Design of a Batch Stirred Fermenter for Ethanol Production

This paper addresses the batch stirred bioreactor design for ethanol production with yeasts Saccharomyces cerevisiae under anaerobic conditions carried out to improve the performance of the fermentation process. A large, appropriate – sized fermenter is supposed 70 m3. The operating volume is 52,5 m3. Batch fermentation was perform with 200 g/l glucose concentration. Fermentation time, is 11,4 hours with ethanol stripping 69,1 g.l-1 and 12 hours 75,9 g.l-1 without stripping. Computing is stopped when glucose alteration obtain 97 percent. The kinetic constants (Ks, Kp, μmax) of batch fermentation were 2,0 kg.m-3, 97,9 kg.m-3, 0,476 h-1 respectively. Output per a batch is 3 623 kg and a single fermenter can produce 514 batches per year. From it follows that the year vintage is close to the actual 1 862 222 kg. Therefore, the number of 70 m3 fermenters required 4 bioreactor. Whole heat exchange and heat surface area estimated 338437 J/s and 40 m2 respectively. The maximum yield of biomass on substrate (YX/S) and the maximum yield of product on substrate (YP/S) in batch fermentation were 82% and 35,5% respectively. The present research has shown that high sugar concentration (200 g/l) in the batch stirred bioreactor was successfully converted to ethanol. The achieved results in batch stirred bioreactor with high substrate concentration are promising for scale up operation. The proposed model can be used to design a larger scale batch stirred bioreactor for production of high ethanol concentration.