Gas Supply Assembly Heat Transfer Circuit

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Solution Overview

Problem

Liquefied gas transport vessels face challenges in providing sufficient propulsion gas due to insufficient natural boil-off gas, requiring additional forced boil-off gas, and existing solutions are inefficient in managing pressure and temperature for gas supply.

Innovation Solution

A gas supply assembly with a heat transfer circuit that includes multiple heat exchangers and a compressor, allowing for efficient preparation and pressure increase of both natural and forced boil-off gases using a single heat source and shared heat transfer medium, with temperature control mechanisms to optimize gas delivery to consumers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a cryogenic compressor is used to increase gas pressure, then the pressure of the gas is raised, but the compressor needs to withhold cryogenic temperatures which is technically very demanding

Engineering Contradiction:
Improvegas pressureVSAvoidtemperature control complexity
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The gas is pre-heated in a heat exchanger before entering the compressor, so the compressor does not need to handle cryogenic temperatures. This preliminary heating action simplifies the compressor's temperature control requirements while still allowing pressure increase to be achieved.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A heat exchanger is introduced as an intermediary component between the heat source and the compressor. This intermediary device transfers thermal energy to the gas before compression, mediating the temperature difference and allowing the compressor to operate at manageable temperatures rather than cryogenic conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If separate heat sources are used for heating gas in different supply lines, then gas preparation can be performed, but the system becomes more complex and less efficient

Engineering Contradiction:
Improvegas preparation efficiencyVSAvoidheat source configuration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Multiple heat exchangers that were previously separate are merged into a single integrated heat exchanger system. This single heat exchanger serves multiple functions: heating gas for the compressor and evaporating liquid gas, thereby reducing the number of separate heat sources needed and improving overall system efficiency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single heat exchanger is designed to perform multiple functions simultaneously - it acts as both a gas heater for the compressor and a liquid gas evaporator. This multi-functionality eliminates the need for separate dedicated heat sources, simplifying the overall system configuration while maintaining or improving productivity.

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

3Quantity of substance

If natural boil-off gas is combined with forced boil-off gas after pressure increase, then gas supply is achieved, but the amount of natural boil-off gas is not sufficient for providing all propulsion energy required

Engineering Contradiction:
Improvegas supply quantityVSAvoidpropulsion energy provision
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The system prepares both natural and forced boil-off gases in advance through the heat exchanger, heating them to appropriate temperatures before they are combined and supplied to consumers. This preliminary preparation ensures that sufficient gas is available and in the correct state to meet propulsion energy requirements.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The heat exchanger changes the temperature parameter of the gases, heating the natural boil-off gas and evaporating the liquid forced boil-off gas to appropriate temperatures for consumption. This parameter change enables the gases to be effectively combined and supplied to meet the energy requirements of propulsion systems.

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

Enhances the performance of gas supply systems by efficiently utilizing both natural and forced boil-off gases, improving pressure and temperature management, and simplifying the installation and operation in marine vessels.

Implementation Method 1

the first heat exchanger configured to evaporate the liquefied gas in the first gas supply line

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

a first heat exchanger configured to evaporate the liquefied gas in the first gas supply line

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

the second heat exchanger configured to heat the gaseous gas in the second gas supply line

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 4

a second heat exchanger configured to heat the gaseous gas in the second gas supply line

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 5

the third heat exchanger configured to cool the compressor

Methodology Applied
Scientific EffectCooling: Cooling

Implementation Method 6

the third heat exchanger configured to cool the compressor

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 7

a fourth heat exchanger configured to transfer heat to heat transfer medium in the heat transfer circuit

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 8

a fourth heat exchanger configured to transfer heat to heat transfer medium in the heat transfer circuit

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 9

a compressor configured to increase the pressure of the gaseous gas in the second supply line

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3769004B1A gas supply assembly
Publication Date: 2022.08.03 WARTSILA FINLAND OY
  • EP3769004B1 patent drawingFigure 1
  • EP3769004B1 patent drawingFigure 2

AI summary

A gas supply assembly (10) comprising a tank configured to store liquefied gas in the tank (12) so as to have an gaseous phase section (12.1) and a liquid phase section (12.2), the assembly further comprising a first gas supply line (18), a second gas supply line (16), wherein the second gas supply line (16) comprises a second heat exchanger (20) configured to heat the gaseous gas in the second gas supply line (16) and the first gas supply line (18) comprises a first heat exchanger (24) configured to evaporate the liquefied gas in the first gas supply line (18), and a compressor (22) configured to increase the pressure of the gaseous gas in the first supply line (16) in which the compressor is provided with a third heat exchanger (28). The assembly (10) comprises a heat transfer circuit (30) to which the second heat exchanger (20), the first heat exchanger (24), the third heat exchanger (26) and a fourth heat exchanger (32) are connected. The second heat exchanger (20) and the third heat exchanger (28) are arranged in series with each other and that the first heat exchanger (24) is arranged in parallel with the second and the third heat exchanger (20, 28).