JP4351174B2 - Method for continuous supply in dehumidification of compressed gas and dehumidifier for compressed gas - Google Patents

Description

  The present invention relates to a continuous supply method and a dehumidifier for compressed gas in dehumidification of compressed gas using an adsorbent.

Conventionally, adsorption type dehumidifiers (also referred to as “heatless dryers”) continuously discharge and supply dry gas (for example, air), so adsorption of activated alumina, silica gel, synthetic zeolite, lithium chloride, etc. Two adsorption towers filled with the agent are provided.
Wet compressed air is introduced into one adsorption tower to perform adsorption drying, and the obtained dry air is supplied to a predetermined supply destination. At the same time, a part of the obtained dry air is guided to the other adsorption tower, and moisture is desorbed from the adsorbent with reduced moisture absorption capacity in the previous drying process, and this moisture is purged from the adsorption tower. Then, the adsorbent is regenerated. In this regeneration step, generally, about 20% of the obtained dry air is released into the atmosphere.
The drying process of the compressed air in one adsorption tower and the regeneration process of the adsorbent in the other adsorption tower are simultaneously performed in parallel. These drying and regeneration steps are alternately performed between the two adsorption towers. For example, the switching valve connected to both adsorption towers is switched every predetermined time. Thereby, dry air can be continuously supplied to a predetermined supply destination as product air.

In such a gas adjusting device using an adsorbent, if the operation is not stopped properly at the time of operation stop, it may not be possible to continue a suitable operation at the time of operation restart.
For this reason, in a two-column system that uses an adsorbent to concentrate oxygen from the air by the pressure swing method, the operation is started and stopped to make the oxygen concentration of the product oxygen-enriched gas extremely fast. In operation control including operation, both adsorption towers must be pressurized at a pressure higher than the atmospheric pressure specified in advance, and one of these adsorption towers must be stopped after the regeneration process is complete, There has been proposed a control method for an on-off valve in an oxygen concentrator in which an adsorption process starts from an adsorption tower after regeneration (see Patent Document 1).
JP-A-61-187916 (first page)

Similarly, in the case of the heatless dryer apparatus, when the apparatus in operation is stopped by the stop operation by the device manager, the apparatus is normally stopped under the control of the safety stop program.
As specific stop control, in order to stop the two adsorption towers in a pressure-equalized state, the stop signal (including remote switch etc.) is input to detect the time from valve switching to pressurization. The device is stopped safely.
In particular, in a relatively large heatless dryer apparatus, intake air control and purge air control are performed by a pneumatic open / close valve driven by compressed air. For this reason, it is necessary to suitably control the pneumatic open / close valve to stop the apparatus. However, when the stop signal is input as described above and controlled by the safety stop program, the apparatus can be stopped normally.

On the other hand, if a stop operation is performed without a stop signal being input due to a disturbance such as a power failure, the pneumatic open / close valve (intake valve, exhaust valve) stops at an abnormal position and cannot be restarted. There is. According to this, it becomes impossible to supply the dehumidified compressed gas continuously.
Specifically, if the pneumatic open / close valve (exhaust valve) that controls the purge air (exhaust) is not closed when the entire system is stopped, the compressed air can be turned on even if the power switch is turned on to resume operation. Always leaks from the exhaust valve. With this, the compressed air (pneumatic pressure) cannot be used by the air circuit, and the normal operation state cannot be restored.
An abnormal stop occurs when an abnormal drop in the supply voltage to the device, a momentary power failure, a power failure for several seconds, electromagnetic noise, or the like occurs. An abnormal stop also occurs due to an artificial cause. When the operation switch of the device manager is erroneously operated, the safety stop (complete stop operation) is not performed, and the same problem occurs. For example, there are frequent switch operations and sudden ON-OFF.

The problem to be solved regarding the continuous supply method and the compressed gas dehumidifying device in the dehumidification of compressed gas is that the restart operation cannot be suitably performed in some cases when the device stops abnormally, and the dehumidified compressed gas is continuously supplied. It is that it becomes impossible to supply.
Therefore, an object of the present invention is to provide a continuous supply method and a compressed gas dehumidifying device for dehumidifying compressed gas that can be continuously operated even when the apparatus is stopped abnormally and can continuously supply dehumidified compressed gas. It is to provide.

