JP2009291732A - Pressure swing adsorption (psa) type dehumidifying apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To economically and simply produce air with a low dew point of -100°C or lower dew point. <P>SOLUTION: The PSA type dehumidification apparatus 1 is for obtaining air with low dew point by pressure swing adsorption by alternately carrying out a treatment step of passing air to be treated to adsorption containers 10a, 10b containing an adsorption material and a regeneration step of passing regeneration air and includes a heating mechanism 35 for supplying heated air at a high temperature to the adsorption containers 10a, 10b and temperature sensors 50a, 50b for measuring temperature of the adsorption material at a position near the outlet side from the center of an inlet and an outlet and between the inlet and the outlet for the air to be treated in the adsorption containers 10a, 10b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a PSA type dehumidification technique for obtaining low dew point air by pressure swing adsorption.

  In the semiconductor manufacturing field or the like, for example, low dew point air having a dew point temperature of −100 ° C. or lower is used. In order to obtain this low dew point air, a PTSA type dehumidification method or a PSA type dehumidification method is used. The PTSA type dehumidification method alternately performs a treatment process in which treated air is pressurized and passed through an adsorption container containing an adsorbent, and a regeneration process in which high-temperature regenerated air is passed through the adsorption container under normal pressure or reduced pressure. / This is a method of repeating desorption (regeneration). According to this PTSA type dehumidification method, low dew point air having a high dehumidification rate such as a dew point temperature of −100 ° C. or less can be obtained. However, the PTSA type dehumidification technology, (1) it is necessary to permanently install a large heating mechanism in order to produce high temperature regeneration air, (2) it is necessary to make the parts of the passage of regeneration air heat resistant (3) When the adsorption / regeneration cycle is alternately performed with two adsorption containers, the adsorption process is continued in the other adsorption container while the adsorbent is heated and cooled in one adsorption container. In order to lengthen the adsorption time, the amount of the adsorbent used is increased, and the size of the adsorption container must be increased. For this reason, according to the PTSA type dehumidification method, the apparatus becomes larger than the PSA type dehumidification method, and the apparatus cost increases.

  On the other hand, the PSA dehumidification method is a method of regenerating the adsorbent under normal pressure or reduced pressure without heating during regeneration. The difference between the PTSA type dehumidifying method and the PSA type dehumidifying method lies in the presence or absence of heating during regeneration. According to the PSA type dehumidifying method, no heating operation is required, and thus the apparatus can be reduced in size and cost. Further, since the adsorbent is not heated during regeneration, deterioration of the adsorbent can be reduced as compared with the PTSA type dehumidifying method. However, the PSA type dehumidification method has lower water removal performance than the PTSA type dehumidification method. In particular, when the operation is resumed after the dehumidification operation has been stopped for a long period of time or when the operation is started after replacement of the adsorbent, the water removal performance is reduced. Therefore, it has been difficult to produce low dew point air having a dew point temperature of −100 ° C. or lower. Therefore, in order to improve the dehumidifying performance of the PSA dehumidifying method, a method has been proposed in which high-temperature heated air is supplied to the adsorbent at an appropriate timing to discharge moisture remaining in the adsorbent (for example, Patent Document 1).

JP 11-179136 A

  However, in the method disclosed in Patent Document 1, heated air is supplied until moisture is completely discharged from the adsorbent in the adsorption container. For this reason, it took a long time to discharge moisture, and during that time, dehumidifying operation was not possible. In addition, since it has been necessary to continue supplying high-temperature heated air into the adsorption container for a long time, it has been necessary to excessively improve the heat resistance of the adsorption container and piping. Therefore, according to the method of Patent Document 1, there is a problem that it is impossible to reduce the size and cost of the apparatus, which is an advantage of the PSA dehumidification method.

  An object of the present invention is to produce low dew point air having a dew point temperature of −100 ° C. or less easily and inexpensively.

  According to the present invention, a PSA-type dehumidifying device that alternately performs a treatment step of passing treatment air through an adsorption container containing an adsorbent and a regeneration step of passing regeneration air to obtain low dew point air by pressure swing adsorption, A heating mechanism for supplying high-temperature heated air into the adsorption container, and the temperature of the adsorbent in the adsorption container between the inlet and outlet of the processing air and from the center of the inlet and outlet to the outlet side. A PSA type dehumidifying device provided with a temperature sensor to be measured is provided. Note that a plurality of the adsorption containers may be provided, and a common heating mechanism that supplies heated air to the adsorption containers may be provided. Further, the heating mechanism may include a dehumidifier and a heater for making heated air from the processing air.

