System and Method for Dual Fluidized Bed Gasification

Abstract

A system, for production of high-quality syngas, comprising a first dual fluidized bed loop having a fluid bed conditioner operable to produce high quality syngas comprising a first percentage of components other than CO and H 2 from a gas feed, wherein the conditioner comprises an outlet for a first catalytic heat transfer stream comprising a catalytic heat transfer material and having a first temperature, and an inlet for a second catalytic heat transfer stream comprising catalytic heat transfer material and having a second temperature greater than the first temperature; a fluid bed combustor operable to combust fuel and oxidant, wherein the fluid bed combustor comprises an inlet connected with the outlet for a first catalytic heat transfer stream of the conditioner, and an outlet connected with the inlet for a second catalytic heat transfer stream of the conditioner; and a catalytic heat transfer material.

What is claimed is: 
     
         1 . A method for continuous dry reforming, the method comprising:
 introducing a feed comprising carbon dioxide and at least one selected from methane and propane into a fluid bed conditioner operated at a conditioning temperature, wherein the fluid bed conditioner is one fluid bed of a dual fluidized bed loop and is configured to convert at least a portion of said feed into synthesis gas components;   extracting a first catalytic heat transfer stream comprising a catalytic heat transfer material and having a first temperature from the fluid bed conditioner and introducing at least a portion of the first catalytic heat transfer stream and a flue gas into a fluid bed combustor, wherein the fluid bed combustor is configured to regenerate the catalyst via combustion;   extracting a second catalytic heat transfer stream comprising catalytic heat transfer material and having a second temperature from the fluid bed combustor and introducing at least a portion of the second catalytic heat transfer stream into the fluid bed conditioner; and   extracting synthesis gas from the fluid bed conditioner.   
     
     
         2 . The method of  claim 1  wherein the catalytic heat transfer material is selected from the group consisting of nickel olivine, silica, nickel alumina and combinations thereof. 
     
     
         3 . The method of  claim 1  wherein the flue gas comprises excess air. 
     
     
         4 . The method of  claim 3  wherein the flue gas comprises up to 100 ppmv sulfur dioxide. 
     
     
         5 . The method of  claim 1  further comprising extracting a spent flue gas from the fluid gas combustor, wherein the spent flue gas comprises less than 1 vol % oxygen, less than about 0.5 vol % carbon monoxide, or both. 
     
     
         6 . The method of  claim 1  wherein the fluid bed combustor is operated at approximately stoichiometric air. 
     
     
         7 . The method of  claim 1  wherein the feed comprises at least 50 ppmv hydrogen sulfide, at least 50,000 mg/Nm 3  tar, or both and wherein the synthesis gas comprises less than 1 ppmv hydrogen sulfide, less than about 1 mg/Nm 3  tar, or both. 
     
     
         8 . The method of  claim 1  wherein dry reforming is performed in the presence of tars with substantially no evidence of catalyst deactivation and with greater than 90% molar conversion of methane, CO 2 , and tars. 
     
     
         9 . The method of  claim 8  wherein tars were reformed to below a level of 200 mg/Nm 3  or below a level of 1 mg/Nm 3 . 
     
     
         10 . The method of  claim 1  wherein molar ratio of H 2 :CO in the conditioned synthesis gas is adjusted to a level of about 1:1 by adjusting the water vapor content of the feed to conditioner. 
     
     
         11 . The method of  claim 1  wherein various sources and types of hydrocarbons are efficiently converted to high quality synthesis gas with a desired molar ratio of H 2 :CO by varying the steam to carbon molar ratio introduced to conditioner without substantial catalyst deactivation and/or coking. 
     
     
         12 . The method of  claim 11  wherein the steam to carbon molar ratio is varied by adjusting steam addition and/or the degree of drying of the carbonaceous feed. 
     
     
         13 . The method of  claim 1  wherein the catalytic heat transfer material has a particle size distribution in the range of from about 100 microns to about 800 microns. 
     
     
         14 . The method of  claim 1  wherein the catalytic heat transfer material comprises an engineered alumina support material, which is from about 10 to about 100 times more attrition resistant than olivine. 
     
     
         15 . The method of  claim 1  wherein the catalytic heat transfer material comprises an engineered alumina support material, which has a hardness of at least about 9.0 on the Mohs scale. 
     
     
         16 . The method of  claim 1  wherein the catalytic heat transfer material comprises an engineered nickel alumina catalyst having a heat capacity of at least about 0.20 cal/gK at 100° C. 
     
     
         17 . The method of  claim 1  wherein the catalytic heat transfer material has a sphericity of greater than about 0.85. 
     
     
         18 . The method of  claim 1  wherein the catalytic heat transfer material comprises a nickel content of from about 1.5 wt % to about 9 wt %. 
     
     
         19 . A system for continuous dry reforming, the system comprising:
 a first dual fluidized bed loop comprising:   a fluid bed conditioner operable to produce a synthesis gas from a gas feed comprising carbon dioxide and at least one selected from methane, ethane, propane, and higher hydrocarbons, wherein the fluid bed conditioner comprises an outlet for a first catalytic heat transfer stream comprising a catalytic heat transfer material and having a first temperature, and an inlet for a second catalytic heat transfer stream comprising catalytic heat transfer material and having a second temperature that is greater than the first temperature;   a fluid bed combustor comprising an inlet fluidly connected with the outlet for a first catalyst stream of the conditioner, and an outlet fluidly connected with the inlet for a second catalytic heat transfer stream of the fluid bed conditioner, and operable to combust fuel and oxidant introduced thereto; and   a catalytic heat transfer material.   
     
     
         20 . The system of  claim 19  wherein the catalytic heat transfer material is selected from the group consisting of nickel olivine, nickel alumina, silica and combinations thereof.