The present invention has the following configuration in order to achieve the above object.
According to one mode of the continuous supply method in the dehumidification of compressed gas according to the present invention, the compressed gas is guided to one of the two adsorption towers filled with the adsorbent, and the moisture of the compressed gas is adsorbed and dehumidified. From the adsorbent whose adsorbing capacity is reduced by introducing a drying process in which the dry gas is discharged and a part of the compressed gas dried by the drying process to the other adsorption tower where the moisture of the compressed gas is adsorbed and dehumidified in the previous process A dry gas is obtained by performing a regeneration step for regenerating the adsorbent by desorbing and exhausting moisture in parallel, and performing these drying steps and regeneration steps alternately between the two adsorption towers. the a continuous supply method in a dehumidifying compressed gas be continuously discharged, the reproduction respectively provided for each of the adsorption columns in step, exhaust bar driven to open and close by a compressed gas drying is supplied from the adsorption tower When the pressure of the compressed gas used to open and close the exhaust valve drops below a preset value, the exhaust in the regeneration process is stopped for both of the two adsorption towers. The exhaust valves on the respective adsorption towers are closed together so that the operation of the entire apparatus is stopped.

Further, according to one embodiment of the compressed gas dehumidifying device according to the present invention, a first adsorption tower and a second adsorption tower filled with an adsorbent that adsorbs and dehydrates the moisture of the introduced compressed gas, and A first suction passage for guiding compressed gas to the first adsorption tower; a second suction passage for guiding compressed gas to the second adsorption tower; a first discharge passage for discharging dry gas from the first adsorption tower; A second discharge passage for discharging dry gas from the second adsorption tower, a connection path between the adsorption towers communicating the first adsorption tower and the second adsorption tower, and a part dried by the second adsorption tower A first purge exhaust passage for exhausting compressed gas which is guided to the first adsorption tower through the connection path between the adsorption towers and desorbs moisture from the adsorbent to regenerate the adsorbent; and the first adsorption tower Part of the dried product is led to the second adsorption tower via the connection path between the adsorption towers and adsorbed. Wherein it is connected between the adsorption tower connection path as to desorb the moisture from the opening and closing the second purge exhaust passage for exhausting the compressed gas to regenerate the adsorbent, the first purge exhaust passage The first exhaust valve driven by the dry compressed gas supplied from the first adsorption tower or the second adsorption tower and the connection path between the adsorption towers to open and close the second purge exhaust passage Thus, the second exhaust valve driven by the dry compressed gas supplied from the first adsorption tower or the second adsorption tower , and the compression used for opening and closing the first exhaust valve and the second exhaust valve are used. a pressure sensor for generating a signal when the pressure of the gas is lower than a preset value, receiving a signal of the pressure sensor, and controls so that both are closed in the first exhaust valve and the second exhaust valve Comprising: a switching control unit of the gas valve, after a state in which both are closed in the first exhaust valve and the second exhaust valve by the opening and closing control means of the exhaust valve, and operation control means for stopping the operation of the entire device It is characterized by doing.

  According to one embodiment of the compressed gas dehumidifying device of the present invention, the exhaust valve opening / closing control means is provided for each of the first exhaust valve and the second exhaust valve, and receives a signal from the pressure sensor. The first electromagnetic control valve and the second electromagnetic control valve for controlling the exhaust valves to be closed and controlling the exhaust valves to be closed even when the power switch is turned off, and the two electromagnetic control valves. And a control device for controlling the system as a constituent element.

  According to the method for continuously supplying dehumidified compressed gas and the dehumidifying apparatus for compressed gas according to the present invention, even when the apparatus is stopped abnormally due to an abnormality in the compressed air supply source, etc., continuous re-operation is possible and dehumidified. There is an advantageous effect that the compressed gas can be continuously supplied.

