JP6741196B2 - Air compression system - Google Patents

Description

The present invention relates to an air compression system using a water addition type compressor.

Conventionally, as disclosed in FIG. 1 of Patent Document 1 below, a screw-type water-lubricated air compressor (1) in which a pair of rotors (37) are supported at both ends by water-lubricated slide bearings (2), A separator (6) for separating a discharge fluid (compressed air discharged together with lubricating water) from the compressor (1) into water and water, and cooling water returned from the separator (6) to between the rotors of the compressor (1). There is known an air compression system including an air-cooling heat exchanger (10) for cooling and an aftercooler (11) for cooling compressed air from the separator (6). In this system, a water pipe (23) from the air-cooling heat exchanger (10) to the rotor of the compressor (1) is branched into a bearing water supply pipe (23), and the branched water is frozen. It is supplied to the bearing (2) of the compressor (1) via the heat absorbing heat exchanger (33) of the cycle (27) or via the bypass pipe (24).

JP, 2010-43589, A (paragraphs [0012]-[0017], Drawing 1).

In the prior art, the discharge fluid from the compressor is discharged to the separator tank (6) as it is, and after air-water separation, the compressed air is sent to the outside through the aftercooler (11), while the separation water is cooled by air cooling heat. It is returned to the compressor via the exchanger (10). Therefore, in the separator tank, the fluid from the compressor is introduced as it is, that is, without being separated into water and water in advance or cooled, and is maintained at a relatively high temperature. Therefore, the amount of water taken out to the outside with the compressed air from the separator tank increases, and a large amount of water to be replenished from the outside is necessary to compensate for it. Moreover, in order to cool the compressed air, an aftercooler must be installed downstream of the separator tank. Further, in the conventional technique, the heat of compression generated in the compressor is discarded to the outside air in the air-cooled heat exchanger (10, 11) and is not recovered.

Therefore, the problem to be solved by the present invention is to provide an air compression system capable of reducing the amount of water taken out to the outside in association with the compressed air from the separator tank, and consequently reducing the amount of makeup water supplied from the outside. .. Another object of the present invention is to provide an air compression system that can omit the installation of an aftercooler downstream of the separator tank. Further, it is preferable to provide an air compression system that can recover the compression heat of the compressor.

The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 is to add water to the suction air and to cool and lubricate the compression chamber seal and the compression mechanism by this addition water. water addition type compressor, accept the fluid discharged from the compressor, and the pre-separator steam separator to the discharge fluid in the added water and the compressed air, the compressed air after the gas-water separator in the pre-separator By separately receiving the added water, and separating the compressed air into water and vapor, and comprising a separator tank for storing the added water, the gas phase portion of the pre-separator, the separator tank of the pre-separator via the gas phase communication passage. Connected to a gas phase portion, the liquid phase portion of the pre-separator is connected to the liquid phase portion of the separator tank through a liquid phase communication passage, the gas phase portion of the separator tank, a delivery path of compressed air The liquid phase portion of the separator tank is connected to a return path of the added water to the compressor, and the gas phase communication passage is provided with an aftercooler for cooling compressed air. Is provided with a water cooler for cooling the added water .

According to the invention described in claim 1, the discharge fluid from the water-added type compressor is separated into steam and water by the pre-separator, and the compressed air after separation of the steam and water is cooled by the after cooler, while the added water is cooled by the water cooler. After cooling with, supply to the separator tank. Therefore, the separator tank is supplied with the fluid that has been separated from the water vapor in advance and cooled, and is maintained at a relatively low temperature. Therefore, it is possible to reduce the amount of water that is taken out to the outside together with the compressed air from the separator tank, and consequently to reduce the amount of supplementary water supplied from the outside. Further, the installation of the aftercooler in the compressed air delivery passage and the installation of the water cooler in the added water return passage downstream of the separator tank are not essential and can be omitted. By separating air and water by the pre-separator and cooling the compressed air by the after cooler and cooling the added water by the water cooler, the heat exchange efficiency in each cooler can be improved.
The invention according to claim 2 is a water supply passage that is connected to an air intake passage to the compressor and that is provided with a water supply valve, and a drainage passage that is connected to the bottom of the separator tank and that is provided with a drainage valve. The air compression system according to claim 1, further comprising: a water level detector provided in the separator tank; and a controller that controls the water supply valve and the drain valve according to the water level detected by the water level detector. System.

In the invention according to claim 3 , the aftercooler is a heat exchanger between compressed air and cooling water flowing through the gas phase communication passage , and the water cooler is an additive water flowing through the liquid phase communication passage. It is a heat exchanger with cooling water, and warms the said cooling water in each said cooler, and produces hot water, The air compression system of Claim 1 or Claim 2 characterized by the above-mentioned.

According to the invention described in claim 3 , hot water can be produced by recovering the compression heat and heating the water flow in the aftercooler and the water cooler.

