Subsea Preconditioning Unit for Pressure Booster Density Control
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Solution Overview
Problem
Existing subsea pressure elevation systems face challenges in controlling fluid temperature and pressure, leading to potential damage to equipment due to unknown fluid characteristics and the risk of hydrate formation, especially when dealing with dense gases like natural gas rich in CO2.
Innovation Solution
A subsea system with a passive cooler and secondary line for temperature control, using sensors to measure temperature and pressure, and a bypass line with a control valve to adjust fluid flow, ensuring the fluid meets the operational parameters of the pressure boosting device, thereby preventing equipment damage and hydrate formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passive cooler is used for cooling the process fluid, then the temperature control is simple and reliable, but the outlet temperature cannot be precisely controlled and thermal load varies
Solution Approach 1:
A temperature control unit is introduced as an intermediary component between the passive cooler and the process fluid line. This unit actively monitors and adjusts the temperature of the process fluid, compensating for the passive cooler's inability to precisely control outlet temperature. The temperature control unit acts as a mediator that maintains reliable cooling while achieving precise temperature control.
2Temperature
If active heat exchangers with convection control are used, then temperature control precision is improved, but the system complexity and number of failure points increase
Solution Approach 1:
The heat exchanger system is segmented into distinct functional components: a passive cooler for primary cooling and a separate temperature control unit for precise temperature regulation. This segmentation allows each component to perform its specific function optimally while reducing the overall system complexity compared to a fully active heat exchanger system.
3Ease of operation
If the process fluid temperature is not controlled, then the system operation is simple, but equipment downstream may be damaged due to unknown fluid characteristics
Solution Approach 1:
Temperature control is implemented as a preliminary action before the process fluid enters downstream equipment. The temperature control unit ensures that the fluid characteristics are known and controlled in advance, preventing potential damage to downstream equipment while maintaining simple operation through automated control.
4Adaptability or versatility
If the pressure boosting device operates with fluid outside its operational window, then the system is more adaptable to varying well conditions, but the equipment may be damaged
Solution Approach 1:
A feedback control system is implemented that continuously monitors the process fluid characteristics and adjusts the cooling and temperature control mechanisms accordingly. This feedback loop ensures the fluid parameters remain within the pressure boosting device's operational window, maintaining both adaptability to varying well conditions and equipment safety.
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 system effectively controls the outlet temperature of the process fluid, maintaining it within the operational window of the pressure boosting device, preventing equipment damage and ensuring stable operation by adjusting fluid density and temperature.
Implementation Method 1
In a passive subsea heat exchanger, the process fluid passes through tubes in which the heat exchange occurs with the seawater, simply using the principle of thermal conduction.
Implementation Method 2
the bypass line comprises a control valve for varying the amount of process fluid flowing therethrough and a temperature control unit for measuring a temperature in the process fluid in the bypass line
Implementation Method 3
One consequence of the increase in fluid pressure is the increase in temperature. This increase in temperature in the fluid is proportional to the increase in pressure.
Data Source
AI summary
A subsea system (1) connected to a subsea well (4) for boosting a process fluid flowing out of the well, comprising: —a preconditioning arrangement (2) connectable to a process fluid line from a well, wherein the preconditioning arrangement comprises at least one sensor for measuring temperature and one sensor for measuring pressure of the process fluid—means for estimating density of the process fluid based on measured temperature and pressure, —a cooler system (20, 21) comprising at least a first cooler for cooling the process fluid wherein the subsea system further comprises: —a pressure boosting device (3) arranged downstream of the preconditioning arrangement (2), the pressure boosting device having an operational window dictating operational parameter in terms of maximum and minimum allowable density of the process fluid entering the pressure boosting device (3).