Subsea Heated Pipe Circuit Layout for Leak-Resistant Joule Heating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing single-walled subsea pipes face issues with fluid cooling and blockage due to hydrate formation and solid deposits, and existing active heating solutions suffer from inefficiency and reliability due to water ingress and current leakage.
Innovation Solution
A single-walled subsea pipe design with an electrically conductive sealing tube surrounded by an insulating layer and a thermally insulating outer layer, connected by electrical cables to form parallel circuits for Joule heating, ensuring watertightness and high efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If direct electrical heating is applied to the inner steel casing of a single-walled pipe, then heating efficiency is improved, but water ingress and current leakage reduce reliability
Solution Approach 1:
The pipe is divided into two separate steel casings (inner and outer) with distinct functions. The inner casing serves as the fluid transport conduit while the outer casing acts as the electrical heating element and protective barrier. This segmentation allows each component to be optimized for its specific function, preventing water ingress issues while maintaining heating efficiency.
Solution Approach 2:
An intermediate insulation layer is introduced between the inner and outer casings. This intermediary layer serves multiple purposes: it provides thermal insulation to maintain heating efficiency, acts as an electrical insulator to prevent current leakage, and provides mechanical protection. This mediator resolves the contradiction by enabling direct electrical heating without the harmful effects of water ingress and current leakage.
2Temperature
If thermal insulation is placed between inner and outer casings in double-walled pipes, then thermal performance is improved, but mechanical protection is reduced
Solution Approach 1:
Different regions of the pipe structure are assigned different properties. The inner casing provides mechanical strength and fluid containment, while the outer casing provides electrical conductivity for heating and additional mechanical protection. The intermediate layer provides thermal insulation. This local differentiation of qualities allows each layer to excel at its specific function without compromising overall structural integrity.
Solution Approach 2:
The pipe structure employs a composite design with multiple materials: steel for the casings (providing mechanical strength and electrical conductivity), and insulation material for the intermediate layer (providing thermal insulation). This composite structure combines the advantages of different materials to simultaneously achieve mechanical protection and thermal performance.
3Power
If an external grid is used for current transport in single-walled pipes, then heating capability is improved, but watertightness is compromised
Solution Approach 1:
The functions of structural support, fluid containment, and electrical heating are merged into the outer steel casing. This single component simultaneously provides mechanical strength, maintains watertightness, and serves as the electrical conductor for heating. This eliminates the need for separate external grids that would compromise watertightness.
Solution Approach 2:
The outer steel casing is designed to perform multiple functions: it serves as the structural outer shell, provides watertight protection against seawater ingress, and acts as the electrical conductor for direct electrical heating. This multi-functional design resolves the contradiction by integrating heating capability without compromising watertightness.
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 design provides efficient and reliable heating with 85-90% current participation in fluid heating, preventing water ingress and enhancing Joule heating uniformity and efficiency.
Implementation Method 1
produce two parallel electrical circuits each traversed by an electric current for heating the transport tube of the pipe by Joule effect
Implementation Method 2
a thermally insulating outer layer arranged around and covering the sealing tube
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.