System for the Production of Methane From CO2

Abstract

A method of converting CO 2 gas produced during industrial processes comprising contacting methanogenic archaea with the CO 2 gas under suitable conditions to produce methane.

1 . A method of converting carbon dioxide produced during an industrial process to methane comprising:
 a) preparing a culture of hydrogenotrophic methanogenic archaea in a bioreactor;   b) supplying an output gas from an industrial process to the bioreactor; wherein the output gas comprises CO 2  and between 0.02% and 6.7% oxygen (moles/volume of output gas); and   c) wherein the hydrogenotrophic methanogenic archaea converts the output gas to continuously produce methane.   
     
     
         2 . The method of  claim 1  wherein the culture is a substantially pure culture of one hydrogenotrophic methanogenic archaea species. 
     
     
         3 . The method of  claim 1  wherein H 2  is supplied in an amount to maintain a redox potential in the bioreactor under −100 mV or less, and wherein no additional constituent other than the H 2  gas is added to the bioreactor to maintain the redox potential in the bioreactor under −100 mV or less. 
     
     
         4 . The method of  claim 1  wherein the industrial process is coal gasification, biomass gasification, or liquid fuel production by biomass fermentation. 
     
     
         5 . The method of  claim 2  wherein the hydrogenotrophic methanogenic archea species is selected from the group consisting of  Methanobacterium alcaliphilum, Methanobacterium bryantii, Methanobacterium congolense, Methanobacterium defluvii, Methanobacterium espanolae, Methanobacterium formicicum, Methanobacterium ivanovii, Methanobacterium palustre, Methanobacterium thermaggregans, Methanobacterium uliginosum, Methanobrevibacter acididurans, Methanobrevibacter arboriphilicus, Methanobrevibacter gottschalkii, Methanobrevibacter olleyae, Methanobrevibacter ruminantium, Methanobrevibacter smithii, Methanobrevibacter woesei, Methanobrevibacter wolinii, Methanothermobacter marburgensis, Methanothermobacter thermautotrophicum, Methanothermobacter thermoflexus, Methanothermobacter thermophilus, Methanothermobacter wolfeii, Methanothermus sociabilis, Methanocorpusculum bavaricum, Methanocorpusculum parvum, Methanoculleus chikuoensis, Methanoculleus submarinus, Methanogenium frigidum, Methanogenium liminatans, Methanogenium marinum, Methanosarcina acetivorans, Methanosarcina barkeri, Methanosarcina mazei, Methanosarcina thermophila, Methanomicrobium mobile, Methanocaldococcus jannaschii, Methanococcus aeolicus, Methanococcus maripaludis, Methanococcus vannielii, Methanococcus voltaei, Methanothermococcus thermolithotrophicus, Methanopyrus kandleri, Methanothermobacter thermoautotroiphicus, Methanocaldococcus fervens, Methanocaldococcus indicus, Methanocaldococcus infernus,  and  Methanocaldococcus vulcanius.    
     
     
         6 . The method of  claim 5  wherein the hydrogenotrophic methanogenic archea is selected from the group consisting of  Methanosarcina barkeri  and  Methanococcus maripaludis.    
     
     
         7 . The method of  claim 6  wherein the conditions include a temperature of about 35° C. to about 37° C. 
     
     
         8 . The method of  claim 5  wherein the hydrogenotrophic methanogenic archea is  Methanothermobacter thermoautotroiphicus.    
     
     
         9 . The method of  claim 8  wherein the conditions include a temperature of about 60° C. to about 65° C. 
     
     
         10 . The method of  claim 5  wherein the hydrogenotrophic methanogenic archea is selected from the group consisting of  Methanocaldococcus fervens, Methanocaldococcus indicus, Methanocaldococcus infernus , and  Methanocaldococcus vulcanius.    
     
     
         11 . The method of  claim 10  wherein the conditions include a temperature of about 80° C. to about 100° C. 
     
     
         12 . The method of  claim 1  wherein the industrial output gas comprises at least 0.8% oxygen (moles/volume of output gas). 
     
     
         13 . The method of  claim 1  wherein the industrial output gas comprises at least 1.7% oxygen (moles/volume of output gas). 
     
     
         14 . The method of  claim 1  wherein the industrial output gas comprises at least 3.4% oxygen (moles/volume of output gas). 
     
     
         15 . The method of  claim 1  wherein the industrial output gas comprises between 3.4% -6.7% oxygen (moles/volume of output gas). 
     
     
         16 . The method of  claim 1  wherein the industrial output gas further comprises carbon monoxide. 
     
     
         17 . The method of  claim 16 , wherein the industrial output gas comprises at least about 8% carbon monoxide by volume. 
     
     
         18 . The method of  claim 16 , wherein the industrial output gas comprises at least about 16% carbon monoxide by volume. 
     
     
         19 . The method of  claim 16 , wherein the industrial output gas comprises at least about 60% carbon monoxide by volume. 
     
     
         20 . A method of converting carbon dioxide produced during an industrial process to methane comprising:
 a) contacting a culture comprising hydrogenotrophic methanogenic archaea with H 2  gas and an output gas from an industrial process comprising CO 2  gas in a bioreactor;   b) supplying an amount of H 2  gas to maintain a redox potential in the bioreactor under −100 mV or less, wherein no additional constituent other than the H 2  gas is added to the bioreactor to maintain the redox potential in the bioreactor under −100 mV or less; and   c) wherein the hydrogenotrophic methanogenic archaea converts the H 2  gas and the CO 2  gas to methane.   
     
