A cooling tower equipped with a device for supplying cooling liquid to reduce the temperature of exhaust gas, and a method for supplying cooling liquid to the cooling tower.

Abstract

To provide a cooling tower that simplifies equipment, reduces installation costs, and improves exhaust gas desalination efficiency. [Solution] The cooling tower is equipped with a cooling liquid supply device 10 that supplies water W or a chemical aqueous solution D as the cooling liquid. The cooling liquid supply device 10 has a dilution tank 1 that dilutes the chemical to a chemical aqueous solution D of the required dilution concentration, and a storage tank 2 to which the cooling liquid is sent from the dilution tank 1 and stored. The cooling liquid supply device 10 has a first supply channel 5 that can send water W from the dilution tank 1 to the storage tank 2, a second supply channel 6 that can send chemical aqueous solution D from the dilution tank 1 to the storage tank 2, and a supply channel 7 that supplies the cooling liquid to the injection section 22. The storage tank 2 has a larger capacity than the dilution tank 1. The first supply channel 5 sends water W at or above a predetermined liquid level M in the dilution tank 1. In the water supply state, water W is supplied via the dilution tank 1, the first liquid delivery channel 5, the storage tank 2, and the supply channel 7. In the chemical aqueous solution supply state, the chemical aqueous solution D is supplied via the dilution tank 1, the second liquid delivery channel 6, the storage tank 2, and the supply channel 7.

Description

Technical Field

[0001] The present invention relates to a desuperheating tower equipped with a supply device for a desuperheating liquid for cooling exhaust gas and a method for supplying the desuperheating liquid to the desuperheating tower.

Background Art

[0002] Conventionally, in exhaust gas treatment equipment, a desuperheating tower is provided for the purpose of cooling exhaust gas and neutralizing (desalting) acidic harmful gases such as hydrogen chloride and sulfur oxides (hereinafter collectively referred to as "HCl·SOx") in the exhaust gas. In the desuperheating tower, as a normal operation, water is sprayed onto the exhaust gas passing through the tower, and the temperature of the exhaust gas is lowered (desuperheated) by contact with water and the heat of vaporization of water. And when HCl·SOx in the exhaust gas increases, in addition to water, a chemical agent (caustic soda solution) is sprayed into the tower as a desalting operation. Thereby, in the tower, the chemical agent contacts the exhaust gas, and HCl·SOx in the exhaust gas is neutralized. There is, for example, a desuperheating tower as described in Patent Document 1 as such a desuperheating tower.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the desuperheating tower as described in Patent Document 1, generally, a water injection part for injecting water into the tower and a chemical agent injection part for injecting a chemical agent are provided separately and configured as separate systems. The water injection part is constantly used during normal operation, while the chemical agent injection part is temporarily used during desalting operation, so it is made into a separate system for its maintenance and the like. Therefore, there are problems such as the need for a supply device including a pump for each system, the equipment becoming complicated, and the installation cost being high.

[0005] Furthermore, because the chemical and water were sprayed separately, the degree of contact between the chemical and the exhaust gas varied unevenly depending on the part of the tower, making it difficult to carry out the neutralization reaction uniformly within the tower. Therefore, it was necessary to set the dilution concentration of the chemical solution to a higher level, or to supply more chemical than the reaction equivalent, which presented challenges in terms of the desalination efficiency of the exhaust gas relative to the amount of chemical supplied.

[0006] Furthermore, in the chemical spraying section, the risk of nozzle blockage due to salt precipitation in the spray nozzle increases as the chemical spraying time per desalination operation lengthens. Therefore, after use (during normal operation), the chemical spraying section is manually removed from the desalination tower for maintenance and cleaning, and then reinstalled in the desalination tower for desalination operations, which presented challenges in terms of work efficiency related to desalination.

[0007] This invention has been made in view of the above problems, and aims to provide a cooling tower that can simplify the equipment, reduce installation costs, and improve the efficiency of exhaust gas desalination. [Means for solving the problem]

[0008] According to the present invention, a cooling tower is provided to reduce the temperature of exhaust gas produced when a workpiece is heat-treated, The cooling tower is A body section formed in which an internal space is created through which exhaust gases pass from bottom to top, An injection unit that sprays a cooling liquid supplied from the outside of the body into the internal space, A cooling liquid supply device that supplies cooling liquid to the injection unit and Equipped with, The cooling solution is water, or an aqueous solution of the drug diluted with water. The detemperature-reducing liquid supply device is A dilution tank for diluting the drug into an aqueous solution of the required dilution concentration, A water supply unit capable of supplying water to the dilution tank, A chemical supply unit capable of supplying chemicals to a dilution tank, A storage tank into which the detemperatureized liquid is supplied from the dilution tank and stored, A first liquid supply channel capable of supplying water above a predetermined liquid level in the dilution tank to the storage tank, A second liquid supply channel that allows the drug aqueous solution to be supplied from the bottom of the dilution tank to the storage tank, A supply path that supplies a cooling liquid from the storage tank to the injection unit. It has, The storage tank has a larger capacity than the dilution tank. In the water supply state, where water is supplied as a temperature-reducing liquid, water is supplied to the injection unit via a dilution tank, a first liquid supply channel, a storage tank, and a supply channel. In the state where a chemical aqueous solution is supplied as a temperature-reducing liquid, the chemical aqueous solution is supplied to the injection unit via a dilution tank, a second liquid supply channel, a storage tank, and a supply channel.

[0009] According to this, when the cooling liquid supply device of the cooling tower is set to water supply mode, it supplies water to the injection unit as the cooling liquid. The injection unit then sprays water into the tower, putting the cooling tower into normal operation mode. Alternatively, when the cooling liquid supply device is set to chemical solution supply mode, it supplies chemical solution to the injection unit as the cooling liquid. The injection unit then sprays the chemical solution into the tower, putting the cooling tower into desalination operation mode.

