JP2011226467A - Compression heat recovery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve hot water at a desired temperature by recovering the compression heat of a compressor.SOLUTION: An air cooler 5 is a heat exchanger between compressed air delivered from the compressor 5 and the cooling water. An oil cooler 6 is a heat exchanger between lubricating oil of the compressor 4 and the cooling water. A heat exchange water supply pump 17 is controlled by an inverter to adjust the quantity of water to be supplied to the air cooler 5 and the oil cooler 6 based on a temperature of the cooling water after passing through the air cooler 5 and the oil cooler 6, and thereby, the hot water at the desired temperature can be obtained.

Description

  The present invention relates to a compression heat recovery system for an air compressor.

  In Patent Document 1 below, compressed water is supplied to the water supply tank of the boiler to cool the compressed air and the lubricating oil of the compressor, thereby heating the water supplied to the water supply tank. Is disclosed. Specifically, water is supplied to a boiler water supply tank via an air cooler and an oil cooler, and the air cooler cools compressed air, while the oil cooler cools the lubricating oil of the compressor. The water supply to the water supply tank is heated at.

JP 2010-38385 A

  However, the amount of water supplied to the water supply tank is adjusted so that the lubricating oil passed through the oil cooler is maintained at a predetermined temperature. Therefore, since the water temperature after passing through each cooler fluctuates, it may be difficult to use for purposes other than water supply to the boiler. Further, depending on the load of the compressor, the water after passing through each cooler exceeds 100 ° C., requiring high-temperature specification piping or vaporizing.

  The problem to be solved by the present invention is to suppress the fluctuation of the water temperature after passing through the air cooler or the oil cooler and obtain hot water having a desired temperature even if the load of the compressor fluctuates. It is another object of the present invention to provide a compressed heat recovery system that can be used for applications other than water supply to a boiler.

  The present invention has been made to solve the above problems, and the invention according to claim 1 is directed to an air cooler for exchanging heat between compressed air discharged from the compressor and its cooling water, and lubrication of the compressor. An oil cooler for exchanging heat between the oil and its cooling water, and a heat supply water amount adjusting means for adjusting the flow rate of the cooling water supplied to each cooler based on the temperature of the cooling water after passing through each of the coolers. It is a compression heat recovery system characterized by comprising.

  According to the first aspect of the present invention, since the amount of water supplied to each cooler is adjusted based on the water temperature after passing through each cooler, it is possible to suppress fluctuations in the water temperature even if there is a load fluctuation of the compressor. it can. Moreover, since the water temperature of desired temperature can be obtained, it is easy to utilize also for uses other than the water supply to a boiler.

  According to a second aspect of the present invention, an oil feed path for sending lubricating oil from the compressor to the oil cooler and an oil return path for returning lubricating oil from the oil cooler to the compressor are connected by a bypass path, A temperature-controlled three-way valve is provided at the junction between the oil feed path and the bypass path, or at the junction between the oil return path and the bypass path, and the flow rate of lubricating oil passed through the oil cooler by the temperature-controlled three-way valve The compression heat recovery system according to claim 1, wherein the lubricating oil in the compressor is maintained at a set temperature by adjusting

  According to the second aspect of the present invention, the lubricating oil of the compressor can be maintained at a desired temperature by adjusting the flow rate of the lubricating oil that is passed through the oil cooler by the temperature control three-way valve.

  According to a third aspect of the present invention, the cooling water is passed through the two coolers arranged in series, and based on the temperature of the cooling water after passing through the two coolers, the heat exchange provided in the water supply passages to the two coolers. 3. The compression heat recovery system according to claim 2, wherein the feed water pump is controlled by an inverter, or the opening degree of the motor-operated valve provided in the water supply path to both the coolers is adjusted.

  According to the third aspect of the present invention, the air cooler and the oil cooler are connected in series, and the heat exchange water pump is inverter-controlled, or the opening degree of the motor-operated valve provided in the water supply passage is adjusted. With such a configuration, the water temperature after passing through each cooler can be maintained as desired.

