# US 2014/0151278 A1 · Multi-stage seawater desalination apparatus and operation control method of multi-stage seawater desalination apparatus

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2014/0151278 A1
- Document ID: US20140151278A1
- Status: Published application
- Kind: A1
- Application number: 14/175,309
- Filed: 2014-02-07
- Published: 2014-06-05
- Earliest claimed: 2008-11-27
- Assignees: Mitsubishi Heavy Industries, Ltd.
- Applicants: Mitsubishi Heavy Industries, Ltd.
- Inventors: Kazuhisa Takeuchi; Yoshiaki Ito; Kenji Tanaka; Hideo Iwahashi; Katsunori Matsui; Takayoshi Hori
- Web page: https://patentgrep.com/patent/US20140151278A1

## CPC

- C02F 1/441: {by reverse osmosis}
- B01D 61/025: {Reverse osmosis; Hyperfiltration}
- B01D 61/026: {comprising multiple reverse osmosis steps}
- B01D 61/12: Controlling or regulating
- B01D 2311/14: Pressure control
- B01D 2317/025: Permeate series
- C02F 2103/08: Seawater, e.g. for desalination
- C02F 2209/03: Pressure
- C02F 2301/08: Multistage treatments, e.g. repetition of the same process step under different conditions
- Y02A 20/131: Reverse-osmosis
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE

## Abstract

A high-pressure pump P1 that increases the pressure of raw water, a high-pressure reverse osmosis device including a high-pressure reverse osmosis membrane for concentrating a salt content in high-pressure feed water, a first drain valve mounted on a permeated water line for supplying the permeated water downstream and temporarily draining permeated water of an initial start-up from a discharge line, a low-pressure pump that is mounted on a permeated water line provided downstream of the first drain valve and reduces the pressure of the permeated water, a low-pressure reverse osmosis device including a low-pressure reverse osmosis membrane for concentrating a salt content in low-pressure feed water, and a second drain valve mounted on a discharge line at the concentrated water side of the low-pressure reverse osmosis device that temporarily discharges the low-pressure feed water of the initial start-up supplied to the low-pressure reverse osmosis device.

## Claims

### Claim 1

A multi-stage seawater desalination apparatus comprising:
a high-pressure pump that is mounted on a raw water line through which raw water is supplied, and increases pressure of the raw water to a predetermined high pressure;
a high-pressure reverse osmosis device that includes a high-pressure reverse osmosis membrane for concentrating a salt content in high-pressure feed water whose pressure is increased by the high-pressure pump;
a first drain valve that is mounted on a permeated water line through which permeated water that has passed through the high-pressure reverse osmosis device is supplied downstream, and temporarily drains the permeated water of an initial start-up;
a low-pressure pump that is mounted on the permeated water line provided downstream of the first drain valve, and reduces pressure of the permeated water to a predetermined low pressure;
a low-pressure reverse osmosis device that includes a low-pressure reverse osmosis membrane for concentrating a salt content in low-pressure feed water whose pressure is reduced by the low-pressure pump; and
a second drain valve that is mounted on a discharge line on a concentrated water side of the low-pressure reverse osmosis device, and temporarily discharges the low-pressure feed water of the initial start-up supplied to the low-pressure reverse osmosis device.

### Claim 2 (depends on 1)

The multi-stage seawater desalination apparatus according to claim 1, further comprising
a plurality of the low-pressure reverse osmosis devices, wherein
the second drain valve is mounted on the discharge line at the concentrated water side of each of the low-pressure reverse osmosis devices, and temporarily discharges the low-pressure feed water of the initial start-up supplied to the low-pressure reverse osmosis devices.

### Claim 3 (depends on 1)

The multi-stage seawater desalination apparatus according to claim 1, further comprising a returned concentrated water line that returns the concentrated water from the low-pressure reverse osmosis device upstream.

### Claim 4 (depends on 1)

The multi-stage seawater desalination apparatus according to claim 1, wherein the high-pressure reverse osmosis device is a membrane with chlorine-resistance.