CO2 Recovery Method Using Cryo-Condensation

Abstract

The present invention relates to a method of capturing carbon dioxide in a fluid comprising at least one compound more volatile than carbon dioxide CO2, for example methane CH4, oxygen O2, argon Ar, nitrogen N2, carbon monoxide CO, helium He and/or hydrogen H2.

1 - 15 . (canceled) 
     
     
         16 . A method for producing at least one CO2-lean gas and one or more CO2-rich primary fluids from a process fluid containing CO2 and at least one compound more volatile than CO2 comprising:
 a) a first cooling of said process fluid by exchange of heat with no change in state;   b) a second cooling of at least part of said process fluid cooled in step a) so as to obtain at least one solid containing predominantly CO2 and at least said CO2-lean gas; and   c) the liquefaction and/or sublimation of at least part of said solid and making it possible to obtain said one or more CO2-rich primary fluids;   wherein at least part of the cold required to perform said first cooling and/or said second cooling is supplied by one or more refrigerating cycles each comprising at least one near-isentropic expansion of a gas.   
     
     
         17 . The method of  claim 16 , wherein said refrigerating cycles each comprising at least one near-isentropic expansion employ working fluids chosen from the following:
 an auxiliary fluid containing nitrogen and/or argon and/or a mixture of air gases;   a fluid comprising all or some of said CO2-lean gas) or derived from all or part of said CO2-lean gas; and/or   a fluid comprising all or part of said process fluid or derived from all or part of said process fluid.   
     
     
         18 . The method of  claim 16 , wherein at least part of the cold required for performing said second cooling is supplied by exchange with:
   the working fluid of one of said refrigerating cycles each comprising at least one near-isentropic expansion;   an auxiliary fluid containing nitrogen and/or argon and/or a mixture of air gases;   a fluid containing all or part of said CO2-lean gas or derived from all or part of said CO2-lean gas; and/or   a fluid containing all or part of said process fluid or derived from all or part of said process fluid.     
     
     
         19 . The method of  claim 18 , wherein at least part of the cold needed to carry out said second cooling is supplied by direct exchange. 
     
     
         20 . The method of  claim 17 , wherein at least one of said refrigerating cycles each comprising at least one near-isentropic expansion employs all or part of said process fluid as working fluid. 
     
     
         21 . The method of  claim 16 , wherein at least one of said refrigerating cycles each comprising at least one near-isentropic expansion comprises at least one near-isentropic expansion supplying external work. 
     
     
         22 . The method of  claim 21 , further comprising a step d) of heating up at least one of said CO2-rich primary fluids and/or said CO2-lean gas by cold compression and/or by exchange of heat with an auxiliary fluid. 
     
     
         23 . The method of  claim 20 , wherein said near-isentropic expansion of at least one of said refrigerating cycles each comprising at least one near-isentropic expansion comprises one or more of the following steps:
 causing the process fluid to rotate about an axis substantially parallel to the direction of flow of said process;   raising the speed of the process fluid;   separating the solid CO2 from the process fluid using a centrifugal effect;   decelerating the gas that has become CO2-lean.   
     
     
         24 . The method of  claim 16 , wherein, in step b), at least part of said process fluid cooled in step a) is cooled in such a way as further to obtain a liquid comprising predominantly CO2. 
     
     
         25 . The method of  claim 16 , wherein said process fluid comes from industrial flue gases. 
     
     
         26 . The method of  claim 16 , wherein said process fluid comes from a steel-making plant. 
     
     
         27 . The method of  claim 26 , wherein:
 said process fluid comes at least partially from a blast furnace; and   said CO2-lean gas is at least partially recirculated into said blast furnace.   
     
     
         28 . The method of  claim 16 , wherein said process fluid comes at least partially from a refinery and/or from a chemical plant. 
     
     
         29 . The method of  claim 28 , wherein said process fluid comes at least partially from the gasification and/or the partial oxidation and/or an oxygen reforming of a given carbon fuel. 
     
     
         30 . The method of  claim 26 , wherein:
 said process fluid comes from a plant comprising an air separation unit; and   said near-isentropic expansion of at least one of said refrigerating cycles each comprising at least one near-isentropic expansion of a gas is carried out in said air separation unit.