JP2002136831A - Dehumidifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a device and/or to improve the reliability of the device. SOLUTION: In the dehumidifying device in which the moisture of compressed air is removed by alternately operating plural dehumidifying towers and the compressed air from which the moisture is removed is supplied to an air-driving device as power source, an auxiliary dehumidifying means is provided at a preceding stage of the dehumidifying tower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dehumidifier for compressed air supplied to a pneumatic drive such as a cylinder as a power source.

[0002]

2. Description of the Related Art In a nuclear power plant, for example, an air cylinder is used for driving a control valve. In order to improve the reliability of the operation, dehumidification of compressed air supplied to the air cylinder is performed. This dehumidification is for preventing the operation of the air cylinder from becoming unstable due to the entry of moisture into the compressed air. For such dehumidification, for example, a type in which the moisture of the compressed air is removed by alternately operating two dehumidification towers and the compressed air from which the moisture has been removed is supplied to an air cylinder as a power source. It is used.

[0003]

In the above-mentioned conventional type of dehumidifier, the relative humidity of the compressed air supplied to each dehumidifying tower is designed to be 100%, that is, the humidity at the dehumidifying capacity limit of the dehumidifying tower is reduced. Compressed air with a relative humidity of 1
(00% compressed air), it is difficult to reduce the size of the dehumidification tower to reduce the size of the dehumidifier, and to switch the supply of compressed air to each dehumidification tower. It has been difficult to improve the reliability of the switching valve.

The present invention has been made in view of the above-described problems, and has as its object to reduce the size of an apparatus and / or improve the reliability of the apparatus.

[0005]

In order to achieve the above object, according to the present invention, as a first means, a plurality of dehumidification towers are alternately operated to remove the moisture of the compressed air, and the moisture is removed. A dehumidifying device for supplying the compressed air thus obtained to a pneumatic driving device as a power source, which employs a means including an auxiliary dehumidifying means in front of a dehumidifying tower.

As a second means, a means in which a hollow fiber membrane is used as the auxiliary dehumidifying means in the first means is adopted.

[0007] As a third means, in the first or second means, the dehumidifying tower at rest is configured to discharge moisture removed from the compressed air by the heated air supplied from the heated air generating means to the outside. Is adopted.

[0008] As a fourth means, in the first or second means, the dehumidifying tower at rest is a means for reducing the internal pressure to vaporize the water removed from the compressed air and discharging the water to the outside. adopt.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a dehumidifier according to the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a system diagram of a heating / regenerating type dehumidifying apparatus according to the first embodiment. In this figure, reference numerals 1A to 1D denote on-off valves, 2A to
2I is a control valve (cylinder drive control valve), 3 is a pre-filter, 4 is a hollow fiber membrane (auxiliary dehumidifying means), 5A and 5B are dehumidifying towers, 6A and 6B are check valves, 7 is an after filter, and 8 is a blower. , 9 are electric heaters. In addition, the blower 8 and the electric heater 9 constitute a heated air generating unit in the present embodiment.

The on-off valve 1A is interposed between a control valve 2A and an upstream compressor for supplying compressed air X0 to the heating / regenerating type dehumidifier.
It is interposed between the load driven by the pressure of 0 and the after filter 7. Here, the compressed air X0 contains moisture, and the present heating and regeneration type dehumidifier removes this moisture, and the dried compressed air X3 obtained by the removal treatment is removed.
Is supplied to the load.

The control valve 2A is provided for regulating the supply of the compressed air X0 to the main heating / regenerating type dehumidifying apparatus. Of compressed air X0 supplied from the apparatus is made to flow into the main heating / regeneration type dehumidifier. The pre-filter 3 is provided for dust removal of the compressed air X0 flowing through the control valve 2A, and supplies the compressed air X1 from which impurities have been removed to the hollow fiber membrane 4.

The hollow fiber membrane 4 is provided before the dehumidifying towers 5A and 5B in order to remove a part of the moisture in the compressed air, and is a constituent element of the heating / regenerating type dehumidifying apparatus. is there. The hollow fiber membrane 4 is formed by assembling a large number of hollow fibers having a large number of micropores formed therein, and by passing compressed air X1 through the micropores, only a certain amount of water is filtered off to reduce the water ratio. The compressed air X2 is supplied to the dehumidifying towers 5A and 5A.
Send to B. The hollow fiber membrane 4 is provided as an auxiliary, and does not dry the compressed air X1 to a sufficient level, that is, a level that can be supplied to a load.

