CN108619868A - Air dehumidifier based on composite micro porous film and dehumidification device - Google Patents

Abstract

The invention discloses a composite microporous membrane dehumidifier, which comprises a terminal head, a flange, a longitudinal middle section shell structure, a pillar, a joint, a cold water inlet and outlet flow channel, and an air inlet and outlet flow channel, and the ends on both sides are fixed membrane wires The two ends of the tube are respectively connected with the cold water inlet and outlet channels through the joints and flanges, so that the low-temperature cold water flows into the inside of the membrane, and the shell structure contains a number of clustered hollow fiber composite microporous membranes and is sealed with the ends on both sides. And the pillars set on the central axis are supporting structures to ensure that the membrane filaments have sufficient mechanical strength, low-temperature cold water enters the interior of the membrane filaments, and exchanges heat with the high-temperature and high-humidity air that enters and exits the air inlet and outlet channels set on the side of the shell structure After that, it is sent into the airtight cabin for use. The invention not only reduces the temperature and humidity of the humid air at the same time, but also realizes the transmission process of water vapor to the cold water under the joint leadership of the capillary force in the micropores of the film layer and the water vapor partial pressure difference, and can directly recycle all the water vapor in the spacecraft cabin precious water vapor.

Description

Air dehumidifier and dehumidification device based on composite microporous membrane

technical field

The invention belongs to the field of spacecraft environment control, and specifically relates to an air dehumidification component and a corresponding system based on a composite microporous membrane of a spacecraft, which solves the problem of precise control of the humidity of the air in the spacecraft cabin, reduces power consumption of air dehumidification, and improves reliability. sex.

Background technique

Humidity control technology is an important aspect of manned spacecraft environmental control and life protection technology, and its basic task is to provide astronauts with a comfortable humidity environment. The relative humidity requirement for astronauts' comfortable environment is 28%-65%. When the relative humidity is lower than 25% or higher than 80%, the working time of astronauts in orbit cannot exceed 12 hours. In addition, due to the small space in the cabin of the manned spacecraft and the large number of electronic equipment, the astronauts continue to produce water vapor due to work and physiological breathing activities. When the relative humidity is high, water vapor may appear on the low-temperature surface of the equipment in the cabin. Condensation and condensation may cause short circuit of electronic equipment, electrochemical corrosion and other consequences, and even endanger the safety of spacecraft; high relative humidity may accelerate the growth and reproduction of microorganisms, increasing the probability of astronauts being infected with diseases. The low relative humidity may cause static electricity. Therefore, it has become an important technology in the field of spacecraft environmental control to accurately control the humidity of the air in the spacecraft cabin, reduce the power consumption of air dehumidification and improve the reliability as much as possible.

Spacecraft humidity control technology has developed from the earliest desiccants, hygroscopic agents and hygroscopic materials to condensation dryers that are widely used in manned spacecraft, space shuttles and space stations. Depending on the amount of activity, the moisture production of astronauts is 50-155g/h, and the average daily moisture production is 1800g. Passive humidity control methods such as desiccants, hygroscopic agents, and hygroscopic materials can no longer meet the development needs of manned spacecraft. The active humidity control technology represented by condensing dryers has developed a lot and has been widely used in manned spacecraft in various countries. The technology is mature, but the air dehumidification method under microgravity is the process of condensation of humid air and separation of gas and water. Separately, it needs to consume more electric power, and there are moving machines, and the condensed water cannot be recycled.

Membrane dehumidification mainly uses the selective permeability of the membrane for gas dehumidification. It has the advantages of continuous dehumidification process, no corrosion problems, no need for valve switching, no moving parts, high system reliability, high separation efficiency, easy maintenance, small pressure drop, and energy efficiency. In recent years, the technology of using the selectivity and permeability of the membrane to dehumidify the air has made great progress.