  According to a fourth aspect of the present invention, the compressor is driven by a screw-type steam engine that generates power using steam, and the cooling water heated by the both coolers is supplied to a shaft seal portion of the screw-type steam engine. 4. The method according to claim 3, wherein further heating is performed with steam leaking from the refrigerant, and the heat exchange water pump is inverter-controlled or the opening of the motor-operated valve is adjusted based on the temperature of the cooling water after the heating. It is a compression heat recovery system of description.

  According to the fourth aspect of the present invention, it is possible to recover heat from the shaft leakage steam of the screw steam engine.

  According to a fifth aspect of the present invention, when the compression heat recovery system is started up, cooling water is allowed to flow through each of the coolers at a set flow rate until the first set condition is satisfied. The compressed heat recovery system according to any one of claims 1 to 4, wherein the amount of water flow to each cooler is adjusted based on the temperature of the cooling water after being passed.

  According to the fifth aspect of the present invention, it is possible to prevent a delay in detection of a rise in water temperature by forcibly passing water through each cooler when the compression heat recovery system is activated. Thereby, desired cooling of compressed air and lubricating oil can be aimed at. Furthermore, since the water flow rate is limited to the set flow rate, it is possible to prevent the cooling water from being sent unnecessarily.

  According to a sixth aspect of the present invention, the amount of water passing through each of the coolers until the first setting condition is satisfied is set so as to increase as the temperature of the cooling water after passing through each of the coolers increases. The compression heat recovery system according to claim 5.

  According to the sixth aspect of the invention, the amount of water flow is increased as the water temperature rises, so that the desired cooling of the compressed air and the lubricating oil can be achieved.

  Further, in the invention according to claim 7, when the compression heat recovery system is stopped, the cooling water is allowed to flow to each of the coolers at a set flow rate until the second set condition is satisfied. The compressed heat recovery system according to any one of claims 1 to 6, wherein water flow to each cooler is stopped.

  According to the seventh aspect of the present invention, the forced cooling of the compressed air and the lubricating oil can be achieved by forcibly passing water through each cooler when the compression heat recovery system is stopped. Furthermore, since the water flow rate is limited to the set flow rate, it is possible to prevent the cooling water from being sent unnecessarily.

  ADVANTAGE OF THE INVENTION According to this invention, even if the load of a compressor is fluctuate | varied, the fluctuation | variation of the water temperature after passing an air cooler or an oil cooler can be suppressed, and hot water of desired temperature can be obtained. Moreover, the compression heat recovery system which can respond also to uses other than the water supply to a boiler is realizable.

It is the schematic which shows one Example of the compression heat recovery system of this invention. It is the schematic which shows the modification of the compression heat recovery system of FIG.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing an embodiment of the compression heat recovery system of the present invention. The compression heat recovery system 1 of the present embodiment uses the water supplied to the water supply tank 3 of the boiler 2 to cool the compressed air and the lubricating oil of the compressor 4, thereby supplying water to the water supply tank 3. This system recovers compression heat by heating. Therefore, the compression heat recovery system 1 of the present embodiment includes a compressor 4, an air cooler 5, and an oil cooler 6 as main parts.

  The configuration of the compressor 4 is not particularly limited. In the present embodiment, the compressor 4 is an oil-lubricated and screw-type air compressor. Compressed air discharged from the compressor 4 is cooled to a desired temperature in the air cooler 5 and then sent to various types of compressed air utilization equipment (not shown). On the other hand, the lubricating oil of the compressor 4 circulates between the oil cooler 6 and is water-cooled to a desired temperature.

  In this embodiment, the compressor 4 is driven by a steam engine 7. The steam engine 7 is a device that generates power using steam. The configuration of the steam engine 7 is not particularly limited, but is a screw-type steam engine in the present embodiment. A screw-type steam engine is an apparatus in which steam is introduced between screw rotors that mesh with each other, and the steam is expanded and decompressed while rotating the screw rotor by the steam, and power is obtained by rotation of the screw rotor at that time.

