8 sonuçlar
Arama Sonuçları
Listeleniyor 1 - 8 / 8
Öğe Biodiesel properties of microalgae (Chlorella protothecoides) oil for use in diesel engines(Taylor & Francis, 2018-09-08) Yaşar, Fevzi; Altun, ŞehmusIn this study, biodiesel was produced from a microalgae oil, chlorella protothecoides, by typical alkali-catalyzed transesterification in conditions such as a 0.75 wt.% KOH of the oil as catalyst, 68°C and 80 min which was agreed as optimal conditions after investigating the effect of KOH concentration, reaction temperature and time at constant molar ratio of 6:1 on the conversion rate and fuel properties. Under these conditions, a 98.6% conversion rate of algae oil to its methyl ester was achieved with ester content higher than 96%. Furthermore, all physicochemical properties met the requirements of international biodiesel standards, EN 14214 and ASTM D 6751, with some remarkable ones such as high cetane number (57.3) and low CFPP (−10°C). The effect of microalgae biodiesel volume fraction in the fuel on the kinematic viscosity, CFPP, lubricity, density, and distillation temperature was also studied. A blending ratio of the algal-biodiesel up to 50% (v/v) was also found in agreement with the standards for biodiesel-diesel blends. From GC analysis, oleic and linoleic acids were found to be major fatty acids, and then the oxygen extended sooting index and adiabatic flame temperature were calculated using fatty acid distribution for evaluating the main diesel emissions such as soot and NO. As a result, the algae oil studied here was found to be an appropriate raw material for producing biodiesel and for using in Diesel Engines and its properties are within the typical ranges of conventional biodiesel fuels.Öğe Biofuels derived from Turkish industry wastes - A study of performance and emissions in a diesel engine(Wiley-Blackwell, 2015-08-13) Altun, Şehmus; Rodríguez-Fernández, JoséRecently, research has focused on the biofuel production from local industrial wastes due to the risk of greenhouse emissions derived from land-use change (both directly and indirectly) of conventional feedstock and the social concern about the effect of conventional biofuel production on oil prices and its availability (the so-called food vs. fuel debate). Therefore, with the aim to evaluate the use of biofuels derived from wastes from traditional manufacturing industries in Turkey, biodiesel fuels from leather fat, obtained as a by-product in the leather industry, waste anchovy fish oil, derived from the fish-processing industry, and waste frying cottonseed oil achieved from food industry, have been tested in a three-cylinder DI diesel engine at a steady-state condition. In a previous work, the viability of these fuels was evaluated by analyzing measured and estimated properties and indicators for main diesel emissions, and recommendations were made on their alternative use to conventional biodiesels with the benefit of potentially lower life-cycle greenhouse emissions. The experimental results, which were compared with ULSD operation, demonstrated that the engine performance was not significantly affected, while a substantial change in emissions was observed with the use of biofuels. In general, the emission results reported here are in a similar range to those obtained with the use of conventional biodiesel fuels. Nonetheless, the exact magnitude of these changes depended upon the biodiesel origin. Lubricity of alternative biofuels was also tested, revealing an enormous capacity for protecting the fuel system from wear, in line with conventional biodiesel fuels.Öğe Effects of thermal barrier coating on the performance and combustion characteristics of a diesel engine fueled with biodiesel produced from waste frying cottonseed oil and ultra-low sulfur diesel(Taylor & Francis, 2016-09-01) Aydın, Selman; Sayın, Cenk; Altun, Şehmus; Aydın, HüseyinIn this study, the top surfaces of piston and valves of a four-strokes and direct-injection diesel engine have been coated—with no change in the compression ratio—with a 100 μm of NiCrAl lining layer via plasma spray method and this layer has later been coated with main coating material with a mixture of 88% of ZrO 2 , 4% of MgO and 8% of Al 2 O 3 (400 μm). Then, after the engine-coating process, ultra-low sulfur diesel (ULSD) as base fuels and its blend with used frying cottonseed oil derived biodiesel in proportion of 20%, volumetrically, have been tested in the coated engine and data of combustion and performance characteristics on full load and at different speeds have been noted. The results, which were compared with those obtained by uncoated-engine operation, showed that thermal efficiency increased, and engine noise reduced. Cylinder gas pressure values obtained from the diesel engine which has been coated with thermal barriers have been found to be somewhat higher than those of the uncoated-engine. Also, maximum pressure values measured in both engines and under the same experimental conditions through the use of test fuel have been obtained after TDC. Moreover, heat release rate and heat release have occurred earlier in the coated-engine. NOx emissions were increased while CO and HC emissions were remained almost the same with a little bit decrease.