Supercritical CO2 Power Cycle for Efficient Carbon Capture
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Solution Overview
Problem
Current power generation methods from fossil fuels face challenges such as rising energy costs and increased carbon dioxide emissions, with low thermal efficiencies in CO2 capture and high capital costs, necessitating a system for high-efficiency power generation with reduced CO2 emissions and improved sequestration.
Innovation Solution
A power generation system using a high-efficiency combustor with a CO2 circulating fluid, where CO2 is introduced with fuel and oxidant for combustion, producing a high-pressure, high-temperature fluid stream that expands through a turbine, allowing for efficient power production and CO2 separation and recycling, with the ability to maintain high pressure during expansion and process the fluid stream for component separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional CO2 capture technology is used, then CO2 can be captured for sequestration, but thermal efficiency is very low and capital costs are high
Solution Approach 1:
The patent changes the operating parameters of the power generation system by using supercritical CO2 as the working fluid and operating the turbine at high pressures (above 7.38 MPa). This parameter change enables the system to achieve both high thermal efficiency (40-60% or higher) and effective CO2 capture, resolving the contradiction between energy efficiency and CO2 emission control.
Solution Approach 2:
The system integrates multiple functions into a single power generation cycle: electricity generation, CO2 capture, and CO2 compression for sequestration. The supercritical CO2 Brayton cycle simultaneously produces power and delivers purified CO2 at pipeline pressures, eliminating the need for separate capture and compression systems and achieving high efficiency while controlling emissions.
2Object-generated harmful factors
If conventional CO2 capture technology is used, then CO2 can be captured, but capital costs are high resulting in significantly higher electricity costs
Solution Approach 1:
The supercritical CO2 Brayton cycle serves multiple purposes simultaneously: power generation, CO2 capture, and CO2 compression. The system produces electricity while delivering purified CO2 at pipeline pressures (7.38-30 MPa) ready for sequestration, eliminating the need for separate capture and compression infrastructure and reducing overall capital costs.
Solution Approach 2:
The system uses the expansion of supercritical CO2 through the turbine to both generate power and compress the CO2 to sequestration pressures. The CO2 is naturally compressed to high pressures during the power generation process itself, eliminating the need for additional high-pressure compression equipment and reducing capital costs.
3Loss of energy
If high pressure is maintained during turbine expansion, then power generation efficiency is improved, but the pressure ratio across the turbine increases
Solution Approach 1:
The patent operates the turbine with a pressure ratio optimized for supercritical CO2, maintaining inlet pressures above 7.38 MPa (the critical pressure of CO2) while controlling the expansion to achieve high efficiency. The system maintains CO2 in the supercritical phase throughout the cycle, allowing efficient power generation without excessive pressure ratios that would compromise system feasibility.
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
The system achieves high-efficiency power production with reduced capital costs, exceeding current coal-fired power station efficiencies, enabling substantial CO2 capture and sequestration at pipeline pressures, and recovering virtually 100% of CO2, while minimizing physical size and construction costs.
Implementation Method 1
the circulating fluid (at least a portion of which may be recycled from the fluid stream) can be passed through the same heat exchanger to heat the circulating fluid prior to introduction into the combustor
Implementation Method 2
The fluid stream can be introduced into a power generation device, such as a turbine
Implementation Method 3
The fluid stream can be introduced into a power generation device, such as a turbine. Advantageously, the fluid stream can be maintained at a relatively high pressure during expansion in the turbine
Implementation Method 4
a high pressure, high temperature fluid stream is produced comprising the circulating fluid and any combustion products
Data Source
AI summary
The present invention provides methods and system for power generation using a high efficiency combustor in combination with a CO2 circulating fluid. The methods and systems advantageously can make use of a low pressure ratio power turbine and an economizer heat exchanger in specific embodiments. Additional low grade heat from an external source can be used to provide part of an amount of heat needed for heating the recycle CO2 circulating fluid. Fuel derived CO2 can be captured and delivered at pipeline pressure. Other impurities can be captured.