Flexible Pipe Carcass Resistivity Layout for Zoned Heating
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Solution Overview
Problem
Unbonded flexible pipes used in subsea hydrocarbon transport lack the ability to dynamically adjust heating properties along their length, leading to inefficient heat distribution and potential temperature variations in critical sections.
Innovation Solution
The carcass of the unbonded flexible pipe is manufactured from electrically conductive elongate armour elements with varying electrical resistivity sections, achieved by altering the geometry, material, or winding degree of the elongate armour elements, allowing for different heat generation in specific sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If uniform electrical resistivity is used throughout the carcass, then the pipe structure is simple and easy to manufacture, but heat distribution is inefficient and cannot be optimized for critical sections
Solution Approach 1:
The carcass is divided into multiple sections with different electrical resistivity values tailored to specific requirements. Critical sections have higher resistivity for enhanced heating, while non-critical sections have lower resistivity. This local differentiation optimizes heat distribution where needed without uniformly increasing complexity throughout the entire pipe structure.
Solution Approach 2:
The continuous carcass structure is segmented into discrete sections, each with independently controlled electrical resistivity. This segmentation allows precise control over heat generation in different pipe regions, enabling optimized thermal management for specific operational requirements while maintaining overall structural integrity.
2Temperature
If heating capacity is increased throughout the entire pipe, then temperature control in critical sections improves, but material consumption and weight increase
Solution Approach 1:
Electrical resistivity is locally optimized in critical sections rather than uniformly increased throughout the pipe. This allows concentrated heating capacity where temperature control is most needed, while maintaining lower material usage and weight in non-critical sections where full heating capacity is not required.
Solution Approach 2:
Heating capacity is applied partially and selectively to only those sections requiring temperature control, rather than excessively increasing heating capacity throughout the entire pipe. This partial action approach achieves the necessary temperature control function with minimized material consumption and weight.
3Temperature
If uniform voltage and current are applied along the pipe length, then the electrical system is simple to operate, but heat generation cannot be optimized for different sections
Solution Approach 1:
The electrical system is configured to provide different voltage and current levels to different carcass sections based on their specific heating requirements. Critical sections receive higher electrical input for increased heat generation, while non-critical sections receive lower input. This localized electrical control optimizes heat generation without requiring complex overall system operation.
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
This design enables tailored heat distribution along the pipe length, optimizing heating capacity while reducing material consumption and weight, and allowing for efficient operation with varying voltage and current levels.
Implementation Method 1
The elongate armour element is electrically conductive and comprises a plurality of sections, wherein an electrical resistance in at least two of the sections is different from each other
Data Source
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AI summary
An unbonded flexible pipe (1) having a length and a longitudinal axis (9) and comprising, from inside and out, a carcass (2), an internal pressure sheath (3), at least one external armour layer (4,5,6,7) and an outer sheath (8). The carcass (2) comprises at least one elongate armour element helically wound to surround the center axis with a winding degree to the longitudinal axis. The elongate armour element is electrically conductive and comprises at least a first section and a second section along the length of the pipe (1) where the electrical resistance of the first section is different from the electrical resistance of the second section. In preferred embodiments this is achieved by the geometry and/or the material of the elongate armour element in the first section being different from the geometry and/or the material of the elongate armour element in the second section.