Effects of Acid Catalyst Types and Concentrations on Free Fatty Acid Reduction in Mixed Crude Palm Oil using Continuous Static Mixer

Free fatty acid (FFA) in mixed crude palm oil (MCPO) must be reduced to less than 1 wt.% or 2 mgKOH.g(-1) of acid value by the acid-catalyzed esterification process when the base-catalyzed transesterification was used to produce the biodiesel for the two-stage process. This study was to investigate the effects of acid catalyst types: sulfuric acid (H2SO4), phosphoric acid (H3PO4), and hydrochloric acid (HCL) at 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 vol.% of acid catalyst concentration on the reduction of acid value in MCP by the continuous static mixer. Results indicated that H2SO4 has the most significant variable affecting the acid value in MCPO. The acid catalyst concentration of 1.0 and 1.5 vol.% H2SO4 can reduce the acid value to less than 2 mgKOH.g(-1) with 15 vol.% of methanol and 5-meter in the length of static mixer, while both H3PO4 and HCL could not reduce the acid value was reduced to less than 2 mgKOH.g(-1). Moreover, the results clearly indicated that HCL has the lowest significance effect on the acid value reduction in MCPO by the esterification reaction.