Process for removing harmful substances from liquid carbon dioxide and apparatus for the performance thereof

Abstract

A process for removing harmful substances from a gas steam which includes carbon dioxide and substances of value, such as at least one of the gases hydrogen H 2 carbon monoxide CO, nitrogen N 2 or noble gases, and harmful substances such as a substance from the group of mercury, sulphur, mercury compounds or sulphur compounds, wherein a carbon dioxide condensation is performed in order to obtain liquid carbon dioxide, adsorptive removal of the harmful substances from the condensed carbon dioxide is performed to remove the harmful substances from the carbon dioxide. A process temperature of less than −30° C. but great than −70° C. is maintained.

1 - 8 . (canceled) 
     
     
         9 . A process for separating a harmful substance from a gas mixture which essentially consists of carbon dioxide as well as a recyclable substance, comprising:
 carrying out a carbon dioxide condensation in order to produce and to separate liquid carbon dioxide;   carrying out an adsorptive separation of the harmful substance from the liquid carbon dioxide in order to remove the harmful substance from the liquid carbon dioxide; and   setting a process temperature in a range from −30° C. to −70° C.   
     
     
         10 . The process as claimed in  claim 9 , wherein the recyclable substance contained in the gas mixture is selected from the group consisting of hydrogen, carbon monoxide, nitrogen, and a noble gas. 
     
     
         11 . The process as claimed in  claim 9 , wherein the harmful substance contained in the gas mixture is selected from the group consisting of sulfur, mercury, sulfur compounds and mercury compounds. 
     
     
         12 . The process as claimed in  claim 9 , wherein that at least one substance from a group of substances comprising activated carbon, zeolite, silica gel, alumina or at least one polymer having a large surface area is selected as an adsorbent for the adsorptive separation of the harmful substance. 
     
     
         13 . The process as claimed in  claim 9 , wherein the separation of at least one harmful substance from cryogenic carbon dioxide takes place in low- or zero-carbon dioxide power stations. 
     
     
         14 . An apparatus for separating a harmful substance from a gas mixture which essentially consists of carbon dioxide as well as a recyclable substance, comprising:
 a carbon dioxide condensation unit for producing liquid carbon dioxide; and   a fixed-bed adsorber for the adsorptive separation of the harmful substance from liquid carbon dioxide for the purpose of removing the harmful substances therefrom, and   wherein the operating temperature of the apparatus lies in a range from −70° C. to −30° C.   
     
     
         15 . The apparatus as claimed in  claim 14 , wherein for the purpose of the adsorptive separation, the fixed-bed adsorber includes at least one adsorbent selected from the group consisting of activated carbon, zeolite, alumina and a polymer having a large surface area. 
     
     
         16 . The apparatus as claimed in  claim 14 ,
 wherein a plurality of fixed-bed adsorbers are present, and   wherein the plurality of fixed-bed adsorbers may be connected in parallel in groups, such that adsorbers or groups of adsorbers may be switched over to allow regeneration of the adsorbents.   
     
     
         17 . The apparatus as claimed in  claim 14 , wherein the recyclable substance is selected from the group consisting of hydrogen, carbon monoxide, nitrogen, and a noble gas. 
     
     
         18 . The apparatus as claimed in  claim 14 , wherein the harmful substance is selected from the group consisting of mercury, sulfur, and compounds thereof.