[0010] In the water supply state, the first liquid supply channel delivers water above a predetermined level in the dilution tank, so that a predetermined level of water is always stored in the dilution tank in the water supply state. Therefore, when switching to the chemical aqueous solution supply state, the water supply time required to dilute the chemical in the dilution tank is shortened. In addition, since the storage tank has a larger capacity than the dilution tank, it is possible to configure it so that the dilution of the chemical in the dilution tank is completed while the cooling liquid remains in the storage tank. As a result, when switching between the water supply state and the chemical aqueous solution supply state, it is possible to supply the cooling liquid to the spray unit without interruption.

[0011] In other words, since water and chemical aqueous solutions can be supplied to the same injection unit using the same supply device, the supply device can be configured with a single system instead of the conventional two systems. This simplifies the equipment and reduces installation costs. Furthermore, since the injection unit is configured as a single system, after spraying the chemical aqueous solution in the desalination operation, it returns to normal operation and sprays water, which naturally cleans the injection nozzle, thus improving the efficiency of maintenance work. In addition, when the chemical aqueous solution is supplied, the chemical aqueous solution, which has been prepared in advance to the required dilution concentration, is supplied to the injection unit and sprayed into the cooling tower, so that the neutralization reaction proceeds uniformly within the cooling tower and acidic harmful gases are efficiently neutralized.

[0012] The de-cooling liquid supply device for the de-cooling tower according to this second invention is: An acid hazardous gas concentration acquisition unit that acquires the concentration of acid hazardous gases in exhaust gas as the measured acid hazardous gas concentration, A control unit capable of switching between a water supply state and a chemical solution supply state. It has, The control unit switches between supplying water and supplying a chemical solution based on a comparison between the measured acid gas concentration and a predetermined set value.

[0013] According to this, the control unit of the cooling liquid supply device of the cooling tower can be configured to switch from a water supply state to a chemical aqueous solution supply state when the measured acidic gas concentration exceeds a set value, and to switch back from a chemical aqueous solution supply state to a water supply state when the measured acidic gas concentration falls below the set value. This ensures that the concentration of acidic harmful gases in the exhaust gas is kept below a predetermined set value.

[0014] The de-cooling liquid supply device for the de-cooling tower according to the third invention is: It has a dilution level acquisition unit that acquires the liquid level in the dilution tank as the measured dilution level, The control unit adjusts the supply amounts of drug and water from the drug supply unit and the water supply unit so that a predetermined amount of drug and a predetermined amount of water corresponding to the required dilution concentration are supplied, based on the measured dilution level value.

[0015] According to this, in the coolant supply device of the cooling tower, the water supply section and the chemical agent supply section are controlled so that a predetermined amount of water and a predetermined amount of chemical agent corresponding to a preset required dilution concentration are supplied, and the chemical agent is accurately diluted to the required dilution concentration. Therefore, in the state of supplying the chemical agent aqueous solution, the acidic harmful gas is efficiently neutralized by supplying the coolant with the required dilution concentration.

[0016] The exhaust gas treatment facility according to the fourth invention includes any one of the cooling towers from the first invention to the third invention. It is further provided with a dust collector that is communicated with the cooling tower through a communication passage and dusts the exhaust gas discharged from the cooling tower. A neutralizing agent for neutralizing acidic harmful gas is supplied in the communication passage or the dust collector.

[0017] According to this, in the exhaust gas treatment facility, for example, slaked lime or the like is injected as a neutralizing agent into the exhaust gas discharged from the cooling tower, so that the acidic harmful gas in the exhaust gas can be superposed and neutralized together with the cooling tower.

[0018] The waste incineration facility according to the fifth invention includes the exhaust gas treatment facility of the fourth invention. It is further provided with an incinerator for incinerating the object to be treated. The cooling tower is for lowering the temperature of the exhaust gas discharged from the incinerator.

[0019] According to this, the waste treatment facility can efficiently neutralize the acidic harmful gas contained in the exhaust gas discharged by incinerating the object to be treated such as industrial waste with large compositional fluctuations.

[0020] The coolant supply method of the cooling tower according to the sixth invention is a coolant supply method in a cooling tower that lowers the temperature of the exhaust gas generated by heat-treating the object to be treated with the coolant. The cooling tower has a body portion in which an internal space is formed through which the exhaust gas passes from below to above, an injection portion that injects the coolant supplied from the outside of the body portion into the internal space, a dilution tank in which the chemical agent is diluted, A water supply unit capable of supplying water to the dilution tank, A chemical supply unit capable of supplying chemicals to a dilution tank, A storage tank for storing the reduced-temperature liquid from the dilution tank and Equipped with, The cooling solution is water, or an aqueous solution of the drug diluted with water. The storage tank has a larger capacity than the dilution tank. The water supply conditions for supplying water to the cooling tower include: Water is supplied to the dilution tank. Water above a predetermined liquid level in the dilution tank is sent to the storage tank. The pumped water is supplied from the storage tank to the injection unit. The chemical solution supply condition for supplying the chemical solution to the de-temperature tower is: The chemical and water are supplied to the dilution tank. The drug is diluted in a dilution tank to an aqueous solution of the required dilution concentration. The aqueous solution of the drug is sent from the bottom of the dilution tank to the storage tank. The liquid-transported drug solution is supplied from the storage tank to the injection unit.

[0021] According to this, the method for supplying the cooling liquid to the cooling tower can achieve the same effects as the first invention.

