WO2021152356A1 - Procédé et système de récupération d'eau et de sels à partir de rejet de saumure d'une installation de dessalement conduisant à un système de rejet zéro liquide - Google Patents

Procédé et système de récupération d'eau et de sels à partir de rejet de saumure d'une installation de dessalement conduisant à un système de rejet zéro liquide Download PDF

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Publication number
WO2021152356A1
WO2021152356A1 PCT/IB2020/052929 IB2020052929W WO2021152356A1 WO 2021152356 A1 WO2021152356 A1 WO 2021152356A1 IB 2020052929 W IB2020052929 W IB 2020052929W WO 2021152356 A1 WO2021152356 A1 WO 2021152356A1
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WIPO (PCT)
Prior art keywords
salts
stage concentrate
water
recovering
desalination plant
Prior art date
Application number
PCT/IB2020/052929
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English (en)
Inventor
Tapas Chatterjee
Original Assignee
Tapas Chatterjee
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tapas Chatterjee filed Critical Tapas Chatterjee
Publication of WO2021152356A1 publication Critical patent/WO2021152356A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/06—Flash distillation
    • B01D3/065—Multiple-effect flash distillation (more than two traps)
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C02F1/08—Thin film evaporation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C02F1/048—Purification of waste water by evaporation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F2001/5218—Crystallization
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
    • Y02A20/124—Water desalination

