Modeling and simulation of biodiesel production using a membrane reactor integrated with a prereactor

To enable the transesterification performed as quickly as possible, whereas the purification of product simultaneously carried out as completely as possible, the biodiesel production using a membrane reactor integrated with a prereactor is developed in this work. The set of mathematical model equations for the whole system includes the kinetics of the transesterification, the phase equilibrium, the mass balance of the prereactor, and the equations for the tubular ceramic membrane derived from mass balances of both the feed side and the permeate side coupled with the mass transfer across the membrane. The integrated reactor performances are then investigated in terms of the permeated biodiesel flux and selectivity over a range of methanol to oil ratio in the feed, the initial reaction time in the prereactor, the volume ratio of the prereactor to the tube membrane, and the length of the tube membrane module. The results show that the prereactor can be used for the purpose of carrying out a substantial part of the transesterification reaction in the early stage. The subsequent membrane reactor, when the operating conditions are controlled at methanol to oil molar ratio in the feed of 24:1, the catalyst concentration to the oil of 0.05 wt% at 65 oC, can serve to separate the unreacted emulsified oil from the product stream. The production of biodiesel with high purity using this proposed system is further validated experimentally and found in agreement considerably well with the simulated ones by adjusting the operating conditions, including the initial reaction time in the prereactor and the tube membrane length.

► Model equations for the prereactor and the tubular membrane are derived.
► The performances of the integration of the above modules are investigated.
► An experiment is carried out to confirm the simulation results of the proposed models.
► Experiments prove the applicability of the proposed integrated system.