RECOVERY OF BUTANOL FROM ABE FERMENTATION BROTH BY GAS STRIPPING: PROCESS SIMULATION AND TECHNO-ECONOMIC EVALUATION

The production of butanol through the ABE fermentation is of great interest because of the growing demand for renewable fuels. The major limit for an industrial-scale production of bio-butanol is the high separation cost, due to its low final concentration in the broth, which results from inhibition of the microorganism by products. The application of an integrated recovery technique able to remove butanol during fermentation is a viable solution for improving the economics of the ABE fermentation. In this context, gas stripping appears to be a promising recovery technique. Several literature experimental studies on lab-scale gas stripping units are available, but few deal with process simulation. This work presents a process configuration for the recovery of butanol from a batch fermenter, in which the product is recovered from the broth by means of gas stripping and subsequently fractionated in a distillation train, simulated in Aspen Plus (R). The model of the integrated fermentation-gas stripping process has shown the beneficial effect of product removal on sugar consumption and process productivity at the expense of an increased energy demand, as resulting from the energy analysis carried out to compare the performances of the process including or not gas stripping.