  Steam is supplied to the steam engine 7 through the steam supply path 8, and the steam is discharged through the exhaust steam path 9. By adjusting the opening / closing or opening degree of the steam supply valve 10 provided in the steam supply path 8, the presence or absence of the operation of the steam engine 7 or the output can be adjusted. In the present embodiment, as described above, the compressor 4 is driven by the steam engine 7, but may be auxiliary driven by an electric motor (not shown). Alternatively, the compressor 4 may be driven by an electric motor by installing an electric motor instead of the steam engine 7 in FIG. Note that the compressor 4, the steam engine 7, the air cooler 5, and the oil cooler 6 may be configured as a unit 11 as shown by a one-dot chain line in FIG.

  The air cooler 5 is an indirect heat exchanger between compressed air and its cooling water. Specifically, the compressed air discharged from the compressor 4 is sent to the air cooler 5 through an oil separator (not shown), water-cooled in the air cooler 5, and then moisture-removed by an air dryer (not shown). And sent to a compressed air utilization device (not shown).

  The oil cooler 6 is an indirect heat exchanger between the lubricating oil of the compressor 4 and its cooling water. Specifically, the compressor 4 and the oil cooler 6 are connected by an oil feed path 12 and an oil return path 13. As a result, the lubricating oil of the compressor 4 (in the case of an oil-lubricated compressor as in the present embodiment, more precisely, the lubricating oil separated from the compressed air by the oil separator) passes through the oil feed path 12. After being sent to the oil cooler 6 and water-cooled in the oil cooler 6, it is returned to the main body of the compressor 4 through the oil return path 13.

  In this embodiment, the oil feed path 12 and the oil return path 13 are connected by a bypass path 14. A temperature-controlled three-way valve 15 is provided at a branch portion between the oil feed path 12 and the bypass path 14. The temperature control three-way valve 15 is preferably a wax type, and the lubricant oil is sent to the oil cooler 6 based on the temperature of the lubricant oil from the compressor 4, or the bypass passage 14 without passing through the oil cooler 6. The distribution ratio to be returned to the compressor 4 via is adjusted by itself. Thereby, the flow volume of the lubricating oil passed through the oil cooler 6 can be adjusted, and the lubricating oil in the compressor 4 can be maintained at a desired temperature.

  The air cooler 5 and the oil cooler 6 are sequentially provided in the middle of the water supply path 16 to the water supply tank 3. In other words, the air cooler 5 and the oil cooler 6 are provided in series in the water supply path 16 to the water supply tank 3. Therefore, the water supply to the water supply tank 3 is supplied to the water supply tank 3 of the boiler 2 through the air cooler 5 and the oil cooler 6 in order. In addition, since the water supply to the water supply tank 3 turns into water supply to the boiler 2, the deaerated soft water is used suitably.

  The amount of water supplied to the water supply tank 3 via each of the coolers 5 and 6 can be changed by an inverter pump as heat exchange water amount adjustment means. Specifically, a heat exchange water pump 17 is provided in the water supply passage 16 to the water supply tank 3 on the upstream side of the coolers 5 and 6, and the heat exchange water pump 17 is rotated by an inverter 18. The amount of water supplied to each of the coolers 5 and 6 is adjusted by changing the rotation speed.

  This amount of water supply is adjusted based on the water temperature after passing through both coolers 5 and 6. Specifically, a temperature sensor 19 is provided downstream of the oil cooler 6 in the water supply path 16 to the water supply tank 3, and the heat exchange water pump 17 is inverter-controlled based on a detection signal of the temperature sensor 19. Thus, the amount of water supply is adjusted. If the amount of water supplied by the heat exchange water supply pump 17 is adjusted so that the temperature detected by the temperature sensor 19 is maintained at the set temperature, hot water having a desired temperature can be obtained.

  The water supply tank 3 can be supplied with water through the replenishment water channel 20 in addition to the water supplied through the coolers 5 and 6. Considering that this water is also supplied to the boiler 2, degassed soft water is preferably used. A replenishment water valve 21 is provided in the replenishment water channel 20, and the presence or absence of water supply to the water supply tank 3 is switched by opening and closing the replenishment water valve 21.

