JP5680456B2 - Dehumidifying air conditioner - Google Patents

Description

  The present invention relates to a dehumidifying air conditioner suitable for a lithium battery manufacturing plant.

  A lithium battery manufacturing plant will cause a problem in the quality of the lithium battery unless it is dehumidified. That is, lithium reacts strongly with moisture, and a lithium battery manufacturing plant needs to set the dew point to -40 degrees Celsius or less (hereinafter, all temperatures are set to "Celsius").

  In order to create an environment with such a low dew point, generally means is used which vaporizes liquid nitrogen and replaces the air in the plant with nitrogen, or uses an adsorption-type dehumidifying air conditioner using a moisture adsorbent. In the method of replacing air with nitrogen, there is a problem that it becomes impossible for a person to enter the plant, and the running cost is high, so it is practical to use an adsorption type dehumidifying air conditioner, and many plants have This means is used.

  However, there is a demand to reduce the cost of the lithium battery as much as possible, and energy consumption in the manufacturing process needs to be as low as possible. Therefore, it is necessary to save energy while maintaining the capability of the dehumidifying air conditioner. On the other hand, since volatile components of the electrolyte of the lithium battery are generated in the plant, ventilation is also necessary. Therefore, it is necessary to reduce energy lost with ventilation. In response to such a request, there has been a technique disclosed in Patent Document 1.

  The one disclosed in Patent Document 1 maintains the indoor environment at a low dew point while ventilating indoor air. By the way, in the manufacturing process of the lithium battery, as disclosed in Patent Document 2, hydrofluoric acid may be generated. In other words, LiPF6 (lithium hexafluorophosphate), LiBF4 (lithium tetrafluorooxalate), or the like may be used as the electrolyte of the lithium battery. In such a case, fluoride in the atmosphere of the production plant. Fluorine gas such as hydrogen may be generated. In addition, phosphoric acid-based gas may be generated.

  Here, zeolite or silica gel is used as the moisture adsorbent of the adsorption-type dehumidifying air conditioner. These moisture adsorbents have silicon oxide as a main component, and when they come into contact with a fluorine-based gas, there is a problem that the performance as a moisture adsorbent is impaired due to silicon fluoride.

  Further, glass fibers and ceramic fibers are used for the paper constituting the honeycomb rotor, and there has been a problem that the fluorine-based gas damages the glass fibers and the phosphoric acid-based gas damages the ceramic fibers.

JP 2004-116854 A JP 2004-175659 A

  The problem to be solved is that the performance of the adsorption-type dehumidifying air conditioner is impaired by the fluorine-based gas.

  In the present invention, the total heat exchange rotor that withstands fluorine-based gas dehumidifies the air that has undergone total heat exchange between the return air from the dry room and the outside air. Even when used in a generated atmosphere, the most important feature is that the moisture adsorbent is impaired in performance by the fluorine-based gas and the honeycomb rotor is not damaged by the phosphoric acid-based gas.

  The dehumidifying air conditioner of the present invention achieves energy saving by using the return air from the dry room, that is, the dry air exhausted from the dry room, even if the return air contains a fluorine-based gas. A dehumidifying air conditioner that does not affect the adsorbent can be obtained.

  That is, the humidity in the air in the dry room gradually increases due to the humidity contained in the exhaled air, for example, when there is a person. For this reason, when the air in the dry room is returned to the dehumidifying air conditioner as return air, the dehumidifying air conditioner only needs to remove the moisture that has increased due to the humidity load, so dehumidification can be performed with less energy. In some cases, the dehumidifying rotor may be damaged by fluorine gas or the like in the return air. Also, if there are people in the dry room, ventilation is necessary due to health problems.

  According to the present invention, it is possible to save energy while supplying fresh fresh air to the dry room and exhausting the entire amount of return air from the dry room.

  In addition, since the return air from the dry room does not return to the dehumidification rotor, the dehumidification rotor is not damaged even if fluorine gas is mixed in the return air.

  Furthermore, even when gas that may adversely affect the human body is generated in the dry room, it is ventilated with fresh air, so there are workers in the dry room. There is no problem.

