Petroleum Coke Compositions for Catalytic Gasification

Abstract

Particulate compositions are described comprising an intimate mixture of a petroleum coke, coal and a gasification catalyst, where the gasification catalyst is loaded onto at least the coal for gasification in the presence of steam to yield a plurality of gases including methane and at least one or more of hydrogen, carbon monoxide, and other higher hydrocarbons are formed. Processes are also provided for the preparation of the particulate compositions and converting the particulate composition into a plurality of gaseous products.

We claim: 
     
         1 . A particulate composition having a particle distribution size suitable for gasification in a fluidized bed zone, the particulate composition comprising an intimate mixture of (a) a solid petroleum coke; (b) a coal; and (c) a gasification catalyst which, in the presence of steam and under suitable temperature and pressure, exhibits gasification activity whereby a plurality of gases comprising methane and one or more of hydrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, ammonia and other higher hydrocarbons are formed, wherein:
 (i) the solid petroleum coke and the coal are present in the particulate composition at a weight ratio of from about 5:95 to about 95:5;   (ii) the gasification catalyst is loaded only onto the coal;   (iii) the gasification catalyst comprises a source of at least one alkali metal and is present in an amount sufficient to provide, in the particulate composition, a ratio of alkali metal atoms to carbon atoms ranging from 0.01 to about 0.08; and   (iv) the particulate composition comprises a total ash content of less than about 20 wt %, based on the weight of the particulate composition, and the ash content of the particulate composition comprises less than about 20 wt % alumina, based on the weight of the ash.   
     
     
         2 . The particulate composition according to  claim 1 , where in the alkali metal comprises potassium, sodium or both. 
     
     
         3 . The particulate composition according to  claim 2 , wherein the alkali metal is potassium. 
     
     
         4 . The particulate composition according to  claim 1 , wherein the source of alkali metal is an alkali metal salt selected from the group consisting of carbonate, hydroxide, acetate, halide and nitrate salts. 
     
     
         5 . The particulate composition according to  claim 1 , having a particle size ranging from about 25 microns to about 2500 microns. 
     
     
         6 . A process for converting a particulate composition into a plurality of gaseous products, the process comprising the steps of:
 (a) supplying a particulate composition according to  claim 1  to a gasifying reactor;   (b) reacting the particulate composition in the gasifying reactor in the presence of steam and under suitable temperature and pressure to form a plurality of gaseous including methane and one or more of hydrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, ammonia and other higher hydrocarbons; and   (c) at least partially separating the plurality of gaseous products to produce a stream comprising a predominant amount of one of the gaseous products.   
     
     
         7 . The process according to  claim 9 , wherein the stream comprises a predominant amount of methane. 
     
     
         8 . The process according to  claim 9 , wherein a char is formed in step (b), and the char is removed from the gasifying reactor and sent to a catalyst recovery and recycle process. 
     
     
         9 . The process according to claim  11 , wherein the gasification catalyst comprises gasification catalyst recycled from the catalyst recovery and recycle process. 
     
     
         10 . A process for preparing a particulate composition according to  claim 1 , the process comprising the steps of:
 (a) providing solid petroleum coke particulates, coal particulates and gasification catalyst;   (b) contacting the coal particulates with an aqueous solution comprising gasification catalyst to form a slurry; and   (c) dewatering the slurry to form a catalyst-loaded wet coal cake; and   (d) kneading the wet coal cake and the solid petroleum coke particulates to form the particulate composition.