Definitions

  • the present invention relates to a process and a system for recovery of water and salts from desalination plant brine reject.
  • the present invention therefore leads to zero liquid discharge for desalination plant.
  • Desalination process refers to the removal of salts from saline water, such as brackish water and seawater, in order to obtain fresh water for domestic or industrial purposes.
  • desalination processes there are two classes of desalination processes, namely thermal-based and membrane-based processes.
  • the main thermal desalination processes for seawater desalination are multi-stage flash process, multi-effect distillation process, and vapour compression process.
  • the saline water is treated into two streams.
  • the first stream is fresh water containing a low concentration of salt while the second one is the brine with concentrated salt.
  • desalination occurs as a result of permeation of components through a selective permeable membrane.
  • Reverse osmosis (RO), nano -filtration (NF), forward osmosis (FO), and membrane distillation (MD), electro -dialysis (ED), electro-de-ionization (EDI), and microbial desalination cell (MDC) are some of the membrane -based desalination processes.
  • RO process is the most widely due to remarkable advances of this technology.
  • the advances lead to significant cost reduction of RO process.
  • Sorek desalination plant is an example of the largest SWRO plant which is located in Sorek, Israel, with a production capacity of 624,000 m 3 /day.
  • RO reverse osmosis
  • dissolved solutes including charged ion from water are separated via a semi-permeable membrane that allows passing water in preference to the solute.
  • the driving force is a pressure difference between the two membrane sides, i.e. feed side and permeate side.
  • a saline solution is pumped into RO unit and a pressure gradient is applied (pressure required to exceed the osmotic pressure of solution) the water migrates across the membrane toward the permeate side while the salts and other components are retained by the membrane on the feed side.
  • the overall result is two streams with different concentration of salt.
  • the first stream is brine with increased concentration in concentrate side while the other is depleted of salts in the permeate side.
  • membrane-based desalination processes discharges brine (hereinafter referred to as desalination plant brine reject) back into the environment.
  • the desalination plant brine reject contains a high concentration of salt and other pollutants.
  • the pollutant components in the desalination plant brine reject can be classified as corrosion products, anti-scaling additives, anti-fouling additives, halogenated organic compounds, anti-foaming additives, oxygen scavengers, acid, and concentrate.
  • the desalination plant brine reject brings negative impact on the environment due to its salt concentration and chemical content.
  • the environment where the desalination plant brine reject is being discharged experiences physicochemical impact due to salinity, temperature, etc. which tend to alter the physicochemical properties of receiving water and adversely effects on the marine life.
  • Other impacts of discharge of desalination plant brine reject are reported in literature.
  • Valuable recovered salt can be used to reduce the overall desalination cost. This option provides the possibility to obtain valuable components, both water and salts, that result in increased water recovery and reduced the overall water production cost. By doing so, a dual-purpose plant for desalination and salt production is achieved.
  • Geo-Processors USA, Inc. have reported an integrated process for desalination followed by extraction of dissolved solid from managing the desalination plant brine reject. Typically, the process involves one or more steps of reaction and evapo-cooling supplemented by conventional mineral and chemical processing steps.
  • Turek et al. have investigated some integrated processes that involve membrane (electro- dialysis, nano filtration, and reverse osmosis) based desalination process for producing potable water and subjecting the desalination plant brine reject to multi-stage flash process.
  • membrane electro- dialysis, nano filtration, and reverse osmosis
  • Another integrated process that has been investigated includes ultra filtration process (UF), which is followed by nano -filtration based process (NF), which is followed by multi-stage flash process (MSF) which is followed by crystallization process.
  • UF ultra filtration process
  • NF nano -filtration based process
  • MSF multi-stage flash process
  • UDF ultra filtration process
  • NF nano-filtration based process
  • RO reverse osmosis filtration
  • MSF multi-stage flash process
  • NF is used to remove bivalent ions from the feed stream.
  • the NF permeate with reduced salt is delivered to RO unit. Due to lower osmotic pressure as the result of NF softening step, RO can reach higher water recovery.
  • MD and MCr are introduced. MCr increases solute concentration of solution above its saturation limit in which crystal nucleate and growth.
  • the present invention provides a zero liquid discharge process for recovering potable water and different salts from desalination plant brine reject.
  • the process comprises subjecting the desalination plant brine reject to falling film evaporation process to produce water vapour and a first stage concentrate.
  • the process further comprises subjecting the first stage concentrate to evaporative crystallization process to produce water vapour, and a second stage concentrate.
  • the process further comprises subjecting the second stage concentrate to mechanical thickening process and to obtain a third stage concentrate and a purge.
  • the process further comprises recovering sodium chloride salt from the third stage concentrate.
  • the process further comprises recovering other elements or salts from the purge.
  • the process further comprises condensing the water vapour thus obtained to produce potable water.
  • a system for producing potable water and salts from desalination plant brine reject comprising a falling film evaporator receiving the desalination plant brine reject and producing therefrom water vapour and a first stage concentrate.
  • the system further comprises an evaporative crystallizer receiving the first stage concentrate from the falling film evaporator and producing therefrom water vapour and a second stage concentrate.
  • the system further comprises a mechanical thickening device receiving the second stage concentrate from the evaporative crystallizer and producing therefrom a third stage concentrate and a purge.
  • the system further comprises a first recovery device for recovering sodium chloride salt from the third stage concentrate.
  • the system further comprises at least one further recovery device for recovering other elements / salts from the purge.
  • the system further comprises at least one condensing unit for producing potable water by condensing water vapour as produced.
  • Figure 1 demonstrates a flow chart of the process for producing potable water and salts from desalination plant brine reject
  • Figure 2 demonstrates a block diagram of the system for producing potable water and salts from desalination plant brine reject
  • Figure 3 demonstrates a flow chart of the process for producing Bromine from Feed Bittern.
  • Figure 4 demonstrates a flow chart of the process for producing NaCl from Mother Liquor 2;
  • Figure 5 demonstrates a flow chart of the process for producing KC1 from Mother Liquor 3;
  • Figure 6 demonstrates a flow chart of the process for producing MgCh from Mother Liquor 4; and
  • Figure 7 demonstrates a flow chart of the process for producing KC1 from Slurry
  • the process (100) comprises subjecting the desalination plant brine reject to falling film evaporation process (102) to produce water vapour and a first stage concentrate.
  • the process further comprises subjecting the first stage concentrate to evaporative crystallization process (104) to produce water vapour, and a second stage concentrate.
