WO2008085106A1 - Method for purifying water by means of an ro device - Google Patents

Method for purifying water by means of an ro device Download PDF

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Publication number
WO2008085106A1
WO2008085106A1 PCT/SE2007/051046 SE2007051046W WO2008085106A1 WO 2008085106 A1 WO2008085106 A1 WO 2008085106A1 SE 2007051046 W SE2007051046 W SE 2007051046W WO 2008085106 A1 WO2008085106 A1 WO 2008085106A1
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WO
WIPO (PCT)
Prior art keywords
caused
water
concentrate
arrangement
equipment
Prior art date
Application number
PCT/SE2007/051046
Other languages
French (fr)
Inventor
Aapo SÄÄSK
Original Assignee
Scarab Development Ab
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Filing date
Publication date
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Publication of WO2008085106A1 publication Critical patent/WO2008085106A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/58—Multistep processes
    • 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
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/447—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by membrane distillation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/36—Pervaporation; Membrane distillation; Liquid permeation
    • B01D61/364—Membrane distillation
    • B01D61/3641—Membrane distillation comprising multiple membrane distillation steps
    • 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
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/04—Specific process operations in the feed stream; Feed pretreatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/08—Specific process operations in the concentrate stream
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2317/00—Membrane module arrangements within a plant or an apparatus
    • B01D2317/02—Elements in series
    • B01D2317/022—Reject series
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2317/00—Membrane module arrangements within a plant or an apparatus
    • B01D2317/08—Use of membrane modules of different kinds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/025—Reverse osmosis; Hyperfiltration
    • 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
    • C02F1/14—Treatment of water, waste water, or sewage by heating by distillation or evaporation using solar energy
    • 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
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/30—Wastewater or sewage treatment systems using renewable energies
    • Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy

Definitions

  • the present invention relates to a method for cleaning water by means of RO equipment.
  • RO reverse osmosis
  • RO equipment provides up to 40% permeate and 60% concentrate, i.e. a water residual of the unclean water. More advanced RO equipment can give up to 60% permeate and 40% concentrate.
  • RO equipment One problem with RO equipment is that there remains a large fraction of concentrate when the cleaning of the water has been completed, and for this reason the RO equipment in itself is not as efficient as is desired.
  • the present invention solves this problem.
  • the present invention thus relates to a method for cleaning water by means of RO equipment where the unclean water is subject to pre-treatment , and it is characterised in that the pre-treated water is caused to be led through a membrane distillation arrangement on its cold side before the RO equipment, in that concentrate from the RO equipment is caused to be heated, and in that the heated concentrate is caused to be led through the membrane distillation arrangement on its hot side.
  • FIG. 1 shows schematically a method comprising an MD arrangement and RO equipment in a system, to which system a heater and a heat exchanger have been connected;
  • FIG. 2 shows schematically a method comprising an MD arrangement and RO equipment in a system, to which system a heat exchanger has been connected;
  • FIG. 3 shows schematically a method comprising an MD arrangement and RO equipment in a system, to which system steam is caused to be supplied;
  • FIG. 4 shows schematically a method comprising an MD arrangement and RO equipment in a system, to which system steam is caused to be supplied to unclean water in order for heating of the water to take place.
  • the present invention thus relates to a method for cleaning water by means of RO equipment 2 where the unclean water 10 is subject to pre-treatment .
  • the unclean water 10 may be pre-treated in some known manner, for example, by ultrafiltration, nanofiltration or microfiltration, or with active charcoal .
  • Membrane distillation has been known for cleaning water since the 1980s.
  • This is an arrangement for allowing a first liquid to pass close to a second liquid, while not mixing with it, which arrangement comprises a number of flat sheets.
  • a first sheet is provided with a membrane through which water can pass only when it is in the gaseous phase. Temperature differences between sheets cause the water to vaporise, to pass through the membrane and to condense onto a second wall, which is colder than the water that is to be cleaned. The surface tension of the water ensures that the water cannot pass through the membrane.
  • the term "water passes through the membrane” is used to denote that the water is in its vapour phase.
  • MD can be used in many fields. Seawater, for example, can be allowed to flow along the membrane, and vaporised water to pass through the membrane to be collected on the other side of the membrane in order to be used as clean water. In this way, all substances, except for pure water, remain in the water that is to be cleaned, denoted hereunder as a "water residual".
  • water residual There are several areas of application for membrane distillation. It may conceivably be waste water that is to be cleaned, not only to clean the water in order to use clean water in industries that require clean water, but also to clean the water such that an essentially solid byproduct of undesired substances remains.
  • Figures 1-3 show, according to the invention, that pre- treated unclean water 13 is caused to be led through a membrane distillation arrangement 1 on its cold side before the RO equipment 2, in that concentrate 16 from the RO equipment is caused to be heated, and in that the heated concentrate 16 is caused to be led through the membrane distillation arrangement 1 on its hot side.
  • the pre-treated unclean water 13 is caused to be led through the MD arrangement 1, the water 13 circulates as cooling water, and it is heated in this way to a relatively low temperature, approximately 20- 40 0 C, or to as high a temperature that the RO membrane can withstand, while remaining under 100 0 C.
  • the pre-treated heated unclean water 14 is subsequently caused to be led into the RO equipment 2, which is caused to remove a major part of the dissolved salts.
  • the heating that is caused to take place on the cold side of the membrane distillation arrangement 1 ensures that the yield of permeate 15 from the RO equipment 2 increases.
  • the increase in the production of permeate 15 is related in a linear manner to the increase in temperature.
  • the temperature of the unclean water 10 is approximately 10-40 0 C.