[0022] The method for supplying cooling liquid to a cooling tower according to the seventh invention is: The concentration of acidic harmful gases in the exhaust gas is obtained as the measured acidic gas concentration. Based on a comparison between the measured acidic gas concentration and a predetermined set value, the system switches between supplying water and supplying a chemical solution.

[0023] According to this, the method for supplying the cooling liquid to the cooling tower can achieve the same effects as the present second invention.

[0024] The method for supplying cooling liquid to a cooling tower according to the eighth invention is such that, while the supply of cooling liquid to the cooling tower continues, the amount of cooling liquid stored in the storage tank is adjusted so that some cooling liquid remains in the storage tank when the dilution of the chemical agent is completed in the dilution tank.

[0025] According to this, the method of supplying the cooling liquid to the cooling tower ensures that the dilution of the chemical in the dilution tank is completed while the cooling liquid remains in the storage tank. Therefore, when switching between the water supply state and the chemical aqueous solution supply state, it is possible to supply the cooling liquid to the injection unit without interruption or stopping. [Effects of the Invention]

[0026] According to the present invention, the injection unit for the desalination liquid and its supply device can be configured as one system instead of the conventional two systems, thereby simplifying the equipment, reducing installation costs, and improving desalination efficiency. [Brief explanation of the drawing]

[0027] [Figure 1] This figure shows a waste treatment facility in which a cooling tower according to an embodiment of the present invention is used. [Figure 2] This is a cross-sectional view of the same de-cooling tower. [Figure 3] This is a cross-sectional view along line AA in Figure 2. [Figure 4] This is a schematic diagram of the supply system for the cooling liquid to the cooling tower. [Figure 5] This figure shows the relationship between the dilution concentration of the drug solution, the required amount of drug, and the amount of water used for dilution. [Figure 6] This is a flowchart illustrating the operation switching process in the same defrosting tower. [Figure 7] This is a flow chart showing the water supply process in the supply device. [Figure 8] This is a schematic diagram showing the water supply status in the supply device. [Figure 9] This is a flow chart showing the preparation process of the drug aqueous solution in the supply device. [Figure 10] This is a schematic diagram showing the preparation state of the drug solution in the supply device. [Figure 11] This is the same schematic diagram, showing the following state as in Figure 10. [Figure 12] This is a flowchart illustrating the drug solution supply process in the supply device. [Figure 13] This is a schematic diagram showing the supply status of the drug solution in the supply device. [Figure 14] This diagram shows the relationship between the dilution concentration of the drug solution and the preparation time of the drug solution, specifically for the initial supply of the drug solution. [Figure 15] This diagram illustrates the same relationship, specifically showing the case when supplying the drug solution for the second time and beyond. [Figure 16] This is a cross-sectional view showing the configuration of a conventional cooling tower. [Modes for carrying out the invention]

[0028] [Waste treatment facility 100] Referring to Figure 1, a waste treatment facility 100 in which a cooling tower 20 according to an embodiment of the present invention is used will be described.

[0029] As shown in Figure 1, the waste treatment facility 100 includes an incinerator 31, a cooling tower 20 for reducing the temperature of the exhaust gas G from the incinerator 31, a dust collector 32 for removing dust from the cooled exhaust gas G, an induced draft fan B for drawing in the exhaust gas G from the dust collector 32, and a chimney 33. The incinerator 31 burns the waste (an example of industrial waste, the material to be treated) received from a hopper 31b, etc., and discharges high-temperature exhaust gas G generated by the combustion. The high-temperature exhaust gas G contains soot, SO2, and other particles. X HCl, NO X DXN S It contains harmful substances such as [specific types of harmful substances].

[0030] The cooling tower 20 cools the exhaust gas G that flows in from the incinerator 31 at a high temperature by spraying (an example of injection) a cooling liquid (water W, or an aqueous solution of chemical C: hereinafter referred to as chemical aqueous solution D) onto the exhaust gas G. As described above, the cooling tower 20 normally sprays water W during operation, and switches to desalination operation depending on the amount of acidic harmful gas (e.g., HCl concentration [ppm]) contained in the exhaust gas G, and sprays chemical aqueous solution D onto the exhaust gas G. Chemical C is, for example, caustic soda (NaOH), which reacts with HCl·SOx (an example of acidic harmful gas) in the exhaust gas G to precipitate salts [sodium chloride (NaCl), sodium sulfite (Na2SO3), etc.]. This reduces the HCl·SOx concentration in the exhaust gas G.

[0031] The cooling liquid (water W or chemical aqueous solution D) is supplied from the cooling liquid supply device 10 through the supply passage 7 (details will be described later). Water W and chemical C are supplied to the cooling liquid supply device 10 from the water storage tank 34 and the chemical storage tank 35, respectively.

[0032] A neutralizing agent supply device 36 is provided in the flue 20c (an example of a connecting passage) downstream of the cooling tower 20 and upstream of the dust collector 32. The neutralizing agent supply device 36 supplies powdered slaked lime [Ca(OH)2] (an example of a neutralizing agent) to the exhaust gas G from the cooling tower 20. This neutralizes the HCl·SOx in the exhaust gas G that has passed through the cooling tower 20. As a result, the HCl·SOx concentration is reliably reduced to below a predetermined set value.

[0033] The exhaust gas G, after HCl·SOx has been neutralized, is then treated with NO by a catalytic tower (not shown in the diagram). X After other harmful substances such as are removed, the exhaust gas G is discharged outside the facility via the chimney 33 by the induced draft fan B. Near the outlet of the chimney 33, an HCl·SOx concentration acquisition unit 11 is provided to obtain the concentration of HCl·SOx in the exhaust gas G as a measured concentration (e.g., [ppm]).

