Performance and Emission Characteristics of a DI Compression Ignition Engine Operated on Marine Fish- Oil Biodiesel Reddy Rana Prathap1,*, Godiganur Sharanappa1 1Department of Mechanical Engineering, Reva Institute of Technology and Management, Yalahanka, Bangalore *Email ID: principal@revainstitution.org
Abstract The high viscosity of vegetable oils leads to problem in pumping and spray characteristics. Biodiesel is recognized as a clean alternative fuel or as a fuel additive to reduce pollutant emissions from combustion equipment. Because cultivated land is too limited to grow seed- oil plants sufficient to produce both food and biodiesel, non-land-based oleaginous materials have been considered important sources for the production of the latter. In this study, fish-oil biodiesel blends are used as fuel. Marine fish oil was extracted from the discarded parts of mixed marine fish and refined. The refined marine fish oil was then transesterified with methyl alcohol to produce biodiesel, which was used thereafter as engine fuel to investigate its engine performance and emission characteristics. This paper presents the results of investigations carried out on a single-cylinder, four stroke, direct-injection, CI engine operated with methyl ester of fish-oil. The volumetric blending ratios of biodiesel with conventional diesel fuel were set at 0, 10, 20, 40, 60, 80, and 100. Engine performance (brake specific fuel consumption, brake specific energy consumption, thermal efficiency and exhaust gas temperature) and emissions (CO, HC and NOx) were measured. The maximum thermal efficiency for B20 (32.28%) was higher than that of diesel at rated load. The experimental results show that the engine performance are close to the values obtained from diesel fuel and the amount of exhaust emissions are lower than those of diesel fuel. Top Keywords Performance, Thermal efficiency, Single cylinder, Emissions, Fish biodiesel. Top |
Introduction Biodiesel that is derived from animal fat, vegetable oil, or used cooking oil has noteworthy fuel characteristics, including a high flash point, outstanding biodegradability, excellent lubricity, and superior combustion efficiency in comparison with the fuel characteristics of petro diesel [1]. Cultivated land is generally too limited to grow enough seed-oil plants, such as rapeseed, soybean, sunflower, and non-edible oils, among others, for biodiesel production, particularly in countries with high population density like India. The price of raw oil is the most dominant factor in the cost of biodiesel fuel, and determines the competitiveness of biodiesel with fossil fuel in the fuel market. To search for a low–cost raw material with adequate fuel characteristics for biodiesel production is an important step towards establishing a successful biodiesel industry. |
The annual production quantity of marine fisheries in Taiwan amounted to 1209 thousand metric tons in 2007 [2]. During the manufacturing process of fish products, the viscera, fins, eyes, tails etc., are often discarded. The discarded parts of marine fish are frequently ground into fishmeal to provide food for livestock and have little economic value. However, the crude fish oil extracted from these discarded parts may provide an abundant, cheap, and stable source of raw oil to allow maritime countries to produce biodiesel and thus help to reduce pollutant emissions [3]. |
Sehmus et. al. [4] conducted performance and emission tests on a single cylinder DI diesel engine with blends of 50% oil and results were compared with diesel fuel. The experimental results showed that the engine power and torque are closer to the values, obtained with diesel as fuel and the amount of exhaust emissions are lower than those of diesel fuel. Canakci [5] investigated the impact of biodiesel prepared from yellow grease, on engine performance and exhaust emissions. Comparisons were made with biodiesel from soybean oil and diesel. They reported nitrogen oxides increased by 11.6% for the YGME and 13.1% for SOME, along with significantly lower CO (17.8% & 18.2%), unburned HC (46.3% and 42.5%). Banapurmath et. al.[6] worked with different methyl esters like Karanja, Jatropha and Sesame oils to investigate comparative measure of BSFC, BTE and emission characteristics. The investigation showed that, engine performance in terms of higher brake thermal efficiency and lower emissions (HC CO NOx) with sesame oil methyl ester operation was observed compared to methyl esters of honge and jatropha oil operation. Godignaur et al.[7] tested methyl ester of fish oil on Kirloskar HA394 DI Diesel engine to evaluate fish biodiesel as an alternative fuel. Gvidonas et al.[8] tested single cylinder DI diesel engine with various blends of RME and diesel. |
Top Experiments Biodiesel Production Crude marine fish oil is used as the raw oil for the production of fish-oil biodiesel. The pretreated marine fish oil is mixed with methanol via a mechanical homogenizer to undergo a transesterification reaction at 600C for one hour. The molar ratio of the preheated oil and methanol was set at 1:6, and 1% wt sodium hydroxide of the fish oil was added into the mixture as an alkali catalyst to enhance this reaction. After the transesterification reaction, the chemical product was separated into two layers, crude biodiesel and glycerin, by keeping it motionless or centrifuging it by virtue of the density difference between the two compounds. The crude biodiesel was then water-washed for five minutes, and the unreacted methanol, water, volatile compounds and other impurities were removed by heating it at 1050C for 