  In addition, according to the present invention, there is provided a PSA type dehumidification method in which a treatment step of passing treatment air and a regeneration step of passing regeneration air are alternately performed in an adsorption container containing an adsorbent to obtain low dew point air by pressure swing adsorption. A heating step of supplying high-temperature heated air into the adsorption vessel, and the heating step is stopped when the temperature of a part of the adsorbent in the adsorption vessel reaches a predetermined temperature. A dehumidification method is provided. Note that a plurality of the adsorption containers may be provided, and heated air may be supplied from a common heating mechanism to each adsorption container. Further, the heating step may be performed when the dehumidifying operation is restarted or when the operation is started after exchanging the adsorbent.

  According to the present invention, when the moisture remaining in the adsorbent is discharged, only a part of the adsorbent in the adsorption container needs to be heated to a predetermined temperature, and it is not necessary to heat the entire adsorbent in the container. . For this reason, moisture can be discharged in a short time, and the operation stop time of the dehumidifying operation can be shortened. As a result, low dew point air having a dew point temperature of −100 ° C. or lower can be made inexpensively and easily.

  If heated air is supplied to a plurality of adsorption containers from a common heating mechanism, there is no need to provide a heating mechanism for each adsorption container, the apparatus is simple, and space can be saved. In this case, the heating mechanism does not need to be permanently installed, and may be attached only when moisture remaining in the adsorbent is discharged. Also, when the dehumidifying operation is restarted or when the operation after the replacement of the adsorbent is started, a heating process for discharging moisture from the adsorbent is performed, particularly when the operation is resumed after the dehumidifying operation has been stopped for a long period of time, It is possible to avoid a decrease in water removal performance at the start of operation after replacement.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1-3 is explanatory drawing of the PSA type dehumidification apparatus 1 concerning embodiment of this invention. FIG. 1 shows a state in which a treatment process is performed in one adsorption container 10a and a regeneration process is performed in the other adsorption container 10b. FIG. 2 shows a state in which the regeneration process is performed in one adsorption container 10a and the treatment process is performed in the other adsorption container 10b. FIG. 3 shows a state in which the heating process is performed in one adsorption container 10a and the other adsorption container 10b. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  The PSA dehumidifier 1 includes a pair of adsorption containers 10a and 10b. Each of the adsorption containers 10a and 10b has a hollow cylindrical shape, and an adsorbent such as zeolite is accommodated in each of the adsorption containers 10a and 10b.

  A lower pipe 11a is connected to the lower surface of one adsorption container 10a, and a lower pipe 11b is connected to the lower surface of the other adsorption container 10b. A processing air supply pipe 12 is connected to the lower pipes 11 a and 11 b via a three-way valve 13. The three-way valve 13 can be selectively switched between a state in which one lower pipe 11a and the air supply pipe 12 are connected and a state in which the other lower pipe 11b and the air supply pipe 12 are connected. By switching the three-way valve 13, as shown in FIG. 1, the process air is circulated upward from the supply pipe 12 to the one adsorption vessel 10a through the lower pipe 11a, and as shown in FIG. It is possible to selectively switch to a state in which the processing air is circulated upward from the air pipe 12 to the other adsorption container 10b via the lower pipe 11b. In the illustrated example, the lower surfaces of the adsorption containers 10a and 10b to which the lower pipes 11a and 11b are connected are inlets for the processing air.

  A bypass pipe 15 is connected between one lower pipe 11a and the other lower pipe 11b. A regenerative air exhaust pipe 16 to be described later is connected to the bypass pipe 15 via a three-way valve 17. The three-way valve 17 has a state in which the other lower pipe 11b and the exhaust pipe 16 are connected via the bypass pipe 15 as shown in FIG. 1, and one side via the bypass pipe 15 as shown in FIG. The lower pipe 11a and the exhaust pipe 16 can be selectively switched.

  The upper pipe 20a is connected to the upper surface of one adsorption container 10a, and the upper pipe 20b is connected to the upper surface of the other adsorption container 10b. A low dew point air delivery pipe 21 is connected to the upper pipes 20a and 20b. A check valve 22 is mounted on each of the upper pipes 20a and 20b. In the illustrated example, the upper surfaces of the adsorption containers 10a and 10b to which the upper pipes 20a and 20b are connected are outlets for the processing air.

  A bypass pipe 25 is connected between one upper pipe 20a and the other upper pipe 20b. An orifice 26 is provided in the bypass pipe 25.

  Between the upper part of one adsorption container 10a and the upper part of the other adsorption container 10b, the heating air supply piping 30 of the heated air mentioned later is connected. A heated air supply pipe 32 is connected to the heated air supply pipe 30 via a connection port 31 that can be freely opened and closed. A branch pipe 34 is connected to the above-described air supply pipe 12 via a connection port 33 that can be freely opened and closed.

  A heating mechanism 35 for supplying high-temperature heated air is provided between the introduction pipe 32 and the branch pipe 34. The heating mechanism 35 has a configuration in which a dehumidifier 37 and a heater 38 are mounted on a movable traveling carriage 36. A pipe 40 having an open / close valve 39 is connected between the dehumidifier 37 and the heater 38. The heating mechanism 35 includes a controller 41 that controls the operation of the dehumidifier 37 and the heater 38.