[0034] The exhaust gas treatment equipment 30 consists of a cooling tower 20, a cooling liquid supply device 10, a dust collector 32, and a neutralizing agent supply device 36. In the exhaust gas treatment equipment 30, the exhaust gas G discharged from the cooling tower 20 is always desalinated by the neutralizing agent supply device 36. In other words, when the cooling tower 20 is in normal operation, the exhaust gas G is desalinated by the neutralizing agent supplied from the neutralizing agent supply device 36. When the cooling tower 20 is in desalting operation, the exhaust gas G is desalinated in a superimposed manner by the cooling tower 20 and the neutralizing agent supply device 36, efficiently reducing the HCl·SOx concentration.

[0035] The present invention aims to simplify the equipment necessary for supplying cooling liquid during each operation, reduce installation costs, and improve the desalination efficiency of exhaust gas G in the cooling tower 20 of the waste treatment facility 100 and exhaust gas treatment equipment 30 described above.

[0036] [Configuration of the cooling tower 20] Referring to Figures 2 and 3, the configuration of the cooling tower 20 according to the present invention will be described. As shown in Figure 2, the cooling tower 20 comprises a body 21 having an internal space S through which exhaust gas G passes from a lower gas supply port 23 to an upper gas outlet 24, and a spray unit 22 (an example of an injection unit) that sprays cooling liquid into the internal space S from outside the body 21.

[0037] Inside the body section 21, a guide cylinder 25 is provided to guide the exhaust gas G from the gas supply port 23 upward. The upper end of the guide cylinder 25 has an enlarged diameter section 25b that widens upward. The exhaust gas G entering from the gas supply port 23 swirls within the internal space S and is guided by the guide cylinder 25, flowing into the internal space S as an upward flow.

[0038] The spray unit 22 has a cylindrical body that penetrates the body 21 and guide tube 25 from the outside, and a spray nozzle 22b provided at the tip of the body protrudes into the inside of the body 21. The spray nozzle 22b opens diagonally upward, and the cooling liquid supplied from the outside through the body is sprayed diagonally upward from the spray nozzle 22b into the internal space S. The exhaust gas G flowing through the internal space S as an upward flow is cooled by gas-liquid contact with the cooling liquid sprayed during its flow. Furthermore, when an aqueous chemical solution D is supplied as the cooling liquid, the exhaust gas G and the aqueous chemical solution D come into gas-liquid contact in the internal space S, causing both cooling and desalination.

[0039] As shown in Figure 3 (a cross-sectional view along line AA in Figure 2), three spray units 22 are provided in this embodiment. Each spray unit 22 is positioned at three equally spaced locations in a cross-sectional view of the body 21. Cooling liquid is supplied to each spray unit 22 from the cooling liquid supply device 10 through the supply passage 7.

[0040] [Configuration of the temperature-reducing liquid supply device 10] Referring to Figure 4, the configuration of the desiccant liquid supply device 10 will be described. The desiccant liquid supply device 10 comprises a dilution tank 1 capable of diluting the chemical agent C (in this embodiment, for example, a 24% aqueous solution of caustic soda) and a storage tank 2 to which water W or the aqueous chemical agent solution D is supplied from the dilution tank 1 and stored as a desiccant liquid. In the dilution tank 1, a predetermined amount of water W and a predetermined amount of chemical agent C are supplied, and the chemical agent C is diluted to the required dilution concentration. The dilution tank 1 and the storage tank 2 are provided with a dilution liquid level acquisition unit 13 and a storage liquid level acquisition unit 14, respectively.

[0041] Dilution tank 1 and storage tank 2 are each provided with liquid level indicators that show the amount of liquid in the tank. In this embodiment, for example, the liquid level and the amount of liquid in dilution tank 1 are: liquid level H (maximum capacity): 600L, liquid level M: 300L, and liquid level LL (lower limit capacity). Similarly, the liquid level and the amount of liquid in storage tank 2 are: liquid level H (maximum capacity): 1400L, liquid level M: 800L, liquid level L: 500L, and liquid level LL (lower limit capacity). In other words, in this embodiment, the maximum capacity of storage tank 2 is configured to be greater than the maximum capacity of dilution tank 1. Furthermore, the capacity of storage tank 2 above liquid level M (i.e., liquid level H: 1400L - liquid level M: 800L = 600L) is configured to be equal to the maximum capacity of dilution tank 1 (600L).

[0042] The temperature-reducing liquid supply device 10 includes a water supply unit 3, a chemical supply unit 4, a first liquid supply channel 5, a second liquid supply channel 6, and a control unit 12. The control unit 12 is connected to a dilution liquid level acquisition unit 13, a storage liquid level acquisition unit 14, and an HCl·SOx concentration acquisition unit 11.

[0043] The dilution level acquisition unit 13 acquires the liquid level (e.g., [mm]) of water W or chemical aqueous solution D in the dilution tank 1 as the measured dilution level 1h. The storage level acquisition unit 14 measures the liquid level (e.g., [mm]) of water W or chemical aqueous solution D stored in the storage tank 2 as the measured storage level 2h. The dilution level acquisition unit 13 and the storage level acquisition unit 14 are liquid level measuring instruments such as microwave level meters.

[0044] The water supply unit 3 supplies water W from the water storage tank 34 (see Figure 1) to the dilution tank 1 via the water supply channel 3c. The chemical supply unit 4 supplies chemical C from the chemical storage tank 35 (see Figure 1) to the dilution tank 1 via the chemical supply channel 4c. A predetermined amount of chemical C (required amount of chemical) and a predetermined amount of water W (amount of dilution water) are supplied to the dilution tank 1, and the chemical C is diluted to the required dilution concentration. In this embodiment, the required amount of chemical and the amount of dilution water are set, for example, from the relationship between the dilution concentration and the required amount of chemical and dilution water shown in Figure 5. In this embodiment, the required dilution concentration is set, for example, within the range shown in Figure 5.

