Improvement of Pour Point of Biodiesel Fuel and Its Diesel Combustion

In order to use bio-butanol instead to methanol at biodiesel production, and to reduce the pour point of biodiesel, 1-butyl esters and isobutyl esters of coconut oil, palm oil, rapeseed oil and soybean oil were produced by using 1-butanol and isobutanol. The experimental results show that when the molecule structure becomes more branching type, the pour point of biodiesel decreases, and the effect of the pour point depressant addition increases. Also, the combustion characteristics and exhaust emissions of rapeseed oil biodiesels were investigated using a DI diesel engine. Although the 1-butyl ester and isobutyl ester have slightly higher HC, CO and Smoke emissions compared to the methyl ester, they have same thermal efficiency and lower HC and Smoke emissions compared to JIS no.2 gas oil. Addition of pour point depressants up to 0.3 mass% has no effect on heat release rate, thermal efficiency, and exhaust emissions.