Method for the gasification of hydrocarbon feedstocks

Abstract

A method for the gasification of a hydrocarbon-bearing feedstock to produce useful co-products such as high-value hydrocarbon fuels, pure H 2 , electricity, and/or ammonia. The method advantageously gasifies the carbon in the feedstock to carbon monoxide (CO) without producing large quantities of carbon dioxide (CO 2 ). Supplemental hydrogen (H 2 ) is also produced by reacting steam (H 2 O) with a metal. The method can advantageously produce two separate syngas streams, one that is CO-rich and one that is H 2 -rich.

1 . A method for the production of a commodity from raw material reactants, comprising the steps of: 
 (a) providing reactants to a reactor system, said reactants including at least H 2 O, air and a hydrocarbon-bearing feedstock;    (b) reducing a portion of the H 2 O by contacting the H 2 O with a reactive metal to reduce the H 2 O to H 2  and recover a first syngas stream comprising the H 2 ;    (c) oxidizing at least a portion of carbon contained in the hydrocarbon-bearing material to carbon oxides by contacting the carbon with a metal oxide disposed in a slag layer to recover a second syngas stream comprising CO; and    (d) processing the first syngas stream and the second syngas stream to produce at least one energy commodity from the reactor system selected from the group consisting of H 2 , electricity, gaseous hydrocarbon fuels, liquid hydrocarbon fuels and ammonia.    
     
     
         2 . A method as recited in  claim 1 , wherein said second syngas stream comprises at least about 50 vol. % CO.  
     
     
         3 . A method as recited in  claim 1 , wherein said reducing step comprises contacting said H 2 O with a molten reactive metal to convert said reactive metal to a metal oxide.  
     
     
         4 . A method as recited in  claim 3 , wherein said reactive metal comprises iron.  
     
     
         5 . A method as recited in  claim 1 , wherein one of said reactive metal or said carbon is further contacted with O 2  to generate heat.  
     
     
         6 . A method as recited in  claim 1 , further comprising the step of heating said H 2 O to a temperature of at least about 200° C. and not greater than about 600° C. before said reducing step.  
     
     
         7 . A method as recited in  claim 6 , wherein said step of heating H 2 O comprises utilizing heat recovered from at least one of said first syngas stream and said second syngas stream.  
     
     
         8 . A method as recited in  claim 1 , wherein said hydrocarbon-bearing material is selected from the group consisting of pet coke, coal, municipal waste, rubber tires and biomass.  
     
     
         9 . A method as recited in  claim 8 , wherein said hydrocarbon material further comprises sulfur-bearing or chlorine-bearing compounds.  
     
     
         10 . A method as recited in  claim 9 , further comprising the steps of: 
 (i) recovering sulfur-containing compounds from said high CO syngas stream;    (ii) oxidizing said sulfur compounds to form SO 2 ;    (iii) contacting said SO 2  with H 2 S or H 2  to reduce said SO 2 ; and    (iv) extracting elemental sulfur from said contacting step.    
     
     
         11 . A method as recited in  claim 9 , further comprising the steps of: 
 (i) removing chlorine-containing compounds from said high CO syngas stream by contacting the high CO syngas stream with water to dissolve the chlorine-containing compounds in water;    (ii) removing said chlorine-containing compounds by water purification.    
     
     
         12 . A method as recited in  claim 1 , wherein said energy commodity comprises H 2  having a purity of at least about 99%.  
     
     
         13 . A method as recited in  claim 1 , wherein said energy commodity comprises electricity.  
     
     
         14 . A method as recited in  claim 13 , wherein said electricity is generated by burning H 2 , CO or combinations thereof in a combined cycle generator.  
     
     
         15 . A method as recited in  claim 1 , wherein said energy commodity comprises a gaseous fuel and wherein said gaseous fuel is synthesized from a precursor gas stream, said precursor gas stream being formed from at least a portion of said first syngas stream and a portion of said second syngas stream.  
     
     
         16 . A method as recited in  claim 15 , wherein said gaseous fuel comprises a fuel selected from the group consisting of methane, ethane and propane.  
     
     
         17 . A method as recited in  claim 1 , wherein said energy commodity comprises a liquid fuel.  
     
     
         18 . A method as recited in  claim 17 , wherein said method includes the steps of: 
 (i) blending at least a portion of said first syngas stream and at least a portion of said second syngas stream to form a blended precursor syngas stream; and    (ii) producing said liquid fuel from said blended precursor syngas stream by a Fischer Tropsch type synthesis.    
     
     
         19 . A method as recited in  claim 18 , wherein said blended precursor syngas stream comprises a H 2 :CO ratio of at least 1:1.  
     
     
         20 . A method as recited in  claim 1 , wherein said second syngas stream comprises not greater than about 25 vol. % CO 2 .  
     
     
         21 . A method for refining a hydrocarbon feedstock comprising hydrocarbons C x H y , comprising the steps of: 
 (a) reducing H 2 O with a molten metal to produce a high H 2  syngas stream and a metal oxide compound;    (b) gasifying a hydrocarbon feedstock comprising C x H y  by contacting the feedstock with said metal oxide compound to form a high CO syngas stream that is separate from said high H 2  syngas stream;    (c) combining said high CO syngas stream and said high H 2  syngas stream to form a blended syngas stream; and    (d) converting said blended syngas stream to a hydrocarbon-containing product, where x>y in said hydrocarbon feedstock and x<y in said hydrocarbon containing product.    
     
     
         22 . A method as recited in  claim 21 , wherein said step of reducing H 2 O comprises contacting H 2 O with a reactive metal.  
     
     
         23 . A method as recited in  claim 21 , wherein said step of reducing H 2 O comprises contacting H 2 O with iron.  
     
     
         24 . A method as recited in  claim 21 , wherein said step of reducing H 2 O comprises contacting H 2 O with molten iron.  
     
     
         25 . A method as recited in  claim 21 , wherein said step of gasifying said solid hydrocarbon feedstock comprises contacting at least a portion of said solid hydrocarbon feedstock with oxygen.  
     
     
         26 . A method as recited in  claim 21 , wherein said step of gasifying said solid hydrocarbon material comprises contacting a portion of said solid hydrocarbon material with molten iron oxide.  
     
     
         27 . A method as recited in  claim 21 , wherein said hydrocarbon feedstock comprises not greater than about 15 mol. % H 2 .  
     
     
         28 . A method as recited in  claim 21  wherein said hydrocarbon feedstock comprises not greater than about 10 mol. % H 2 .  
     
     
         29 . A method as recited in  claim 21 , wherein said hydrocarbon feedstock is selected from the group consisting of tanker sludge, refinery bottoms, municipal waste, rubber tires, biomass, petroleum coke, animal waste and coal.  
     
     
         30 . A method as recited in  claim 21 , wherein said hydrocarbon feedstock comprises coal having a sulfur content of at least about 2 wt. %.  
     
     
         31 . A method as recited in  claim 21 , wherein said high CO syngas stream comprises at least about 50 vol. % CO.  
     
     
         32 . A method for the production of electricity, solid elemental sulfur, pozzolanic slag and at least one hydrogen-containing commodity from a sulfur-containing hydrocarbon fuel comprising carbon and not greater than about 10 mol. % hydrogen, comprising the steps of: 
 (a) providing reactants to a system of reactors, said reactants including at least air, water and said sulfur-containing hydrocarbon feedstock;    (b) reducing at least a portion of said water to form H 2 ;    (c) oxidizing at least a portion of the carbon to CO;    (d) oxidizing at least a portion of the carbon to CO 2 ; and    (e) recovering a high H 2  syngas stream and a high CO syngas stream from the system of reactors;    (f) selectively combining said high H 2  syngas stream and said high CO syngas stream to form a precursor syngas stream; and    (g) reacting said precursor syngas stream to form a H 2 -containing commodity comprising greater than 10 mol. % H 2 .    
     
     
         33 . A method as recited in  claim 32 , wherein said method substantially precludes the emission of noxious compounds selected from the group of sulfurous compounds, nitrogen oxides, dioxins, furans and particulates.  
     
     
         34 . A method as recited in  claim 32 , wherein a carbon dioxide effluent comprises at least about 90 mol. % CO 2 .  
     
     
         35 . A method as recited in  claim 32 , wherein said hydrogen commodity is substantially free of sulfur and sulfur-containing compounds.  
     
     
         36 . A method as recited in  claim 32 , wherein said hydrogen commodity is selected from the group consisting of hydrogen, ammonia, methane, ethane, propane, gasoline, diesel and jet fuel.  
     
     
         37 . A method as recited in  claim 32 , wherein said hydrogen commodity comprises substantially pure hydrogen.  
     
     
         38 . A method as recited in  claim 32 , wherein said hydrogen commodity comprises a material selected from the group consisting of ammonia, urea or other nitrogen-containing compounds.  
     
     
         39 . A method as recited in  claim 32 , wherein said hydrogen commodity comprises a material selected from the group consisting of methane, ethane, propane, butane or other gaseous hydrocarbons.  
     
     
         40 . A method of producing substantially pure hydrogen from a solid hydrocarbon-containing feedstock by utilizing both the energy derived from the transition of carbon to CO and the energy derived from the transition of CO to CO 2  in which at least about two-thirds of the hydrogen is produced by utilizing the energy derived from the transition of carbon to CO, leaving the energy available from the transition of CO to CO 2  to produce electricity or additional hydrogen.  
     
     
         41 . A method as recited in  claim 40 , wherein at least a portion of said energy derived from the transition of CO to CO 2  is captured in a turbine to produce electricity.