  • the process further comprises subjecting the second stage concentrate to mechanical thickening process (106) and to obtain a third stage concentrate and a purge.
  • the process further comprises recovering sodium chloride salt (108) from the third stage concentrate.
  • the process further comprises recovering other elements / salts (110) from the purge.
  • the process further comprises condensing (112) the water vapour thus obtained to produce potable water.
  • recovering other elements / salts (110) from the purge comprises recovering Bromine from the purge.
  • a process (300) for recovering bromine from the purge is illustrated in Figure 3 and the same comprises acidification (302) of the purge.
  • the purge may be acidified using HC1, preferably about 30% of HC1.
  • the acidified purge is heated (304) to obtain Mother Fiquor - 1 (MF1).
  • Chlorine is added to Mother Fiquor - 1 (MF1) and the same is heated to obtain Bromine (preferably in the form of vapours) and Mother Fiquor - 2 (MF2).
  • the heating may be carried out for example, by using steam.
  • the addition of Chlorine to the Mother Fiquor - 1 (MF1) and heating with steam may be carried out in a stripping column.
  • the Brome may then be condensed and subjected to purification.
  • recovering other elements / salts (110) from the purge comprises recovering sodium chloride from Mother Fiquor - 2 (MF2).
  • a process (400) for recovering sodium chloride from Mother Fiquor - 2 (MF2) (or alternatively referred to as Bittern from Bromine Plant) is illustrated in Figure 4 and the same comprises subjecting the Bittern to forced circulation crystallization (401) to obtain slurry-1.
  • the Slurry - 1 may be subjected to a mechanical thickening process (402) to obtain Mother Fiquor 3 (MF3) and Purge -2.
  • the MF-3 is further subjected to centrifugation (403) to obtain sodium chloride.
  • recovering other elements / salts (110) from the purge comprises recovering Potassium chloride crystals (KC1) from Purge - 2.
  • a process (500) for recovering Potassium chloride crystals (KC1) from Purge - 2 is illustrated in Figure 5 and the same comprises subjecting the Purge - 2 to cooling crystallization (502) to obtain Mother Liquor 4 (ML4).
  • the Mother Liquor 4 (ML4) may be subjected to a mechanical thickening process (503) to obtain Mother Liquor 5 (ML5) and Purge -3.
  • Mother Liquor 5 may be subjected to centrifugation (504) to obtain a sediment.
  • the sediment is then subjected to leaching (505) in a leaching tank using a leachant, which may be water.
  • a leachant which may be water.
  • the water may be at 5°C.
  • the leachant obtained from the leaching process may be subjected to mechanical thickening process (506) to obtain Mother Liquor 6 (ML6) which may be centrifuged (507) to obtain Potassium chloride crystals (KC1) and a liquid portion containing MgSCL. It is possible to recover MgSCL from the liquid containing the MgSCL.
  • Any liquid obtained during centrifugation of the Mother Liquor 5 may be mixed with Purge 2 or with Mother Liquor 4 (ML4).
  • Any liquid obtained during centrifugation of Mother Liquor 6 (ML6) may be similarly brought back to any previous stage in the process (500).
  • Any purge obtained from the mechanical thickening process (506) may be mixed with Purge 3.
  • recovering other elements / salts (110) from the purge comprises recovering Magnesium Chloride (MgC12) from Purge - 3.
  • a process (600) for recovering Magnesium Chloride (MgC12) from Purge - 3 is illustrated in Figure 6 and the same comprises subjecting Purge - 3 to flash evaporation (602) to separate potable water and brine. The brine obtained is subjected to cooling crystallization (603) to obtain slurry-3. Slurry 3 is subjected to mechanical thickening to obtain slurry-4, which may be centrifuged (605) to obtain Magnesium Chloride crystals (606).
  • the desalination plant brine reject is fed to a multi-stage falling film evaporation process.
  • the falling film evaporation process is a multi-effect falling film evaporation process.
  • recovering sodium chloride salt from the third stage concentrate comprises centrifuging the third stage concentrate.
  • the sodium chloride salt thus recovered is subjected to drying.
  • recovering other elements / salts from the purge comprises separating the different elements / salts on the basis of their solubility.
  • the other salts thus recovered are subjected to drying.
  • the other elements / salts include bromine, magnesium sulphate, magnesium bromate, and potassium chloride.
  • the system (200) comprises a falling film evaporator (202) receiving the desalination plant brine reject and producing therefrom water vapour and a first stage concentrate.
  • the system (200) further comprises an evaporative crystallizer (204) receiving the first stage concentrate from the falling film evaporator (202) and producing therefrom water vapour and a second stage concentrate.
  • the system (200) further comprises a mechanical thickening device (206) receiving the second stage concentrate from the evaporative crystallizer (204) and producing therefrom a third stage concentrate and a purge.
  • the system (200) further comprises a first recovery device (208) for recovering sodium chloride salt from the third stage concentrate.
  • the system (200) further comprises a second recovery device (210) for recovering salts of other ions from the purge.
  • the system (200) further comprises at least one condensing unit (212) for producing potable water by condensing water vapour as produced.
  • the first recovery device (208) for recovering sodium chloride salt from the third stage concentrate is a centrifuge device.
  • the second recovery device (210) for recovering salts of other ions from the purge is a centrifuge device.
  • the system (200) further comprises a first drier (214) for drying the sodium chloride salt thus recovered in the first recovery device (208).
  • the system (200) further comprises a second drier (216) for drying the salts of other ions thus recovered in the second recovery device (210). It is not only important to recover maximum quantity of water from the desalination plant brine reject but the quality of water thus recovered is also important. In an embodiment of the invention, more than 85%, preferably more than 90% and most preferably more than 92.5% of water is recovered from the desalination plant brine reject. In an embodiment of the invention, the water thus recovered is of potable quality.
  • the desalination plant with the capacity of one million litre /day was operated for the production of water, salt, and other value added products. 17,00,000L Sea water having 3% Sodium chloride (NaCl) concentration is fed to plant every day.
  • Reverse osmosis Power - 3.0 KwH/KL
  • the reverse osmosis generates potable fresh water of 700,000 L/day.
  • the reject (brine) generated through the process of reverse osmosis is 1,000,000 L/day or 1050,000 kg/day with a concentration 6% NaCl (S.G- 1.05).
  • the output brine generated by the reverse osmosis process is then subjected to evaporation in a 7 effect Falling Film Evaporator. Up to 25% of the brine is evaporated generating a first stage concentrate @ 262,500 kg/day. The water recovered from the brine in the 7 effect Falling Film Evaporator is 787,500 kg/day.
  • the First stage concentrate is subjected to Evaporative Crystallization to generate a second stage concentrate and potable water.
  • the potable water recovered during the Evaporative Crystallization is 189,000 kg/day.
  • the amount of second stage concentrate recovered during Evaporative Crystallization is 73,500 kg/day.
  • the second stage concentrate is subjected to mechanical thickening to obtain 7875 kg/day of Purge and 65625 kg/day of third stage concentrate.
  • the third stage concentrate contained 96% NaCl salt. From the third stage concentrate NaCl salt having about 0.2 % moisture was recovered. In particular, 63000 kg/day of NaCl was recovered from the third stage concentrate.
  • the 7875 kg/day of Purge was processed to yield NaCl (1514 kg/day) and other value added products which included MgCF (676 kg/day), MgSCU (433 kg/day), KC1 (150 kg/day) and Bromine (13.7 kg/day).
  • MgCF 676 kg/day
  • MgSCU 433 kg/day
  • KC1 150 kg/day
  • Bromine 13.7 kg/day