FIG. 1 is an explanatory diagram showing an implementation method of the dehumidifying air conditioner. Example 1 FIG. 2 is an explanatory diagram showing an implementation method of the dehumidifying air conditioner. (Example 2)

  Even when used in an atmosphere where fluorine-based gas is generated, the objective of preventing the moisture adsorbent from being impaired by the fluorine-based gas has been achieved while saving energy by using return air from the dry room.

  A description will be given with reference to FIG. Reference numeral 1 denotes a non-silica total heat exchange rotor that does not use silica such as silica gel or zeolite as a moisture absorbent. For example, as shown in Japanese Patent Application Laid-Open No. 07-159068, an ion exchange resin powder carried on an aluminum sheet and formed into a honeycomb shape is suitable. That is, the ion exchange resin functions as a moisture adsorbent, but the performance is not impaired by the fluorine-based gas. The total heat exchange rotor 1 is divided into two zones, zone A2 and zone B3.

  Outside air OA is fed into the zone A2 by the blower 4. Further, air is sucked from the zone B3 by the blower 5 and released into the atmosphere. In the zone B3, the return air from the dry room 5 is sent. As a result, the outside air OA and the return air from the dry room 5 are totally heat-exchanged, and the return air is released into the atmosphere as exhaust EA.

  Reference numeral 7 denotes an evaporator of a refrigerator using carbon dioxide, ammonia or the like as a refrigerant, which cools the outside air that has been subjected to total heat exchange and dehumidifies it by condensation. Although the refrigerator has a compressor and a radiator, the description is omitted because it is common. Reference numeral 8 denotes a dehumidifying rotor, on which silica gel is supported as a moisture adsorbent. The dehumidifying rotor 8 is divided into an adsorption zone 9, a desorption zone 10, and a purge zone 11.

  The outside air OA that has been subjected to total heat exchange is cooled by the evaporator 7, the absolute humidity is reduced by condensation, and passes through the adsorption zone 9 of the dehumidifying rotor 8. By this passage, the humidity in the air further decreases, and the air becomes dry air and is supplied to the dry room 6 as supply air SA.

  The dry air that has passed through the adsorption zone 9 of the dehumidification rotor 8 cools the dehumidification rotor 8 by passing through the purge zone 11 of the dehumidification rotor 8, and the temperature of the air that has passed through increases. The air whose temperature has been increased is further increased by the heater 12 and enters the desorption zone 10 of the dehumidifying rotor 8. The air leaving the desorption zone 10 is released into the atmosphere by the blower 13. A part of the air exiting the blower 13 is branched and mixed with the air exiting the purge zone 11 via the air volume control valve 14 and enters the heater 12. Reference numeral 15 denotes a valve which establishes a communication state and a closed state between the blower 4 and the blower 5.

  The dehumidifying air-conditioning apparatus of the present invention has the above configuration, and the operation thereof will be described below together with the air condition of each part. First, the normal operation state will be described.

  The air (1) exiting the blower 4 is outside air, and the air conditions are as shown in Table 1 (1): dry bulb temperature 38.0 degrees, dew point temperature 30.5, absolute humidity 27.6 g / Kg, Relative humidity is 65 percent. When this air is totally heat-exchanged with the return air RA (14) from the dry room 6, as shown in Table 1 (2), the dry bulb temperature is 25.5 degrees, the dew point temperature is 13.8, the absolute humidity is 9.738 g / Kg, air with a relative humidity of 47.94 percent. That is, the outside air is reduced from the absolute humidity of 27.6 g / Kg to 9.738 g / Kg by total heat exchange with the air discarded from the dry room 6.

  Even if the air discarded from the dry room 6 contains a fluorine-based gas, the air subjected to the total heat exchange is outside air and does not contain a fluorine-based gas.

  This air (2) is cooled by the evaporator 7 to become air (3). With this cooling, the air (2) is cooled to a dry bulb temperature of 7 degrees Celsius and dewed to dehumidify, so the air (3) has a dew point temperature of 6.1 degrees. Next, the air (3) is adsorbed with moisture in the adsorption zone 9 of the dehumidifying rotor 1, and the temperature rises due to adsorption heat to a dry bulb temperature of 23.0 degrees, and the dew point temperature is dried to -64.7 degrees. It will be in the state.

