Methanol production from fermentor off-gases. Final report, July 1, 1981-June 30, 1982. [CDH-methanol process]

The off-gases from an acetone-butanol fermentation facility are composed mainly of CO/sub 2/ and H/sub 2/. Such a gas stream is an ideal candidate as a feed to a methanol synthesis plant utilizing modern technology recently developed and known as the CDH-methanol process. A detailed economic analysis for the incremental cost of a methanol synthesis plant utilizing the off-gases from an acetone-butanol fermentation indicates a profitable rate of return of 25 to 30% under the most likely production conditions. Bench-scale studies at different fermentor mixng rates indicate that the volume of gases released during the fermentation is a strong function of the agitation rate and point to a potential interaction between the volume of H/sub 2/ evolved and the levels of butanol present in the final fermented broth. Such interaction may require establishing optimum operating conditions for an integrated butanol fermentation-methanol synthesis plant.