  • the pre- treated unclean water 13 is caused to be heated at the cold side of the MD arrangement 1 by a number of degrees, to approximately 20-40 0 C, or to as high a temperature as the RO membrane can withstand, while remaining under 100 0 C.
  • the RO equipment 2 is caused to separate the water 14 into a permeate 15, which is clean water, and a concentrate 16.
  • the permeate 15 is caused to be collected as clean water 3 without contaminants and it can thus be used as clean water for the intended purpose.
  • the permeate 15 is caused to pass a further MD arrangement 17, whereby a higher degree of purity is caused to be obtained than that obtained with water treated by RO.
  • the concentrate 16 from the RO equipment 2 is caused to be heated in a heat exchanger 6, see Figures 1 and 2.
  • a heater 9 is caused to heat the water in the heat exchanger 6, see Figure 1.
  • the heater 9 is a solar collector. According to a further preferred embodiment, the heater 9 is an electrical cartridge. The heater 9 may also be, for example, a further heat exchanger or a burner, such that the heater 9 is to be caused to lead heated liquid through the heat exchanger 6.
  • the heated water after the heat exchanger 6 is caused to circulate through the membrane distillation arrangement 1, whereby a further fraction of water in the form of vapour formed from concentrate 16 passes the membrane in the mem- brane distillation arrangement 1 as clean water 3 without contaminants. There will, however, remain a water residual 4 after the membrane distillation process 1.
  • the water residual 4 from the membrane distillation process 1 is caused to be boiled in a boiler arrangement 20.
  • the boiler arrangement 20 may be of various known types, for example, falling film evaporators, crystallisers, spray dryers or steam compressors.
  • Figure 2 shows, according to a further embodiment, how steam 8 from the boiler arrangement 20 is caused to be led to the heat exchanger 6 in order to heat the concentrate 16 from the RO equipment 2.
  • the condensed steam 7, which is steam 8 that has passed the heat exchanger 6, is caused to be led to clean water 3 without contaminants.
  • Figure 3 shows, according to a further embodiment, how steam 8 is caused to be led into the concentrate 16, whereby the water in the system is caused to circulate.
  • a mixture of steam 8 and concentrate 16, which is water in its liquid form, has in this case obtained a density that is lower than that of concentrate 16 alone. Furthermore, at least a part of the system is extended in the vertical direction.
  • vertical means that an angle to a plumbline may be present.
  • the purpose of the said mixture is to achieve circulation in that the mixture with lower density rises in a first vertical part of the system.
  • the steam 8 condenses as the circulation proceeds and is converted to water in its liquid form again.
  • the density falls gradually as the steam 8 condenses.
  • the circulatory water accompanies the flow in the system and falls in a second vertical part of the system. A circulation is in this way obtained in a system that thus does not require a pump to pump the water in the system around.
  • the concentrate 16 is heated by the steam 8, and for this reason no further heating of the concentrate 16 is required.
  • FIG. 4 shows, according to a further preferred embodiment, that steam 8a, 8b, 8c is caused to be led into the water 10, 13, 14, whereby the water 10, 13, 14 in the system is caused to circulate.
  • permeate 15, 18, 19 and steam 8d are caused to be led to different containers, whereby water with different degrees of purity is obtained from the system, for example, clean water 3a without contaminants from the permeate 15 from the RO equipment.
  • the permeate 15 is caused to pass a second MD arrangement 17, whereby a permeate 18 that is purer than the permeate 15 from the RO equipment 2 is caused to be obtained.
  • the permeate 18 is caused to be collected as clean water 3b without contaminants.
  • the permeate 19 from the MD arrangement 1 is caused to be carried to clean water 3c without contaminants in order to separate the permeate 19 from the permeate 15.
  • Steam 8d from the boiler arrangement 20 is caused to condense and is collected as clean water 3d without contaminants. At least one of the permeate 15, 18 19 and steam 8d is caused to be led to separate containers.
  • the membrane distillation is of the type of membrane distillation that has an air gap, known as "air gap membrane distillation (AGMD)".
  • AGMD air gap membrane distillation
  • the membrane distillation arrangement 1, the RO equipment 2, the boiler arrangement 20 and the heat exchanger 6 may be designed in another suitable manner with- out deviating from the fundamental concept of the invention

