CN114715976B - Direct contact type membrane distillation device suitable for pure water preparation and pure water preparation method - Google Patents

Direct contact type membrane distillation device suitable for pure water preparation and pure water preparation method Download PDF

Info

Publication number
CN114715976B
CN114715976B CN202210403870.8A CN202210403870A CN114715976B CN 114715976 B CN114715976 B CN 114715976B CN 202210403870 A CN202210403870 A CN 202210403870A CN 114715976 B CN114715976 B CN 114715976B
Authority
CN
China
Prior art keywords
water
raw water
membrane
pool
heating
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.)
Active
Application number
CN202210403870.8A
Other languages
Chinese (zh)
Other versions
CN114715976A (en
Inventor
吴斌鑫
陈龙
戚锐
李伟祥
於少奇
章豪
李霞霞
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Zhejiang University ZJU
Original Assignee
Zhejiang University ZJU
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 Zhejiang University ZJU filed Critical Zhejiang University ZJU
Priority to CN202210403870.8A priority Critical patent/CN114715976B/en
Publication of CN114715976A publication Critical patent/CN114715976A/en
Application granted granted Critical
Publication of CN114715976B publication Critical patent/CN114715976B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • 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
    • B01D61/366—Apparatus therefor
    • 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
    • B01D61/368—Accessories; Auxiliary operations
    • 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
    • C02F1/008—Control or steering systems not provided for elsewhere in subclass C02F
    • 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
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/002—Construction details of the apparatus
    • 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

Landscapes

  • 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)

Abstract

The invention provides a direct contact type membrane distillation device suitable for pure water preparation and a pure water preparation method, wherein the device comprises a raw water side component, a membrane component, a water production side component and a controller; the raw water side assembly comprises a raw water pool and a raw water heating pool which are communicated through a pump, water in the raw water heating pool is heated only during working, a stirring device such as a propeller is installed in the heating pool, and the controller is optimized through computational fluid mechanics analysis, so that water temperature can be rapidly and uniformly, and energy consumption is reduced. The water producing pool of the water producing side component is divided into two stages. The constant temperature refrigeration component only cools a small amount of distilled water participating in membrane distillation circulation in the first stage, and redundant produced water flows into the second stage water producing pool to be naturally cooled, so that the water cooling energy consumption is greatly reduced. The invention realizes automatic monitoring in the whole process, and the system is closed in time when the water level at the feeding and heating side is lower than the safe water level and can not be added, and flux concentration reduction, membrane breakdown and the like caused by membrane pollution occur.

