Carbon removal from an integrated thermal recovery process

Abstract

The present invention is directed to the recovery of hydrocarbons wherein a portion of carbon is removed from the product by a combination of reforming and water-gas shift. The resulting carbon dioxide is removed by known techniques to provide a fuel having reduced levels of carbon.

1 .- 8 . (canceled) 
     
     
         9 . A system, comprising:
 an input to receive a gas stream comprising primarily methane;   a gas separator to remove a first portion of the gas stream from a second portion of the gas stream;   a steam methane reformer reactor to convert the first portion of the gas stream to a reformed gas comprising primarily molecular hydrogen and carbon monoxide;   a water-gas shift reactor to convert the reformed gas into a reformed and water-gas shifted gas comprising primarily carbon dioxide and molecular hydrogen;   a carbon separator to remove, from the reformed and water-gas shifted gas, at least most of the carbon dioxide to form a product gas; and   a gas combiner to combine the product gas with the second portion of the gas stream to form a mixed gas, whereby a carbon content of the mixed gas is reduced relative to the received gas stream;   wherein the carbon separator performs at least the following operations:
 contact the reformed and water-gas shifted with an alkali and/or an alkaline earth metal oxide to form alkali and/or an alkaline earth metal carbonates and molecular hydrogen; 
 remove, from the reformed and water-gas shifted gas, at least most of the alkali and/or an alkaline earth metal carbonates to form the product gas comprising at least most of the molecular hydrogen and substantially free of carbon dioxide; 
 pass the alkali and/or an alkaline earth metal carbonates through a heat exchanger in fluid communication with the water-gas shift reactor, to reform the alkali and/or an alkaline earth metal oxide and carbon dioxide, the carbon dioxide being substantially free of molecular hydrogen. 
   
     
     
         10 . The system of  claim 9 , wherein the gas stream is pipeline quality natural gas, wherein the second gas stream is combusted by a turbine to generate electricity, and wherein the removed carbon dioxide is utilized to avoid releasing carbon dioxide into the atmosphere. 
     
     
         11 . The system of  claim 10 , wherein the steam methane reformer reactor heats the first portion of the gas stream to a temperature ranging from about 850° C. to about 1100° C., wherein the water-gas shift reactor comprises at least one of a high temperature water-gas shift reactor and a low temperature water-gas shift reactor, and wherein the reformed gas comprises from about 25 to about 95 mole percent molecular hydrogen and from about 5 to about 25 mole percent carbon monoxide. 
     
     
         12 . The system of  claim 9 , wherein water is heated to a temperature of from about 50° C. to about 300° C. by energy released by the water-gas shift reactor and wherein the heated water is used as the steam in the water-gas shift reactor. 
     
     
         13 . The system of  claim 9 , further comprising:
 a combustion gas turbine operated by at least a portion of the mixed gas stream to produce electrical energy.   
     
     
         14 . (canceled) 
     
     
         15 . The system of  claim 9 , wherein at least a portion of the product gas is passed through a heat exchanger to transfer, to the at least a portion of the product gas, heat from the water-gas shift reaction, wherein the heated at least a portion of the product gas is fed to the reformer to form the synthetic gas. 
     
     
         16 . The system of  claim 9 , wherein the mixed gas comprises no more than about 80% of the carbon present in the received gas stream. 
     
     
         17 .- 21 . (canceled)