Double Shell Tank Adsorbent Cooling via Metal Sheet

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Solution Overview

Problem

Conventional double-shell tanks face high costs due to the need for melt-fusing adsorbents to thermal insulation films and inadequate cooling of adsorbents, leading to suboptimal gas adsorption ability and thermal stratification issues within the tank.

Innovation Solution

A double-shell tank design featuring a metal sheet mounted to the inner shell with adsorbents placed on it, covered by thermal insulation sheets that do not contact the outer shell, allowing for efficient cooling of the adsorbents to the inner shell's temperature without the need for melt-fusion, thus reducing costs and enhancing adsorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the adsorbent is interposed between the thermal insulation films, then the adsorbent is protected from direct cooling, but the adsorbent's adsorption ability is insufficient due to inadequate cooling

Engineering Contradiction:
Improvevacuum retentionVSAvoidadsorbent temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

A metal sheet is introduced as an intermediary thermal conduction member between the inner shell and the adsorbent. The metal sheet has high thermal conductivity and is in direct contact with both the inner shell and the adsorbent, serving as a mediator to efficiently transfer cold from the inner shell to the adsorbent, solving the problem of insufficient cooling while maintaining protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal insulation structure is segmented into multiple layers: the inner shell, metal sheet, adsorbent layer, and thermal insulation films. This segmentation allows the adsorbent to be positioned in a specific zone where it receives controlled cooling through the metal sheet while being protected from direct contact with the cryogenic environment by the insulation films.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the adsorbent is melt-fused to the thermal insulation films, then the adsorbent is securely positioned, but the manufacturing cost increases significantly

Engineering Contradiction:
Improveadsorbent positioningVSAvoidmanufacturing cost
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The metal sheet serves as a support structure and thermal conduit that simplifies the overall assembly process. Instead of requiring complex melt-fusion operations to attach adsorbent to insulation films, the adsorbent is placed on the metal sheet which is already securely mounted to the inner shell, reducing manufacturing complexity and cost.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The metal sheet provides localized structural support and thermal conduction exactly where needed - at the interface between the inner shell and adsorbent. This localized approach eliminates the need for expensive melt-fusion processes across the entire insulation structure, reducing overall manufacturing cost while maintaining adsorbent positioning stability.

Inventive Principle:
Principle #3Local quality

3Temperature

If the adsorbent is brought into close contact with the bottom surface of the inner shell, then the adsorbent is cooled to the lowest temperature, but gravitational force causes the adsorbent to detach

Engineering Contradiction:
Improveadsorbent temperatureVSAvoidgravitational force on adsorbent
Core Design Contradiction:
TemperatureVSForce

Solution Approach 1:

The metal sheet acts as a mediator that is firmly attached to the bottom surface of the inner shell and provides a supported platform for the adsorbent. This intermediary structure transfers the mechanical support function from the adsorbent-to-shell contact to the metal sheet, allowing the adsorbent to be cooled effectively while preventing detachment due to gravity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The metal sheet can be designed as a thin, flexible yet structurally sound component that conforms to the inner shell's bottom surface and provides adequate support for the adsorbent layer. This thin-film approach maintains thermal efficiency while providing the necessary mechanical support to counteract gravitational forces.

Inventive Principle:
Principle #30Flexible shells and thin films

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 solution effectively cools adsorbents to the inner shell's temperature, improving gas adsorption ability while maintaining structural integrity and reducing costs, thereby enhancing the vacuum retention capacity of the tank.

Implementation Method 1

the adsorbent adsorbs gas molecules by physisorption

Methodology Applied
Scientific EffectPhysisorption: Physisorption

Implementation Method 2

gas molecules are concentrated on a fixed surface (the adsorbent) by van der Waals force

Methodology Applied
Scientific Effectvan der Waals force: Van der Waals Force

Implementation Method 3

a thermal insulator covering the inner shell and the metal sheet

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 4

a vacuum space is formed between the inner shell and the outer shell

Methodology Applied
Scientific EffectVacuum insulation: Vacuum

Data Source

PatentEP3699476B1Double shell tank and ship
Publication Date: 2023.11.29 KAWASAKI JUKOGYO KK
  • EP3699476B1 patent drawingFigure 1
  • EP3699476B1 patent drawingFigure 2
  • EP3699476B1 patent drawingFigure 3

AI summary

A double-shell tank includes: an inner shell storing liquefied gas; an outer shell surrounding the inner shell, the outer shell forming a vacuum space between the inner shell and the outer shell; at least one metal sheet mounted to the inner shell, such that the metal sheet faces at least a bottom surface of the inner shell; an adsorbent placed on the metal sheet, the adsorbent adsorbing gas molecules by physisorption; and a thermal insulator covering the inner shell over the metal sheet.