Method and system for the separation of a mixture containing carbon dioxide, hydrocarbon and hydrogen

Abstract

The invention provides a method and system for the separation of a mixture containing H2, hydrocarbon, and C02. The generated mixture ( 3 ) is introduced into a distillation column ( 2 ) having a side stream to generate a top stream comprising H2 ( 21 ), a middle (volatility) stream comprising hydrocarbon ( 30 ); and a bottom stream comprising C02 ( 32 ). In a preferred embodiment, the mixture further comprises N2 which is obtained in the top stream ( 21 ). In a most preferred embodiment, the H2 and the N2 are present in a molar ratio of 3H2:1N2. The generated H2 and N2 may be used for the synthesis of ammonia. Thus, the invention also proves a method and system for the generation of ammonia.

1 . A method for the separation of a mixture containing H 2 , hydrocarbon, and CO 2 , the method comprising introducing the mixture into a distillation column having a side stream to generate:
 (i) a top stream comprising H 2 ;   (ii) a middle (volatility) stream comprising hydrocarbon; and   (iii) a bottom stream comprising CO 2 .   
   
   
       2 . The method according to  claim 1  wherein the mixture further comprises N 2  which is obtained by the method in the top stream. 
   
   
       3 . The method according to  claim 2  wherein the H 2  and the N 2  are present in a molar ratio of 3:1. 
   
   
       4 . The method according to  claim 1  or  3  wherein the hydrocarbon comprises methane. 
   
   
       5 . The method according to any one of  claims 1  to  4  wherein freezing of the CO 2  is substantially prevented. 
   
   
       6 . The method according to any one of the previous claims wherein the middle stream is obtained as a gas from a reboiler of the column. 
   
   
       7 . The method according to any one of  claims 1  to  6  wherein the middle stream is obtained from a tray of the column. 
   
   
       8 . The method according to any one of the previous claims where in the mixture is introduced into a reboiler of the column. 
   
   
       9 . The method according to any one of  claims 1  to  7  where in the mixture is introduced into a tray of the column. 
   
   
       10 . The method according to any one of the previous claims wherein reflux of the top stream to the column is performed using a reflux ratio between 0.001 and 10. 
   
   
       11 . The method according to  claim 10  wherein reflux of the top stream to the columns is performed using a reflux ratio between 0.05 and 2. 
   
   
       12 . The method according to any one of the previous claims wherein the column has a pressure between 5 bar to a critical pressure of the mixture. 
   
   
       13 . The method according to  claim 12  wherein the column has a pressure between 7 bar to 55 bar. 
   
   
       14 . The method according to any one of the previous claims further comprising cooling the mixture prior to introducing the mixture to the column. 
   
   
       15 . The method according to  claim 14  further comprising introducing the cooled mixture into a flush to remove CO 2  prior to introducing the stream into the column. 
   
   
       16 . The method according to  claim 15  wherein the cooled mixture is introduced into a reboiler of the column. 
   
   
       17 . A system for generating and separating a mixture containing H 2 , hydrocarbon, and CO 2 , the system comprising:
 (a) means for generating a mixture containing H 2 , hydrocarbon, and CO 2 ; and   (b) a distillation column having a side stream configured to receive the mixture and to generate from the mixture:
 (i) a top stream comprising H 2 ; 
 (ii) a middle stream comprising hydrocarbon; and 
 (iii) a bottom stream comprising CO 2 . 
   
   
   
       18 . The system according to  claim 17  wherein the means for generating the mixture further generates N 2  obtained in the top stream. 
   
   
       19 . The system according to  claim 18  wherein the means for generating the mixture generates a mixture containing H 2  and N 2  in a ratio of 3:1. 
   
   
       20 . The system according to  claim 17  or  19  wherein the hydrocarbon comprises methane. 
   
   
       21 . The system according to  claims 17  to  20  wherein freezing of the CO 2  is substantially prevented. 
   
   
       22 . The system according to any one of  claims 17  to  21  wherein the middle stream is obtained as a gas from a reboiler of the column. 
   
   
       23 . The system according to any one of  claims 17  to  21  wherein the middle stream is obtained from a tray of the column. 
   
   
       24 . The system according to any one of  claims 17  to  23  where in the mixture is introduced into a reboiler of the column. 
   
   
       25 . The system according to any one of  claims 17  to  23  wherein the mixture is introduced into a tray of the column. 
   
   
       26 . The system according to any one of  claims 17  to  25  wherein reflux of the top stream to the column is performed using a reflux ratio between 0.001 and 10. 
   
   
       27 . The system according to  claim 26  wherein reflux of the top stream to the columns is performed using a reflux ratio between 0.05 and 2. 
   
   
       28 . The system according to any one of  claims 17  to  27  wherein the column has a pressure between 5 bar to a critical pressure of the mixture. 
   
   
       29 . The system according to  claim 26  wherein the column has a pressure between 7 bar to 55 bar. 
   
   
       30 . The system according to any one of  claims 17  to  29  wherein the mixture is cooled prior to introducing the mixture to the column. 
   
   
       31 . The system according to  claim 30  wherein the cooled mixture is introduced into a flush to remove CO 2  prior to introducing the mixture into the column. 
   
   
       32 . The system according to  claim 30  wherein the cooled stream is introduced into a reboiler of the column. 
   
   
       33 . The system according to  claim 18  or  19  further comprising means for generating ammonia from the top stream. 
   
   
       34 . The method according to  claim 2  or  3  further comprising generating ammonia from the top stream. 
   
   
       35 . The method according to  claim 34  wherein the hydrocarbon is methane. 
   
   
       36 . The system according to  claim 33  wherein the hydrocarbon is methane.