Submersible Heat Exchanger for Pump Recirculation
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Solution Overview
Problem
In subsea hydrocarbon production, low flow rate conditions require artificial lift techniques, but pumps designed for maximum flow rates often operate inefficiently, and recirculation loops can cause temperature increases exceeding the design limits of manifolds, flow lines, and pumps, necessitating effective temperature control methods.
Innovation Solution
A submersible heat exchanger system that includes a coil with a housing and foundation, utilizing a sliding sleeve to adjust coolant flow and prevent temperature exceedance, allowing recirculation loops to maintain pump efficiency by cooling the fluid through a heat transfer medium like seawater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If recirculation loops are used to increase pump operational envelope and lower minimum flow rate, then pump efficiency is improved, but temperature increases exponentially surpassing maximum design temperature
Solution Approach 1:
A heat exchanger is introduced as an intermediary device between the recirculation loop and the pump inlet. This heat exchanger transfers heat from the recirculating hydrocarbon fluid to the surrounding seawater, preventing temperature buildup in the recirculation loop while maintaining pump operational efficiency. The heat exchanger acts as a mediator that allows the recirculation system to function without causing harmful temperature increases.
2Productivity
If pumps are designed for maximum flow rates, then productivity is improved, but pumps operate inefficiently under low flow rate conditions
Solution Approach 1:
The system incorporates a variable speed drive that dynamically adjusts the pump operating speed based on actual flow rate requirements. This allows the pump to maintain optimal efficiency across a wide range of flow rates by adapting its operating characteristics in real-time, rather than being fixed at maximum flow rate design conditions.
3Temperature
If pipe is arranged with bends to increase contact area with seawater for cooling, then heat transfer is improved, but device complexity increases
Solution Approach 1:
The heat exchanger utilizes natural convection currents in the seawater to provide cooling, eliminating the need for complex pumped cooling systems. The housing design allows seawater to flow naturally around the coil, using buoyancy-driven convection to maintain effective heat transfer without requiring additional pumping equipment or complex flow control mechanisms.
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 temperature, enabling pumps to operate over a wider range of flow rates, reducing capital costs and maintenance, and preventing damage from excessive heat.
Implementation Method 1
flowing at least a portion of the pressurized fluid through a first heat exchanger and back to the inlet of the pump
Implementation Method 2
utilizing a sliding sleeve to adjust coolant flow and prevent temperature exceedance, allowing recirculation loops to maintain pump efficiency by cooling the fluid through a heat transfer medium like seawater
Data Source
AI summary
Systems and methods for transporting a hydrocarbon are provided. The method can include introducing a fluid at a first pressure and a first temperature to an inlet of a pump and pressurizing the fluid within the pump to produce a pressurized fluid having a second pressure and a second temperature. The method can also include flowing at least a portion of the pressurized fluid through a first heat exchanger and back to the inlet of the pump. The heat exchanger can include a coil having an inlet and an outlet and a housing at least partially enclosing the coil and having a first opening and a second opening. A first end of the coil can be disposed proximate the first opening. The heat exchanger can also include a foundation for supporting the coil and the housing.