CN116033959A - Membrane distillation device and method for operating the same - Google Patents
Membrane distillation device and method for operating the same Download PDFInfo
- Publication number
- CN116033959A CN116033959A CN202180056848.4A CN202180056848A CN116033959A CN 116033959 A CN116033959 A CN 116033959A CN 202180056848 A CN202180056848 A CN 202180056848A CN 116033959 A CN116033959 A CN 116033959A
- Authority
- CN
- China
- Prior art keywords
- secondary side
- pipe
- membrane
- pressure
- water supply
- Prior art date
- Legal status (The legal status 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 status listed.)
- Pending
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 57
- 238000004821 distillation Methods 0.000 title claims description 24
- 238000000034 method Methods 0.000 title claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 45
- 239000007788 liquid Substances 0.000 claims abstract description 18
- 238000004891 communication Methods 0.000 claims description 8
- 230000002209 hydrophobic effect Effects 0.000 claims description 6
- 239000012510 hollow fiber Substances 0.000 abstract description 27
- 239000000463 material Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 238000004382 potting Methods 0.000 description 5
- 238000009835 boiling Methods 0.000 description 4
- -1 polyethylene Polymers 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 239000004695 Polyether sulfone Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229920002492 poly(sulfone) Polymers 0.000 description 1
- 229920006393 polyether sulfone Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 235000002639 sodium chloride Nutrition 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Images
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
- B01D61/36—Pervaporation; Membrane distillation; Liquid permeation
- B01D61/362—Pervaporation
Landscapes
- Engineering & Computer Science (AREA)
- Water Supply & Treatment (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The liquid to be treated in the water tank (1) is supplied to the hollow fibers (11) of the membrane module (10) by a water supply pump (2), a pipe (3), a heat exchanger (4), and a pipe (5), and returned to the water tank (1). The secondary side (17) is depressurized by a depressurizing device (25). The water in the liquid to be treated flowing through the hollow fiber (11) evaporates, and is sucked and discharged from the secondary side (17) to the pipe (20). The gas phase part (1 a) of the water supply tank is communicated with the secondary side (17) through a pipe (7) and a valve (8), and the pressure difference P between the two parts 1 ‑P 2 20 to 90kPa.
Description
Technical Field
The invention relates to a membrane distillation device and an operation method thereof.
Background
The membrane distillation apparatus is configured to concentrate the liquid to be treated by supplying the liquid to be treated, which has been heated, to the primary side of the hydrophobic flat membrane or the hydrophobic hollow fiber membrane so that the vapor pressure on the secondary side of the membrane is equal to or lower than the vapor pressure on the primary side, thereby recovering only vapor from the liquid to be treated. Unlike a general distillation apparatus, a membrane distillation apparatus increases an evaporation surface area by using a membrane, and has an advantage of miniaturization of the apparatus.
An example of a conventional membrane distillation apparatus is shown in fig. 2. The liquid to be treated stored in the water feed tank 1 is sent to a heat exchanger (warmer) 4 via a pipe 3 having a water feed pump 2, is warmed by heat exchange with a high-temperature fluid, and is then sent to the membrane module 10 via a pipe 5.
In this conventional example, the membrane module 10 is a hollow fiber membrane module. In the membrane module 10, a plurality of hollow fibers 11 are carded and aligned into a hollow fiber bundle, which is arranged in the up-down direction. The hollow fiber bundles are bound at the upper and lower ends by potting materials 12 and 13.
The hollow fiber bundle is disposed in the housing 14 of the membrane module 10, and an inflow chamber 15 is formed above the upper potting material 12, and an outflow chamber 16 is formed below the lower potting material 13. The hollow fibers 11 communicate with the inflow chamber 15 and the outflow chamber 16, respectively.
The liquid to be treated from the pipe 5 flows into each hollow fiber 11 (primary side) from the inflow chamber 15, flows through the hollow fiber 11 to the outflow chamber 16, and returns from the outflow chamber 16 to the water tank 1 through the pipe 6.
Outside the hollow fibers 11 within the housing 14 and between the potting materials 12, 13 is a secondary side 17.