Hereinafter, an example of the best mode of a dehumidifying device for compressed gas according to the present invention will be described in detail with reference to the accompanying drawings (FIG. 1). FIG. 1 is an air circuit diagram for explaining a compressed gas dehumidifier according to the present invention. In addition, although this form is an apparatus which dehumidifies compressed air and may be described as "air" instead of "gas", this invention is not limited to "air".
10 is a 1st adsorption tower, 20 is a 2nd adsorption tower. Hereinafter, in order to simplify the description, the first adsorption tower 10 may be described as “A tower” and the second adsorption tower 20 may be described as “B tower”. In FIG. 1, [CLM A] is indicated for the A tower and [CLM B] is indicated for the B tower. The first adsorption tower 10 (A tower) and the second adsorption tower 20 (B tower) are filled with an adsorbent that adsorbs and dehumidifies the moisture of the introduced compressed gas.

Reference numeral 11 denotes a first suction passage, which is a passage that guides compressed gas to the A tower. Reference numeral 21 denotes a second suction passage, which is a passage for guiding compressed gas to the B tower.
A first intake valve 12 is an opening / closing means for opening and closing the first intake passage 11. Reference numeral 22 denotes a second intake valve, which is an opening / closing means for opening and closing the second intake passage 21.
The first intake valve 12 and the second intake valve 22 are pneumatically operated valves that are driven by compressed gas (compressed air), and their opening and closing are controlled by the pilot valve 30. The pilot valve 30 is an electrically operated electromagnetic valve, and is controlled by a control device 50 that is electrically connected (wiring is not shown). Therefore, the pilot valve 30 and the control device 50 constitute opening / closing control means for the intake valves 12 and 22.
Reference numeral 31 denotes a compressed air inlet, and reference numeral 32 denotes an intake side filter.

Reference numeral 13 denotes a first discharge passage, which is a passage for discharging dry gas from the A tower. Reference numeral 23 denotes a second discharge passage, which is a passage through which dry gas is discharged from the B tower.
14 and 24 are check valves, which are provided in the first discharge passage 13 and the second discharge passage 23, respectively. The check valves 14 and 24 are check valves that suitably discharge the dry gas discharged as the product gas and prevent the backflow.
Reference numeral 35 denotes a discharge passage for product air, which is connected to the first discharge passage 13 and the second discharge passage 23 via check valves 14 and 24. 36 is a filter on the exhaust side, and 37 is an outlet for product air.
With the above configuration, drying is performed in which the compressed gas is guided to one of the two adsorption towers 10 and 20 filled with the adsorbent, and the moisture of the compressed gas is adsorbed and dehumidified to discharge the dry gas. Means are configured.

Reference numeral 33 denotes a connection path between the adsorption towers, which is a passage that connects the A tower and the B tower. The inter-adsorption tower connection path 33 is connected to the side where the discharge passages 13 and 23 of the adsorption towers 10 and 20 are communicated. This is because, instead of the compressed air that has just been sucked into the adsorption towers 10 and 20 and contains moisture, the dried compressed gas is guided from one adsorption tower to the other adsorption tower.
In addition, a purge orifice 34 is provided in the inter-adsorption tower connecting path 33 as means for adjusting the gas flow rate. Thereby, the compressed air of a fixed flow volume passes.

  Reference numeral 15 denotes a first purge exhaust passage, and a part dried in the tower B is led to the tower A via the inter-adsorption tower connection path 33 to desorb moisture from the adsorbent to regenerate the adsorbent. It is a passage for exhausting compressed gas. Reference numeral 25 denotes a second purge exhaust passage, and a part of the air dried by the tower A is guided to the tower B via the inter-adsorption tower connection path 33 to desorb moisture from the adsorbent and regenerate the adsorbent. It is a passage for exhausting compressed gas.

