Cooling method for liquefying a feed gas

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Solution Overview

Problem

Industrial hydrogen liquefaction plants face high operational and capital expenditures due to the use of mechanically or electrically driven compressors for pressure elevation in cooling cycles.

Innovation Solution

A cooling method utilizing an ejector to compress and merge expanded refrigerant streams, eliminating the need for costly compressors by using a fluid jet ejector with a propellant and suction inlet to generate a pumping effect, thereby reducing pressure and increasing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If mechanically or electrically driven compressors are used to raise pressure levels in cooling cycles, then the required pressure elevation is achieved, but operational and capital expenditures increase

Engineering Contradiction:

Improvepressure levelVSAvoidcost expenditure

Core Design Contradiction:

Stress or pressureVSEase of manufacture

Solution Approach 1:

The patent replaces mechanically or electrically driven compressors with a fluid dynamic system using ejectors and pressure exchangers. The ejector uses a high-pressure fluid stream to compress a low-pressure stream through fluid dynamic interactions, eliminating the need for mechanical compression devices and reducing both capital and operational expenditures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs pneumatic and hydraulic principles by using fluid streams under pressure to perform compression work. The pressure exchanger transfers energy between fluid streams through pressure equalization, and the ejector uses a motive fluid to compress the refrigerant stream, replacing mechanical systems with fluid-based solutions.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Reliability

If mechanically or electrically driven compressors are used for pressure elevation, then the cooling cycle operates effectively, but device complexity and maintenance requirements increase

Engineering Contradiction:

Improvecooling cycle operationVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical compression systems with simpler fluid dynamic devices. The ejector has no moving parts and the pressure exchanger uses passive pressure equalization, significantly reducing device complexity and maintenance requirements while maintaining effective cooling cycle operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and eliminates the mechanical compressor component from the cooling cycle, replacing it with fluid-based compression mechanisms. This removal of complex mechanical subsystems simplifies the overall system while maintaining the necessary pressure elevation functions.

Inventive Principle:

Principle #2Taking out (Extraction)

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 method provides a cost-optimized cooling solution by simplifying the design, reducing maintenance costs, and improving operational efficiency in hydrogen liquefaction plants, while maintaining effective cooling for liquefying hydrogen.

Implementation Method 1

guiding the expanded first partial stream to a suction inlet of an ejector and guiding the second partial stream to a propellant inlet of the ejector such that, upon expanding the second partial stream in the ejector, the expanded first partial stream is compressed and merged with the expanded second partial stream

Methodology Applied

Scientific EffectEjector effect: Jet

Implementation Method 2

expanding the first partial stream in a first expansion device and transferring cooling energy from the expanded first partial stream to a feed gas stream to be cooled

Methodology Applied

Scientific EffectGas expansion: Pressure Drop

Implementation Method 3

transferring cooling energy from the expanded first partial stream to a feed gas stream to be cooled

Methodology Applied

Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentUS20210381756A1Cooling method for liquefying a feed gas

Publication Date: 2021.12.09 LINDE AG

AI summary

The present invention pertains to a cooling method for liquefying a feed gas, comprising the steps of providing a cooling cycle with a refrigerant stream; dividing the refrigerant stream into a first partial stream and a second partial stream; expanding the first partial stream in a first expansion device; and transferring cooling energy from the expanded first partial stream to a feed gas stream to be cooled, particularly comprising hydrogen and/or helium. Further the method comprises the steps of guiding the expanded first partial stream to a suction inlet of an ejector; and guiding the second partial stream to a propellant inlet of the ejector such that, upon expanding the second partial stream in the ejector, the expanded first partial stream is compressed and merged with the expanded second partial stream.