  The connection ports 31 and 33 are both removable. By removing these connection ports 31 and 33, the heating mechanism 35 can be disconnected from the PSA dehumidifier 1. The separated heating mechanism 35 can be easily moved to a desired position by the traveling carriage 36.

  An openable and closable exhaust port 45 is provided at the lower part of one adsorption container 10a and the lower part of the other adsorption container 10b.

  One adsorption container 10a has a temperature sensor such as a thermocouple for measuring the temperature of the adsorbent filled in the adsorption container 10a at a height between the connection position of the heating and air supply pipe 30 and the connection position of the exhaust port 45. 50a is provided. The temperature sensor 50a is located between the inlet (the lower surface of the adsorption container 10a) and the outlet (the upper surface of the adsorption container 10a) of the processing air, and is located on the outlet side from the center of the inlet and the outlet (the central height of the adsorption container 10a). Is arranged. For this reason, the temperature sensor 50a can measure the temperature of the adsorbent at the upper position from the center of the adsorption container 10a. Similarly, the other adsorption container 10b has a heat transfer for measuring the temperature of the adsorbent filled in the adsorption container 10b at a height between the connection position of the heating / air supply pipe 30 and the connection position of the exhaust port 45. A comparable temperature sensor 50b is provided. The temperature sensor 50b is located between the inlet of the processing air (lower surface of the adsorption container 10b) and the outlet (upper surface of the adsorption container 10b), and is located on the outlet side from the center of the inlet and outlet (center height of the adsorption container 10b). Is arranged. For this reason, the temperature sensor 50b can measure the temperature of the adsorbent at the upper position from the center of the adsorption container 10b.

  The temperatures measured by these temperature sensors 50 a and 50 b are input to the control unit 41 of the heating mechanism 35. The control unit 41 of the heating mechanism 35 controls the operation of the dehumidifier 37 and the heater 38 based on the temperature thus input.

  Now, in the PSA type dehumidifier 1 configured as described above, first, when a treatment process is performed in one adsorption container 10a and a regeneration process is performed in the other adsorption container 10b, as shown in FIG. The three-way valve 13 is switched to a state in which one lower pipe 11a and the air supply pipe 12 are connected, and the three-way valve 17 is switched to a state in which the other lower pipe 11b and the exhaust pipe 16 are connected. Further, the connection ports 31 and 33 are closed. Further, the exhaust ports 45 provided at the lower portions of the adsorption containers 10a and 10b are all closed. Further, neither the dehumidifier 37 nor the heater 38 provided in the heating mechanism 35 is operated.

  And as shown in FIG. 1, process air is distribute | circulated upwards to one adsorption | suction container 10a via the lower piping 11a from the air supply piping 12. As shown in FIG. Thereby, the process process which makes the adsorption material adsorb | suck the water | moisture content and carbon dioxide in process air in the one adsorption | suction container 10a in the pressurized state is performed. Thus, the low dew point air, for example, having a dew point temperature of −100 ° C. or less from which moisture has been removed in the treatment process in the adsorption container 10a, is sent from one upper pipe 20a through the delivery pipe 21 to a desired location.

  A part of the low dew point air that has exited the adsorption container 10a is taken out to the bypass pipe 25 as regenerated air. Thus, the amount of regenerated air (low dew point air) taken out to the bypass pipe 25 is adjusted by the orifice 26. Then, the regenerated air taken out to the bypass pipe 25 is circulated downward in the other adsorption vessel 10b via the other upper pipe 20b. Thereby, in the other adsorption container 10b, a regeneration process for desorbing moisture and carbon dioxide from the adsorbent under normal pressure or reduced pressure is performed. Thus, the regeneration air used in the regeneration process is exhausted to the outside from the exhaust pipe 16 via the bypass pipe 15 via the other lower pipe 11b.

  Further, when the treatment process is continuously performed in one adsorption container 10a as described above, the amount of moisture adsorbed on the adsorbent in one adsorption container 10a gradually increases, and eventually the dew point temperature − Low dew point air of 100 ° C. or lower cannot be obtained. Therefore, before the amount of moisture adsorbed on the adsorbent in one adsorption container 10a reaches the limit, the state is switched to a state in which the treatment process is performed in the other adsorption container 10b.

  That is, as shown in FIG. 2, the three-way valve 13 is switched to a state in which the other lower pipe 11b and the air supply pipe 12 are connected, and the three-way valve 17 is in a state in which the one lower pipe 11a and the exhaust pipe 16 are connected. Switch. Further, the connection ports 31 and 33 are closed. Further, the exhaust ports 45 provided at the lower portions of the adsorption containers 10a and 10b are all closed. Further, neither the dehumidifier 37 nor the heater 38 provided in the heating mechanism 35 is operated.

