Method for Removing and Recovering Co2 from an Exhaust Gas

Abstract

The present invention relates to a method for removing and recovering CO 2 from exhaust gas from a gas turbine based electric power and heat generation process (a main power process) by chemical absorption and desorption for deposition of CO 2 as convenient at the location. The exhaust gas from said main power process is cooled before being fed to a secondary gas turbine based power and heat generation process (a secondary power process) where said exhaust gas is compressed to elevated pressure and used as oxidant in a secondary gas turbine combustion chamber in said secondary power process. The resulting hot exhaust gas from said secondary process is further fed to a turbine connected to an electric power generator where the exhaust gas is depressurised to close to ambient pressure before entering a heat recovery process where the exhaust gas is cooled and further fed to a CO 2 separation process for capturing of CO 2 .

1 - 15 . (canceled)  
   
   
       16 . A method for capture of CO 2  from exhaust gas from a gas turbine based power and heat generation process (a main power process), wherein the exhaust gas from said main power process is cooled before being fed to a secondary gas turbine based power and heat generation process (a secondary power process) where said exhaust gas is compressed to elevated pressure and used as oxidant in a secondary gas turbine combustion chamber in said secondary power process, the resulting hot exhaust gas from said secondary process is further fed to a turbine connected to an electric power generator where the exhaust gas is depressurized to close to ambient pressure before entering a heat recovery process where the exhaust gas is cooled and further fed to a CO 2  separation process for capturing of CO 2 .  
   
   
       17 . A method according to  claim 16 , wherein the secondary power process and said CO 2  separation process is only connected with the main power process via the main power process exhaust gas duct.  
   
   
       18 . A method according to  claim 16 , wherein the exhaust gas from said main power process is cooled to below 100° C.  
   
   
       19 . A method according to  claim 16 , wherein the exhaust gas from the main power process is cooled to below 30° C.  
   
   
       20 . A method according to  claim 16 , wherein the exhaust gas from said main power process is compressed adiabatically to elevated pressure, preferably above 5 bar.  
   
   
       21 . A method according to  claim 16 , wherein the CO 2  containing exhaust gas is compressed without intercooling to between 5 and 40 bar in the secondary power plant.  
   
   
       22 . A method according to  claim 16 , wherein the temperature in said combustion chamber is above 850° C. or preferably above 1200° C.  
   
   
       23 . A method according to  claim 16 , wherein the depressurized exhaust gas is cooled to below 100° C.  
   
   
       24 . A method according to  claim 16 , wherein the exhaust gas from the secondary power plant is cooled to below 80° C.  
   
   
       25 . A method according to  claim 16 , wherein recovered heat is used to generate steam to be used to generate power in steam turbines and/or to heat a heating medium.  
   
   
       26 . A method according to  claim 16 , wherein the CO 2  separation process is an absorption and desorption process or any other process capable of separating CO 2  from exhaust gas.  
   
   
       27 . A method according to  claim 16 , wherein the heat needed in said CO 2  separation process is extracted from the secondary power process.  
   
   
       28 . A method according to  claim 16 , wherein 5-100% of the exhaust gas generated in the main power process is fed to the secondary power process.  
   
   
       29 . A method according to  claim 16 , wherein ambient air is mixed with the exhaust gas from the main power process before entering the secondary power process.  
   
   
       30 . A method according to  claim 16 , wherein the secondary power process is started up using ambient air.