Flexible Pipe Heating Control for Stable Subsea Fluid Temperature
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Solution Overview
Problem
Unbonded flexible pipes used for transporting hydrocarbons in subsea applications face challenges in maintaining optimal fluid temperature, which can lead to component damage or blockages due to extreme temperatures, and existing heating systems lack efficient control mechanisms responsive to fluid temperature variations.
Innovation Solution
An electric heating system integrated into the unbonded flexible pipe, controlled by temperature sensors and a processing unit, adjusts electrical power input to maintain the fluid at a predetermined temperature between 30°C and 130°C, optimizing processing conditions and minimizing energy consumption by ensuring the pipe operates within a safe temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an electric heating system is integrated into the unbonded flexible pipe, then the fluid temperature can be maintained at optimal levels, but the device complexity increases
Solution Approach 1:
The heating system utilizes the electrically conductive armouring layers of the flexible pipe itself as the heating elements. By passing electric current through these existing structural layers, the pipe heats itself without requiring separate heating components, thereby maintaining temperature control while avoiding additional device complexity
Solution Approach 2:
The armouring layers serve dual functions: providing mechanical strength and structural support to the flexible pipe, while simultaneously acting as electrically conductive heating elements when electric current is applied. This multi-functionality eliminates the need for separate heating components
2Temperature
If continuous heating is applied to maintain fluid temperature, then the fluid arrives at the floating unit at optimal temperature, but energy consumption increases
Solution Approach 1:
Temperature sensors positioned along the flexible pipe continuously monitor the fluid temperature and provide feedback to a control system. Based on this feedback, the control system adjusts the electric power input to the heating system, applying heat only when and where needed to maintain optimal temperature, thereby minimizing energy consumption
Solution Approach 2:
Rather than applying continuous heating along the entire pipe length, the system applies heating locally and selectively based on measured temperature conditions. The electric power input is adjusted according to the specific thermal needs at different locations and times, optimizing energy efficiency
3Device complexity
If no temperature control is implemented, then the device complexity remains low, but the pipe and fluid are at risk of damage from extreme temperatures
Solution Approach 1:
The flexible pipe's existing electrically conductive armouring layers are utilized as heating elements, allowing the structure to protect itself from thermal damage by generating heat when electric current is applied, without requiring external heating devices or complex control systems
Solution Approach 2:
The heating system dynamically adjusts the electric power input based on real-time temperature measurements, increasing heating when temperatures drop and reducing or stopping heating when optimal temperature is reached, thereby preventing both overheating and underheating conditions that could damage the pipe or fluid
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 ensures the fluid arrives at the floating unit at an optimal temperature, reducing the need for further heating, minimizing process time, and preventing damage to the pipe, while also saving energy by precisely controlling the heating process.
Implementation Method 1
an electric heating system connected to an electric power source... the fluid in the first end of the pipe is heated to a temperature which corresponds to a predetermined temperature by means of the electric heating system
Data Source
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AI summary
The present invention relates to a method and a system for controlling the temperature of a fluid in an unbonded flexible pipe. The system comprises a floating unit (1) for processing, handling or storing a fluid and at least one unbonded flexible pipe (4) for transporting said fluid to the floating unit (1). The unbonded flexible pipe (4) comprises an electric heating system, and the temperature of the fluid in the unbonded flexible pipe (4) is measured and used to control the electrical input to the electric heating system in the unbonded flexible pipe (4). In an embodiment the electric input to the heating system is controlled so the fluid in the end of the flexible pipe (4) close to the floating unit (1) has a temperature substantially corresponding to a predetermined temperature.