Continuous Flow System for the Heterogeneous Catalytic Production of Advanced Biofuels

A continuous-flow catalytic esterification of free fatty acids with methanol in the presence of sulfonated hydrothermal carbon as catalyst was studied. Using a Box-Behnken experimental design protocol the effects of retention time, methanol/acid molar ratio and water concentration on the conversion of oleic acid into methyl oleate in the continuous-flow packed bed reactor were investigated. The optimum conditions for achieving an esterification of greater than 90% was seen at 100 ºC for a 11-minute residence time, a MeOH/FFA molar ratio > 14.6 while in the presence of up to 14.9% water. The SHTC was used continuously for 4.5 days without any significant decrease in catalytic performance. The results confirmed that SHTC is an effective solid acid catalyst in a continuous flow system for the esterification of FFA.

Flow system prototype in operation