  Although there is a possibility that the amount of water in the water supply tank 3 cannot be secured as desired depending on the load of the compressor 4 only by water supply through the coolers 5 and 6, in that case, the water supply tank 3 directly through the replenishment water channel 20. Water is supplied. Specifically, a water level detector 22 is provided in the water supply tank 3, and the water level in the water supply tank 3 is set within a set range by controlling the makeup water valve 21 based on a detection signal from the water level detector 22. Maintained. In addition, the water supply tank 3 is also provided with an overflow path 23 for overflowing a predetermined amount of water to the outside.

  The stored water in the water supply tank 3 is supplied to the boiler 2 through a water supply pump 24 and a check valve 25 as required. The water is vaporized in the boiler 2, and the steam from the boiler 2 is sent to various steam utilizing devices such as the steam engine 7.

  In the compression heat recovery system 1 of this embodiment, the water supplied to the water supply tank 3 is supplied to the water supply tank 3 after cooling the compressed air in the air cooler 5 and cooling the lubricating oil in the oil cooler 6. . At this time, the water supplied to the water supply tank 3 is heated by collecting the compression heat in the air cooler 5 and the oil cooler 6. In this way, cooling of the lubricating oil and compressed air of the compressor 4 can be achieved by supplying water to the water supply tank 3, and heating of the water supplied to the water supply tank 3 can be achieved in both coolers 5 and 6. Furthermore, in the compression heat recovery system 1 of the present embodiment, the heat exchange water pump 17 can be inverter-controlled so that the water temperature after passing through each of the coolers 5 and 6 is maintained at a set temperature (for example, 80 ° C.), Thereby, hot water at a desired temperature can be obtained. Moreover, the cooling of the lubricating oil in the compressor 4 is automatically adjusted by the temperature control three-way valve 15.

  The compression heat recovery system 1 of the present invention is not limited to the configuration of the above embodiment, and can be changed as appropriate. In particular, as long as the air cooler 5 and the oil cooler 6 are provided and the amount of water supplied to each of the coolers 5 and 6 is adjusted based on the water temperature after passing through the coolers 5 and 6, other configurations and controls are appropriately set. Can be changed. For example, in the above embodiment, the compressor 4 is driven by the steam engine 7, but the present invention can be similarly applied to the compressor 4 driven by an electric motor.

  Moreover, in the said Example, although the warmed water after passing each cooler 5 and 6 was used as feed water to the boiler 2, it is applicable also to uses other than boiler feed water, such as an air conditioner and a food machine. is there. Since the temperature of the obtained warm water can be maintained as desired, it can be applied to a wide range of uses.

  Moreover, in the said Example, although the air cooler 5 and the oil cooler 6 were provided in order in the water supply path 16, this installation order may be reversed depending on the case. Moreover, in the said Example, although the air cooler 5 and the oil cooler 6 were provided in series in the water supply path 16, you may provide in parallel depending on the case. Even in this case, the water after passing through the coolers 5 and 6 may be merged, and the amount of water supplied to the coolers 5 and 6 may be adjusted based on the water temperature. In this case, the amount of water supplied to each of the coolers 5 and 6 may be individually adjustable.

  In the embodiment, the compressor 4 may have a plurality of stages. For example, when the compressor 4 has two stages, the compressed air from the first stage compressor 4 is cooled by the first air cooler (intercooler) 5 and then further cooled by the second stage compressor 4. Compressed and water-cooled by a second air cooler (aftercooler) 5. And these two air coolers 5 and 5 and the oil cooler 6 may be installed in series in the water supply path 16, and two or all of them may be installed in parallel. In any case, the installation order can be changed as appropriate. For example, the cooling water is passed through the oil cooler 6, the aftercooler (5), and the intercooler (5) in this order.

  Similarly, the compressor 4 is not limited to the oil lubrication type but may be a non-lubricating type (oil-free type). That is, even in the case of the non-lubricated compressor 4, the compressed air from the first stage compressor 4 is cooled by the first air cooler (intercooler) 5 and then the second stage compressor 4. It is further compressed and water-cooled by a second air cooler (aftercooler) 5. In the case of a non-lubricated compressor, there is no lubricating oil in the compressor body, but there is lubricating oil in the gear portion, and this lubricating oil is cooled by the oil cooler 6 as in the above embodiment. Can do.