[0045] The first liquid supply channel 5 supplies water W from the dilution tank 1 to the storage tank 2. The first liquid supply channel 5 is provided with an inverted U-shaped pipe section 5b. The inverted U-shaped pipe section 5b is located at a predetermined liquid level (e.g., liquid level M) in the dilution tank 1. The inverted U-shaped pipe section 5b functions as a valve; when the liquid level in the dilution tank 1 exceeds liquid level M, it becomes possible to supply water from the dilution tank 1 to the storage tank 2. If the liquid level is below liquid level M, an air layer forms at the top of the inverted U-shaped pipe section 5b, preventing the supply of water from the dilution tank 1 to the storage tank 2. In other words, the first liquid supply channel 5 supplies water W at or above a predetermined liquid level (liquid level M) in the dilution tank 1 to the storage tank 2. The inverted U-shaped pipe section 5b may also be configured as a simple outlet located at a predetermined liquid level.

[0046] The second liquid supply channel 6 is a pipe for supplying the chemical aqueous solution D from the dilution tank 1 to the storage tank 2. The second liquid supply channel 6 has an inlet 6b on the bottom of the dilution tank 1, for example. In other words, the second liquid supply channel 6 can supply the chemical aqueous solution D to the storage tank 2 up to the liquid level LL (lower limit) in the dilution tank 1.

[0047] The water supply channel 3c, chemical supply channel 4c, first liquid delivery channel 5, and second liquid delivery channel 6 are each equipped with a water supply valve Vw, a chemical supply valve Vc, a first valve V1, and a second valve V2, respectively, and are configured to be openable and closable. The water supply valve Vw, chemical supply valve Vc, first valve V1, and second valve V2 are each connected to a control unit 12, and their opening and closing are controlled by the control unit 12.

[0048] As will be described in detail later, the control unit 12 controls the opening and closing of each valve based on the measured dilution level 1h and the measured storage level 2h. The control unit 12 switches between the water supply state and the chemical aqueous solution supply state in the temperature-reducing liquid supply device 10 based on the measured concentration from the HCl·SOx concentration detection unit. In the following figures, the control unit 12, HCl·SOx concentration acquisition unit 11, dilution level acquisition unit 13, and storage level acquisition unit 14 are omitted from the illustration.

[0049] [Operation switching process in the cooling tower 20] Referring to Figure 6, the operation switching process in the cooling tower 20 will be explained. As shown in the figure, in normal operation (step S11), the cooling liquid supply device 10 of the cooling tower 20 is in a water supply state (step S12: details will be described later), and water W is supplied as the cooling liquid to the spray unit 22 and sprayed from the spray unit 22 into the cooling tower 20 (step S13).

[0050] The control unit 12 checks at predetermined intervals whether the HCl·SOx measurement concentration is equal to or greater than a predetermined set value (example of comparison result) (step S14). If the HCl·SOx measurement concentration is less than the set value (No in step S14), normal operation continues (step S11). If the HCl·SOx measurement concentration is equal to or greater than the set value (Yes in step S14), the system switches to desalination operation (step S15).

[0051] At this time, the control unit 12 determines the dilution concentration of the drug aqueous solution D based on the difference between the measured HCl·SOx concentration and the set value (step S16). The dilution concentration may be determined based on a pre-prepared correspondence table between the difference and the dilution concentration, or it may be configured to be automatically determined using control parameters that have been identified in advance by PID control or the like.

[0052] The desiccant liquid supply device 10 enters a state of preparing the chemical solution by diluting the chemical C to obtain a chemical solution D of the determined dilution concentration, and then enters a state of supplying the chemical solution (step S17: details will be described later). The chemical solution D is then supplied to the spray unit 22 as the desiccant liquid and sprayed from the spray unit 22 into the desiccant tower 20 (step S18).

[0053] After a predetermined time has elapsed, the HCl·SOx measurement concentration is acquired again, and it is checked whether the HCl·SOx measurement concentration is below the set value (step S14). If the HCl·SOx measurement concentration is below the set value (No in step S14), the system returns to normal operation (step S11). If the HCl·SOx measurement concentration is above the set value (Yes in step S14), the desalination operation continues (step S15).

[0054] [Water supply treatment] The process of the water supply state (step S12 in Figure 6) in the desaturated liquid supply device 10 will be explained with reference to Figures 7 and 8. As shown in step S21 in Figure 7, the first valve V1 of the first liquid supply passage 5 is opened during the water supply process (see Figure 8).

[0055] As described above, the first liquid supply channel 5 is provided with an inverted U-shaped pipe section 5b, so that when the liquid level in the dilution tank 1 is below liquid level M, the liquid supply by the first liquid supply channel 5 stops. The control unit 12 acquires the measured stored liquid level 2h at predetermined intervals and checks the liquid level (step S22 in Figure 7). If the measured stored liquid level 2h is above liquid level L (No in step S22), it remains on standby and repeats the check process at predetermined intervals. When the measured stored liquid level 2h falls below liquid level L (Yes in step S22) (see dashed line in Figure 8), the water supply valve Vw is opened (step S23) and water supply from the water supply unit 3 begins.

[0056] The control unit 12 acquires the measured storage liquid level 2h at predetermined intervals and confirms the liquid level (step S24). When the measured storage liquid level 2h is less than liquid level M (No in step S24), the water supply valve Vw remains open (step S23). When the measured storage liquid level 2h reaches liquid level M (Yes in step S24) (see solid line in Figure 8), the water supply valve Vw is closed (step S25), the water supply from the water supply unit 3 is stopped, and the process is terminated (END). In other words, in the water supply state, the detemperatureized liquid (water W) in the storage tank 2 is kept below liquid level M. This ensures that there is sufficient free space in the storage tank 2, so that it is able to receive the chemical aqueous solution D from the dilution tank 1. The first liquid supply channel 5 is provided with an inverted U-shaped pipe section 5b, so that water W at liquid level M is always secured in the dilution tank 1 in the water supply state.

