Phase Angle Control in Electrostatic Oil-Water Separation
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Solution Overview
Problem
Existing electrostatic separators for oil and gas extraction face challenges in controlling the separation of oil and water due to variable and unpredictable properties of the hydrocarbon stream, leading to potential breakthroughs of water in oil or oil in water, necessitating improved methods for efficient phase separation.
Innovation Solution
The method involves using a separation apparatus with an electric field applied by multiple electrodes, where a time-varying voltage is applied to create an electric field within the liquid mixture, and phase angle sensors monitor and control the separation process by adjusting the voltage characteristics to minimize phase angle, ensuring optimal separation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous operation with fixed voltage is used, then the separator operates continuously, but water breakthroughs or oil breakthroughs occur due to variable feed properties
Solution Approach 1:
The patent applies dynamics by transitioning from fixed voltage to variable voltage operation. The controller dynamically adjusts the voltage applied to electrodes based on real-time monitoring of separation performance parameters, allowing the system to adapt to variable feed properties while maintaining continuous operation and preventing breakthroughs
Solution Approach 2:
The patent implements feedback control by monitoring separation performance (such as water content in oil phase or oil content in water phase) and using this information to adjust the voltage applied to electrodes. This closed-loop control ensures reliable separation performance during continuous operation by automatically responding to changes in feed composition
2Productivity
If voltage is increased to improve separation speed, then separation efficiency improves, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts voltage levels based on actual separation needs rather than operating at constant high voltage. By monitoring separation performance and feed properties, the controller applies only the necessary voltage to achieve target separation speed, avoiding excessive energy consumption while maintaining productivity
Solution Approach 2:
The patent changes the voltage parameter dynamically based on process conditions. Rather than maintaining fixed high voltage for maximum separation speed, the system adjusts voltage levels to match actual separation requirements, optimizing the balance between separation speed and energy consumption
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 approach enhances the efficiency and control of oil-water separation by adjusting the voltage characteristics based on phase angle measurements, thereby minimizing phase angle and achieving better separation performance, reducing the risk of breakthroughs and improving the separation process.
Implementation Method 1
Electric fields are typically employed to speed separation of oil and water. The water typically has some amount of salt that increases its conductivity and its reaction to the effect of an electric field relative to oil.
Implementation Method 2
EP3563934 A1 describes a method of controlling an AC power supply system supplying an AC output voltage to electrodes of an electrostatic coalescer. The method comprises the steps of measuring parameters representative of an output current and the output voltage of the power supply system, identifying a phase difference between the output current and the output voltage
Data Source
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AI summary
Embodiments described herein provide a method of separating a liquid mixture, comprising providing a liquid mixture to a separator, electrically coupling a power circuit to the liquid mixture inside the separator, applying a time-varying voltage to the power circuit, detecting a phase angle in the power circuit; and controlling the phase angle by adjusting a characteristic of the time-varying voltage.