  And as shown in FIG. 2, process air is distribute | circulated upwards from the supply piping 12 to the other adsorption | suction container 10b via the lower piping 11b. Thereby, the process process which makes the adsorption material adsorb | suck the water | moisture content and carbon dioxide in process air is performed in the other adsorption | suction container 10b in the pressurized state. In this way, for example, low dew point air having a dew point temperature of −100 ° C. or less from which moisture has been removed in the treatment process in the adsorption container 10b is sent from the other upper pipe 20b through the delivery pipe 21 to a desired location.

  Further, a part of the low dew point air that has exited the adsorption container 10b is taken out to the bypass pipe 25 as regenerated air. Thus, the amount of regenerated air (low dew point air) taken out to the bypass pipe 25 is adjusted by the orifice 26. Then, the regenerated air taken out to the bypass pipe 25 is circulated downward in the one adsorption container 10a via the one upper pipe 20a. Thereby, in the one adsorption | suction container 10a, the reproduction | regeneration process which desorb | sucks a water | moisture content and a carbon dioxide from an adsorbent under a normal pressure or pressure reduction is performed. Thus, the regeneration air used in the regeneration process is exhausted to the outside from the exhaust pipe 16 via the bypass pipe 15 via the one lower pipe 11a.

  Thus, as shown in FIG. 1, the treatment process is performed in one adsorption container 10a and the regeneration process is performed in the other adsorption container 10b, and the treatment process is performed in the other adsorption container 10b as shown in FIG. By performing the process and alternately repeating the state of performing the regeneration process in one of the adsorption containers 10a, the low dew point air produced by pressure swing adsorption, for example, having a dew point temperature of −100 ° C. or lower is continuously supplied from the delivery pipe 21. Sent out.

  By the way, the inventors inferred the cause of “the dehumidifying performance has deteriorated immediately after the apparatus is stopped for a long time and restarted”, which is one of the problems to be solved by the present invention, as follows. did. That is, one was assumed to be caused by moisture mixed from the outside and the other by moisture diffusion in the adsorbent in the adsorption containers 10a and 10b. The latter is as shown in FIG. In FIG. 4, (a) shows the moisture distribution at the start of the treatment process. (B) shows the moisture distribution state at the end of the treatment process. Note that (c) shows the moisture distribution state when the operation is restarted after the dehumidification operation has been stopped for a long period of time, or when the operation is started after the replacement of the adsorbent. 4A to 4C, the bottom sides (horizontal axes) of the adsorption containers 10a and 10b indicate the amount of moisture, and the amount of moisture increases to the right. The left vertical side (vertical axis) of the adsorption containers 10a and 10b indicates the height in the adsorption containers 10a and 10b. The graph line x written inside the adsorption containers 10a and 10b indicates the moisture distribution state at each height in the adsorption containers 10a and 10b.

  By the way, in this embodiment, for example, before the low dew point air having a dew point temperature of −100 ° C. or less is not obtained, the processing step is stopped and the regeneration step is started. As a result, as shown in FIG. 4 (a), even if moisture still remains in the adsorbent in the lower portions of the adsorption containers 10a and 10b, almost no moisture remains in the adsorbent in the upper portions of the adsorption containers 10a and 10b. It is returned to the state that is not. In this way, the treatment process is performed in one adsorption container 10a, the regeneration process is performed in the other adsorption container 10b, the treatment process is performed in the other adsorption container 10b, and the regeneration process is performed in one adsorption container 10a. The state to be performed is repeated alternately. Thereby, for example, low dew point air having a dew point temperature of −100 ° C. or lower is continuously sent out from the delivery pipe 21.

  In this embodiment, when restarting the operation to restore the dehumidifying performance of the adsorbent or when starting the operation after exchanging the adsorbent, high-temperature heated air is supplied into the adsorption containers 10a and 10b, A heating process is performed to discharge the water remaining on the substrate.

  That is, when performing a heating process, as shown in FIG. 3, the connection ports 31 and 33 are opened, and all the exhaust ports 45 provided in the lower part of adsorption container 10a, 10b are opened. In addition, both the dehumidifier 37 and the heater 38 provided in the heating mechanism 35 are operated.

  Then, as shown in FIG. 3, the processing air that has flowed into the branch pipe 34 from the air supply pipe 12 is introduced into the heating mechanism 35. In the heating mechanism 35, the processing air is dehumidified by the dehumidifier 37 and heated by the heater 38, thereby creating dry high-temperature heated air. The heated air thus created by the heating mechanism 35 is heated and supplied from the introduction pipe 32. It is supplied to the upper part of the adsorption containers 10a and 10b via the air pipe 30. Then, in the adsorption containers 10a and 10b, the heated air is circulated downward, whereby the moisture remaining in the adsorbent is gradually removed from the upper parts of the adsorption containers 10a and 10b, and the treated containers are processed. Together with the heated air, it is exhausted to the outside through the exhaust port 45 from the lower portions of the adsorption containers 10a and 10b.

