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Öğe Biodiesel production from inedible animal tallow and an experimental investigation of its use as alternative fuel in a direct injection diesel engine(Elsevier, 2009-02-15) Altun, Şehmus; Öner, CengizIn this study, a substitute fuel for diesel engines was produced from inedible animal tallow and its usability was investigated as pure biodiesel and its blends with petroleum diesel fuel in a diesel engine. Tallow methyl ester as biodiesel fuel was prepared by base-catalyzed transesterification of the fat with methanol in the presence of NaOH as catalyst. Fuel properties of methyl ester, diesel fuel and blends of them (5%, 20% and 50% by volume) were determined. Viscosity and density of fatty acid methyl ester have been found to meet ASTM D6751 and EN 14214 specifications. Viscosity and density of tallow methyl esters are found to be very close to that of diesel. The calorific value of biodiesel is found to be slightly lower than that of diesel. An experimental study was carried out in order to investigate of its usability as alternative fuel of tallow methyl ester in a direct injection diesel engine. It was observed that the addition of biodiesel to the diesel fuel decreases the effective efficiency of engine and increases the specific fuel consumption. This is due to the lower heating value of biodiesel compared to diesel fuel. However, the effective engine power was comparable by biodiesel compared with diesel fuel. Emissions of carbon monoxide (CO), oxides of nitrogen (NOx), sulphur dioxide (SO2) and smoke opacity were reduced around 15%, 38.5%, 72.7% and 56.8%, respectively, in case of tallow methyl esters (B100) compared to diesel fuel. Besides, the lowest CO, NOx emissions and the highest exhaust temperature were obtained for B20 among all other fuels. The reductions in exhaust emissions made tallow methyl esters and its blends, especially B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution. Based on this study, animal tallow methyl esters and its blends with petroleum diesel fuel can be used a substitute for diesel in direct injection diesel engines without any engine modification.Öğe The comparison of engine performance and exhaust emission characteristics of sesame oil-diesel fuel mixture with diesel fuel in a direct injection diesel engine(Elsevier, 2008-01-09) Altun, Şehmus; Bulut, Hüsamettin; Öner, CengizThe use of vegetable oils as a fuel in diesel engines causes some problems due to their high viscosity compared with conventional diesel fuel. Various techniques and methods are used to solve the problems resulting from high viscosity. One of these techniques is fuel blending. In this study, a blend of 50% sesame oil and 50% diesel fuel was used as an alternative fuel in a direct injection diesel engine. Engine performance and exhaust emissions were investigated and compared with the ordinary diesel fuel in a diesel engine. The experimental results show that the engine power and torque of the mixture of sesame oil-diesel fuel are close to the values obtained from diesel fuel and the amounts of exhaust emissions are lower than those of diesel fuel. Hence, it is seen that blend of sesame oil and diesel fuel can be used as an alternative fuel successfully in a diesel engine without any modification and also it is an environmental friendly fuel in terms of emission parameters.Öğe Exhaust emissions of methanol and ethanol-unleaded gasoline blends in a spark ignition engine(VINCA Institute of Nuclear Sciences, 2013) Altun, Şehmus; Öztop, Hakan Fehmi; Öner, Cengiz; Varol, YasinIn this study, the effect of unleaded gasoline and unleaded gasoline blended with 5% and 10% of ethanol or methanol on the performance and exhaust emissions of a spark-ignition engine were experimentally investigated. The engine tests were performed by varying the engine speed between 1000 and 4000 rpm with 500 rpm period at three-fourth throttle opening position. The results showed that brake specific fuel consumption increased while brake thermal efficiency, emissions of carbon monoxide and hydrocarbon decreased with methanol-unleaded gasoline and ethanol-unleaded gasoline blends. It was found that a 10% blend of ethanol or methanol with unleaded gasoline works well in the existing design of engine and parameters at which engines are operating.Öğe Biodiesel production from raw cottonseed oil and its characterization(Energy Education Science and Technolgy Part A, 2011-07) Altun, Şehmus; Yaşar, Fevzi; Öner, CengizIn this study, raw cottonseed oil of Turkish origin was transesterified using methyl alcohol and an alkali catalyst to obtain the cottonseed oil methyl ester. The obtained cottonseed oil methyl ester was analyzed by gas chromatography (GC) for determining the fatty acid composition. The fuel-related properties of cottonseed oil methyl ester, cold filter plugging point, cloud point, kinematic viscosity, density, cetane index, flash point, distillation, sulfur content and heating value were determined and compared with those of petroleum diesel fuel and international biodiesel standards. From gas chromatograph analysis, it was found that the cottonseed oil methyl ester has the more amount of total unsaturated FA, therefore, it showed better cold-flow properties than more saturated ones, as expected. Moreover, the fuel-related properties of cottonseed oil methyl ester were within the specified standardsÖğe Improved combustion of asphaltite coals in a rotating head combustor with various air supply arrangements(ACS Publications, 2014-04-16) Altun, Şehmus; Öner, CengizWhen burned in conventional stokers, coals with high swelling properties such as asphaltites make coke blocks (coking). The plastic layer formed on them prevents air from diffusing into coal; hence, the air provided for swollen coal to burn becomes insufficient. This problem can partially be resolved by shaking the flame bed automatically or by mixing the burning coals manually in order to provide continuous air for the surface of the unburned coal. Therefore, in this study, a coal combustion system with the rotating head was manufactured for burning effectively Turkish coking coals characterized by high sulfur and ash content in agitation conditions with air supply arrangements. This type of coals known as asphaltite, abundantly found in southeastern Anatolia coal basin in Turkey, were burned in the rotating head combustor in order to investigate the effect of operating parameters, such as excess air ratio, coal particle size and feeding speed, air delivery type, addition of flange, bed slope, and rotation speed on the combustion efficiency and temperature distribution on the head. Experimental results showed that both the rotating of combustion chamber and additional air supply, which was blown out with pressure from the air delivery holes, reduced the negative impact of ash on the combustion efficiency, mainly due to the coal getting in touch with air better. It was possible to increase the peak combustion efficiency over 80% by both improving the air supply and agitation of coalbed preventing coking during combustion. As a result, this system could be highly recommended to burn the coals with high swelling properties like asphaltite at a high efficiency.