Method of cleaning a carbon dioxide rich flue gas and a boiler system

Abstract

A boiler system for combusting a fuel in the presence of a gas containing oxygen gas, and a gas cleaning system. The boiler system includes a compression device, a carbon dioxide supply duct operative for forwarding at least a portion of the pressurized carbon dioxide rich flue gas to at least one gas cleaning device.

1 . A method of cleaning a carbon dioxide rich flue gas generated in a boiler combusting a fuel in the presence of a gas containing oxygen gas, the method comprising:
 forwarding the carbon dioxide rich flue gas from the boiler to a gas cleaning system;   removing in said gas cleaning system at least a portion of the contaminant content of the carbon dioxide rich flue gas;   forwarding a first portion of the carbon dioxide rich flue gas from which at least a portion of the contaminant content has been removed to a gas compression and purification unit;   forwarding a part of the first portion from the gas compression and purification unit to at least one gas cleaning device for being utilized as a utility gas therein;   pressurizing a second portion of the carbon dioxide rich flue gas from which at least a portion of the contaminant content has been removed upstream of the gas compression and purification unit; and   forwarding the second portion of the carbon dioxide rich flue gas to the at least one gas cleaning device for being utilized as a utility gas therein.   
     
     
         2 . The method according to  claim 1 , further comprising:
 forwarding the second portion of the carbon dioxide rich flue gas to a fabric filter for being used as a utility gas therein;   and forwarding the second portion of the carbon dioxide rich flue gas to a mixing device for being used as a utility gas therein.   
     
     
         3 . The method according to  claim 2 , wherein the second portion of the carbon dioxide rich flue gas is collected downstream of a filter removing particulate material supplied to said contact reactor by said mixing device. 
     
     
         4 . The method according to  claim 1 , wherein the second portion of the carbon dioxide rich flue gas is forwarded to a tank for being temporary stored, prior to being utilized as a utility in the gas cleaning device. 
     
     
         5 . A boiler system comprising
 a boiler for combusting a fuel in the presence of a gas containing oxygen gas;   a gas cleaning system configured to remove at least a portion of the contaminant content of the carbon dioxide rich flue gas generated in the boiler;   a gas compression and purification unit;   ducting configured to forward a first portion of the carbon dioxide rich flue gas from which at least a portion of the contaminant content has been removed to the gas compression and purification unit and ducting for forwarding a part of the first portion from the gas compression and purification unit to at least one gas cleaning device for being utilized as a utility gas therein;   a compression device configured to pressurize a second portion of the carbon dioxide rich flue gas from which at least a portion of the contaminant content has been remove; and   a carbon dioxide supply duct departing upstream of the gas compression and purification unit and operative for forwarding the second portion of the carbon dioxide rich flue gas to the at least one gas cleaning device for being utilized as a utility gas therein.   
     
     
         6 . The boiler system according to  claim 5 , wherein the at least one gas cleaning device forms part of the gas cleaning system. 
     
     
         7 . The boiler system according to  claim 5 , wherein the at least one gas cleaning device comprises a fabric filter and a mixing device configured to supply particulate material mixed with absorbent to a contact reactor being operative for bringing the particulate material mixed with absorbent into contact with a flue gas, the carbon dioxide supply duct being operative for forwarding the second portion of the carbon dioxide rich flue gas to the fabric filter and to the mixing device for fluidisation. 
     
     
         8 . The boiler system according to  claim 5 , wherein the compression device comprises a blower. 
     