The Chinese patent "Three-fluid membrane dehumidification device and method" (ZLCN201610170275.9) proposes a coaxial three-fluid membrane dehumidification device. The device is mainly composed of three parts: a membrane tube, a metal casing and a casing. Cold water, humid air, hot water, cold water flows in the innermost membrane tube, moist air flows in the annular channel between the membrane tube and the sleeve, and hot water flows in the annular channel between the sleeve and the casing. The cold water provides a lower water pressure, forming a water vapor partial pressure difference with the humid air with a high water pressure, and the water vapor will enter the cold water through the membrane holes under the action of the water vapor partial pressure difference on both sides of the membrane, so as to achieve the purpose of dehumidification . This method needs to provide cold source and heat source at the same time, the system structure is complicated, and there are many equipments.

The new air dehumidification device and technology using membrane materials are very suitable for application in the environmental control system of spacecraft and have good application prospects. This method not only reduces the temperature and humidity of the humid air at the same time, but also realizes the transmission process of water vapor to cold water under the joint leadership of the capillary force in the micropores of the film layer and the partial pressure difference of water vapor, which not only cleverly overcomes the problem of gas-liquid under microgravity. It can also directly recover all the valuable water vapor in the spacecraft cabin. It can be seen that the application of membrane dehumidification technology in the aerospace field has broad prospects and positive practical significance.

Contents of the invention

The technical problem to be solved by the present invention is to provide an air dehumidification method and equipment that can be used in aerospace microgravity environment, which can simultaneously complete three tasks of humid air enthalpy reduction and dehumidification, gas-liquid separation and water vapor condensation recovery, and satisfy the application of spacecraft need.

In order to solve the above problems, the technical scheme adopted in the present invention is as follows:

The dehumidifier of the composite microporous membrane of the present invention is based on the dehumidification process of the "gas-liquid type" hydrophobic composite microporous membrane: wherein, the composite microporous membrane separates the humid air from the low-temperature cold water, and the low-temperature cold water is on the inner side of the composite membrane Flowing through the pipe, hot and humid air flows through the outer surface of the membrane tube, and water vapor condenses on the low-temperature membrane surface to form a micro-liquid layer. The micro-liquid layer can only absorb water vapor, effectively preventing dry air from entering the film layer; in the micro-liquid layer Under the action of surface tension, the water quickly enters the micropores in the membrane layer, and the liquid water in the micropores seeps into the membrane layer under the joint action of surface tension and internal and external pressure difference, and then undergoes a liquid-vapor phase transition process, and is transformed into water vapor. The form enters the micropores of the film layer, and then diffuses to the cold water side under the combined action of the water vapor pressure gradient and gravity, and finally condenses on the surface of the cold water and is taken away by the cold water, thereby reducing enthalpy and dehumidification of the hot and humid air and separating gas and liquid.

Composite microporous membrane dehumidifier, including ends on both sides, flanges, longitudinal mid-section shell structure, struts, joints, seals, cold water inlet flow, cold water outlet flow, air inlet flow, and air outlet flow The ends on both sides are the two ends of the fixed composite microporous membrane, which are respectively connected with the cold water inlet flow channel and the cold water outlet flow channel through joints and flanges, and ensure that the entrance and exit of each membrane wire are unobstructed, so that Low-temperature cold water smoothly flows into the inside of the membrane filaments, and the longitudinal middle shell structure accommodates a number of longitudinal hollow fiber composite microporous membrane filaments that are tightly packaged at the ends on both sides and is sealed and connected to the ends on both sides. The central axis of the longitudinal middle section structure The pillars set on the top are supporting structures to ensure that several hollow fiber composite microporous membranes have sufficient mechanical strength. Circulation system, the side of the long and middle section shell structure is provided with an air inlet flow channel and an air outlet flow channel at the positions close to the ends of both sides respectively. After heat and mass transfer, the air with reduced temperature and humidity flows out from the air outlet channel and is sent into the sealed cabin for use.

Among them, the hollow fiber membrane is supported by a hydrophobic composite microporous membrane. The inner wall of the membrane tube is a hydrophobic layer. The cold water in the tube cannot penetrate to the outside of the tube under normal or low pressure, ensuring that water vapor enters the membrane after condensing on the surface. , the transmission from the outer wall to the inner wall of the membrane tube is unidirectional.

Wherein, the hollow fiber membrane filaments are fixed in the shell of the middle tube shell structure in the form of clustering and combination, and the two ends are tightly fixed in the ends on both sides.

Among them, the hollow fiber membrane is a hollow structure with a diameter of 1.1mm-1.9mm, and the membrane thickness is variable between 100μm-200μm.

