Method and system for capturing carbon dioxide in an oxyfiring process where oxygen is supplied by regenerable metal oxide sorbents

Abstract

An oxyfiring system is disclosed. The oxyfiring system comprises (a) an oxidation reactor for oxidizing a reduced metal oxide; (b) a decomposition reactor wherein a decomposition fuel is combusted and oxidized metal oxide sorbents are reduced with oxygen being released and a flue gas with an oxygen enriched carbon dioxide stream is produced; (c) a fuel combustion reactor for combusting a primary fuel and the oxygen enriched carbon dioxide stream into a primary flue gas; and (d) separation apparatus for separating a portion of the primary flue gas so that a carbon dioxide enriched stream can be prepared.

What is claimed is: 
     
         1 . An oxyfiring system for capturing carbon dioxide in a combustion process, the oxyfiring system comprising:
 (a) a combustion reactor for combusting a primary fuel with an oxygen enriched carbon dioxide stream to create a primary flue gas stream including carbon dioxide and water vapor;   (b) an oxidation reactor utilizing air to re-oxidize a reduced metal oxide sorbent to an oxidized metal oxide sorbent;   (c) a decomposition reactor in communication with the oxidation reactor to receive oxidized metal oxide sorbents and to return to the oxidation reactor reduced metal oxide sorbents and in communication with the combustion reactor to receive a portion of the primary flue gas there from and to deliver an oxygen enhanced carbon dioxide stream to the primary combustion reactor; and   (d) a separation apparatus for separating carbon dioxide from a portion of the primary flue gas stream received from the combustion reactor;
 where in the decomposition reactor the oxidized metal oxide sorbent may release oxygen to produce a reduced metal oxide sorbent with the oxygen partially combusting with a decomposition fuel and partially enriching the portion of the primary flue gas stream received from the combustion reactor to produce an oxygen enriched carbon dioxide stream which is delivered to the combustion reactor to provide a source of oxygen for combustion. 
   
     
     
         2 . The oxyfiring system of  claim 1  wherein:
 the combustion reactor is one of a fluid catalyst cracker catalyst regenerator, a boiler, a fired heater, a power plant steam generator, biomass pyrolysis char combustor and a gas-fired turbine. 
 
     
     
         3 . The oxyfiring system of  claim 1  wherein:
 the oxidized metal oxide sorbent is selected from the group consisting of one or more of a copper oxide (CuO), manganese oxide (Mn 2 O 3 ) or cobalt oxide (Co 3 O 4 ) carried on a substrate. 
 
     
     
         4 . The oxyfiring system of  claim 3  wherein:
 the metal oxide sorbent has a substrate is selected from the group of consisting of one or more of alumina, silica, aluminosilica, titania, and zirconia. 
 
     
     
         5 . A method for retrofitting a combustion system comprising:
 replacing air used as a source of oxygen to combust with a primary fuel in a combustion reactor with an oxygen enriched carbon dioxide stream;   wherein the oxygen enriched carbon dioxide stream is supplied from a decomposition reactor wherein oxidized metal oxide sorbents are decomposed to reduced metal oxide sorbents to produce oxygen which enriches a carbon dioxide stream to produce the oxygen enriched carbon dioxide stream supplied to the combustion reactor.   
     
     
         6 . The method of  claim 5  wherein:
 the reduced metal oxide sorbents are recycled to an air reactor wherein air reacts with the reduced metal oxide sorbents to produce the oxidized metal oxide sorbents supplied to the decomposition reactor and a stream of air depleted in oxygen. 
 
     
     
         7 . The method of  claim 5  wherein:
 the carbon dioxide stream which is enriched with oxygen in the decomposition reactor is received from the combustion reactor.