Method for preparing synthesis gas, method for preparing dimethyl ether using synthesis gas, and furnace for preparing synthesis gas

Abstract

Disclosed is a process for producing a synthesis gas containing no hydrocarbon and reduced concentration of carbon dioxide among the produced synthesis gas. The process according to the present invention comprises reforming the gas generated by partial combustion of hydrocarbon using a catalyst in a furnace for generating the synthesis gas mounted on a catalyst layer inside the furnace, and producing the synthesis gas comprising hydrogen and carbon monoxide as a main components, and is characterized in that the temperature at outlet of the catalyst layer ranges from 1100 to 1300° C. and the concentration of carbon dioxide in the produced synthesis gas is not more than 10% by volume.

1 . A process for producing a synthesis gas comprising carbon monoxide and hydrogen as main components which comprises reforming a gas produced from a partial combustion of hydrocarbon by using a synthesis furnace for generating the synthesis gas mounted on a catalyst layer therein, wherein a temperature at an outlet of the catalyst layer ranges from 1100 to 1300° C. and a concentration of carbon dioxide in the produced synthesis gas is not more than 10% by volume.  
   
   
       2 . The process according to  claim 1  wherein a retention time of gas upstream of the catalyst layer is 2 seconds or more.  
   
   
       3 . The process according to  claim 1  or  2  wherein the produced synthesis gas is quenched to 600° C. or lower immediately after completion of catalytic reaction.  
   
   
       4 . A process for preparing dimethyl ether from a synthesis gas containing carbon monoxide and hydrogen which comprises using the synthesis gas produced by the process described in  claim 1 .  
   
   
       5 . The process for preparing dimethyl ether from a synthesis gas containing carbon monoxide and hydrogen in a ratio of 1:0.8 to 1.2 which comprises using the synthesis gas produced by the process described in  claim 1 .  
   
   
       6 . A furnace for preparing a synthesis gas which comprises effusing a raw material containing at least hydrocarbon and an oxidant from a burner mounted on top portion of the furnace; partially combusting hydrocarbon in a space above a catalyst layer formed inside of the furnace; and preparing a synthesis gas containing hydrogen and carbon monoxide in the catalyst layer, wherein the furnace has a space to meet the conditions of the following (1) and (2), above the catalyst layer: 
 (1) L≧D/2×cotan θ 1 , and    (2) gas retention time in the space is 2 seconds or mores    wherein L is a height of the space above the catalyst layer, D is an inside diameter of the furnace, θ 1  is a ½ angle of an apex angle in the vertical cross-section of a conical breadth of an effusion flow effused into the inside of the furnace from a burner, which is in the range of 6.5°≦θ 1 ≦9°.    
   
   
       7 . The furnace according to  claim 6  which further satisfies the condition of (3): 
 (3) θ 2 ≧25°   wherein θ 2  is a ½ angle of the apex angle in the vertical cross-section of the conical-shaped top portion of the furnace.    
   
   
       8 . A furnace for preparing a synthesis gas containing hydrogen and carbon monoxide in a catalyst layer by effusing a raw material containing at least a hydrocarbon and an oxidizing agent from a burner mounted at the top portion of the furnace, said burner having gas effusing holes, and partially combusting the hydrocarbon in a space above the catalyst layer formed inside of the furnace, wherein the furnace has a space to meet the conditions of the following (1), (2) and (4), above the catalyst layer: 
 (1) L≧D/2×cotan θ 1 ,    (2) a gas retention time in the space is 2 seconds or more, and    (4) L≧10d,    wherein L is a height of the space above the catalyst layer, D is an inside diameter of the furnace, θ 1  is a ½ angle of an apex angle in the vertical cross-section of a conical breadth of an effusion flow effused into the inside of the furnace from the burner, which is in the range of 6.5°≦θ 1 ≦9°, and d is a minimum diameter of a circle being capable of covering all the gas effusing holes of the burner.    
   
   
       9 . A furnace for preparing a synthesis gas containing hydrogen and carbon monoxide in a catalyst layer by effusing a raw material containing at least a hydrocarbon and an oxidizing agent from a burner mounted at the top portion of the furnace, said burner having gas effusing holes, and partially combusting the hydrocarbon in a space above the catalyst layer formed inside of the furnace, wherein the furnace has a space to meet the conditions of the following (1), (2), (3) and (5), above the catalyst layer: 
 (1) L≧D/2×cotan θ 1 ,    (2) a gas retention time in the space is 2 seconds or more,    (3) θ 2 ≧25°, and    (5) D≧3d,    wherein L is a height of the space above the catalyst layer, D is an inside diameter of the furnace, θ 1  is a ½ angle of an apex angle in the vertical cross-section of a conical breadth of an effusion flow effused into the inside of the furnace from the burner, which is in the range of 6.5°≦θ 1 ≦9°, θ 2  is a ½ angle of the apex angle in the vertical cross-section of the top conical-shaped portion of the furnace, and d is a minimum diameter of a circle being capable of covering all the gas effusing holes of the burner.    
   
   
       10 . The furnace according to  claim 9  which further satisfies the follow condition (4): 
 (4) L≧10d.    
   
   
       11 . The furnace according to any one of  claims 6  to  10  wherein the carbon dioxide concentration in the synthesis gas prepared by setting the outlet temperature of the catalyst layer to 1100 to 1300° C. is 10 vol % or less.  
   
   
       12 . The furnace according to  claim 11  wherein after terminating the catalysis, the synthesis gas is rapidly cooled to 600° C. or less.  
   
   
       13 . The furnace according to  claim 6  wherein dimethyl ether is prepared from the synthesis gas containing carbon monoxide and hydrogen, which is prepared by the furnace for preparing the synthesis gas.  
   
   
       14 . The furnace according to  claim 6  wherein dimethyl ether is prepared from the synthesis gas containing carbon monoxide and hydrogen having the ratio of 1:0.8 to 1.2, which is prepared by the furnace for preparing the synthesis gas.