PE-RT Sealing Sheaths for Blister-Resistant Flexible Underwater Pipes
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Solution Overview
Problem
Flexible underwater pipes used for transporting hydrocarbons face the blistering phenomenon due to gas absorption in polyethylene sealing sheaths, leading to irreversible damage and loss of sealing function, especially at high pressures and temperatures, limiting their lifespan and operational range.
Innovation Solution
Incorporating a polyethylene with enhanced heat resistance (PE-RT) as a sealing sheath, which is less susceptible to blistering at higher temperatures and pressures, and is more cost-effective than alternative materials like PVDF, while maintaining mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional polyethylene is used as sealing sheath, then cost is reduced and ease of manufacture is improved, but resistance to blistering at high temperature and pressure deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the polyethylene by introducing specific comonomers (at least one alpha-olefin with 6-10 carbon atoms) during polymerization. This modifies the molecular structure to create polyethylene with enhanced heat resistance that maintains resistance to blistering at high temperatures and pressures while remaining manufacturable through conventional processes.
Solution Approach 2:
The patent creates a composite polyethylene material by copolymerizing ethylene with specific alpha-olefins (such as hexene or octene). This composite structure combines the benefits of polyethylene's processability with the enhanced thermal and pressure resistance provided by the comonomer units, achieving both reliability and ease of manufacture.
2Duration of action of stationary object
If polyethylene is used as sealing sheath, then ease of operation and cost are improved, but lifespan under high pressure and temperature deteriorates due to gas absorption and blistering
Solution Approach 1:
The patent modifies the polymerization parameters by controlling the type and amount of alpha-olefin comonomer (6-10 carbon atoms) incorporated into the polyethylene chain. This parameter change enhances the material's resistance to gas absorption and blistering, extending the pipe's lifespan under high pressure and temperature while maintaining ease of operation through conventional installation and handling procedures.
3Reliability
If polyethylene sealing sheath is used, then manufacturing simplicity is improved, but operational reliability at high temperature deteriorates due to blistering phenomenon
Solution Approach 1:
The patent changes the chemical composition parameters of the polyethylene by incorporating specific alpha-olefin comonomers (6-10 carbon atoms) during polymerization. This creates a material with inherently enhanced heat resistance that maintains operational reliability at high temperatures without requiring additional protective layers or complex structural modifications, thus avoiding increased device 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 use of PE-RT in flexible underwater pipes significantly enhances resistance to blistering, allowing operation at higher pressures and temperatures without losing sealing functionality, extending the pipe's lifespan and reducing costs compared to traditional polyethylene or PVDF-based solutions.
Implementation Method 1
the polymeric material of the sealing sheath absorbs the gases contained in the petroleum fluid depending on their chemical nature (via their solubility coefficient) and on the partial pressure of each of them
Implementation Method 2
The saturation time of the polymer, equilibration of the system, as for it depends on the diffusion coefficients
Data Source
AI summary
A flexible underwater pipe for transporting hydrocarbons, including a plurality of layers, at least one of which includes a polyethylene having enhanced heat resistance, to its preparation method and to its use for transporting hydrocarbons.