Biodiesel Produced from Soybean Oil with the Two Flow Reactors in Series

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.  In our research, viscous soybean oil is converted to less viscous FAME biofuels with methanol and honeycomb monolithic catalysts in a two-flow reactor assembly in series at moderate temperatures and pressures to develop monolithic catalysts for efficient methanol transesterification processes.

Reaction mixtures from the first catalytic flow reactor consist of biodiesel (fatty methyl esters), glycerol, unreacted soybean oil, and excess methanol.  Glycerol is removed from reaction mixtures from the first catalytic flow reactor to feed the second catalytic flow reactor.  Reaction mixtures of biodiesel and unreacted soybean oil produced from the first catalytic flow reactor are fed into the second catalytic flow reactor to increase yields of biodiesel by shifting equilibrium conversion of soybean oil in favor of increasing conversion of soybean oil into biodiesel.  Active and stable monolithic catalysts are formulated with various active metals and honeycomb monolithic catalyst supports to produce FAME biofuels from soybean oil.