IGCC Power Plant with Flue Gas Recirculation and Purge Gas

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This invention presents an improved method and system for operating an Integrated Gasification Combined Cycle (IGCC) power plant. The core innovation lies in using a membrane filter to selectively separate hydrogen from fuel gas (produced from solid fuels like coal), and utilizing exhaust gas from the gas turbine as the flushing gas for the membrane filter. This approach enables more efficient separation and capture of carbon dioxide (CO2) under pressure, simplifying its subsequent liquefaction and storage, while also eliminating the need for external air separation facilities for flushing gas supply.

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• Cleaner electricity generation from coal, biomass, waste, or refinery residues in IGCC power plants.
• Industrial-scale carbon dioxide capture for storage or utilization in enhanced oil recovery or chemical synthesis.
• Supplying high-purity hydrogen for power generation in gas turbines, fuel cells, or industrial processes.
• Retrofitting or upgrading existing IGCC facilities to improve CO2 capture efficiency and reduce emissions.

BenefitsContent extracted from patent full text and abstract with AI.

• Enables highly efficient CO2 capture before combustion, reducing greenhouse gas emissions.
• Simplifies CO2 conditioning and liquefaction due to high CO2 concentration and pressure in the exhaust.
• Improves overall power plant efficiency by reducing energy losses associated with CO2 separation.
• Eliminates need for external air separation units for flushing gas, lowering operational complexity and costs.
• Facilitates integration and scaling for hydrogen production, contributing to energy transition and decarbonization.

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Patent Abstract

The invention relates to a method for operating an IGCC power plant, wherein a solid fuel, vapor and oxygen are fed to a gasifier, the fuel gas, comprising CO and hydrogen, is fed from the gasifier to at least one shift stage, where a conversion of the CO with water vapor primarily into CO2 and hydrogen is carried out, and the fuel gas is subjected to at least one gas scrubbing step, wherein the gas scrubbing step or steps can be provided before, behind, or between individual shift stages. The hydrogen and CO2-containing fuel gas is conducted across a membrane filter, which selectively separates the hydrogen from the fuel gas at least partially. In order to achieve driving potential in the membrane, a flushing gas is used on the side of the retentate. The fuel gas depleted with hydrogen is fed to a CO2 conditioning process, while the separated hydrogen is fed to a gas turbine, together with the flushing gas. According to the invention, the flushing gas used for the membrane filter is part of the waste gas produced in the gas turbine. The IGCC power plant according to the invention suited for carrying out the method therefore comprises a gasifier for the gasification of a solid fuel, a means for providing oxygen for the gasifier, at least one shift stage provided downstream of the gasifier for converting CO and water vapor into CO2 and hydrogen, at least one gas scrubbing stage provided downstream of the gasifier, a membrane filter provided downstream of the gasifier and having a hydrogen-selective membrane, a means for providing flushing gas for the permeate side of the membrane filter, and a gas turbine, wherein a line leads from the permeate side of the membrane filter to the combustion chamber of the gas turbine, and the means for providing the flushing gas is the combustion chamber of the gas turbine, and a further line is disposed from the combustion chamber to the permeate side of the membrane filter.