  Thus, after the dehumidifying performance of the adsorbent is restored, the treatment process and the regeneration process are sequentially performed again in the adsorption containers 10a and 10b. Thereby, for example, low dew point air having a dew point temperature of −100 ° C. or less created by pressure swing adsorption is continuously sent out from the delivery pipe 21.

  Here, when performing a heating process, operation | movement of the dehumidifier 37 and the heater 38 of the heating mechanism 35 is controlled by the control part 41 as follows. That is, during the heating process, the temperature of the adsorbent in the adsorption containers 10a and 10b is measured by the temperature sensors 50a and 50b. In this case, the temperature sensors 50a and 50b are arranged at positions on the outlet side from the central height of the adsorption containers 10a and 10b. For this reason, in the adsorption containers 10a and 10b, the temperature of the adsorbent is measured by the temperature sensors 50a and 50b at the upper position from the center. In this way, the measured temperature of the adsorbent in the upper portions of the adsorption containers 10 a and 10 b is input to the control unit 41.

  FIG. 5 is an explanatory diagram showing the temperature of the adsorbent at each height in the adsorption containers 10a and 10b. The temperature Th is the temperature of the adsorbent at the top of the adsorption containers 10a and 10b, and the temperature Tm is The temperature and temperature Tl of the adsorbent in the middle part (position from the center to the upper part) in the adsorption containers 10a and 10b are the temperature of the adsorbent in the lowermost part in the adsorption containers 10a and 10b. FIG. 6 is a graph showing temporal changes in the temperatures Th, Tm, and Tl at each height during the heating process. The intermediate temperature Tm is a temperature measured by the temperature sensors 50a and 50b.

  During the heating process, high-temperature heated air supplied from the upper parts of the adsorption containers 10a and 10b is circulated downward in the adsorption containers 10a and 10b and is exhausted from the lower parts of the adsorption containers 10a and 10b. For this reason, as shown in FIG. 6, the temperature of the adsorbent in the adsorption containers 10a and 10b is such that the uppermost temperature Th rises first, then the intermediate temperature Tm rises, and the lowermost temperature Tl. Will rise at the end. The intermediate temperature Tm measured by the temperature sensors 50 a and 50 b is input to the control unit 41.

  Therefore, in the present invention, the heating process is stopped when the temperature Tm of the intermediate portion measured by the temperature sensors 50a and 50b reaches a predetermined temperature. That is, a predetermined target temperature T is set in advance for the intermediate temperature Tm, and the heating process is performed when the temperature Tm measured by the temperature sensors 50a and 50b reaches the temperature T (time t). Stop.

  At time t, as shown in FIG. 6, the temperature gradient in which the uppermost temperature Th is higher than the temperature T, the intermediate temperature Tm is equal to the temperature T, and the lowermost temperature Tl is lower than the temperature T. Will occur. After the heating process is completed, a cooling gas is introduced into the adsorption containers 10a and 10b, the adsorbent in the adsorption containers 10a and 10b is cooled to eliminate the temperature gradient, and then the adsorption process and the regeneration process are restarted.

  Here, FIG. 7 is explanatory drawing which shows the distribution state of the water | moisture content of the adsorption material in adsorption container 10a, 10b by a heating process. In FIG. 7, (a) shows a state before the heating step. (B) has shown the state immediately after performing the heating process according to a prior art. (C) has shown the state immediately after restarting the adsorption | suction process and the reproduction | regeneration process after performing the heating process according to a prior art. (D) has shown the state immediately after performing the heating process according to this invention. (E) has shown the state immediately after restarting the adsorption | suction process and the reproduction | regeneration process after performing the heating process according to this invention. 7A to 7E, the bottom sides (horizontal axes) of the adsorption containers 10a and 10b indicate the amount of moisture, and the amount of moisture increases to the right. The left vertical side (vertical axis) of the adsorption containers 10a and 10b indicates the height in the adsorption containers 10a and 10b. The graph line x written inside the adsorption containers 10a and 10b indicates the moisture distribution state at each height in the adsorption containers 10a and 10b.

  As shown in FIG. 7 (a), in a state before the heating step, moisture is diffused in a uniform distribution throughout the adsorbent, and at any height in the adsorption containers 10a and 10b, It is considered that moisture remains in the adsorbent. Thus, if moisture remains in the adsorbent even in the upper portions of the adsorbing containers 10a and 10b, the dehumidifying performance of the adsorbent is inferior. For example, low dew point air having a dew point temperature of −100 ° C. or lower can be created. Disappear. Therefore, a heating process is performed in which high-temperature heated air is supplied into the adsorption containers 10a and 10b, and moisture remaining in the adsorbent is discharged in the upper portions of the adsorption containers 10a and 10b.

