Supercritical CO2 Compression Using Cooling and Liquid Pumping

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Solution Overview

Problem

Existing gas compressing systems require high-power external refrigeration and inefficient operation due to the need for ultra-high pressure after-coolers and compressors, which increases energy consumption and reduces reliability when compressing carbon dioxide for storage.

Innovation Solution

A compressing system that includes a compression section to generate an intermediate supercritical fluid, a cooling section to cool this fluid to near critical temperature, a pumping section to further compress it to target pressure, and a heating section to achieve the desired supercritical state, eliminating the need for high-pressure after-coolers and reducing power requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a compressor is used on the rear-stage side to compress gas to high pressure, then the target pressure can be achieved, but high-pressure gas seals and compressor casings are required, increasing device complexity and cost

Engineering Contradiction:
Improvetarget pressureVSAvoidhigh-pressure gas seals and compressor casings
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The invention changes the physical state parameter of the fluid from gas to liquid by cooling it to near critical temperature before the rear-stage compression. This parameter change allows the use of a pump instead of a high-pressure compressor, eliminating the need for complex high-pressure gas seals and casings while achieving the same target pressure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention transitions from gas compression (pneumatics) to liquid pumping (hydraulics) by cooling the supercritical fluid to near critical temperature. The pump then compresses the liquid state fluid to target pressure, avoiding the complexity of high-pressure gas handling equipment.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Temperature

If carbon dioxide is cooled to near critical temperature at low pressure, then liquefaction occurs, but the amount of refrigeration required becomes greatly enlarged, increasing power consumption

Engineering Contradiction:
Improvenear critical temperatureVSAvoidrefrigeration power
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The invention performs preliminary compression to intermediate pressure (at or above critical pressure) before cooling. This preliminary compression action raises the pressure of the supercritical fluid to a level where subsequent cooling to near critical temperature requires significantly less refrigeration power, as the fluid is already in a dense supercritical state.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the pressure parameter before cooling, raising it to intermediate pressure (at or above critical pressure) through the compression section. This parameter change fundamentally alters the thermodynamic state, reducing the refrigeration power needed to achieve near critical temperature compared to cooling at low pressure.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If an after-cooler with ultra-high pressure and large capacity is used, then carbon dioxide of target temperature and pressure can be obtained, but the operation efficiency and reliability of the overall compressing system fall

Engineering Contradiction:
Improvetarget temperatureVSAvoidoperation efficiency and reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The invention segments the compression and cooling process into distinct sections: a compression section that raises pressure to intermediate levels, and a cooling section that cools to near critical temperature. This segmentation allows each component to operate at optimized pressure levels, avoiding the need for ultra-high pressure after-coolers and improving overall system reliability and efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the thermodynamic parameters along the process path by first compressing to intermediate pressure (at or above critical pressure) and then cooling to near critical temperature. This parameter change sequence eliminates the need for ultra-high pressure after-coolers, improving operation efficiency and reliability while achieving the desired target state.

Inventive Principle:
Principle #35Parameter changes

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 configuration reduces power consumption and improves operational efficiency by minimizing the heat required for cooling and eliminating the need for high-pressure countermeasures, leading to cost savings and enhanced reliability.

Implementation Method 1

a compression section (2) that compresses the target gas to an intermediate pressure, which is equal to or higher than a critical pressure and is lower than the target pressure to generate an intermediate supercritical fluid

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

a cooling section (4) that cools the intermediate supercritical fluid generated in the compression section to near a critical temperature to generate an intermediate supercritical pressure liquid

Methodology Applied
Scientific EffectCooling: Cooling

Implementation Method 3

a pumping section (3) that compresses the intermediate supercritical pressure liquid generated in the cooling section to a pressure that is equal to or higher than the target pressure

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

a heating section (5) that heats the intermediate supercritical pressure liquid compressed in the pumping section to near the critical temperature

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 5

The cooling section has a main cooling part that performs heat exchange with the heating section to cool the intermediate supercritical fluid

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP2896453B1Compressing system, and gas compressing method
Publication Date: 2018.11.07 MITSUBISHI HEAVY INDUSTIES COMPRESSOR CORP
  • EP2896453B1 patent drawingFigure 1
  • EP2896453B1 patent drawingFigure 2
  • EP2896453B1 patent drawingFigure 3

AI summary

A compressing system that compresses a target gas to a pressure that is equal to or higher than a target pressure higher than a critical pressure. The compressing system includes a compression section that compresses the target gas to an intermediate pressure, which is equal to or higher than the critical pressure and is lower than the target pressure to generate an intermediate supercritical fluid; a cooling section that cools the intermediate supercritical fluid generated in the compression section to near a critical temperature to generate an intermediate supercritical pressure liquid; and a pumping section that compresses the intermediate supercritical pressure liquid generated in the cooling section to a pressure that is equal to or higher than the target pressure. At least one of the intermediate supercritical pressure liquid compressed in the pumping section, a low-temperature liquid generated by extracting the intermediate supercritical pressure liquid on the upstream side of the pumping section to reduce pressure to near the critical pressure, and an external cooling medium is used as a cooling medium in the cooling section.