Seawater desalination pressurization and energy recovery integrated method and device using membrane method

Abstract

A membrane seawater desalination pressurization and energy recovery integrated method. Piston rods of single-rod piston-type seawater cylinders are connected with single-rod piston-type hydraulic cylinders to form two or more than two working combined bodies which operate alternately. In a process that the hydraulic cylinders drive the seawater cylinders to move back and forth, one piston cavity of a seawater cylinder sucks high pressure strong brine in the process of moving forward and drains the high pressure strong brine in the returning process; and the other piston cavity of the seawater cylinder sucks raw seawater in the returning process, pressurizes the raw seawater in the process of moving forward and continuously and stably outputs the pressurized high pressure raw seawater to a reverse osmosis membrane module. Meanwhile, a membrane seawater desalination pressurization and energy recovery integrated device is further disclosed.

Description

technical field [0001] The invention relates to a high-pressure pump, an energy recovery device and a booster pump required for reverse osmosis membrane seawater desalination, in particular to a device integrating the high-pressure pump, the booster pump and the energy recovery system. Background technique [0002] Desalination of seawater is a method to solve the shortage of fresh water resources in the world. There are two commonly used methods: thermal method and membrane method. Among them, membrane seawater desalination technology using reverse osmosis membrane has been widely used because of its low cost and low energy consumption, and has gradually become the mainstream. [0003] In the seawater desalination system, the pretreated seawater with low salt content entering the desalination system is raw seawater, which is pressurized to form high-pressure raw seawater, part of which passes through the reverse osmosis membrane group and becomes low-pressure fresh water, a...

AI Technical Summary

Problems solved by technology

The sum of the two costs accounts for about 1 / 3 of the total investment cost, the electricity consumption accounts for more than 2 / 3 of the total electricity consumption, and the electricity consumption cost accounts for more than 1 / 3 of the operating cost. The power consumption is 35kwh, and under the existing membrane technology level, the limit power consumption should be around 2.5kwh, and there is still 1 / 3 of energy-saving space

The other is based on the principle of pressure exchange, that is, in the cylindrical cylinder, through the flow distribution mechanism, the high-pressure concentrated brine directly transfers the pressure potential energy to the original seawater, the transfer efficiency is very high, and the energy recovery efficiency can reach more than 90%; according to The flow distribution methods are different, and can be further subdivided into the structure of valve flow distribution without piston on the end face of the rotating cylinder and the valve flow distribution structure with piston on the fixed cylinder; The structure is simple but there will be 25% blending, which requires an independent booster pump, which will reduce the overall efficiency; and the valve distribution structure with pistons in the fixed cylinder, no need to set up a booster pump, the efficiency can be higher, but its control Organization is more complex

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