Polymer-Lined Steel Pipe for Controlled Liner Buckling
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Solution Overview
Problem
Subsea pipelines transporting hydrocarbons face issues with uncontrolled collapse of polymer protective linings during depressurization, leading to potential buckling and loss of corrosion protection, due to gas permeation and accumulation, which existing solutions complicate with adhesive coatings, gas discharge orifices, and perforations that weaken the pipeline or risk corrosion.
Innovation Solution
A steel pipeline design with an annular polymer lining featuring weakened angular portions for controlled buckling during depressurization, eliminating the need for external orifices and perforations, and maintaining the integrity of the pipeline by distributing buckling location and amplitude through interference fit and varying thickness or material properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an annular polymer protective lining is inserted in the steel pipeline, then corrosion protection is improved, but gas permeation causes uncontrolled collapse during depressurization
Solution Approach 1:
The protective lining is designed with non-uniform thickness, featuring weakened angular portions (thinner sections) and reinforced portions (thicker sections). This local variation in thickness creates predetermined collapse zones that control where buckling occurs during depressurization, preventing uncontrolled collapse while maintaining overall structural integrity and corrosion protection.
2Quantity of substance
If adhesive coating is applied to the inner surface of the steel tube, then gas accumulation is reduced, but manufacturing complexity increases significantly
Solution Approach 1:
The invention removes the adhesive coating layer from the manufacturing process entirely. Instead of applying adhesive to bond the protective lining to the steel tube, the system relies on the mechanical interference fit and the controlled collapse mechanism to manage gas accumulation, significantly simplifying the manufacturing process while maintaining effectiveness.
Solution Approach 2:
The protective lining is designed to self-regulate gas accumulation through its weakened angular portions. During depressurization, the lining automatically collapses in controlled zones to accommodate gas volume changes without requiring external adhesive bonding or active gas management systems, enabling the structure to self-adjust to pressure variations.
3Object-generated harmful factors
If outer orifices and gas discharge lines are added, then gas venting is improved, but pipeline integrity is weakened and leakage risk increases
Solution Approach 1:
The invention eliminates outer orifices, gas discharge lines, and associated drilling operations from the pipeline design. By incorporating gas accommodation directly into the protective lining structure through weakened angular portions, the system removes the need for external gas venting pathways, thereby maintaining pipeline integrity and eliminating leakage risks associated with additional penetration points.
4Object-generated harmful factors
If perforations are made in the protective lining, then gas discharge is enabled, but corrosion risk to the steel tube increases
Solution Approach 1:
The invention removes the need for perforations in the protective lining. Instead of creating holes that expose the steel tube to corrosive fluids and gases, the system uses the weakened angular portions to control collapse and accommodate gas volume changes, eliminating direct exposure pathways and associated corrosion risks.
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 effectively controls the collapse of the protective lining during depressurization, preserving pipeline integrity and preventing leakage, while allowing the lining to return to its original shape upon repressurization, without compromising corrosion protection or requiring complex maintenance.
Implementation Method 1
an annular protective lining made of polymer material, inserted in an interference fit inside the tube against an inner surface
Implementation Method 2
the transported fluids are corrosive to the steel making up the tubes... gas tends to penetrate through the protective lining to be housed in the interstitial space
Data Source
AI summary
A pipe for transporting fluids with control of the buckling of the internal anti-corrosion liner includes a steel tube intended to receive a flow of fluids to be transported, and an annular protective lining made of polymer material, inserted in an interference fit inside the tube against an inner surface thereof and intended to ensure protection of the steel against corrosion of the fluids to be transported, the protective lining having, in a cross-section plane, at least a weakened angular portion whose mechanical resistance to radial deformation is lower than that of the remaining angular portion of the protective lining so as to control the angular location and to promote the axial propagation of buckling of the protective lining following a depressurization of the pipeline.