Reference numeral 16 denotes a first exhaust valve, which is a pneumatic on-off valve that is driven by compressed air so as to open and close the first purge exhaust passage 15. Reference numeral 26 denotes a second exhaust valve, which is a pneumatic on-off valve that is driven by compressed air so as to open and close the second purge exhaust passage 25.
Reference numeral 17 denotes a first electromagnetic control valve that controls the opening and closing of the first exhaust valve 16 by switching the compressed air flow path. When compressed air is introduced into the closing drive air passage 18, the first exhaust valve 16 is closed, and when pressurized air is introduced into the opening drive air passage 19, the first exhaust valve 16 is opened. Reference numeral 27 denotes a second electromagnetic control valve that controls the opening and closing of the second exhaust valve 26 by switching the compressed air flow path. When pressurized air is introduced into the closing drive air passage 28, the second exhaust valve 26 is closed, and when pressurized air is introduced into the opening drive air passage 29, the second exhaust valve 26 is opened.
The electromagnetic control valves 17 and 27 are two-position control valves that control the exhaust valves 16 and 26 to close when the power switch is turned off. The electromagnetic control valves 17 and 27 are electrically operated electromagnetic valves, and are controlled by a control device 50 that is electrically connected (wiring is not shown). Therefore, the electromagnetic control valves 17 and 27 and the control device 50 constitute opening / closing control means for the exhaust valves (16 and 26).
A silencer 49 is provided to mute the sound generated by the purge air exhausted from the exhaust valves 16 and 26.

  With the above configuration, a part of the compressed gas dried in the drying step is led to the other adsorption tower where the moisture of the compressed gas is adsorbed and dehumidified in the previous step, and moisture is desorbed from the adsorbent whose adsorption capacity is reduced. Regeneration means for performing a regeneration step of exhausting and regenerating the adsorbent in parallel with the drying step is configured.

A pressure sensor 40 is connected to the flow path 41 on the compressed air supply source side, and generates a signal when the pressure (air pressure) on the supply source side falls below a preset value.
In response to the signal of the pressure sensor 40, the exhaust valve opening / closing control means including the electromagnetic control valves 17 and 27 and the control device 50 as described above closes both the first exhaust valve 16 and the second exhaust valve 26. To control.
The control device 50 stops the operation of the entire device after both the first exhaust valve 16 and the second exhaust valve 26 are closed by the exhaust valve opening / closing control means. Thus, the control device 50 of this embodiment also functions as an operation control unit and controls the entire device.

The pressure sensor 40 of this embodiment is connected to a flow path 41 that supplies driving air for each control valve (the pilot valve 30, the first electromagnetic control valve 17, and the second electromagnetic control valve 27). Further, in this embodiment, the flow paths 41 a and 41 b connected to the A tower side and the B tower side across the orifice 34 of the inter-adsorption tower connection path 33 merge to form the flow path 41. The flow path 41 is supplied with dry air processed in the tower A or tower B as drive air for each control valve, and is suitable as a part for detecting air pressure. The mounting position of the pressure sensor 40 is not limited to this. For example, the pressure sensor 40 is provided in the passage 61 in the vicinity of the humidity sensor 60 that has substantially the same pressure as the air pressure of the driving air of each control valve on the dry air discharge side. Also good.
In addition, check valves 42 and 42 are arranged in the middle of the flow paths 41a and 41b connected to the A tower side and the B tower side. Reference numeral 45 is a pressure meter, and 43 and 62 are filters.

Next, the operation of the present embodiment will be described in detail with reference to FIG.
First, the operation during normal operation will be described.
In the state shown in FIG. 1, all the solenoids of each control valve (pilot valve 30, first electromagnetic control valve 17, second electromagnetic control valve 27) are not energized, and each control valve is in an OFF state. It has become. That is, the entire apparatus is in an OFF state.
In this state, even when compressed air (driving air) for driving is supplied to the pilot valve 30, the pilot valve 30 is in the central closed position, and either the first intake valve 12 or the second intake valve 22 is located. In contrast, drive air is not supplied.
On the other hand, when the driving air is supplied to the first electromagnetic control valve 17 and the second electromagnetic control valve 27, the driving air is output so that the first exhaust valve 16 and the second exhaust valve 26 are kept closed. To do.