     
         21 . A method of converting carbon dioxide produced during an industrial process to methane comprising:
 a) preparing an initial culture of hydrogenotrophic methanogenic archaea and placing the culture in a bioreactor;   b) supplying an output gas from an industrial process to the bioreactor; wherein the output gas comprises CO 2 ;   c) supplying fresh medium to the culture;   d) wherein the hydrogenotrophic methanogenic archaea converts the output gas to continuously produce methane; and   e) wherein no sulfur is added in the method, other than the presence of sulfur in the initial culture.   
     
     
         22 . A method of converting carbon dioxide produced during an industrial process to methane using a cascaded bioreactor process, the process comprising:
 a) preparing a culture of hydrogenotrophic methanogenic archaea, wherein the culture is present in a first and second reactor vessel;   b) supplying fresh medium to the first and second reactor vessels through a first medium feed line attached to the first reactor vessel, and a second medium feed line attached to the second reactor vessel;   c) supplying H 2  gas to the first reactor vessel through hydrogen gas feed line;   d) supplying an output gas from an industrial process to the first reactor vessel; wherein the output gas comprises CO 2 , through an output gas feed line;   e) wherein the hydrogenotrophic methanogenic archaca culture in the first reactor converts H 2  gas and CO 2  gas to produce methane;   f) transferring at least a portion of gas in the first reactor vessel to the second reactor vessel by a first gas feed line;   g) wherein the hydrogenotrophic methanogenic archaea culture in the second reactor converts H 2  gas and CO 2  gas to produce methane.   
     
     
         23 . The method of  claim 22  further comprising:
 a) preparing a culture of hydrogenotrophic methanogenic archaea, wherein the culture is present in a third reactor vessel; 
 b) supplying fresh medium to the third reactor vessels through a third medium feed line attached to the third reactor vessel; 
 c) transferring at least a portion of gas in the second reactor vessel to the third reactor vessel by a second gas feed line; 
 d) wherein the hydrogenotrophic methanogenic archaea culture in the third reactor converts H 2  gas and CO 2  gas to produce methane. 
 
     
     
         24 . The method of  claim 22  wherein the output gas further comprises between 0.02% and 6.7% oxygen (moles/volume of output gas) and wherein the hydrogenotrophic methanogenic archaea in the first and second reactor vessels continuously produce methane. 
     
     
         25 . The method of  claim 22  wherein H 2  is supplied in an amount to maintain a redox potential in the first reactor vessel under −100 mV or less, and wherein no additional constituent other than the H 2  gas is added to the first reactor vessel to maintain the redox potential in the first reactor vessel under −100 mV or less. 
     
     
         26 . The method of  claim 22  wherein no sulfur is in the process other than sulfur in the culture medium. 
     
     
         27 . The method of  claim 22  wherein the hydrogenotrophic methanogenic archca comprises one or more species selected from the group consisting of  Methanobacterium alcaliphilum, Methanobacterium bryantii, Methanobacterium congolense, Methanobacterium defluvii, Methanobacterium espanolae, Methanobacterium formicicum, Methanobacterium ivanovii, Methanobacterium palustre, Methanobacterium thermaggregans, Methanobacterium uliginosum, Methanobrevibacter acididurans, Methanobrevibacter arboriphilicus, Methanobrevibacter gottschalkii, Methanobrevibacter olleyae, Methanobrevibacter ruminantium, Methanobrevibacter smithii, Methanobrevibacter woesei, Methanobrevibacter wolinii, Methanothermobacter marburgensis, Methanothermobacter thermautotrophicum, Methanothermobacter thermoflexus, Methanothermobacter thermophilus, Methanothermobacter wolfeii, Methanothermus sociabilis, Methanocorpusculum bavaricum, Methanocorpusculum parvum, Methanoculleus chikuoensis, Methanoculleus submarinus, Methanogenium frigidum, Methanogenium liminatans, Methanogenium marinum, Methanosarcina acetivorans, Methanosarcina barkeri, Methanosarcina mazei, Methanosarcina thermophila, Methanomicrobium mobile, Methanocaldococcus jannaschii, Methanococcus aeolicus, Methanococcus maripaludis, Methanococcus vannielii, Methanococcus voltaei, Methanothermococcus thermolithotrophicus, Methanopyrus kandleri, Methanothermobacter thermoautotroiphicus, Methanocaldococcus fervens, Methanocaldococcus indicus, Methanocaldococcus infernus , and  Methanocaldococcus vulcanius.    
     
     
         28 . A cascaded bioreactor comprising:
 a first reactor vessel   a second reactor vessel   a culture of hydrogenotrophic methanogenic archaea which is present in the first and second reactor vessels;   a source of an output gas from an industrial process comprising CO2 that feeds into the first reactor vessel;   a source of hydrogen gas that feeds into the first reactor vessel;   a gas feed from the first reactor vessel to the second reactor vessel;   a feed to the first reactor vessel for providing fresh medium;   a feed to the second reactor vessel for providing fresh medium;   a feed to the first reactor vessel for removing the hydrogenotrophic methanogenic archaea culture; and   a feed to the second reactor vessel for removing the hydrogenotrophic methanogenic archaea culture.   
     
     
         29 . The cascaded bioreactor of  claim 28  further comprising:
 a third reactor vessel; 
 a culture of hydrogenotrophic methanogenic archaea which is present in the third reactor vessel; 
 a gas feed from the second reactor vessel to the third reactor vessel; 
 a feed to the third reactor vessel for providing fresh medium; and 
 a feed to the third reactor vessel for removing the hydrogenotrophic methanogenic archaea culture.