System and method for controlling an integrated pump and energy recovery system

Abstract

A system for controlling an integrated pump and energy recovery system is disclosed. The processor-based device is configured to receive a position signal representative of a measured position of a piston assembly movable between a top dead center and a bottom dead center of a hydraulic cylinder and a pumping cylinder, from the position sensor. The processor-based device is also configured to receive a pressure signal representative of a measured pressure of at least one of a fluid medium fed from the pumping cylinder to a filtering device, a hydraulic fluid fed from the hydraulic pump to the hydraulic cylinder, from the pressure sensing unit. The processor-based device is further configured to generate a control signal based on the position signal and the pressure signal, and transmit the control signal to the hydraulic power unit to control measured position of the piston assembly and a pressure of the fluid medium.

Description

BACKGROUND[0001]Typically, an integrated pump and energy recovery system is used to pump an input stream of fluid for purification through a membrane or filter, such as a reverse osmosis membrane, at a higher pressure. A stream of brine or other concentrated unpurified material is then discharged under pressure from such a membrane or filter. Typically energy is recovered from the discharge stream still under pressure, and then such recovered energy is used for a useful purpose, for example, to reduce the amount of energy that the pump would otherwise have to expend in order to pump the input stream of fluid into the system, thereby making operation of the purification system more efficient.[0002]When a semi-permeable membrane divides two fluids of different salinities, osmosis occurs. To achieve equilibrium of the chemical potential across the membrane, liquid flows through the membrane into the more concentrated solution. This flow continues until concentrations on either side of ...

AI Technical Summary

Benefits of technology

The patent describes a system for controlling an integrated pump and energy recovery system. The system includes a processor-based device that receives position and pressure signals from sensors and uses them to generate a control signal that is sent to the pump to control the position of the piston and the pressure of the fluid. The technical effect of this system is improved control over the movement and pressure of the fluid, leading to more efficient and effective energy recovery.

Problems solved by technology

In an integrated pump and energy recovery system using a plurality of piston-cylinder arrangements and valves for pumping the fluid medium, there are issues associated with generation of pressure ripples in the high pressure feed-water fed to a reverse osmosis (RO) membrane stack and variation in total flow of the feed-water per cycle.

Such issues affect the RO membrane stack.

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