Electrostatic Coalescing Oil/Water Separator
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Solution Overview
Problem
Current methods for separating water from crude oil-water mixtures are inefficient, as they rely on gravitational separation which is not effective for smaller water droplets, leading to high energy consumption and operational challenges.
Innovation Solution
An electrostatic coalescence method is employed, where an electrostatic field is applied to a water-and-oil mixture within an elongated inlet vessel, causing water droplets to coalesce and separate from the oil, with the coalesced water flowing downward and oil upward, facilitated by a series of vessels and electrodes to enhance separation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gravitational separation is used to separate water from oil, then the separation process is simple, but it is not effective for smaller water droplets leading to low separation efficiency
Solution Approach 1:
The patent replaces the purely mechanical gravitational separation system with an electrostatic field-based coalescence system. High-voltage electrodes generate an electrostatic field that induces dipole moments in water droplets, causing them to attract and coalesce into larger droplets that can then be efficiently separated by gravity. This substitution of mechanical gravity-only separation with electrostatic assistance resolves the contradiction by enabling effective separation of small droplets without requiring excessively complex mechanical structures.
Solution Approach 2:
The patent changes the physical state and properties of water droplets by applying an electrostatic field. The high voltage (typically 10-100 kV) induces polarization in the water droplets, transforming them from non-coalescing small droplets into polarized droplets that actively seek each other and merge. This parameter change in droplet behavior (from stable dispersion to active coalescence) enables efficient separation of previously inseparable small droplet sizes.
2Manufacturing precision
If traditional separation methods are used, then energy consumption is low, but separation efficiency for small water droplets is insufficient
Solution Approach 1:
The patent substitutes energy-intensive mechanical separation methods (such as centrifugal separation or filtration) with a more energy-efficient electrostatic coalescence process. The electrostatic field requires relatively low power input compared to mechanical systems, while achieving superior separation efficiency for small water droplets. The energy is applied only during the coalescence phase, after which gravity performs the separation work, minimizing continuous energy consumption.
Solution Approach 2:
The patent employs periodic or pulsed high-voltage application to the electrodes rather than continuous high-power input. The electrostatic field is applied in cycles or pulses sufficient to induce coalescence, then reduced or removed, allowing gravity to perform the separation work during the low-energy phase. This periodic action pattern reduces average energy consumption while maintaining high separation efficiency.
3Manufacturing precision
If electrostatic fields are applied to coalesce water droplets, then separation efficiency improves, but device complexity and energy consumption increase
Solution Approach 1:
The patent divides the separation process into distinct functional segments: an electrostatic coalescence zone with high-voltage electrodes where water droplets merge, and a gravitational separation zone where coalesced droplets settle. This segmentation allows each zone to be optimized independently and simplifies the overall device design by clearly defining the role of each component, reducing unnecessary complexity.
Solution Approach 2:
The patent introduces an intermediary electrostatic field between the water droplets and the separation mechanism. Rather than directly mechanically separating small droplets, the electrostatic field acts as an intermediary that transforms small droplets into larger coalesced droplets, which then become amenable to simple gravitational separation. This intermediary mechanism bridges the gap between the input mixture and the separation process, reducing device complexity.
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 method significantly improves the separation efficiency of water from oil by utilizing electrostatic fields to coalesce water droplets, allowing for effective gravity-assisted separation, reducing energy consumption and enhancing the quality of both water and oil outputs.
Implementation Method 1
passing an oil-in-water mixture through an electrostatic field. Since water is slightly polar, water droplets become polarized by the electrostatic field. Polarized droplets are attracted to each other and move into and coalesce with each other.
Implementation Method 2
water droplets become polarized by the electrostatic field. Polarized droplets are attracted to each other
Implementation Method 3
Larger droplets tend to gravitate downwardly within the mixture and the oil, having portions of the water removed therefrom, tend to gravitate upwardly within the mixture.
Data Source
Figure 1~7
Figure 3~2
Figure 4
AI summary
An apparatus and method for separating water from an oil-and-water mixture includes at least two elongated separator vessels (64, 66) oriented at an incline and connected to one another so that an upwardly flowing oil predominant fluid passes from the first separator vessel (64) to the second separator vessel (66) where further electrostatic separation of water from the oil predominant fluid occurs. Each vessel has an electrode (60) at its upper end preferably connected to a different voltage source. The inlet to each vessel is located relative to the electrode (60) to provide an up flow or a down flow vessel. Additionally, the first vessel (64) may be at a different elevation than the second vessel. An additional vessel may be included with output from the first vessel bypassing the additional vessel, the second vessel, or both. Baffles (134) may be added in the water collection portion (138) of each vessel to reduce turbulence and settling distance.