Processes and control systems for high efficiency anaerobic conversion of hydrogen and carbon oxides to alcohols
First Claim
1. A continuous process for the anaerobic bioconversion of a gas substrate comprising carbon monoxide, hydrogen and carbon dioxide in an aqueous menstruum containing microorganisms suitable for converting said substrate to alcohol comprising:
- a. continuously introducing said substrate in the form of gas bubbles at one or more gas inlets of a bioreactor assembly having at least one bioreactor for containing said menstruum, 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 menstruum and a substantially non-uniform substrate between the gas inlet and the gas outlet wherein the cumulative substrate introduced into the bioreactor assembly through said one or more gas inlets has a ratio of electrons to carbon atoms in the range of 5.2;
1 to 6.8;
1;
b. maintaining contact between the gas bubbles and said menstruum to provide an alcohol-containing menstruum and a substrate depleted gas phase at a gas outlet of said bioreactor assembly, said duration of contact being sufficient to convert at least 80 percent of the hydrogen in the gas substrate to alcohol;
c. continuously withdrawing 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gas phase from said bioreactor assembly at said at least one gas outlet wherein the substrate depleted gas phase being withdrawn from the bioreactor assembly has a partial pressure of carbon dioxide in the range of 2.5 and 25 kPa; and
d. continuously or intermittently withdrawing a portion of said menstruum from said bioreactor assembly for recovery of said alcohol, said withdrawal being sufficient to maintain the alcohol in said menstruum below a concentration that unduly adversely affects the microorganisms.
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Accused Products
Abstract
High conversion efficiency processes are disclosed for the anaerobic bioconversion of syngas to alcohol. The processes use bioreactors that have a non-uniform gas composition and a substantially uniform liquid composition such as deep tank bioreactors. By maintaining certain electron to carbon mole ratios in the syngas feed to the bioreactors and certain partial pressures of carbon dioxide in the off gas from the bioreactors, at least about 80 percent of the hydrogen and at least about 95 percent of the carbon monoxide in the feed can be consumed.
2 Citations
17 Claims
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1. A continuous process for the anaerobic bioconversion of a gas substrate comprising carbon monoxide, hydrogen and carbon dioxide in an aqueous menstruum containing microorganisms suitable for converting said substrate to alcohol comprising:
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a. continuously introducing said substrate in the form of gas bubbles at one or more gas inlets of a bioreactor assembly having at least one bioreactor for containing said menstruum, 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 menstruum and a substantially non-uniform substrate between the gas inlet and the gas outlet wherein the cumulative substrate introduced into the bioreactor assembly through said one or more gas inlets has a ratio of electrons to carbon atoms in the range of 5.2;
1 to 6.8;
1;b. maintaining contact between the gas bubbles and said menstruum to provide an alcohol-containing menstruum and a substrate depleted gas phase at a gas outlet of said bioreactor assembly, said duration of contact being sufficient to convert at least 80 percent of the hydrogen in the gas substrate to alcohol; c. continuously withdrawing 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 has a partial pressure of carbon dioxide in the range of 2.5 and 25 kPa; and d. continuously or intermittently withdrawing a portion of said menstruum from said bioreactor assembly for recovery of said alcohol, said withdrawal being sufficient to maintain the alcohol in said menstruum below a concentration that unduly adversely affects the microorganisms. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification