US2007000177A1PendingUtilityA1

Mild catalytic steam gasification process

42
Assignee: HIPPO EDWIN JPriority: Jul 1, 2005Filed: Jun 1, 2006Published: Jan 4, 2007
Est. expiryJul 1, 2025(expired)· nominal 20-yr term from priority
Inventors:Edwin J. HippoAtul C. Sheth
C10J 3/54C10J 3/46C10J 3/48C10J 2200/158C10J 2300/1807C10J 3/06C10J 2300/0969C10J 3/463C10J 2300/0983C10J 2300/0903C10J 2300/093Y02E20/18
42
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Claims

Abstract

The present invention provides an improved alkali metal catalyzed steam gasification process that utilizes a CO 2 trap material and/or a mineral binder material within the gasifier. The process optimally achieves over 90% carbon conversion with over 80% yield of methane. The raw gas product can be used directly as fuel. The catalyst can be recovered from the solid purge and recycled to the gasifier and/or the CO 2 trap can be regenerated and recycled to the gasifier.

Claims

exact text as granted — not AI-modified
1 . A method for catalytic gasification of carbonaceous material to combustible gases, the method comprising: 
 reacting carbonaceous material and steam in the presence of an alkali catalyst at a temperature in the range of from about 300° C. to about 700° C. to form a gas comprising CO 2 , CH 4 , H 2 O and H 2 ;    combining said CO 2  in said gas with a CO 2  trap material;    removing H 2 O from said gas to form a dry raw gaseous product;    wherein said CO 2  trap material is present in an amount sufficient to combine with sufficient quantities of CO 2  to form a dry raw gaseous product comprising at least about 40% methane by volume.    
   
   
       2 . A method for catalytic gasification of carbonaceous material to combustible gases, the method comprising: 
 reacting carbonaceous material and steam in the presence of an alkali catalyst at a temperature in the range of from about 300° C. to about 700° C. to form a gas comprising CO 2 , CH 4  and H 2 , wherein said carbonaceous material includes silica, alumina, and other mineral constituents; and    providing a mineral binder material to combine with at least a portion of said mineral constituents to inhibit said mineral constituents from combining with said alkali catalyst.    
   
   
       3 . A method for catalytic gasification of carbonaceous material to combustible gases, the method comprising: 
 reacting carbonaceous material and steam in the presence of an alkali catalyst at a temperature in the range of from about 300° C. to about 700° C. to form a gas comprising CO 2 , CH 4 , H 2 O and H 2 , wherein said carbonaceous material includes silica, alumina, and other mineral constituents;    providing a mineral binder material to combine with at least a portion of said mineral constituents to inhibit said mineral constituents from combining with said alkali catalyst.    combining said CO 2  in said gas with a CO 2  trap material;    removing H 2 O from said gas to form a dry raw gaseous product;    wherein said CO 2  trap material is present in an amount sufficient to combine with sufficient quantities of CO 2  to form a dry raw gaseous product comprising at least about 40% methane by volume.    
   
   
       4 . A method according to  claim 1 ,  2 , or  3 , wherein the temperature is in the range from about 300° C. to about 550° C.  
   
   
       5 . A method according to  claim 1 ,  2 , or  3 , wherein substantial quantities of H 2  and/or CO are not recycled or added to the reactor.  
   
   
       6 . A method according to  claim 1 ,  2 , or  3 , wherein the alkali catalyst comprises one or more compounds selected from the group consisting of Na 2 CO 3 , K 2 CO 3 , Rb 2 CO 3 , Li 2 CO 3 , Cs 2 CO 3 , KNO 3 , K 2 SO 4 , LiOH, NaOH, KOH and naturally occuring minerals containing alkali metal salts.  
   
   
       7 . A method according to  claim 1  or  3 , wherein said CO 2  trap material comprises one or more compounds selected from the group consisting of CaO, Ca(OH) 2 , dolomite, limestone, Trona, and other compounds effective for regeneratively combining with CO 2  to form solid carbonates and bicarbonates.  
   
   
       8 . A method according to  claim 7  wherein said CO 2  trap material comprises CaO.  
   
   
       9 . A method according to  claim 8  wherein the weight ratio of CaO to carbon in the reactor is in the range of about 0.5:1 to about 4:1.  
   
   
       10 . A method according to  claim 9  wherein the weight ratio of CaO to carbon in the reactor is about 2:1.  
   
   
       11 . A method for catalytic gasification of carbonaceous material to combustible gases, the method comprising: 
 reacting carbonaceous material and steam in an environment in the presence of an alkali catalyst and a quantity of CO 2  trap material at a temperature in the range from about 300° C. to about 700° C. to form a gas comprising CH 4  and H 2 O and solid particles comprising carbonated CO 2  trap material;    removing H 2 O from said gas to form a dry raw gaseous product comprising at least about 30% methane;    removing said solid particles from the environment, regenerating CO 2  trap material therefrom, and returning said regenerated CO 2  trap material to said environment.    
   
   
       12 . A method according to  claim 11  wherein said regenerated CO 2  trap material comprises at least 50% of said quantity of CO 2  trap material.  
   
   
       13 . A method according to  claim 12  wherein said regenerated CO 2  trap material comprises at least 90% of said quantity of CO 2  trap material.  
   
   
       14 . A method according to  claim 2  or  3 , wherein said mineral binder material comprises one or more compounds selected from the group consisting of CaO, Ca(OH) 2 , CaCO 3 , and other alkaline earth metal salts.  
   
   
       15 . A method according to  claim 2  or  3  further comprising dispersing said mineral binder material into said carbonaceous material prior to said reacting.  
   
   
       16 . A method according to  claim 14  wherein the stoichiometric ratio of said mineral binder material relative to said mineral constituents of said carbonaceous material is in the range of about 0.5 to about 1.5.  
   
   
       17 . A method according to  claim 14  wherein the stoichiometric ratio of said mineral binder material relative to said mineral constituents of said carbonaceous material is about 1:1.  
   
   
       18 . A method according to  claim 1 ,  2  or  3  wherein the carbon conversion of the carbonaceous material is at least about 50%.  
   
   
       19 . A method according to  claim 18  wherein the carbon conversion of the carbonaceous material is at least about 65%.  
   
   
       20 . A method according to  claim 19 , wherein the carbon conversion of the carbonaceous material is at least 80%.  
   
   
       21 . A method according to  claim 1  or  3  wherein the dry raw gaseous product includes at least about 50% methane by volume.  
   
   
       22 . A method according to  claim 21  wherein the dry raw gaseous product includes at least about 60% methane by volume.  
   
   
       23 . A method according to  claim 21  wherein the dry raw gaseous product includes at least about 70% methane by volume.  
   
   
       24 . A method according to  claim 21  wherein the dry raw gaseous product includes at least about 80% methane by volume.  
   
   
       25 . A method according to  claim 1 ,  2 , or  3 , further comprising maintaining the molar ratio of steam to carbon in the reactor within the range of about 1.5:1 to 3:1.  
   
   
       26 . A method according to  claim 1 ,  2 , or  3 , further comprising controlling the partial pressure of the steam by addition of a non-reactive gas to the reactor.  
   
   
       27 . The method according to  claim 1 ,  2 , or  3  wherein the reactor comprises a fluid bed or a moving bed.  
   
   
       28 . A method according to  claim 6  wherein the alkali catalyst comprises a eutectic salt mixture.  
   
   
       29 . A method according to  claim 28 , wherein the eutectic salt mixture is a binary salt mixture.  
   
   
       30 . A method according to  claim 29  wherein the binary salt mixture is 29% Na 2 CO 3  and 71% K 2 CO 3  by mole percent.  
   
   
       31 . A method according to  claim 28 , wherein the eutectic salt mixture is a ternary salt mixture.  
   
   
       32 . A method according to  claim 31  wherein the ternary salt mixture is 43.5% Li 2 CO 3 , 31.5% Na 2 CO 3  and 25% K 2 CO 3  by mole percent.  
   
   
       33 . A method according to  claim 31  wherein the ternary salt mixture is 39% Li 2 CO 3 , 38.5% Na 2 CO 3  and 22.5% Rb 2 CO 3  by mole percent.  
   
   
       34 . A method according to  claim 4  wherein the alkali catalyst comprises NaOH, Na 2 CO 3 , or Trona.  
   
   
       35 . A method for catalytic gasification of carbonaceous material to combustible gases, the method comprising: 
 reacting carbonaceous material and steam in the presence of an alkali catalyst at a temperature in the range of from about 300° C. to about 700° C. to form a gas comprising CO 2 , CH 4 , H 2 O and H 2 ;    combining said CO 2  in said gas with a CO 2  trap material;    removing H 2 O from said gas to form a dry raw gaseous product;    wherein said CO 2  trap material is present in an amount sufficient to combine with sufficient quantities of CO 2  so said dry raw gaseous product comprises less than about 2% CO 2  by volume.

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