JP2003088723A - Air dryer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact air dryer wherein the capacity of an adsorption cylinder 4 is low and the electric capacity of a heater 7 is suppressed. SOLUTION: Compressed air compressed by a compressor 20 condensed by a cooler 21 is dried up to a dew point of -20 deg.C using a heatless air dryer 2 and the dried air is treated in one adsorption cylinder 4A to form ultra-dry air which is, in turn, supplied to an ozone generator 22 through supply piping. Further, heat exchange is performed between the ultra-dry air passed through the adsorption cylinder 4A and compressed high temperature air supplied by bypass piping 11 using a heat exchanger 10 and the ultra-dry air heated by the heater 7 is used to regenerate the adsorbent 8 of other adsorption cylinder 4B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air dryer incorporated in an ozone generator used for advanced water treatment of tap water and sewage, waste liquid treatment of pulp mills and the like.

[0002]

2. Description of the Related Art Conventionally, in an ozone generator used for advanced treatment of sewage and industrial waste liquid, air, which is a raw material for ozone generation, is dried at a low temperature to a dew point of -40 to -60 ° C. I had to send it in. Therefore, the air dryer 101 is often incorporated in the ozone generator.

FIG. 2 shows the structure of a conventional air dryer 101. In FIG. 2, an air drying device 101 includes a compressor 20 for compressing raw material air, and a compressor 2
Cooler 21 for condensing air compressed by 0
Are connected.

A refrigerating air dryer 102 for removing water from condensed compressed air is connected to the cooler 21, and a pressure reducing valve 3 is provided at a subsequent stage of the refrigerating air dryer 102.

The pressure reducing valve 3 is connected to a suction cylinder 4 via a switching valve 5A.
It is connected to either A or the suction cylinder 4B. In FIG. 2, the switching valve 5A is set in the direction of the solid line, and the air dried by the refrigerating air dryer 102 passes through the pressure reducing valve 3 and is supplied to the adsorption cylinder 4A. The adsorption cylinder 4B is connected to the discharge pipe 9 by a switching valve 5A. The pair of adsorption cylinders 4 are filled with an adsorbent 8 made of silica gel or alumina gel.

A switching valve 5B is connected to the adsorption cylinder 4A and the adsorption cylinder 4B. In FIG. 2, the switching valve 5B is set in the direction of the solid line, and the air that has passed through the switching valve 5B from the adsorption cylinder 4A is sent to the ozone generator 22 through the pipe. Further, the switching valve 5A and the switching valve 5B operate in synchronism, and when one of them is switched, the other one is switched at the same time, and the functions of the adsorption cylinders 4A and 4B can be switched.

A regeneration air pipe 13 is provided in the middle of the pipe to the ozone generator 22, and the regeneration air pipe 13 is for heating the on-off valve 6 and the dry air for regenerating the adsorbent 8. Heater 7 is provided.

The outlet side of the heater 7 is connected to the switching valve 5B, and the dry air passing through the heater 7 is supplied to the adsorption cylinder 5B.

In the air drying device 101 having the above-mentioned structure, the raw material air is compressed and heated to 130 ° C. by the compressor 20 and condensed to 35 ° C. by the cooler 21.

Next, the compressed air sent from the cooler 21 is pressurized by the refrigerating air dryer 102 at a pressurized dew point of 5 ° C.
Dry to a degree. This dry air passes through the pressure reducing valve 3 and is supplied to the switching valve 5A. Since the switching valve 5A is set on the solid line side, dry air is supplied to the adsorption cylinder 4A.

The supplied dry air is adsorbed with water by the adsorbent 8 in the adsorption cylinder 4A. The temperature of the air rises by the amount of heat of adsorption generated when adsorbing this moisture, and it becomes super dry air with a dew point of -60 ° C or less at about 15 ° C and is sent out from the adsorption cylinder 4A. It lasts for hours.

