Centralized Pumping and Energy Recovery in Reverse Osmosis
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Solution Overview
Problem
Reverse osmosis systems face inefficiencies in energy usage due to the need for variable pressure and flow rate adjustments across multiple membrane arrays, leading to increased energy consumption and capital costs, particularly in large-scale operations.
Innovation Solution
A multi-stage reverse osmosis system with a centralized pumping source utilizing a medium pressure pump driven by a variable speed drive, coupled with booster devices that recover energy from the brine stream, allowing for efficient pressure adjustment and independent control of feed flow without individual throttling valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a feed pump is sized to generate the highest possible membrane pressure and then uses a throttle valve to reduce excess pressure, then capital cost is reduced, but energy efficiency is sacrificed
Solution Approach 1:
The feed pumping function is divided into two segments: a feed pump that provides base pressure and flow, and hydraulic pressure boosters that provide additional pressure only where and when needed for specific membrane arrays. This segmentation eliminates the need for a single oversized pump with throttling, reducing energy waste while maintaining capital cost effectiveness.
Solution Approach 2:
Pressure enhancement is applied locally at each membrane array through hydraulic pressure boosters rather than globally through a single oversized feed pump. Each booster receives feed from the common feed line and provides localized pressure augmentation, ensuring energy is consumed only where pressure is actually required for permeate production.
2Adaptability or versatility
If a variable frequency drive is added to operate the feed pump at variable speed, then pressure and flow requirements are matched, but device complexity and power consumption increase
Solution Approach 1:
Hydraulic pressure boosters act as intermediary devices between the common feed line and individual membrane arrays. These boosters use hydraulic power recovery from brine to provide variable pressure enhancement without requiring electrical variable frequency drives, thus reducing device complexity while maintaining adaptability to varying pressure and flow requirements.
3Ease of operation
If multiple individual pumps are used for multiple membrane arrays, then independent control is achieved, but capital cost increases
Solution Approach 1:
Multiple membrane arrays are merged into a common feed system with a single feed pump, reducing capital cost. Hydraulic pressure boosters are then distributed to individual arrays, providing independent pressure control where needed while sharing the common feed line infrastructure, thus achieving a balance between independent control capability and capital cost reduction.
4Ease of operation
If throttle valves are used to regulate flow through membrane arrays, then flow control is achieved, but energy efficiency is reduced
Solution Approach 1:
Hydraulic pressure boosters use hydraulic power recovery from high-pressure brine to provide pressure enhancement for feed water. This hydraulic approach replaces mechanical throttling with a more efficient hydraulic mechanism that recovers energy from the brine stream, thereby improving energy efficiency while maintaining flow and pressure control capability.
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 energy efficiency by reducing energy consumption and capital costs, enabling flexible operation across multiple membrane arrays with improved control over permeate and brine flows, while maintaining optimal membrane performance.
Implementation Method 1
a turbine portion with a turbine input in fluid communication with the brine manifold... High pressure from the brine stream passes through the turbine portion 44 which causes the shaft 46 to rotate
Implementation Method 2
a pump portion having a booster device pump input and a booster device pump output... The pump portion 42 raises the feed pressure in the feed stream 18
Implementation Method 3
A membrane is used that restricts the flow of dissolved solids therethrough... the membrane array 12 that generates a permeate stream 14 and a brine stream 16 from a feed stream 18
Data Source
Figure 1~4
Figure 5~6
Figure 7~8b
AI summary
A reverse osmosis system includes a plurality of feed pumps (20) each having a feed pump input and a feed pump output, an input manifold (80) in fluid communication with the feed pump inputs and a membrane feed manifold (82) in fluid communication with the feed pump output. The system also includes a plurality of membrane chambers (12) each in fluid communication with the membrane feed manifold and generating a permeate output and a brine output, each brine output in fluid communication with a brine manifold (104). The system further includes a plurality of booster, devices (212) each having a turbine portion (214) with a turbine input in fluid communication -with the brine manifold and a pump portion (210) having a booster device pump input and a booster device pump output, each booster device pump output in fluid communication with the membrane feed manifold (82). The system includes a pump input manifold (222) in fluid communication with the booster device pump input. The system also includes a medium pressure pump (200) in fluid communication with the input manifold (80) and the pump input manifold (222) '.