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

Abstract

The present invention relates to a method for cleaning water by means of RO equipment (2) where unclean water (10) is pre-treated. The invention is characterised in that the pre-treated unclean water (13) is caused to be led through a membrane distillation arrangement (1) on its cold side before the RO equipment (2), in that the concentrate (16) from the RO equipment (2) is caused to be heated, and in that the heated concentrate (16) is caused to be led through the membrane distillation arrangement (1) on its hot side.

Description

Method for purifying water by means of an RO device
The present invention relates to a method for cleaning water by means of RO equipment.
It is necessary to clean water for a number of purposes. It may be a question of cleaning water for household use, desalting seawater for a purpose, cleaning water for use within several industrial fields, or concentrating undesired substances, i.e. a byproduct, to as small a volume as possible, or indeed to a solid material.
One way is to use a method comprising reverse osmosis, abbreviated as "RO". It is in this case required that the water that is to pass a semipermeable membrane in order to separate the water from, for example salts and ions, is placed under pressure in order for the reverse osmosis process to arise.
RO equipment provides up to 40% permeate and 60% concentrate, i.e. a water residual of the unclean water. More advanced RO equipment can give up to 60% permeate and 40% concentrate.
One problem with RO equipment is that there remains a large fraction of concentrate when the cleaning of the water has been completed, and for this reason the RO equipment in itself is not as efficient as is desired.
The present invention solves this problem.
The present invention thus relates to a method for cleaning water by means of RO equipment where the unclean water is subject to pre-treatment , and it is characterised in that the pre-treated water is caused to be led through a membrane distillation arrangement on its cold side before the RO equipment, in that concentrate from the RO equipment is caused to be heated, and in that the heated concentrate is caused to be led through the membrane distillation arrangement on its hot side.
The invention is described in more detail below, partially in association with embodiments of the invention shown in the attached drawings, where
- Figure 1 shows schematically a method comprising an MD arrangement and RO equipment in a system, to which system a heater and a heat exchanger have been connected;
- Figure 2 shows schematically a method comprising an MD arrangement and RO equipment in a system, to which system a heat exchanger has been connected;
- Figure 3 shows schematically a method comprising an MD arrangement and RO equipment in a system, to which system steam is caused to be supplied;
- Figure 4 shows schematically a method comprising an MD arrangement and RO equipment in a system, to which system steam is caused to be supplied to unclean water in order for heating of the water to take place.
The present invention thus relates to a method for cleaning water by means of RO equipment 2 where the unclean water 10 is subject to pre-treatment . The unclean water 10 may be pre- treated in some known manner, for example, by ultrafiltration, nanofiltration or microfiltration, or with active charcoal .
Membrane distillation, abbreviated "MD", has been known for cleaning water since the 1980s. This is an arrangement for allowing a first liquid to pass close to a second liquid, while not mixing with it, which arrangement comprises a number of flat sheets. A first sheet is provided with a membrane through which water can pass only when it is in the gaseous phase. Temperature differences between sheets cause the water to vaporise, to pass through the membrane and to condense onto a second wall, which is colder than the water that is to be cleaned. The surface tension of the water ensures that the water cannot pass through the membrane. The term "water passes through the membrane" is used to denote that the water is in its vapour phase.
MD can be used in many fields. Seawater, for example, can be allowed to flow along the membrane, and vaporised water to pass through the membrane to be collected on the other side of the membrane in order to be used as clean water. In this way, all substances, except for pure water, remain in the water that is to be cleaned, denoted hereunder as a "water residual". There are several areas of application for membrane distillation. It may conceivably be waste water that is to be cleaned, not only to clean the water in order to use clean water in industries that require clean water, but also to clean the water such that an essentially solid byproduct of undesired substances remains.
Figures 1-3 show, according to the invention, that pre- treated unclean water 13 is caused to be led through a membrane distillation arrangement 1 on its cold side before the RO equipment 2, in that concentrate 16 from the RO equipment is caused to be heated, and in that the heated concentrate 16 is caused to be led through the membrane distillation arrangement 1 on its hot side. When the pre-treated unclean water 13 is caused to be led through the MD arrangement 1, the water 13 circulates as cooling water, and it is heated in this way to a relatively low temperature, approximately 20- 40 0C, or to as high a temperature that the RO membrane can withstand, while remaining under 100 0C. The pre-treated heated unclean water 14 is subsequently caused to be led into the RO equipment 2, which is caused to remove a major part of the dissolved salts.