  Moreover, in the said Example, as shown with the dashed-two dotted line of FIG. 1, you may further heat the water supply to the water supply tank 3 with the axial leak steam from the screw-type steam engine 7. FIG. Specifically, another heat exchanger 26 is provided in the water supply path 16 to the water supply tank 3 downstream from the oil cooler 6. The heat exchanger 26 is supplied with water supplied to the water supply tank 3 and is also supplied with shaft leakage steam from the steam engine 7. Thereby, the water supply to the water supply tank 3 can be further heated. In this case, the amount of water supplied to each of the coolers 5, 6 and 26 may be adjusted based on the water temperature after passing through the heat exchanger 26. Thereby, it can respond also to the increase / decrease in axial leakage steam.

  Moreover, in the said Example, although the temperature control three-way valve 15 was provided in the branch part of the oil feed path 12 and the bypass path 14, in the junction part of the oil return path 13 and the bypass path 14, as shown in FIG. A temperature-controlled three-way valve 15 may be provided. Also in this case, the temperature control three-way valve 15 sends the lubricating oil to the oil cooler 6 based on the temperature of the lubricating oil from the compressor 4 or passes through the bypass passage 14 to the compressor 4 without passing through the oil cooler 6. Adjust the return distribution ratio by yourself. Thereby, the flow volume of the lubricating oil passed through the oil cooler 6 can be adjusted, and the lubricating oil in the compressor 4 can be maintained at a desired temperature.

  Further, in the above embodiment, the heat exchange water pump 17 is inverter-controlled as the heat exchange water supply amount adjusting means. However, as shown in FIG. 2, the heat exchange water pump 17 and the electric valve 27 are connected in series to the water supply path 16. May be provided. In this case, the heat supply water pump 17 is on / off controlled, and the opening of the motor operated valve 27 is adjusted based on the detection signal of the temperature sensor 19. 2 is different from FIG. 1 in the configuration of the heat supply water amount adjusting means and the installation position of the temperature control three-way valve 15, but the configuration of the heat supply water amount adjustment means and the installation position of the temperature control three-way valve 15 are different. Of course, only one of them may be different from that shown in FIG.

  By the way, as described above, the compression heat recovery system 1 controls the amount of water flow to both the coolers 5 and 6 based on the temperature detected by the temperature sensor 19, but when the compression heat recovery system 1 starts cold, the water temperature rises. There will be some delay before detection. Therefore, if the water flow amount control by the temperature sensor 19 is performed immediately after activation, the actual water flow may be delayed and the temperature of the compressed air or lubricating oil may increase. Therefore, when the compression heat recovery system 1 is started, it is preferable to forcibly pass the cooling water at the set flow rate to each of the coolers 5 and 6 until the first setting condition is satisfied.

  For example, the heat exchange water pump 17 sends out a small flow rate until a predetermined time elapses from the start signal or the temperature detected by the temperature sensor 19 rises to a predetermined temperature (FIG. 1), or the motorized valve 27 is set to a set opening degree ( (Typically, the minimum opening) only needs to be opened (FIG. 2). And after satisfy | filling 1st setting conditions, what is necessary is just to switch to the water flow control by the temperature sensor 19. FIG.

  Note that the water flow amount to each of the coolers 5 and 6 until the first setting condition is satisfied may be increased as the temperature detected by the temperature sensor 19 increases. That is, as the temperature detected by the temperature sensor 19 rises, the amount of water sent out by the heat exchange water pump 17 is gradually increased (FIG. 1), or the opening degree of the motor-operated valve 27 may be gradually increased (FIG. 2).

  By forcibly passing water through the coolers 5 and 6 at the time of startup in this way, detection delay by the temperature sensor 19 can be prevented. Thereby, the excessive temperature rise of compressed air or lubricating oil can be prevented. Further, by limiting the amount of water flow, there is no possibility that low-temperature water is supplied to the water supply tank 3 wastefully.

