Viscous vegetable oils containing triglycerides of various fatty acids and free fatty acids are mostly converted to less viscous fatty acid methyl esters (FAME) through the methanol trans-esterification process, using homogeneous catalysts in batch reactors. FAME biofuels produced with homogeneous alkali catalysts through transesterifcation processes contain undesirable substances such as soap and homogeneous catalysts in addition to glycerol and water. Additional refining and purification processes are needed to remove these undesirable substances from FAME biofuels, generating wastewater. Viscous soybean oil in methanol is converted to less viscous FAME biofuels with honeycomb monolithic catalysts in a flow reactor at moderate temperatures and pressures to test catalytic activities of monolithic catalysts formulated for efficient methanol transesterification processes.
Active and stable monolithic catalysts were formulated with various active metals and honeycomb monolithic catalyst supports to produce FAME biofuels from soybean oil. Flow reactors with honeycomb monolithic catalysts have some advantages over flow reactors packed/fluidized with catalyst pellets for the transesterification of soybean oil. Pressure drops will be lower over flow reactors with honeycomb monolithic catalysts than those packed with pellet catalysts. High uniform mass transfer rates of methanol and soybean oil to porous surface of solid catalysts will occur in narrow channels of monolithic catalysts in comparison with packed catalyst pellets. Formulated honeycomb monolithic catalysts are deactivated and regenerated during converting soybean oil in methanol to FAME biofuels in a vertical honeycomb monolithic catalyst flow reactor by showing conversion of soybean oil to FAME biofuels fluctuated, that is not observed with powdered/pellet catalysts in a packed or fluidized flow reactor.