Next, a description will be given of a case where the drive air is supplied to each control valve and energized, and the entire apparatus is operated in a steady state.
One solenoid (right side in the drawing) of the pilot valve 30 is energized, and the connection switching means on one side (right side in the drawing) of the pilot valve 30 is connected to the driving air passage (passage indicated by the dotted line in the drawing). Is done. Then, the first intake valve 12 is opened and the second intake valve 22 is closed by the drive air supplied through the pilot valve 30. Thereby, the compressed air is introduced into the A tower through the intake valve 12, and the compressed air dried in the A tower is discharged as product air through the first discharge passage 13.
For a predetermined period of time during this period, the solenoid of the second electromagnetic control valve 27 is energized, so that one of the second electromagnetic control valves 27 (the left side in the drawing) is connected to the drive air passages 28 and 29. Connected, the second exhaust valve 26 opens. As a result, a part of the compressed air dried in the tower A is introduced into the tower B through the inter-adsorption tower connection path 33, and the compressed air that has regenerated the adsorbent in the tower B is purged from the second exhaust valve 26. As exhausted.

Then, the other solenoid (left side in the drawing) of the pilot valve 30 is energized, and the connection switching means on the other side (left side in the drawing) of the pilot valve 30 is connected to the drive air passage. Then, the second intake valve 22 is opened and the first intake valve 12 is closed. Thereby, the compressed air is introduced into the B tower through the intake valve 22, and the compressed air dried in the B tower is discharged as product air through the second discharge passage 23.
For a predetermined period of time during this period, the solenoid of the first electromagnetic control valve 17 is energized, so that one of the first electromagnetic control valves 17 (the left side in the drawing) is connected to the drive air passages 18 and 19. Connected, the first exhaust valve 16 opens. As a result, a part of the compressed air dried in the tower B is introduced into the tower A through the inter-adsorption tower connection path 33, and the compressed air that has regenerated the adsorbent in the tower A is purged from the first exhaust valve 16. As exhausted.
By repeating the above series of steps alternately, the dried compressed air can be continuously supplied.

Next, the case where the apparatus is stopped will be described focusing on the operation of the exhaust valves 16 and 26.
When the power switch is turned off and a stop signal is issued and the safety program appropriately stops, each control valve (pilot valve 30, first electromagnetic control valve 17, second electromagnetic control valve 27) is in a non-energized state. If there is no pressure change at the inlet 31 and the outlet 37, the air pressure applied to each control valve is maintained.
According to this, when the power switch is turned off, both the electromagnetic control valves 17 and 27 are in a non-energized state and return to the state shown in FIG. That is, the electromagnetic control valves 17 and 27 are controlled to close the exhaust valves 16 and 26. Immediately after the power switch is turned off, the compressed air (drive air) has a sufficient air pressure. Therefore, the exhaust valves 16 and 26 are closed by being controlled by the electromagnetic control valves 17 and 27. In addition, by closing the exhaust valves 16 and 26 in this way, the pressure in the two adsorption towers 10 and 20 is equalized, and then the entire apparatus is stopped.
Therefore, when the operation is resumed, the air pressure for operating the air circuit can be suitably obtained without leaking from the exhaust valves 16, 26, and the apparatus can be suitably restarted.

Even when the apparatus is abnormally stopped due to an abnormal situation in which the pressure (pneumatic pressure) on the compressed air supply source side is reduced regardless of the stop signal, according to the present embodiment, the apparatus can be appropriately stopped as follows. .
When the air pressure decreases, the pressure sensor 40 detects it and generates an analog signal.
Upon receiving the signal, the control device 50 electrically controls the solenoids of both the electromagnetic control valves 17 and 27 so that they are not energized (OFF state shown in FIG. 1). As a result, while the air pressure is sufficient to control the exhaust valves 16 and 26, the exhaust valves 16 and 26 are closed by being controlled by the electromagnetic control valves 17 and 27. By closing the exhaust valves 16 and 26 in this way, the pressure in the two adsorption towers 10 and 20 is equalized. Thereafter, the entire apparatus is stopped by the operation control means comprising the control device 50.
Therefore, when the operation is resumed, the air pressure for operating the air circuit can be suitably obtained without causing the compressed air to leak from the exhaust valves 16 and 26, as in the case of the normal stop. The apparatus can be suitably restarted.
For this reason, even when the apparatus is abnormally stopped, it is possible to continue the operation again, and there is an advantageous effect that the dehumidified compressed gas can be continuously supplied.
Note that when the compressor stops due to an abnormality on the compressed air supply source (compressor) side, if the power of the compressor is separate and the electricity stops for some reason, including artificial causes, There are cases where the usage amount is higher than expected and the air pressure drops, or the piping is damaged.

