System and method for high efficiency power generation using a carbon dioxide circulating working fluid
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power generation methods using fossil fuels face challenges with rising energy costs and increased carbon dioxide emissions, necessitating high efficiency systems that can reduce CO2 emissions and facilitate CO2 sequestration while avoiding atmospheric release.
Innovation Solution
A power generation 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 production and CO2 separation and recycling, with the ability to maintain a low pressure ratio and separate CO2 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 transcritical CO2 cycle instead of conventional steam cycles. The CO2 is operated at pressures above its critical point (7.38 MPa) with specific temperature-pressure relationships that optimize both power generation efficiency and CO2 capture. The heat exchanger is designed to maintain a small temperature difference (less than 50°C) between turbine exhaust and recycle CO2, improving thermal efficiency while capturing CO2 at pipeline pressure.
Solution Approach 2:
The CO2 circulating fluid serves multiple functions simultaneously: it acts as the working fluid for power generation in the transcritical cycle, serves as the captured CO2 product for sequestration delivery, and is recycled back to the combustor. This multi-functionality eliminates the need for separate CO2 capture systems, achieving both power generation and CO2 capture with high thermal efficiency.
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 CO2 circulating fluid serves multiple functions simultaneously: it acts as the working fluid for power generation in the transcritical cycle, serves as the captured CO2 product for sequestration delivery, and is recycled back to the combustor. This multi-functionality eliminates the need for separate CO2 capture systems, achieving both power generation and CO2 capture with high thermal efficiency.
Solution Approach 2:
Instead of discarding CO2 as a waste product requiring separate capture infrastructure, the system recovers CO2 as a valuable circulating fluid that drives the power generation cycle. The CO2 is continuously recovered from combustion products, purified, and recycled, transforming a waste disposal problem into a resource utilization solution that reduces capital costs.
3Productivity
If high pressure ratio is used in turbine expansion, then power generation efficiency improves, but CO2 separation and sequestration becomes more difficult
Solution Approach 1:
The patent optimizes the pressure ratio across the turbine to balance power generation efficiency with CO2 separation requirements. By operating at a moderate pressure ratio (less than about 12) and maintaining the CO2 in a supercritical state, the system achieves efficient expansion while keeping the CO2 partial pressure high enough for effective separation and delivery to sequestration sites at pipeline pressure.
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, and enables the recovery of nearly 100% of CO2 at pipeline pressure for sequestration, while minimizing physical size and capital expenditures.
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
combustion of a fuel and/or suitable biomass
Implementation Method 5
a high efficiency combustor (e.g., a transpiration cooled combustor)
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.