10 min. The resulting marine fish-oil biodiesel was thereafter used as diesel engine fuel in the study. Fuel Properties The test fuel sample of fish oil biodiesel was obtained directly from Tinna Oils & Chemicals Ltd Latur (India), manufacturers and suppliers of karanja and fish oil biodiesel to TATA Motors. The physical characteristics of fish oil methyl ester are closer to diesel oil. The fuel properties were tested in Bangalore Test House Bangalore (India), and listed in Table 1. Experimental Set Up A single cylinder, four strokes, water cooled, compression ignition engine with a bore 80 mm and stroke of 110 mm and a compression ratio of 16.5:1 was used for the experimental work. The engine was rated for 5 HP at 1500 rpm with centrifugal governor to control the speed. The performance and exhaust emission tests were carried out in a constant speed, direct injection diesel engine. The engine specifications are represented in Table 2. The engine was loaded with electrical resistive load. Fuel consumption was volumetrically measured using metering burette; the consumption was determined by measuring the time for the consumption of a fixed fuel volume. The air flow was measured using an orifice flow meter and the exhaust gas temperatures were recorded with chromel-alumel thermocouples. The engine was started on neat diesel fuel and warmed up. The warm up period ends when the cooling water temperature was stabilized. The Kirlosker, engine is one of the widely used engines in agriculture tractor, pump sets, farm machinery and medium scale commercial purposes. Experimental Procedure The engine was started by battery with diesel fuel and it was allowed to reach its steady state (for about 10 minutes). The test fuels used during this program were neat (100%) fish biodiesel, a neat (100%) diesel fuel, and blends of 10, 20, 40, 60 and 80 percent biodiesel by volume in the diesel fuel. Selected properties for fuels are listed in Table 1. The engine was sufficiently warmed up and stabilized before taking all readings. The performance of the engine and emissions were studied at variable loads corresponding to the load at maximum power at an average speed of 1500 rpm. After the engine reached the stabilized working condition, load applied, fuel consumption, brake power and exhaust temperature were measured from which brake specific fuel consumption, brake specific energy consumption and thermal efficiency were computed. The emissions such as CO, HC, and NOx were measured using an automotive emission analyzer QRO – 402 exhaust gas analyzer. These performance and emission characteristics for different fuels are compared with the result of baseline diesel. Each reading was obtained thrice to obtain a reasonable value. Top Results and Discussions Biodiesel has low heating value (8% lower than diesel) on weight basis, because of presence of substantial amount of oxygen in the fuel but at the same time biodiesel has a higher specific gravity (0.88) as compared to diesel (0.85) so overall impact is approximately 5% lower energy content per unit volume. The engine performance with fish biodiesel was evaluated in terms of brake specific fuel consumption, brake specific energy consumption, brake thermal efficiency and exhaust gas temperature at different loading conditions of the engine. |
Brake Specific Fuel Consumption (Bsfc) The variation in BSFC with load for different fuels is presented in figure 2. The specific fuel consumption when using a biodiesel fuel is expected to increase in relation to the consumption with diesel fuel. BSFC decreased sharply with increase in load for all fuels. The main reason for this could be that percent increase in fuel required to operate the engine is less than the percent increase in brake power due to relatively less portion of the heat losses at higher loads. As the BSFC was calculated on weight basis, obviously higher densities resulted in higher values for BSFC. The heat content of pure B100 was lower than diesel by about 8%. Due to these reasons, the BSFC for other blends, namely B40, B60, B80 and B100 were higher than that of diesel. Brake Specific Energy Consumption (Bsec) Brake specific energy consumption (BSEC) is an ideal variable because it is independent of the fuel. Hence, it is easy to compare energy consumption rather than fuel consumption. The variation in BSEC with load for all fuels is presented in figure 3. In all cases, it decreased sharply with increase in percentage of load for all fuels. The main reason for this could be that percent increase in fuel required to operate the engine is less than the percent increase in brake power due to relatively less portion of the heat losses at higher loads. Brake Thermal Efficiency The variation of brake thermal efficiency with load for different fuels is presented in figure 4. In all cases, it increased with increase in load. This was due to reduction in heat loss and increase in power with increase in load. The maximum thermal efficiency for B20 (32.28%) was higher than that of diesel. The brake thermal efficiency obtained for B40, B60, B80 and B100 were less than that of diesel. This lower brake thermal efficiency obtained could be due to reduction in calorific value and increase in fuel consumption as compared to B20. This blend of 20% also gave minimum brake specific energy consumption. Hence, this blend was selected as optimum blend for further investigations and long-term operation. In the literature, researchers have concluded that, the thermal efficiency of diesel engines is not appreciably affected when substituted diesel by biodiesel fuel either