Planar Diffuser for SAGD Skim Tank Turbulence Reduction
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Solution Overview
Problem
Existing skim tanks in Steam-Assisted Gravity Drainage (SAGD) processes are inefficient in removing residual oil from produced water, leading to costly production shutdowns and maintenance due to high turbulence and short-circuiting, which reduces the residence time of oil droplets and results in undesirably high residual oil in the exhausted water.
Innovation Solution
The use of a diffuser system that expands the cross-sectional area of the oil-containing liquid flow linearly rather than conically, minimizing vertical divergence and turbulence, combined with an intake manifold that equalizes pressure across multiple conduits to distribute the flow uniformly, thereby reducing turbulence and increasing residence time within the skim tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional conical diffuser is used to expand the flow cross-section, then the flow area increases, but vertical divergence and turbulence increase, reducing residence time
Solution Approach 1:
The diffuser is divided into multiple separate diffuser elements or zones rather than a single conical structure. This segmentation allows each element to expand flow in a controlled manner, reducing vertical divergence while collectively achieving the required cross-sectional area expansion, thereby maintaining longer residence time
Solution Approach 2:
The diffuser design transitions from a conventional conical (3D) structure to a planar or flattened geometry. This dimensional change allows the flow to expand primarily in the horizontal plane rather than vertically, reducing vertical divergence and turbulence while still achieving the necessary cross-sectional area increase
2Productivity
If high flow velocity is maintained to increase productivity, then more liquid is processed, but turbulence increases and residence time decreases
Solution Approach 1:
The inlet flow is divided into multiple separate streams through multiple diffuser elements, allowing each stream to be processed at lower velocity while collectively maintaining high overall productivity. This segmentation reduces turbulence in each individual flow path while preserving total throughput capacity
Solution Approach 2:
The flow expansion occurs primarily in the horizontal dimension rather than vertically, allowing increased cross-sectional area without proportionally increasing flow velocity. This dimensional shift enables higher productivity while maintaining lower velocities and longer residence times
3Loss of time
If the diffuser expands flow area to reduce velocity, then residence time increases, but vertical divergence increases
Solution Approach 1:
The diffuser geometry is changed from a conical shape that expands in all dimensions to a planar configuration that expands primarily in the horizontal plane. This dimensional change achieves velocity reduction through area expansion while minimizing vertical divergence of the flow stream
Solution Approach 2:
Different regions of the diffuser are designed with different expansion characteristics - the planar diffuser elements are configured to provide controlled local expansion that reduces velocity without creating excessive vertical divergence, optimizing the balance between residence time and flow shape
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 configuration enhances the efficiency of oil separation by increasing the residence time of liquid in the skim tank, reducing turbulence, and improving the removal of residual oil, resulting in higher oil removal efficiency and lower maintenance costs.
Implementation Method 1
Oil droplets have a lower density than water and tend to rise in water due to buoyancy whereas denser particles tend to settle
Implementation Method 2
minimizing vertical divergence and turbulence, combined with an intake manifold that equalizes pressure across multiple conduits to distribute the flow uniformly, thereby reducing turbulence
Implementation Method 3
Oil droplets have a lower density than water and tend to rise in water due to buoyancy whereas denser particles tend to settle, forming a layer at the bottom of the tank
Implementation Method 4
A skim tank is effectively a very large gravity or buoyancy separation tank
Implementation Method 5
Stokes' law is valid when the fluid that the droplets are rising through is characterized by laminar flow
Data Source
AI summary
Apparatus and methods for conveying a flow of oil-containing liquid into an oil separation skim tank, and a skim tank incorporating such apparatus and methods, are disclosed. One such apparatus includes at least one diffuser, the diffuser defining an intake opening configured to receive the flow of oil-containing liquid and an exhaust opening configured to convey the flow of oil-containing liquid into the skim tank. The diffuser is configured to cause the flow of oil-containing liquid to have a greater horizontal width at the exhaust opening than at the intake opening, while minimizing vertical divergence of the flow at the exhaust opening.