Char Preparation System and Gasifier for All-Steam Gasification with Carbon Capture

Abstract

An ASG system for polygeneration with CC includes a devolatilizer that pyrolyzes solid fuel to produce char and gases. A burner adds exothermic heat by high-pressure sub-stoichiometric combustion, a mixing pot causes turbulent flow of the gases to heat received solid fuel, and a riser micronizes resulting friable char. A devolatilizer cyclone separates the micronized char by weight providing micronized char, steam and gases to a gasifier feed and oversized char to the mixing pot. An indirect fluid bed gasifier combustion loop includes a gasifier coupled to the gasifier feed, a steam input to provide oxygen for gasification and to facilitate sand-char separation, and an output for providing syngas. A burner provides POC to a mixing pot which provides hot sand with POC to a POC cyclone via a riser, where the POC cyclone separates sand and POC by weight and provides POC and sand for steam-carbon reaction.

1 - 16 . (canceled) 
     
     
         17 . A method of all-steam gasification for polygeneration with carbon capture, the method comprising:
 a) pyrolyzing solid fuel to produce char and gases in a devolatilizer burner containing gases comprising hydrogen, oxygen and steam or gases comprising syngas, steam, and a mixture of oxygen and carbon dioxide by adding exothermic heat to the devolatilizer burner by high-pressure sub-stoichiometric combustion of the gases to eliminate substantially all oxidation of char in the devolatilizer to generate hot gasses;   b) mixing with turbulent flow the generated hot gases with a solid fuel in a devolatilizer mixing pot to form friable char with pyrolysis gas and steam;   c) micronizing the friable char;   d) separating the micronized char by weight;   e) providing sufficiently micronized char, steam and pyrolysis gases to a gasifier;   f) mixing steam in the gasifier to provide oxygen for gasification reactions, to facilitate sand-char separation and to form syngas that is provided to a gasifier output;   g) providing oversized micronized char back to the devolatilizer mixing pot;   h) providing products of combustion to a gasifier mixing pot comprising sand to form hot sand; and   i) transporting the hot sand and products of combustion to an output.   
     
     
         18 . The method of  claim 17  wherein the micronizing the friable char is performed in a riser. 
     
     
         19 . The method of  claim 18  wherein a turbulent flow in the riser is greater than or equal to 100 feet per second. 
     
     
         20 . The method of  claim 17  wherein the micronizing the friable char comprises micronizing the char to a size between 10- to 20-µm. 
     
     
         21 . The method of  claim 17  wherein the separating the micronized char by weight is performed in a cyclone. 
     
     
         22 . The method of  claim 17  wherein the pyrolyzing solid fuel to produce char and gases in the devolatilizer burner comprises preforming high-pressure sub-stoichiometric combustion of received hydrogen, oxygen, and steam. 
     
     
         23 . The method of  claim 17  further comprising superheating gases in a gasifier burner so that circulating char is not oxidized in the gasifier. 
     
     
         24 . The method of  claim 17  further comprising regulating a flow rate of the oversized micronized char into the devolatilizer mixing pot. 
     
     
         25 . The method of  claim 17  further comprising regulating a solids level to the gasifier mixing pot by adding a fluffing gas. 
     
     
         26 . The method of  claim 17  wherein the solid fuel comprises coal. 
     
     
         27 . The method of  claim 17  wherein the solid fuel comprises biomass. 
     
     
         28 . The method of  claim 17  wherein the solid fuel comprises plastic material. 
     
     
         29 . The method of  claim 17  further comprising cooling the syngas. 
     
     
         30 . The method of  claim 29  further comprising cleaning up the cooled syngas. 
     
     
         31 . The method of  claim 30  further comprising performing a water gas shift and steam methane reforming of the cleaned cooled syngas and producing hydrogen for a power block or a solid fuel to liquids system.