Process for separating gases at cryogenic temperatures

Abstract

The invention relates to a process employing a multi-directional heat pump and a cryo-trap to separate gases. One embodiment relates to a process that includes heating a gaseous stream comprising carbon dioxide, hydrogen, and a push gas to produce a first intermediate stream comprising an amount of methane; contacting the first intermediate stream with a first trapping material to remove an amount of a component selected from the group consisting of oxygen, water, nitrogen, carbon dioxide, and combinations thereof from the first intermediate stream to produce a second intermediate stream; introducing the second intermediate stream to a separation zone comprising a surface of a second trapping material; employing a multi-directional heat pump to maintain the separation zone at a retaining temperature; retaining methane in the separation zone, while purging hydrogen from the separation zone; employing the multi-directional heat pump to adjust the separation zone to a releasing temperature; and releasing methane from the separation zone.

1 . A process comprising employing a multi-directional heat pump to maintain a separation zone at a retaining temperature; introducing a gaseous stream comprising a desired component and an undesired component to the separation zone; retaining an amount of the desired component in the separation zone, while purging an amount of the undesired component from the separation zone;
 employing the multi-directional heat pump to adjust the separation zone to a releasing temperature; and releasing the desired component from the separation zone, wherein the separation zone comprises a surface of a trapping material.   
     
     
         2 . The process of  claim 1 , wherein the desired component is radio-labeled methane ( 11 CH 4 ). 
     
     
         3 . The process of  claim 1 , wherein a push gas is employed to purge the amount of the undesired component from the separation zone. 
     
     
         4 . The process of  claim 3 , wherein the push gas comprises helium. 
     
     
         5 . The process of  claim 1 , wherein the gaseous stream further comprises hydrogen. 
     
     
         6 . The process of  claim 1 , wherein the gaseous stream further comprises the push gas. 
     
     
         7 . The process of  claim 1 , wherein the retaining temperature is less than or equal to the boiling point of the desired component, and wherein the releasing temperature is greater than or equal to the boiling point of the desired component. 
     
     
         8 . The process of  claim 7 , wherein the desired component is released from the separation zone in a gaseous state. 
     
     
         9 . The process of  claim 2 , wherein the retaining temperature is less than or equal to −161.6 degrees Celsius, and wherein the releasing temperature is −161.6 degrees Celsius or greater. 
     
     
         10 . The process of  claim 1 , wherein the trapping material comprises an ethylvinyl benzene-divinyl benzene copolymer. 
     
     
         11 . A process for producing methane comprising heating a gaseous stream comprising carbon dioxide, hydrogen, and a push gas at a temperature in the range of from 300 to 500 degrees Celsius to produce a first intermediate stream comprising an amount of methane; contacting the first intermediate stream with a first trapping material at a temperature in the range of from 15 to 30 degrees Celsius to remove an amount of a component selected from the group consisting of oxygen, water, nitrogen, carbon dioxide, and combinations thereof from the first intermediate stream to produce a second intermediate stream; introducing the second intermediate stream to a separation zone comprising a surface of a second trapping material; employing a multi-directional heat pump to maintain the separation zone at a retaining temperature; retaining methane in the separation zone, while purging hydrogen from the separation zone; employing the multi-directional heat pump to adjust the separation zone to a releasing temperature; and releasing methane from the separation zone. 
     
     
         12 . The process according to  claim 11 , wherein the process employs radiolabeled carbon dioxide ( 11 CO 2 ) and produces  11 C labeled methane. 
     
     
         13 . The process of  claim 11 , wherein a push gas is employed to purge hydrogen from the separation zone. 
     
     
         14 . The process of  claim 13 , wherein the push gas comprises helium. 
     
     
         15 . The process of  claim 11 , wherein the retaining temperature is less than or equal to −161.6 degrees Celsius, and wherein the releasing temperature is −161.6 degrees Celsius or greater. 
     
     
         16 . The process of  claim 11 , wherein the first trapping material is selected from the group consisting of sodium-hydroxide-coated silica, phosphorus pentoxide (P 2 O 5 ) and combinations thereof. 
     
     
         17 . The process of  claim 11 , wherein the second trapping material comprises an ethylvinyl benzene-divinyl benzene copolymer.