The invention according to claim 4 is the air compression system according to claim 3 , wherein the cooling water is passed through the aftercooler and then through the water cooler.

According to the invention described in claim 4 , hot water can be produced by sequentially passing cooling water through the aftercooler and the water cooler to heat them. By passing the cooling water through the aftercooler first, the compressed air can be cooled as desired by the cooling water having a relatively low temperature. Then, the cooling water heated thereby is passed through a water cooler, whereby the cooling water can be further heated.

Further, the invention according to claim 5, said delivery path, any one of the preceding claims, characterized in that the primary pressure adjusting valve to hold the separator tank above the set pressure is provided The air compression system according to item 1.

According to the invention described in claim 5 , by maintaining the inside of the separator tank at a set pressure or more, the added water can be reliably returned from the separator tank to the compressor.

According to the air compression system of the present invention, it is possible to reduce the amount of water that is taken out to the outside with the compressed air from the separator tank, and in turn reduce the amount of makeup water supplied from the outside. Further, the installation of the aftercooler downstream of the separator tank is not essential and can be omitted. Furthermore, it is possible to produce hot water by recovering the compression heat of the compressor.

It is a schematic diagram showing an air compression system of one example of the present invention.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing an embodiment of the present invention, and shows an air compression system 1 for producing compressed air and a heat recovery system 2 capable of recovering compression heat by the air compression system 1. That is, in this embodiment, the air compression system 1 includes the heat recovery system 2, and conversely, the heat recovery system 2 is applied to the air compression system 1. Hereinafter, the air compression system 1 and the heat recovery system 2 will be described in order.

<<Structure of the air compression system 1>>
First, the configuration of the air compression system 1 of this embodiment will be described. The air compression system 1 of the present embodiment includes a water-added compressor 3, a pre-separator 4 that separates the fluid discharged from the compressor 3 into steam and water, and a compressed air that has been separated from steam by the pre-separator 4. An after-cooler 5 for cooling, a water cooler 6 for cooling the separated water after the steam separation by the pre-separator 4, and a separator tank 7 to which the compressed air and the separated water after passing through the respective coolers 5, 6 are supplied. Prepared as a main part.

The compressor 3 is a water addition type air compressor. The type of the compressor 3 is not particularly limited, but is, for example, a screw type or a scroll type. The water-added compressor 3 has water (typically purified water (pure water) or softened water) added to the air suction port, and the added water is used for sealing the compression chamber and cooling the compression mechanism. Meanwhile, the air is compressed and discharged. During this discharge, the additive water is also discharged together with the compressed air.

The compressor 3 is driven by the electric motor 8 in the illustrated example, but may be driven by another prime mover. For example, the compressor 3 may be driven by a steam motor (steam engine). Further, the compressor 3 may be on/off controlled or capacity controlled (output adjusted). For example, in the compressor 3, the electric motor 8 is on/off controlled, or the rotation speed of the electric motor 8 is inverter controlled. Alternatively, in the case of a steam motor, the opening/closing or opening of the steam supply valve to the steam motor is controlled.

When the compressor 3 is operated, outside air is sucked into the compressor 3 from the suction passage 10 via the air filter 9, and at that time, as will be described later in detail, via the added water return passage 11 from the separator tank 7. Water is added at the set flow rate. Then, the air compressed in the compressor 3 is discharged to the pre-separator 4 together with the added water. A check valve 13 is provided in the discharge passage 12 from the compressor 3 to the pre-separator 4.

The water-added compressor 3 can also be referred to as a water-lubricated compressor or a water-injected compressor (in other words, these may be included). Further, here, the compressor 3 has water added to the air suction port, but a water supply port may be provided in addition to the air suction port, and water may be added to this water supply port.

The pre-separator 4 receives the discharge fluid (compressed air discharged together with the added water) from the compressor 3 and separates it into water and water. That is, the fluid discharged from the compressor 3 is divided into compressed air and separated water in the pre-separator 4. Along with this, the inside of the pre-separator 4 is divided into an upper gas phase portion and a lower liquid phase portion. The gas phase part of the pre-separator 4 is connected to the gas phase part of the separator tank 7 via the gas phase communication passage 14, while the liquid phase part of the pre-separator 4 is connected via the liquid phase communication passage 15. It is connected to the liquid phase part of the separator tank 7.

An aftercooler 5 is provided in the gas-phase communication passage 14 from the pre-separator 4 to the separator tank 7. The aftercooler 5 is means for cooling the compressed air after the water separation by the preseparator 4. Here, as the heat recovery heat exchanger 16 that recovers the compression heat, the aftercooler 5 exchanges heat without mixing the compressed air and the cooling liquid. In the aftercooler 5, the compressed air is cooled by the cooling liquid, while the cooling liquid is warmed by the compressed air.

