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Öğe Performance and exhaust emissions of a DI diesel engine fueled with waste cooking oil and inedible animal tallow methyl esters(TÜBİTAK, 2011) Altun, ŞehmusThe performance and exhaust emissions of a direct injection diesel engine were experimentally investigated using 2 biodiesel fuels with promising economic perspective, one obtained from inedible animal tallow and the other from waste cooking oils. Inedible animal tallow, which is obtained from a mixture of slaughtered cattle and sheep fats collected from a local slaughterhouse during meat preparation process, was transesterified using methyl alcohol and an alkaline catalyst to produce the inedible animal tallow methyl ester. Biodiesel from waste cooking oil was produced from waste cooking oils and methyl alcohol via a transesterification reaction, and provided by a commercial biodiesel producer. In order to investigate the performance and exhaust emissions, the experiments were conducted at different engine speeds under the full load condition of the engine. The experimental results showed, compared with diesel fuel, that the biodiesel fuels resulted in a reduction in brake torque and in an increase in brake specific fuel consumption. Although both biodiesels caused reductions in carbon monoxide (CO), the NOx emissions were higher for waste cooking oil biodiesel and lower for inedible animal tallow biodiesel as compared to diesel fuel.Öğe Hayvansal iç yağlardan transesterifikasyon reaksiyonu ile biyodizel üretilmesi(Doğu Anadolu Bölgesi Araştırma ve Uygulama Merkezi, 2008-07-31) Altun, Şehmus; Öner, CengizHayvansal yağlar normal çevre sıcaklığında katı ve çok viskozdurlar. Yüksek viskozitelerinden dolayı dizel motorlarında kullanılmadan önce modifiye edilmeleri gerekmektedir. Hayvansal yağların dizel motorlarında kullanılabilirliliğini iyileştirmek için emülsiyon ve transesterifikasyon etkili iki yöntemdir. Bu çalışmada hayvansal iç yağlardan baz katalizörlü transesterifikasyon ile %99.7 saflıkta metil alkol ve katalizör olarak %98 saflıkta NaOH kullanılarak hayvansal iç yağı metil esteri (biyodizel) üretilmiştir. Hayvansal iç yağı, metil ester şekline dönüştükten sonra viskozitesi önemli ölçüde azalmış ve oda sıcaklığında sıvı fazında bir yakıt elde edilmiştir. Biyodizelin belirlenen yakıt özellikleri ASTM standartlarında olup, viskozitesi ve yoğunluğu dizel yakıtına yakın, ısıl değeri ise %8 daha düşük çıkmıştır.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 The effect of microalgae biodiesel on combustion, performance, and emission characteristics of a diesel power generator(VINCA Institute of Nuclear Sciences, 2018) Yaşar, Fevzi; Altun, ŞehmusMicroalgae oil is expected to be a relevant source of biofuel in the future as it is more favorable to confront the problems of food shortages and greenhouse emission challenges raised by conventional biofuels. Therefore, in this study, a most common kind of microalgae that have a great potential, Chlorella protothecoides, was evaluated as fuel in terms of its combustion and emission characteristics in a Diesel engine-powered generator set at constant engine speed of 1500 rpm under various loads after converting its oil to biodiesel by typical base-catalyzed transesterification process. A biodiesel/diesel blend at the rate of 20% by volume was tested too. According to results obtained, using biodiesel resulted in an increase in fuel consumption, in a slight reduction of efficiency, and in sharp reductions in both unburned hydrocarbon emissions and smoke opacity especially at light loads, despite increasing NOx emissions were observed when compared with conventional petroleum diesel. In addition, premixed combustion ratio was higher for biodiesel than for diesel while total combustion duration took shorter for biodiesel especially at higher loads. The overall results of the study reveals that the combustion parameters of the biodiesel studied here are within the typical ranges of conventional biodiesel fuels.
