SULFUR MANAGEMENT FOR PROCESSES AND CONTROL SYSTEMS FOR THE EFFICIENT ANAEROBIC CONERSION OF HYDROGEN AND CARBON OXIDES TO ALCOHOLS

摘要

High conversion efficiency processes are disclosed for the anaerobic bioconversion of syngas to alcohol by microorganisms having metabolic processes that utilize sulfur in limited amounts. The processes remove hydrogen sulfide from the gas leaving the bioreactor assembly by forming sulfur compounds that are beneficial to the microorganisms. The sulfur compounds can be returned to the bioreactor assembly to meet a portion of microorganism sulfur demand.

主权项

1. In a continuous process for the anaerobic bioconversion of a gas substrate comprising at least one of carbon monoxide and hydrogen with carbon dioxide in an aqueous broth containing microorganisms, the microorganisms having metabolic processes that utilize sulfur in limited amounts and being suitable for converting said substrate to alcohol comprising:
a. continuously introducing said gas substrate at one or more gas inlets of a bioreactor assembly having at least one bioreactor for containing said broth, said bioreactor having at least one gas inlet and at least one gas outlet; b. maintaining contact of the microorganisms with the gas substrate and said broth to provide an alcohol-containing broth and a substrate depleted gas phase at the at least one gas outlet of said bioreactor assembly, said duration of contact being sufficient to convert at least about 80 percent of any carbon monoxide in the gas substrate to alcohol; c. continuously or intermittently withdrawing a portion of said broth from said bioreactor assembly for recovery of said alcohol, said withdrawal being sufficient to maintain the alcohol in said broth below a concentration that unduly adversely affects the microorganisms; d. continuously withdrawing the substrate depleted gas phase from said bioreactor assembly at said at least one gas outlet wherein the substrate depleted gas phase being withdrawn from the bioreactor assembly contains hydrogen sulfide; e. converting at least a portion of the hydrogen sulfide from the substrate depleted gas phase to form sulfur compounds that include sulfur compounds that are beneficial to microorganisms in the bioreactor; and f. introducing at least a portion of the sulfur compounds to at least one or more inlets of the bioreactor assembly.