  This dried air (4) is branched into air (5) and air (6). Air (5) is sent to the purge zone 11 of the dehumidification rotor 1, and air (6) is sent to the dry room 6 as supply air SA. That is, dry air having a dew point temperature of −64.7 degrees is supplied to the dry room 6. And this supply air SA is the air by which the external air was processed, and is fresh air. The air sent to the adsorption zone 9 and the purge zone 11 of the dehumidifying rotor 1 is also fresh air and does not adversely affect the moisture adsorbent such as silica gel and zeolite.

  The air (7) leaving the purge zone 11 exchanges heat in the purge zone 11, and the dry bulb temperature rises to 80.0 degrees. Further, the purge zone 11 is influenced by the desorption zone 10 and gives some moisture to the air (7) passing through the purge zone 11, and the dew point temperature rises to -51.7 degrees.

  The air (7) leaving the purge zone 11 is mixed with the air (12) leaving the desorption zone 10 and passing through the air volume control valve 14 to become air (8), which is heated by the heater 12. The air (8) before entering the heater 12 has a dry bulb temperature of 78.5 degrees, which is slightly lower than the air exiting the purge zone 11, but the amount of air can be secured. Further, since the air (8) is mixed with the air leaving the desorption zone 10, the dew point temperature is increased to 21.5 degrees.

  The air (9) heated by the heater 12 has a dry bulb temperature rising to 160.0, which reduces the relative humidity to 0.406%. The adsorption-type dehumidifier is dehumidified by the difference between the relative humidity of 95% of the air to be treated (3) and the relative humidity of 0.406% of the air (9) used for desorption, and has exited the heater. Since the relative humidity of the air (9) is extremely low, it is effectively dehumidified.

  The air (10) leaving the desorption zone 10 has desorbed the moisture adsorbed by the dehumidifying rotor 1, so that the humidity increases and the desorption heat is deprived and the temperature decreases to a dew point temperature of 35.10 degrees. The dry bulb temperature becomes 73.5 degrees. The air (10) is pressurized by the blower 13 and becomes air (11) having a dry bulb temperature of 76.5 degrees. This air (11) is branched into two, and becomes air release air (12) and air (12) that has passed through the air volume control valve 14.

  In the dry room 6, for example, a lithium battery is manufactured, and the manufacturing line becomes a humidity load. Also, fluorine gas is generated from the production line. When a toilet or the like is present in the dry room 6, local exhaust is performed from there. The return air RA from the dry room 6 passes through the zone B3 of the total heat exchange rotor 1 as air (14), and exchanges sensible heat and latent heat with the air (1). By this total heat exchange, the air (15) that has passed through the zone B3 has a dry bulb temperature of 31.2 degrees and a dew point temperature of 19.8 degrees.

This air (15) contains fluorine-based gas, but this fluorine-based gas is released to the atmosphere and does not enter the dehumidifying rotor 8. For this reason, the dehumidifying rotor 8 is not damaged by the fluorine-based gas.

  Although the above description is in the normal operation state, the operation in the operation start state from the initial operation start state or the hibernation state of the lithium battery factory will be described next. In the initial operation start state or the operation start state from the hibernation state of the lithium battery factory, it is necessary to start production of the lithium battery after the humidity in the dry room 6 is sufficiently lowered.

  When the dry room 6 is in the initial state, the air condition is almost the same as the condition of the outside air, and in order to change the humidity to a dew point of −40 degrees, air at −60 degrees is at least several tens of hours or It is necessary to keep running for several days. This is the time required for the moisture to completely drain from the floor, walls and ceiling of the dry room, and the equipment installed in the dry room must also be completely dried. is necessary.

  During the drying period, production of the lithium battery cannot be started, so that hydrogen fluoride and phosphoric acid gas are not generated in the dry room. In this case, it is not necessary to consider damage to the dehumidifying rotor 8. Therefore, in the operation start state, it is necessary to make the dry room 9 dry earlier without considering such damage due to gas.

