Reverse osmosis treatment system for recovering energy generated both at brine and permeate sides during seawater desalination

Patent metadata

Field	Value
Publication number	US-10427101-B2
Application number	US-201615385044-A
Country	US
Kind code	B2
Filing date	Dec 20, 2016
Priority date	Dec 21, 2015
Publication date	Oct 1, 2019
Grant date	Oct 1, 2019

Abstract

Provided is a reverse osmosis treatment system capable of simultaneously and efficiently recovering energy generated both at brine and permeate sides. The system comprises a branched portion configured to divide second to-be-treated water into third and fourth to-be-treated water; a high-pressure pump configured to pressurize the third to-be-treated water thereby to feed fifth to-be-treated water having a higher pressure than the to-be-treated water before divided; a displacement type of first energy recovery device configured to exchange pressures between the fourth to-be-treated water and brine thus separated by a reverse osmosis treatment device, thereby to produce sixth to-be-treated water having a higher pressure than the fourth one; and a second energy recovery device configured to raise a pressure of the third to-be-treated water located at a downstream side of the branched portion with a pressure of first permeate thus separated by the reverse osmosis treatment device.

First claim

What is claimed is:

1. A reverse osmosis treatment system comprising:
a reverse osmosis treatment device configured to separate first to-be-treated water into permeate and brine via reverse osmosis;
a branched portion at which second to-be-treated water is divided into third to-be-treated water and fourth to-be-treated water;
a first pump configured to pressurize the third to-be-treated water thus divided, thereby to feed fifth to-be-treated water having a higher pressure than to-be-treated water before divided into the third to-be-treated water;
a first energy recovery device configured to exchange pressures between the fourth to-be-treated water thus divided and the brine thus separated by the reverse osmosis treatment device, thereby to produce sixth to-be-treated water having a higher pressure than the fourth to-be-treated water;
a merging portion at which the fifth to-be-treated water and the sixth to-be-treated water are merged to produce the first to-be-treated water; and
a second energy recovery device configured to raise a pressure of the third to-be-treated water located at a downstream side of the branched portion with a pressure of the permeate thus separated by the reverse osmosis treatment device.

2. The reverse osmosis treatment system described in claim 1 , wherein the second energy recovery device is configured to raise the pressure of the third to-be-treated water located at the downstream side of the branched portion by rotating a turbine or a Pelton wheel with a pressure of the permeate.

3. The reverse osmosis treatment system described in claim 2 , wherein the second energy recovery device is configured to raise a pressure of the third to-be-treated water before being fed by the first pump.

4. The reverse osmosis treatment system described in claim 1 , wherein the second energy recovery device is configured to raise a pressure of the third to-be-treated water before being merged at the merging portion.

5. The reverse osmosis treatment system described in claim 1 , wherein
the first pump includes a motor configured to drive a rotor of the pump,
the second energy recovery device includes a turbine or a Pelton wheel fixed on an axis of the motor, and
the turbine or the Pelton wheel is rotated with a pressure of the permeate.

Assignees

• Hitachi Ltd

Inventors

• MIYAKAWA Hiroki
• Kitamura Kotaro
• Matsuura Masayuki
• Oshikiri Takanori
• Okawa Yusuke

Classifications

• B01D2317/022

  Reject series · CPC title

• C02F2209/03

  Pressure · CPC title

• F01L5/02

  with other than cylindrical, sleeve or part annularly shaped valves, e.g. with flat-type valves · CPC title

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• F01D5/02

  Blade-carrying members, e.g. rotors (rotors of non-bladed type F01D1/34; stators F01D9/00 {; selecting particular materials F01D5/28}) · CPC title