A water cooler 6 is provided in the liquid-phase communication passage 15 from the pre-separator 4 to the separator tank 7. The water cooler 6 is means for cooling the separated water after the steam separation by the pre-separator 4. Here, as the heat recovery heat exchanger 16 that recovers the compression heat, the water cooler 6 exchanges heat without mixing the separated water and the cooling liquid. In the water cooler 6, the separated water is cooled by the cooling liquid, while the cooling liquid is heated by the separated water.

The separator tank 7 receives the compressed air and the separated water that have passed through the coolers 5 and 6 and separates them into water and water. The compressed air from the pre-separator 4 is cooled by the after-cooler 5 to condense water, and the water is removed by the separator tank 7. Therefore, the inside of the separator tank 7 is also divided into an upper gas phase portion and a lower liquid phase portion. The fluid is supplied from the pre-separator 4 to the separator tank 7 through the communication passages 14 and 15 by the discharge pressure of the compressor 3 and the head pressure difference.

In addition to the above-described gas phase communication passage 14, the compressed air delivery passage 17 to the compressed air utilization portion is connected to the gas phase portion of the separator tank 7. The compressed air delivery passage 17 is provided with a primary pressure adjusting valve 18 and a check valve 19 in order from the separator tank 7 side. The primary pressure adjusting valve 18 is a valve that keeps the inside of the separator tank 7 at a set pressure or higher during operation of the compressor 3. Here, the primary pressure regulating valve 18 is a self-operated valve that mechanically operates based on the pressure on the primary side (that is, the separator tank 7 side), but in some cases, the pressure on the primary side is monitored by a sensor, It may be an electric valve that is controlled based on the detected pressure. In addition, in the present embodiment, the gas phase portion of the separator tank 7 is provided with a safety valve 20 and an air discharge valve 21 for exhausting to the outside. The primary pressure adjusting valve 18 and the check valve 19 may be configured as an integral valve mechanism.

The liquid phase portion of the separator tank 7 is connected to the above-mentioned liquid phase communication passage 15 and the addition water return passage 11 to the compressor 3. The added water return passage 11 is provided with an added water valve 22 and a water filter 23 in order from the separator tank 7 side. By opening the added water valve 22 during operation of the compressor 3, the stored water in the separator tank 7 can be returned to the compressor 3 via the added water return passage 11. At that time, the added water can be returned from the separator tank 7 to the compressor 3 by sucking the compressor 3 into operation by the operation of the compressor 3 and pressurizing the inside of the separator tank 7. The primary pressure adjusting valve 18 keeps the inside of the separator tank 7 at a set pressure or more, and as described later, the pressure in the compressed air delivery passage 17 (and thus the pressure in the separator tank 7) is maintained at a desired level. Therefore, the added water can be supplied to the compressor 3 at a set flow rate while the added water valve 22 functions as an orifice. Moreover, when the additive water is supplied from the separator tank 7 to the compressor 3, the water filter 23 can remove impurities.

The air compression system 1 further includes a water supply passage 24 and a drainage passage 25. The water supply passage 24 is a means for supplying water from a water supply source such as an ion exchange device (for example, a mixed bed type deionizing device or a water softening device) as added water. In the present embodiment, the water supply passage 24 from the water supply source is branched into a first water supply passage 24A and a second water supply passage 24B, and the first water supply passage 24A is connected to the suction passage 10 to the compressor 3, The second water supply passage 24B is connected to the separator tank 7. The first water supply passage 24A is provided with a first water supply valve 26, while the second water supply passage 24B is provided with a check valve 27 and a second water supply valve 28 in order. In this embodiment, the first water supply valve 26 is an electromagnetic valve and the second water supply valve 28 is a manual valve.

On the other hand, the drainage channel 25 is connected to the bottom of the separator tank 7. The drainage channel 25 is provided with a drainage valve 29. By opening the drainage valve 29, drainage from the inside of the separator tank 7 can be achieved.

In addition, the separator tank 7 is provided with a water level detector 30. The water level detector 30 is not particularly limited in its configuration, but is, for example, a float type water level detector capable of detecting the water level of purified water/condensed water containing no ions. Further, a pressure sensor 31 is provided in the compressed air delivery passage 17 from the separator tank 7 downstream of the primary pressure adjusting valve 18 and the check valve 19. The pressure sensor 31 can monitor the discharge pressure of compressed air (the pressure supplied to the compressed air utilizing portion).

<<Operation of the air compression system 1>>
Next, the operation of the air compression system 1 of this embodiment will be described. Basically, a series of controls described below are automatically performed by a controller (not shown). That is, the controller is connected to the compressor 3 (specifically, the motor 8 thereof), the discharge valve 21, the addition water valve 22, the first water supply valve 26, the drain valve 29, the water level detector 30, the pressure sensor 31, and the like. The compressor 3 and the valves 21, 22, 26, 29 and the like are controlled based on the detection signals of the water level detector 30 and the pressure sensor 31.