Wherein, the porosity of the microporous membrane of the hollow fiber membrane is 50%-80%.

Wherein, a sealing ring is arranged at the joint between the flange and the joint.

Composite microporous membrane dehumidifier, including composite microporous membrane dehumidifier, fan, water pump, radiation radiator, one-way valve and water collector. The fan sends hot and humid air into the composite microporous membrane dehumidifier. The dehumidifier flows through the outside of the tube bundle of the composite microporous membrane, and the water vapor completes the dehumidification process of reducing enthalpy and dehumidification, becomes cold and dry air, and then re-enters the cabin environment; with the continuous addition of humid air enthalpy, the cold water in the membrane tube As the temperature rises, the heated water flows through the radiation radiator of the spacecraft under the water pump and then lowers its temperature, so that it becomes low-temperature cold water again and enters the cold water inlet channel of the dehumidifier. The water condensed from the cooling water is collected by the one-way valve. Decanter collection.

Among them, during operation, the low-temperature cold water and high-humidity air work in a countercurrent manner, the low-temperature cold water flows in the tube of the hollow fiber membrane, and the high-humidity air flows on the shell side by sweeping the cross-sectional area of the shell, and the end of the air side is directly connected to the wind turbine. The reserved flange interface of the channel, the water side end has a threaded port that can be connected to the water circuit, and is connected to the circulating water circuit through a hose.

The device of the present invention not only reduces the temperature and humidity of humid air at the same time, but also realizes the transmission process of water vapor to cold water under the joint leadership of the capillary force in the micropores of the film layer and the partial pressure difference of water vapor, not only ingeniously overcomes the problem of microgravity. The difficult problem of gas-liquid separation can also directly recover all the valuable water vapor in the spacecraft cabin. It can provide a good practice basis and test basis for the new technology of air humidity control in the spacecraft cabin.

Description of drawings

Fig. 1 is the schematic diagram of water vapor passing through the hollow fiber membrane in the air dehumidification method of the composite microporous membrane of the present invention. .

Fig. 2 is a schematic structural view of the composite microporous membrane dehumidifier of the present invention. As shown in the figure, the dehumidifier adopts a shell-and-tube structure, and the hollow fiber membranes are fixed in the middle section of the dehumidifier in the form of a clustered combination. In the shell, among them, 1. end, 2. flange, 3. shell structure in the middle section, 4. pillar, 5. joint, 6. sealing ring, 7. cold water inlet flow channel, 8. cold water outlet flow channel, 10. Air inlet channel, 9. Air outlet channel, hollow fiber membranes are not marked.

Fig. 3 is a structural schematic diagram of the composite microporous membrane dehumidifier device of the present invention, in which, the composite microporous membrane dehumidifier, fan, water pump, radiation radiator, one-way valve and water collector are composed.

Detailed ways

The composite microporous membrane dehumidification method and device of the present invention will be described in detail below with reference to the accompanying drawings, but the description is only exemplary and not intended to limit the protection scope of the present invention.

Referring to Fig. 1, Fig. 1 has shown the schematic diagram that water vapor passes through hollow fiber membrane silk in the air dehumidification method of composite microporous membrane of the present invention, and water vapor mass transfer process comprises the convective mass transfer of moist air side, diffusion and cold water side convective mass transfer. Among them, the composite membrane separates the humid air from the low-temperature cold water, the low-temperature cold water flows through the permeation side of the composite membrane, the hot and humid air flows through the raw material side outside the membrane tube, and the water vapor condenses into a micro-liquid layer on the low-temperature membrane surface. The micro-liquid layer can only absorb water vapor, which effectively prevents dry air from entering the film layer; the water vapor in the micro-liquid layer quickly enters the micropores in the film layer under the action of surface tension, and the liquid water in the micropores is under surface tension, Under the joint action of internal and external pressure difference, it seeps to the permeate side membrane layer; on the raw material side, water vapor enters the micropores of the hydrophobic membrane layer, diffuses to the permeate side under the action of the water vapor pressure gradient, and finally condenses on the cold water surface It is absorbed and taken away by cold water, so as to achieve the dual purposes of reducing enthalpy and dehumidification of hot and humid air and separating gas and liquid.