The heating that is caused to take place on the cold side of the membrane distillation arrangement 1 ensures that the yield of permeate 15 from the RO equipment 2 increases. The increase in the production of permeate 15 is related in a linear manner to the increase in temperature. The temperature of the unclean water 10 is approximately 10-40 0C. The pre- treated unclean water 13 is caused to be heated at the cold side of the MD arrangement 1 by a number of degrees, to approximately 20-40 0C, or to as high a temperature as the RO membrane can withstand, while remaining under 100 0C.
The RO equipment 2 is caused to separate the water 14 into a permeate 15, which is clean water, and a concentrate 16. The permeate 15 is caused to be collected as clean water 3 without contaminants and it can thus be used as clean water for the intended purpose.
According to a further preferred embodiment, the permeate 15 is caused to pass a further MD arrangement 17, whereby a higher degree of purity is caused to be obtained than that obtained with water treated by RO.
According to a preferred embodiment, the concentrate 16 from the RO equipment 2 is caused to be heated in a heat exchanger 6, see Figures 1 and 2.
According to a preferred embodiment, a heater 9 is caused to heat the water in the heat exchanger 6, see Figure 1.
According to a preferred embodiment, the heater 9 is a solar collector. According to a further preferred embodiment, the heater 9 is an electrical cartridge. The heater 9 may also be, for example, a further heat exchanger or a burner, such that the heater 9 is to be caused to lead heated liquid through the heat exchanger 6.
The heated water after the heat exchanger 6 is caused to circulate through the membrane distillation arrangement 1, whereby a further fraction of water in the form of vapour formed from concentrate 16 passes the membrane in the mem- brane distillation arrangement 1 as clean water 3 without contaminants. There will, however, remain a water residual 4 after the membrane distillation process 1.
According to a further embodiment, the water residual 4 from the membrane distillation process 1 is caused to be boiled in a boiler arrangement 20. The boiler arrangement 20 may be of various known types, for example, falling film evaporators, crystallisers, spray dryers or steam compressors.
Figure 2 shows, according to a further embodiment, how steam 8 from the boiler arrangement 20 is caused to be led to the heat exchanger 6 in order to heat the concentrate 16 from the RO equipment 2. The condensed steam 7, which is steam 8 that has passed the heat exchanger 6, is caused to be led to clean water 3 without contaminants.
Figure 3 shows, according to a further embodiment, how steam 8 is caused to be led into the concentrate 16, whereby the water in the system is caused to circulate. A mixture of steam 8 and concentrate 16, which is water in its liquid form, has in this case obtained a density that is lower than that of concentrate 16 alone. Furthermore, at least a part of the system is extended in the vertical direction. The term
"vertical" means that an angle to a plumbline may be present. The purpose of the said mixture is to achieve circulation in that the mixture with lower density rises in a first vertical part of the system. The steam 8 condenses as the circulation proceeds and is converted to water in its liquid form again. The density falls gradually as the steam 8 condenses. The circulatory water accompanies the flow in the system and falls in a second vertical part of the system. A circulation is in this way obtained in a system that thus does not require a pump to pump the water in the system around.
Furthermore, the concentrate 16 is heated by the steam 8, and for this reason no further heating of the concentrate 16 is required.
Figure 4 shows, according to a further preferred embodiment, that steam 8a, 8b, 8c is caused to be led into the water 10, 13, 14, whereby the water 10, 13, 14 in the system is caused to circulate.
According to a further embodiment according to Figure 4, permeate 15, 18, 19 and steam 8d are caused to be led to different containers, whereby water with different degrees of purity is obtained from the system, for example, clean water 3a without contaminants from the permeate 15 from the RO equipment. The permeate 15 is caused to pass a second MD arrangement 17, whereby a permeate 18 that is purer than the permeate 15 from the RO equipment 2 is caused to be obtained. The permeate 18 is caused to be collected as clean water 3b without contaminants. Furthermore, the permeate 19 from the MD arrangement 1 is caused to be carried to clean water 3c without contaminants in order to separate the permeate 19 from the permeate 15. Steam 8d from the boiler arrangement 20 is caused to condense and is collected as clean water 3d without contaminants. At least one of the permeate 15, 18 19 and steam 8d is caused to be led to separate containers.
According to a further preferred embodiment, the membrane distillation is of the type of membrane distillation that has an air gap, known as "air gap membrane distillation (AGMD)".
A number of embodiment procedures and uses have been described above. However, the membrane distillation arrangement 1, the RO equipment 2, the boiler arrangement 20 and the heat exchanger 6 may be designed in another suitable manner with- out deviating from the fundamental concept of the invention
The present invention is thus not limited to the embodiment procedures described above, since it can be varied within the scope defined by the attached patent claims.