First, the flow of air will be described. When the operation of the compressor 3 is started, the compressor 3 sucks in air through the air filter 9, compresses it, and discharges it. The compressed air discharged from the compressor 3 is sent from the compressed air delivery passage 17 to the compressed air utilization unit via the pre-separator 4, the after cooler 5, and the separator tank 7. However, since the primary pressure adjusting valve 18 is provided in the compressed air delivery passage 17, the primary pressure adjusting valve 18 is closed when the pressure in the separator tank 7 is low, such as immediately after the start of the operation. No compressed air is delivered to the air utilization section. When the pressure on the primary side of the primary pressure adjusting valve 18 (that is, the separator tank 7 side) becomes equal to or higher than the set pressure, the primary pressure adjusting valve 18 opens and compressed air is delivered to the compressed air utilizing portion.

During operation of the compressor 3, the compressor 3 is controlled so as to maintain the pressure detected by the pressure sensor 31 at the target pressure. For example, the motor 8 of the compressor 3 is on/off controlled or inverter controlled. The target pressure is higher than the set pressure of the primary pressure regulating valve 18. Therefore, thereafter, basically, the inside of the separator tank 7 is maintained at the target pressure.

By opening the added water valve 22 during operation of the compressor 3, water can be added to the suction port of the compressor 3 at a set flow rate. Thereby, sealing, cooling and lubrication of the compressor 3 can be achieved. Compressed air from the compressor 3 is discharged to the pre-separator 4 together with the added water. Then, the pre-separator 4 separates air and water. The compressed air that has been separated into water and water by the pre-separator 4 is cooled by the aftercooler 5, and is further separated into water and water by the separator tank 7, and is sent out from the compressed air sending passage 17. On the other hand, the separated water in the pre-separator 4 is cooled in the water cooler 6, then stored in the separator tank 7, and can be supplied to the compressor 3 via the added water return passage 11.

During operation of the compressor 3, the water level in the separator tank 7 is maintained at the set water level. For example, when the water level detected by the water level detector 30 exceeds the upper limit water level, the drain valve 29 is opened to lower the water level to a predetermined level. Conversely, when the water level detected by the water level detector 30 falls below the lower limit water level, the first water supply valve 26 is opened to raise the water level to a predetermined level. While the first water supply valve 26 is open, makeup water is supplied to the separator tank 7 via the compressor 3. During this time, the added water valve 22 may be closed. It should be noted that while the compressor 3 is stopped, the second water supply valve 28 can be opened to directly supply water to the separator tank 7.

On the other hand, when the compressor 3 is stopped, the air release valve 21 is opened. The reverse rotation of the compressor 3 can be prevented by opening the discharge valve 21 even when the compressor 3 is stopped. After that, when the compressor 3 is restarted, the discharge valve 21 is closed.

According to the air compression system 1 of the present embodiment, the discharge fluid from the compressor 3 is separated into water and water by the pre-separator 4, and the compressed air after separation of water and water is cooled by the after cooler 5, while the separated water is cooled by the water cooler. After being cooled in 6, it is supplied to the separator tank 7. Therefore, the separator tank 7 is supplied with the fluid that has been separated into steam and water in advance and cooled, and is maintained at a relatively low temperature. Preferably, the temperature inside the separator tank 7 is maintained below the dew point temperature of the compressed air. Therefore, it is possible to reduce the amount of water taken out to the outside together with the compressed air from the separator tank 7, which in turn reduces the amount of supplementary water supplied from the outside, thereby reducing the running cost. Further, it is not essential to install a second aftercooler in the compressed air delivery passage 17 or to install a second water cooler in the added water return passage 11, and it is basically unnecessary.

Further, according to the air compression system 1 of the present embodiment, the pre-separator 4 separates air and water, and the compressed air is cooled by the after cooler 5 and the separated water is cooled by the water cooler 6, so that each cooler is cooled. The heat exchange efficiency in 5 and 6 can be improved. Along with this, the heat exchangers forming the coolers 5 and 6 can be downsized.

<<Structure of heat recovery system 2>>
Next, the configuration of the heat recovery system 2 of this embodiment will be described. The heat recovery system 2 of the present embodiment is a system that recovers heat by using the compression heat of the compressor 3 to heat the cooling liquid, and is configured to be able to switch the presence or absence of heat recovery.

The cooling liquid is not particularly limited, but is typically water. As this water, softening water, purified water (pure water), or the like can be used in addition to tap water depending on the application. For example, when preheating the water supply to the steam boiler using the heat recovery system 2, softened water that has been degassed as described below is used. Hereinafter, the cooling liquid will be described as water (that is, cooling water), but the same applies to other liquids. In other words, in the following, the cooling water may be a cooling liquid other than water instead of literal water.