[0057] [Preparation of chemical solution] The process of preparing the chemical aqueous solution in the temperature-reducing liquid supply device 10 (step S17 in Figure 6) will be explained with reference to Figures 9 to 11.

[0058] As shown in step S31 of Figure 9, in the preparation of the aqueous drug solution, all valves are first closed. Then, the dilution concentration determined in step S16 of Figure 6 is set as the required dilution concentration (step S32).

[0059] For the purposes of this explanation, let's assume that the required dilution concentration is determined to be, for example, 5 [wt.%]. As shown in Figure 5, the corresponding required amount of chemical agent is 125 L, and the amount of dilution water is 475 L. The control unit 12 calculates and stores the target chemical level and target water level, respectively, by dividing these by the cross-sectional area of ​​the dilution tank 1, for example.

[0060] The control unit 12 first opens the water supply valve Vw (step S33 in Figure 9), and then acquires the measured dilution level 1h at predetermined intervals and confirms the level (step S34). If the measured dilution level 1h has not reached the target level (No in step S34), the control unit 12 keeps the water supply valve Vw open (step S33) (see Figure 10). When the measured dilution level 1h reaches the target level (Yes in step S34), the control unit 12 closes the water supply valve Vw (step S35).

[0061] In this case, because the first liquid supply channel 5 is equipped with an inverted U-shaped pipe section 5b, a constant amount of water W is always maintained in the dilution tank 1 at liquid level M (300L). Therefore, the amount of additional water that needs to be supplied is only 175L (=475L-300L). In other words, the water supply time is shortened.

[0062] Subsequently, the control unit 12 opens the drug supply valve Vc and starts stirring with the agitator 1s (step S36) (see Figure 11). The control unit 12 then acquires the measured dilution level 1h at predetermined intervals and confirms the liquid level (step S37). If the measured dilution level 1h has not reached the target drug level (i.e., liquid level H) (No in step S37), the drug supply valve Vc is kept open. When the measured dilution level 1h reaches the target drug level (Yes in step S37), the drug supply valve Vc is closed (step S38).

[0063] In this embodiment, in order for drug C to be homogeneously mixed in the drug aqueous solution D, the minimum stirring time is set to, for example, 300 seconds (stirring condition a), and an additional 60 seconds of stirring is required after the supply of drug C is complete (stirring condition b). For example, when the drug supply time is 240 seconds or less, stirring time of 300 seconds will satisfy stirring conditions a and b. When the drug supply time exceeds 240 seconds, stirring will be performed additionally after the supply of drug C is complete to satisfy stirring conditions a and b.

[0064] The above is shown in steps S39 to S42. In other words, the control unit 12 first checks whether the drug supply time (i.e., stirring time) was within 240 seconds (step S39). If it is within 240 seconds (Yes in step S39), the stirring time is checked (step S40). If the stirring time is less than 300 seconds (No in step S40), stirring continues. When the stirring time reaches 300 seconds (Yes in step S40), stirring is stopped (step S42), and the preparation of the drug aqueous solution D is completed (END).

[0065] If the drug supply time exceeds 240 seconds (No in step S39), the stirring time is checked (step S41). If the stirring time is less than [drug supply time + 60 seconds] (No in step S41), stirring continues. When the stirring time reaches [drug supply time + 60 seconds] (Yes in step S41), stirring is stopped (step S42), and the preparation of drug aqueous solution D is completed (END). [Chemical solution supply treatment]

[0066] Referring to Figures 12 and 13, the process of supplying the chemical aqueous solution in the temperature-reducing liquid supply device 10 (step S17 in Figure 6) will be explained. As shown in step S51 in Figure 12, in the chemical aqueous solution preparation process, all valves are first closed (step S51).

[0067] The control unit 12 acquires the measured storage liquid level 2h at predetermined intervals and confirms the liquid level (step S52). If the measured storage liquid level 2h is below liquid level M (No in step S52), it remains in standby mode and repeats the confirmation process at predetermined intervals. When the measured storage liquid level 2h becomes below liquid level M (Yes in step S52) (see dashed line in Figure 13), the second valve V2 is opened (step S53), and the drug aqueous solution D is sent from the dilution tank 1 to the storage tank 2. As a result, the drug aqueous solution D is sent from the dilution tank 1 to the storage tank 2 with a capacity of at least liquid level M available (i.e., the maximum capacity of the dilution tank 1: 600L). Therefore, the entire amount of the drug aqueous solution D from the dilution tank 1 can be received by the storage tank 2.

[0068] The control unit 12 acquires the measured dilution level 1h in the dilution tank 1 at predetermined intervals and confirms the liquid level (step S54). If the measured dilution level 1h has not reached the liquid level LL (lower limit) (No in step S54), it remains on standby and repeats the confirmation process at predetermined intervals. When the measured dilution level 1h reaches the liquid level LL (lower limit) (Yes in step S54) (see solid line in Figure 13), the second valve V2 is closed (step S55) and the process ends (END). As a result, all of the prepared chemical aqueous solution D is sent to the storage tank 2. In parallel with the supply of the chemical aqueous solution D from the dilution tank 1 to the storage tank 2, the chemical aqueous solution D is supplied from the storage tank 2 to the spray unit 22.

