Methanation and Recovery Method, System, and Apparatus

Abstract

A method, a system, and an apparatus of certain embodiments are provided to recover water and carbon dioxide from combustion emissions. The recovery includes, among other things, electrolysis and carbon dioxide capture in a suitable solvent. The recovered water and carbon dioxide are subject to reaction, such as a catalytic methanation reaction, to generate at least methane.

What is claimed is: 
     
         1 . A system comprising:
 a chamber configured to contain liquid water and to receive a hydrocarbon combustion exhaust stream comprising water and carbon dioxide;   a heat exchanger positioned in the first chamber and configured to convey methanation reaction products through the chamber to transfer heat from the methanation reaction products to the liquid water; and   an electrolysis system configured to subject the heated liquid water to electrolysis to generate hydrogen and oxygen, the electrolysis system comprising an anode and a cathode each received in the chamber.   
     
     
         2 . The system of  claim 1 , further comprising:
 a second heat exchanger positioned in the chamber configured to heat solvent and carbon dioxide captured in the solvent, wherein the first and second heat exchangers comprise a common heat exchanger or different heat exchangers; and   a separator configured to separate at least a portion of the carbon dioxide from the heated solvent.   
     
     
         3 . The system of  claim 2 , further comprising:
 a carbon dioxide absorber configured to capture the carbon dioxide in the solvent; and   a carbon dioxide desorber configured to separate the at least a portion of the carbon dioxide from the heated solvent.   
     
     
         4 . The system of  claim 3 , wherein:
 the carbon dioxide desorber is configured to discharge a first stream comprising the carbon dioxide and a different second stream comprising the heated solvent; and   the carbon dioxide desorber is configured to cool the first and second streams.   
     
     
         5 . The system of  claim 3 , wherein the carbon dioxide absorber is positioned substantially concentrically outside of the carbon dioxide desorber. 
     
     
         6 . The system of  claim 2 , further comprising a methanation reactor configured to react at least the hydrogen generated by the electrolysis and the carbon dioxide separated from the heated solvent to generate the methanation reaction products. 
     
     
         7 . The system of  claim 6 , further comprising:
 a thermal mass configured to be heated with heat generated by the reacting of at least the hydrogen and the carbon dioxide in the methanation reactor; and   a preheater configured to preheat the hydrogen generated by the electrolysis and the carbon dioxide separated from the heated solvent, the preheater being further configured to be heated with the thermal mass.   
     
     
         8 . The system of  claim 7 , wherein the methanation pre-heater is positioned substantially concentrically within the methanation reactor. 
     
     
         9 . The system of  claim 7 , further comprising:
 a carbon dioxide absorber configured to capture the carbon dioxide in a solvent; and   a desorber configured to separate at least a portion of the carbon dioxide from the heated solvent.   
     
     
         10 . The system of  claim 9 , wherein:
 the methanation reactor is positioned substantially concentrically outside of the methanation pre-heater;   the first chamber is positioned substantially concentrically outside of the methanation pre-heater;   the carbon dioxide desorber is positioned substantially concentrically outside of the first chamber; and   the carbon dioxide absorber is positioned substantially concentrically outside of the carbon dioxide desorber.   
     
     
         11 . The system of  claim 1 , further comprising a second chamber that is different than the first chamber, the second chamber being configured to separate methane from the water of the methanation reaction products. 
     
     
         12 . The system of  claim 11 , wherein the first chamber and the second chamber are contained in a common tank. 
     
     
         13 . The system of  claim 12 , wherein the second chamber is positioned substantially concentrically outside of the first chamber. 
     
     
         14 . The system of  claim 1 , wherein the first chamber is configured to condense at least a portion of gaseous water in the hydrocarbon combustion exhaust stream to add to the liquid water in the first chamber. 
     
     
         15 . A system comprising:
 a chamber configured to subject liquid water to electrolysis to generate hydrogen and oxygen;   a carbon dioxide absorber configured to capture carbon dioxide in a solvent;   a first heat exchanger positioned in the chamber and configured to convey the solvent and the captured carbon dioxide through the chamber; and   a second heat exchanger positioned in the chamber and configured to convey methanation reaction products through the chamber to transfer heat from the methanation reaction products to the liquid water in the chamber and to the solvent conveyed through the first heat exchanger of the chamber, wherein the first and second heat exchangers comprise a common heat exchanger or different heat exchangers.   
     
     
         16 . The system of  claim 15 , further comprising:
 a carbon dioxide desorber configured to separate at least a portion of the carbon dioxide from the heated solvent.   
     
     
         17 . The system of  claim 16 , wherein the carbon dioxide desorber is positioned substantially concentrically outside of the first chamber, and wherein the carbon dioxide absorber is positioned substantially concentrically outside of the carbon dioxide desorber. 
     
     
         18 . The system of  claim 15 , wherein the chamber comprises a first chamber, and wherein the system further comprises a different second chamber configured to separate methane from water of the methanation reaction products. 
     
     
         19 . The system of  claim 18 , wherein the second chamber is positioned substantially concentrically outside of the first chamber. 
     
     
         20 . A system comprising:
 a chamber configured to contain liquid water and to receive a hydrocarbon combustion exhaust stream comprising water and carbon dioxide;   a first heat exchanger positioned in the chamber and configured to convey methanation reaction products through the chamber to transfer heat from the methanation reaction products to the liquid water;   an electrolysis system comprising an anode and a cathode positioned in the chamber, electrolysis system configured to generate hydrogen and oxygen from the heated liquid water;   a carbon dioxide absorber configured to capture the carbon dioxide in a solvent;   a second heat exchanger positioned in the first chamber and configured to heat the solvent and the captured carbon dioxide with thermal energy from the methanation reaction products, wherein the first and second heat exchangers comprise a common heat exchanger or different heat exchangers;   a carbon dioxide desorber configured to separate at least a portion of the carbon dioxide from the heated solvent; and   a methanation reactor configured to react at least the hydrogen generated by the electrolysis system and the carbon dioxide separated from the heated solvent to generate one or more hydrocarbons.