  As described above, the present invention has been variously described with reference to preferred embodiments. However, the present invention is not limited to these embodiments, and many modifications can be made without departing from the spirit of the invention. Of course you get.

It is a circuit diagram showing one embodiment of a dehumidifying device for compressed gas according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 1st adsorption tower 11 1st suction passage 12 1st intake valve 13 1st discharge passage 15 1st purge exhaust passage 16 1st exhaust valve 17 1st electromagnetic control valve 20 2nd adsorption tower 21 2nd suction passage 22 2nd 2 intake valve 23 second exhaust passage 25 second purge exhaust passage 26 second exhaust valve 27 second electromagnetic control valve 30 pilot valve 33 adsorption tower connection path 40 pressure sensor 50 control device

Claims (3)

A drying step of discharging the dry gas by introducing the compressed gas to one of the two adsorption towers filled with the adsorbent and the moisture of the compressed gas being adsorbed and dehumidified;
A part of the compressed gas dried in the drying step is led to the other adsorption tower where the moisture of the compressed gas is adsorbed and dehumidified in the previous step, and the moisture is desorbed and exhausted from the adsorbent whose adsorption capacity is reduced. In parallel with the regeneration process to regenerate the adsorbent,
A continuous supply method in dehumidification of compressed gas in which the drying gas is continuously discharged by alternately performing the drying step and the regeneration step alternately between the two adsorption towers,
In the regeneration step, each adsorption tower is provided , and an exhaust valve that is opened and closed by dry compressed gas supplied from the adsorption tower is operated to control exhaust,
When the pressure of the compressed gas used for opening / closing driving of the exhaust valve drops below a preset value, the exhaust gas in the regeneration process is stopped in each of the two adsorption towers. The exhaust valves are closed together,
Thereafter, the operation of the entire apparatus is stopped, and the continuous supply method in the dehumidification of the compressed gas. A first adsorption tower and a second adsorption tower filled with an adsorbent that adsorbs and dehydrates the moisture of the introduced compressed gas; and
A first suction passage for guiding compressed gas to the first adsorption tower, and a second suction passage for guiding compressed gas to the second adsorption tower;
A first discharge passage for discharging dry gas from the first adsorption tower, and a second discharge passage for discharging dry gas from the second adsorption tower;
A connection path between the adsorption towers communicating the first adsorption tower and the second adsorption tower;
A part dried in the second adsorption tower is led to the first adsorption tower via the inter-adsorption tower connecting path, and moisture is desorbed from the adsorbent to exhaust the compressed gas regenerated by the adsorbent. The first purge exhaust passage and a part dried in the first adsorption tower are led to the second adsorption tower via the inter-adsorption tower connection path, and moisture is desorbed from the adsorbent to remove the adsorbent. A second purge exhaust passage for exhausting the regenerated compressed gas;
The first exhaust driven by the dry compressed gas supplied from the first adsorption tower or the second adsorption tower by being connected to the connection path between the adsorption towers so as to open and close the first purge exhaust passage. It is driven by the dry compressed gas supplied from the first adsorption tower or the second adsorption tower by being connected to the connection path between the adsorption towers so as to open and close the valve and the second purge exhaust passage. A second exhaust valve;
A pressure sensor that generates a signal when the pressure of the compressed gas used to open and close the first exhaust valve and the second exhaust valve drops below a preset value;
An exhaust valve opening / closing control means for controlling the first exhaust valve and the second exhaust valve to be closed in response to a signal from the pressure sensor;
After a state in which both are closed in the first exhaust valve and the second exhaust valve by the opening and closing control means of the exhaust valve, compressed gas, characterized by comprising a driving control means for stopping the operation of the entire device Dehumidifier.   The exhaust valve opening / closing control means is provided for each of the first exhaust valve and the second exhaust valve, and controls each exhaust valve to close by receiving a signal from the pressure sensor, and when the power switch is turned off. In addition, the first electromagnetic control valve and the second electromagnetic control valve that control the exhaust valves to be closed, and a control device that electrically controls the two electromagnetic control valves are constituent elements. Item 3. A compressed gas dehumidifier according to Item 2.

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