The dehumidifying towers 5A and 5B are for drying the compressed air X2 to a sufficient level, and are provided at the subsequent stage of the hollow fiber membrane 4. These dehumidification towers 5A and 5B
The control valves 2B to 2D and the check valves 6A and 6B, which will be described later, are operated alternately at fixed time intervals. The dehumidifying towers 5A and 5B are filled with activated alumina having a size of 3 to 4 mm balls in a full state, and the activated alumina removes moisture in the compressed air X2 by a moisture adsorption action. Such dehumidification towers 5A and 5B are the most central components in the present heating and regeneration type dehumidifier, and the size of the equipment governs the size of the present dehumidifier.

The compressed air X3 from which the moisture has been sufficiently removed by the dehumidifying towers 5A and 5B is supplied to the after-filter 7, but the compressed air X2 is supplied to the dehumidifying towers 5A and 5B, and the compressed air X3 of the compressed air X3 is removed. Supply to the control valve 2B ~
2I and check valves 6A and 6B. The switching of the opening and closing operation of these control valves 2B to 2D and the operation of the check valves 6A and 6B allow the dehumidification tower 5 to operate.
A and 5B are supplied with the compressed air X2, and the compressed air X3 from which moisture has been removed from one of the dehumidifying towers 5A and 5B to which the compressed air X2 has been supplied is supplied to the after-filter 7. It has become.

The control valve 2B is provided between the hollow fiber membrane 4 and the dehumidifying tower 5A, and the control valve 2C is provided between the hollow fiber membrane 4 and the dehumidifying tower 5B. These control valves 2B and 2C are for supplying the compressed air X2 to either the dehumidifying tower 5A or the dehumidifying tower 5B. The check valve 6A is located between the dehumidifying tower 5A and the after-filter 7, and the check valve 6B is located between the dehumidifying tower 5A and the after-filter 7.
This is a valve interposed between B and the after-filter 7. These check valves 6A and 6B are connected to the dehumidifying tower 5A or the dehumidifying tower 5A.
B for supplying the compressed air X3 to the after-filter 7 from any one of B.

The after-filter 7 is for removing impurities (attributable to the activated alumina) contained in the compressed air X3. Most of the compressed air X3 that has been subjected to the dust removal processing by the after-filter 7 is supplied to an air cylinder, which is a load, but a part of the compressed air X3 is returned to the dehumidifying tower 5A or 5B which is inactive. I have. The control valves 2F and 2G are provided in such a return path, and the control valve 2F is provided between the after-filter 7 and the dehumidifying tower 5A, while the control valve 2G is provided between the after-filter 7 and the dehumidifying tower 5B. Are provided between them. These control valves 2F and 2G are for supplying the compressed air X4 to either the dehumidifying tower 5A or the dehumidifying tower 5B.

The blower 8 blows external air to the electric heater 9. The electric heater 9 heats the external air sent from the blower 8 and supplies it to the dehumidifying tower 5A or 5B at rest via the control valve 2H or the control valve 2I. The blower 8 and the electric heater 9 are provided for drying the activated alumina in the dehumidifying tower 5A or 5B whose operation has been stopped after the operation for a certain period of time, and the control valve 2H or the control valve 2I. Dehumidification tower 5A or dehumidification tower 5
By supplying heated air to B, the water adsorbed on the activated alumina is vaporized and discharged to the outside.

The control valve 2H is provided between the electric heater 9 and the dehumidifying tower 5A, and the control valve 2I is provided between the electric heater 9 and the dehumidifying tower 5B. These control valves 2
H and 2I are for supplying the heating air of the electric heater 9 to either the dehumidifying tower 5A or the dehumidifying tower 5B.
Further, the control valves 2D and 2E are for selectively discharging the water vapor of the adsorbed moisture of the activated alumina from either the dehumidifying tower 5A or the dehumidifying tower 5B to the outside via the on-off valve 1C.