Öğe Comparison of methanol, ethanol, or n-butanol blending with unleaded gasoline on exhaust emissions of an SI engine(Taylor & Francis, 2014-03-18) Altun, Şehmus; Varol, Yasin; Öner, Cengiz; Öztop, Hakan FehmiAir pollution is becoming a serious problem in many urban cities of the world and it can have a serious effect on both health and the environment. Although experimental studies have shown that alcohol fuels burn cleaner than unleaded gasoline and produce lesser emission, there is limited information regarding the comparison among the alcohol fuels as gasoline additive in spark-ignited engines. Therefore, a comparison has been performed in this experimental work on the exhaust emissions of a spark-ignited engine when operating on a blend of methanol, ethanol, or n-butanol with unleaded gasoline. Methanol, ethanol and n-butanol were added to unleaded gasoline by mass percent of 10% (denoted as M10, E10 and Bu10, respectively), and then tested in a four cylinder, four strokes spark-ignited engine. Although the experimental results show little differences in exhaust emissions between M10, E10, and Bu10, compared with Bu10, M10 and E10 have lower carbon monoxide emission and higher fuel consumption, hydrocarbon, and CO2 emission. Compared with unleaded gasoline, blended fuels containing different alcohols appear to have a lower carbon monoxide and hydrocarbon emissions and a higher fuel consumption rate and CO2 emissions.Öğe Effect of n-butanol blending with a blend of diesel and biodiesel on performance and exhaust emissions of a diesel engine(ACS Publications, 2011-06-22) Adin, Hamit; Altun, Şehmus; Yaşar, Fevzi; Öner, CengizExperimental work was conducted to evaluate the effect of using n-butanol (normal butanol) in conventional diesel fuel–biodiesel blends on the engine performance and exhaust emissions of a single cylinder direct injection compression ignition engine with the engine working at a constant engine speed and at different three engine loads. A blend of biodiesel and diesel fuel known as B20 (20% biodiesel and 80% diesel in volume) was prepared, and then n-butanol was added to B20 at a volume percent of 10% and 20% (denoted as B20Bu10 and B20Bu20, respectively). Fuel consumption; regulated exhaust emissions such as nitrogen oxides, carbon monoxide, and total unburned hydrocarbons; and smoke opacity were measured. The brake specific fuel consumption of fuel blends was found to be higher when compared to that of conventional diesel fuel. On the other hand, the addition of n-butanol to the B20 fuel blend caused a slight increase in the brake specific fuel consumption and brake thermal efficiency in comparison to the B20 fuel blend. For exhaust emissions, carbon monoxide (CO) and hydrocarbon (HCs) emissions decreased, and NOx remained almost unchanged at low engine loads, while it decreased at high engine loads. Fuel blends also resulted in a sharp reduction of smoke opacity in the whole range of engine tests.Öğe Flue gas emissions from the burning of asphaltite and lignite in a rotating head combustor with secondary air delivery(ACS Publications, 2014) Altun, Şehmus; Öner, CengizIn this work, a rotating head combustor, which has been designed for burning the coking coals effectively, was deployed to burn a range of coals available in Turkey under agitation conditions with secondary air delivery. The coals were lignite (Tunçbilek, Turkey) and asphaltite with high swelling property known as coking coal (Şırnak, Turkey). The performance was investigated by determining the temperature distribution on the head, combustion efficiency, and the amount of unburned substances (such as C) in the ash, and flue gas emissions of O2, CO, CO2, SO2, and NOx were measured during the experiments. The effect of operating conditions such as excess air ratio (EAR) and coal feeding rate was also investigated. The temperature distribution on the head was found to be high in the case of using the secondary air delivery and combustion efficiency was above 80% at the EAR of 1.3 and coal feeding rate of 9 kg/h when asphaltite was used as the fuel in the rotating head combustor. The comparison between asphaltite and lignite could lead to the conclusion that asphaltite provides slightly higher efficiency than lignite, and the difference is very small at the EAR of 1.3. When flue gas emissions are compared, it is seen that CO and SO2 emissions from asphaltite combustion are higher while CO2 and NOx emissions are lower than those derived from lignite combustion. For the combustion of both fuels, secondary air sent to the bed surface had a noticeable influence on combustion and emission characteristics via its effect on the combustion of volatility products and released gases from the bed surface. However, it should be more for lignite combustion in order to get better performance.Öğe Gaseous emission comparison of a compression-ignition engine fueled with different biodiesels(Islamic Azad University of Research and Technology, 2012-12-14) Altun, Şehmus; Öner, CengizIn this study, it was performed a comparison of the performance and emissions of two methyl ester fuels: one obtained from animal fat and the other from crude canola oil, in a compression-ignition engine against diesel fuel. The experimental results compared with diesel fuel showed that significant reductions could be obtained by biodiesel derived from animal fat in carbon monoxide and oxides of nitrogen emissions. Carbon dioxide emissions showed a trend of decreasing with the biodiesel fuels. An increase in brake specific fuel consumption was observed for different biodiesel fuels when compared with diesel fuel. It was concluded that animal tallow methyl ester performed better than canola oil methyl ester, whereas slightly higher brake torque is observed with canola oil methyl ester.