[0069] When one processing cycle, from the start of water supply to dilution tank 1 as described above until the completion of liquid transfer to storage tank 2 (i.e., until the dilution of chemical C is complete), is considered one batch, the above description concerns the processing of the first batch (immediately after switching from water supply state to chemical solution supply state). Although not shown in the diagram, for the second batch and beyond, water is supplied from a state where dilution tank 1 is empty.

[0070] The relationship between the time required per batch and the dilution concentration is shown in Figures 14 and 15. Figure 14 shows the time required for the first batch, and Figure 15 shows the time required for the second batch and subsequent batches.

[0071] As described above, the provision of an inverted U-shaped pipe section 5b in the first liquid supply channel 5 shortens the water supply time for the first batch. Therefore, the time required for the first batch shown in Figure 14 is shorter than the time required for the second batch and subsequent batches shown in Figure 15. As described above, in the water supply state, the desiccant liquid in the storage tank 2 is supplied at a liquid level below level M (i.e., with a small storage volume while ensuring sufficient free space). However, because the time required for the first batch is short, it is possible to ensure that the supply of desiccant liquid to the spray section 22 is carried out without interruption or stopping.

[0072] As shown in Figure 15, although there are slight variations due to differences in the supply time of water W and chemical C, and the stirring time of the tank, the preparation time is generally 10 minutes (600 sec) or less even for the second batch and beyond. In other words, since the maximum capacity of dilution tank 1 is 600 L, it is possible to prepare more than 60 L per minute. Therefore, for example, by configuring the supply amount from storage tank 2 to spray unit 22 to be 60 L or less per minute, storage tank 2 can prepare more chemical aqueous solution D in dilution tank 1 than the amount supplied to spray unit 22. In addition, since the maximum capacity of storage tank 2 (1400 L) is configured to be larger than the maximum capacity of dilution tank 1 (600 L), a sufficient amount of desaturated liquid can be stored in storage tank 2.

[0073] As a result, when the preparation of the chemical solution D is complete in the dilution tank 1, the cooling liquid remains in the storage tank 2. Therefore, when switching between the water supply state and the chemical solution supply state, it is possible to supply the cooling liquid to the spray unit 22 without interruption or stopping.

[0074] Generally, once the HCl·SOx measurement concentration exceeds the set value, the spraying of the chemical solution D into the exhaust gas G is often carried out at intervals of several hours. Therefore, the dilution of chemical C in dilution tank 1 and its delivery are repeated in dozens of batches. When the number of batches is small, the dilution concentration of the chemical solution D in storage tank 2 is lower than the required dilution concentration due to the influence of the water W initially stored in storage tank 2. However, as the number of batches increases, the dilution concentration of the chemical solution D in storage tank 2 approaches the required dilution concentration.

[0075] In this case, since the dilution concentration of the drug aqueous solution D in the storage tank 2 will be lower when the batch size is small, the control unit 12 may be configured to set the dilution concentration higher than the required dilution concentration when the batch size is small. In this case, the control unit 12 may be configured to store a relationship between the batch size prepared in advance and, for example, a coefficient multiplied by the required dilution concentration, and to set the dilution concentration by referring to this relationship.

[0076] As described above, the cooling liquid supply device 10 supplies the cooling liquid, whether it is water W or a chemical aqueous solution D, to the same spray unit 22 through the same supply path 7 without interruption. In other words, the supply path 7 and spray unit 22 only need to be one system instead of the two systems required in conventional devices. Therefore, the equipment can be simplified and installation costs can be reduced.

[0077] Furthermore, when supplying the chemical aqueous solution D, the chemical aqueous solution D, which has been precisely prepared to the required dilution concentration in advance, is sprayed into the defroster 20. As a result, unlike in conventional configurations, a higher dilution concentration is not set due to the uneven dilution concentration of the chemical aqueous solution D in the defroster 20, and the neutralization reaction proceeds uniformly within the defroster 20. Therefore, HCl·SOx is efficiently neutralized.

[0078] Furthermore, the spray unit 22, which is configured as a single system, sprays the chemical aqueous solution D in a desalination operation, and then returns to normal operation to spray water W, thereby naturally cleaning the spray nozzle 22b and keeping it clean. Therefore, unlike conventional configurations, there is no need to remove and reinstall a spray unit dedicated to the chemical for maintenance, thus improving work efficiency.

[0079] Furthermore, as shown in Figure 3, multiple spray units 22 may be installed. Here, as shown in Figure 16, in the conventional defrosting tower 90, the rated flow rate, actual spray flow rate, and number of installed units differed between the water spray unit 91 and the chemical spray unit 92 because the spray volume of water W and the spray volume of chemical C were different. The number of nozzles used also changed depending on whether water was supplied or chemical aqueous solution was supplied, making it difficult to uniformly spray the defrosting liquid mixed in the tower under both conditions. In contrast, in the defrosting tower 20 according to the present invention, since multiple spray units 22 spray either water W or chemical aqueous solution D as the defrosting liquid in the same way, the rated flow rate and actual spray capacity can be made uniform regardless of the number installed. Therefore, as shown in Figure 3, the spray nozzles 22b of the spray units 22 can be evenly distributed regardless of the number of spray units 22 installed. As a result, the chemical aqueous solution D can be sprayed even more uniformly within the defrosting tower 20.

[0080] Furthermore, as mentioned above, conventional cooling towers 90 required manual removal and reinstallation of the chemical spraying unit 92 for maintenance, etc. However, the cooling tower 20 according to the present invention is configured as described above, allowing the series of operations to be controlled by the control unit 12 of the cooling liquid supply device 10. In other words, once the operator sets the HCl·SOx concentration, the control unit 12 controls each device so that the HCl·SOx concentration in the exhaust gas G is always kept below the set value, and this is automatically controlled.