Next, the operation of the heating / regenerating type dehumidifying apparatus thus configured will be described in detail. In the normal operation of the present dehumidifier, the dehumidifying towers 5A and 5B are operated alternately as described above. In the following description, as an example, the dehumidifying tower 5A is dehumidified (moisture adsorption by activated alumina).
The case where B is regenerated (removal of water adhering to activated alumina) will be described.

In this case, the control valves 2B, 2E,
2I is opened and the control valves 2C, 2D, 2F, 2
G and 2H are closed. That is, the compressed air X0 containing moisture is removed by the pre-filter 3 and part of the moisture is removed by the hollow fiber membrane 4, and then the compressed air X2 is sent to the dehumidifying tower 5A via the open control valve 2B as compressed air X2. Supplied. Then, by the action of the activated alumina in the dehumidification tower 5A, the dehumidification is performed to a level required for load supply. The compressed air X3 output from the dehumidifying tower 5A is supplied to the after-filter 7 via the check valve 6A, and after being removed by the after-filter 7, is output toward the load via the on-off valve 1B. .

During the operation of the dehumidification tower 5A, the dehumidification tower 5B in which activated alumina inside has adsorbed moisture by the previous operation is subjected to the internal drying treatment as follows. In other words, the operation of the blower 8 and the electric heater 9 supplies heated air to the dehumidifying tower 5B via the open control valve 2I. As a result, the adsorbed water of the activated alumina is vaporized, and the open control valve 2E is opened. Is discharged to the outside. When the activated alumina in the dehumidifying tower 5B is sufficiently dried in this way, the closed control valve 2G is shifted to the open state, and a part of the compressed air X4 flows into the dehumidifying tower 5B. . Due to the inflow of the compressed air X4, the activated alumina in the dehumidifying tower 5B in a heated state is cooled, and the original moisture adsorption action is regenerated.

When the moisture adsorption performance of the activated alumina in the dehumidifying tower 5B is regenerated in this way, the dehumidifying tower 5B is switched to the dehumidifying state, and the dehumidifying tower 5A that has been operated is switched to the regenerating state. This dehumidifying tower 5
The time interval between A and 5B operation switching is about several hours (for example, 8 hours).
The activated alumina in the dehumidifying tower 5B has adsorbed a considerable amount of water due to such continuous operation for a long time, and accordingly, it takes time to dry the activated alumina in the dehumidifying tower 5B. Therefore, forced drying with the above heated air is required.

According to the present embodiment, the dehumidification is not performed by only one stage of the dehumidification towers 5A and 5B, but the compressed air X2 from which a part of the moisture has been removed in advance by the hollow fiber membrane 4 in the preceding stage.
Is finally dehumidified by the dehumidification towers 5A and 5B,
Dehumidification towers 5A and 5 that control the size of the dehumidifier
It is possible to make the device size of B smaller than before. That is, in the related art, the dehumidification tower was designed on the assumption that compressed air having a relative humidity of 100% was input. However, by removing a part of the moisture with the hollow fiber membrane 4 in advance as in the present dehumidifier, Since the relative humidity is reduced by the amount of water removed, the required amount of activated alumina can be reduced, and the dehumidification towers 5A and 5B can be downsized.

When the equipment size of the dehumidifying towers 5A and 5B is unchanged, the addition of the hollow fiber membrane 4 reduces the amount of water adsorbed by the dehumidifying towers 5A and 5B per unit time. It is possible to set the operation switching intervals of 5A and 5B to a longer time interval than before. Therefore,
Control valves 2B to 2I functioning as switching valves and check valve 6
It is possible to improve the durability of A and 6B, that is, to improve the reliability of the present heating and regeneration type dehumidifier.

[Second Embodiment] FIG. 2 is a system diagram of a non-heating regeneration type dehumidifier according to the second embodiment. In this figure, the same components as those of the above-described first embodiment are denoted by the same reference numerals. Since the components having the same reference numerals are duplicated, description thereof will be omitted below.

