System and method for liquefaction of natural gas

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Solution Overview

Problem

Conventional thermodynamic processes for producing liquefied natural gas (LNG) are inefficient, costly, and complex, often requiring additional equipment and failing to meet demand, while the storage and transport of natural gas pose challenges as a viable alternative to conventional fuels.

Innovation Solution

A simplified liquefaction system utilizing a single mixed refrigerant and a two-compressor configuration, combined with a heat exchanger and liquid separators, to efficiently produce LNG by reducing the number of components and optimizing refrigerant cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional thermodynamic processes are used for LNG production, then the liquefaction can be achieved, but the system complexity and cost increase due to requiring additional equipment such as multiple compressors and heat exchangers

Engineering Contradiction:
Improvesystem simplicityVSAvoidequipment complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines multiple refrigerant cycles into a single integrated cycle, merging the functions of multiple compressors and heat exchangers into one unified system. This reduces the number of separate equipment components while maintaining the necessary cooling capacity for LNG production, directly addressing the contradiction between manufacturing simplicity and device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single mixed refrigerant system performs multiple functions simultaneously: it provides cooling across different temperature zones, enables phase separation, and facilitates heat exchange in one integrated cycle. This multi-functionality eliminates the need for separate specialized equipment for each function, reducing overall system complexity while maintaining production capability

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

2Productivity

If conventional thermodynamic processes are used for LNG production, then the liquefaction can be achieved, but the production quantity is insufficient to meet increased demand

Engineering Contradiction:
ImproveLNG production quantityVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent optimizes parameters such as refrigerant composition ratios, pressure levels, and temperature profiles to enhance the efficiency of the single mixed refrigerant cycle. By carefully adjusting these parameters, the system achieves higher LNG production quantities without requiring proportional increases in system complexity or additional equipment

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system incorporates dynamic control mechanisms that allow the single mixed refrigerant cycle to adapt to varying production demands. The refrigerant flow rates, compression ratios, and heat exchange parameters can be dynamically adjusted to optimize production quantity in response to demand changes, maintaining high productivity without fixed complex infrastructure

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If conventional thermodynamic processes are used for LNG production, then the liquefaction can be achieved, but the production cost becomes prohibitive

Engineering Contradiction:
Improveproduction costVSAvoidequipment requirements
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

By merging multiple refrigerant cycles into one, the patent eliminates redundant equipment purchases, installation costs, and maintenance expenses. The single mixed refrigerant system requires fewer compressors, smaller heat exchanger areas, and reduced auxiliary equipment, directly lowering both capital expenditure and operational costs while achieving the same liquefaction function

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and eliminates unnecessary intermediate equipment from conventional multi-cycle systems. By using a single integrated mixed refrigerant cycle, the system removes the need for separate cooling stages, intermediate heat exchangers, and multiple compression trains, thereby reducing equipment requirements and associated costs

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

The system reduces costs and energy consumption by minimizing the number of compressors and coolers, enhancing the efficiency and practicality of LNG production.

Implementation Method 1

a heat exchanger and liquid separators

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

cooling the natural gas to a temperature and pressure at which the natural gas condenses to form liquid natural gas

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

circulating one or more refrigerants (e.g., single mixed refrigerants, duel mixed refrigerants, etc.) through a refrigerant cycle

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

the refrigeration to cool and liquefy an essentially water-free feed gas is provided by a single recirculating mixed refrigerant cycle in which refrigeration is provided by the vaporization of two mixed refrigerant streams

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3230669B1System and method for liquefaction of natural gas
Publication Date: 2025.08.20 SIEMENS ENERGY INC
  • EP3230669B1 patent drawingFigure 1
  • EP3230669B1 patent drawingFigure 2
  • EP3230669B1 patent drawingFigure 3

AI summary

A liquefaction system and method for producing liquefied natural gas (LNG) is provided. The liquefaction system may include a heat exchanger to cool natural gas to LNG, a first compressor to compress and combine first and second portions of a single mixed refrigerant from the heat exchanger, a first cooler to cool the single mixed refrigerant from the first compressor to a first liquid phase and a gaseous phase, and a first liquid separator to separate the first liquid phase from the gaseous phase. The liquefaction system may also include a second compressor to compress the gaseous phase, a second cooler to cool the compressed gaseous phase to a second liquid phase and the second portion of the single mixed refrigerant, a second liquid separator to separate the second liquid phase from the second portion of the single mixed refrigerant, and a pump to pressurize the first liquid phase.