An experimental investigation on performance and emission characteristics of a diesel engine generator using a mix- ture of jatropha oil and rubber seed oil biodiesels along a two-step transesterification

Abstract

Biodiesel can be produced from edible and non-edible vegetable oils; however, the edible oils compete with the food supply leading to economic imbalance. This study investigates the ex- traction of seed oils, production of biodiesels from non-edible oils, characterization, and per- formance and emission characteristics of engine-generator fueled with various dual biodiesel blends prepared from two non-edible feedstock jatropha and rubber. Non-edible vegetable oils from jatropha and rubber seeds were extracted by a mechanical press operated hydraulically and then purified through an acid degumming process. Jatropha and rubber oils had high acid values which were 13.96 mg KOH/g and 27.91 mg KOH/g respectively. Therefore, a two-step transesterification process was carried out to reduce the acid value to 0.28 mg KOH/g and 0.42 mg KOH/g for jatropha and rubber respectively. The physicochemical properties of biodiesels produced were in agreement with the ASTM D6751 and EN14214 standards. The engine gen- erator performance and emissions of various mixed biodiesel–diesel blends (BC10, BC20, BC30, and BC40) were investigated and compared with B0, BA20, and BB20 biodiesel blends. The experiment was performed on a single-cylinder, four-stroke, direct injection, and air- cooled YANMAR brand (Model: YDL 4200) diesel engine that was equipped with a generator under a constant speed of 3000 rpm and varying load conditions of 0 W, 500 W, 1000 W, 1500 W, and 2000 W. In general, a blend of jatropha and rubber biodiesel resulted in a reduction in density and viscosity compared with rubber biodiesel and improved ignition quality compared with jatropha biodiesel. At maximum load, The SFC for the dual biodiesel blend (BC20) was close to that of diesel and BC40 had a higher air/fuel ratio than diesel and other blends. Dual biodiesel blends reduced CO 2 , CO, and HC emissions as compared with diesel, while NO X emission was higher. The experimental results indicate that better engine-generator perfor- mance and emission characteristics of the fuel was observed with the BC20 blend followed by BC40 and can be successfully used as an alternative fuel in diesel engine generators without any modification