Subsea Thermal Insulation via Nested Heat Storing Medium
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Solution Overview
Problem
Subsea oil and gas production installations face issues with hydrate formation due to cooling of production fluid by ambient cold sea water, leading to pipe clogging, which existing thermal insulation methods like heat banks do not adequately address, especially during production interruptions.
Innovation Solution
A device with an external casing enclosing a fluid chamber containing a heat-storing fluid and additional heat storing members, which allows for two-stage heat transfer to delay cooling of protected elements by transferring heat between the fluid and the heat storing members, preventing direct heat transfer to the casing and enhancing thermal insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heat bank with fluid chamber is used to thermally insulate subsea elements, then thermal insulation performance is improved, but device complexity increases due to the need for additional heat storing members and two-stage heat transfer mechanisms
Solution Approach 1:
The heat storing member is nested within the fluid chamber, with the heat storing member containing a medium that is itself nested within a chamber filled with heat-storing fluid. This nested structure allows the system to achieve enhanced thermal insulation through multiple stages of heat transfer while maintaining a compact configuration that manages complexity.
Solution Approach 2:
The patent introduces an intermediary heat storing member with a specific medium that acts as a mediator between the external environment and the protected element. This intermediary component enables two-stage heat transfer, where the medium in the heat storing member first exchanges heat with the surrounding fluid, then transfers heat to the protected element, thereby enhancing thermal insulation performance.
2Power
If heat transfer directly from heat storing member to casing is allowed, then heat transfer efficiency is improved, but thermal insulation effectiveness deteriorates due to direct heat loss to ambient sea water
Solution Approach 1:
The patent employs the heat-storing fluid as an intermediary medium that separates the heat storing member from the external casing. This intermediary fluid layer prevents direct heat transfer from the heat storing member to the casing, thereby maintaining thermal insulation effectiveness while still allowing controlled heat transfer through the fluid medium.
Solution Approach 2:
The patent extracts the heat transfer function from direct contact between the heat storing member and the casing. By removing the direct heat transfer path and replacing it with indirect heat transfer through the fluid medium, the system prevents harmful heat loss to the ambient sea water while maintaining necessary thermal management capabilities.
3Adaptability or versatility
If production fluid heat input is reduced or interrupted, then operational flexibility is improved, but cooling of protected element accelerates due to loss of heat source
Solution Approach 1:
The system performs preliminary action by pre-heating the heat-storing fluid and the medium in the heat storing member during normal operation. This stored thermal energy acts as a reserve that can be deployed when the production fluid heat input is reduced or interrupted, thereby delaying the cooling of the protected element and providing operational flexibility.
Solution Approach 2:
The heat storing member and fluid chamber system provides self-service thermal management capability. When external heat input from the production fluid is reduced or interrupted, the system uses its own stored thermal energy to maintain the temperature of the protected element, thereby ensuring continuous thermal protection without requiring continuous external heat input.
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 device effectively delays cooling of subsea elements by utilizing the heat stored in the fluid and heat storing members, maintaining thermal insulation even when heat input from the production fluid is reduced or interrupted, thereby preventing rapid cooling from ambient sea water.
Implementation Method 1
transfer of heat from the fluid surrounding the heat storing member to the medium in the heat storing member when the temperature of the medium in the heat storing member is lower than the temperature of the fluid surrounding the heat storing member
Implementation Method 2
the heat storing member containing a medium having heat-storing capacity so as to allow transfer of heat from the fluid surrounding the heat storing member to the medium in the heat storing member
Implementation Method 3
As the fluid in the internal fluid chamber loses heat to the ambient sea water by heat transfer through the external casing
Implementation Method 4
The heat storing member is separated from the external casing by the fluid occupying the space in the internal fluid chamber between the heat storing member and the external casing, and heat transfer directly from the heat storing member to the external casing is thereby prevented
Data Source
AI summary
A device for thermally insulating at least one element of a subsea installation from ambient cold sea water, the device comprising an external casing which encloses an internal fluid chamber. The fluid chamber accommodates a fluid having heat-storing capacity, the element being received in the fluid chamber with the fluid surrounding the element so as to allow the fluid to delay cooling of the element by means of heat stored in the fluid. A heat storing member is mounted in the fluid chamber so as to be surrounded by the fluid. The heat storing member contains a medium having heat-storing capacity so as to allow transfer of heat from the fluid to the medium in the heat storing and vice versa to thereby allow the heat storing member to delay cooling of the fluid by means of heat stored in the medium in the heat storing member.