pure or blended. Exhaust Gas Temperature The variations of EGT with respect to engine loading are presented in figure 5. In general, the EGT increased with increase in engine loading for all the fuel tested. The mean temperature increased linearly from 1440C at no load to 1870C at full load condition. This increase in exhaust gas temperature with load is obvious from the simple fact that more amount of fuel was required to the engine to generate that extra power needed to take up the additional loading. The exhaust gas temperature was found to increase with the increasing concentration of biodiesel in the blends. Carbon Monoxide Variation of CO emissions with engine loading for different fuel is compared in figure 6.The minimum and maximum CO produced was 0.04–0.19%. These lower CO emissions of biodiesel blends may be due to their more complete oxidation as compared to diesel. Some of the CO produced during combustion of biodiesel might have converted into CO2 by taking up the extra oxygen molecule present in the biodiesel chain and thus reduced CO formation. It can be observed from fig.6 that the CO initially decreased with load and latter increased sharply up to full load. This trend was observed for all the fuel blends tested. Initially, at no load condition, cylinder temperature might be too low, which increase with loading due to more fuel injected inside the cylinder. At elevated temperature, performance of the engine improved with relatively better burning of the fuel resulting in decreased CO. Hydrocarbon The hydrocarbon (HC) emission trends for blends of methyl ester of mahua oil and diesel are shown in figure 7. The reduction in HC was linear with the addition of biodiesel for the blends tested. These reductions indicate the more complete combustion of the fuel. The presence of oxygen in the fuel was thought to promote complete combustion. There is a reduction from 44 ppm to 24 ppm resulting in a reduction of 45% as compared to diesel at the maximum power output. Nitrogen Oxides The variation of NOx with engine load for different fuels tested is presented in figure 8. The nitrogen oxides emissions formed in an engine are highly dependent on combustion temperature, along with the concentration of oxygen present in combustion products. When compared with that of pure diesel. In general, the NOx concentration varies linearly with the load of the engine. As the load increases, the overall fuel-air ratio increases resulting in an increase in the average gas temperature in the combustion chamber and hence NOx formation, which is sensitive to temperature increase. Top Conclusions We have experimented upon and have used fish biodiesel for investigation in single cylinder diesel engine. The detailed conclusions drawn from the present investigations are discussed in the corresponding chapters. Some of the important conclusions are presented and are as follows.
The properties like density, viscosity, flash and fire point of fish biodiesel under test are higher, and calorific value is lower, and are in the range of 92–97% that of diesel. The maximum thermal efficiency, minimum brake specific fuel consumption, and minimum brake specific energy consumption of B20 of fish biodiesel is respectively 1.75% lower, 0.004 kg/kW-h higher, and 112.55 kJ/kW-h higher than that of diesel. Emissions like unburnt HC of neat biodiesel at rated load are lower than that of diesel when test is conducted on single cylinder diesel engine. It was observed that the increase in NOx over 32.12% when neat fish biodiesel tested in single cylinder diesel engine. Based on the above discussion and experimental investigations it may be concluded that biodiesel can be adopted as an alternative fuel for the existing diesel engines.
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Top Figures | Figure. 1.: Layout of experimental setup with instrumentation
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| | Figure. 2: Comparison of BSFC with BP for diesel, fish oil biodiesel and its blends
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| | Figure. 3.: Comparison of BSEC with BP for diesel, fish oil biodiesel and its blends
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| | Figure. 4: Comparison of BTE with BP for diesel, fish oil biodiesel and its blends
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| | Figure. 5: Comparison of BSEC with BP for diesel, fish oil biodiesel and its blends
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| | Figure. 6: Comparison of CO with BP for diesel, fish oil biodiesel and its blends
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| | Figure. 7: Comparison of HC with BP for diesel, fish oil biodiesel and its blends
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| | Figure. 8: Comparison of NOx with BP for diesel, fish oil biodiesel and its blends
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Tables | Table 1.: Fuel properties of diesel oil, methyl ester of fish oil
| | Properties | Diesel | Fish oil biodiesel | | Density Kg/m3 | 850 | 880 | | Specific gravity | 0.85 | 0.88 | | Kinematic viscosity | | | | at 400C.(Cst) | 3.05 | 4.0 | | Calorific Value (KJ/kg) | 42800 | 42241 | | Flash Point 0C. | 56 | 176 | | Fire Point 0C. | 63 | 187 |
| | | Table 2.: Engine specification
| | Make | Kirloskar | | Type | Four stroke, single cylinder, water cooled, naturally aspirated, direct injection and vertical | | Rated power | 3.75 KW at 1500 rpm | | Bore and stroke | 80 mm & 100 mm | | Injection timing | 27 deg bTDC | | Std injection pr. | 190 bar |
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