Description

Direct contact type membrane distillation device suitable for pure water preparation and pure water preparation method
Technical Field
The invention belongs to the field of membrane distillation, and technically relates to a direct contact type membrane distillation device suitable for pure water preparation and a pure water preparation method.
Background
Membrane distillation is a new membrane separation process that has emerged in recent years. It is a membrane technology for separating the water solution containing non-volatile solute by using hydrophobic microporous membrane. Liquid water cannot permeate the micropores of the membrane under normal pressure due to the surface tension of water, but water vapor can. When a certain temperature difference exists between the two sides of the membrane, water vapor molecules penetrate through the micropores and are condensed at the other side due to different vapor pressures, so that the solution is gradually concentrated. The process can fully utilize cheap energy sources such as factory heat or solar energy and the like, and is a separation process with practical significance due to easy automation of the process and simple equipment. Since the 1963 s, the technology can be divided into four structures of direct contact membrane distillation, air gap membrane distillation, sweep gas membrane distillation and vacuum membrane distillation according to different condensation modes of volatile components on the membrane permeation side, wherein the direct contact membrane distillation is most widely researched.
The direct contact type membrane distillation is simple to realize and mainly comprises a feed side, a membrane component and a water production side.
On the feed side, the solution to be separated (aqueous solution of non-volatile solute, such as seawater, brackish water, sewage, etc.), heating equipment, pump, etc. are mainly included. The part is mainly used for conveying a solution to be separated into a membrane component by a pump after the solution to be separated is heated to a preset temperature.
The membrane component is a central unit of the membrane distillation system, is a place for carrying out the membrane separation process, and is a carrier of the membrane distillation process. The advantages and disadvantages of the membrane component structure directly affect the separation efficiency and economic performance of membrane distillation. The membrane components commonly used in industry include plate and frame type membrane components, circular tube type membrane components, hollow fiber type membrane components, spiral wound type membrane components, and the like. Among them, the most important of the membrane modules is that a porous hydrophobic membrane is placed therein. The porous hydrophobic membrane commonly used in industry includes Polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE), polyvinylidene fluoride (PVDF), etc., wherein PTFE is used in many applications.
On the water producing side, a water producing pipe, a pump, a condensing device and the like are mainly included. This fraction is mainly to condense the vapor passing through the hydrophobic porous membrane and to collect the liquefied distilled water.
The general disadvantages of the prior art mainly include:
(1) High energy consumption and low membrane distillation flux, and leads to high water production cost. The relevant literature indicates that increasing the feed side temperature is an effective way to increase membrane flux. However, increasing the feed side temperature means increasing the processing cost. And need realize the condensation to vapor through refrigeration plant in the water production side, present direct contact membrane distillation plant is whole to the water of water production side and is cooled down, along with the increase of water production side water yield, the energy consumption is higher and higher to reduce refrigeration effect, can't realize even that water production side temperature control requires.
(2) The process control of membrane distillation is lacked, the related equipment in the prior art needs artificial monitoring control, and when the liquid level at the feeding side is reduced, raw materials need to be added in time for preventing the heating equipment from being dried; when the conductivity of the water producing side is too high, the water body of the current water producing side is polluted, and equipment needs to be stopped immediately and overhauled; continuing to produce water when the membrane flux is low increases the cost of producing water and increases the risk of contamination to the water side, at which point the machine should be shut down in time and replaced with a new membrane.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a direct contact type membrane distillation device suitable for preparing pure water and a pure water preparation method.
The technical scheme of the invention is as follows:
the invention firstly provides a direct contact type membrane distillation device suitable for pure water preparation, which comprises a raw water side component, a membrane component, a water production side component and a controller;
the raw water side assembly comprises a raw water pool, a raw water side water pump, a raw water heating pool and a raw water circulating pump; the raw water pool is connected with the raw water heating pool through a pipeline and a raw water side water pump, and raw water can be pumped to the raw water heating Chi Shanxiang from the raw water pool only; a heating assembly is arranged in the raw water heating tank; and a stirring device;
