Subsea Heated Pipe Assembly With Sealing Tube Joule Heating
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Solution Overview
Problem
Existing heating solutions for single-walled subsea pipes are inefficient and unreliable due to the presence of external grids that are not watertight, leading to potential water influx and system breakdown.
Innovation Solution
A heated subsea pipe design featuring a transport tube electrically connected to a sealing tube made of conductive material, surrounded by an electrically insulating inner layer and a thermally insulating outer layer, with two parallel electrical circuits for efficient Joule heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external grid is used for current transport in single-walled pipes, then electrical heating can be applied, but the grid is not watertight leading to water influx and system breakdown
Solution Approach 1:
The patent introduces an intermediate sealing tube made of electrically conductive material between the transport tube and the heating circuit. This sealing tube acts as a mediator that provides both electrical conductivity for current flow and watertight sealing to prevent seawater infiltration, thereby resolving the contradiction between enabling electrical heating and preventing water ingress.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers with different properties: the transport tube for fluid flow, the electrically insulating inner layer for electrical isolation, the sealing tube for watertight sealing and current conduction, and the thermally insulating outer layer for heat conservation. This composite design allows each layer to address specific requirements simultaneously.
2Use of energy by moving object
If direct electrical heating is applied to the inner casing, then heating efficiency improves, but strong currents flow in seawater reducing efficiency
Solution Approach 1:
The electrically insulating inner layer serves as an intermediary that prevents direct electrical contact between the transport tube and seawater. This layer allows the transport tube to be heated by Joule effect while blocking the path for stray currents in seawater, thereby maintaining heating efficiency and reducing energy loss.
Solution Approach 2:
The patent applies different material properties to different regions: the transport tube is made electrically conductive for controlled heating, while the surrounding electrically insulating inner layer prevents uncontrolled current flow in seawater. This local differentiation of electrical properties optimizes heating efficiency while minimizing energy loss.
3Temperature
If thermal insulation is applied in double-walled pipes, then thermal performance improves, but the structure becomes more complex
Solution Approach 1:
The sealing tube performs multiple functions simultaneously: it provides watertight sealing, conducts electrical current for heating, and serves as a structural element. This multi-functionality reduces the need for separate components, thereby simplifying the overall structure while maintaining good thermal performance through the thermally insulating outer layer.
Solution Approach 2:
The patent merges the sealing function and electrical conduction function into a single sealing tube component, rather than using separate sealing elements and external grids. This consolidation reduces structural complexity while achieving both watertight protection and electrical heating capability.
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 provides high heating efficiency (85-90%) and reliability by preventing water influx and ensuring uniform heating along the pipe, suitable for deep water installations.
Implementation Method 1
two electrical cables (16a, 16b) connected, on the one hand, to an electric generator (14) and, on the other hand, to the transport tube (4) and to the sealing tube (8) of the pipe at a point situated between the two ends of the pipe so as to produce two parallel electrical circuits each traversed by an electric current for heating the transport tube of the pipe by Joule effect
Data Source
AI summary
A heated subsea pipe and process for transporting fluids, includes a plurality of pipe sections each having a transport tube for receiving the fluids, an electrically insulating inner layer arranged around the transport tube, a sealing tube made of electrically conductive material arranged around the electrically insulating inner layer, a thermally insulating outer layer arranged around the sealing tube. The transport tube is electrically connected to the sealing tube at each of the two ends of the pipe. The pipe includes two electrical cables connected to an electric generator and, to the transport tube and to the sealing tube of the pipe at a point situated between the two ends of the pipe to produce two parallel electrical circuits each traversed by an electric current for heating the transport tube of the pipe by Joule effect.