The secondary side 17 communicates with a pressure reducing device 25 via a pipe (vapor pipe) 20, a heat exchanger (cooler) 21, a pipe 22, a condensate tank 23, and a pipe 24, and the pressure reducing device 25 reduces the pressure of the secondary side 17.
When the liquid to be treated flows through the hollow fibers 17 (primary side), water in the liquid to be treated permeates the hollow fibers 11, becomes vapor, is sucked from the secondary side 17 and discharged to the pipe 20, and is cooled by the heat exchanger 21 to generate condensed water. The condensed water is stored in the condensed water tank 23.
In this conventional example, the secondary side 17 in the housing 14 communicates with the upper portion (gas phase portion 1 a) in the water supply tank 1 through the pipe 7.
Pressure sensors P1, P2, P3 are provided to detect the pressure in the gas phase portion 1a of the water supply tank 1, the piping 20, and the piping 5.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. Hei 3-52627.
In the membrane distillation apparatus, the negative pressure of the pressure reducing device 25 is transmitted from the secondary side 17 to the inside of the feed water tank 1 via the pipe 7. Therefore, the pressure in the pipe 3 on the intake side of the feed pump 2 is reduced, and cavitation may occur. In order to prevent this cavitation, it is necessary to increase the water head (water surface height) H in the water feed tank 1, and to increase the height of the water feed tank 1.
Disclosure of Invention
Problems to be solved by the invention
The invention aims to provide a membrane distillation device capable of preventing cavitation of a water feed pump without increasing the height of the water feed tank and an operation method thereof.
Means for solving the problems
The membrane distillation apparatus of the present invention is characterized by comprising: a membrane module, wherein the inside of the housing is divided into a primary side and a secondary side by a hydrophobic membrane; a liquid circulation supply mechanism having a water supply tank and a water supply pump for circulating and supplying the liquid to be treated to the primary side of the membrane module; a pressure reducing device configured to reduce pressure on a secondary side of the membrane module; and a communication mechanism for communicating the secondary side of the membrane module with the gas phase part of the water supply tank, wherein the pressure difference between the gas phase part of the water supply tank and the secondary side of the membrane module is 20-90 kPa.
In one aspect of the present invention, the communication portion has a pressure difference adjusting mechanism that adjusts the pressure difference.
In one aspect of the present invention, the communication portion having the pressure difference adjusting mechanism is a pipe having a valve.
In one aspect of the present invention, the communication portion is a pipe, an inner diameter of the pipe is 1/4 or less of an inner diameter of a steam pipe, and the steam pipe is connected to the secondary side so as to depressurize the secondary side and suck and discharge steam.
The method of operating a membrane distillation apparatus according to the present invention is characterized in that the opening degree of the valve is adjusted so that the pressure difference is 20 to 90kPa.
Effects of the invention
According to the present invention, by adjusting the pressure difference between the secondary side and the gas phase portion in the water supply tank to 20 to 90kPa, the pressure on the suction side of the water supply pump can be ensured, and cavitation can be prevented.
Drawings
Fig. 1 is a schematic diagram of a membrane distillation apparatus according to an embodiment.
Fig. 2 is a schematic diagram of a membrane distillation apparatus according to a conventional example.
FIG. 3 is a graph of boiling point versus gauge pressure.
Detailed Description
Fig. 1 shows the structure of a membrane distillation apparatus according to an embodiment.
In this embodiment, a valve 8 for adjusting the pressure difference between the secondary side 17 and the gas phase portion 1a of the water feed tank 1 is provided in the pipe 7 that connects the secondary side 17 of the membrane module 10 and the gas phase portion 1 a. Instead of providing the valve 8 to adjust the pressure difference between the secondary side 17 and the gas phase portion 1a, the diameter of the pipe 7 may be reduced, and the valve 8 may be provided. In addition, the diameter of a part of the pipe 7 can be reduced.
