequate time for complete combustion results in more CO emissions. One can also observe from this figure that the +E1 blend fuel tend to produce lower exhaust CO values than higher ethanol blend CO (%) E5 +E1 +E15 BMEP(MPa) Figure 2 Comparison of CO variation with load and fuel blends. 669

6 The variation of Carbon dioxide (CO 2 ) emissions with engine loading for different fuels is compared in Figure 3. The results indicate that lower CO 2 concentration in exhaust gases was obtained with and ethanol 5 and 1 percentage blend. This is probably because of the lower carbon content of biodiesel fuels. The reduction of CO 2 concentration was higher at low engine loads [14]. At full load, the reduction of CO 2 for E5 and E1 are 29 and 27 % comparing with, but it increased by 7% at the same condition for with E15 blend. For blend, the emission of CO 2 is higher compared all fuel blends and this is due to better combustion in the combustion chamber. CO 2 (%) BMEP (MPa) +E5 +E1 +E15 Figure 3 Comparison of CO 2 variation with load and fuel blends. HC is an important parameter for determining the emission behavior of the engines. It is observed from Figure 4, the 15% ethanol blend with give relatively higher HC emissions as compared to at high engine loads the value is about 43% increase. At low engine loads, the HC emissions tend to increase because of the quench layer of unburned ethanol present in the combustion chamber. In addition to that, the higher latent heat of vaporization of ethanol results in low gas temperature environment, which is the main factor to produce HC emissions. The lowest percentage of HC emission was observed at 5% ethanol blend with at full load, this is because of better combustion inside the combustion chamber. 67

7 HC(PPM) E5 +E1 +E15 BMEP (MPa) Figure 4 Comparison of HC variation with load and fuel blends. The Nitrogen Oxide (NO) content in exhaust emissions of engine for various percentages of ethanol addition in, are plotted as a function of load in Figure 5. From this figure, it can be seen that the NO emission decreases remarkably by 59%, 57%, 32% for 5% 1%, 15% ethanol blends with, respectively at full load conditions. The NO level was found to be directly related to the exhaust temperature. This may be explained that when ethanol blended with the cooling effect of ethanol can lead to reduction of NO emission. On the other hand, the higher oxygen content of ethanol and more fuel burned in premixed burning phase might result in high temperatures and high NO formation [15] NO (PPM) E5 +E1 +E15 BMEP(MPa) Figure 5 Comparison of NO variation with load and fuel blends. 671

8 The smoke content from the engine using biodiesel and its blends with diesel is shown in Figure 6, as a function of engine load versus smoke opacity percentage. From this figure, it can be seen that blend produced less smoke than pure diesel. The minimum and maximum smoke densities produced for and + E15 at full load is 79% and 95%. This could be due to the presence of oxygen molecule in the biodiesel chain, which enhanced its complete burning as compared to diesel. On the other hand, higher smoke opacity was observed at higher ethanol blends as the load increases, due to smoke emission influenced by the cooling effect. Also, when the engine load is increased, more fuel is consumed and more fuel is burned in the diffusion mode [16]. Smoke Opacity (%) BMEP (MPa) +E5 +E1 +E15 Figure 6 Comparison of smoke opacity variation with load and fuel blends. 4. DISCUSSION AND CONCLUSION The CNSL bio oil is cheaper than the other kinds of vegetable oils, which is an important advantage for biodiesel production. Some fuel properties of such as cetane number, Calorific value, sulphur content, and flash point are better than those of diesel fuel. In addition, ethanol as additive improves the density and the viscosity. Exhaust gas emission for 1% ethanol blend reduces CO 2 emission by 27%, HC emission by 8% and NO emission by 57% at full load than that of. The smoke opacity slightly decreases while comparing with diesel and slightly increases compared with. In general, low NO and CO 2 emissions were measured with the 1% ethanol as additive in blend. Therefore Cashew nut shell liquid blends can be used in CI engines in rural area for meeting energy requirement in various agricultural operations such as irrigation, harvesting, threshing, etc; Hence CNSL can be alternately used as fuel for diesel engine. Consequently 2% CNSL biodiesel and 1% ethanol as additive can effectively be used in diesel engines without any modification. 672

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