Flotation Weirs and Hydraulic Oil Removal
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Solution Overview
Problem
Current flotation apparatuses have suboptimal separation efficiency for removing oil from water, with significant amounts of oil remaining in the purified water due to inefficient aggregation formation and sticky oil-froth layers that are not properly removed.
Innovation Solution
A flotation apparatus with a combination of underflow and overflow weirs, where the overflow weir is arranged downstream, and a hydraulic means to push the formed oil-froth layer into removal means, ensuring efficient gas bubble adherence and complete removal of oil droplets, achieving a separation efficiency of at least 90%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional flotation apparatuses are used for separating oil from water, then the separation process can be performed, but the separation efficiency is suboptimal with significant amounts of oil remaining in the purified water
Solution Approach 1:
The flotation apparatus is divided into multiple longitudinal cell sections separated by underflow weirs, creating distinct zones for different separation stages. This segmentation allows optimized gas injection in specific zones and improves overall separation efficiency by handling different flow regimes in different sections.
Solution Approach 2:
Gas injection means are positioned specifically in the channel between underflow and overflow weirs where flow conditions are most favorable for bubble-droplet aggregation. The hydraulic means are positioned at specific locations to push oil-froth layers into removal means. This localized placement of functional elements maximizes separation efficiency in critical zones.
2Productivity
If conventional flotation apparatuses are used, then oil-froth layers form on the water level, but the sticky oil-froth layers are not properly removed and water flow is disturbed
Solution Approach 1:
Hydraulic means are used to eject a stream of liquid or gas onto the water level to push the oil-froth layer into removal means. This hydraulic approach provides controlled, disturbance-free removal of sticky oil-froth layers compared to mechanical scraping methods, maintaining both productivity and water quality.
3Quantity of substance
If gas bubbles are introduced into the dispersion, then oil droplet aggregation occurs, but the aggregation formation is inefficient and not all oil droplets rise to the surface
Solution Approach 1:
Gas injection is positioned in the channel between underflow and overflow weirs where dispersion first enters the flotation zone. This preliminary gas injection occurs at the optimal location before droplets enter the main flotation section, maximizing aggregation formation efficiency and ensuring all oil droplets have opportunity to attach to bubbles before reaching the surface.
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
The apparatus effectively removes over 90% of oil droplets from water, with a preferred efficiency of 98%, by ensuring efficient gas bubble adherence and complete removal of the oil-froth layer without disturbing the water flow.
Implementation Method 1
Flotation utilizes the different surface tension of solid materials or of hydrophobic liquids, such as oil, relative to the hydrophilic liquid of the continuous phase, such as water
Implementation Method 2
The gas bubbles adhere to the dispersed phase, which leads to aggregates of dispersed phase particles and/or dispersed phase droplets with attached gas bubbles, wherein the aggregates have - on account of the adhered gas bubbles - a lower density than the continuous phase. Due to this, the aggregates rise or float up, respectively, to the surface
Implementation Method 3
hydraulic means for ejecting a stream of liquid, a stream of gas or a stream of liquid and gas onto the liquid level of the vessel and/or onto the second fraction being formed during the operation of the flotation apparatus on the liquid level of the vessel
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to a flotation apparatus for separating in particular oil from a dispersion containing water as continuous phase and oil as dispersed phase, the apparatus comprising a vessel comprising in its longitudinal direction one or more longitudinal cell sections, wherein at least one of the one or more longitudinal cell sections comprises: - at least one underflow weir, - at least one overflow weir, wherein the overflow weir is located in a distance to and displaced in the direction to the downstream end of the vessel from the underflow weir, - at least one gas injection means being located vertically below the underflow weir or being located in the channel formed between the underflow weir and the overflow weir, - at least one removal means for removing the second fraction being formed during the operation of the flotation apparatus on the liquid level from the liquid level and - at least one hydraulic means for hydraulically pushing the second fraction being formed during the operation of the flotation apparatus on the liquid level of the vessel into the removal means by means of a liquid stream, by means of a liquid/gas stream and/or by means of a gas stream, wherein the respective liquid stream, liquid/gas stream and/or gas stream is ejected by the hydraulic means onto the liquid level of the vessel and/or onto the second fraction being formed during the operation of the flotation apparatus on the liquid level.