When the diameter of the pipe 7 is reduced, the inner diameter of the pipe 7 is 1/4 (25%) or less of the inner diameter of the vapor pipe 20, preferably 0.5 to 25%, and particularly preferably 1 to 20%. The purpose of the piping 7 is to discharge condensate or precipitate that has remained on the secondary side of the membrane module 10 before or during restarting after stopping the operation of the membrane distillation apparatus, and to hardly affect the operation control of the membrane distillation apparatus even if the inside diameter of the piping 7 is small. On the other hand, when the inner diameter of the pipe 7 is large, frequent opening and closing of the valve 8 is required to stably adjust the pressure difference to a predetermined value, and operation management becomes difficult. In addition, when the valve 8 is closed, condensate or precipitate may remain on the secondary side of the membrane module 10, and stable operation of the membrane distillation apparatus may be a problem.
The length of the piping 7 is 0.2 to 4m, and particularly preferably 0.5 to 2m.
In the present invention, the opening degree of the valve 8 (or the pipe diameter of the pipe 7) is set so that the pressure P of the gas phase portion 1a of the water supply tank detected by the pressure sensor P1 1 And the pressure P of the secondary side 17 in the housing 14 detected by the pressure sensor P2 2 Difference P of (2) 1 -P 2 20 to 90kPa, preferably 20 to 70kPa.
This prevents excessive pressure drop in the gas phase portion 1a, and cavitation on the suction side of the feed pump 2 can be prevented without increasing the water head H of the feed tank 1.
P 2 The gauge pressure (difference from the atmospheric pressure) is preferably about-100 to-40 kPa, and particularly preferably about-100 to-60 kPa.
The other components in fig. 1 are the same as those in fig. 2, and the same reference numerals denote the same parts.
As the hollow fiber 11, a hydrophobic hollow fiber membrane is preferable. The inner diameter (diameter) of the hollow fiber is preferably 0.1 to 3.0mm, particularly preferably 0.5 to 2.0mm, and the difference in thickness, i.e., the outer diameter (radius) and the inner diameter (radius) of the hollow fiber is preferably 0.01 to 1.0mm, particularly preferably 0.1 to 0.5mm. The length of the hollow fibers is 200 to 2000mm, particularly preferably 300 to 1000mm. The filling ratio of the hollow fiber (cross-sectional area of the hollow fiber and/or cross-sectional area of the housing) is preferably 5% to 50%, and particularly preferably 15% to 35%. Examples of the material of the hollow fiber include, but are not limited to, polysulfone, polyethersulfone, polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, and the like.
In the above description, hollow fibers are used, but a hydrophobic flat membrane may also be used.
The treatment solution is preferably an acidic solution such as common salt, phosphoric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid, or the like, an alkali waste solution such as ammonia water, or an aqueous solution such as plating waste water. The water passage speed (linear velocity) of the liquid to be treated in the hollow fiber is preferably 400 to 2000mm/sec, and particularly preferably about 700 to 1500 mm/sec. The temperature of the liquid to be treated when flowing into the membrane module 10 is 45 to 150 ℃, and particularly preferably about 50 to 80 ℃.
The preferable conditions mentioned above represent one preferable example, and the present invention is not limited to the above conditions.
Examples
Comparative example 1
Experimental device and Condition
Measuring the pressure P in the feed water tank when the apparatus shown in FIG. 2 is operated under the following conditions 1 And pressure P on the secondary side of the membrane 2 Is a value of (2). The test conditions were as follows.
Hollow fiber 11: and polytetrafluoroethylene.
1.0mm in inner diameter, 0.3mm in thickness, 600mm in length and 1.
The housing 14 of the membrane module 10: the inner diameter is 10mm and the height is 690mm.
Water supply: naCl 1% aqueous solution.
Feed water temperature: 60 ℃.
Membrane module inlet pressure P 3 : 80kPa (gauge).
Water supply amount: 40mL/min (linear velocity within the hollow fiber 850 mm/sec).
Secondary side pressure P 2 : -90kPa (gauge).
Inner diameter of vapor pipe 20: 6mm.
Inner diameter of the pipe 7: 6mm.
Length of the piping 7: 1m.
Liquid level H:50cm.
