Reactor and Process for the Hydrogenation of Carbon Dioxide

Abstract

The present invention is directed to a membrane reactor for the hydrogenation of carbon dioxide, said membrane reactor comprising a reaction compartment (2) comprising a catalyst bed, a permeate compartment (4) and a membrane separating the reaction compartment and the permeate compartment, wherein said permeate compartment comprises a condensing surface.

1 . A membrane reactor for the hydrogenation of carbon dioxide,
 said membrane reactor comprising a reaction compartment comprising a catalyst bed, a permeate compartment and a water-permeable membrane separating the reaction compartment and the permeate compartment, wherein said permeate compartment comprises a condensing surface and a means for cooling that is connected to said condensing surface such that during operation of the reactor, water can condense on the condensing surface.   
     
     
         2 . The membrane reactor in accordance with  claim 1 , wherein the means for cooling comprises an active-cooling device. 
     
     
         3 . The membrane reactor in accordance with  claim 1 , wherein said reactor comprises
 an inner wall bounding an inner space that defines the reaction compartment;   an outer wall that is arranged around said inner wall, wherein said outer wall and inner wall bound an outer space that defines the permeate compartment;   
       wherein said inner wall comprises the water-permeable membrane, and wherein said condensing surface is connected to the outer wall. 
     
     
         4 . The membrane reactor in accordance with  claim 1 , wherein said reactor comprises
 an inner wall bounding an inner space that defines the permeate compartment;   an outer wall that is arranged around said inner wall, wherein said outer wall and inner wall bound an outer space that defines the reaction compartment;   
       wherein said inner wall comprises the water-permeable membrane, and wherein the condensing surface is located away from the inner wall. 
     
     
         5 . The membrane reactor in accordance with  claim 1 , wherein said permeate compartment and means for cooling comprise an active-cooling device which active-cooling device is disconnected from the inner wall. 
     
     
         6 . The membrane reactor in accordance with  claim 3 , wherein said inner wall and outer wall are tubular and the outer wall is at least partially co-axially arranged around said inner wall. 
     
     
         7 . The membrane reactor in accordance with  claim 1 , wherein the condensing surface comprises protruding surface elements. 
     
     
         8 . The membrane reactor in accordance with  claim 1 , wherein said water-permeable membrane comprises a hydrophilic membrane. 
     
     
         9 . The membrane reactor in accordance with  claim 1 , wherein said catalyst bed comprises copper, zinc oxide, zirconia, palladium, cerium(IV) oxide or combinations thereof. 
     
     
         10 . The process for the hydrogenation of carbon dioxide, wherein said process comprises reacting carbon dioxide with hydrogen to form methanol and/or dimethyl ether, and water as a side product, and wherein said process further comprises removing said water from the process by a combination of permeation of said water through a water-permeable membrane and condensation of the water. 
     
     
         11 . The process for the hydrogenation of carbon dioxide carried out in a membrane reactor in accordance with  claim 1 , wherein the condensing surface has a temperature of less than 150° C. 
     
     
         12 . The process in accordance with  claim 11 , wherein reacting carbon dioxide with hydrogen is carried out at a temperature in the range of 150-400° C. and/or at a pressure in the range of 1-10 MPa. 
     
     
         13 . The process in accordance with  claim 10 , wherein said carbon dioxide and/or said hydrogen originate from biogas. 
     
     
         14 . The membrane reactor of  claim 1  wherein the means for cooling comprises a passage through which a cooling fluid can flow. 
     
     
         15 . The membrane reactor of  claim 1  wherein said water-permeable membrane comprises a zeolite membrane, an amorphous membrane or a polymer membrane. 
     
     
         16 . The process of  claim 11  wherein the condensing surface has a temperature of less than 50° C. 
     
     
         17 . The process of  claim 11  wherein the condensing surface has a temperature of less than 10° C. 
     
     
         18 . The process of  claim 12  wherein reacting carbon dioxide with hydrogen is carried out at a temperature in the range of 200-300° C. and/or at a pressure in the range of 2-8 MPa. 
     
     
         19 . The process of  claim 12  wherein reacting carbon dioxide with hydrogen is carried out at a temperature of about 250° C. and/or at a pressure of about 5 MPa.