Integrated CO2 Capture in Gas Separation Turbines
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Solution Overview
Problem
Current membrane-based CO2 capture processes for gas-fired power plants are limited by the high temperature of the compressed gas streams, which requires expensive inorganic membranes and significant cooling, making the process costly and energy-intensive.
Innovation Solution
Integrating a sweep-based membrane gas separation step between compression stages, allowing carbon dioxide capture at intermediate pressures (2-10 bar) and temperatures (100-200°C), enabling the use of polymeric membranes and reducing the need for extensive cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If membrane-based CO2 capture is applied to gas turbine exhaust, then CO2 separation is achieved, but the high temperature requires expensive inorganic membranes and significant cooling
Solution Approach 1:
The patent applies preliminary cooling to reduce the temperature of combustion gases before they enter the membrane separation unit. By cooling the gases in advance (from typical combustion temperatures of 500-800°C down to 20-100°C), the process enables the use of lower-cost polymeric membranes that cannot withstand high temperatures, thereby resolving the contradiction between separation effectiveness and manufacturing cost.
Solution Approach 2:
The patent changes the temperature parameter of the combustion gas stream to make it compatible with polymeric membranes. By transforming the gas temperature from high (500-800°C) to low (20-100°C), the process enables the use of cost-effective polymeric materials instead of expensive inorganic membranes, while maintaining CO2 separation effectiveness.
2Quantity of substance
If combustion air is used as sweep stream, then CO2 concentration in flue gas is increased, but the process complexity increases
Solution Approach 1:
The patent applies combustion air for dual purposes: first as the oxidizer in the combustion chamber to generate power, and then as the sweep stream in the membrane separation unit to enhance CO2 removal. By making the air serve multiple functions in the process, the patent increases CO2 concentration in the flue gas without adding external complexity, as the same air resource is utilized at different stages.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces energy and cost requirements for CO2 capture, achieving high carbon dioxide enrichment and recovery with lower-cost, more efficient membrane technology, while minimizing heat loss and operational complexity.
Implementation Method 1
passing the first compressed gas stream to a gas separation apparatus adapted to selectively remove carbon dioxide... providing a membrane having a feed side and a permeate side, and being selectively permeable to carbon dioxide over nitrogen and to carbon dioxide over oxygen
Implementation Method 2
passing air, oxygen-enriched air, or oxygen as a sweep stream across the permeate side... Withdrawing from the permeate side a permeate stream comprising oxygen and carbon dioxide
Data Source
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AI summary
Sweep-based gas separation processes are used for reducing carbon dioxide emissions from gas power plants. The invention involves at least two compression steps, a combustion step, a carbon dioxide capture step, a power generation step and a sweep-based membrane separation step. One of the compression steps is used for producing a low-pressure and low-temperature compressed stream treated in the carbon dioxide capture step, thus dispensing with the need to spend large amounts of energy to cool a compressed stream from a typical compressor which produces a high-pressure stream, generally of 20-30 bar or more.