Subsea Dosing Pump Stepper Motor Plunger
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Solution Overview
Problem
In subsea production lines, phase separation of mixed phases such as oil, water, and gas is challenging, especially when they form emulsions, requiring small amounts of de-emulsifiers to be injected continuously at high pressures, which is difficult to achieve efficiently with existing technologies.
Innovation Solution
A subsea deployable pumping system that injects de-emulsifiers or other chemicals at controlled rates of less than 10 milliliters per minute using a stepper motor-driven plunger mechanism within a pressure-compensated housing, capable of withstanding high pressures and deep-sea environments, to aid in phase separation and fluid sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If de-emulsifiers are injected at high pressure into subsea flow lines, then phase separation is achieved, but the injection rate becomes difficult to control and exceeds 10 milliliters per minute
Solution Approach 1:
The patent replaces conventional high-pressure mechanical injection systems with a precision dosing pump system that uses a stepper motor to control plunger displacement. This substitution enables precise control of injection rate (less than 10 milliliters per minute) while maintaining the ability to inject at high pressures up to 10,000 psi, resolving the contradiction between achieving phase separation and controlling injection rate.
Solution Approach 2:
The patent changes the control parameter from uncontrolled high-pressure flow to precisely controlled dosing rate. By using a stepper motor-driven plunger mechanism, the system can adjust the injection rate parameter independently while maintaining high pressure capability, allowing de-emulsifier injection at controlled rates of less than 10 milliliters per minute while still achieving effective phase separation.
2Stress or pressure
If a pump is deployed in deep-sea environment, then high pressure injection is possible, but the pump must withstand extreme pressure conditions
Solution Approach 1:
The patent employs a pressure-compensated housing design that uses flexible membrane separations to isolate the pump mechanism from external deep-sea pressure. The housing maintains internal pressure compensation through flexible membranes that allow pressure equalization while protecting internal components, enabling the pump to operate reliably at injection pressures up to 10,000 psi while withstanding deep-sea environmental pressures.
Solution Approach 2:
The patent introduces a pressure-compensating medium (fluid) as an intermediary between the external deep-sea environment and the internal pump mechanism. This intermediary fluid transmits external pressure changes to the pump housing, allowing the pump to maintain stable internal pressure conditions while withstanding extreme external pressures, thus ensuring reliability in deep-sea deployment.
3Quantity of substance
If de-emulsifier is added continuously at small amounts, then phase separation is maintained, but the injection system becomes complex
Solution Approach 1:
The patent implements a self-regulating dosing system where the stepper motor controller automatically adjusts plunger displacement based on predetermined programming. The system performs self-service by automatically controlling the injection of de-emulsifier at precise rates without requiring complex external control systems or manual intervention, thereby maintaining simple operation despite the precision required for small dosages.
Solution Approach 2:
The patent divides the injection function into discrete, controllable segments through the use of a stepper motor that moves the plunger in precise incremental steps. This segmentation allows the system to inject de-emulsifier at controlled small amounts (less than 10 milliliters per minute) by accumulating these discrete increments over time, simplifying the control mechanism while achieving precise dosage control.
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
Enables effective and controlled injection of de-emulsifiers into high-pressure subsea flow lines, facilitating phase separation and allowing for accurate sampling of desired phases, while maintaining robustness and reliability in deep-sea conditions.
Implementation Method 1
a plunger disposed within the housing configured to fit tightly within the cylindrical cavity such that injection fluid within the cylindrical cavity is forced through the injection port when the plunger is driven in a longitudinal direction
Implementation Method 2
the housing is filled with a liquid, such as oil, and the system also includes a pressure compensator configured to match pressure of the liquid with seawater pressure outside the housing
Implementation Method 3
a stepper motor configured to controllably rotate a drive shaft
Data Source
AI summary
A system is described for injecting small controlled amounts of fluid, such as de-emulsifier, into a flowing line at high pressure, in a high-pressure environment such as a subsea environment. The system is connected to the flowing line by tubing lines. It is enclosed either in a high-pressure vessel able to withstand high external pressure or in a vessel that is pressure-matched with the environment. The system is able to inject a controlled volume of fluid into the flowing line at relatively low injection rates.