Claims

Claims
1. A method for cleaning water by means of RO equipment (2) where unclean water (10) is pre-treated, c h a r a c t e r is e d in that the pre-treated unclean water (13) is caused
5 to be led through a membrane distillation arrangement (1) on its cold side before the RO equipment (2), in that concentrate (16) from the RO equipment (2) is caused to be heated, and in that the heated concentrate (16) is caused to be led through the membrane distillation arrangement (1) on its hot
W side.
2. A method according to claim 1, characte ri sed in that the permeate (15) is caused to pass a further MD arrangement (17), whereby a higher degree of purity is caused to be obtained than that obtained with water that has been
15 treated by RO.
3. A method according to either claim 1 or 2, charac¬ teri sed in that the concentrate (16) from the RO equip¬ ment (2) is caused to be heated in a heat exchanger (6) .
4. A method according to claim 3, characteri sed in 0 that a heater (9) is caused to heat the concentrate (16) in the heat exchanger (6) .
5. A method according to claim 4, characteri sed in that the heater (9) is a solar collector.
6. A method according to claim 4, characteri sed in5 that the heater (9) is an electrical cartridge.
7. A method according to any one of claims 1-6, character i sed in that a water residual (4) from the membrane distillation (1) is caused to be boiled in a boiler arrangement (20), in which way steam (8) is formed.
8. A method according to claim 7, characterised in that steam (8) from the boiler arrangement (20) is caused to be led to the heat exchanger (6) in order to heat the concentrate (16) from the RO equipment (2) .
5 9 . A method according to cla im 7 , c h a r a c t e r i s e d in that steam (8) is caused to be led into the concentrate (16), whereby the concentrate (16) is caused to circulate.
10. A method according to claim 7, characterised in that steam (8a, 8b, 8c) is caused to be led into the water
W (10, 13, 14), whereby the water (10, 13, 14) is caused to circulate .
11. A method according to any one of claims 1-10, characterised in that the permeate (15) is caused to pass a second MD arrangement (17), whereby a permeate (18) is caused
15 to be obtained that is more pure than the permeate (15) .
12. A method according to any one of claims 1-11, characterised in that at least one of permeate (15, 18, 19) and steam (8d) is caused to be led to separate containers.
13. A method according to any one of the preceding claims, 0 characterised in that the membrane distillation is of the type of membrane distillation with an air gap, known as "air gap membrane distillation. "
PCT/SE2007/051046 2007-01-12 2007-12-19 Method for purifying water by means of an ro device WO2008085106A1 (en)

Applications Claiming Priority (2)

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SE0700058-1 2007-01-12
SE0700058A SE530859C2 (en) 2007-01-12 2007-01-12 Method of purifying water by reverse osmosis

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102295377A (en) * 2010-06-28 2011-12-28 中国石油化工股份有限公司 Advanced treatment and reuse method of wastewater in olefin polymerization catalyst production
CN103663835A (en) * 2013-12-17 2014-03-26 中国电力工程顾问集团公司 Hybrid MSF (multistage flash)/RO (reverse osmosis) sea water desalination system
CN103762004A (en) * 2014-01-22 2014-04-30 清华大学 Method and system for concentrating radioactive waste water
CN103771640A (en) * 2012-10-19 2014-05-07 中国石油化工股份有限公司 Advanced treatment and reuse method of high-temperature nitrochlorobenzene wastewater

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Publication number Priority date Publication date Assignee Title
JPS63137705A (en) * 1986-12-01 1988-06-09 Hitachi Ltd Membrane distillation device
JPH04290597A (en) * 1991-03-19 1992-10-15 Hitachi Ltd Water treating equipment
JP2006320798A (en) * 2005-05-17 2006-11-30 Kochi Univ Method of producing highly concentrated brine and condensing system of seawater

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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CN102295377A (en) * 2010-06-28 2011-12-28 中国石油化工股份有限公司 Advanced treatment and reuse method of wastewater in olefin polymerization catalyst production
CN102295377B (en) * 2010-06-28 2013-08-14 中国石油化工股份有限公司 Advanced treatment and reuse method of wastewater in olefin polymerization catalyst production
CN103771640A (en) * 2012-10-19 2014-05-07 中国石油化工股份有限公司 Advanced treatment and reuse method of high-temperature nitrochlorobenzene wastewater
CN103771640B (en) * 2012-10-19 2015-11-25 中国石油化工股份有限公司 A kind of advanced treatment of nitro-chlorobenzene hot wastewater and reuse method
CN103663835A (en) * 2013-12-17 2014-03-26 中国电力工程顾问集团公司 Hybrid MSF (multistage flash)/RO (reverse osmosis) sea water desalination system
CN103762004A (en) * 2014-01-22 2014-04-30 清华大学 Method and system for concentrating radioactive waste water

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