The heat recovery system 2 of the present embodiment includes a heat recovery heat exchanger 16 (aftercooler 5 and water cooler 6) that heats cooling water by the compression heat of the compressor 3 and the heat recovery heat exchanger 16. Cooling water inlet passage 32, cooling water outlet passage 33 from the heat recovery heat exchanger 16, cooling water return passage 34 connecting the outlet passage 33 and the inlet passage 32, and a liquid passage described later. A switching unit 35 (heat recovery valve 36, return valve 37) for switching between the circulation path and the circulation path, and a radiator 38 for cooling the circulation cooling water in the circulation path are provided as main parts.

The heat recovery heat exchanger 16 is the aftercooler 5 and the water cooler 6 in this embodiment. In the aftercooler 5, the compressed air and the cooling water are exchanged with each other to cool the compressed air with the cooling water and heat the cooling water with the compressed air. The heat of compression possessed by the compressed air can be used to heat the cooling water for heat recovery. On the other hand, the water cooler 6 exchanges heat between the added water (separated water in the pre-separator) and the cooling water to cool the added water with the cooling water while warming the cooling water with the added water. The heat of compression of the added water can be used to heat the cooling water to recover heat.

In the present embodiment, cooling water is passed through the aftercooler 5 and the water cooler 6 in order. Therefore, in this embodiment, the aftercooler 5 and the water cooler 6 are connected by the connecting path 39. Then, the cooling water is made to flow from the inlet passage 32 to the outlet passage 33 through the aftercooler 5, the connecting passage 39 and the water cooler 6 in this order. Hereinafter, the after cooler 5 and the water cooler 6 connected by the communication path 39 are collectively referred to as a heat recovery heat exchanger 16.

A pump 40, a check valve 41, and a radiator 38 are sequentially provided in the inlet passage 32 from the water supply source to the heat recovery heat exchanger 16 toward the heat recovery heat exchanger 16. By operating the pump 40, the cooling water can be passed through the heat recovery heat exchanger 16. The radiator 38 is an air-cooled type in this embodiment, and exchanges heat between the cooling water and the outside air (ventilated by the fan 38A). Although the details will be described later, for example, when the cooling water temperature at the inlet side of the radiator 38 is higher than the outside air temperature, the fan 38A of the radiator 38 is operated to cool the cooling water by ventilation by the fan 38A.

A heat recovery valve 36 is provided in the outlet path 33 from the heat recovery heat exchanger 16. During operation of the compressor 3, by opening the heat recovery valve 36 and operating the pump 40, cooling water can be passed through the heat recovery heat exchanger 16 to recover the compression heat. In the present embodiment, the heat recovery valve 36 is composed of an electric valve whose opening can be adjusted.

The outlet passage 33 upstream of the heat recovery valve 36 and the inlet passage 32 upstream of the pump 40 are connected by a return passage 34. At this time, it is preferable to provide a cooling water storage tank 42 at the connection point between the inlet passage 32 and the return passage 34. However, the storage tank 42 may be omitted in some cases. Further, the storage tank 42 may be provided in the inlet path 32, not at the connection point with the return path 34, but downstream thereof (preferably upstream of the pump 40 ). The pump 40 is provided downstream of the connection point with the return path 34 in the inlet path 32, and also upstream of the connection point with the return path 34 in the communication path 39 and the outlet path 33. It may be provided.

A return valve 37 is provided in the return path 34. The return valve 37 is composed of an electric valve in this embodiment. Although details will be described later, by selectively opening only one of the heat recovery valve 36 and the return valve 37, the cooling water after passing through the heat recovery heat exchanger 16 is returned to the return path 34. It is possible to switch between returning to the inlet passage 32 via the return passage 34 and sending to the downstream of the outlet passage 33 without passing through the return passage 34.

In this embodiment, the switching means 35 is composed of a heat recovery valve 36 and a return valve 37. By switching the opening and closing of the heat recovery valve 36 and the return valve 37, the flow path of the cooling water can be switched to either the liquid passage path or the circulation path described below.

The liquid passage is realized by opening the heat recovery valve 36 with the return valve 37 closed. The liquid passage is a passage that includes the inlet passage 32, the heat recovery heat exchanger 16, and the outlet passage 33, but does not include the return passage 34. When the pump 40 is operated with the liquid passage, the cooling water from the inlet passage 32 is discharged through the heat recovery heat exchanger 16 and the heat recovery valve 36 of the outlet passage 33 ( State of heat recovery implementation). At this time, the storage tank 42 is appropriately supplied with water from a water supply source. In other words, the water from the water supply source is supplied to the inlet passage 32 while the pump 40 is operating in the liquid passage.

The circulation path is realized by opening the return valve 37 with the heat recovery valve 36 closed. The circulation path is a path including the inlet path 32 on the downstream side of the connection point of the return path 34, the heat recovery heat exchanger 16, the outlet path 33 on the upstream side of the connection point of the return path 34, and the return path 34. is there. When the pump 40 is operated in the circulation path, the cooling water from the pump 40 is returned to the pump 40 and circulated through the heat recovery heat exchanger 16 and the return passage 34. At that time, by operating the radiator 38, the circulating cooling water can be cooled in the radiator 38 (heat recovery stop state). It is not necessary to supply new water from the water supply source to the storage tank 42 while circulating the cooling water in the circulation path.