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Heat Treatment Of Water, Waste Water Or Sewage (AREA)

Abstract

L'invention concerne un procédé et un système de récupération d'eau et de sels à partir d'un rejet de saumure d'une installation de dessalement. L'eau ainsi produite est de qualité potable. Les sels produisent ainsi un sel de chlorure de sodium de pureté élevée. Outre le sel de chlorure de sodium, d'autres sels/éléments tels que le chlorure de magnésium, le sulfate de magnésium, le chlorure de potassium et le brome sont récupérés séparément. Le processus et le système conduisent à une usine de dessalement à rejet zéro liquide.
PCT/IB2020/052929 2020-01-30 2020-03-27 Procédé et système de récupération d'eau et de sels à partir de rejet de saumure d'une installation de dessalement conduisant à un système de rejet zéro liquide WO2021152356A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IN202011004232 2020-01-30
IN202011004232 2020-01-30

Publications (1)

Publication Number Publication Date
WO2021152356A1 true WO2021152356A1 (fr) 2021-08-05

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PCT/IB2020/052929 WO2021152356A1 (fr) 2020-01-30 2020-03-27 Procédé et système de récupération d'eau et de sels à partir de rejet de saumure d'une installation de dessalement conduisant à un système de rejet zéro liquide

Country Status (1)

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WO (1) WO2021152356A1 (fr)

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CHARISIADIS CHRISTOS: "Brine Zero Liquid Discharge (ZLD) Fundamentals and Design. A guide to the basic conceptualization of the ZLD/MLD process design and the relative technologies involved", LENNTECH B V, September 2018 (2018-09-01), pages 36 - 37, XP055845286, DOI: 10.13140/RG.2.2.19645.31205 *
HASSAN REDA: "Using ZLD technique for safe and economic disposal of desalination plant brines in Egypt", J. EGYPT . ACAD. SOC. ENVIRON. DEVELOP., vol. 15, no. 2, 2014, pages 67 - 81, XP055845279 *

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