Process and device for treating flue gases

Abstract

A process and a device for treating a carbon dioxide-containing flue gas stream are described. At least a part of the carbon dioxide present is removed from the flue gas stream by means of a scrubber, forming a low carbon dioxide gas stream and a high carbon dioxide gas stream. The high carbon dioxide and water-saturated gas stream formed from the flue gas stream after removal of the carbon dioxide is cooled by means of a refrigeration system 4 in a heat exchanger 3 below the dew point temperature of the water contained in the gas stream and dried by condensing and separating out the water in a condensate separator 5 . The dried gas stream meets the requirements of carbon dioxide products intended for further use.

1 . Process for treating a carbon dioxide-containing flue gas stream, wherein at least a part of the carbon dioxide present is removed from the flue gas stream by means of a scrubber, forming a low carbon dioxide gas stream and a high carbon dioxide gas stream, characterized in that the high carbon dioxide and water-saturated gas stream formed from the flue gas stream after removal of the carbon dioxide is cooled by means of a refrigeration system ( 4 ) below the dew point temperature of the water contained in the gas stream and dried by condensing and separating out the water. 
     
     
         2 . Process according to  claim 1 , characterized in that, as a refrigeration system ( 4 ), an absorption refrigeration system is used. 
     
     
         3 . Process according to  claim 2 , characterized in that the absorption refrigeration system is driven by means of thermal energy, in particular in the form of steam and/or remote heat and/or direct firing. 
     
     
         4 . Process according to  claim 3 , characterized in that, in the case of treatment of a flue gas stream from a coal-fired combustion and/or gasification plant, the thermal energy is obtained from vapours (BD) and/or vapour condensate of a coal drying stage connected upstream of the combustion and/or gasification plant. 
     
     
         5 . Process according to  claim 1 , characterized in that the high carbon dioxide gas stream is dried to a water content of less than 500 ppmv, wherein a glycol-water mixture is sprayed in for avoiding gas hydrate formation. 
     
     
         6 . Process according to  claim 1 , characterized in that the high carbon dioxide gas stream is dried at a pressure between 30 and 60 bara, preferably between 35 and 40 bara. 
     
     
         7 . Process according to  claim 1 , characterized in that the high carbon dioxide gas stream is formed in a regeneration of a scrubbing medium used for scrubbing, which scrubbing medium contains as a component at least one amine. 
     
     
         8 . Process according to  claim 1 , characterized in that the dried, high carbon dioxide gas stream is fed to a utilization or storage. 
     
     
         9 . Device for treating a carbon dioxide-containing flue gas stream having a scrubbing appliance for scrubbing out from the flue gas stream at least a part of the carbon dioxide present, forming a low carbon dioxide gas stream and a high carbon dioxide gas stream, characterized in that a refrigeration system ( 4 ) for cooling and drying the high carbon dioxide gas stream is connected downstream of the scrubbing appliance. 
     
     
         10 . Device according to  claim 9 , characterized in that the refrigeration system ( 4 ) is constructed as an absorption refrigeration system.