the raw water heating pool is connected with a raw water inlet of the membrane module through a pipeline and a raw water circulating pump, a raw water outlet of the membrane module is connected with the raw water heating pool through a pipeline, and the raw water heating pool, the raw water circulating pump and the membrane module form raw water side circulation through pipelines;
the water producing side assembly comprises a water producing pump, a first-stage water producing tank, a second-stage water producing tank and an electronic scale; the first-stage water producing tank is connected with a water inlet at a water producing side and a water outlet at the water producing side of the membrane module through a circulating pipeline to form water producing side circulation, and a water producing pump is arranged on the circulating pipeline;
the water outlet of the first-stage water producing pool is positioned at the set height of the first-stage water producing pool, the first-stage water producing pool is connected with the water inlet of the second-stage water producing pool through the water outlet, when the water level in the first-stage water producing pool is higher than the height of the water outlet, water flows into the second-stage water producing pool from the first-stage water producing pool in a one-way mode, and the second-stage water producing pool is arranged on the electronic scale; a constant-temperature refrigeration assembly is arranged in the first-stage water producing tank;
the controller is respectively connected with the raw water side water pump, the raw water circulating pump, the heating assembly, the stirring device, the water production pump and the constant-temperature refrigerating assembly for control, and is connected with the electronic scale to acquire a weighing signal; the controller is also provided with a buzzer.
Further, the membrane module comprises a raw water side membrane pool, a produced water membrane measuring pool, a hydrophobic porous membrane and a supporting grid, wherein the hydrophobic porous membrane and the supporting grid are arranged between the raw water side membrane pool and the produced water membrane measuring pool; the hydrophobic porous membrane is arranged on the support grid, and a raw water inlet and a raw water outlet are formed in the raw water side membrane pool; the water production and measurement membrane pool is provided with a water production and measurement water inlet and a water production and measurement water outlet.
Furthermore, the membrane assembly further comprises a membrane assembly upper cover plate and a membrane assembly lower cover plate, and the membrane assembly upper cover plate and the membrane assembly lower cover plate are fixed on the upper surface and the lower surface of the membrane assembly through bolts respectively to encapsulate the membrane assembly.
Furthermore, the hydrophobic porous membrane is made of PTFE, PP, PE or PVDF.
Furthermore, a liquid level meter is also arranged in the raw water heating pool and is connected with the controller, and the liquid level meter is used for acquiring the liquid level height in the raw water heating pool and transmitting the liquid level height to the controller; when the liquid level of the raw water heating pool still cannot reach the working safety water level under the condition that the raw water side water pump works, the controller controls the heating assembly to stop heating, the raw water circulating pump and the water producing water pump are turned off, and the buzzer gives an alarm.
Further, a conductivity sensor is arranged at an inlet of the first-stage water producing tank, and when the conductivity detected by the conductivity sensor is higher than a preset value or the detected conductivity is suddenly increased, the raw water circulating pump and the water producing pump are turned off, and a buzzer gives an alarm.
The invention also provides a pure water preparation method based on the device, wherein a liquid level meter is also arranged in the raw water heating tank, and a conductivity sensor is arranged at an inlet of the first-stage water producing tank; the method comprises the following steps:
1) Raw water is filled in the raw water pool and the raw water heating pool, and the water quantity is ensured to be more than or equal to the safe water level and water quantity of the raw water heating pool;
2) Adding purified water into the first-stage water producing pond to reach the necessary water amount required by water producing circulation;
3) Starting a controller, and setting the temperature of a raw water heating pool at 60-80 ℃ and the temperature of a first-stage water producing pool at 20-40 ℃;
4) Starting the heating assembly of the raw water heating pool, starting the stirring device, and giving the optimal working parameters of the heating assembly and the stirring device in the heating process of the raw water heating pool by the controller through computational fluid dynamics analysis, so that the heating energy consumption is reduced, and the overall water temperature is monitored; the constant-temperature refrigeration component cools the purified water in the first-stage water producing tank; when the temperature of raw water heating Chi Zhongyuan and the temperature in a first-stage water producing pool on a water producing side reach preset ranges, a controller starts a raw water circulating pump and a water producing pump to start pure water preparation;
