Simulation study of biobutanol production in a polymer-loaded two-phase partitioning bioreactor (PL-TPPB): Model development

The conventional two-phase partitioning bioreactor (TPPB) containing an organic solvent as a second phase was found to be hardly efficient for biobutanol production because of the relatively low partitioning coefficient of butanol between the organic solvent and aqueous solution. Polymer bead was alternatively employed as the second phase in the TPPB, and Dowex Optipore L-493, a copolymer of styrene and divinyl benzene, was chosen as the optimum polymer because it shows the highest partitioning coefficients of butanol, acetone, ethanol and butyric acid against the aqueous phase among candidate polymers. The mass transfer coefficients of compounds from the aqueous phase into polymer beads were experimentally determined with respect to agitation speed. The mass transfer coefficient related to the stripping of volatile compounds by nitrogen gas was also determined, and the influence of gas flow rate turned out to be greater than that of the agitation speed, though both influences were remarkable. A mathematical model for the TPPB containing the polymer beads was suggested and as many as 40 parameters were cited from other publications or determined in this study. This mathematical model will be subsequently used for the detailed simulation study.