JP6298366B2 - Adsorption type dehumidifier capable of controlling carbon dioxide concentration - Google Patents

Description

A glove box is an experiment where the humidity inside the box is kept extremely low, a hand is inserted through a rubber glove (glove) sealed from the outside of the box, and a dry environment inside the box is used. Is to do. The present invention relates to a dehumidifier capable of controlling the carbon dioxide concentration of supplied air to be low in a dry room such as a glove box under a low dew point environment.

When dehumidifying the air in a specific box, dehumidification by condensation using a refrigerator reduces energy consumption, but it is difficult to reduce the humidity of the air in the box to a negative dew point. It was.

That is, in recent years, development and improvement of lithium ion batteries and lithium ion capacitors have been intensified. Lithium compounds easily adsorb moisture in the air and deteriorate the performance of batteries and capacitors. Therefore, in experiments accompanying these developments, air with extremely low dew point or nitrogen vaporized from liquid nitrogen is used. It is necessary to conduct the experiment in a purged box. In the case of using liquid nitrogen, it is necessary to prepare liquid nitrogen before the experiment. Since the liquid nitrogen is continuously consumed during the experiment, there is a problem that the cost is increased.

In addition, organic EL elements used in organic EL display devices, which are expected as next-generation flat panel displays to replace liquid crystal display devices, are promising for use as solid light-emitting, inexpensive large-area full-color display elements and writing light source arrays. Active research and development is underway. However, organic substances such as organic light-emitting materials used in organic EL elements, electrodes, and the like are weak against moisture and performance and characteristics deteriorate rapidly. Therefore, it is necessary to conduct experiments in a box in which air is purged with air having a very low dew point or nitrogen obtained by vaporizing liquid nitrogen in the experiments accompanying these developments.

Furthermore, in the case of a lithium ion battery, if carbon dioxide is present in the atmosphere, there is a problem that the performance deteriorates as described in Patent Document 1. What is disclosed in this Patent Document 1 is to remove the influence of carbon dioxide in the manufacturing process of an electrode of a lithium ion battery, and air is bubbled into a sodium hydroxide solution as a means for removing carbon dioxide. . However, in the process of completing the lithium ion battery, dry air is required, and bubbling in the solution as a means for removing carbon dioxide causes a problem because the humidity of the air increases.

Moreover, the amine-type thing disclosed by patent document 2 as a carbon dioxide absorber is also what makes a solution absorb a carbon dioxide, and there exists a problem that air is humidified by use.

In addition, what is disclosed in Patent Document 3 is a technology that can accurately control the dew point in the glove box and reduce the carbon dioxide concentration, but uses a carbon dioxide adsorbent such as sodium hydroxide, If the carbon dioxide adsorption capacity declined, it was necessary to replace it with a new carbon dioxide adsorbent.

JP 09-320598 A Japanese Patent Laid-Open No. 06-343858 JP 2014-97437 A

As described above, those disclosed in Patent Document 1 and Patent Document 2 have a problem that the humidity of the air increases in the process of carbon dioxide adsorption or absorption. It is difficult to employ a device that supplies dry air having a dew point of minus 10 degrees to minus 80 degrees as in the present invention. Moreover, what was disclosed by patent document 3 needed to be replaced | exchanged for a new thing, if the adsorption capacity of the carbon dioxide adsorbent used falls.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a dehumidifier capable of reducing the concentration of carbon dioxide contained in dry air and controlling the concentration of carbon dioxide.

The present invention has a precooler that cools the outside air, passes the air cooled and dehumidified by the precooler to the moisture and the adsorption zone of the carbon dioxide adsorption rotor, and thereby supplies the dry air having a low dew point into the room, The most important feature is that the humidity and the rotational speed of the carbon dioxide adsorption rotor are controlled by the carbon dioxide concentration of the supplied air.

The dehumidifier of the present invention uses a humidity and carbon dioxide adsorption rotor to lower the dew point temperature in the drying chamber such as a glove box, and then measures the carbon dioxide concentration of the supply air into the drying chamber. By controlling the rotation speed of the carbon dioxide adsorption rotor, the carbon dioxide concentration in the drying chamber can be accurately controlled in a relatively short time.

In addition, the carbon dioxide concentration can be controlled at a constant dew point temperature by controlling the humidity and the rotation speed of the carbon dioxide adsorption rotor within a range that does not affect the dew point temperature.

FIG. 1 is a flowchart showing an embodiment of the dehumidifier of the present invention. FIG. 2 is a graph showing the relationship between the rotation speed of the adsorption rotor used in the present invention, the concentration at the treatment outlet carbon dioxide, and the treatment outlet dew point temperature. FIG. 3 is a graph showing changes over time in the supply air dew point and the supply carbon dioxide concentration when this embodiment is used.

