Water cooling system and air separation device provided with same

Abstract

The invention provides a water cooling system, in a system provided with a dry type water cooler and a wet type water cooler, condensed water is generated through a compressed air cooler, and the condensed water is supplied to the wet type water cooler, so that make-up water is inhibited. A water cooling system (A1) is provided with: a compressed air cooler (12) for cooling compressed air; a wet water cooler (13) into which the condensed water generated in the compressed air cooler (12) is introduced as make-up water; a cooling water pump (14) for conveying compressed air to the cold end of the compressed air cooler (12) in order to cool the compressed air by cooling water led out from the wet water cooler (13); a dry water cooler (14) for cooling warm water led out from the warm end of the compressed air cooler (12); and a first flow rate adjustment valve (121) for adjusting the flow rate of the condensed water.

Description

Technical Field

[0001] The present invention relates to a water cooling system, and in particular to a water cooling system for cooling cooling water used in an air compressor. Background Art

[0002] Cooling water used for cooling equipment is generally cooled by a wet water cooler and a dry water cooler (for example, refer to Reference 1).

[0003] A wet water cooler is a water cooler that evaporates part of the cooling water and cools the cooling water by the latent heat, and has a structure open to the atmosphere or a structure isolated from the atmosphere and operated under reduced pressure (for example, see Reference 2). However, the cooling water lost due to evaporation needs to be replenished.

[0004] There are two types of configurations in which the makeup water is mixed with cooling water, and another type in which the makeup water is not mixed with cooling water but is indirectly cooled via a heat exchanger. However, the evaporation loss of water is a common problem in either configuration. In addition, when the makeup water and cooling water are mixed, there is also the problem of concentration of mineral components contained in the water.

[0005] A dry water cooler is a water cooler that cools cooling water by heat exchange with the air, and in order to improve the efficiency of the heat exchange, it is necessary to use a blower or the like (for example, refer to Reference 3).

[0006] In view of the availability of water resources and electricity, it is known to combine wet water coolers and dry water coolers to optimize the water cooling system, but in any case, a supply of make-up water is required to operate the wet cooler.

[0007] In particular, in today's world where the supply of both water resources and electricity is tight, it is required to build a system that optimizes the use of water and electricity according to environmental conditions without adding equipment that needs cooling. This demand is particularly significant in air separation devices equipped with air compressors. This is because the temperature difference between the cooling water of the air compressor and the atmosphere is usually small. In the case of atmospheric cooling, the air supply volume increases and the load of the blower becomes larger. Therefore, it is economically reasonable to use the latent heat of evaporation of water to cool the water to reduce the power consumption of the blower.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Utility Model Application Laid-Open No. 51-056644

[0011] Patent Document 2: Japanese Patent Application Publication No. 2004-232925

[0012] Patent Document 3: U.S. Patent Publication No. 2021 / 0341222A1 Summary of the invention

[0013] Problems to be solved by the invention

[0014] In view of the above problems and needs, the present disclosure provides a water cooling system including a dry water cooler and a wet water cooler, wherein condensed water is generated by a compressed gas cooler and supplied to the wet water cooler, thereby suppressing makeup water.

[0015] In addition, an air separation device including the water cooling system is provided.

[0016] Technical solutions to solve problems

[0017] The water cooling system disclosed in the present invention comprises:

[0018] A compressed gas cooler cools the compressed gas compressed by the compressor that takes in the gas to be processed;

[0019] a wet water cooler, which introduces condensed water produced in the compressed gas cooler as makeup water;

[0020] a cooling water pump for delivering cooling water led out of the wet water cooler to a cold end of the compressed gas cooler in order to cool the compressed gas;

[0021] a dry water cooler for cooling the cooling water derived from the warm end of the compressed gas cooler;

[0022] a first condensate line pipe for conveying condensate derived from the compressed gas cooler; and

[0023] The first flow regulating valve is provided on the first condensate line pipe and regulates the flow of the condensate.

[0024] Examples of the gas to be processed include air (atmosphere), liquefied natural gas (LNG), natural gas (NG), boil-off gas, and the like.

[0025] Examples of the compressed gas include compressed air, compressed natural gas, and compressed boil-off gas.