The outlet passage 33 is provided with a hot water outlet temperature sensor 43 on the outlet side of the heat recovery valve 36. On the other hand, in the inlet passage 32, a feed water temperature sensor (not shown) is provided on the inlet side of the radiator 38. The water supply temperature sensor may detect the water temperature of the water supply source depending on the case, as long as it is in the inlet passage 32 and upstream of the radiator 38. However, in the case where the storage tank 42 is provided in the inlet passage 32, it is preferable that the water supply temperature sensor is provided in the inlet passage 32, at the storage tank 42 or downstream thereof, and upstream of the radiator 38. In addition, the heat recovery system 2 of the present embodiment is also provided with an outside air temperature sensor (not shown) so that the outside air temperature can be detected.

<<Operation of heat recovery system 2>>
Next, the operation of the heat recovery system 2 of this embodiment will be described. A series of controls described below are automatically performed by a controller (not shown). That is, the controller is connected to the pump 40, the radiator 38 (specifically, the motor of the fan 38A), the heat recovery valve 36 and the return valve 37, the hot water temperature sensor 43, the feed water temperature sensor, the outside air temperature sensor, and the like. The pump 40, the fan 38A, the valves 36 and 37, and the like are controlled based on the detection signals of the temperature sensors.

During operation of the compressor 3 (that is, during production of compressed air), the pump 40 is operated to pass the cooling water through the heat recovery heat exchanger 16. As a result, in the heat recovery heat exchanger 16, the discharge fluid (compressed air or additional water) from the compressor 3 can be cooled and the cooling water can be heated by the compression heat from the discharge fluid. The flow path of the hot water produced in this manner is switched by the switching means 35 according to the usage load of the hot water utilization section (whether there is a hot water request in the hot water utilization section at the end of the outlet passage 33). In other words, when hot water is needed in the hot water use unit, it is switched to the liquid passage, and when hot water is not needed in the hot water use unit, it is switched to the circulation route.

For example, hot water heated by the heat recovery heat exchanger 16 can be supplied to the water tank of the steam boiler via the outlet passage 33, and the liquid passage and the circulation path can be formed in accordance with the water level in the water tank. Can be switched. In that case, for example, when the water level in the water supply tank falls below the lower limit water level, hot water can be supplied as the liquid passage until the water level exceeds the upper limit water level. Then, when the water level in the water supply tank exceeds the upper limit water level, the circulation path may be switched to.

When the heat recovery system 2 is used for preheating the water supply to the water supply tank of the steam boiler (in other words, when the water supply to the water supply tank of the steam boiler is used as the cooling water), the inlet passage 32 is provided with a water softening device. Degassed softening water treated with a degasser (deoxidizer) is supplied. In this case, in the storage tank 42, it is preferable to float plastic beads all over the water surface of the storage tank 42 in order to prevent redissolution of oxygen.

In order to carry out the heat recovery (in other words, hot water discharge to the outside) while the cooling water is flowing through the heat recovery heat exchanger 16, the switching means 35 is switched to the liquid passage. In the liquid passage, the return valve 37 is closed and the heat recovery valve 36 is opened. Although details will be described later, the fan 38A is typically stopped. In this case, the water from the water supply source is heated by the heat recovery heat exchanger 16 and sent to the hot water utilization unit downstream of the outlet passage 33. At this time, if the opening degree of the heat recovery valve 36 is adjusted so that the temperature detected by the hot water temperature sensor 43 is maintained at the set temperature, the hot water at the set temperature can be supplied to the hot water utilization unit.

In order to stop the heat recovery (in other words, hot water discharge to the outside) while the cooling water is flowing through the heat recovery heat exchanger 16, the switching means 35 is switched to the circulation path. In the circulation path, the heat recovery valve 36 is closed while the return valve 37 is opened. Further, the fan 38A of the radiator 38 is operated. In this case, the cooling water heated by the heat recovery heat exchanger 16 is returned to the inlet path 32 via the return path 34, cooled by the radiator 38, and then supplied to the heat recovery heat exchanger 16 again. To be done. That is, while the cooling water is circulated through the heat recovery heat exchanger 16, the radiator 38 radiates heat to the outside air.

