CO2 Circulating Power Cycle for Efficient Carbon Capture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current power generation methods from fossil fuels face challenges with rising energy costs and increasing carbon dioxide emissions, necessitating high efficiency systems that can reduce CO2 emissions and facilitate easy sequestration, while existing technologies struggle with low thermal efficiencies and high capital costs for CO2 capture.
Innovation Solution
A system utilizing 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 generation and CO2 separation and recycling, with the ability to maintain a high pressure ratio and separate components for sequestration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional CO2 capture technology is used, then CO2 can be captured for delivery to sequestration sites, 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 a CO2 circulating fluid at high pressure (maintained throughout the system) and high temperature (achieved through efficient combustors). This transforms the thermodynamic cycle to achieve thermal efficiencies exceeding 50%, compared to the very low thermal efficiencies of conventional CO2 capture technologies. The parameter changes in pressure, temperature, and fluid circulation enable both high efficiency power generation and complete CO2 capture.
Solution Approach 2:
The system implements continuous CO2 circulation through the power generation cycle, where CO2 is continuously captured, pressurized, heated, expanded through a turbine to generate power, then condensed and recycled back to the combustor. This continuous circulation eliminates the need for separate CO2 capture processes and enables simultaneous power generation and complete CO2 capture, resolving the contradiction between energy efficiency and CO2 emission control.
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 patent merges the CO2 capture function with the power generation process itself. The CO2 circulating fluid serves dual purposes: as the working fluid for power generation and as the medium for complete CO2 capture. This consolidation eliminates the need for separate, complex CO2 capture infrastructure and reduces capital costs while achieving both power generation and complete CO2 capture.
Solution Approach 2:
The CO2 circulating fluid performs multiple functions simultaneously: it acts as the working fluid in the power generation cycle, serves as the cooling medium in heat exchangers, functions as the transport medium for complete CO2 capture, and enables high efficiency combustion. This multi-functionality reduces system complexity and capital costs while achieving the dual objectives of power generation and CO2 emission control.
3Stress or pressure
If high pressure is maintained during turbine expansion, then pressure ratio across the turbine is reduced, but this may affect power generation efficiency
Solution Approach 1:
The patent optimizes the pressure ratio parameter by maintaining high absolute pressure throughout the system while reducing the pressure ratio across the turbine to less than 12:1. This parameter optimization, combined with high inlet temperature and efficient heat exchangers, achieves thermal efficiencies exceeding 50%. The system demonstrates that lower pressure ratios can be compensated by other parameter optimizations to maintain or improve overall efficiency.
4Object-generated harmful factors
If the system produces substantially pure CO2 at pipeline pressure, then CO2 can be easily sequestered, but this requires advanced separation and compression capabilities
Solution Approach 1:
The system continuously circulates CO2 through the power generation cycle, maintaining it in a controlled state throughout. The CO2 is continuously captured, pressurized to pipeline pressure, and condensed to high purity in the heat exchangers. This continuous process integrates separation and compression functions into the normal operation, eliminating the need for separate, complex purification and compression facilities.
Solution Approach 2:
The CO2 circulating fluid serves itself through the cycle: it is automatically pressurized by the system pumps, purified through condensation in heat exchangers where impurities are separated, and recycled back to the combustor. The system's own operation provides the separation and compression functions needed to produce pipeline-ready CO2, reducing external infrastructure requirements.
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 generation with reduced capital costs, producing substantially pure CO2 at pipeline pressure for sequestration, exceeding the efficiency of current coal-fired power stations and enabling the recovery of virtually 100% of CO2, while minimizing physical size and capital 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
high efficiency combustion of a fuel
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.