[0026] The water cooling system (A1, A2, A3) of the present disclosure may also include:

[0027] A compressed air cooler (12) cools compressed air compressed by an air compressor (11) taken into the atmosphere;

[0028] A wet water cooler (13) that introduces condensed water produced in the compressed air cooler (12) as makeup water;

[0029] a cooling water pump (14) for cooling the compressed air by cooling water led out from the wet water cooler (13) and delivering the compressed air to the cold end of the compressed air cooler (12);

[0030] A dry water cooler (15) cools the warm water (cooling water after heat exchange) discharged from the warm end of the compressed air cooler (12);

[0031] a first condensate line pipe (L2) for conveying condensate derived from the compressed air cooler (12) (to the wet water cooler (13)); and

[0032] The first flow regulating valve (121) is provided in the first condensate line pipe (L2) to regulate the flow of condensate.

[0033] The water cooling system (A1, A2, A3) disclosed herein may also include a cooling water line piping (L3), which transports the cooling water derived from the wet water cooler (13) to the cold end of the compressed air cooler (12), and from the warm end of the compressed air cooler (12) to the dry water cooler (15), and transports the derived cooling water to the wet water cooler (13).

[0034] The water cooling system (A1, A2, A3) may also include an atmospheric line piping (L1), wherein the atmospheric line piping (L1) conveys the atmospheric air to the air compressor (11), and conveys compressed air from the air compressor (11) to the compressed air cooler (12).

[0035] The compressed air (saturated with water vapor) discharged from the compressed air cooler (12) may be supplied to an air separation device.

[0036] The water cooling system (A1, A2, A3) may also include one or more of a storage portion (12a) of a compressed air cooler (12) or a separately provided buffer for storing the condensate, a storage portion (131) of a wet water cooler (13) or a separately provided buffer, and a storage portion (161) of a water buffer (16) provided in a condensate line piping (L2).

[0037] The water cooling system (A1) may also include:

[0038] A second condensate line pipe (L21) for conveying condensate from the water buffer (16) to the wet water cooler (13); and

[0039] The second flow regulating valve (122) is provided in the second condensate line pipe (L21) to regulate the flow of condensate.

[0040] The water cooling system (A2) may also include a first control unit (18), wherein the first control unit (18) controls the first flow regulating valve (121) and / or the second flow regulating valve (122) to control the supply amount of condensed water.

[0041] The water cooling system (A1) may also include:

[0042] a first level gauge (22) for measuring the amount of cooling water in the cooling water storage portion (131) of the wet water cooler (13); and

[0043] The second level gauge (21) measures the amount of water in the storage portion (161) of the water buffer (16).

[0044] The first control unit (18) may also control the driving of the cooling water pump (14).

[0045] The water cooling system (A3) may include a second control unit (19) for controlling the operation rate of the dry water cooler (15) (controlling a blower) according to an increase or decrease in electricity cost.

[0046] The second control unit (19) may control the second flow rate regulating valve (122) based on the data of the first level meter (22) and the data of the second level meter (21).

[0047] The second control unit (19) may also control the driving of the cooling water pump (14).

[0048] The air separation device of the present disclosure may include the water cooling system (A1, A2, A3). BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a diagram showing the water cooling system according to the first embodiment.

[0050] Figure 2 This is a diagram showing a water cooling system according to the second embodiment.

[0051] Figure 3 This is a diagram showing a water cooling system according to a third embodiment.

[0052] Figure 4 This is a diagram showing a water cooling system (parallel arrangement) according to another embodiment of the first embodiment.

[0053] Description of Reference Numerals

[0054] 11 air compressor; 12 compressed air cooler; 13 wet water cooler; 15 dry water cooler. DETAILED DESCRIPTION

[0055] Several embodiments of the present disclosure are described below. The embodiments described below illustrate an example of the present disclosure. The present disclosure is not limited by the following embodiments, and also includes various deformation methods implemented within the scope of the gist of the present disclosure. In addition, all the structures described below are not necessarily required structures of the present disclosure. Upstream and downstream are based on the flow direction of the airflow.

[0056] (Implementation Method 1)

[0057] use Figure 1 The water cooling system A1 according to the first embodiment will be described.

[0058] The water cooling system A1 includes a compressed air cooler 12 , a wet water cooler 13 , a cooling water pump 14 , and a dry water cooler 15 .

[0059] The compressed air cooler 12 cools the compressed air compressed by the air compressor 11 that takes in the atmosphere. The compressed air cooler 12 has a condensate storage section 12a at the bottom that stores condensed water. The compressed air compressed by the air compressor 11 is dried to a state saturated with water vapor by cooling water, thereby generating condensed water. The cooling water is transported from the storage section 131 of the wet water cooler 13 by the cooling water pump 14. The compressed air cooler 12 produces compressed air saturated with water vapor by exchanging heat between the atmosphere compressed by the air compressor 11 and the cooling water. The water condensed by cooling condenses on the surface of the heat exchanger and drips, or the mist or droplet-shaped condensed water floating in the compressed air is separated by a moisture separator (demister) and the like, and stored in the compressed air cooler 12.

