Process for pyrolysis and gasification of a coal feed

Abstract

A process for gasifying and pyrolyzing coal is described. A first coal feed is pyrolyzed into a coal tar stream and a coke stream in a pyrolysis zone. A second coal feed is gasified in a gasification zone to produce an effluent stream. Contaminants are removed from the effluent stream to provide a purified effluent stream. The purified effluent stream is introduced to the pyrolysis zone.

What is claimed is: 
     
         1 . A process comprising:
 pyrolyzing a first coal feed into a coal tar stream and a coke stream in a pyrolysis zone;   gasifying a second coal feed in a gasification zone to produce an effluent stream;   removing contaminants from the effluent stream to provide a purified effluent stream; and   introducing the purified effluent stream to said pyrolysis zone.   
     
     
         2 . The process of  claim 1  wherein the gasification zone is selected from the group consisting of a moving bed gasifier, a fluidized bed gasifier, and an entrained flow gasifier. 
     
     
         3 . The process of  claim 1  wherein the second coal feed is pulverized and dry-fed into the gasification zone. 
     
     
         4 . The process of  claim 1  wherein gasifying the second coal feed takes place at a temperature between about 800° C. and about 1,400° C. 
     
     
         5 . The process of  claim 1  wherein the effluent stream comprises hydrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, steam, or a combination. 
     
     
         6 . The process of  claim 1  wherein removing contaminants from the effluent stream comprises filtering particulate matter from the effluent stream. 
     
     
         7 . The process of  claim 1  wherein removing contaminants from the effluent stream comprises removing one or more of carbon dioxide, hydrogen sulfide, arsenic, and mercury. 
     
     
         8 . The process of  claim 1  wherein removing contaminants comprises performing a water shift gas reaction to generate hydrogen and carbon dioxide from carbon monoxide and steam in the effluent stream. 
     
     
         9 . The process of  claim 1  further comprising:
 fractionating the coal tar stream to provide at least a hydrocarbon stream. 
 
     
     
         10 . The process of  claim 9  further comprising recovering at least one product from the hydrocarbon stream. 
     
     
         11 . The process of  claim 10 , wherein the hydrocarbon stream is processed by at least one of hydrotreating, hydrocracking, fluid catalytic cracking, alkylation, transalkylation, oxidation, and hydrogenation. 
     
     
         12 . The process of  claim 1  further comprising:
 dividing a coal feed to provide the first coal feed and the second coal feed. 
 
     
     
         13 . A process comprising:
 pyrolyzing a first coal feed into a coal tar stream and a coke stream in a pyrolysis zone;   gasifying a second coal feed in a gasification zone to produce an effluent stream;   removing contaminants from the effluent stream to produce a purified effluent stream comprising hydrogen and one or more of carbon monoxide and steam;   separating the purified effluent stream in a separation zone to provide at least a first stream comprising hydrogen and a second stream comprising the one or more of carbon monoxide and steam; and   introducing the first stream or the second stream to the pyrolysis zone.   
     
     
         14 . The process of  claim 13 , wherein separating the purified effluent stream comprises separation by pressure swing adsorption. 
     
     
         15 . The process of  claim 13 , wherein separating the purified effluent stream comprises membrane separation to provide a permeate comprising the first stream and a retentate comprising the second stream. 
     
     
         16 . The process of  claim 13 , wherein the first stream is introduced to the pyrolysis zone. 
     
     
         17 . The process of  claim 13 , wherein the second stream is introduced to the pyrolysis zone. 
     
     
         18 . The process of  claim 13  wherein removing contaminants comprises:
 filtering the effluent stream to remove contaminants; and 
 performing a water shift gas reaction to remove acid gases in the effluent stream. 
 
     
     
         19 . The process of  claim 13  wherein the second coal feed is pulverized and dry-fed into the gasification zone. 
     
     
         20 . A process comprising:
 pyrolyzing a first, dry coal feed into a coal tar stream and a coke stream in a pyrolysis zone;   gasifying a second, dry coal feed in a gasification zone to produce an effluent stream;   introducing the effluent stream to the pyrolysis zone.