  Conversely, if the water flow to each of the coolers 5 and 6 is stopped immediately when the compression heat recovery system 1 is stopped, the compression heat may not be recovered to the end. In particular, even if the steam supply valve 10 to the steam engine 7 is closed, steam remains in the steam engine 7, so that even if it is recovered by the heat exchanger 26, it passes through the coolers 5 and 6. I need water. Therefore, when the compression heat recovery system 1 is stopped, it is preferable to forcibly supply the cooling water to each of the coolers 5 and 6 at a set flow rate until the second setting condition is satisfied.

  For example, a small flow rate is sent out by the heat exchange water pump 17 until a predetermined time elapses from the stop signal or the temperature detected by the temperature sensor 19 falls to a predetermined temperature (FIG. 1), or the motorized valve 27 is set to a set opening (typical In other words, it is only necessary to open only the minimum opening (FIG. 2). And after satisfy | filling 2nd setting conditions, what is necessary is just to stop the water flow to each cooler 5 and 6 completely.

  By forcibly passing water through each of the coolers 5 and 6 at the time of stopping as described above, it is possible to cool the lubricating oil of the compressor 4 and recover heat from the steam remaining in the steam engine 7.

DESCRIPTION OF SYMBOLS 1 Compression heat recovery system 3 Water supply tank 4 Compressor 5 Air cooler 6 Oil cooler 7 Steam engine 12 Oil feed path 13 Oil return path 14 Bypass path 15 Temperature control three-way valve 16 Water supply path 17 Heat exchange water pump 18 Inverter 19 Temperature sensor 26 Heat Exchanger 27 Electric valve

Claims (7)

An air cooler for exchanging heat between the compressed air discharged from the compressor and its cooling water;
An oil cooler for exchanging heat between the lubricating oil of the compressor and its cooling water;
And a heat supply water amount adjusting means for adjusting a flow rate of the cooling water supplied to each of the coolers based on a temperature of the cooling water after passing through each of the coolers. An oil feed path for sending lubricating oil from the compressor to the oil cooler and an oil return path for returning the lubricating oil from the oil cooler to the compressor are connected by a bypass path,
A temperature control three-way valve is provided at the junction between the oil feed path and the bypass path, or the junction between the oil return path and the bypass path,
2. The compression heat recovery system according to claim 1, wherein the temperature of the lubricating oil passing through the oil cooler is adjusted by the temperature control three-way valve to maintain the lubricating oil in the compressor at a set temperature. Cooling water is passed through both the coolers arranged in series,
Based on the temperature of the cooling water after passing through both coolers, the inverter of the heat exchange water pump provided in the water supply passages to the both coolers is controlled by the inverter, or the opening degree of the motor operated valve provided in the water supply passages to the both coolers It adjusts. The compression heat recovery system of Claim 2 characterized by the above-mentioned. The compressor is driven by a screw-type steam engine that generates power using steam,
The cooling water heated by the both coolers is further heated by steam leaking from the shaft seal portion of the screw steam engine,
The compression heat recovery system according to claim 3, wherein the heat exchange water pump is inverter-controlled or the opening degree of the motor-operated valve is adjusted based on the temperature of the cooling water after heating. When starting the compression heat recovery system, until the first setting condition is satisfied, the cooling water is allowed to flow at a set flow rate to each of the coolers.
When the first setting condition is satisfied, the amount of water flow to each cooler is adjusted based on the temperature of the cooling water after being passed through each cooler. The compression heat recovery system described in 1. The amount of water flow to each of the coolers until the first setting condition is satisfied is set so as to increase with an increase in temperature of the cooling water after passing through each of the coolers. Compression heat recovery system. When the compression heat recovery system is stopped, the cooling water is allowed to flow to each of the coolers at a set flow rate until the second setting condition is satisfied.
The compressed heat recovery system according to any one of claims 1 to 6, wherein when the second setting condition is satisfied, water flow to each of the coolers is stopped.

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