[0060] The wet water cooler 13 has a storage portion 131, and the condensed water generated in the compressed air cooler 12 is introduced as the makeup water through the first condensed water line pipe L2. The wet water cooler 13 evaporates a part of the cooling water, and cools the cooling water by the latent heat of evaporation. In the present embodiment, although the water is evaporated by contact with the atmosphere (natural convection or forced convection), it is also possible to evaporate under reduced pressure conditions isolated from the atmosphere without opening to the atmosphere, and the cooling water can also be indirectly cooled by a heat exchanger cooled by the evaporation of water.

[0061] The first condensate line pipe L2 is provided with a flow regulating valve 121 , and the condensate can be transported from the compressed air cooler 12 to the wet water cooler 13 by controlling the valve opening and closing.

[0062] For example, the flow regulating valve 121 can be opened and closed by timer control, can be opened and closed based on the condensate level in the compressed air cooler 12, or can be controlled by flow control based on a condensate flowmeter (not shown) arranged in the condensate line piping L2.

[0063] The cooling water pump 14 is disposed in the cooling water line pipe L3 and supplies the cooling water led out from the storage unit 131 of the wet water cooler 13 to the cold end of the compressed air cooler 12 in order to cool the compressed air.

[0064] The dry water cooler 15 cools the cooling water led out from the warm end of the compressed air cooler 12. The motor of the blower is driven to cool the water. The dry water cooler 15 cools the water by indirectly exchanging heat between the cooling water and the air sent from the blower.

[0065] The atmospheric line pipe L1 is a pipe that feeds atmospheric air to the air compressor 11 and feeds compressed air from the air compressor 11 to the compressed air cooler 12 .

[0066] The first condensed water line pipe L2 is a pipe that conveys condensed water from the storage portion 12 a of the compressed air cooler 12 to the wet water cooler 13 .

[0067] The cooling water line pipe L3 delivers cooling water from the storage portion 131 of the wet water cooler 13 to the cold end of the compressed air cooler 12. The cooling water line pipe L3 is a pipe that delivers the cooling water that has been cooled from the warm end of the compressed air cooler 12 to the dry water cooler 15 to the wet water cooler 13.

[0068] According to the first embodiment, compressed air is widely used in industry, and when the compressed air is cooled, water vapor from the atmosphere condenses to obtain condensed water. If the condensed water is supplied to the wet cooler 13, a part of the evaporation loss of the cooling water can be supplied, or the load of the wet water cooler 13 can be increased to suppress the cooling load of the dry water cooler 15, and the power consumption required by the blower used in the dry water cooler 15 can be reduced.

[0069] Since the compressed air cooler 12 can be operated at a higher pressure than the cooling water line pipe L3, the flow rate regulating valve 121 is arranged in the first condensate line pipe L2 to control the energy loss caused by the pressure reduction when the condensate is discharged from the compressed air cooler 12 to be minimized.

[0070] (Another embodiment)

[0071] The wet water cooler 13 and the dry water cooler 15 are arranged in series, but they may also be arranged in parallel. Figure 4Indicates parallel configuration. The cooling water line piping L3 has a branch pipe L31 branched on the way from the warm end of the compressed air cooler 12 to the dry water cooler 15. The branch pipe L31 is a pipe that transports water from the warm end of the compressed air cooler 12 to the wet water cooler 13. In addition, the cooling water cooled by the dry water cooler 15 merges with the cooling water line piping L3 upstream of the cooling water pump 14.

[0072] (Implementation Method 2)

[0073] use Figure 2 , the water cooling system A2 according to the second embodiment is described.

[0074] The water cooling system A2 includes a compressed air cooler 12, a wet water cooler 13, a cooling water pump 14, a dry water cooler 15, a water buffer 16, and a first control unit 18. The same components as those in the first embodiment will be omitted from description.

[0075] The service channels of power, water resources, etc. of the cooling water system A2 are not necessarily stable, and therefore, in order to operate the system stably under any circumstances, it is preferable to have a buffer.

[0076] The water buffer 16 can store the supply water (industrial water, etc.) from outside the system together with the condensed water. Since the condensed water may contain components in the atmosphere as impurities, it can also be purified by a purification device alone or together with the supply water. The purification device can also be arranged between the water buffer 16 and the wet water cooler 13.

[0077] Since condensed water comes from the atmosphere, the amount that can be recovered is not necessarily stable. Therefore, by providing the water buffer 16, stable condensed water management can be performed.

