Simulation and energy analysis of the ABE fermentation integrated with gas stripping

This work concerns the recovery of butanol from a batch fermenter, in which the ABE mixture is recovered from the broth by means of gas stripping. The aim of this work is to compare the performances of the integrated fermentation-gas stripping process with those of a conventional batch fermenter. For this purpose, both processes have been modeled and their energy requirements have been determined by means of an energy analysis. Results suggest that the continuous product removal from the fermenter allows to reduce the fermentation time by 50%. Therefore, the process productivity is almost double. At the same time, the total specific energy requirement for the integrated recovery process is almost three times greater than that of the traditional batch process. This is essentially due to the duty required at the condenser for products recovery from the gas stream, as a result of the low concentration of ABE in the recovered stream. Therefore, the application of an integrated recovery process allows to increase the process productivity, but at the expense of an increase in the whole process energy demand.