Reverse Osmosis Membrane Cleaning via Generator-Drive Pressure Pulses
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Solution Overview
Problem
Existing systems for reverse osmosis face challenges in efficiently addressing the membrane fouling process, particularly in the context of chemical and physical cleaning, which involves sophisticated control systems that are prone to mechanical failure and malfunction, and the need for improved energy efficiency and effective cleaning performance.
Innovation Solution
A system for reverse osmosis that employs a generator drive for energy recovery and membrane cleaning, utilizing a high-pressure chamber and low-pressure chamber separated by a membrane, with a generator drive connected to a variable frequency drive to modulate shaft speed and control fluid flow, thereby inducing oscillations for effective cleaning without relying on valves or pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If valves are used for pressure modulation in RO systems, then membrane cleaning can be achieved through pressure pulses, but system complexity increases and reliability decreases due to mechanical wear and control system requirements
Solution Approach 1:
The patent removes valves from the RO system entirely, extracting the pressure modulation function from mechanical valve components. Instead of using valves to create pressure pulses for membrane cleaning, the system uses a centrifugal pump operating at variable speeds to directly generate the necessary pressure variations, eliminating the need for complex valve control systems and improving reliability.
Solution Approach 2:
The patent replaces the mechanical valve-based pressure modulation system with an electromechanical centrifugal pump system controlled by a variable frequency drive. This substitution eliminates mechanical wear from valve components while maintaining the ability to generate pressure pulses for effective membrane cleaning, reducing both complexity and failure points.
2Productivity
If chemical cleaning processes are used for membrane maintenance, then fouling can be removed, but production downtime increases and production capacity is constrained
Solution Approach 1:
The patent implements periodic pressure pulse action through variable speed centrifugal pump operation to continuously clean the membrane surface during normal production. By applying oscillating pressure pulses at optimized frequencies, the system prevents fouling accumulation and removes deposits in real-time, eliminating the need for periodic chemical cleaning shutdowns and maintaining continuous production capacity.
Solution Approach 2:
The patent enables continuous membrane cleaning action during production operation through the centrifugal pump's variable speed capability. The pump maintains optimal flow and pressure conditions continuously, applying cleaning pressure pulses without interrupting the RO process, thereby eliminating production downtime associated with chemical cleaning cycles.
3Device complexity
If centrifugal pumps are used for pressure modulation, then system simplicity improves, but energy efficiency decreases due to the pump's inherent power consumption
Solution Approach 1:
The patent makes the centrifugal pump serve multiple functions simultaneously: it provides the necessary feed pressure for the RO system, generates pressure pulses for membrane cleaning, and operates at variable speeds to optimize both energy efficiency and cleaning performance. This multi-functionality eliminates the need for separate pressure modulation devices while maximizing energy utilization.
Solution Approach 2:
The patent employs dynamic speed control of the centrifugal pump through a variable frequency drive to optimize energy consumption. By adjusting the pump speed according to real-time system requirements and membrane cleaning needs, the system achieves energy efficiency while maintaining the simplicity of using a single pump for both pressurization and cleaning functions.
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 system achieves efficient energy recovery and optimal cleaning performance by reducing system downtime and prolonging component lifespan, while minimizing the need for chemical processes and enhancing membrane integrity.
Implementation Method 1
a generator drive for energy recovery... The generator drive is configured for recuperating energy from a fluid flow based on a shaft speed of the generator drive
Implementation Method 2
modulating the shaft speed to generate pressure pulses in the fluid flow... inducing oscillations for effective cleaning
Implementation Method 3
inducing oscillations of the membrane based on the modulated shaft speed... oscillated membrane deformation to shake off the deposits
Implementation Method 4
In the RO process, the fluid to be treated is fed under a certain pressure into the feed chamber of a membrane unit... and then penetrates the membrane to leave the membrane unit as permeate
Implementation Method 5
generates a controlled membrane deformation to induce shear stresses at the foulant-membrane interface, which facilitates the detachment or removal of the foulants from the membrane
Data Source
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AI summary
The present disclosure relates to a system (100) for reverse osmosis, RO, comprising a first membrane unit (10) and a first generator drive (G1). The first membrane unit (10) comprises a first feed inlet (11), a first concentrate outlet (12), a first permeate outlet (13), and a first membrane (14). The first generator drive (G1) is fluidly connected to and disposed downstream of the first membrane unit (10). The first generator drive (G1) is configured for recuperating energy from a first fluid flow effluent from the first membrane unit (10) based on a first shaft speed of the first generator drive (G1) and for inducing oscillations of the first membrane (14) by modulating the first shaft speed to generate pressure pulses in the first fluid flow. The present disclosure further relates to a method of operating the system (100), a generator drive, and the use of a generator drive for inducing oscillations of one or more membranes in the system (100).