Integrated gasification combined cycle plant with char preparation system
First Claim
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1. An Integrated Gasification Combined-Cycle (IGCC) gasifier comprising:
- a pressure vessel comprising at least one inlet conduit that receives a supply air, a steam supply, a solid fuel, and pulverized char, and at least one outlet conduit that passes the pulverized char and syngas, the pressure vessel containing an internally-circulating fluidized bed carbonizer comprising a draft tube that receives a stream of the solid fuel surrounded by a two-zone fluidized bed system comprising an upper bed that thermally cracks tars in volatiles, and an annular fluidized bed surrounding the draft tube that carbonizes the solid fuel with fluidizing air and steam, the internally-circulating fluidized bed carbonizer producing a syngas and a char from the solid fuel;
a syngas cooler coupled to an outlet duct of the internally-circulating fluidized bed carbonizer;
a separator coupled to the syngas cooler that separates entrained char from the syngas;
a syngas cleanup system having an input coupled to the at least one outlet conduit of the pressure vessel that removes contaminants from the syngas produced by the internally-circulating fluidized bed carbonizer;
a char preparation system coupled to the separator that prepares the entrained char to be injected into the internally-circulating fluidized bed carbonizer, the char preparation system comprising;
a cooler that removes heat from the char forming a cooled char,a pulverizer coupled to the cooler that pulverizes the cooled char, andan airlock coupled to the pulverizer; and
an injector that receives the pulverized char from the char preparation system along with a stream of air for combustion of the pulverized char and introduces the pulverized char into the draft tube disposed in the internally-circulating fluidized bed carbonizer, whereby the pulverized char burns in the draft tube, thereby improving utilization of the solid fuel.
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Abstract
Provided herein are systems, methods and equipment that include Integrated Gasification Combined-Cycle technology to retrofit existing plants, that include, e.g., subsystems for separating char fines from syngas after it emerges from an internally-circulating fluidized bed carbonizer and injecting the char into the carbonizer draft tube as a fuel source. Efficiency and power generation are thus increased to the extent that inclusion of carbon capture systems are now possible for existing coal plants in order to significantly reduce carbon dioxide emissions.
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Citations
12 Claims
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1. An Integrated Gasification Combined-Cycle (IGCC) gasifier comprising:
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a pressure vessel comprising at least one inlet conduit that receives a supply air, a steam supply, a solid fuel, and pulverized char, and at least one outlet conduit that passes the pulverized char and syngas, the pressure vessel containing an internally-circulating fluidized bed carbonizer comprising a draft tube that receives a stream of the solid fuel surrounded by a two-zone fluidized bed system comprising an upper bed that thermally cracks tars in volatiles, and an annular fluidized bed surrounding the draft tube that carbonizes the solid fuel with fluidizing air and steam, the internally-circulating fluidized bed carbonizer producing a syngas and a char from the solid fuel; a syngas cooler coupled to an outlet duct of the internally-circulating fluidized bed carbonizer; a separator coupled to the syngas cooler that separates entrained char from the syngas; a syngas cleanup system having an input coupled to the at least one outlet conduit of the pressure vessel that removes contaminants from the syngas produced by the internally-circulating fluidized bed carbonizer; a char preparation system coupled to the separator that prepares the entrained char to be injected into the internally-circulating fluidized bed carbonizer, the char preparation system comprising; a cooler that removes heat from the char forming a cooled char, a pulverizer coupled to the cooler that pulverizes the cooled char, and an airlock coupled to the pulverizer; and an injector that receives the pulverized char from the char preparation system along with a stream of air for combustion of the pulverized char and introduces the pulverized char into the draft tube disposed in the internally-circulating fluidized bed carbonizer, whereby the pulverized char burns in the draft tube, thereby improving utilization of the solid fuel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for increasing efficiency of an Integrated Gasification Combined-Cycle (IGCC) subsystem of a powerplant, the method including:
carbonizing a solid fuel by injecting the solid fuel into a pressurized carbonizer comprising a draft tube surrounded by a two-zone fluidized bed system comprising an upper bed that thermally cracks tars in volatiles, and an annular fluidized bed surrounding the draft tube that carbonizes a solid fuel with fluidizing air and steam, thereby producing a syngas stream and a char fines content; separating the char fines content from the syngas stream; cooling the char lines content; pulverizing the char fines content; reducing an ash fines concentration in the char fines content; and injecting the char fines content into the draft tube of the pressurized carbonizer as a fuel used to more efficiently generate the syngas stream and the char fines content and to more completely utilize the solid fuel, wherein the efficiency of the IGCC subsystem is increased by the return of the char fines to the pressurized carbonizer and its use as a fuel therein. - View Dependent Claims (12)
Specification