The fan 38A of the radiator 38 may be controlled as follows based on the temperature detected by the feed water temperature sensor and the temperature detected by the outside air temperature sensor while the cooling water is flowing through the liquid passage. That is, when the temperature detected by the feedwater temperature sensor is lower than the temperature detected by the outside air temperature sensor in the liquid passage, the fan 38A of the radiator 38 is operated. As a result, the radiator 38 can heat the cooling water by the outside air (that is, the radiator 38 can be used as a heater), and the cooling water to the heat recovery heat exchanger 16 can be preheated. On the other hand, when the temperature detected by the feed water temperature sensor is higher than the temperature detected by the outside air temperature sensor in the liquid passage, the fan 38A of the radiator 38 is stopped. This avoids the disadvantage that the radiator 38 cools the cooling water by the outside air.

By the way, in the present embodiment, as described above, the inlet passage 32 is provided with the cooling water storage tank 42 at the connection point of the return passage 34 or at the downstream thereof. In this case, during the heat recovery using the switching means 35 as the liquid passage, the storage tank 42 stores the cooling water having a relatively low temperature from the water supply source. Therefore, after that, when the heat recovery is stopped by using the switching unit 35 as the circulation path, first, the relatively low temperature cooling water in the storage tank 42 can be circulated to the heat recovery heat exchanger 16. Thereby, the temperature change of the cooling water at the time of switching by the switching unit 35 can be suppressed.

Next, a modification of the heat recovery system 2 of this embodiment will be described.
First, the installation position of the radiator 38 is not particularly limited as long as it is within the circulation path. For example, in the above-described embodiment, the radiator 38 is provided in the inlet passage 32 (the inlet passage 32 on the downstream side of the connection point with the return passage 34), but the radiator passage 38 (the connection point with the return passage 34 is provided. It may be provided in the upstream outlet path 33) or the return path 34. However, when the radiator 38 is provided in the inlet passage 32, as described above, the cooling water can be preheated in the liquid passage due to the relationship between the supply water temperature and the outside air temperature. On the other hand, when the radiator 38 is provided in the outlet passage 33 or the return passage 34, the fan 38A of the radiator 38 may be stopped in the liquid passage regardless of the water supply temperature or the outside air temperature. In that case, the installation of the feed water temperature sensor and the outside air temperature sensor can be omitted. It should be noted that regardless of the position of the radiator 38, the fan 38A of the radiator 38 is operated in the circulation path.

Further, the switching means 35 is not particularly limited as long as it can switch the flow of the cooling water between the liquid passage and the circulation passage. It may be composed of a three-way valve provided at the connection point between the inlet passage 32 and the return passage 34.

Further, in the above-described embodiment, the cooling water is passed through the aftercooler 5 and then through the water cooler 6, but in some cases, the cooling water may be passed through the water cooler 6 and then through the aftercooler 5. However, the passage through the aftercooler 5 first has the advantage that the compressed air can be surely cooled and the heated cooling water can be further heated by the water cooler 6.

Further, in the above-described embodiment, the cooling water is passed in series through the aftercooler 5 and the water cooler 6 as the heat recovery heat exchanger 16, but it may be passed in parallel in some cases. That is, downstream of the inlet passage 32, the cooling water may be bifurcated, one of which may be passed through the aftercooler 5 and the other of which may be passed through the water cooler 6, then merged and passed through the outlet passage 33.

Further, in the above embodiment, both the aftercooler 5 and the water cooler 6 are heat recovery heat exchangers 16, but only one of them may be the heat recovery heat exchanger 16 depending on the case. For example, only the aftercooler 5 may be used as the heat recovery heat exchanger 16, and the cooling water from the inlet passage 32 may be passed through the aftercooler 5 and led out from the outlet passage 33. In that case, the water cooler 6 may cool the separated water from the pre-separator 4 by another means (for example, ventilation by a fan). Conversely, only the water cooler 6 may be used as the heat recovery heat exchanger 16, and the cooling water from the inlet passage 32 may be passed through the water cooler 6 and led out from the outlet passage 33. In that case, aftercooler 5 may cool the compressed air from compressor 3 by other means (for example, ventilation by a fan).

Further, in the above embodiment, the opening degree of the heat recovery valve 36 is adjusted based on the temperature detected by the hot water temperature sensor 43 while the cooling water is flowing through the liquid flow path. May be controlled by an inverter to control the hot water temperature at a constant level. Alternatively, in some cases, the implementation of such a constant discharge temperature control may be omitted.

Further, although water is passed through the heat recovery heat exchanger 16 in the above embodiment, a liquid other than water may be passed as described above. That is, the heat recovery heat exchanger 16 is not limited to the water cooling type when cooling the compressed air or the added water, but may be a liquid cooling type using another liquid.

Further, when heat is recovered by the heat recovery heat exchanger 16 to produce hot water, water (cooling water) is passed through the heat recovery heat exchanger 16 in the above-described embodiment. Good. That is, for example, an antifreeze liquid such as ethylene glycol or water is circulated between the heat recovery heat exchanger 16 and another heat exchanger (hereinafter, referred to as a water flow heating heat exchanger), and the circulation liquid and the compression liquid are compressed. While exchanging heat in the heat recovery heat exchanger 16 and the like, heat is exchanged between the circulating liquid and the water flow in the water flow heating heat exchanger, and water is passed in the water flow heating heat exchanger. You may heat and produce warm water.