5) The water in the first-stage water producing pond participates in water producing circulation, when the water amount in the first-stage water producing pond is higher than the outlet height of the first-stage water producing pond, the water enters the second-stage water producing pond, and the water in the second-stage water producing pond does not participate in the water producing circulation;
6) In the working process, the liquid level meter monitors the water level of the raw water heating pool in real time, and when the water level is lower than a first set threshold, the raw water side water pump starts to work and automatically fills raw water into the raw water heating pool; when the water level is lower than the safe water level, the liquid level meter feeds back a signal to the controller, the controller controls the heating assembly to stop heating, the raw water circulating pump and the water producing pump are turned off, and the buzzer gives an alarm; wherein the first set threshold is higher than a safe water level; the conductivity sensor monitors the conductivity of the produced water entering the first-stage water producing pool in real time, and when the conductivity is higher than a preset value or the conductivity is detected to be suddenly increased, the raw water circulating pump and the produced water pump are closed, and a buzzer gives an alarm; meanwhile, the controller detects the membrane flux on the water production side in real time through the weight change of the electronic scale, and when the membrane flux is smaller than a system preset value or a user set value, the raw water circulating pump and the water production pump are closed, and the operation is stopped.
Compared with the prior art, the invention at least has the following beneficial effects:
(1) Because the invention carries out two-stage treatment on the raw material side and the water producing side, and adds the functions of liquid level detection, automatic water supply and the like, the heating and refrigerating process is optimized, and the conditions that dry burning and even equipment damage are caused due to too low liquid level, the refrigerating energy consumption of the water producing side is high, and the refrigerating effect can not reach the control requirement in the existing equipment are avoided.
(2) Because the invention realizes automatic monitoring in the whole process, when the water level at the feeding heating side is lower than the safe water level and can not be added continuously, flux concentration reduction caused by membrane pollution, membrane breakdown and the like occur, the system is closed in time. Therefore, the situations that in the prior art, the water body on the water production side is polluted and the membrane flux is reduced to cause the increase of the water production cost and the like due to untimely detection and untimely monitoring are overcome.
Drawings
FIG. 1 is a schematic diagram of the structure of a direct contact membrane distillation apparatus according to the present invention;
FIG. 2 is a schematic structural diagram of a membrane module of the present invention.
In the figure, 1, a controller; 2. a raw water pool; 3. a raw water side water pump; 4. a raw water heating tank; 5. a heating assembly; 6. a propeller; 7. a raw water circulating pump; 8. a membrane module; 9. a water producing pump; 10. a constant temperature refrigeration component; 11. a first-stage water producing tank; 12. a second-stage water producing tank; 13. an electronic scale; 14. a membrane module upper cover plate; 15. a raw water inlet; 16. a raw water outlet; 17. a hydrophobic porous membrane; 18. supporting the grid; 19. a water production membrane measuring pool; 20. a raw water side membrane pool; 21. a membrane module lower cover plate; 22. a water inlet at the water producing side; 23. a water outlet at the water producing side; 24. fixing the bolt; 25. a raw water side bolt hole; 26. and a water producing side bolt hole.
Detailed Description
The invention will be further illustrated and described with reference to specific embodiments. The described embodiments are merely exemplary of the disclosure and are not intended to limit the scope thereof. The technical features of the embodiments of the present invention can be combined correspondingly without mutual conflict.
As shown in fig. 1, the direct contact membrane distillation apparatus suitable for pure water production illustrated in the present embodiment includes a raw water side module, a membrane module 8, a water production side module, and a controller 1;
the raw water side assembly comprises a raw water pool 2, a raw water side water pump 3, a raw water heating pool 4 and a raw water circulating pump 7; the raw water pool 2 is connected with the raw water heating pool through a pipeline and a raw water side water pump 3, and raw water can be pumped from the raw water pool 2 to the raw water heating Chi Shanxiang; a heating assembly 5 is arranged in the raw water heating tank; and a stirring device; the raw water heating tank 4 is connected with a raw water inlet of the membrane module 8 through a pipeline and a raw water circulating pump 7, a raw water outlet of the membrane module 8 is connected with the raw water heating tank through a pipeline, and the raw water heating tank 4, the raw water circulating pump 7 and the membrane module 8 form raw water side circulation through pipelines;
