Cold Flexible Polyurethane Insulation for LNG Retrofitting
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Solution Overview
Problem
Current insulation methods for liquefied natural gas tanks, such as those using rigid polyurethane foams, are complex and not suitable for retrofitting due to space constraints, and they do not provide adequate cryogenic thermal stress resistance and flexibility at low temperatures.
Innovation Solution
A process for producing cold-flexible polyurethane insulation by mixing polyisocyanates with reactive compounds, blowing agents, catalysts, plasticizers, and additives, where the isocyanate index is between 100-200, and specific polyetherols and polyesterols are used to achieve a high CTSR factor and improved mechanical properties at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid polyurethane foam insulation boards are used for LNG tanks, then thermal insulation performance is achieved, but the installation complexity increases and retrofitting becomes difficult
Solution Approach 1:
The rigid polyurethane foam is divided into separate insulation boards that can be individually handled and installed. These boards are then adhesively bonded together to form the complete insulation layer, simplifying the installation process while maintaining thermal insulation performance
Solution Approach 2:
The patent combines multiple functions into the insulation system: thermal insulation, structural support with plywood sheets, and reinforcement with resin-impregnated glass fiber mats, creating an integrated solution that addresses both insulation requirements and installation practicality
2Ease of manufacture
If conventional polyurethane formulations are used, then ease of manufacture is maintained, but cryogenic thermal stress resistance and low-temperature flexibility are insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyurethane formulation by incorporating specific polyetherols with defined functionalities and OH numbers, polyesterols, and chain extenders/crosslinkers in controlled amounts, achieving enhanced cryogenic thermal stress resistance while maintaining manufacturing simplicity through a standardized formulation process
Solution Approach 2:
The invention creates a composite polyurethane system combining multiple polyol components (polyetherols and polyesterols) with polyisocyanates, blowing agents, catalysts, and plasticizers to achieve superior cryogenic performance while retaining ease of manufacture through integrated formulation
3Reliability
If insulation boards are cut and adhesively bonded for LNG tank insulation, then thermal insulation is provided, but space requirements increase making retrofitting impossible
Solution Approach 1:
The patent merges the insulation boards with reinforcing elements (plywood sheets and resin-impregnated glass fiber mats) into an integrated composite structure, optimizing space utilization in LNG tanks while maintaining thermal insulation performance
Solution Approach 2:
The use of thin adhesive layers to bond insulation boards creates a compact, space-efficient insulation system that can be fitted into confined LNG tank spaces, enabling retrofitting applications where space is at a premium
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 resulting polyurethane insulation exhibits excellent cryogenic thermal stress resistance, flexibility, and mechanical properties, making it suitable for insulating liquefied natural gas tanks, particularly in confined spaces like those on board ships, with a CTSR factor of at least 1.2 and thermal conductivity of less than 0.0220 W/(m·k).
Implementation Method 1
polyisocyanates are mixed with (b) compounds having groups which are reactive to isocyanates... to give a reaction mixture and the mixture is applied to a surface and cured to form insulation
Implementation Method 2
blowing agents... are reacted in such amounts that the isocyanate index is in the range 100-200... to form insulation
Data Source
AI summary
Described herein are processes for producing cold-flexible polyurethane insulation, in which (a) polyisocyanates are mixed with (b) compounds having groups which are reactive to isocyanates, (c) blowing agents, (d) catalysts, (e) plasticizers and optionally (f) further additives to give a reaction mixture and the mixture is applied to a surface and cured to form insulation. Also described herein is a polyurethane insulation obtainable by a process described herein.