In this figure, reference numerals 11A to 11D denote pilot operated piston valves (hereinafter simply referred to as piston valves), 12 denotes a control valve, and 13 denotes a purge exhaust valve.
An assembly, 14 is a muffler, 15A to 15D are check valves, and 16 is a flow control valve. The piston valve 11A is interposed between the hollow fiber membrane 4 and the dehumidification tower 5A, and the piston valve 11B is interposed between the hollow fiber membrane 4 and the dehumidification tower 5B.
These piston valves 11A and 11B are for selectively supplying the compressed air X2 to either the dehumidifying tower 5A or the dehumidifying tower 5B. The check valve 15A is located between the dehumidifying tower 5A and the after-filter 7, and the check valve 15B is located in the dehumidifying tower 5B.
And the after-filter 7. These check valves 15A and 15B are for selectively discharging the compressed air X3 from either the dehumidifying tower 5A or the dehumidifying tower 5B.

The flow control valve 16 is provided with the check valve 15A, 1
5B and the common node of the check valves 15C and 15D, and is interposed between the check node 15A and the check valve 15C.
A part of the compressed air X3 discharged from B is supplied to the dehumidifying tower 5A or 5B via the check valve 15C or the check valve 15D as compressed air for drying. In addition, the check valve 15C is composed of the flow control valve 16 and the dehumidifying tower 5A.
And the check valve 15D is interposed between the flow control valve 16 and the dehumidification tower 5B.

The piston valve 11C is connected to the dehumidifying tower 5A and the control valve 1
2, the piston valve 11D is connected to the dehumidifying tower 5B and the control valve 1
2 are interposed. These piston valves 11C and 11D remove the compressed air for drying input from the dehumidifying tower 5A or 5B via the flow rate control valve 16 and the moisture adhering to the activated alumina in the dehumidifying tower 5A or 5B to the exhaust gas. For discharging to the outside. The control valve 12 includes the piston valves 11C and 11D.
Common node and purge exhaust assembly 13
And is opened during normal operation.

Purge exhaust assembly 13
Are interposed between the control valve 12 and the muffler 14, and the piston valves 11C and 11D are provided from the dehumidifying tower 5A or 5B.
The purpose of this is to reduce the flow rate of the exhaust gas rapidly discharged through the dehumidifying tower 5A or the dehumidifying tower 5A or the dehumidifying tower 5B to prevent friction due to the oscillation of the activated alumina. The muffler 14 is for reducing exhaust noise generated when exhaust gas is discharged to the outside.

Next, the operation of the non-heat regeneration type dehumidifier configured as described above will be described in detail. For example, the dehumidifying tower 5A is dehumidified (moisture adsorption by activated alumina).
When B is regenerating (removing water adhering to the activated alumina), the piston valves 11A and 11D are opened, and the piston valves 11B and 11C are closed. In this state, the compressed air X2 partially removed by the hollow fiber membrane 4 in advance is supplied only to the dehumidifying tower 5A and reaches a level required for load supply by the action of the activated alumina in the dehumidifying tower 5A. Dehumidified.

As a result of such dehumidification, most of the compressed air X3 output from the dehumidification tower 5A is supplied to the after-filter 7 via the check valve 15A opened by the positive pressure in the dehumidification tower 5A. After the dust is removed by the after filter 7, the dust is output to the load via the on-off valve 1B.

The compressed air in the dehumidifying tower 5B is supplied to the piston valve 1
1D is forcibly shifted instantaneously from the closed state to the open state, that is, the inside of the dehumidifying tower 5B is rapidly opened to the outside air.
As a result, the pressure inside the dehumidifying tower 5B is rapidly reduced from a certain positive pressure state to the atmospheric pressure, so that the moisture adsorbed on the activated alumina evaporates instantaneously to become steam, and the control valve 12, the purge exhaust Assembly 13 and muffler 14
Exhausted through. A part of the compressed air X3 set by the flow control valve 16 is supplied to the dehumidifying tower 5B via the check valve 15D, and is further regenerated by the dehumidified air.

As described above, in the present non-heating regeneration type dehumidifier, the adsorbed water of the activated alumina is vaporized by rapidly reducing the pressure of the dehumidifying tower 5B on the regeneration side, and the vapor is discharged to the outside to activate the dehumidification. The alumina is dried to regenerate the moisture adsorption performance. Then, when the water adsorption performance of the activated alumina of the dehumidifying tower 5B is regenerated, the dehumidifying tower 5B
Is switched to the dehumidification state, and the dehumidification tower 5A which has been in the dehumidification state is switched to the regeneration state.