[0078] The water buffer 16 has a storage unit 161. Water can be supplied to the water buffer 16. In addition, the first condensed water line pipe L2 is connected from the storage unit 12a of the compressed air cooler 12 to the storage unit 161, and conveys condensed water.

[0079] The second condensed water line pipe L21 is a pipe that conveys condensed water (make-up water) from the storage portion 161 of the water buffer 16 to the storage portion 131 of the wet water cooler 13 .

[0080] The second flow regulating valve 122 is provided in the second condensate line piping L21. The second flow regulating valve 122 regulates the flow of condensate (make-up water). The second flow regulating valve 122 can be opened and closed by timer control, can be opened and closed based on the condensate liquid level of the storage part 161 of the water buffer 16 and / or the liquid water level of the storage part 131 of the wet water cooler 13, and can also be controlled by flow control based on a condensate flow meter arranged in the second condensate line piping L21.

[0081] The first level gauge 22 measures the amount of cooling water in the reservoir 131 of the wet water cooler 13. The second level gauge 21 measures the amount of water in the reservoir 161 of the water buffer 16.

[0082] The first control unit 18 controls the first flow rate regulating valve 121 and the second flow rate regulating valve 122 based on the data of the first level meter 22 and the second level meter 21 to control the supply amount of condensed water (make-up water).

[0083] The first control unit 18 may also control the driving of the cooling water pump 14 .

[0084] (Implementation 3)

[0085] use Figure 3 , the water cooling system A3 of the third embodiment is described.

[0086] The water cooling system A3 includes a compressed air cooler 12, a wet water cooler 13, a cooling water pump 14, a dry water cooler 15, a water buffer 16, a first control unit 18, and a second control unit 19. The description of the same components as those in the first and second embodiments will be omitted.

[0087] The second control unit 19 controls the operation rate of the dry water cooler 15, specifically, controls the blower, according to the increase or decrease of the power cost. The power cost data is sent from an external device that stores the change of the power cost.

[0088] When the power cost is high, the operation rate of the dry water cooler 15 is adjusted. In addition, the first control unit 18 introduces condensed water from the water buffer 16 into the wet cooling water tower 13 to adjust the operation rate thereof.

[0089] Furthermore, when the power supply capacity of solar power generation, wind power generation, etc. varies depending on the environment, it is necessary to adjust the load of each of the dry water cooler 15 and the wet water cooler 13 .

[0090] For example, control is performed such that the dry water cooler 15 is mainly operated with cheap electricity during the day when solar power generation is possible, and the load of the wet water cooler 13 is increased at night as the unit price of electricity rises.

[0091] At this time, control is performed to store the condensed water obtained from the compressed air cooler 12 in the water buffer 16 during the day, and to supply the water demand of the wet water cooler 13 at night with the water stored in the water buffer 16. That is, the economy of the cooling water system can be improved by using the condensed water under the condition of the highest value in comparison with the electricity price.

[0092] Economic data such as the unit price of electricity is used to determine the operation method of the cooling water system A3, that is, the load sharing of the dry water cooler 15 (mainly consuming electricity) and the wet water cooler 13 (mainly consuming water). When it is determined that the electricity cost is low, the dry water cooler 15 is mainly operated and the condensed water is stored in the water buffer 16. When it is determined that the electricity cost is high, the load of the dry water cooler 15 is reduced and the load of the wet water cooler 13 is increased.

[0093] The load of the wet water cooler 13 can be detected by the loss of water due to evaporation, specifically, the decrease in the water level of the storage section 131 of the wet water cooler 13, so make-up water (condensed water or a mixture of condensed water and water) is supplied from the water buffer 16 in such a way that the water level converges to the management value.

[0094] In determining the load adjustment of the dry water cooler 15, the amount of water (water level) in the water buffer 16 may also be considered. In this way, even when the water level in the water buffer 16 is lowered, the system can be operated in a manner that stabilizes the cooling water temperature by increasing the load of the dry water cooler 15.

[0095] (Example)

[0096] The results of physical simulation of the third embodiment are shown.

[0097] The following situation was studied: the inlet conditions were 35°C, 80% relative humidity, 1 barA of air 100,000 Nm 3 / h is compressed and cooled by an air compressor with 4 compression stages to obtain compressed air with an outlet condition of 42°C, 100% relative humidity and 10 barA.

[0098] Under the inlet conditions, the water contained in the air is 3786 kg / h, and under the outlet conditions, it is saturated and only 684 kg / h exists as water vapor. Therefore, the difference of 3102 kg / h can be recovered as condensed water.

