Flexible Pipe PCM Layer for Subsea Fluid Temperature Hold
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Solution Overview
Problem
Existing flexible pipes used for transporting production fluids in deep and ultra-deep water environments face challenges in maintaining fluid temperature above 30°C to prevent solidification of waxes and hydrates, as conventional insulation methods are inadequate in retaining heat and require significant power for active heating or complex manufacturing processes.
Innovation Solution
Incorporating encapsulated or enclosed regions of thermally active materials with high latent heat of fusion in the flexible pipe body, which absorb and release heat based on environmental conditions, acting as both a heat storage reservoir and insulation layer to maintain fluid temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional insulation layers are used between the pressure sheath and outer sheath, then heat loss from the bore fluid is reduced, but the insulation is inadequate in retaining heat during shut-down periods in deep and ultra-deep water
Solution Approach 1:
The patent incorporates a phase change material (PCM) layer that utilizes phase transitions to maintain fluid temperature. The PCM absorbs latent heat during melting and releases it during solidification, providing thermal energy storage and release capabilities that conventional insulation cannot achieve. This ensures the bore fluid temperature remains above the solidification point of waxes and hydrates even during shut-down periods.
Solution Approach 2:
The patent creates a composite pipe structure combining conventional insulation layers with a phase change material layer. This composite construction integrates the heat resistance of traditional insulation with the thermal energy storage capability of PCM, achieving both reduced heat loss and reliable temperature maintenance during extended shut-down periods.
2Reliability
If active heating methods (electrical energy, hot water, steam) are used to maintain fluid temperature, then the desired temperature can be maintained indefinitely, but a significant amount of power is required and the system becomes more complicated
Solution Approach 1:
The phase change material layer serves itself by automatically absorbing and releasing thermal energy based on temperature conditions. During fluid flow, the PCM absorbs excess heat; during shut-down, it releases stored heat to maintain temperature. This self-regulating mechanism eliminates the need for external power sources or complex control systems required by active heating methods.
Solution Approach 2:
The patent utilizes the phase transition properties of the PCM to create a passive thermal management system. The material transitions between solid and liquid phases, absorbing latent heat during melting and releasing it during solidification, thereby maintaining fluid temperature without requiring external energy input or complex active heating infrastructure.
3Reliability
If thicker insulation layers are used to retain heat during shut-down periods, then temperature maintenance improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The phase change material provides enhanced thermal energy storage in a relatively thin layer compared to conventional insulation thickness required for the same effect. The latent heat capacity of the PCM allows it to store and release significant thermal energy, achieving reliable temperature maintenance during shut-down periods without requiring excessively thick insulation layers or complex multi-layer constructions.
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 solution effectively maintains fluid temperature above 30°C, preventing solidification of waxes and hydrates during shut-down periods and reducing the need for extensive insulation or high power consumption, while allowing for efficient heat retention and release as needed.
Implementation Method 1
the material acts to absorb heat or release 'stored' heat in accordance with the temperature of the local environment to which it is subjected
Implementation Method 2
a material having a high latent heat on phase change
Implementation Method 3
the material acts to absorb heat or release 'stored' heat in accordance with the temperature of the local environment
Implementation Method 4
a material having a high latent heat on phase change
Implementation Method 5
one or more layers of flexible pipe body, each layer being formed substantially of a thermally active material
Data Source
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AI summary
Apparatus and method for maintaining temperature in a sub-sea device, in particular in relation to fluid in the device. A material having a high latent heat on phase change is used to release latent heat to the fluid when the fluid temperature decreases towards a threshold value.