A.M. Ashraful

Stability of biodiesel, its improvement and the effect of antioxidant treated blends on engine performance and emission

Biodiesel consists of long chain fatty acid esters derived from vegetable oils, animal fats, and used oils. Biodiesel contains different types, amounts, and configurations of unsaturated fatty acids, which are prone to oxidation. Biodiesel stability is affected by its interaction with atmospheric oxygen, light and temperature, storage conditions, and factors causing sediment formation. It can be classified broadly into three types: oxidation stability, thermal stability, and storage stability. Oxidative degradation occurs in biodiesel upon aerobic contact during storage, as well as upon contact with metal contaminants. Thermal instability focuses on the oxidation rate at higher temperatures, which is characterized by the formation of insolubles and increase in the weight of oil and fat. Storage stability is concerned with interaction between the physical and chemical characteristics of biodiesel with environmental factors, such as light, metal contamination, color changes, and sediment formation. Antioxidant concentration greatly influences engine performance and emission. The BSFC of biodiesel fuel with antioxidants is less than that of fuel without antioxidants. Moreover, an antioxidant can significantly reduce NOx formation during engine operation. Among the available synthetic antioxidants, only three antioxidants (TBHQ, PY, and PG) can significantly increase biodiesel stability. This article presents an overview of the stability of biodiesel, including the methods available for the prediction of its different stability properties. Feasible remedies to improve the stability of biodiesel and the effect of antioxidants in stabilized blends on engine performance and emission are also discussed.

Performance and emission characteristics of a compression ignition engine running with linseed biodiesel

The energy crisis facing the world today is the result of the continuous depletion of fossil fuels caused by high usage demand. To alleviate the situation, researchers and scientists have been searching for low-cost, eco-friendly, and readily available substitutes to fossil fuel. Biodiesel can be a promising alternative source of energy. This study investigated the parameters of a direct-injection water-cooled diesel engine run with linseed biodiesel blends. These parameters include brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE), and emission characteristics. Then, the performance of this engine was compared with that of a diesel fuel-run engine by evaluating the BSFC, BTE, and mechanical efficiency. Results show that the BSFC decreases as the load increases for all fuel blends and increases as the percentage of biodiesel in the blend increases; a 25.6% increase in BSFC is obtained at a low load. The BTE increases with increasing load; at a low load, the highest reduction in BTE is 15.38%. The CO emission reduces by approximately 5.49% at a low load for the B30 blend and 27.7% at a high load for the B20 blend compared with diesel. For pollution investigation, the emissions of NOX, HC, and CO were measured. The CO emission reduces by approximately 5.49% while HC and NOX emissions respectively increase by 15.8% and 19.5% at a low load.

Performance and Emission of a CI Engine Using Antioxidant Treated Biodiesel

Biodiesel has been a promising clean alternative fuel to fossil fuels, which cuts the emissions that are released by fossil fuels, and perhaps reduces the energy crisis induced by the exhaustion of oil resources in the near future. In this study, the effect of antioxidant additive on engine performance and emission characteristics of an engine fueled with palm biodiesel was investigated and compared with conventional diesel fuel. For this study, four fuel samples including pure diesel, diesel-biodiesel (B20), diesel-biodiesel-additive (B20+additive) and pure biodiesel (B100) were used in a multi cylinder, four stroke, water cooled, direct injection diesel engine. Engine tests were performed at various engine speed of 1000 rpm to 4000 rpm with 50% throttle opening. Engine performance and emission concentrations are investigated by determining the break specific fuel consumption (BSFC), brake thermal efficiency, CO, HC, NOx and smoke opacity using gas analyzers. The results showed that the use of baynox plus solution as additive with palm methylester gave average 3.10% higher brake power as well as 23.2% and 2.40% lower NOx and brake specific fuel consumption than the biodiesel blend without additives.

Impact of edible and non-edible biodiesel fuel properties and engine operation condition on the performance and emission characteristics of unmodified DI diesel engine

ABSTRACT The purpose of this work is to test the feasibility of biodiesel as a substitute for diesel used in a direct injection (DI) diesel engine. The biodiesel was produced by an esterification and transesterification process. Experiments were conducted with diesel–biodiesel blends containing 10 and 20% biodiesel with the diesel fuel. The results of the biodiesel blends are compared with baseline diesel which was assessed at constant speed in a single cylinder diesel engine at various loading conditions. The physicochemical properties of palm and Calophyllum inophyllum biodiesel and their blends meet the standard specification ASTM D6751 and EN 14214 standards. The maximum brake thermal efficiency was attained with diesel fuel, 10% palm biodiesel (PB10) and 10% C. inophyllum biodiesel (CI10) at all load condition except low load condition. Engine emission results showed that the 20% C. inophyllum with 80% diesel blend exhibited 6.35% lower amount of brake specific carbon monoxide, and the PB20 blend and CI20 blend reduced brake specific hydrocarbon emission by 7.93 and 9.5%, respectively. NOx emission from palm and C. inophyllum biodiesel blends are found to be 0.29–4.84% higher than diesel fuel. The lowest smoke intensity is found at 27.5% for PB10 and CI10 biodiesel blends compared with diesel fuel.

Comparative Study of Properties and Engine Performance Using Blend of Palm and Coconut Biodiesel

Now-a-days the demand of alternative fuel is continuously increasing all over the world due to the rapid depletion of fossil fuel and increased global demand. Biodiesel is renewable and sustainable energy source derived from vegetable oils and animal fats which can be the best substitute of fossil fuel. This paper investigates the property of different biodiesel such as palm, coconut and their blends with conventional diesel also analyzed the engine performance like engine break power, speed, break specific fuel consumption (BSFC), torque in diesel engine. In this paper 20% palm biodiesel with diesel (P20), 20% coconut biodiesel with diesel (C20), 30% palm biodiesel with diesel (P30), 30% coconut biodiesel with diesel (C30) and combination of 15% palm biodiesel and 15% of coconut biodiesel with diesel (C15P15) were used for study. Biodiesel was produced by using transesterification process. The density and kinematic viscosity for C15P15 fuel is slightly higher and flash point is slightly lower than diesel fuel as well as others two biodiesel blends whereas pure palm oil biodiesel shows the higher flash point and acid value. Engine performance test was carried out at 75 kg load condition with variable speeds of 1400 rpm to 2000 rpm at an interval of 200 rpm. Engine brake power produced by mixed biodiesel (C15P15) is slightly lower than the fossil diesel but slightly higher than biodiesel (only palm or coconut). Engine torque produce by the mixed biodiesel is almost the same with the fossil diesel but higher than the others biodiesel blends. Engine brake specific fuel consumption of mixed biodiesel is slightly higher than fossil diesel but lower than others existing biodiesel. It can be reported that the fuel C15P15 showed better performance and can be used as fuel alternative to diesel fuel to reduce the greenhouse gas emission and dependency on crude oil.