Supercritical CO2 Power Generation System Design
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Solution Overview
Problem
Conventional thermal power generation systems face inefficiencies due to phase changes in working fluids, leading to energy loss and complex system designs, particularly in steam power generation where phase changes are necessary for energy transfer, resulting in reduced turbine efficiency and complicated gas-water separation processes.
Innovation Solution
A direct-fired supercritical CO2 power generation system uses supercritical CO2 as a working fluid that does not undergo phase change, employing a closed loop cycle with a furnace, turbine, recuperator, cooler, and compressors to preheat combustion air and recover heat from exhaust gas, simplifying the system and enhancing heat exchange efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If steam power generation uses phase change of water as working fluid, then heat exchange between heat source and working fluid can occur, but turbine efficiency is reduced due to moisture loss and the system becomes complicated
Solution Approach 1:
The patent changes the working fluid from water/steam to supercritical CO2, altering the thermodynamic parameters. Supercritical CO2 operates above its critical point (31°C, 73 atm) where distinct liquid and gas phases do not exist, eliminating phase change while maintaining efficient heat transfer properties. This parameter change resolves the contradiction by removing moisture-related turbine losses and simplifying the system without compromising heat exchange capability.
Solution Approach 2:
The patent converts the typically harmful moisture in steam turbines into a benefit by using CO2's unique supercritical state. Instead of dealing with two-phase flow complications and moisture erosion, the system utilizes CO2's single-phase supercritical state to achieve both efficient heat absorption and high turbine efficiency, turning the phase change problem into an advantage.
2Temperature
If a drum is installed in direct-fired heater for gas-water separation, then water supply temperature can be increased, but the system and constituent devices become complicated in design
Solution Approach 1:
The patent extracts and removes the drum component from the system by eliminating the need for gas-water separation. Since supercritical CO2 does not undergo phase change like water, there is no separation process required, and the drum is completely taken out of the system, simplifying the design while maintaining the ability to supply heated fluid at required temperatures.
3Productivity
If steam is extracted from turbine to increase water supply temperature, then overall system efficiency can be enhanced, but the system design becomes complicated
Solution Approach 1:
The patent applies multi-functionality to the supercritical CO2 cycle where the same working fluid performs multiple functions: it absorbs heat in the boiler, expands in the turbine to generate power, and provides heating capability without requiring separate extraction systems. The CO2 circulates through the entire system performing thermal energy transfer and mechanical work in a unified cycle, enhancing efficiency while simplifying design.
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 improves power generation efficiency by eliminating phase change-related energy losses and simplifying system design, allowing for higher heat exchange efficiency and reduced system complexity, with all heat quantities used to increase the working fluid's temperature, thereby enhancing overall system performance.
Implementation Method 1
a furnace to burn fuel
Implementation Method 2
a recuperator exchanging heat with the working fluid passing through the turbine
Implementation Method 3
a cooler to cool the working fluid passing through the recuperator
Implementation Method 4
a compressor to compress the working fluid passing through the cooler
Implementation Method 5
a turbine operated by a working fluid supplied thereto, the working fluid being heated by heat generated in the furnace
Data Source
AI summary
A CO2 power generation system includes a furnace to burn fuel, a turbine operated by a working fluid supplied thereto, the working fluid being heated by heat generated in the furnace, a recuperator exchanging heat with the working fluid passing through the turbine, a cooler to cool the working fluid passing through the recuperator, and a compressor to compress the working fluid passing through the cooler, wherein the working fluid passing through the compressor is circulated to the furnace, and the working fluid is supercritical CO2.