CO₂ Circulating Fluid Power Generation for High Efficiency and Capture

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Solution Overview

Problem

Current power generation methods from fossil fuels face challenges such as rising energy costs, increasing carbon dioxide emissions, and low thermal efficiencies in CO2 capture, making it difficult and costly to reduce carbon emissions effectively.

Innovation Solution

A high efficiency combustor system using a CO2 circulating fluid, which introduces CO2 along with fuel and oxidant for combustion, producing a high-pressure, high-temperature fluid stream that is expanded through a turbine, allowing for efficient power generation while capturing and recycling CO2 for sequestration.

Engineering Contradictions & Design Principles

VSEngineering 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

Engineering Contradiction:
ImproveCO2 emissionVSAvoidthermal efficiency
Core Design Contradiction:
Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The patent changes the operating parameters of the power generation system by using a CO2 circulating fluid at high pressure (greater than 73.8 atm) and high temperature conditions. This allows the system to achieve both CO2 capture and high thermal efficiency (greater than 45% LHV) by operating in a supercritical state where CO2 has enhanced heat transfer properties and the system can directly produce pipeline-quality CO2 for sequestration without additional compression energy penalties

Inventive Principle:
Principle #35Parameter changes

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

Engineering Contradiction:
ImproveCO2 emissionVSAvoidcapital cost
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent creates a multi-functional system where the CO2 circulating fluid serves multiple purposes simultaneously: it acts as a heat transfer medium in the boiler, a working fluid in the turbine for power generation, and the captured CO2 product for sequestration. This eliminates the need for separate CO2 capture equipment, compression systems, and storage infrastructure, thereby reducing capital costs while achieving both power generation and CO2 sequestration goals

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Stress or pressure

If CO2 is captured at high pressure for delivery to sequestration sites, then CO2 can be delivered for sequestration, but present technology provides very low thermal efficiencies

Engineering Contradiction:
ImproveCO2 pressureVSAvoidthermal efficiency
Core Design Contradiction:
Stress or pressureVSLoss of energy

Solution Approach 1:

The patent maintains continuous high pressure conditions throughout the entire system cycle. CO2 is pressurized once at the beginning of the cycle and remains under high pressure through the boiler, turbine, condenser, and back to the boiler. This eliminates the need for additional compression stages that would consume energy, allowing the system to deliver CO2 at pipeline pressure (greater than 73.8 atm) while maintaining thermal efficiency greater than 45% LHV

Inventive Principle:
Principle #20Continuity of useful action

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 achieves high efficiency power production with reduced capital costs, enabling substantial CO2 capture and sequestration at pipeline pressures, exceeding the efficiency of current coal-fired power stations and minimizing atmospheric CO2 release.

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

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

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

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

combusting the fuel to provide a combustion product stream comprising CO2, the combustion product stream having a temperature of at least about 800°C

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3789677A1Method for high efficiency power generation using a carbon dioxide circulating working fluid
Publication Date: 2021.03.10 8 RIVERS CAPITAL LLC
  • EP3789677A1 patent drawingFigure 1
  • EP3789677A1 patent drawingFigure 2
  • EP3789677A1 patent drawingFigure 3A~3B

AI summary

The present invention provides methods and system for expanding a heated and pressurized stream comprising recycled CO2 across at least one turbine so as to generate power and output from the at least one turbine a turbine discharge stream comprising CO2; treating the turbine discharge stream comprising CO2 to form the recycled CO2; compressing the recycled CO2; and heating the compressed, recycled CO2 using at least two different sources of heat prior to passing the recycled CO2 into a combustor.