# US 10,118,836 B2 · Apparatus, use of apparatus and process for desalination of water

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- Number: US 10,118,836 B2
- Document ID: US10118836B2
- Status: Granted
- Kind: B2
- Application number: 14/419,591
- Filed: 2013-02-13
- Published: 2015-07-30
- Granted: 2018-11-06
- Earliest claimed: 2012-08-08
- Assignees: Sulzer Chemtech AG
- Applicants: Sulzer Chemtech AG
- Inventors: Severine Dette; Mansour M. M. Ahmad; Manfred Stepanski
- Web page: https://patentgrep.com/patent/US10118836B2

## CPC

- C02F 1/08: Thin film evaporation
- B01D 9/0027: {by means of conveying fluid, e.g. spray-crystallisation (spray-drying F26B)}
- B01D 9/0059: {General arrangements of crystallisation plant, e.g. flow sheets}
- B01D 61/025: {Reverse osmosis; Hyperfiltration}
- B01D 61/08: Apparatus therefor
- C02F 1/22: by freezing
- C02F 1/441: {by reverse osmosis}
- B01D 61/02: Reverse osmosis; Hyperfiltration {; Nanofiltration}
- B01D 61/10: Accessories; Auxiliary operations
- B01D 2311/2673: Evaporation
- C02F 1/008: {Control or steering systems not provided for elsewhere in subclass C02F}
- C02F 2103/08: Seawater, e.g. for desalination
- C02F 2103/10: from quarries or from mining activities
- C02F 2201/002: Construction details of the apparatus
- C02F 2209/001: Upstream control, i.e. monitoring for predictive control
- C02F 2209/02: Temperature
- C02F 2209/05: Conductivity or salinity
- C02F 2301/08: Multistage treatments, e.g. repetition of the same process step under different conditions
- C02F 2303/10: Energy recovery
- C02F 2303/20: Prevention of biofouling
- C02F 2303/22: Eliminating or preventing deposits, scale removal, scale prevention (C02F1/042, C02F1/4602, C02F5/00 take precedence)
- Y02A 20/124: Water desalination
- Y02A 20/131: Reverse-osmosis
- Y02W 10/30: Wastewater or sewage treatment systems using renewable energies
- 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
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT

## Abstract

A process for desalinating water is disclosed. The process comprises the steps of passing a feed stream of saline solution 2′ in a first desalination step through a reverse osmosis membrane desalination plant 3′ comprising at least one reverse osmosis desalination unit 4′ to form a first product water stream 5′ having a reduced salt concentration relative to that of the feed stream of saline solution 2′ and a first byproduct stream 6′ having an increased salt concentration relative to that of the feed stream of saline solution 2′ characterized in that the first byproduct stream 6′ is passed in a second desalination step through a falling film crystallization unit 7 to form a second product water stream 8 having a reduced salt concentration relative to that of the first byproduct stream 6′ and a second byproduct stream 9 having an increased salt concentration relative to that of the first byproduct stream 6′. The invention further relates to an apparatus 1 for carrying out said process. The present invention further relates also to the use of the process or apparatus 1 for the reduction of the volume of the first byproduct stream 6′ of a reverse osmosis membrane desalination plant 3′, preferably an in-land desalination plant 3′, or in a device or plant or process for producing desalinated water, for salt production, for co-production of power and desalinated water, or for air conditioning.

## Claims

### Claim 1

A process for desalinating water comprising the steps of:
passing a feed stream of saline solution in a first desalination step through a reverse osmosis membrane desalination plant comprising at least one reverse osmosis desalination unit to form a first product water stream having a reduced salt concentration relative to that of the feed stream of saline solution and a first byproduct stream having an increased salt concentration relative to that of the feed stream of saline solution,
wherein the first byproduct stream is passed in a second desalination step through a first falling film crystallization unit to form a second product water stream having a reduced salt concentration relative to that of the first byproduct stream and a second byproduct stream having an increased salt concentration relative to that of the first byproduct stream,
wherein the salt concentration of the first byproduct stream is between 3 to 7 weight %,
wherein the second byproduct stream is passed in a third desalination step through a static crystallization unit to form a third product water stream having a reduced salt concentration relative to that of the second byproduct stream and a third byproduct stream having an increased salt concentration relative to that of the second byproduct stream,
wherein the third product water stream is fed into the first byproduct stream, and
wherein the second byproduct stream is crystallized in the static crystallization unit at a temperature between about −4 to about −13° C.

### Claim 2 (depends on 1)

The process of claim 1, wherein the first byproduct stream is crystallized in the first falling film crystallization unit at a temperature between about −1 to about −4° C.

### Claim 3 (depends on 1)

The process of claim 1, wherein the salt concentration of the second byproduct stream is between about 8 to about 18 weight %.

### Claim 4 (depends on 1)

The process of claim 1, wherein the second desalination step in the first falling film crystallization unit and/or the third desalination step in the static crystallization unit or the first falling film crystallization unit or the second falling film crystallization unit comprises a sweating stage in which a byproduct is removed from a product by means of partial melting of a crystal within the first falling film crystallization unit or the static crystallization unit or the second falling film crystallization unit.

### Claim 5 (depends on 1)

The process of claim 1, wherein the steps occur in a reverse osmosis membrane desalination plant, or in a device or plant or process for producing desalinated water, for salt production, for co-production of power and desalinated water, or for air conditioning.

### Claim 6

An apparatus for carrying out a process for desalinating water, the apparatus comprising:
a reverse osmosis membrane desalination plant comprising at least one reverse osmosis desalination unit having an inlet for a feed stream of saline solution, an outlet for a first product water stream, an outlet for a first byproduct stream,
wherein the outlet for a first byproduct stream is in fluid communication with an inlet of a first falling film crystallization unit having an outlet for a second product water stream, and an outlet for a second byproduct stream,
wherein the outlet for the second byproduct stream is in fluid communication with an inlet of a static crystallization unit having an outlet for a third product water stream and an outlet for a third byproduct stream,
wherein the third product water stream is in fluid communication with the first byproduct stream.

### Claim 7 (depends on 6)

The apparatus of claim 6, wherein, in use, the feed stream of saline solution in a first desalination step is passed through the reverse osmosis membrane desalination plant to form the first product water stream having a reduced salt concentration relative to that of the feed stream of saline solution and the first byproduct stream having an increased salt concentration relative to that of the feed stream of saline solution,
wherein, in use, the first byproduct stream is passed in a second desalination step through the first falling film crystallization unit to form the second product water stream having a reduced salt concentration relative to that of the first byproduct stream and the second byproduct stream having an increased salt concentration relative to that of the first byproduct stream.

### Claim 8 (depends on 6)

The apparatus of claim 6, wherein the reverse osmosis membrane desalination plant is an in-land desalination plant.

### Claim 9 (depends on 8)

The apparatus of claim 8, where the plant produces desalinated water, salt power, conditioned air, or any combination thereof.