Gravity Separator Optimization via CFD Droplet Modeling

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Solution Overview

Problem

Existing systems for designing and controlling gravity separators for oil-water emulsions are inefficient due to oversizing or undersizing issues, as they do not account for true geometry, multidimensional flow fields, droplet size distribution, and emulsion stability, leading to suboptimal separation efficiency.

Innovation Solution

A computer-implemented method using computational fluid dynamics (CFD) to model and optimize gravity separator systems, incorporating Eulerian multiphase modeling and population balance modeling to simulate droplet size evolution and phase interaction, allowing for precise adjustment of operational parameters to maximize separation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If retention time design criteria are used for separator sizing, then design simplicity is maintained, but separation efficiency deteriorates due to oversizing or undersizing

Engineering Contradiction:

Improvedesign simplicityVSAvoidseparation efficiency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent transforms the separator design approach from using simple retention time parameters to using CFD-simulated parameters including multidimensional flow fields, droplet size distribution, and emulsion stability metrics. This parameter transformation enables accurate prediction of separation efficiency while optimizing separator size, resolving the contradiction between design simplicity and separation efficiency.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If single droplet transport models are used, then computational complexity is reduced, but prediction accuracy deteriorates due to ignoring multidimensional flow fields

Engineering Contradiction:

Improvecomputational complexityVSAvoidprediction accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent creates a virtual CFD model that copies and simulates the actual separator geometry and flow conditions. This virtual copy allows comprehensive multidimensional flow field analysis and droplet size distribution modeling without requiring physical experiments, achieving high prediction accuracy while keeping the actual separator design simple.

Inventive Principle:

Principle #26Copying

3Ease of manufacture

If average retention time is used for design, then design process is simplified, but separation performance deteriorates due to ignoring droplet size distribution

Engineering Contradiction:

Improvedesign process simplicityVSAvoidseparation performance

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent changes the design parameters from average retention time to a comprehensive set including droplet size distribution, flow field characteristics, and emulsion stability. The CFD model calculates these parameters to predict separation performance accurately, enabling optimized separator design that achieves high productivity without excessive complexity.

Inventive Principle:

Principle #35Parameter changes

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 enables more accurate prediction and optimization of separation efficiency, reducing carryover of immiscible phases and improving the design and operation of gravity separators, leading to better process control and capital expenditure efficacy.

Implementation Method 1

The gravity separators operate on the principle of providing adequate settling time to the immiscible phases in a relatively quiet horizontal or vertical flow. Oil droplets rise to the oil-water interface and water droplets settle to the interface.

Methodology Applied

Scientific EffectGravity separation: Gravitation

Implementation Method 2

Crude oil in oil fields often times forms an emulsion with water... water-in-oil (w/o) emulsions [water is the dispersed phase, oil is the continuous phase] and oil-in-water (o/w) emulsions

Methodology Applied

Scientific EffectDensity difference: Density Gradient

Data Source

PatentUS10870070B2Processes for analysis and optimization of multiphase separators, particularly in regard to simulated gravity separation of immiscible liquid dispersions

Publication Date: 2020.12.22 SAUDI ARABIAN OIL CO

AI summary

The present invention is directed to systems and methods for evaluating performance, performing process control, optimization and design of gravity separation process systems that are used to separate immiscible liquid dispersions (e.g., water-in-oil, oil-in-water mixtures) and emulsions for two-phase (liquid-liquid) or three-phase (gas-liquid-liquid) systems. According to one aspect, the design, simulation and control of such systems is performed using computational fluid dynamics (CFD) software that is configured for determining the separation efficiency of separators on the basis of the true geometry and multidimensional flow field and for a distribution of droplet sizes with the influence of the emulsion concentration on the rheology of the oil-in-water or water-in-oil dispersion. The results of the CFD simulations can be used to adjust input parameters of the separator to maximize the separation efficiency of the separator such that it outputs liquid streams containing minimal amounts of immiscible liquid dispersions.