The air compression system 1 of the present invention is not limited to the configuration (including control) of the above-described embodiment (including modified examples), and can be appropriately changed. In particular, (a) a water-added compressor 3, (b) a pre-separator 4 for separating the discharge fluid from the compressor 3 into water and water, and (c) a pre-separator 4 to cool the compressed air after separation of water and water. After-cooler 5 to be operated, (d) Water cooler 6 for cooling the separated water after the water-water separation by pre-separator 4, (e) Compressed air and separated water after passing through each cooler 5, 6 are supplied, Other configurations are not particularly limited as long as the compressed air delivery passage 17 is connected to the vapor phase portion and the separator tank 7 to which the added water return passage 11 to the compressor 3 is connected is provided in the liquid phase portion. ..

For example, in the above embodiment, the aftercooler 5 and the water cooler 6 are configured to recover heat, but this is not essential. That is, as long as the aftercooler 5 can cool the compressed air, the aftercooler 5 may be, for example, of an air cooling type (cooling by a fan) regardless of its configuration. Similarly, the water cooler 6 may be of an air cooling type (cooling by a fan), for example, regardless of its configuration, as long as it can cool the separated water.

Alternatively, the aftercooler 5 and/or the water cooler 6 may be liquid-cooled (typically water-cooled), or may circulate the liquid with a liquid cooling device such as a cooling tower or a chiller. Good. In other words, the cooling water may be circulated between the aftercooler 5 or the water cooler 6 and the radiator 38 in the above-described embodiment. On the contrary, in the above embodiment, the return passage 34 may be omitted, and only the liquid passage may be provided.

The heat recovery system 2 associated with the air compression system 1 of the present invention can be suitably used for applications other than the feed water preheating of the steam boiler illustrated in the above-mentioned embodiment. For example, hot water produced by the heat recovery system 2 may be used for air conditioning in factories or business establishments, or may be used for heat retention or cleaning in various manufacturing processes.

1 Air compression system 2 Heat recovery system 3 Compressor 4 Pre-separator 5 After cooler 6 Water cooler 7 Separator tank 8 Motor 9 Air filter 10 Suction path 11 Added water return path 12 Discharge path 13 Check valve 14 Gas phase communication path 15 Liquid phase Communication passage 16 Heat recovery heat exchanger 17 Compressed air delivery passage 18 Primary pressure regulating valve 19 Check valve 20 Safety valve 21 Exhaust valve 22 Addition water valve 23 Water filter 24 Water supply passage (24A: first water supply passage, 24B: first) (Two water channels)
25 drainage channel 26 first water supply valve 27 check valve 28 second water supply valve 29 drainage valve 30 water level detector 31 pressure sensor 32 inlet channel 33 outlet channel 34 return channel 35 switching means 36 heat recovery valve 37 return valve 38 radiator (38A :fan)
39 Communication path 40 Pump 41 Check valve 42 Storage tank 43 Hot water temperature sensor

Claims (5)

Water is added to the intake air, and a water-added compressor that seals the compression chamber and cools and lubricates the compression mechanism with this added water ,
Accept the fluid discharged from the compressor, and the pre-separator steam separator to the discharge fluid in the added water and the compressed air,
The pre-separator separately receives the compressed air and the added water after the separation of water and, while separating the compressed air into water and water, a separator tank for storing the added water , and
The gas phase part of the pre-separator is connected to the gas phase part of the separator tank via a gas phase communication passage,
The liquid phase part of the pre-separator is connected to the liquid phase part of the separator tank via a liquid phase communication passage,
A compressed air delivery passage is connected to the vapor phase portion of the separator tank,
The liquid phase portion of the separator tank is connected to a return path of added water to the compressor,
The gas phase communication passage is provided with an aftercooler for cooling compressed air,
The liquid compression passage is provided with a water cooler for cooling the added water . A water supply passage connected to the air suction passage to the compressor and provided with a water supply valve,
A drainage channel connected to the bottom of the separator tank and provided with a drainage valve,
A water level detector provided in the separator tank,
A controller that controls the water supply valve and the drain valve according to the detected water level of the water level detector.
The air compression system according to claim 1, wherein: The aftercooler is a heat exchanger of compressed air and cooling water flowing through the gas phase communication passage ,
The water cooler is a heat exchanger for adding water and cooling water flowing through the liquid phase communication passage ,
The air compression system according to claim 1 or 2 , wherein warm water is produced by heating the cooling water in each of the coolers. The air cooling system according to claim 3 , wherein the cooling water is passed through the aftercooler and then through the water cooler. Wherein the delivery path, the air compression system according to any one of claims 1 to 4, characterized in that the primary pressure adjusting valve to hold the separator tank above the set pressure is provided.

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