Process for the preparation of gaseous synfuel

Abstract

A process is provided for the preparation of a gaseous syn-fuel having a heating value in the same range as natural gas.

1 . Process for the preparation of a gaseous dimethyl ether synfuel having a BTU value corresponding substantially to the BTU value of natural gas, said process comprising the steps of
 providing a synthesis gas comprising hydrogen, carbon monoxide and nitrogen;   catalytically converting the synthesis gas into a dimethyl ether raw product further comprising unconverted synthesis gas, the nitrogen and dissolved carbon dioxide;   cooling and condensing the dimethyl ether raw product with the dissolved carbon dioxide to a liquid and a gaseous phase with the unconverted synthesis gas and the nitrogen;   separating the liquid phase from the gaseous phase;   treating the liquid phase to remove the carbon dioxide from the dimethyl ether raw product and to obtain a purified dimethyl ether product; and   admixing and adjusting content of inert gas having a BTU value of about zero into the purified dimethyl ether raw product to obtain the gaseous dimethyl ether synfuel having a BTU value equal to that of the BTU value of natural gas, wherein the synthesis gas is prepared by air-blown gasification of a carbonaceous material.   
     
     
         2 . The process of  claim 1 , wherein the feedstock is gasified with air at a pressure of between 2 to 3 MPa. 
     
     
         3 . The process of  claim 1 , comprising the further steps of removal of the dust from the synthesis gas and steam reforming of tar contained in the synthesis gas from the air-blown gasification. 
     
     
         4 . The process according to  claim 1 , wherein the synthesis gas is further steam reformed upstream the catalytically converting of the synthesis gas into dimethyl ether raw product. 
     
     
         5 . The process according to  claim 1 , wherein the synthesis gas is pressurized to a pressure of between 8 to 10 MPa prior to the catalytically conversion into the dimethyl ether raw product. 
     
     
         6 . The process according to  claim 1 , wherein the liquid phase is treated with a liquid solvent of an amine or a liquid solvent containing potassium carbonate for the removal of carbon dioxide from the dimethyl ether raw product. 
     
     
         7 . The process according to  claim 1 , comprising the further step of removing carbonyl sulphide, metal carbonyls, carbon disulphide, hydrogen sulphide, hydrogen cyanide, ammonia and arsenic and chlorine from the synthesis gas. 
     
     
         8 . Use of the gaseous dimethyl ether synfuel prepared according to  claim 1  as pipeline gas in an existing natural gas distribution net.