The present invention supplies moisture and dry air having a low dew point after passing through the adsorption zone of the carbon dioxide adsorption rotor into the room, and controls the rotation speed of the moisture and the carbon dioxide adsorption rotor by the carbon dioxide concentration of the supply air. By doing so, the purpose of providing a dehumidifier capable of controlling the drying chamber to a constant dew point and controlling the carbon dioxide concentration in the drying chamber was realized.

Hereinafter, it demonstrates along FIG. 1 which shows the Example of this invention. The flow rate of the outside air OA is adjusted by the valve 1, and dust is removed by the first air filter 2. The temperature of the outside air is measured by the temperature sensor 3, cooled by the first precooler 4, and dehumidified by condensation. The temperature of the air exiting the first precooler 4 is measured by the temperature sensor 5. This air flow is created by the fan 6.

Reference numeral 7 denotes an adsorption rotor capable of adsorbing moisture and carbon dioxide, and is a known one in which silica, zeolite, ion exchange resin and the like adsorbing moisture and carbon dioxide are supported on a honeycomb rotor. The adsorption rotor 7 is divided into an adsorption zone 8, a purge zone 9, and a regeneration zone 10. The suction rotor 7 is rotationally driven and rotational speed controlled by a geared motor 11. The dry air that has passed through the adsorption zone 8 is heated to a desired temperature by an after heater 12. Contamination is removed from the air whose temperature has been raised by the after heater 12 by the second air filter 13. That is, the adsorbent that has fallen off from the surface of the adsorption rotor 7 is removed.

The air that has passed through the second air filter 13 is branched into two paths, an external supply path 14 and a return path 15. A valve 16 is provided in the return path 15, and thereby the return air volume is set. The return path 15 is provided with a second precooler 17 that lowers the temperature of the air to a predetermined temperature and promotes moisture adsorption in the adsorption zone 8. A temperature sensor 18 is provided on the outlet side of the second precooler 17, whereby the outlet temperature of the second precooler 17 is controlled. Air exiting the second precooler 17 is sucked into the fan 6 and sent to the adsorption zone 8. That is, the cooled outside air and the air returned through the return path 15 are mixed and sent to the adsorption zone 8.

The air that has passed through the second air filter 13 and is sent to the external supply path 14 is supplied into the drying chamber after the carbon dioxide concentration sensor 20 measures the carbon dioxide concentration. The rotation speed of the adsorption rotor 7 by the geared motor 11 is controlled according to the detection data of the carbon dioxide concentration sensor 20. That is, the amount of carbon dioxide adsorbed by the adsorption rotor 7 is controlled according to the detection data of the carbon dioxide concentration sensor 20, and the supply air SA having a desired carbon dioxide concentration can be sent to an external drying chamber (not shown).

The air exiting the purge zone 9 passes through the valve 21, is heated by the regeneration heater 22, and is sent to the regeneration zone 10. The temperature of the air before and after passing through the regeneration zone 10 is measured by the temperature sensors 23 and 24. If the difference between the measured values of the temperature sensors 23 and 24 is greater than or equal to a predetermined value, it can be seen that the reproduction zone 10 is sufficiently regenerated. The air that has passed through the regeneration zone 10 is discharged to the outside by the fan 25 as exhaust EA.

The first embodiment of the present invention is configured as described above, and the operation will be described below. First, the valve 1 is opened to operate the first precooler 4, the fan 6, the geared motor 11, the second precooler 17, the regenerative heater 22, and the fan 25. Thus, the outside air OA is sucked by the fan 6, dust is removed by the first air filter 2, the temperature is measured by the temperature sensor 3, and the first precooler 4 is cooled. With this cooling, the dew point decreases to the temperature of the first precooler 4. That is, it is dehumidified by condensation.

The temperature of the dehumidified and lowered humidity is measured by the temperature sensor 5 and passes through the adsorption zone 8 of the adsorption rotor 7 by the fan 6, and the humidity is further reduced by adsorption. At this time, the suction rotor 7 is rotated by the geared motor 11. Depending on the temperature measured by the temperature sensor 5, the temperature of the air leaving the adsorption zone 8 rises by the after heater 12 if necessary. The air that has passed through the after-heater 12 is separated into the external supply path 14 and the return path 15 by removing the adsorbent that has fallen off from the adsorption rotor 7 by the second air filter 13.

Here, after cooling with the first precooler 4, heating with the after-heater 12 seems to be useless, but the first precooler 4 is not only cooled but also dehumidified by condensation as described above. This is because in order to secure the dehumidification amount and to secure the adsorption amount in the adsorption zone 8 by lowering the temperature, it is required to cool below the temperature desired for the externally supplied air.