< result, investigate >
The pressure in the water feed tank 1 is also rapidly reduced at the same time as the membrane secondary side is depressurized, and the water feed tank pressure P 1 Cavitation occurs at a stage of-70 kPa, and boiling begins at a stage of-80 kPa.
FIG. 3 shows the relationship between the pressure and boiling point of the aqueous solution. According to this relationship, it is believed that boiling occurs at-80 kPa when the feedwater temperature is 60 ℃.
In comparative example 1, cavitation occurred at the stage of-70 kPa, and therefore, it was considered that a liquid surface height of at least 3m was required in order that cavitation did not occur even at the stage of-90 kPa.
Example 1
Experimental device and Condition
A membrane distillation apparatus shown in fig. 1 (the inner diameter of the pipe 7 is 12.5% of the inner diameter of the vapor pipe 20) having the same structure as that of comparative example 1 was used except that the inner diameter of the pipe 7 was set to 0.75mm and a valve 8 capable of adjusting the opening degree was provided in the pipe 7. The opening degree of the valve 8 is adjusted to make the membrane module inlet pressure P 3 Distillation test was conducted under the same conditions as in comparative example 1 except that the pressure was set to-40 kPa (gauge).
< result, review >)
In the present embodiment, the membrane module inlet pressure P is caused by adjusting the opening degree of the valve 8 3 Is-40 kPa, thus P 1 -P 2 At 50kPa, can be run without cavitation of the pump 2.
In addition, since the inner diameter of the pipe 7 in example 1 is sufficiently smaller than that in comparative example 1, the pressure in the water supply tank 1 is reduced at a lower rate than that in the secondary side 17, and the pressure adjustment is easy.
As described above, it was confirmed that by adjusting the pressure of the feed water tank to 20 to 90kPa, the operation was possible without causing cavitation even if the liquid surface height was 50cm.
Although the invention has been described in detail with particular reference to certain embodiments, those skilled in the art will recognize that various changes may be made thereto without departing from the spirit and scope of the invention.
The present application is based on japanese patent application 2020-134727 filed 8/7 in 2020, the entire contents of which are incorporated herein by reference.
Description of the reference numerals
1. Water supply tank
2. Water supply pump
4. 21 heat exchanger
8. Valve
10. Membrane module
11. Hollow fiber
12. 13 potting material
14. Shell body
15. Inflow chamber
16. Outflow chamber
17. Secondary side
25. A pressure reducing device.
Claims (5)
1. A membrane distillation device is characterized in that,
the device comprises: a membrane module, wherein the inside of the housing is divided into a primary side and a secondary side by a hydrophobic membrane;
a liquid circulation supply mechanism having a water supply tank and a water supply pump for circulating and supplying the liquid to be treated to the primary side of the membrane module;
a pressure reducing device configured to reduce pressure on a secondary side of the membrane module; and
a communication mechanism for communicating the secondary side of the membrane module with the gas phase part of the water supply tank,
the pressure difference between the gas phase part of the water supply tank and the secondary side of the membrane module is 20-90 kPa.
2. The membrane distillation apparatus according to claim 1, wherein,
the communication portion has a pressure difference adjusting mechanism that adjusts the pressure difference.
3. A membrane distillation apparatus as claimed in claim 2, wherein,
the communication part having the pressure difference adjusting mechanism is a pipe having a valve.
4. The membrane distillation apparatus according to claim 1, wherein,
the communication portion is a pipe having an inner diameter of 1/4 or less of an inner diameter of a steam pipe connected to the secondary side so as to depressurize the secondary side and suck and discharge steam.