The ultra-dry air at 15 ° C. sent from the adsorption cylinder 4A is supplied to the ozone generator 22 through the switching valve 5B. At this time, a part of the ultra dry air is supplied to the heater 7 through the open / close valve 6 which is in an open state. After being heated by the heater 7, it is supplied to the adsorption cylinder 4B through the switching valve 5B. The high temperature dry air supplied to the adsorption cylinder 4B is dried by heating the adsorbent 8 to regenerate the adsorbent 8. After regenerating the adsorbent 8, the air is discharged from the discharge pipe 9 to the outside of the machine through the switching valve 5A.

As described above, in the conventional air dryer 101, the compressed air is dehumidified in the adsorption cylinder 4A, and at the same time, the adsorbent 8 is regenerated in the other adsorption cylinder 4B.

[0014]

However, these two adsorption cylinders 4 required to constantly dry the air occupy 1/3 of the installation area of the device. Further, the ultra-dry air that has passed through the adsorbent 8 is heated and used for the regeneration of the adsorbent 8. However, when the capacity of the adsorption cylinder 4 increases as the amount of treated air increases, the adsorbent 8 that is also heated. Increased,
As a result, the electric capacity of the heater 7 also increases.

Further, since the water-cooling type cooler 21 and the refrigeration type air dryer 102 use water as a coolant, a water pipe, a cooling water monitoring instrument, condensed water, a drain pipe, etc. are required in the apparatus. , These complicate the device.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a compact air dryer having a small adsorption cylinder capacity and a reduced electric capacity of the heater 7.

[0017]

In order to achieve the above object, an air drying apparatus according to the invention of claim 1 cools the compressor for generating compressed hot air and the compressed hot air from this compressor. A cooler is provided outside the apparatus, and has a supply pipe for taking in compressed air from the cooler, and a pair of adsorption cylinders in which an adsorbent is connected and connected to the supply pipe. Dry air is generated from compressed air, and at the same time, in the other adsorption column, the adsorbent is regenerated using the heated dry air in which a part of the dry air is heated, and the adsorption air regeneration function and adsorbent regeneration of both adsorption columns In an air drying device configured to alternately switch the function and the function, an intake unit that takes in the compressed hot air from the compressor, and the compressed hot air that is taken in from the intake unit. Using a heat exchange means for heating a part of the dry air that has passed through the adsorption cylinder by heat exchange, and a delivery means for delivering the compressed high temperature air discharged from the heat exchange means to the cooler. Is characterized by.

According to the invention of claim 1, the temperature of the super dry air can be raised by exchanging heat with the heat exchanger, and the electric capacity of the heater can be suppressed.
In addition, it is possible to obtain the effect that the load on the cooler and the air dryer can be reduced. Therefore, it is possible to provide a compact air dryer having a small adsorption cylinder capacity and a reduced electric capacity of the heater.

An air drying device according to a second aspect of the present invention is the air drying device according to the first aspect, wherein a pipe path for supplying the compressed air to the adsorption cylinder producing dry air is provided. A heatless air dryer for removing moisture from the compressed air is provided.

According to the second aspect of the present invention, the amount of water removed by the adsorbent can be reduced to 1/4 by drying the compressed high temperature air to a dew point of -20 ° C using a heatless air dryer. Therefore, the amount of adsorbent required to dry the air becomes 1/4, and the adsorption cylinder can be made smaller. Further, since the amount of heated dry air also decreases as the amount of the adsorbent decreases, the electric capacity of the heater for heating the air can be reduced. Therefore, it is possible to provide a compact air dryer having a small adsorption cylinder capacity and a reduced electric capacity of the heater.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an air dryer of the present invention will be described below with reference to FIG.

The air dryer 1 shown in FIG. 1 is provided with a heatless air dryer 2 for drying the compressed air compressed by the external compressor 20 and condensed by the cooler 21. Further, the heat exchanger 10 is installed on the piping path between the on-off valve 6 and the heater 7.
A pipe from the compressor 20 to the cooler 21 is once drawn into the air drying device 1, and a bypass pipe 11 for supplying the compressed hot air from the compressor 20 to the heat exchanger 10 is provided on the pipe path.

