Abstract
In this work, crude palm oil was produced by the single-step distillation of alkali trans-esterification process to provide pure palm oil biodiesel (POB) fuel. The pure POB fuel was improved by using repeated-distillation process in order to apply effectively in 4-cylinders high-speed diesel engine. The influences of pure POB and improved POB on exhaust emission from internal combustion engine were studied under the comparison with commercial diesel fuel. The physical properties of all tested fuels were characterized under ASTM. The experimental results show that the POB fuel yielded at 84.54% under consuming raw materials of 400 grams. Fuel viscosity of improved POB fuel can provide the effective improvement under criterion value of the ASTM standard (≤ 8.0 cSt.) for high-speed engine as compared with pure-POB fuel. The Kinematic viscosity values are of 121.41% and 35.71% for pure POB and improved POB, respectively, which are more than commercial diesel fuel by 8.02% and 7.41%, respectively. Similarity of cetane index values of all tested POB fuel are under ASTM standard, which are less than the diesel fuel by 28.98% and 26.72%, respectively. Heating value of all tested POB provided less value than the diesel fuel. Meanwhile, exhaust emission from the tested engine at 2,000 - 3,000 rpm was studied under using different POB fuels. It shows at 2,000 rpm the effective decrease of CO2 by 1.6% and 3.69% for using pure POB and improved POB, respectively, while 3,000 rpm CO2 decreased by 3.41% and 11.67% for using pure POB and improved POB, respectively as compared with using commercial diesel fuel. CO results show the same reduction trend with CO2 emission. However, NOx emission results show a small amount of increase in exhaust by 1.73% and 0.06% from the engine at 2,000 rpm and by 3.30% and 2.86% from the engine at 3,000 rpm using pure POB and improved POB, respectively as compared with using diesel fuel. Meanwhile, improved POB fuel can relieve the increase of HC emission of pure POB by 76.45% and 18.37% from the engine at 2,000 rpm and by 30.56% and 3.73% from the engine at 3,000 rpm, respectively. This study suggests that improved POB fuel has the high potentiality for as a clean and alternative fuel.
