Oscillating Partition Pump for Desalination Energy Recovery
Solution Overview
Problem
Conventional reverse osmosis systems require significant energy to bring feed water to operating pressure, and existing energy recovery methods are inefficient and unable to recover all lost energy, with complex designs and fixed recovery rates making them unsuitable for retrofitting or varying volume ratios.
Innovation Solution
A pump assembly with two interconnected pumps, each with a bore and longitudinal partition members that oscillate to vary sub-chamber volumes, allowing for efficient water flow and pressure intensification, coupled with a reverse osmosis membrane to desalinate water, reducing energy requirements and simplifying system design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high pressure pump is used to bring feed water to operating pressure, then reverse osmosis process can be achieved, but significant amounts of energy are required
Solution Approach 1:
The pump assembly is divided into two separate pumps: a first pump that delivers feed water to the reverse osmosis membrane at high pressure, and a second pump that recovers and reuses the brine stream. This segmentation allows independent optimization of each pump's function, with the second pump recovering energy that would otherwise be wasted, thereby reducing overall energy consumption while maintaining reliable RO process operation.
Solution Approach 2:
The invention recovers the brine stream (feed water that has passed through the RO membrane) and reuses it by directing it back to the first pump inlet. This recovery mechanism captures the energy and fluid that would normally be discarded, reducing the total energy required to maintain the RO process by approximately 50% compared to conventional systems.
2Loss of energy
If energy recovery methods are implemented, then some energy loss can be recovered, but more energy than needed is supplied and not all energy is recovered
Solution Approach 1:
The second pump is designed to automatically recover and reuse the brine stream without requiring additional external energy input beyond what is already present in the system. The recovered brine is fed back to the first pump inlet, creating a self-sustaining cycle that reduces overall energy demand while avoiding the problem of supplying more energy than needed.
3Productivity
If dual chamber pump with piston is used, then feed water can be pumped towards RO membrane, but large number of parts are required
Solution Approach 1:
The pump assembly is segmented into two independent but coordinated pumps, each with its own piston and chamber. This segmentation allows for simpler individual components that can be manufactured and maintained more easily, while collectively achieving the required water delivery productivity. The first pump handles feed water delivery and the second pump handles brine recovery, with each unit being relatively simple in design.
Solution Approach 2:
The pump assembly design allows both pumps to serve multiple functions: the first pump delivers feed water to the RO membrane while the second pump recovers brine and feeds it back to the first pump inlet. This multi-functionality reduces the need for separate dedicated components for each function, thereby reducing the overall number of parts while maintaining high productivity.
4Ease of operation
If fixed recovery rate pump is used, then pump operation is simplified, but volume recovery rate cannot be altered
Solution Approach 1:
The pump assembly incorporates variable displacement pistons that can adjust their volume during operation. This dynamic capability allows the recovery rate to be varied by changing the piston displacement volume, providing adaptability to different operational requirements while maintaining relatively simple pump operation. The system can be adjusted to match different feed water flow rates and recovery rate requirements.
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 solution significantly reduces energy consumption, simplifies the system with fewer parts, and allows for adaptable recovery rates, making it suitable for various applications including sea water desalination, brackish water treatment, and nanofiltration, while avoiding over-production pressures that can harm membranes.
Implementation Method 1
Reverse osmosis is a phenomenon that was first considered in the 1950's as a method for separating the components of a solution. In the reverse osmosis process the solution to be separated is passed under high pressure past a reverse osmosis membrane enclosed within a higher pressure chamber. The reverse osmosis membrane allows a certain percentage of the solution to pass through the membrane as potable water, while rejecting the various impurities within the water, including salt.
Implementation Method 2
As the piston moves feed water is driven from one side of the piston to the other via the RO membrane. As the feed water enters the side of the piston containing the ram, the pressure of the water is intensified by the volume of the ram. This intensified pressure of the feed water causes the RO process to take place.
Data Source
AI summary
A pump assembly to move water past a reverse osmosis membrane, the pump assembly having a first pump and a second pump each including a bore having a longitudinal axis and surrounding a chamber. First and second partition members extend longitudinally of the chamber. The second partition is moveable relative to the first partition member, and divides the chamber into a first sub chamber and a second sub chamber. A shaft is attached to the second member to cause angular movement thereof about the axis to change the volumes of the sub chambers. End caps are fitted to ends of each chamber to contain pressure, and ducting is provided to provide for the flow of water. The shaft of the first pump is coupled to the shaft of the second pump so that the first pump second partition angularly oscillates in phase with the second pump second partition.