Process and device for feeding oxidizing agent into a combustion system

Abstract

A process and device for feeding oxygen-containing gas into the firebox of a combustion system is disclosed. A sub-quantity of the flue gas stream exiting from the combustion system (recycle gas) is subjected to pressure elevation and subsequently recycled to the firebox. An oxygen-containing gas which is present at a sufficiently high pressure is added to the recycle gas downstream of the pressure elevation.

1 . A process for feeding oxygen-containing gas into a firebox of a combustion system, a sub-quantity of a flue gas stream exiting from the combustion system as a recycle gas is subjected to a pressure elevation and subsequently recycled to the firebox, wherein an oxygen-containing gas which is present at a sufficiently high pressure is added to the recycle gas downstream of the pressure elevation.  
   
   
       2 . The process according to  claim 1 , wherein the oxygen-containing gas is air and/or oxygen and/or nitrogen-enriched oxygen.  
   
   
       3 . The process according to  claim 2 , wherein the oxygen or nitrogen-enriched oxygen is obtained from an air fractionation system.  
   
   
       4 . The process according to  claim 1 , wherein the recycle gas is cleaned flue gas.  
   
   
       5 . The process according to  claim 1 , wherein the oxygen-containing gas is fed into the firebox of a steam generator of a thermal power station.  
   
   
       6 . A device for feeding oxygen-containing gas into a firebox of a combustion system, wherein a sub-quantity of a flue gas stream exiting from the combustion system as a recycle gas is subjected to a pressure elevation and subsequently recycled to the firebox, wherein an oxygen-containing gas which is present at a sufficiently high pressure is fed via a mixing system to the recycle gas downstream of the pressure elevation.  
   
   
       7 . The device according to  claim 6 , wherein in an immediate vicinity of the combustion system, an air fractionation system is provided from which the oxygen-containing gas which is oxygen or nitrogen-enriched oxygen is obtained at the sufficiently high pressure.  
   
   
       8 . The device according to  claim 7 , wherein the air fractionation system is a cryogenic air fractionator or a pressure-swing adsorption system (PSA).  
   
   
       9 . The device according to  claim 6 , wherein the combustion system is a steam generator of a thermal power station.  
   
   
       10 . A method for feeding an oxygen-containing gas into a firebox of a combustion system, comprising the steps of: 
 removing a quantity of a flue gas exiting from the combustion system;    adding air to the quantity of the flue gas to form an air/flue gas stream;    compressing the air/flue gas stream;    adding a gas containing oxygen to the air/flue gas stream to form the oxygen-containing gas; and    supplying the oxygen-containing gas to the firebox.    
   
   
       11 . The method according to  claim 10 , wherein the air/flue gas stream is compressed from a pressure which is lower than an atmospheric pressure to a pressure that is higher than the atmospheric pressure.  
   
   
       12 . The method according to  claim 10 , further comprising the step of removing ash and water from the flue gas exiting from the combustion system prior to the step of removing the quantity of the flue gas.  
   
   
       13 . An apparatus for feeding an oxygen-containing gas into a firebox of a combustion system, comprising: 
 a recycle line, wherein a quantity of a flue gas exiting from the combustion system is removed;    an air supply line coupled to the recycle line, wherein air is added to the quantity of the flue gas by the air supply line to form an air/flue gas stream;    a compressor, wherein the compressor compresses the air/flue gas stream;    an oxygen containing gas supply line, wherein the oxygen containing gas supply line adds a gas containing oxygen to the compressed air/flue gas stream to form the oxygen-containing gas; and    an oxygen-containing gas supply line, wherein the oxygen-containing gas supply line supplies the oxygen-containing gas to the firebox.    
   
   
       14 . The apparatus according to  claim 13 , wherein the oxygen-containing gas supply line is coupled to an air fractionator.  
   
   
       15 . The apparatus according to  claim 13 , further comprising a flue gas cleaning system coupled to the firebox in a downstream flow direction of the flue gas.  
   
   
       16 . The apparatus according to  claim 15 , wherein the flue gas cleaning system removes ash and water from the flue gas.  
   
   
       17 . The apparatus according to  claim 16 , wherein the recycle line is disposed in the downstream flow direction from the flue gas cleaning system.  
   
   
       18 . The apparatus according to  claim 13 , wherein the compressor compresses the air/flue gas stream from a pressure which is lower than an atmospheric pressure to a pressure that is higher than the atmospheric pressure.