Cryogenic Tank Insulation with Metallic Vapour Barrier
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Solution Overview
Problem
Existing insulation systems for cryogenic liquid tanks, such as LNG tanks, face challenges in maintaining thermal efficiency and integrity over time due to humidity ingress and gas diffusion, leading to foam degradation and reduced insulation performance.
Innovation Solution
A multi-layered insulation system comprising a foam layer encapsulated by a gas-tight metallic vapour barrier, with varying densities and optional fire retardant and cladding layers, prevents humidity and gas diffusion, enhancing thermal performance and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sprayed foam insulation is applied to the outside of the LNG tank, then the insulation is cost effective and easy to apply, but the foam layer is susceptible to humidity ingress and gas diffusion leading to degradation
Solution Approach 1:
The patent combines spray foam insulation with a metallic vapour barrier to create a composite insulation system. The spray foam provides thermal insulation while the metallic vapour barrier prevents humidity ingress and gas diffusion, protecting the foam from degradation. This composite structure resolves the contradiction by maintaining the ease of application of spray foam while adding the protective function of the vapour barrier to ensure long-term reliability.
Solution Approach 2:
The patent uses a thin metallic vapour barrier film to encapsulate the spray foam insulation. This thin film provides a protective barrier against humidity and gas diffusion without adding significant complexity to the application process. The flexible nature of the thin film allows it to conform to the tank surface and foam layer, maintaining the simplicity of the overall insulation system while significantly improving its reliability.
2Ease of manufacture
If a single layer of spray foam is applied, then the application process is simple and cost effective, but the operational life is limited due to foam degradation
Solution Approach 1:
The patent creates a composite insulation system combining spray foam with a metallic vapour barrier. This composite structure maintains the application simplicity and cost-effectiveness of spray foam while dramatically extending the service life by preventing the foam degradation that would otherwise occur due to humidity ingress and gas diffusion.
Solution Approach 2:
The metallic vapour barrier is applied as a preliminary protective layer to encapsulate the spray foam insulation. This preliminary action of sealing the foam within the vapour barrier prevents future degradation, thereby extending the operational life of the insulation system without complicating the overall application process.
3Quantity of substance
If conventional insulation systems are used, then the initial cost is lower, but thermal efficiency is reduced over time due to foam degradation
Solution Approach 1:
The patent employs a composite insulation system with spray foam and metallic vapour barrier. While the initial cost is slightly higher than conventional single-layer foam, the vapour barrier prevents foam degradation, thereby maintaining thermal efficiency over the long term and reducing energy losses that would occur with degraded insulation.
Solution Approach 2:
The patent adds the metallic vapour barrier as an additional protective layer beyond conventional insulation systems. This partial addition provides the necessary protection against humidity and gas diffusion to maintain thermal efficiency, representing a cost-effective enhancement that prevents future energy losses without requiring complete system redesign.
4Reliability
If multiple layers with different densities are applied, then the insulation performance is enhanced, but the manufacturing complexity increases
Solution Approach 1:
The patent uses a composite structure with spray foam and metallic vapour barrier, where each material performs its specific function optimally. The spray foam provides thermal insulation while the metallic vapour barrier provides moisture and gas protection. This functional differentiation enhances insulation performance without requiring complex multi-density foam layering, thereby managing manufacturing complexity.
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 significantly prolongs the operational life of the insulation by preventing foam degradation, maintaining thermal efficiency, and providing enhanced mechanical strength and fire protection for cryogenic liquid tanks.
Implementation Method 1
a gas-tight metallic vapour barrier, prevents humidity and gas diffusion
Implementation Method 2
prevents humidity and gas diffusion, enhancing thermal performance
Implementation Method 3
A multi-layered insulation system comprising a foam layer encapsulated by a gas-tight metallic vapour barrier
Data Source
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AI summary
The present invention is concerned with a cryogenic insulation system for ocean going vessels. The method and system involve the steps of sequentially applying a plurality of layers to the outer surface of the tank. The layers include a first foam layer applied to the tank, a second gas/liquid impervious coating applied to the first layer and an outer cladding layer applied to the second layer.