Öğe Biodiesel production from leather industry wastes as an alternative feedstock and its use in diesel engines(SAGE, 2013-11-01) Altun, Şehmus; Yaşar, FevziWaste leather fat is produced by the leather industry in fleshing processing and discarded as waste. These wastes can be used as a potential feedstock for biodiesel production due to their considerable fat content. In this work, raw fleshing oil which is a fat-originated waste of the leather industry was transesterified using methanol in the presence of an alkali catalyst to obtain biodiesel. The obtained biodiesel was then used in a four-stroke and direct injection diesel engine to evaluate the biodiesel behavior as an alternative diesel fuel, at a constant speed under variable load conditions. Blends [20 and 50% (v/v)] of biodiesel with diesel reference fuel were tested too. The emissions test results compared with diesel reference fuel showed that diesel engine fueled by biodiesel emitted significantly lower opacity and gaseous emissions than the same engine fueled by diesel reference fuel, and with very similar performance. The obtained data indicated that biodiesel from leather industry wastes is promising as an alternative fuel for diesel engines, and can be used to substitute diesel fuel in terms of performance and emission parameters without any engine modification.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 using bioethanol as fuel on start-up and warm-up exhaust emissions from a diesel power generator(Taylor & Francis, 2021-09-01) Altun, Şehmus; Adin, Mehmet Şükrü; Adin, Muhammed ŞakirThe present work investigates the effects of bioethanol as fuel additive on a diesel power generator’s exhaust emission (especially under transient conditions) characteristics, during the start-up followed by idling and warm-up periods, from no load to loaded cases up to 50% at ambient conditions. Experiments with diesel/bioethanol blends in 10% and 15% proportions (denoted as BE10 and BE15, respectively) were achieved in a diesel power generator following the practical operating conditions of the gen-sets. Regarding emissions, CO increased first when bioethanol is used during start-up at no load, then it starts to decrease by increasing bioethanol fraction in diesel and load applied. Unburnt HC emissions were also measured as highest for all fuels tested during start-up, while they were slightly higher for BE15 than others in the rest of the test. NOx was highest with petroleum diesel, while it was lowest with BE15 at start-up. Despite higher NOx was measured with BE10, those of petroleum diesel and BE15 were similar during warm-up together with applying load. Smoke opacity was lowest in BE15; however, BE10 was highest. By applying load, it increased and the highest NOx was measured with BE10, while the lowest was with BE15.Öğe Effect of biodiesel addition in a blend of isopropanol-butanol-ethanol and diesel on combustion and emissions of a CRDI engine(Taylor & Francis, 2021-05-21) Altun, Şehmus; İlçin, KutbettinThe increasing demand for energy and the fact that petroleum, which is the most used energy source, has a limited reserve, have led researchers to search for new and renewable energy sources. In this context, biofuels such as biodiesel and bio alcohols have been studied and used in internal combustion engines for a long time. However, with the developments in technology, the production and use of such alternative fuels in different engine technologies is still a subject of research. In this regard, isopropanol-butanol-ethanol (IBE) has received an increasing attention over standard alcohols and its potential as a substitute for other alcohol fuels in internal combustion engines has been researched recently. Therefore, the purpose of the experimental study is to investigate the effect of biodiesel addition at rates of 20% and 40% by volume in a blend of IBE (30% v/v) with petroleum-based diesel (70% v/v) on the combustion and emission characteristics of a single-cylinder common-rail direct injection engine at constant engine speed of 2400 rpm and 60% load conditions. Experimental results showed that all blended fuels presented a potential to reduce smoke opacity by 27% − 41%, CO emissions by 44% − 66% and unburnt HC emissions (up to 31.8%) but increase NOx emissions by 5% − 24.6% compared to diesel. However, adding biodiesel caused to a slight increase in smoke opacity and CO emissions while decrease in unburned HC and NOx emissions compared to the blend of IBE and diesel. Combustion analysis also showed that the use of blended fuels led to the increase of peak cylinder pressure (by 7%) and the significant improvement in the rate of heat release was observed, which further increased with the addition of biodiesel to blend of IBE and diesel. It was concluded that ternary blends was performed better than the blend of IBE and diesel while biodiesel addition was found to be beneficial in terms of reduction of unburnt HC and NOx emissions along with improved performance.Öğe Emissions from a diesel power generator fuelled with biodiesel and fossil diesel fuels(SAGE Journals, 2015-08-01) Altun, ŞehmusThe aim of this work was to compare the emission characteristics of a biodiesel derived from waste cooking sunflower oil and two fossil diesel fuels (ultra-low sulphur diesel and its type of containing gas-to-liquid). The tests were conducted on a direct-injection diesel engine-powered generator set, which is the type of generator applied in institutional facilities, under variable load and constant engine speed conditions. Experimental results showed that diesel containing gas-to-liquid and biodiesel reduced smoke opacity while NOx emissions were slightly higher for both fuels. An increase in fuel consumption was also observed for biodiesel compared with both fossil diesels. Unburned HC emissions were high for biodiesel, but overall level of CO emissions remained very low for all fuels tested