the water producing side assembly comprises a water producing pump 9, a first-stage water producing tank 11, a second-stage water producing tank 12 and an electronic scale 13; the first-stage water producing tank 11 is connected with a water producing side water inlet and a water producing side water outlet of the membrane module 8 through a circulating pipeline to form water producing side circulation, and a water producing pump 9 is arranged on the circulating pipeline; the water outlet of the first-stage water producing tank 11 is positioned at the set height of the first-stage water producing tank 11, the first-stage water producing tank 11 is connected with the water inlet of the second-stage water producing tank 12 through the water outlet, when the water level in the first-stage water producing tank 11 is higher than the water outlet, water flows into the second-stage water producing tank 12 from the first-stage water producing tank 11 in a one-way mode, and the second-stage water producing tank 12 is arranged on the electronic scale 13; a constant-temperature refrigeration assembly 10 is arranged in the first-stage water producing tank 11;
the controller 1 is respectively connected with a raw water side water pump 3, a raw water circulating pump 7, a heating assembly 5, a stirring device, a produced water pump 9 and a constant temperature refrigerating assembly 10 for control, and the controller 1 is connected with an electronic scale 13 to obtain a weighing signal; the controller 1 is also provided with a buzzer.
Further, a liquid level meter is arranged in the raw water heating pool 4 and connected with the controller 1, and the liquid level meter is used for acquiring the liquid level height in the raw water heating pool 4 and transmitting the liquid level height to the controller 1; when the raw water side water pump 3 works and the liquid level of the raw water heating pool 4 still cannot reach the working safety water level, the controller controls the heating component 5 to stop heating, and the buzzer gives an alarm.
Further, a conductivity sensor is provided at an inlet of the first-stage water producing tank 11, and a buzzer alarms when the conductivity detected by the conductivity sensor is higher than a preset value or the detected conductivity suddenly and rapidly rises.
As shown in fig. 2, the membrane module 8 comprises a raw water side membrane pool 20, a produced water side membrane pool 19, and a hydrophobic porous membrane 17 and a support grid 18 which are arranged between the raw water side membrane pool and the produced water side membrane pool; wherein the hydrophobic porous membrane 17 is arranged on the supporting grid 18, and the raw water side membrane pool 20 is provided with a raw water inlet 15 and a raw water outlet 16; the water production measuring film pool 19 is provided with a water production measuring water inlet 22 and a water production measuring water outlet 23. The membrane module 8 further comprises a membrane module upper cover plate 14 and a membrane module lower cover plate 21, wherein the membrane module upper cover plate 14 and the membrane module lower cover plate 21 are respectively fixed on the upper surface and the lower surface of the membrane module through fixing bolts 24, raw water side bolt holes 25 and water production side bolt holes 26 to encapsulate the membrane module. The material of the hydrophobic porous membrane 17 is PTFE, PP, PE, or PVDF. The total height of the membrane component is between 1 and 3 mm. The type, number, position and the like of the bolts can be adjusted according to actual conditions.
In the invention, the controller gives the optimal working parameters of the heating rod and the propeller in the heating process through computational fluid dynamics analysis (CFD), reduces the heating energy consumption of the system and realizes constant temperature control (+/-0.5-1 ℃).
The models of the controller, the upper computer, the pipeline and other components can be selected according to actual requirements. Wherein the level sensor on the heating side can be replaced by a scale. Namely, a scale is arranged below the raw water heating side water tank. When the whole weight is less than a certain set value, the detection value is equal to the detection value of the liquid level sensor.
The preparation of pure water using the apparatus shown in FIG. 1 can be carried out as follows:
1) Raw water is filled in the raw water pool and the raw water heating pool, and the water quantity is ensured to be more than or equal to the safe water level and water quantity of the raw water heating pool;
2) Adding purified water into the first-stage water producing pond to reach the necessary water amount required by water producing circulation; (the conductivity is less than or equal to 10 mu s/cm optimal);
3) Starting a controller, setting the temperature of a raw water heating pool at 60-80 ℃ and the temperature of a first-stage water producing pool at 20-40 ℃, and further presetting the working flow of a raw water side peristaltic pump, the working flow of a water producing side peristaltic pump and the estimated water level of a water producing side (the default is that the water producing pool is full);
4) Starting a heating assembly of the raw water heating pool, starting a stirring device, giving the optimal working parameters of the heating assembly and the stirring device of the raw water heating pool in the heating process by a controller through Computational Fluid Dynamics (CFD), reducing the heating energy consumption, and monitoring the whole water temperature; the constant-temperature refrigeration component cools the purified water in the first-stage water producing tank; when the temperature of raw water heating Chi Zhongyuan and the temperature in a first-stage water producing pool on a water producing side reach preset ranges, a controller starts a raw water circulating pump and a water producing pump to start pure water preparation;
