Multi-Stage Centrifugal Pump Coalescing Design
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Solution Overview
Problem
Existing centrifugal pumps break up dispersed oil droplets to sizes that are not feasible for effective separation in downstream equipment, reducing separation efficiency, and lack a design that simultaneously provides high pressure boosting, high flow rate, and low droplet break-up while maintaining coalescing effects.
Innovation Solution
A multi-stage centrifugal pump design where the last stage is modified to increase equilibrium droplet size, with smaller impeller diameters and larger diffuser cross-section areas, reducing shear and enhancing coalescence by increasing fluid residence time and turbulence, allowing for high pressure boosting and low droplet break-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If conventional centrifugal pumps are used to provide high pressure boosting and high flow rate, then pressure and flow requirements are met, but dispersed oil droplets are broken up to sizes not feasible for effective separation
Solution Approach 1:
The pump is divided into multiple stages, with each stage having different impeller designs. The first stages use impellers optimized for pressure boosting, while the last stage uses a modified impeller with larger eye diameter and fewer blades optimized for coalescing and minimizing droplet break-up.
Solution Approach 2:
Different parts of the pump system have different functional characteristics. The upstream stages have impellers designed for high pressure generation, while the downstream stage has an impeller specifically designed for low shear and coalescing, creating local quality variations throughout the system.
2Stress or pressure
If the number of pump stages is increased to provide higher pressure boosting, then pressure requirements are met, but the cumulative shear effect increases and droplet size decreases
Solution Approach 1:
The multi-stage pump is segmented into functionally different stages. The first stages handle pressure boosting, while the final stage is dedicated to coalescing and droplet size maintenance, allowing the system to achieve high pressure without sacrificing separation efficiency.
Solution Approach 2:
The impeller parameters are changed in the last stage compared to upstream stages. The last stage impeller has a larger eye diameter, fewer blades, and different blade geometry, changing the local flow characteristics to reduce shear and promote coalescing despite the cumulative pressure from multiple stages.
3Productivity
If chemicals such as flocculants and coalescers are added to increase droplet size, then separation efficiency improves, but operational complexity and chemical usage increase
Solution Approach 1:
The pump system performs the coalescing function itself through its mechanical design. The modified last stage impeller creates flow conditions that naturally promote droplet coalescence without requiring external chemicals, making the system self-sufficient for the coalescing task.
Solution Approach 2:
The coalescing function is extracted from the chemical domain and implemented through mechanical means. Instead of using chemical coalescers, the pump's hydraulic design inherently provides coalescing through the specially designed last stage impeller geometry and flow patterns.
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 pump achieves a larger coalescing effect, maintaining or increasing droplet size while providing high pressure and flow rates, improving downstream separation efficiency and reducing the need for additional chemicals or equipment.
Implementation Method 1
The invention relates to pumps for pressure boosting. More specifically, the invention relates to centrifugal pumps
Implementation Method 2
enhancing coalescence by increasing fluid residence time and turbulence
Implementation Method 3
low shear pumping
Data Source
AI summary
The invention provides a centrifugal pump, distinctive in that the pump comprises two or more stages; the last stage in the direction of flow has been adapted so that it provides a larger equilibrium droplet size than the upstream stages. Method of designing the pump and use of the pump.