PROCESSES FOR ENHANCING THE PERFORMANCE OF LARGE-SCALE, TANK ANAEROBIC FERMENTORS

摘要

Processes are disclosed for the low energy, anaerobic bioconversion of hydrogen and carbon monoxide in a gaseous substrate stream to oxygenated organic compounds such as ethanol by contact with microorganisms in a deep, tank fermentation system with high conversion efficiency of both hydrogen and carbon monoxide. Gas feed to the reactor is injected using a motive liquid to form a stable dispersion of microbubbles thereby reducing energy costs, and a portion of the off-gases from the reactor are recycled to (i) achieve a conversion of the total moles of carbon monoxide and hydrogen in the gas substrate to oxygenated organic compound of at least about 80 percent and (ii) attenuate the risk of carbon monoxide inhibition of the microorganism used for the bioconversion.

主权项

1. A process for bioconverting CO, H2 and CO2 to oxygenated organic compound comprising:
a. passing a gas feed comprising CO, H2 and CO2 into in a reactor containing aqueous menstruum under aerobic fermentation conditions, said aqueous menstruum containing microorganisms adapted for bioconverting syngas to oxygenated organic compound, to produce oxygenated organic compound dissolved in the aqueous menstruum and an off gas; b. maintaining in said primary reactor a depth of aqueous menstruum of at least 10 meters; c. maintaining in said reactor a head space above the upper portion of the aqueous menstruum; d. continuously supplying the gas feed to said aqueous menstruum through a plurality of injectors that use a motive liquid to form a stable gas-in-liquid dispersion in at least a lower portion of the aqueous menstruum; e. modulating the microbubble size to control the rate of transfer of the carbon monoxide and hydrogen to aqueous menstruum and provide a stable gas-in-liquid dispersion; and, f. bioconverting carbon monoxide and hydrogen and carbon dioxide to an oxygenated organic compound and providing off-gas from the aqueous menstruum in the head space.