Compositions for Catalytic Gasification of a Petroleum Coke

Abstract

The present invention relates to particulate compositions of a lower ash type petroleum coke containing at least two preselected components (alkali metal and calcium) that exhibit an efficient, enhanced-yielding gasification to value added gaseous products, particularly when used in a steady-state integrated gasification process. The compositions of the present invention are particularly useful for catalytic gasification of petroleum coke at moderate temperatures ranging from about 450° C. to about 900° C. Advantageously, the compositions can be readily incorporated into fluidized bed gasification units, and can result in a cost-effective, high-yielding production of methane gas from petroleum coke.

1 . A particulate composition having a particle distribution size suitable for gasification in a fluidized bed zone, comprising an intimate mixture of (A) a petroleum coke derived from crude oil comprising ash in an amount of about 1.0 wt % or less, based on the weight of the petroleum coke, and (B) a gasification catalyst which under suitable conditions of temperature and pressure and in the presence of steam exhibits gasification activity whereby value added gaseous products are formed, wherein:
 (a) the gasification catalyst comprises (i) a first component which is a source of at least one alkali metal, and (ii) a second component which is a source of calcium; and   (b) the gasification catalyst is present in an amount sufficient to provide, in the particulate composition, a ratio of alkali metal atoms to carbon atoms in the range of from about 0.01 to about 0.1, and a ratio of calcium atoms to carbon atoms in the range of from about 0.01 to about 0.1.   
   
   
       2 . The particulate composition according to  claim 1 , wherein the alkali metal is potassium. 
   
   
       3 . 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. 
   
   
       4 . The particulate composition according to  claim 1 , wherein the source of alkali metal is potassium carbonate. 
   
   
       5 . The particulate composition according to  claim 1 , wherein the source of calcium is a calcium salt selected from the group consisting of hydroxide, acetate, halide and nitrate salts. 
   
   
       6 . The particulate composition according to  claim 1 , wherein the source of calcium is calcium nitrate or calcium acetate. 
   
   
       7 . The particulate composition according to  claim 1 , wherein the alkali metal is potassium; the source of alkali metal is an alkali metal salt selected from the group consisting of carbonate, hydroxide, acetate, halide and nitrate salts; and the source of calcium is a calcium salt selected from the group consisting of hydroxide, acetate, halide and nitrate salts. 
   
   
       8 . The particulate composition according to  claim 7 , wherein the source of alkali metal is potassium carbonate, and the source of calcium is calcium nitrate or calcium acetate. 
   
   
       9 . The particulate composition according to  claim 1 , wherein the gasification catalyst is present in an amount sufficient to provide in the particulate composition a molar ratio of alkali metal atoms to carbon atoms in the range of from about 0.01 to about 0.08. 
   
   
       10 . The particulate composition according to  claim 1 , wherein the gasification catalyst is present in an amount sufficient to provide in the particulate composition a molar ratio of calcium atoms to carbon atoms in the range of from about 0.01 to about 0.08. 
   
   
       11 . The particulate composition according to  claim 1 , having a particle size ranging from about 25 microns to about 2500 microns. 
   
   
       12 . A process for converting petroleum coke to methane, comprising the steps of:
 (1) combining a petroleum coke and a catalyst having steam gasification activity to produce a particulate composition having a particle distribution size suitable for gasification in a fluidized bed zone,   (2) reacting the particulate composition in a fluidized bed zone in the presence of steam to form gaseous products including methane and one or more of hydrogen, carbon monoxide and other higher hydrocarbons, and   (3) recovering methane from the gaseous products,   
     wherein the particulate composition is as set forth in  claim 1 .