Energy balance of ethanol production with a gas-solid fluidized bed fermenter

Research on gas-solid fluidized bed fermenters has been performed since the early 1980's. This new type of fermentation system is applicable in the production of volatile substances with inhibiting effects upon the bioreaction and in the production of specific metabolites in a solid-state mode. The fluidized bed fermenter system provides excellent mass and heat transfer and allows fermentation to take place under water-reduced conditions (1). This paper delivers the theoretical results achieved the production of ethanoly by Saccharomyces cerevisiae in a fluidized bed fermentation system including recirculation of the fluidizing gas and coolers for ethanol recovery. The influence of the parameters governing process control, i.e. reactor productivity, ethanol concentration in the gas phase and in the condensate, and the specific energy consumption, are shown. The energy requirement is compared to that of conventional systems for ethanol production.