Cryogenic Tank Multi-Layer Structure Mass Reduction

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Solution Overview

Problem

Existing storage tanks for cryogenic fluids, such as liquefied carbon dioxide, face issues with high cost, large mass, chemical incompatibility, insufficient sealing, mechanical resistance, and thermal insulation, particularly in semi-trailer type vehicles using single-walled tanks without vacuum insulation.

Innovation Solution

A multi-layered tank structure comprising a waterproof metallic layer, a laminated carbon or glass fiber layer, a thick thermal insulation layer, and an outer laminated layer, using materials like expanded polystyrene, polyurethane, and vacuum-insulated panels, with a specific thickness distribution to ensure mechanical strength, thermal insulation, and chemical compatibility, while reducing mass and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a single-walled cryogenic tank made of fine-grained carbon steel with polyurethane insulation is used, then mechanical resistance and chemical compatibility are ensured, but the tank mass and cost increase significantly

Engineering Contradiction:
Improvemechanical resistanceVSAvoidtank mass
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by combining carbon fiber reinforced polymer (CFRP) layers with stainless steel liners and vacuum insulation. The CFRP provides mechanical strength while being lighter than carbon steel, and the vacuum insulation eliminates the need for heavy polyurethane insulation layers, thereby reducing overall tank mass while maintaining mechanical resistance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The tank wall is segmented into multiple functional layers: an inner stainless steel liner for chemical compatibility, intermediate CFRP layers for mechanical strength, and a vacuum space for thermal insulation. This segmentation allows each layer to optimize its specific function while collectively reducing the total mass compared to a monolithic carbon steel construction.

Inventive Principle:
Principle #1Segmentation

2Loss of energy

If a single-walled cryogenic tank with polyurethane insulation is used, then thermal insulation is provided, but the tank mass and cost increase

Engineering Contradiction:
Improvethermal insulationVSAvoidtank mass
Core Design Contradiction:
Loss of energyVSWeight of moving object

Solution Approach 1:

The patent extracts the insulation medium (polyurethane foam) from the tank wall structure and replaces it with a vacuum space. By removing the thermal conduction path through the wall, vacuum insulation provides superior thermal insulation performance without the mass penalty of thick polyurethane layers, directly addressing the contradiction between insulation effectiveness and tank mass.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The combination of CFRP structural layers with vacuum insulation creates a composite wall structure that achieves both mechanical strength and thermal insulation. The CFRP layers provide structural integrity while the vacuum provides thermal isolation, eliminating the need for heavy polyurethane insulation and reducing overall tank mass.

Inventive Principle:
Principle #40Composite materials

3Reliability

If fine-grained carbon steel is used for the tank wall, then mechanical resistance and chemical compatibility are ensured, but the tank cost increases

Engineering Contradiction:
Improvechemical compatibilityVSAvoidtank cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a composite structure where a thin stainless steel liner (0.5-2mm) provides chemical compatibility with cryogenic fluids, while the primary structural load-bearing function is transferred to the external CFRP layers. This allows reduction of the expensive stainless steel thickness while maintaining chemical compatibility, thereby reducing overall tank cost.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The stainless steel liner is applied only as a thin inner layer where chemical compatibility is required, rather than using thick carbon steel throughout the entire wall structure. The CFRP layers provide the bulk of the mechanical strength, allowing optimization of material placement according to specific functional requirements and reducing overall material cost.

Inventive Principle:
Principle #3Local quality

4Weight of moving object

If a multi-layered structure with vacuum insulation is used, then thermal insulation and mass reduction are achieved, but the structure becomes more complex

Engineering Contradiction:
Improvetank massVSAvoidwall structure complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The tank wall is divided into distinct functional segments: an inner stainless steel liner, intermediate CFRP layers, and a vacuum space. This segmentation allows each layer to be optimized independently for its specific function (chemical compatibility, mechanical strength, thermal insulation) while simplifying the design and manufacturing process compared to attempting a monolithic structure.

Inventive Principle:
Principle #1Segmentation

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 multi-layered structure provides effective thermal insulation, mechanical resistance, and chemical compatibility with cryogenic fluids, significantly reducing the tank's mass and cost compared to traditional fine-grained carbon steel tanks, while maintaining structural integrity and efficiency in transporting cryogenic fluids.

Implementation Method 1

the tank being devoid of vacuum insulation

Methodology Applied
Scientific EffectVacuum insulation: Vacuum

Implementation Method 2

a third layer comprising a thickness of thermal insulation

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

a second layer comprising a thickness of laminated material based on carbon fibers and/or glass fibres, a fourth layer comprising a thickness of laminated material based on carbon fibers and/or fiberglass

Methodology Applied
Scientific EffectLamination: Lamination

Data Source

PatentEP2942556B1Storage tank for a cryogenic fluid and trailer comprising such a tank
Publication Date: 2019.09.04 CRYOLOR
  • EP2942556B1 patent drawingFigure 1~4
  • EP2942556B1 patent drawingFigure 5~6

AI summary

Cryogenic fluid storage tank without vacuum insulation and comprising a wall (3) comprising a multilayer structure including, from the inside of the tank (1) to the outside of the tank (1): - a first sealed layer (13) comprising one of: a resin reinforced with glass fibers and/or carbon fibers, a polymer such as polyurethane, aluminum, steel, stainless steel, - a second layer (23) comprising a thickness of laminated material based on carbon fibers and/or glass fibers, - a third layer (33) comprising a thickness of thermal insulation, - a fourth layer (43) comprising a thickness of laminated material based on carbon fibers and/or glass fibers, the first layer (13) having a thickness of between 0.1 mm and 6 mm, the second layer (23) having a thickness of between 5 and 40 mm, the third layer (33) having a thickness of between 20 and 200 mm,the fourth layer (43) having a thickness between 2 and 20mm.