  In the prior art, as shown in FIG. 7B, moisture is completely removed from the adsorption containers 10a and 10b by performing a heating process. In other words, in the prior art, moisture remaining in the adsorbent is exhausted in the entire range in the adsorption containers 10a and 10b, and when the heating process is completed, the upper and lower portions in the adsorption containers 10a and 10b are lowered. Until now, almost no moisture remained.

  Then, when the adsorption process and the regeneration process are restarted after the heating process according to the conventional technique, moisture increases from the lower portions in the adsorption containers 10a and 10b as shown in FIG. In this case, in the upper part in the adsorption containers 10a and 10b, since moisture does not adhere to the adsorbent, the dehumidifying performance is sufficiently exhibited. For this reason, in the adsorption containers 10a and 10b in which the processing steps are performed, moisture and carbon dioxide are adsorbed by the adsorbent when the processing air flowing upward passes through the upper parts of the adsorption containers 10a and 10b. For example, low dew point air having a dew point temperature of −100 ° C. or lower can be created.

  However, when the heating process is performed until the moisture is completely removed from the adsorption containers 10a and 10b as in the prior art, it takes a long time to discharge the moisture, and during that time, the PSA dehumidifier 1 can be dehumidified. Disappear. In addition, since it takes a long time to supply high-temperature heated air into the adsorption containers 10a and 10b, it is necessary to excessively improve the heat resistance of the adsorption containers 10a and 10b and piping.

  Therefore, in the present invention, the heating process is stopped when the temperature Tm measured by the temperature sensors 50a and 50b reaches a predetermined temperature T as shown in FIG. In this case, the temperature T for stopping the heating process is sufficiently removed from the adsorbent in the adsorption containers 10a and 10b, for example, below the position where the temperature sensors 50a and 50b are installed. Although not performed, an index value may be set above the position where the temperature sensors 50a and 50b are installed so that moisture can be sufficiently removed from the adsorbent.

  Thus, by stopping the heating process when the temperature Tm measured by the temperature sensors 50a and 50b reaches the predetermined temperature T, moisture is completely removed from the adsorption containers 10a and 10b as in the prior art. It is not necessary to perform a heating process until it is made, and when the moisture is removed from the adsorbent in the upper portions of the adsorption containers 10a and 10b, the heating process can be completed.

  Even when the adsorption step and the regeneration step are restarted after the heating step according to the present invention, moisture increases from the lower portions in the adsorption containers 10a and 10b as shown in FIG. Compared to the prior art (c), the lower part in the adsorption containers 10a, 10b has a wider range (height) of moisture, but the upper part in the adsorption containers 10a, 10b has no water adhering to the adsorbent. Therefore, it is in a state where the dehumidifying performance can be sufficiently exhibited. For this reason, in the adsorption containers 10a and 10b in which the processing steps are performed, moisture and carbon dioxide are adsorbed by the adsorbent when the processing air flowing upward passes through the upper parts of the adsorption containers 10a and 10b. For example, low dew point air having a dew point temperature of −100 ° C. or lower can be created.

  Therefore, according to the present invention, the heating process can be completed in a short time, and the operation stop time of the dehumidifying operation can be shortened. As a result, low dew point air having a dew point temperature of −100 ° C. or lower can be made inexpensively and easily. As described above, also when the adsorbent in the adsorption containers 10a and 10b is cooled after the heating process is completed, the temperature Tm measured by the temperature sensors 50a and 50b can be used as a guide.

  As mentioned above, although an example of preferable embodiment of this invention was demonstrated, this invention is not limited to the form of illustration. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the ideas described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs. For example, as shown in FIG. 8, the adsorption containers 10 a and 10 b removed from the PSA dehumidifier 1 are subjected to a heating process using another heating mechanism 35 ′, and then returned to the PSA dehumidifier 1. You may resume driving.

  As described above with reference to FIGS. 1 to 3, if the heating mechanism 35 can be separated from the PSA dehumidifier 1, the advantages of the PSA dehumidifier such as low cost and small size can be easily utilized. The heating process does not need to be performed for each cycle, and the heating process may be performed by connecting the heating mechanism 35 to the PSA dehumidifier 1 only when necessary. The apparatus can be simplified by providing the heating mechanism 35 separately from the main body (PSA type dehumidifying apparatus 1) without providing the heating mechanism 35 permanently.

  Although the example which has a pair of adsorption | suction container 10a, 10b previously demonstrated in FIGS. 1-3, the number of adsorption containers is not restricted to two, Three or more may be sufficient. The PSA type dehumidifier 1 shown in FIG. 9 shows an example having three pairs of adsorption containers 10a and 10b. Of course, the adsorption containers 10a and 10b may be two pairs or four pairs or more. In this PSA type dehumidifier 1, a common heating mechanism 35 is provided for the three pairs of adsorption containers 10a and 10b. In this manner, by supplying heated air from the common heating mechanism 35 to the plurality of adsorption containers 10a and 10b, the number of heating mechanisms 35 can be reduced, the apparatus is simple, and space can be saved. . Of course, the heating mechanism 35 does not need to be permanently installed, and may be attached to the adsorption containers 10a and 10b when a heating process is necessary.