     
         9 . A method of cleaning a carbon dioxide rich flue gas generated in a boiler combusting a fuel in the presence of a gas containing oxygen gas, the method comprising:
 forwarding the carbon dioxide rich flue gas from the boiler to a gas cleaning system, removing in said gas cleaning system at least a portion of a contaminant content of the carbon dioxide rich flue gas being forwarded from the boiler,   pressurizing at least a portion of the carbon dioxide rich flue gas from which at least the portion of the contaminant content has been removed, wherein said pressurizing is conducted in a gas compression and purification unit operating to prepare a pressurized carbon dioxide gas for disposal from the carbon dioxide rich flue gas that has been cleaned in the gas cleaning system, the gas compression and purification unit comprising a low pressure compression unit operative for increasing the pressure of the carbon dioxide rich flue gas to a pressure of 20 to 50 bar absolute pressure; and   forwarding at least a portion of the pressurized portion of the carbon dioxide rich flue gas from which at least the portion of the contaminant content has been removed to at least one gas cleaning device for being utilized as a utility gas therein, said forwarding at least the portion of the pressurized portion of the carbon dioxide rich flue gas comprising forwarding the portion of the carbon dioxide rich flue gas that has passed through at least a part of the low pressure compression unit to said at least one gas cleaning device.   
     
     
         10 . A boiler system comprising:
 a boiler for combusting a fuel in the presence of a gas containing oxygen gas, a gas cleaning system being operative for removing at least a portion of a contaminant content of the carbon dioxide rich flue gas generated in the boiler;   a compression device configured to pressureize at least a portion of the carbon dioxide rich flue gas from which at least the portion of the contaminant content has been removed; and   a carbon dioxide supply duct being operative for forwarding at least a portion of the pressurized portion of the carbon dioxide rich flue gas from which at least the portion of the contaminant content has been removed to at least one gas cleaning device for being utilized as a utility gas therein;   a gas compression and purification unit operative for preparing a pressurized carbon dioxide gas for disposal from the carbon dioxide rich flue gas that has been cleaned in the gas cleaning system, said compression device being included in the gas compression and purification unit, said carbon dioxide supply duct being operative for forwarding at least the portion of said pressurized portion of the carbon dioxide rich flue gas from which at least the portion of the contaminant content has been removed from the gas compression and purification unit to said at least one gas cleaning device; and wherein   the gas compression and purification unit comprise a low pressure compression unit operative for increasing the pressure of the carbon dioxide rich flue gas to a pressure of 20 to 50 bar absolute pressure, the carbon dioxide supply duct being operative for forwarding a portion of the carbon dioxide rich flue gas that has passed through at least a part of the low pressure compression unit to said at least one gas cleaning device.   
     
     
         11 . A method of cleaning a carbon dioxide rich flue gas generated in a boiler combusting a fuel in the presence of a gas containing oxygen gas, the method comprising:
 forwarding the carbon dioxide rich flue gas from the boiler to a gas cleaning system,   removing in said gas cleaning system at least a portion of a contaminant content of the carbon dioxide rich flue gas being forwarded from the boiler,   forwarding a first portion of the carbon dioxide rich flue gas from which at least the portion of the contaminant content has been removed to a gas compression and purification unit,   pressurizing at least a second portion of the carbon dioxide rich flue gas from which at least the portion of the contaminant content has been removed upstream of the gas compression and purification unit, and   forwarding the pressurized second portion of the carbon dioxide rich flue gas from which at least the portion of the contaminant content has been removed to at least one gas cleaning device for being utilized as a utility gas therein.   
     
     
         12 . A boiler system comprising:
 a boiler for combusting a fuel in the presence of a gas containing oxygen gas, a gas cleaning system being operative for removing at least a portion of a contaminant content of a carbon dioxide rich flue gas generated in the boiler;   a gas compression and purification unit,   ducting for forwarding a first portion of the carbon dioxide rich flue gas from which at least the portion of the contaminant content has been removed to the gas compression and purification unit, and   a compression device being operative for pressurizing a second portion of the carbon dioxide rich flue gas from which at least the portion of the contaminant content has been removed, and   a carbon dioxide supply duct positioned upstream of the gas compression and purification unit and operative for forwarding the pressurized second portion of the carbon dioxide rich flue gas from the compression device to at least one gas cleaning device for being utilized as a utility gas therein.