The rest of the structure is the same as the conventional one, and is composed of a pressure reducing valve 3, a pair of adsorption cylinders 4 and a pair of switching valves 5, an opening / closing valve 6 and a heater 7, and pipes connecting them. The switching valve 5A connects the pressure reducing valve 3 and the adsorption cylinder 4A,
Further, the adsorption cylinder 4 and the discharge pipe 9 are connected.

The switching valve 5B includes an adsorption cylinder 4B and an ozone generator 2
2 or the on-off valve 6 is connected, and the heater 7 and the adsorption cylinder 4A are connected. Further, each adsorption column 4 contains an adsorbent 8 made of silica gel or alumina gel.

First, the heat exchanger 10 will be described.

A heat pipe is used for the heat exchanger 10. The heat pipe has a capillary structure on the inner wall of the metal pipe, and the inside is evacuated, and a small amount of water
It is a heat transfer element in which alternative CFCs are sealed. When one end of the heat pipe is heated, the working liquid evaporates (heat is absorbed by the latent heat of vaporization) and becomes a vapor flow that moves to the low temperature part at high speed. Next, it contacts the tube wall and is cooled and condensed (release of heat by latent heat of condensation), and the condensate returns to the heating section due to capillary phenomenon or gravity, and the cycle of evaporation → movement → condensation is repeated again to continue heat. Move very efficiently.

In the heat exchanger 10, the heat radiating side (condensing part) of the heat pipe is attached to the regeneration air pipe 13 connected to the heater 7, and the heat input side (evaporating part) is connected to the bypass pipe 11. The heat of the compressed hot air, which is attached and supplied from the compressor 20, is transferred to the super dry air.
Further, the bypass pipe 11 from the heat exchanger 10 to the cooler 21
A check valve 12 is installed on the top as a backflow prevention device.

As a method of adjusting the amount of heat to be moved,
A method of adjusting the flow rate of the compressed high-temperature air sent to the heat exchanger 10 can be considered, and the thickness of the bypass pipe 11 and the solenoid valve,
The flow rate adjustment method based on the opening degree of the electric valve can be improved.

The air compressed by the compressor 20 reaches a high temperature of about 130 ° C. and is sent to the cooler 21,
A part is supplied to the heat exchanger 10 through the bypass pipe 11. Further, the 15 ° C. dry air (details described later) discharged from the adsorption cylinder 4A is sent to the ozone generator 22, but a part of the dry air passes through the open / close valve 6 in the open state and the heat exchanger 1
Sent to 0.

In the heat exchanger 10, the high temperature compressed air of 130 ° C. sent from the compressor 20 and the dry air of 15 ° C. exchange heat via the heat pipe. Compressor 20
The heated dry air heated by the high-temperature compressed air from is further heated by the heater 7 to a temperature necessary for regenerating the adsorbent 8, and is sent to the adsorption cylinder 4B through the switching valve 5B.

The heated dry air sent to the adsorption cylinder 4B through the heater 7 dries the adsorbent 8 and passes through the other side of the switching valve 5A and is discharged from the discharge pipe 9 to the outside of the machine. The compressed high-temperature air obtained by heating the dry air is sent to the cooler 21 through the return pipe of the bypass pipe 11.

By using the heat exchanger 10 in this manner, the dry air for regenerating the adsorbent can be heated, and the load on the heater 7 can be reduced, so that the electric capacity can be reduced. Further, by exchanging heat, the temperature of the compressed air sent from the compressor 20 to the cooler 21 can be lowered, and the load on the equipment below the cooler 21 can be reduced.

Next, the function of the heatless air dryer 2 will be described.

The compressed high temperature air compressed by the compressor 20 reaches a temperature of about 130 ° C. and is sent to the cooler 21. The cooler 21 allows hot air to have a dew point of 5 ° C under pressure.
Is condensed and sent to the heatless air dryer 2.

The compressed air condensed by the cooler 21 is dried to a dew point of -20 ° C. by the heatless air dryer 2 and is sent to the adsorption cylinder 4A through the pressure reducing valve 3. The air introduced into the adsorption cylinder 4A is adsorbed with moisture by the adsorbent 8. The temperature of the air rises by the amount of heat of adsorption generated when adsorbing this moisture, and becomes dry air having a dew point of -60 ° C or lower at about 15 ° C and is sent out from the adsorption cylinder 4A. Since the subsequent operation is the same as the conventional one, the description is omitted.

