AN INTEGRATED MEMBRANE- BASED SYSTEM FOR PRODUCTION AND SEPARATION OF BUTANOL

Abstract

In alcoholic fermentation, the substrate conversion rate is limited by substrate inhibition, product inhibition or both as it has been discovered in the present work. The present work deals with the study of butanol fermentation with C. acetobutylicum of whey 46 g/1 lactose, and then separation by pervaporation. In the present study, the effect of the initial substrate concentration of (46-65-1 00) gil and cells concentration (0.2-1-2) g/1 on the fermentation process were studied. Versions of models developed to describe batch butanol fermentation with free cells. The models incorporate linear product inhibition, substrate inhibition and both amalgamated substrate and product inhibition. Both the predicted values of both substrate and alcohol concentrations show good agreement with the experimental values. The kinetic constants of the biocatalyst were determined by each developed model version for each case. The pervaporation as a membrane tool of separation was also studied. A pervaporation cell was designed and manufactured at the National Research Center workshops. This cell was used to separate the butanol from binary system (butanol I water) at different initial butanol concentrations (6-8-11-16 20-50) g/1. A resistance in series model was used to study the pervaporation step. The butanol concentration in the feed tank for such pervaporation cell was determined by developing a model )Yhich was achieved through the two ways, which are global and detailed approaches. Good agreement was achieved between the predicted and the experimental values obtained. The integrated butanol fermentation and pervaporation was economically evaluated for a small unit of 400 ton I year capacity, the capital costs and production costs were determined. The proposed integrated system is recommended to be a new technology to produce butanol via fermentation economically.