5) Water in the first-stage water producing pool participates in water producing circulation, when the water amount in the first-stage water producing pool is higher than the height of an outlet of the first-stage water producing pool, water enters the second-stage water producing pool, and the water in the second-stage water producing pool does not participate in the water producing circulation;
6) In the working process, the liquid level meter monitors the water level of the raw water heating pool in real time, and when the water level is lower than a first set threshold, the raw water side water pump starts to work and automatically fills raw water into the raw water heating pool; when the water level is lower than the safe water level, the liquid level meter feeds back a signal to the controller, the controller controls the heating component 5 to stop heating, the raw water circulating pump and the water producing pump are turned off, and the buzzer gives an alarm; wherein the first set threshold is higher than a safe water level;
the conductivity sensor monitors the conductivity of the produced water entering the first-stage water producing tank in real time, and when the conductivity is higher than a preset value or the conductivity is detected to be suddenly increased, the raw water circulating pump and the produced water pump are closed, and a buzzer gives an alarm;
meanwhile, the controller detects the membrane flux on the water production side in real time through the weight change of the electronic scale, and when the membrane flux is smaller than a system preset value or a user set value, the raw water circulating pump and the water production pump are closed, and the operation is stopped.
Wherein, the membrane flux calculation formula is as follows:
J＝M/(S·T) (1)
wherein J represents the membrane flux in kg/m 2 H; m represents total produced water weight in kg; s represents the effective area of the membrane in the membrane module, unit m 2 (ii) a T represents the distillation time in h.
The invention divides the raw material side into two parts, including a raw water pool and a raw water heating pool, and the two groups of equipment are communicated through a pump. When the system works, only the water in the raw water heating pool is heated. And a stirring device such as a propeller is arranged in the heating pool, and the controller is optimized through computational fluid mechanics analysis, so that the water temperature can be quickly and uniformly, and the energy consumption is reduced. The water producing side is divided into a constant temperature refrigeration component and a water producing pool. The water producing pool is divided into two stages. The constant-temperature refrigeration assembly cools only a small amount of distilled water participating in membrane distillation circulation in the first stage, and redundant produced water flows into the second-stage water producing tank to be naturally cooled, so that the water cooling energy consumption is greatly reduced, and the constant-temperature refrigeration assembly is suitable for preparing industrial pure water.
In the normal working process of the system, the water level of the raw material side is continuously reduced due to heating, water production by distillation and the like. When the water level is lowered to a safe level, the heating equipment is easy to dry and even damaged. In order to solve the problem, the raw material side is divided into two parts, including a raw water pool and a raw water heating pool, and the two groups of equipment are communicated through a pump. Adding a liquid level sensor into the raw water heating pool, starting the raw water side water pump 3 when the water level is lower than the safe water level, and continuing water from the raw water pool to the raw water heating pool until a first set threshold (the first set threshold can be selected as a full water level) is reached; when the water level of the raw water heating pool cannot be increased to a safe level after the raw water side water pump 3 is started, the system automatically turns off the heating function. When the temperature of the heating raw water pool is lower than the preset minimum working temperature, the whole system automatically stops working.
In the working process of the system, if the hydrophobic porous membrane in the membrane component is polluted by sewage, the membrane flux will be continuously reduced. When the contamination is severe, film breakdown may even occur. Namely, the two sides of the membrane are communicated, and the conductivity of the water producing side can generate surging at the moment, and the water body on the water producing side is polluted. Therefore, the above problems are solved. The invention arranges the conductivity sensor, the balance and other equipment on the water producing side, and monitors the membrane flux and conductivity change of the system in real time in the working process. When the membrane flux is reduced to a set value or the conductivity of the water production side is suddenly increased (when the change rate of the conductivity is larger than a set threshold value), the system gives an alarm and stops working.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is specific and detailed, but not to be understood as limiting the scope of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