  For this reason, when the dew point temperature of the air discharged from the blower 5 is lower than that of the outside air, the valve 15 is opened so that the air discharged from the blower 5 is returned to the suction side of the blower 4. As a result, the load of dehumidification by the dehumidification rotor 8 is reduced, and the inside of the dry room 9 can be brought to a desired air condition in a shorter time.

  The embodiment shown in FIG. 2 has a reverse purge direction compared to the embodiment shown in FIG. A duplicate description of the configuration common to the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. 2 is avoided.

  In the second embodiment, the air (3) exiting the evaporator 7 is branched into two, one of which is sent to the adsorption zone 9 of the dehumidifying rotor 8 and the other is sent to the purge zone 11 of the dehumidifying rotor 8. To send. The air (7) leaving the purge zone 11 is mixed with the air (12) that has passed through the air volume control valve 14 and enters the heater 12 as air (8). That is, the direction of the air flowing through the purge zone 11 is reversed compared to that in the first embodiment.

  In the first embodiment, the direction of the air flowing in the adsorption zone 9 is opposite to the direction of the air flowing in the purge zone 11, and the purge effect is high. high. However, since the air flow is complicated in the first embodiment, the manufacturing cost is higher than that in the second embodiment.

Therefore, whether to adopt the first embodiment or the second embodiment can be determined depending on whether energy saving is prioritized or cost is prioritized.

  In the case of Example 2, as in the case of Example 1 above, when the condition of the air discharged from the blower 5 is lower than the outside air, the valve 15 is opened and the air is discharged from the blower 5. The air is returned to the suction side of the blower 4. As a result, the load of dehumidification by the dehumidification rotor 8 is reduced, and the inside of the dry room 9 can be brought to a desired air condition in a shorter time.

  In Example 1 and Example 2 described above, an example in which an ion exchange resin is used as a moisture adsorbent as a non-silica total heat exchange rotor has been described. However, aluminum as a moisture adsorbent that is not damaged by a fluorine-based gas. There are also oxides. That is, when the surface of the aluminum sheet is oxidized to make the surface rough, the oxidized layer exhibits moisture adsorption. In this way, a total heat exchange rotor can be obtained.

  Moreover, it is also possible to use activated carbon for a moisture adsorbent as a non-silica total heat exchange rotor. Activated carbon is not damaged by the fluorine-based gas. In this case, the activated carbon powder is used by bonding to an aluminum sheet.

  Alternatively, the total heat exchange rotor may be made of flame retardant paper, and a deliquescent solution such as lithium chloride or potassium chloride may be soaked therein. In short, any rotary total heat exchange rotor using a non-silica reversible moisture adsorbent may be used.

  Dehumidification with a dehumidification rotor using silica-based moisture adsorbents such as silica gel and zeolite, even in situations where extremely low dew point air is required, such as in lithium battery manufacturing plants, and where fluorine-based gas is generated from the air Applicable to air conditioners.

1 Total heat exchange rotor 2 Zone A
3 Zone B
4 Blower 5 Blower 6 Dry Room 7 Evaporator 8 Dehumidification Rotor 9 Adsorption Zone 10 Desorption Zone 11 Purge Zone 12 Heater 13 Blower 14 Air Volume Control Valve 15 Valve

Claims (1)

A total heat exchange rotor that performs total heat exchange between return air from the dry room to which dry air is supplied and outside air is provided, and the total heat exchange rotor uses a non-silica moisture adsorbent, A dehumidification rotor having an adsorption zone, a desorption zone, and a purge zone is provided, the outside air that has passed through the total heat exchange rotor is cooled by a cooler, passed through the adsorption zone, and dry air that has passed through the adsorption zone is used as supply air Supplying dry air to the purge zone and allowing the air to pass through the purge zone to flow in the opposite direction to the air passing through the adsorption zone and heating the air that has passed through the purge zone remains with the heater is provided, through the air heated by the heater to the desorbing zone, providing a blower that outside air releasing air leaving the desorption zone The mixed with air exiting the purge zone portion of air exiting said blower to allow adjusting the mixing ratio through the air-flow control valve is bifurcated to send to the heater, a fluorine-based gas and / or phosphorus A dehumidifying air conditioner that can be used even in an atmosphere in which an acid-based gas is generated.

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