Polyurethane Elastomer Coating for Subsea Pipeline Insulation
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Solution Overview
Problem
Existing polyurethane elastomers used in subsea applications lack adequate hydrolytic and thermal stability, leading to degradation when exposed to seawater and varying temperatures and pressures, resulting in inefficient insulation and increased production costs due to inadequate coating processes.
Innovation Solution
A flexible polyurethane elastomeric composition is developed, comprising an isocyanate component and an isocyanate-reactive component with a polydiene polyol, which provides hydrolytic and thermal stability, flexibility, and effective insulation for subsea structures by reacting the components to form a stable coating that maintains the integrity of petroleum fuels during transportation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing polyurethane elastomers are used as exterior coatings on subsea pipelines, then the pipelines can be insulated to maintain fuel temperature, but the elastomers degrade when exposed to seawater and varying temperatures and pressures, leading to inadequate insulation and increased production costs
Solution Approach 1:
The patent changes the chemical parameters of the polyol component by specifying a polydiene polyol with average hydroxyl functionality of no greater than about 3 and number average molecular weight of from 1000 to 3000 g/mol. This parameter change in the polymer structure provides enhanced hydrolytic and thermal stability, allowing the elastomer coating to maintain its insulating properties and structural integrity under subsea conditions of varying temperature and pressure for extended service life
Solution Approach 2:
The patent creates a composite elastomeric composition by combining an isocyanate component with a polydiene polyol component in specific proportions (isocyanate component at 30-60 wt.-% of total composition). This composite material approach leverages the complementary properties of both components, where the polydiene polyol provides hydrolytic stability and the isocyanate provides crosslinking and mechanical strength, resulting in a coating that resists degradation from seawater exposure and thermal cycling
2Productivity
If the fuel temperature is allowed to drop due to cold seawater, then the fuel becomes too viscous to flow efficiently through pipelines, but adding insulation increases the complexity and cost of the pipeline system
Solution Approach 1:
The elastomer coating serves multiple functions simultaneously: it provides thermal insulation to maintain fuel temperature and prevent excessive viscosity, offers mechanical protection against seawater exposure and pressure, and ensures flexibility for pipeline manipulation during installation and operation. This multi-functionality eliminates the need for separate insulation layers or protective coatings, simplifying the overall pipeline system while maintaining fuel flow efficiency
Solution Approach 2:
The patent employs a flexible elastomer coating that forms a continuous protective film on the pipeline exterior. This thin flexible film provides adequate thermal insulation to prevent fuel temperature drop while allowing the pipeline to be manipulated, bent, and installed in complex subsea configurations. The flexibility of the coating eliminates the need for rigid insulation structures, reducing system complexity and installation cost
3Ease of manufacture
If existing elastomer coating processes are used, then the coating can be applied to pipelines, but the processes are noneconomical and contribute to increased production costs
Solution Approach 1:
The patent optimizes the compositional parameters of the elastomer formulation, specifically setting the isocyanate component at 30-60 wt.-% of the total composition and using a polydiene polyol with controlled molecular weight (1000-3000 g/mol). These parameter changes improve the coating's performance and durability, reducing maintenance and replacement costs over the pipeline's lifetime, thereby improving the overall economics of the coating process despite potentially higher initial material costs
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 polyurethane elastomeric composition exhibits superior hydrolytic and thermal stability, preventing degradation and ensuring efficient fuel flow through subsea structures, while also allowing for flexible manipulation of coated structures, thus addressing the limitations of existing elastomers and reducing production costs.
Implementation Method 1
the polyurethane elastomeric composition includes the reaction product of an isocyanate component and an isocyanate-reactive component
Implementation Method 2
Insulation is required to maintain a relatively high temperature of the petroleum fuels such that the fuels, such as oil and gas, can easily flow through the subsea pipelines and other subsea structures
Implementation Method 3
Existing polyurethane elastomers do not exhibit adequate hydrolytic stability and tend to decompose or breakdown when exposed to water, including seawater
Data Source
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AI summary
A polyurethane elastomeric composition includes the reaction product of an isocyanate component and an isocyanate-reactive component. The isocyanate- reactive component includes a polydiene polyol present in the isocyanate-reactive component in an amount of greater than 0 and less than about 95 parts by weight based on 100 parts by weight of the isocyanate-reactive component. The polydiene polyol has an average hydroxy functionality of no greater than about 3 and a number average molecular weight of from about 1000 to less than about 2000 g/mol.