Sulfur management for processes and control systems for the efficient anaerobic conersion of hydrogen and carbon oxides to alcohols
AssigneeCoskata, Inc.
InventorRichard E. Tobey
Life of this patent
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Abstract
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.
Claims20
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gas phase from said bioreactor assembly at said at least one gas outlet wherein the substrate depleted gas phase being withdrawn from the bioreactor assembly contains hydrogen sulfide;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.
A process for controlling the operation of a bioreactor assembly 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 wherein:
- a. the gas substrate is continuously introduced in the form of gas bubbles 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 in and at least one bioreactor characterized as having a substantially uniform aqueous broth and a substantially non-uniform substrate concentration between the gas inlet and the gas outlet;
- b. contact is maintained with the microorganisms, the gas bubbles and said broth to provide an alcohol-containing broth and a substrate depleted gas phase at least one gas outlet of said bioreactor assembly;
- c. the substrate depleted gas phase, which contains hydrogen sulfide, is continuously withdrawn from said bioreactor assembly at the at least one gas outlet;
- d. a portion of said broth is continuously or intermittently withdrawn 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;
- e. at least a portion of hydrogen sulfide from the depleted gas phase is contacted with a sulfite compound to convert the hydrogen sulfide to form sulfur compounds which are beneficial to microorganisms in the bioreactor;
- and
- f. at least a portion of the sulfur compounds is introduced to at least one or more inlets of a bioreactor assembly,
- with the process further comprising adjusting a rate of introduction of the sulfur compounds to the at least one or more inlets of a bioreactor assembly.
A continuous processes for the anaerobic bioconversion of a syngas 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 reforming a hydrocarbonaceous feedstock to provide a syngas;
- b. continuously introducing said syngas in the form of gas bubbles 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 and at least one bioreactor in the bioreactor assembly is characterized as having a substantially uniform aqueous broth and a substantially non-uniform substrate concentration between the gas inlet and the gas outlet;
- b. maintaining contact of the microorganisms with the gas bubbles and said broth to provide an alcohol-containing broth and a syngas depleted gas phase at a gas outlet of said bioreactor assembly, said duration of contact being sufficient to convert at least about 90 percent of the hydrogen and at least about 98 percent of the carbon monoxide in the gas substrate to alcohol;
- c. continuously withdrawing a syngas depleted gas phase from said bioreactor assembly at said at least one gas outlet wherein the syngas depleted gas phase being withdrawn from the bioreactor assembly contains hydrogen sulfide;
- d. 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;
- e. converting at least a portion of the hydrogen sulfide from the depleted gas phase to thiosulfate;
- f. passing the thiosulfate to the bioreactor through at least one or more inlets of the bioreactor assembly.
Dependencies are inferred from the claim text.