Fig. 2 is a sectional view of the composite microporous membrane dehumidifier of the present invention, the composite microporous membrane dehumidifier adopts a shell-and-tube structure, and low-temperature cold water and high-humidity air work in countercurrent form, wherein the composite microporous membrane dehumidifier includes The ends on both sides 1, the flange 2, the longitudinal middle shell structure 3, the pillar 4, the joint 5, the sealing ring 6, the cold water inlet flow channel 7, the cold water outlet flow channel 8, the air inlet flow channel 10 and the air outlet The flow channel 9 is formed, and the ends 1 on both sides are the two ends of the fixed composite microporous membrane, which are respectively connected with the cold water inlet flow channel 7 and the cold water outlet flow channel 8 through the joint 5 and the flange 2, and ensure the The entrance and exit are unobstructed, so that low-temperature cold water flows smoothly into the interior of the membrane filaments, and the longitudinal middle section shell structure 3 accommodates several longitudinal hollow fiber composite microporous membrane filaments tightly packaged at the ends 1 on both sides and is connected to the ends on both sides. 1 Sealed connection, the longitudinal middle section shell structure 3 The pillar 4 set on the central axis is a supporting structure to ensure that the membrane filament has sufficient mechanical strength, and the pillar 4 plays the role of supporting the distance between the two ends, because the membrane filament is Soft unsupported, non-strength hollow fiber membrane, hollow structure with a diameter of 1.1mm-1.9mm, and a variable membrane thickness of 100μm-200μm. Among them, the microporous membranes used to manufacture hollow fiber membranes are mature products on the market or purchased by manufacturers, such as those purchased from Dalian Institute of Physics and Chemistry, Chinese Academy of Sciences, Shandong Dongxu Lantian Environmental Protection Technology Co., Ltd., and Kang Zeyuan (Tianjin) Technology Development Co., Ltd. Products, the difference lies in the performance requirements of the membrane material, membrane tube size, membrane surface pores, etc. The manufacturing method of the hollow fiber membrane can also be manufactured by the known solution spinning method. Among them, the low-temperature cold water enters from the cold water inlet flow channel 7, flows through the end into the inside of the membrane filament, flows out from the cold water outlet flow channel 8, and enters the cold water circulation system. The position is provided with an air inlet flow channel 10 and an air outlet flow channel 9. The air with high temperature and high humidity enters from the air inlet flow channel 10, and after heat and mass transfer with the hollow fiber membrane, the air with reduced temperature and humidity flows from the air outlet. 9 flows out and is sent into the airtight cabin for use.

Fig. 3 is a schematic structural view of the composite microporous membrane dehumidifier device of the present invention, including a dehumidifier, fan, water pump, radiation radiator, one-way valve and water collector. The cold water interface of the dehumidifier is connected to the cold water circulation system, and the water pump is used to realize the circulation of cold water. The heat absorbed from the high-temperature and high-humidity air is taken away by the radiator to maintain the temperature of the cold water. The water absorbed from the high-temperature and high-humidity air passes through The one-way valve is sent into the water collector for collection. The air interface of the dehumidifier is connected to the high-temperature and high-humidity air pipeline system, and the one-way flow of high-temperature and high-humidity air through the dehumidifier is realized through the fan.

On the basis of completing the design, the corresponding experimental research was carried out. When the high-temperature and high-humidity air temperature is 23 degrees, the relative humidity of the air varies between 30% and 70%, the air inlet gauge pressure is 9kPa, and the air flow rate is 76L/min; the cold water inlet temperature is stable at 9°C, and the liquid flow rate is 455mL/min min. Due to the use of countercurrent heat exchange, the temperature of the air drops from about 23°C at the inlet to 15°C, the temperature at the air outlet is relatively stable at 17°C, and the temperature of the cold water rises from 9°C at the inlet to 13°C at the outlet , the outlet temperature of the cold water rose from 11°C to 13°C. The moisture content of the gas inlet was 14 g/kg, while the moisture content of the outlet was stable at 8 g/kg. When using 100 membrane tubes with a surface area of 0.1m ² , the dehumidification capacity is 14.16g/h when the inlet relative humidity is 70%.