Claims (8)

1. A direct contact type membrane distillation device suitable for pure water preparation is characterized by comprising a raw water side component, a membrane component (8), a water production side component and a controller (1);
the raw water side assembly comprises a raw water pool (2), a raw water side water pump (3), a raw water heating pool (4) and a raw water circulating pump (7); the raw water pool (2) is connected with the raw water heating pool through a pipeline and a raw water side water pump (3), and raw water can be pumped to the raw water heating Chi Shanxiang from the raw water pool (2); a heating component (5) and a stirring device are arranged in the raw water heating tank;
the raw water heating tank (4) is connected with a raw water inlet of the membrane component (8) through a pipeline and a raw water circulating pump (7), a raw water outlet of the membrane component (8) is connected with the raw water heating tank through a pipeline, and the raw water heating tank (4), the raw water circulating pump (7) and the membrane component (8) form raw water side circulation through pipelines;
the water producing side assembly comprises a water producing pump (9), a first-stage water producing tank (11), a second-stage water producing tank (12) and an electronic scale (13); the first-stage water producing tank (11) is connected with a water inlet at a water producing side and a water outlet at the water producing side of the membrane component (8) through a circulating pipeline to form water producing side circulation, and a water producing pump (9) is arranged on the circulating pipeline;
the water outlet of the first-stage water producing tank (11) is positioned at the set height of the first-stage water producing tank (11), the first-stage water producing tank (11) is connected with the water inlet of the second-stage water producing tank (12) through the water outlet, when the water level in the first-stage water producing tank (11) is higher than the height of the water outlet, water flows into the second-stage water producing tank (12) from the first-stage water producing tank (11) in a one-way mode, and the second-stage water producing tank (12) is arranged on the electronic scale (13); a constant-temperature refrigeration assembly (10) is arranged in the first-stage water producing tank (11);
the controller (1) is respectively connected with the raw water side water pump (3), the raw water circulating pump (7), the heating assembly (5), the stirring device, the water producing water pump (9) and the constant temperature refrigerating assembly (10) for control, and the controller (1) is connected with the electronic scale (13) to obtain a weighing signal; the controller (1) is also provided with a buzzer.
2. The direct contact membrane distillation apparatus suitable for pure water production according to claim 1, wherein the membrane module (8) comprises a raw water side membrane tank (20), a water production side membrane tank (19), and a hydrophobic porous membrane (17) and a support grid (18) arranged between the raw water side membrane tank and the water production side membrane tank; wherein the hydrophobic porous membrane (17) is arranged on the supporting grid (18), and the raw water inlet (15) and the raw water outlet (16) are arranged on the raw water side membrane pool (20); a water inlet (22) at the water producing side and a water outlet (23) at the water producing side are arranged on the water producing side membrane pool (19).
3. The direct contact membrane distillation device suitable for pure water preparation according to claim 2, wherein the membrane module (8) further comprises a membrane module upper cover plate (14) and a membrane module lower cover plate (21), and the membrane module upper cover plate (14) and the membrane module lower cover plate (21) are respectively fixed on the upper surface and the lower surface of the membrane module through bolts to encapsulate the membrane module.
4. The direct contact membrane distillation apparatus for pure water production according to claim 2, wherein the hydrophobic porous membrane (17) is made of PTFE, PP, PE or PVDF.
5. The direct contact membrane distillation apparatus suitable for pure water preparation according to claim 1, wherein a liquid level meter is further disposed in the raw water heating tank (4), and the liquid level meter is connected to the controller (1) and is used for acquiring the liquid level height in the raw water heating tank (4) and transmitting the liquid level height to the controller (1); when the liquid level of the raw water heating pool (4) still cannot reach the working safety water level under the condition that the raw water side water pump (3) works, the controller controls the heating component (5) to stop heating, the raw water circulating pump and the water producing water pump are turned off, and the buzzer gives an alarm.
6. The direct contact membrane distillation apparatus for pure water production according to claim 1, wherein a conductivity sensor is provided at the inlet of the first stage water producing tank (11), and when the conductivity detected by the conductivity sensor is higher than a preset value or a sudden rise of the detected conductivity, the raw water circulating pump and the produced water pump are turned off and a buzzer alarms.
7. A pure water preparation method based on the device of claim 1, characterized in that a liquid level meter is arranged in the raw water heating pool (4), and a conductivity sensor is arranged at the inlet of the first-stage water producing pool (11); the method comprises the following steps:
1) Raw water is filled in the raw water pool and the raw water heating pool, and the water quantity is ensured to be more than or equal to the safe water level and water quantity of the raw water heating pool;
2) Adding purified water into the first-stage water producing pond to reach the necessary water amount required by water producing circulation;
3) Starting a controller, and setting the temperature of a raw water heating pool at 60-80 ℃ and the temperature of a first-stage water producing pool at 20-40 ℃;
4) Starting a heating assembly of the raw water heating pool, starting a stirring device, giving the optimal working parameters of the heating assembly and the stirring device in the heating process of the raw water heating pool by a controller through Computational Fluid Dynamics (CFD), reducing heating energy consumption and monitoring the whole water temperature; the constant-temperature refrigeration component cools the purified water in the first-stage water producing tank; when the temperature of raw water heating Chi Zhongyuan and the temperature in a first-stage water producing pool on a water producing side reach preset ranges, a controller starts a raw water circulating pump and a water producing pump to start pure water preparation;
5) The water in the first-stage water producing pond participates in water producing circulation, when the water amount in the first-stage water producing pond is higher than the outlet height of the first-stage water producing pond, the water enters the second-stage water producing pond, and the water in the second-stage water producing pond does not participate in the water producing circulation;
6) In the working process, the liquid level meter monitors the water level of the raw water heating pool in real time, and when the water level is lower than a first set threshold, the raw water side water pump starts to work and automatically fills raw water into the raw water heating pool; when the water level is lower than the safe water level, the liquid level meter feeds back a signal to the controller, the controller controls the heating component (5) to stop heating, the raw water circulating pump and the water producing pump are turned off, and the buzzer gives an alarm; wherein the first set threshold is higher than a safe water level; the conductivity sensor monitors the conductivity of the produced water entering the first-stage water producing pool in real time, and when the conductivity is higher than a preset value or the conductivity is detected to be suddenly increased, the raw water circulating pump and the produced water pump are closed, and a buzzer gives an alarm; meanwhile, the controller detects the membrane flux on the water production side in real time through the weight change of the electronic scale, and when the membrane flux is smaller than a system preset value or a user set value, the raw water circulating pump and the water production pump are closed, and the operation is stopped.
8. The pure water production method according to claim 7, wherein the membrane flux calculation formula is:
J＝M/(S·T) (1)
wherein J represents the membrane flux in kg/m 2 H; m represents total produced water weight in kg; s represents the effective area of the membrane in the membrane module, unit m 2 (ii) a T represents the distillation time in h.
CN202210403870.8A 2022-04-18 2022-04-18 Direct contact type membrane distillation device suitable for pure water preparation and pure water preparation method Active CN114715976B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210403870.8A CN114715976B (en) 2022-04-18 2022-04-18 Direct contact type membrane distillation device suitable for pure water preparation and pure water preparation method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210403870.8A CN114715976B (en) 2022-04-18 2022-04-18 Direct contact type membrane distillation device suitable for pure water preparation and pure water preparation method