The switching interval between the dehumidifying towers 5A and 5B is extremely short as compared with the case of the above-mentioned heating / regenerating type dehumidifying apparatus, and is set to, for example, about several minutes (about three minutes). Therefore, the amount of adsorbed moisture in one operation of the dehumidification towers 5A and 5B is smaller than that of the heating and regeneration type dehumidifier,
This small amount of water is easily turned into steam by the sudden pressure drop described above.

In such a non-heating regenerating type dehumidifying apparatus, as in the case of the heating regenerating type dehumidifying apparatus described above,
Since the hollow fiber membrane 4 is provided before the dehumidifying tower 5A, the dehumidifying tower 5
The device size of A and 5B can be made smaller than before. Further, it is possible to set the operation switching interval of the dehumidifying towers 5A and 5B to a longer time interval than before, and thus to improve the durability of the piston valves 11A to 11D and the check valves 15A to 15D functioning as switching valves. That is, it is possible to improve the reliability of the present non-heat regeneration type dehumidifier.

The present invention is not limited to the above embodiment, and for example, the following modifications can be considered.

(1) In each of the above embodiments, the hollow fiber membrane 4 is used as the auxiliary dehumidifying means, because the auxiliary dehumidifying means is maintenance-free. By providing the hollow fiber membrane 4 after the pre-filter 3, the hollow fiber membrane 4
Is supplied with compressed air X1 containing only water after removal of impurities, so that the micropores of the hollow fiber membrane 4 are not blocked by the impurities, so that the hollow fiber membrane 4 is semi-permanent. A constant dehumidification performance can be maintained.
However, if the maintainability of the auxiliary dehumidifying means is not taken into consideration, it is possible to use another desiccant instead of the hollow fiber membrane 4. For example, it is conceivable to use silica gel or the like as the desiccant.

(2) Each of the above embodiments employs two dehumidifying towers 5
A and a dehumidifying apparatus having a heating and regenerating method and a non-heating and regenerating method are provided. However, the number of dehumidifying towers is not limited to two. The present invention can be applied in principle to a heat regeneration type dehumidifier and a non-heat regeneration type dehumidifier having more dehumidification towers.

[0040]

As described above, the dehumidifier according to the present invention has the following effects. (1) Since the auxiliary dehumidifying means is provided at the preceding stage of the dehumidifying tower, the relative humidity of the compressed air supplied to each dehumidifying tower is lower than 100%. Therefore, since the capacity of the dehumidification tower can be provided, the dehumidification tower can be downsized and the dehumidification apparatus can be downsized. (2) When the size of the dehumidification tower is kept at the conventional size, the operation switching interval of the dehumidification tower can be set to a longer time interval than before by the relative humidity of the compressed air being lower than 100%. Therefore, the durability of the switching valve can be improved, that is, the reliability of the dehumidifying device can be improved.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a first embodiment of the present invention, that is, a heating / regenerating type dehumidifying apparatus.

FIG. 2 is a system diagram showing a second embodiment of the present invention, that is, a non-heating regeneration type dehumidifier.

[Explanation of symbols]

1A to 1D open / close valve 2A to 2I control valve 3 prefilter 4 hollow fiber membrane (auxiliary dehumidifying means) 5A, 5B dehumidifying tower 6A, 6B check valve 7 after filter 8 Blower (heating air generating means) 9 Electric heater (heating air generating means) 11A to 11D Pilot operation piston valve (piston valve) 12 Control valve 13 Purge exhaust assembly 14 Muffler 15A to 15D Check valve 16 Flow control valve

Claims (4)

[Claims] 1. A dehumidifier that removes moisture from compressed air by alternately operating a plurality of dehumidification towers (5A, 5B), and supplies the compressed air from which the moisture has been removed to a pneumatic drive as a power source. A dehumidifier comprising an auxiliary dehumidifier (4) at a stage preceding the dehumidifier (5A, 5B). 2. The dehumidifier according to claim 1, wherein the auxiliary dehumidifier is a hollow fiber membrane. 3. The dehumidifying tower (5B), which is at rest, discharges water removed from compressed air by the heated air supplied from the heated air generating means (8, 9) to the outside. Or the dehumidifier according to 2. 4. The dehumidifying apparatus according to claim 1, wherein the dehumidifying tower (5B) which is inactive is configured to reduce internal pressure to vaporize water removed from the compressed air and discharge it to the outside. .