  In addition, the attachment positions of the connection port 31 and the exhaust port 45 are not limited to the wall surfaces of the adsorption containers 10a and 10b, and may be the upper pipes 20a and 20b and the lower pipes 11a and 11b as long as the heat loss of the heated air is reduced. The dehumidifier 37 of the heating mechanism 35 can use a dehumidifier such as a PTSA type or a TSA type in addition to the PSA type.

(Example 1)
FIG. 10 is a graph showing the relationship between the number of cycles (the number of repetitions of the treatment process and the regeneration process) and the dew point temperature of the low dew point air in the PSA type dehumidifier. At the beginning of the operation when the operation is resumed after replacing the adsorbent with a new one, only low dew point air having a dew point temperature of about −70 ° C. can be produced as shown by the graph line x1 in FIG. In order to produce low dew point air having a dew point temperature of −100 ° C., it is necessary to continuously operate tens of thousands of cycles (thousands of hours). Further, for example, after the dehumidifying operation has been stopped for a long time, the dew point temperature of the low dew point air obtained immediately after the start of the operation of the PSA type dehumidifier is the adsorbent in the adsorption container before the operation starts (especially the adsorption of the upper part of the adsorption container Depends on the moisture content of the material.

  Therefore, by heating the adsorbent before starting the operation of the PSA type dehumidifier and reducing the amount of water remaining in the upper part of the adsorption container at a stretch, low dew point air having a dew point temperature of −100 ° C. is supplied immediately after the start of operation. be able to. As shown by the graph line x2 in FIG. 10, when the adsorbent is heated before the start of operation, the dew point temperature of the low dew point air immediately after the start of operation is −105 ° C., and the dew point temperature does not increase and immediately after the start of operation. Thus, it was confirmed that low dew point air having a dew point temperature of −100 ° C. or lower could be continuously supplied. It is inferred that our assumption was correct.

(Example 2)
Next, the difference in the effect by the insertion position of the temperature sensor (thermocouple) which controls a heating process was examined. As shown in Fig. 11, when heating air at 250 ° C is supplied from top to bottom at 40 L (N) / min into an adsorption cylinder (adsorption container with a cylinder height of 500 mm) filled with synthetic zeolite MS-13X A numerical analysis was performed. For the thermocouple inserted in each position (100 mm, 300 mm, 400 mm, 450 mm from the bottom of the cylinder) shown in FIG. 11, the heating process is completed when the indicated value reaches 200 ° C., and then the thermocouple is cooled to 30 When the temperature reached 0 ° C., the cooling was completed, and the heating and cooling times were compared. In addition, after finishing a heating process, in order to restart an adsorption | suction process and a regeneration process after introduce | transducing cooling gas in an adsorption | suction container and cooling an adsorbent and eliminating a temperature gradient, it compared about heating / cooling time.

  The calculation results are shown in FIGS. 12 to 15 are graphs showing temporal changes in temperature of each height (100 mm, 300 mm, 400 mm, 450 mm, and 500 mm from the bottom of the cylinder) during heating and cooling. Fig. 12 shows that in a thermocouple inserted at a height of 450 mm from the bottom of the tube, the heating process is completed when the indicated value reaches 200 ° C, and then the cooling is completed when the temperature reaches 30 ° C after cooling. This is the case. FIG. 13 shows that in the thermocouple inserted at a height of 400 mm from the bottom of the cylinder, when the indicated value reaches 200 ° C., the heating process is completed, and then when the temperature reaches 30 ° C. after cooling, the cooling is completed. Is the case. FIG. 14 shows that in the thermocouple inserted at a height of 300 mm from the bottom of the cylinder, when the indicated value reached 200 ° C., the heating process was completed, and after that, when the temperature reached 30 ° C., the cooling was completed. Is the case. FIG. 15 shows that in the thermocouple inserted at a height of 100 mm from the bottom of the cylinder, when the indicated value reached 200 ° C., the heating process was completed, and after that, when the temperature reached 30 ° C., the cooling was completed. Is the case.

  In addition, the dew point temperature of the low dew point air (heated supply dew point) when the operation was restarted after heating / cooling was also compared. The results are shown in FIG. 16 (Table 1). It can be seen that when the temperature is controlled by a thermocouple (450 mm) inserted at the top of the cylinder, the resulting low dew point air cannot secure a dew point temperature of −100 ° C. or lower. On the other hand, when controlled with a thermocouple (100 mm) inserted at the bottom of the cylinder, it can be seen that although the dew point of the low dew point air is improved, the heating / cooling time is more than doubled compared to that controlled at a position 400 mm from the bottom of the cylinder. From the above, it can be seen that the time can be significantly reduced by controlling the heating / cooling time with the thermocouple inserted in the upper part of the cylinder.