Although the specific embodiments of the present invention have been described and illustrated in detail above, it should be pointed out that we can make various equivalent changes and modifications to the above-mentioned embodiments according to the concept of the present invention, and the functional effects produced by it are still the same. Anything beyond the spirit contained in the specification and drawings shall fall within the protection scope of the present invention.

Claims (10)

1. composite micro porous film dehumidifier, including the end of both sides, flange, the stage casing shell structure of lengthwise, pillar, connector, sealing Circle, cold water inlet runner, cooling water outlet runner, air intake runner and air outlet slit runner are constituted, and both sides end is fixed multiple The both ends for closing micropore film wire, are connected to by connector and flange with cold water inlet runner and cooling water outlet runner respectively, and are ensured every It is unobstructed at the entrance and exit of root film wire so that low-temperature cold water smoothly flows into inside film wire, and the stage casing shell structure of lengthwise accommodates Compact package several lengthwises of both sides end the composite microporous film wire of doughnut and with both sides end be tightly connected, lengthwise The pillar being arranged on middle section structure central axis is support structure, it is ensured that several composite microporous film wires of doughnut have enough machines Tool intensity, low-temperature cold water enter from cold water inlet runner, flow through end and enter inside film wire, are flowed out from cooling entrance channel, into Enter cold water circulating system, the position on the stage casing shell structure side of lengthwise respectively close to both sides end is provided with air intake stream The air of road and air outlet slit runner, high temperature and humidity enters from air intake runner, after hollow fiber film thread heat and mass, drop The air of low temperature and humidity is flowed out from air outlet slit runner, is sent into sealed compartment and is used.

2. dehumidifier as described in claim 1, wherein hollow fiber film thread is supported by hydrophobic composite micro porous film, film Inside pipe wall is hydrophobic layer, and the cold water in pipe cannot ensure water vapour on surface under normal or lower pressure to permeating on the outside of pipe Enter in film after condensation, the transmission of membrane tube outer wall inward wall has one-way.

3. dehumidifier as claimed in claim 1 or 2, wherein hollow fiber film thread is fixed on stage casing with cluster combining form and manages In the shell of shell structure, both ends are tightly fixed in the end of both sides.

4. dehumidifier as claimed in claim 3, wherein hollow fiber film thread is hollow-core construction of the diameter in 1.1mm-1.9mm, Film thickness can be changed at 100 μm -200 μm.

5. dehumidifier as claimed in claim 3, wherein the porosity of the microporous barrier of hollow fiber film thread is 50%-80%.

6. dehumidifier as described in claim 1, wherein flange is provided with sealing ring with joint.

7. composite microporous membrane dehumidifier, including claim 1-6 any one of them composite micro porous films dehumidifier, wind turbine, water Hot wet air heating is sent into composite micro porous film dehumidifier by pump, radiator, check valve and water collector, wind turbine, and Hot wet air heating exists On the outside of the tube bank for flowing through composite micro porous film in dehumidifier, water vapour is completed to subtract the dehumidification process of enthalpy dehumidification, after becoming cold dry air Reenter indoor environment；With being continuously added for humid air property heat, the cold water temperature in membrane tube increases, and the water after heating is in water Temperature is reduced after flowing through the radiator of spacecraft under pump pumping, to become the cold water that low-temperature cold water enters dehumidifier again Entrance channel, the water that cooling water condensation goes out are collected by check valve by water collector.

8. composite microporous membrane dehumidifier as claimed in claim 7, wherein when operation, low-temperature cold water and highly humid air are with inverse Manifold formula works, and for low-temperature cold water in the Bottomhole pressure of hollow fiber film thread, highly humid air plunders shell sectional area stream in shell-side with horizontal Dynamic, air side end is directly connected to the reserved flange-interface in air duct, water side head reserve can water receiving road screw thread mouth, pass through hose It is connected to circulation waterway.

9. composite microporous membrane dehumidifier as claimed in claim 7, wherein hollow fiber film thread is completely filled with stage casing shell knot Structure.

10. composite microporous membrane dehumidifier as claimed in claim 7, wherein also set in cold water inlet runner and membrane tube Temperature measuring equipment is equipped with to monitor water temperature.