The air branched into the return path 15 has its return air amount determined by the valve 16 and cooled by the second precooler 17, and its temperature is measured by the temperature sensor 18 and mixed with the outside air OA passing through the first precooler 4. Then, it passes through the suction zone 8 of the suction rotor 7 again. By this circulation, the dew point of the supply air SA can be lowered to minus 70 degrees. In addition, you may install the return path 15 so that the air immediately after passing the adsorption | suction zone 8 in front of the after heater 12 may circulate.

The air exiting the fan 6 is branched to the purge zone 9 where heat is recovered and the purge amount is adjusted by the valve 21, heated by the regeneration heater 22, and sent to the regeneration zone 10. The temperature before and after the air sent to the regeneration zone 10 is measured by the temperature sensor 23 and the temperature sensor 24. If the temperature difference is less than or equal to a predetermined value, it can be seen that the amount of regeneration in the regeneration zone 10 is not secured. In this case, the regeneration amount is secured by raising the temperature of the regeneration heater 22. The humid air leaving the regeneration zone 10 is discharged to the outside as exhaust EA by the fan 25.

The air in the external supply path 14 is supplied to the drying chamber after the carbon dioxide concentration is measured by the carbon dioxide concentration sensor 20. The geared motor 11 is controlled by PID control or the like to control the rotation speed of the adsorption rotor 7 so that the measured carbon dioxide concentration becomes a desired carbon dioxide concentration. FIG. 2 is a graph showing the relationship between the treatment outlet carbon dioxide concentration and the treatment outlet dew point with respect to the rotation speed of the adsorption rotor used in the present invention. When the rotation speed of the adsorption rotor is around 7-8 rph, the carbon dioxide concentration at the treatment outlet is the lowest at about 15 ppm. Further, as the rotation speed of the adsorption rotor is decreased, the carbon dioxide adsorption amount of the adsorption rotor decreases, so that the carbon dioxide concentration at the treatment outlet increases and increases to about 100 ppm at around 3.5 rph. Therefore, the carbon dioxide concentration at the treatment outlet can be controlled to a desired concentration by changing the rotation speed of the adsorption rotor around 3 to 8 rph. Since the processing outlet dew point is constant in the rotation speed range of the adsorption rotor, the dew point does not change even if the rotation speed is changed.

FIG. 3 shows a graph of the change over time of the supply air dew point and the supply carbon dioxide concentration when an adsorption rotor having an outer diameter of 250 mm and a width of 450 mm is used in the present invention. In a state without carbon dioxide concentration control, when setting from about 15 ppm to carbon dioxide concentration control 30 ppm, the dew point temperature was minus 50 degrees and the carbon dioxide concentration was 30 ppm ± 3 ppm in about 50 minutes. Thereafter, when the setting was changed to carbon dioxide concentration control of 80 ppm, the dew point temperature was minus 50 degrees and the carbon dioxide concentration was 80 ppm ± 10 ppm in about 30 minutes. Furthermore, if the dew point temperature was changed to minus 30 degrees and then the carbon dioxide concentration control was changed to 30 ppm, the dew point temperature was minus 30 degrees and the carbon dioxide concentration was 30 ppm ± 3 ppm in about 30 minutes.

The present invention can provide a dehumidifier capable of controlling the carbon dioxide concentration in the drying chamber at 20 to 80 ppm by changing the rotation speed of the adsorption rotor as described above.

DESCRIPTION OF SYMBOLS 1 Valve 2 1st air filter 3 Temperature sensor 4 1st precooler 5 Temperature sensor 6 Fan 7 Dehumidification rotor 8 Adsorption zone 9 Purge zone 10 Regeneration zone 11 Geared motor 12 After heater 13 Second air filter 14 External supply path 15 Return path 16 Valve 17 Second precooler 18 Temperature sensor 19 Valve 20 Carbon dioxide concentration sensor 21 Valve 22 Regenerative heater 23 Temperature sensor 24 Temperature sensor 25 Fan

Claims (3)

A first precooler that cools and dehumidifies the outside air, an adsorption rotor that further dehumidifies the air cooled by the first precooler, a return path that circulates a portion of the air dehumidified by the adsorption rotor, and air that is dehumidified by the adsorption rotor An external supply path for supplying a part of the gas to the outside, and a carbon dioxide concentration sensor for measuring the carbon dioxide concentration of the air in the external supply path, and the rotation speed of the adsorption rotor according to the output of the carbon dioxide concentration sensor An adsorption type dehumidifying device, characterized in that a control means for controlling the pressure is provided. The adsorption dehumidifier according to claim 1, wherein PID control is used for the control means. The adsorption type dehumidifier according to claim 1, wherein the adsorption rotor has a carbon dioxide adsorption amount that changes within a range of rotor rotation speed with a constant processing outlet dew point.

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