Inclined Subsea Heating Coil for Two-Phase Effluent Flow Stability
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Solution Overview
Problem
Existing subsea heating systems for metallic pipes used in hydrocarbon production face challenges such as high installation and maintenance costs, and the need for continuous heating along the entire pipe length, which is impractical for operational phases, and require large, heavy heating stations due to inefficiencies in heat transfer.
Innovation Solution
A subsea heating installation featuring inclined heated pipe sections connected by curved sections to form a heating coil, equipped with an induction heating system, promoting a distributed flow regime and enhancing heat exchange coefficients, thereby reducing the length and weight of the heating system while maintaining efficient thermal power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If electric heating cables are wound around subsea pipes for trace heating, then the two-phase effluent temperature is maintained above a critical threshold, but installation and maintenance costs significantly increase
Solution Approach 1:
The patent replaces the mechanical/electrical heating cable system with an induction heating system that uses electromagnetic fields to heat the pipe externally. The induction heating device generates an alternating magnetic field that induces eddy currents in the conductive pipe wall, producing heat without direct contact or embedded cables, thereby eliminating installation and maintenance costs associated with heating cables while maintaining effluent temperature control
Solution Approach 2:
The patent introduces an intermediary substance (conductive fluid or coating) between the induction heating device and the pipe, or uses the pipe wall itself as the intermediary to transfer electromagnetic energy to the effluent. This intermediary enables efficient heat transfer from the external induction source to the two-phase effluent without requiring internal heating elements
2Temperature
If electric heating cables are used for trace heating, then continuous heating along the entire pipe length is achieved, but the system becomes impractical for operational phases due to continuity requirements
Solution Approach 1:
The patent divides the heating system into discrete, modular induction heating units that can be independently installed at specific locations along the subsea pipe. Each unit is self-contained and can operate autonomously, so if one unit fails, others continue to function. This segmentation eliminates the requirement for continuous heating along the entire pipe length and improves system reliability during operational phases
Solution Approach 2:
The induction heating system operates in periodic or intermittent cycles rather than continuously, activating heating only when and where needed based on effluent temperature monitoring. This periodic operation reduces wear on heating components and allows the system to remain reliable during operational phases by avoiding continuous exposure to harsh subsea conditions
3Power
If local heating stations with horizontal pipe windings and solenoids are used, then heating is efficient, but very long pipe lengths must be heated which increases the weight and dimensions of the heating station
Solution Approach 1:
The patent transitions from heating long horizontal pipe sections to heating shorter vertical or inclined pipe sections using induction heating. By changing the spatial orientation and using the vertical dimension, the system achieves the same thermal power transfer in a more compact configuration, significantly reducing the weight and dimensions of the heating station while maintaining heating efficiency
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 significantly improves heat exchange coefficients, allowing for a drastic reduction in the length of heated pipe sections, reducing the size and weight of the heating system, and enabling efficient thermal power transfer for maintaining effluent temperature, thus preventing pipe blockages and operational disruptions.
Implementation Method 1
each heated pipe section being inclined with respect to the horizontal at an angle comprised between 2 and 10° in order to promote a distributed flow regime of the two-phase effluent and being provided with an induction heating system
Implementation Method 2
provided with an induction heating system
Implementation Method 3
promote a distributed flow regime of the two-phase effluent and being provided with an induction heating system
Data Source
AI summary
A subsea installation for heating a two-phase liquid/gas effluent circulating within a subsea casing, includes a plurality of heated pipe sections which are successively connected to one another by curved pipe sections to form a heating coil, each heated pipe section being inclined with respect to the horizontal at an angle comprised between 2 and 10° in order to promote a distributed flow regime of the two-phase effluent and being provided with an induction heating system.