Submitted to: American Institute of Chemical Engineers Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: September 2, 2003
Publication Date: September 2, 2003
Citation: Qureshi, N., Dien, B.S., Saha, B.C., Ezeji, T.C., Blaschek, H.P., Cotta, M.A. 2003. Separation of butanol from fermentation broth by pervaporation: mass flux and energy balance [abstract]. American Institute of Chemical Engineers. Paper No. 162B. Technical Abstract: Butanol, a superior liquid fuel, can be produced anaerobically by Clostridium beijerinckii or C. acetobutylicum from agricultural biomass. However, the cultures are strongly inhibited by the butanol. In bioreactors, butanol concentration higher than 25 g/L is rarely reached. Low butanol concentration hampers economic recovery of this fuel. Pervaporation, gas stripping, and liquid-liquid extraction have been reported to be energy efficient techniques for the separation of butanol from fermentation broth. In order to compare the effectiveness of these techniques, we have investigated their use with C. beijerinckii/C. acetobutylicum butanol producing strains. The results of our findings on the use of pervaporation membranes will be presented at the meeting. Several types of membranes were evaluated including polypropylene, silicone, silicalite, and polytetrafluoroethylene (PTFE). The performance of these membranes varied significantly depending upon chemical composition of the membrane and means of removal of butanol vapors from the membrane surface. Butanol vapors were removed from membrane surface either by sweep gas or vacuum. When applied, vacuum offered high flux as compared to sweep gas. Polypropylene membranes offered high flux and low selectivities, while silicone membranes offered low flux and high selectivities. These two types of membranes are easily available. Although silicalite membrane offers high selectivities, they are not easily available.