Publications (2)

Publication Number Publication Date
CN114715976A CN114715976A (en) 2022-07-08
CN114715976B true CN114715976B (en) 2023-01-24

Family

ID=82243068

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210403870.8A Active CN114715976B (en) 2022-04-18 2022-04-18 Direct contact type membrane distillation device suitable for pure water preparation and pure water preparation method

Country Status (1)

Country Link
CN (1) CN114715976B (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008212834A (en) * 2007-03-05 2008-09-18 Matsushita Electric Ind Co Ltd Pure water production method and device
CN101659451A (en) * 2008-08-29 2010-03-03 北京清大国华环保科技有限公司 Method for treating high-salt water by air stripping type membrane distillation
CN102417210A (en) * 2010-09-28 2012-04-18 中国石油化工股份有限公司 Immersed vacuum membrane distillation plant and sewage treatment technology using the same
CN106241961A (en) * 2016-09-06 2016-12-21 大唐环境产业集团股份有限公司 A kind of water treatment facilities utilizing residual heat of electric power plant and method
CN111689539A (en) * 2019-03-14 2020-09-22 上海江柘环境工程技术有限公司 Membrane distillation process for advanced treatment of high-concentration desulfurization wastewater concentrated solution of power plant

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008212834A (en) * 2007-03-05 2008-09-18 Matsushita Electric Ind Co Ltd Pure water production method and device
CN101659451A (en) * 2008-08-29 2010-03-03 北京清大国华环保科技有限公司 Method for treating high-salt water by air stripping type membrane distillation
CN102417210A (en) * 2010-09-28 2012-04-18 中国石油化工股份有限公司 Immersed vacuum membrane distillation plant and sewage treatment technology using the same
CN106241961A (en) * 2016-09-06 2016-12-21 大唐环境产业集团股份有限公司 A kind of water treatment facilities utilizing residual heat of electric power plant and method
CN111689539A (en) * 2019-03-14 2020-09-22 上海江柘环境工程技术有限公司 Membrane distillation process for advanced treatment of high-concentration desulfurization wastewater concentrated solution of power plant

Also Published As

Publication number Publication date
CN114715976A (en) 2022-07-08

Similar Documents

Publication Publication Date Title
CN102065964B (en) System for decontaminating water and generating water vapor
Wang et al. Feasibility research of potable water production via solar-heated hollow fiber membrane distillation system
CN110055547B (en) Water electrolysis hydrogen production device
CN101882350B (en) Water pollution organism early warning system and method based on principle of microbial fuel cells
CN115072893B (en) Grease-containing wastewater treatment device and grease-containing wastewater treatment method
CN114715976B (en) Direct contact type membrane distillation device suitable for pure water preparation and pure water preparation method
Kargari et al. Water desalination: Solar-assisted membrane distillation
Al-Bastak et al. Periodic operation of a reverse osmosis water desalination unit
CN108726636A (en) A kind of method and system of membrane distillation processing waste water
CN209917639U (en) Ceramic flat plate membrane flux testing device
CN206799222U (en) A kind of membrane treatment appts of sanitary sewage
JP3894034B2 (en) Concentration method of sludge
CN217398877U (en) Anaerobic fermentation reactor
CN215975380U (en) Mineral spring nanofiltration ultrafiltration liquid concentration extraction equipment
CN111939583B (en) A safe type distillation column device for ethanol extraction
JPH10180254A (en) Method and device for producing pure water
CN106512660B (en) Intelligent hydramine decarbonization system and method based on multi input Fuzzy PID
CN114806858A (en) Device and method for recovering volatile fatty acid in anaerobic fermentation system
CN205313483U (en) Marsh gas purification unit
CN213699482U (en) Water treatment membrane performance testing device
CN210796085U (en) Temperature compensation system of water treatment system
KR101332684B1 (en) Membrane water treatment device having air ejector
RU2341590C2 (en) Hydrogen production device
CN110734167A (en) high-difficulty sewage treatment system
CN220485405U (en) System for simultaneously producing desalted and deoxidized water and oxygen-enriched water by utilizing seawater

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
GR01 Patent grant
GR01 Patent grant
CB03 Change of inventor or designer information
CB03 Change of inventor or designer information

Inventor after: Chen Long

Inventor after: Wu Binxin

Inventor after: Qi Rui

Inventor after: Li Weixiang

Inventor after: Yu Shaoqi

Inventor after: Zhang Hao

Inventor after: Li Xiaxia

Inventor before: Wu Binxin

Inventor before: Chen Long

Inventor before: Qi Rui

Inventor before: Li Weixiang

Inventor before: Yu Shaoqi

Inventor before: Zhang Hao

Inventor before: Li Xiaxia