Dual-Frequency Desalting Coalescer Current Feedback for Demulsifier Control

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Solution Overview

Problem

Conventional Gas-Oil Separation Plants (GOSP) lack effective monitoring and control mechanisms to optimize demulsifier dosage, leading to inefficient water separation and potential upsets due to the formation of rag layers in electrostatic coalescers, which are not proactively addressed by existing voltage-based feedback systems.

Innovation Solution

Implementing a demulsifier control algorithm that utilizes the rate of change of current measurements from Dual Frequency Desalting (DFD) technology to adjust demulsifier dosage dynamically, incorporating a current override PID controller to ensure stable operation and prevent upsets, with the capability to switch off high-pressure production trap (HPPT) monitoring when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If voltage-based feedback systems are used for monitoring electrostatic coalescers, then the system structure is simple, but the detection precision and ability to proactively address rag layer formation is insufficient

Engineering Contradiction:

Improvedetection precisionVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional voltage-based monitoring with a current measurement system that monitors current draw of individual transformer circuits. This substitution enables more precise detection of emulsion buildup conditions by measuring electrical current characteristics rather than voltage, providing earlier and more accurate warnings of rag layer formation while maintaining system simplicity through standard electrical measurements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If demulsifier dosage is increased to improve water separation efficiency, then separation efficiency improves, but chemical consumption increases

Engineering Contradiction:

Improveseparation efficiencyVSAvoidchemical consumption

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent implements a feedback control system where current measurements from the DFD device and HPPT apparatus continuously monitor emulsion conditions. The controller adjusts demulsifier dosage based on real-time current data, increasing dosage only when emulsion buildup is detected and decreasing it when conditions are stable. This feedback mechanism optimizes separation efficiency while minimizing unnecessary chemical consumption.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts demulsifier dosage rather than using fixed dosing rates. The controller modifies the dosage in real-time based on changing emulsion conditions detected through current measurements, allowing the system to adapt to varying crude oil properties and production conditions, thereby improving efficiency while reducing chemical waste.

Inventive Principle:

Principle #15Dynamics

3Productivity

If continuous monitoring of HPPT apparatus is maintained, then separation efficiency is optimized, but system complexity and operational burden increase

Engineering Contradiction:

Improveseparation efficiencyVSAvoidmonitoring system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent combines monitoring of both the DFD device and HPPT apparatus into a single integrated control system. The controller receives current measurements from both devices and coordinates demulsifier dosage adjustments based on combined feedback. This merging reduces operational complexity by consolidating monitoring functions while maintaining optimization of separation efficiency across the entire system.

Inventive Principle:

Principle #5Merging (Combining)

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

Enhances the efficiency of crude oil desalting processes by optimizing demulsifier dosage, reducing chemical consumption, and preventing upsets, thereby ensuring consistent and high-quality crude production.

Implementation Method 1

electrostatic coalescers for removing emulsified water and crude

Methodology Applied

Scientific EffectElectrostatic coalescence: Electrostatic Induction

Implementation Method 2

separate water from crude oil to produce dry crude

Methodology Applied

Scientific EffectPhase separation: Gravitation

Implementation Method 3

injecting demulsifier to separate free water

Methodology Applied

Scientific EffectSurface tension reduction: Surfactant

Data Source

PatentEP4182418B1Demulsifier control algorithm for dual frequency desalting electrostatic coalescers

Publication Date: 2025.10.08 SAUDI ARABIAN OIL CO

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AI summary

The present disclosure describes a computer-implemented method that includes: monitoring, at a gas oil separation plant (GOSP) facility that includes a high-pressure production trap (HPPT) apparatus and a Dual Frequency Desalting (DFD) device, a plurality of parameters, wherein the plurality of parameters include one or more current measurements from the DFD device, as well as gas temperature and demulsifier concentration from the HPPT; based on the one or more current measurements, determining a rate of change of the one or more current measurements from the DFD device; and in response to the rate of change as well as the gas temperature and the demulsifier concentration, adjusting a demulsifier dosage being injected at the HPPT apparatus.