Biodiesel production from soapstock of palm oil refining

The production of fatty acid ethyl esters from palm oil soapstock, a by-product of vegetable oil refining, was conducted. The process involved alkaline hydrolysis of all lipid-linked fatty acid ester bonds with sodium hydroxide solution (50 %) concentration followed by drying to about 8.5 wt% of water content. The resulting fatty acid sodium salts was pulverized, screened to 0.5 mm mesh and then esterified by acid catalyzed esterification process in the presence of sulfuric acid. The reaction parameters effects on the esterification reaction were studied in terms of temperature and ethanol to soapstock molar ratio. Three temperatures were investigated 55°C, 65°C and 75°C and three molar ratios of 10:1, 25:1 and 35:1 under incubation time varied from 30–120 min. The results revealed that maximum biodiesel yield can be achieved under 75°C of reaction temperature, 35: 1 of molar ratio and 120 min of reaction time. GC-MS results revealed that fatty acids ethyl esters content is 98.69 wt% dominated by ethyl palmitate with weight content above 88 %.