5. A method for operating a membrane distillation apparatus according to claim 3, characterized in that,
the opening degree of the valve is adjusted so that the pressure difference is 20 to 90kPa.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020134727A JP6958687B1 (en) | 2020-08-07 | 2020-08-07 | Membrane distillation equipment and its operation method |
| JP2020-134727 | 2020-08-07 | ||
| PCT/JP2021/011887 WO2022030044A1 (en) | 2020-08-07 | 2021-03-23 | Membrane distillation device and method for operating same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116033959A true CN116033959A (en) | 2023-04-28 |
Family
ID=78281980
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202180056848.4A Pending CN116033959A (en) | 2020-08-07 | 2021-03-23 | Membrane distillation device and method for operating the same |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP6958687B1 (en) |
| CN (1) | CN116033959A (en) |
| WO (1) | WO2022030044A1 (en) |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0352627A (en) * | 1989-07-19 | 1991-03-06 | Hitachi Ltd | Membrane distillation apparatus |
| JP3094505B2 (en) * | 1991-05-27 | 2000-10-03 | 株式会社日立製作所 | Method and apparatus for membrane evaporation and concentration of waste liquid |
| CN1254303C (en) * | 2004-04-27 | 2006-05-03 | 内蒙古工业大学 | Method for increasing flux of membrane distillation and membrane distillation device |
| US20100051549A1 (en) * | 2008-08-29 | 2010-03-04 | Milton Roy Company | Heat recuperating membrane distillation apparatus and system |
| JP2015100776A (en) * | 2013-11-27 | 2015-06-04 | 住友電気工業株式会社 | Wastewater treatment method, membrane distillation module, and wastewater treatment device |
| JP2018083189A (en) * | 2016-05-24 | 2018-05-31 | 旭化成株式会社 | Film distillation apparatus |
| KR101870679B1 (en) * | 2016-06-14 | 2018-06-25 | 한국과학기술연구원 | Membrane distillation system which is capable of real-time monitoring on membrane scaling |
| CN108704484A (en) * | 2018-06-06 | 2018-10-26 | 大连理工大学 | A kind of membrane contactor separation method for polynary pollutant aqueous solution |
-
2020
- 2020-08-07 JP JP2020134727A patent/JP6958687B1/en active Active
-
2021
- 2021-03-23 WO PCT/JP2021/011887 patent/WO2022030044A1/en active Application Filing
- 2021-03-23 CN CN202180056848.4A patent/CN116033959A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| WO2022030044A1 (en) | 2022-02-10 |
| JP6958687B1 (en) | 2021-11-02 |
| JP2022030607A (en) | 2022-02-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106470753B (en) | Vacuum membrane distillation type water making device for ship | |
| KR101692053B1 (en) | Membrane distillation- crystallization system and method | |
| KR101459702B1 (en) | Membrane distillation apparatus by Using waste heat recovery | |
| CN113912019A (en) | Production method of electronic grade hydrogen peroxide aqueous solution | |
| JP5066117B2 (en) | Fresh water production method and apparatus | |
| CN116033959A (en) | Membrane distillation device and method for operating the same | |
| JP2013213660A (en) | Steam plant and method for operating the same | |
| KR20200136814A (en) | Membrane distillation device | |
| CN216259148U (en) | System for producing electronic-grade hydrogen peroxide water solution | |
| JPH0510964B2 (en) | ||
| CN116113488A (en) | Method for operating a membrane distillation plant | |
| US20230398467A1 (en) | Process water distillation plant and method for operating a process water distillation plant | |
| CN215975380U (en) | Mineral spring nanofiltration ultrafiltration liquid concentration extraction equipment | |
| JPH08164328A (en) | Method for cooling filter after steam sterilization | |
| CN113074168B (en) | Hydraulic oil dewatering system and method for side thruster | |
| CN113074169B (en) | Lateral thruster hydraulic oil condensation dewatering system | |
| CN213375984U (en) | Membrane distillation system for preparing pure water by utilizing waste heat | |
| CN221223003U (en) | Heating device | |
| JP2002147972A (en) | Steam heating device | |
| CN219991217U (en) | Water preparation facilities for injection | |
| KR20240049189A (en) | Sterilization method for pharmaceutical water production system | |
| CN211570360U (en) | Anti-permeation membrane permeation filtering device for removing hardness | |
| JP2010284621A (en) | Heat exchanger | |
| CN116147386A (en) | Plate type falling film heat exchange component of nonmetal heat exchange material, MVR evaporation device and preparation method | |
| JP5047426B2 (en) | Steam heating device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |