LNG Regasification Power Cycle With Low-Boiling Mixed Working Fluid

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Solution Overview

Problem

Existing ORC systems for LNG regasification face inefficiencies due to the use of non-renewable fuels and high carbon emissions, particularly when operating at room temperature sources, limiting their power generation potential.

Innovation Solution

A process utilizing a mixed working fluid composed of liquefied natural gas (LNG) and liquefied petroleum gas (LPG) (LIMR) to generate power, employing low-temperature heat sources such as sea water or ambient air, and a multi-step heat exchange system to optimize power production without fossil fuels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a high boiling working fluid (IMR) is used in ORC cycle for LNG regasification, then mechanical power extraction from waste heat is maximized, but the expansion ratio is considerably reduced when operating at room temperature sources

Engineering Contradiction:
Improvemechanical power extractionVSAvoidadaptation to low temperature sources
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The patent changes the thermodynamic parameters of the working fluid by using a low boiling fluid instead of the conventional high boiling IMR fluid. This parameter change enables the system to operate effectively at room temperature sources while maintaining adequate expansion ratios for power generation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transitions of a low boiling working fluid that can completely vaporize at room temperature. The fluid undergoes phase change from liquid to vapor in the evaporator using ambient heat sources, then expands through the turbine, and condenses back to liquid in the condenser, enabling continuous cycle operation at low temperatures.

Inventive Principle:
Principle #36Phase transitions

2Productivity

If fossil fuels are used in ORC cycle for continuous power generation, then independent power supply is ensured, but carbon dioxide emissions increase

Engineering Contradiction:
Improvecontinuous power generationVSAvoidcarbon dioxide emissions
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system uses free ambient heat sources (air, water, or ground) to vaporize the working fluid, eliminating the need for fossil fuel combustion. The environment itself provides the thermal energy needed for power generation, making the system self-sufficient and emission-free.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent converts the previously harmful waste heat from LNG regasification into a useful resource for driving the ORC cycle. Instead of dissipating heat to the environment, it is captured and used to vaporize the working fluid, generating electricity while cooling the LNG effluent.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Use of energy by moving object

If IMR fluid is used in ORC cycle, then the formulation exploits frigories in vaporizing LNG stream, but the fluid cannot be completely vaporized at room temperature except at pressures slightly above condensation pressure

Engineering Contradiction:
Improveexploitation of frigoriesVSAvoidpressure constraints
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent changes the fundamental thermodynamic parameters of the working fluid by selecting a low boiling fluid with appropriate vaporization characteristics. This enables complete vaporization at room temperature and atmospheric pressure, eliminating the pressure constraints and complexity associated with IMR fluids.

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

The process achieves efficient power generation at low temperatures using renewable energy sources, reducing carbon emissions and maintaining system simplicity while adapting to low-temperature conditions.

Implementation Method 1

employing low-temperature heat sources such as sea water or ambient air, and a multi-step heat exchange system to optimize power production

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

The choice of a low boiling fluid also allows to reach temperatures lower than the room temperature, with the possibility of achieving a condensing cycle at cryogenic temperatures

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP4189222B1Process for gasifying LNG and for generating power at low temperature
Publication Date: 2025.08.06 SAIPEM SPA
  • EP4189222B1 patent drawingFigure 1
  • EP4189222B1 patent drawingFigure 2
  • EP4189222B1 patent drawingFigure 3

AI summary

The present invention describes a process for gasifying liquefied natural gas (LNG) and for generating power, which operates efficiently at low temperatures.