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 concentration 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 about 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 about 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gas phase from said bioreactor assembly at said at least one gas outlet wherein the substrate depleted gas phase being withdrawn from the bioreactor assembly has a partial pressure of carbon dioxide in the range of about 2.5 and 25 kPa; and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.
9 Citations
22 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 concentration 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 about 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 about 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 about 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)
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16. A process for controlling the operation of a bioreactor assembly 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 wherein:
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a. said 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 menstruum, said bioreactor having at least one gas inlet and at least one gas outlet in which at least one bioreactor is characterized as having a substantially uniform aqueous menstruum and a substantially non-uniform substrate concentration between the gas inlet and the gas outlet; b. contact is maintained between the gas bubbles and said menstruum to provide an alcohol-containing menstruum and a substrate depleted gas phase at a gas outlet portion of said bioreactor assembly; c. substrate depleted gas phase is continuously withdrawn from said bioreactor assembly at the at least one gas outlet; and d. a portion of said menstruum is continuously or intermittently withdrawn 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, with the process further comprising adjusting the ratio of electrons to carbon atoms gas bubbles at said gas inlet portion to be within in the range of about 5.2;
1 to 6.8;
1 and adjusting the carbon dioxide concentration in the gas substrate to provide a partial pressure of carbon dioxide in the substrate depleted gas phase at the at least one gas outlet portion to be in the range of about 2.5 and 25 kPa. - View Dependent Claims (17, 18, 19, 20)
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21. A continuous processes for the anaerobic bioconversion of a syngas comprising carbon monoxide, hydrogen, carbon dioxide and nitrogen in an aqueous menstruum containing microorganisms suitable for converting said substrate to alcohol comprising:
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a. continuously reforming a hydrocarbonaceous feedstock by autothermal reforming using air as the source of oxygen for the autothermal reforming, said autothermal reforming being operated to provide a syngas having an electron to carbon atom ratio of between about 5.5;
1 and 6.0;
1 and a nitrogen concentration of between about 25 and 35 mole percent;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 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 concentration between the gas inlet and the gas outlet; b. maintaining contact between the gas bubbles and said menstruum to provide an alcohol-containing menstruum 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 95 percent of the carbon monoxide in the gas substrate to alcohol; c. continuously withdrawing 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 has a partial pressure of carbon dioxide in the range of about 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 (22)
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Specification