  The present invention is applicable to the production of low dew point air.

It is explanatory drawing of the PSA type dehumidification apparatus concerning embodiment of this invention which shows the state which is performing the process process in one adsorption | suction container, and performing the reproduction | regeneration process in the other adsorption container. It is explanatory drawing of the PSA type dehumidification apparatus concerning embodiment of this invention which shows the state which is performing the reproduction | regeneration process in one adsorption | suction container, and is performing the process process in the other adsorption | suction container. It is explanatory drawing of the PSA type dehumidification apparatus concerning embodiment of this invention which shows the state which is performing the heating process in one adsorption container and the other adsorption container. It is explanatory drawing which shows the distribution state of the water | moisture content of the adsorbent in the adsorption container in a heating process. It is explanatory drawing which shows the temperature of the adsorbent in each height in an adsorption container. It is a graph which shows the time-dependent change of the temperature of each height in a heating process. It is explanatory drawing which shows the distribution state of the water | moisture content of the adsorbent in the adsorption container by a heating process. It is explanatory drawing of embodiment which performs a heating process using another heating mechanism for the adsorption container removed from the PSA type dehumidifier. It is explanatory drawing of the PSA type dehumidification apparatus concerning embodiment of this invention which provided one common heating mechanism with respect to three pairs of adsorption containers. It is a graph which shows the relationship between the cycle frequency in the PSA type dehumidifier in Example 1, and the dew point temperature of low dew point air. It is explanatory drawing of Example 2 which examined the difference in the effect by the insertion position of the temperature sensor (thermocouple) which controls a heating process. In a thermocouple inserted at a height of 450 mm from the bottom of the tube, when the indicated value reaches 200 ° C, the heating process is completed, and after that, when the temperature reaches 30 ° C after cooling, the tube is It is a graph which shows the time-dependent change of the temperature of each height. In a thermocouple inserted at a height of 400 mm from the bottom of the tube, the heating process is completed when the indicated value reaches 200 ° C, and then cooling is completed when the temperature reaches 30 ° C after cooling. It is a graph which shows the time-dependent change of the temperature of each height. In a thermocouple inserted at a height of 300 mm from the bottom of the tube, when the indicated value reaches 200 ° C, the heating process is completed, and after that, when the temperature reaches 30 ° C after cooling, the tube is It is a graph which shows the time-dependent change of the temperature of each height. In a thermocouple inserted at a height of 100 mm from the bottom of the tube, when the indicated value reaches 200 ° C, the heating process is completed, and after that, when the temperature reaches 30 ° C after cooling, the tube is It is a graph which shows the time-dependent change of the temperature of each height. 6 is a table 1 showing the results of comparison of the dew point temperature of the low dew point air (supply dew point after heating) when the operation was restarted after heating and cooling in Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 PSA type dehumidifier 10a, 10b Adsorption container 11a, 11b Lower piping 12 Air supply piping 15 Bypass piping 16 Exhaust piping 20a, 20b Upper piping 21 Delivery piping 25 Bypass piping 30 Heating air supply piping 34 Branch piping 35 Heating mechanism 36 Traveling carriage 37 Dehumidifier 38 Heater 41 Controller 50a, 50b Temperature sensor

Claims (6)

A PSA-type dehumidifying device that alternately performs a treatment step of passing treatment air in an adsorption container containing an adsorbent and a regeneration step of passing regeneration air to obtain low dew point air by pressure swing adsorption,
A heating mechanism for supplying high-temperature heated air into the adsorption container;
A PSA type dehumidifying device provided with a temperature sensor for measuring the temperature of the adsorbent at a position from the center of the inlet and outlet to the outlet side between the inlet and outlet of the processing air in the adsorption container. A plurality of the adsorption containers;
The PSA type dehumidifier according to claim 1, comprising a common heating mechanism for supplying heated air to each adsorption container.   The PSA type dehumidifier according to claim 1 or 2, wherein the heating mechanism includes a dehumidifier and a heater for producing heated air from the processing air. A PSA-type dehumidification method that alternately performs a treatment step of passing treatment air in an adsorption container containing an adsorbent and a regeneration step of passing regeneration air to obtain low dew point air by pressure swing adsorption,
Including a heating step of supplying high-temperature heated air into the adsorption vessel;
The PSA type dehumidification method, wherein the heating step is stopped when the temperature of a part of the adsorbent in the adsorption container reaches a predetermined temperature. A plurality of the adsorption containers;
The PSA type dehumidification method according to claim 4, wherein heated air is supplied from a common heating mechanism to each adsorption container.   The PSA type dehumidifying method according to claim 4 or 5, wherein the heating step is performed when the dehumidifying operation is resumed or when the operation is started after replacement of the adsorbent.

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