Aromatization of methane with combination of catalysts

Abstract

A heated reaction gas comprising methane is contacted with first and second catalysts to catalyze production of an aromatic hydrocarbon. The first catalyst is more active than the second catalyst for catalyzing aromatization of methane, and the second catalyst is more active than the first catalyst for catalyzing aromatization of ethane. A reactor for producing aromatic hydrocarbons from the reaction gas may have a conduit defining a reaction zone for the reaction gas to react therein, and the first and second catalysts may be disposed in the reaction zone.

What is claimed is:  
     
         1 . A method comprising:
 contacting a heated reaction gas comprising methane with a first catalyst and a second catalyst to catalyze production of an aromatic hydrocarbon,   wherein said first catalyst is more active than said second catalyst for catalyzing aromatization of methane, and said second catalyst is more active than said first catalyst for catalyzing aromatization of ethane.   
     
     
         2 . The method of  claim 1 , wherein at least one of said first and second catalysts is an aluminosilicate zeolite modified by a transition metal. 
     
     
         3 . The method of  claim 2 , wherein said first catalyst is a MCM-22 zeolite modified by a first transition metal, and said second catalyst is a ZSM-5 zeolite modified by a second transition metal. 
     
     
         4 . The method of  claim 3 , wherein each of said first transition metal and said second transition metal is molybdenum. 
     
     
         5 . The method of  claim 4 , wherein each one of said first and second catalysts comprises about 3 to about 12 wt % of molybdenum. 
     
     
         6 . The method of  claim 4 , wherein each one of said first and second catalysts has a Si/2Al ratio of from 25 to 45. 
     
     
         7 . The method of  claim 1 , wherein said heated reaction gas is heated to a temperature of about 600 to about 700° C. 
     
     
         8 . The method of  claim 1 , wherein, prior to said contacting, said first and second catalysts are heated to at least 300° C. in the presence of propane. 
     
     
         9 . The method of  claim 1 , wherein the weight ratio of said first and second catalysts is about 1:1. 
     
     
         10 . A reactor for producing aromatic hydrocarbons from a reaction gas comprising methane, comprising:
 a conduit defining a reaction zone for the reaction gas to react therein; and   a first catalyst and a second catalyst in said reaction zone, wherein said first catalyst is more active than said second catalyst for catalyzing aromatization of methane, and said second catalyst is more active than said first catalyst for catalyzing aromatization of ethane.   
     
     
         11 . The reactor of  claim 10 , wherein at least one of said first and second catalysts is an aluminosilicate zeolite modified by a transition metal. 
     
     
         12 . The reactor of  claim 11 , wherein said first catalyst is a MCM-22 zeolite modified by a first transition metal, and said second catalyst is a ZSM-5 zeolite modified by a second transition metal. 
     
     
         13 . The reactor of  claim 12 , wherein each of said first transition metal and said second transition metal is molybdenum. 
     
     
         14 . The reactor of  claim 13 , wherein each one of said first and second catalysts comprises about 3 to about 12 wt % of molybdenum. 
     
     
         15 . The reactor of  claim 13 , wherein each one of said first and second catalysts has a Si/2A1 ratio of from 25 to 45. 
     
     
         16 . The reactor of  claim 10 , wherein the weight ratio of said first and second catalysts is about 1:1.