[0081] In this embodiment, examples of acidic toxic gases are HCl (hydrogen chloride) and SOx (sulfur oxide), and their concentrations are measured and used as control amounts. However, the acidic toxic gases are not limited to these, and other examples of acidic toxic gases may be used, for example, by measuring the concentration of either HCl or SOx and using it as a control amount. [Explanation of symbols]

[0082] G exhaust gas W water C. Drugs D. Drug solution 1 Dilution tank 2 Storage tank 3 Water supply section 4. Drug Supply Department 5. First liquid supply channel 5b Inverted U-shaped tube section 6. Second liquid supply channel 7 Supply route 10 Reduced temperature liquid supply device 11. Acid gas concentration acquisition unit 12 Control Unit 13. Dilution level acquisition unit 14 Reservoir liquid level acquisition part VW water supply valve Vc drug supply valve V1 First Valve V2 2nd valve 20 Defrosting tower 21 Torso 22 Spray part (injection part) 22b Spray nozzle 100 Waste Treatment Facilities

Claims

1. A cooling tower that reduces the temperature of exhaust gas produced when a material is heat-treated, The cooling tower is A body section formed in which an internal space is created through which exhaust gases pass from bottom to top, An injection unit that sprays a cooling liquid supplied from the outside of the body into the internal space, A cooling liquid supply device that supplies cooling liquid to the injection unit and Equipped with, The cooling solution is water, or an aqueous solution of the drug diluted with water. The detemperature-reducing liquid supply device is A dilution tank for diluting the drug into an aqueous solution of the required dilution concentration, A water supply unit capable of supplying water to the dilution tank, A chemical supply unit capable of supplying chemicals to a dilution tank, A storage tank into which the detemperatureized liquid is supplied from the dilution tank and stored, A first liquid supply channel capable of supplying water above a predetermined liquid level in the dilution tank to the storage tank, A second liquid supply channel that allows the drug aqueous solution to be supplied from the bottom of the dilution tank to the storage tank, A supply path that supplies a cooling liquid from the storage tank to the injection unit. It has, The storage tank has a larger capacity than the dilution tank. In the water supply state, where water is supplied as a temperature-reducing liquid, water is supplied to the injection unit via a dilution tank, a first liquid supply channel, a storage tank, and a supply channel. A de-cooling tower characterized in that, in the state of supplying a drug aqueous solution as a de-cooling liquid, the drug aqueous solution is supplied to the injection section via a dilution tank, a second liquid supply channel, a storage tank, and a supply channel.

2. An acid hazardous gas concentration acquisition unit that acquires the concentration of acid hazardous gases in exhaust gas as the measured acid hazardous gas concentration, A control unit capable of switching between a water supply state and a chemical solution supply state. It has, The defroster according to claim 1, characterized in that the control unit switches between a water supply state and a chemical aqueous solution supply state based on the result of comparing the measured acid gas concentration value with a predetermined set value.

3. It has a dilution level acquisition unit that acquires the liquid level in the dilution tank as the measured dilution level, The defroster according to claim 2, characterized in that the control unit adjusts the supply amounts of drug and water by the drug supply unit and the water supply unit so that a predetermined amount of drug and a predetermined amount of water corresponding to the required dilution concentration are supplied, based on the measured dilution level value.

4. A cooling tower according to any one of claims 1 to 3, It is further equipped with a dust collector that is connected to the cooling tower by a connecting passage and removes dust from the exhaust gas discharged from the cooling tower. An exhaust gas treatment system characterized in that a neutralizing agent for neutralizing acidic harmful gases is supplied in a connecting passage or dust collector.

5. The exhaust gas treatment equipment described in claim 4 is provided, It is further equipped with an incinerator for burning the materials to be processed, A cooling tower is a type of incineration facility characterized by its ability to lower the temperature of exhaust gases discharged from the incinerator.

6. A method for supplying a cooling liquid in a cooling tower, which uses a cooling liquid to lower the temperature of exhaust gas produced when a workpiece is heat-treated, The cooling tower is A body section formed in which an internal space is created through which exhaust gases pass from bottom to top, An injection unit that sprays a cooling liquid supplied from the outside of the body into the internal space, A dilution tank in which the drug is diluted, A water supply unit capable of supplying water to the dilution tank, A chemical supply unit capable of supplying chemicals to a dilution tank, A storage tank for storing the reduced-temperature liquid from the dilution tank and Equipped with, The cooling solution is water, or an aqueous solution of the drug diluted with water. The storage tank has a larger capacity than the dilution tank. The water supply conditions for supplying water to the cooling tower include: Water is supplied to the dilution tank. Water above a predetermined liquid level in the dilution tank is sent to the storage tank. The pumped water is supplied from the storage tank to the injection unit. The chemical solution supply condition for supplying the chemical solution to the detemperature tower is: The chemical and water are supplied to the dilution tank. The drug is diluted in a dilution tank to an aqueous solution of the required dilution concentration. The aqueous solution of the drug is sent from the bottom of the dilution tank to the storage tank. A method for supplying a temperature-reducing liquid, characterized in that the delivered aqueous drug solution is supplied from a storage tank to an injection unit.

7. The concentration of acidic harmful gases in the exhaust gas is obtained as the measured acidic gas concentration. The method for supplying a de-icing liquid according to claim 6, characterized in that the water supply state and the chemical aqueous solution supply state are switched based on the result of comparing the measured acid gas concentration value with a predetermined set value.

8. The method for supplying a cooling liquid according to claim 7, characterized in that, while the supply of the cooling liquid to the cooling tower continues, the amount of cooling liquid stored in the storage tank is adjusted so that some cooling liquid remains in the storage tank when the dilution of the chemical agent is completed in the dilution tank.

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