In the conventional air dryer 101, the adsorbent 8 is used.
The amount of water removed by 4 was 4.1 g / m ³ , but the amount of water removed by the adsorbent 8 was 5 g by cooling the compressed air to a dew point of -20 ° C using the heatless air dryer 2.
/ m ³ By using the heatless air dryer 2 to cool the dew point to -20 ° C, the amount of water removed is 1/4.
Therefore, the amount of the adsorbent 8 required to dry the air is 1/4.

Therefore, the capacity of the adsorption cylinder 4 containing the adsorbent 8 is only 1/4, and the adsorption cylinder 4 can be made smaller. Further, since the amount of the adsorbent 8 is reduced and the required amount of heated dry air is also reduced, the electric capacity of the heater 7 for heating the air can be reduced.

The present invention is not limited to the above configuration example, and various modifications can be made. Figure 1 shows an example using the heatless air dryer 2, but the dew point is -20 ° C.
Any dryer that can dry up to can be used in the present invention. Moreover, although the example which used the heat pipe for the heat exchanger 10 was shown, the double pipe, the shell-and-tube type heat exchanger, the compact type heat exchanger, etc. can be mentioned in addition. Further, when the heat exchanger 10 alone can sufficiently heat the air, the heater 7 may not be used.

[0039]

As described above, according to the inventions of claims 1 and 2, the moisture removed by the adsorbent is obtained by drying the compressed high temperature air to a dew point of -20 ° C using a heatless air dryer. The amount can be reduced to 1/4. Therefore, the amount of adsorbent required to dry the air becomes 1/4, and the adsorption cylinder can be made smaller. Further, since the amount of heated dry air also decreases as the amount of the adsorbent decreases, the electric capacity of the heater for heating the air can be reduced. Therefore, it is possible to provide a compact air dryer having a small adsorption cylinder capacity and a reduced electric capacity of the heater.

By exchanging heat with the heat exchanger, the temperature of the super dry air can be raised and the electric capacity of the heater can be further suppressed. In addition, it is possible to obtain the synergistic effect that the loads of the cooler and the heatless air dryer can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram of the present invention.

FIG. 2 is a schematic view of a conventional air dryer.

[Explanation of symbols]

1 Air dryer 2 Heatless air dryer 3 pressure reducing valve 4A, 4B adsorption cylinder 5A, 5B switching valve 6 open / close valve 7 heater 8 Adsorbent 9 discharge pipe 10 heat exchanger 11 Bypass piping 12 Check valve 13 Piping for recycled air 20 compressor 21 Cooler 22 Ozone generator 101 air dryer 102 Refrigerating air dryer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ryutaro Makise             1-1 Shibaura, Minato-ku, Tokyo Co., Ltd.             Toshiba headquarters office F-term (reference) 4D052 AA01 BA01 BA03 CD00 DA02                       DA06 DA08 DB01 FA06 HA01                       HA02

Claims (2)

[Claims] 1. A compressor that generates compressed hot air and a cooler that cools the compressed hot air from the compressor are provided outside the apparatus, and a supply pipe that takes in compressed air from the cooler and the supply pipe are provided. And a pair of adsorption cylinders in which an adsorbent is connected, and one of the adsorption cylinders produces dry air from the compressed air, while the other adsorption cylinder simultaneously heats a part of the dry air. In an air drying device configured to regenerate an adsorbent by using dry air, and alternately perform the dry air generating function and the adsorbent regenerating function of both adsorption cylinders, compressed hot air from the compressor. And a heat exchange means for heating a part of the dry air that has passed through the adsorption cylinder by heat exchange by using the intake means for taking in the compressed hot air taken in from the intake means, An air drying device comprising: a delivery unit that delivers the compressed high-temperature air discharged from the heat exchange unit to the cooler. 2. The air drying apparatus according to claim 1, further comprising a heatless air dryer that removes water from the compressed air on a pipe path that supplies the compressed air to the adsorption cylinder that is producing dry air. An air drying device characterized by the above.