[0099] The latent heat of evaporation of water is 575 cal / g at 40°C. Therefore, when the cooling water temperature is 40°C, 3102 kg / h of condensed water can cool the cooling water by 1783 Mcal / h of latent heat of evaporation.

[0100] The power required for a dry water cooler varies depending on the difference between the atmospheric temperature and the cooling water temperature. Generally, the smaller the temperature difference, the more air flow is required. For example, when delivering 35°C atmospheric air and obtaining 40°C cooling water, 1Mcal / h of cooling consumes 0.052kW of electricity.

[0101] If the condensed water is used for water cooling, it is possible to reduce electric power by 1783 Mcal / h×0.052 kWh / Mcal=93 kW.

[0102] The optimization of water cooling of a heat load of 7400Mcal / h (equivalent to the cooling demand of the above-mentioned air compressor) by dry water cooler and wet water cooler using condensate water was studied under different electricity costs during day and night.

[0103] The daytime is assumed to be 12 hours, and the electricity cost at that time is assumed to be 20 yen / kWH. The nighttime is assumed to be 12 hours, and the electricity cost at that time is assumed to be 60 yen / kWH.

[0104] When the condensed water is continuously used in the wet cooler regardless of day or night, the load of the dry water cooler is reduced by 93 kW, and 292 kW (=7400 Mcal / h×0.052 KWh / Mcal−93 kW) of electric power is used.

[0105] In this case, the electricity cost per day is 20 yen / kWH×292 kW×12 hours+60 yen / kWH×292 kW×12 hours=280,320 yen.

[0106] On the other hand, when only the dry water cooler is operated and condensed water is stored during the day, and both the supplied condensed water and the stored condensed water are used at night, the load of the dry water cooler is 385 kW during the day, while 199 kW (= 385 kW - 186 kW) of electricity is used at night.

[0107] In this case, the electricity cost per day is 20 yen / kWH×385 kW×12 hours+60 yen / kWH×199 kW×12 hours=235,680 yen.

[0108] That is, it means that by intensively utilizing condensed water at night when electricity costs are high, a reduction in electricity costs of about 16% can be expected every day.

[0109] In this embodiment, although the intention is to use the condensed water obtained by the compression cooling of the air to reduce the power of water cooling and the water supply load, by adjusting the utilization timing of the condensed water according to the power supply capacity that can be generated by utilizing renewable energy, and actively utilizing the condensed water to reduce the power consumption of water cooling, especially in situations where power is likely to be insufficient, the power cost (here implicitly includes the installation cost of generators and batteries that can generate stable power) can be reduced.

[0110] (Another embodiment)

[0111] (1) The compressed air generated in Embodiments 1 to 4 may be supplied to an air separation device.

[0112] (2) Embodiments 1 to 4 are not limited to compressed air, but can also be applied to compressed gas such as LNG or boil-off gas.

Claims

1. A water cooling system comprising: A compressed gas cooler cools the compressed gas compressed by the compressor that takes in the gas to be processed; a wet water cooler, which introduces condensed water produced in the compressed gas cooler as makeup water; a cooling water pump for delivering cooling water led out of the wet water cooler to a cold end of the compressed gas cooler in order to cool the compressed gas; a dry water cooler for cooling the cooling water derived from the warm end of the compressed gas cooler; a first condensate line pipe for conveying condensate derived from the compressed gas cooler; as well as The first flow regulating valve is provided on the first condensate line pipe and regulates the flow of the condensate.

2. The water cooling system according to claim 1, The cooling water line piping is provided, and the cooling water line piping transports the cooling water led out from the wet water cooler to the cold end of the compressed gas cooler, transports it from the warm end of the compressed gas cooler to the dry water cooler, and transports the led cooling water to the wet water cooler.

3. The water cooling system according to claim 1, A water buffer for storing the condensed water is provided.

4. The water cooling system according to claim 3, comprising: a second condensate line pipe for conveying condensate from the water buffer to the wet water cooler; and The second flow regulating valve is provided on the second condensate line pipe to regulate the flow of the condensate.

5. The water cooling system according to claim 1, A first control unit is provided, and the first control unit controls the first flow rate regulating valve to control the supply amount of condensed water.

6. The water cooling system according to claim 4, A first control unit is provided, and the first control unit controls the second flow rate regulating valve to control the supply amount of condensed water.

7. The water cooling system according to claim 1, A second control unit is provided for controlling the operation rate of the dry water cooler according to an increase or decrease in electricity cost.

8. An air separation device comprising the water cooling system according to claim 1.

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