Ammonia removal device and method

Abstract

This ammonia removal device for detoxifying an ammonia-containing gas which has pressure higher than atmospheric pressure in an ammonia supply system comprises: a storage tank which stores a removal liquid for ammonia and which has a discharge port at a top part thereof; a water spray nozzle which is opened in a gas phase part in a space in the vertical direction between the discharge port and a liquid surface of the removal liquid in the storage tank; an underwater nozzle which is opened in the removal liquid; an air nozzle which is opened in the gas phase part; and an ammonia-containing gas system through which the ammonia-containing gas flows from the ammonia supply system to the underwater nozzle and the air nozzle.

Description

Ammonia detoxification device and method

[0001] The present disclosure relates to an ammonia abatement device and method for removing ammonia components from an ammonia-containing gas.

[0002] Conventionally, facilities that use ammonia have been equipped with an ammonia abatement device, and an ammonia-containing gas is released into the atmosphere after the ammonia component is separated and removed in the ammonia abatement device. Patent Document 1 discloses this type of ammonia abatement device.

[0003] The ammonia detoxification device disclosed in Patent Document 1 includes a storage tank storing an aqueous sulfuric acid solution as an ammonia absorption liquid, a vent stack disposed at the top of the storage tank, and an ammonia-containing gas injection pipe having an inlet disposed at the bottom of the storage tank. When an ammonia-containing gas is injected into the bottom of the storage tank through the ammonia-containing gas injection pipe, the ammonia in the gas is absorbed and removed by the absorption liquid. The gas from which the ammonia has been removed is released into the atmosphere through the vent stack.

[0004] Japanese Patent Application Laid-Open No. 2001-239130

[0005] In a configuration in which ammonia-containing gas sent through a pipe to an ammonia detoxification device is released into the atmosphere after the ammonia component is removed in a detoxification tank storing an ammonia detoxification liquid, when the inflow of new ammonia-containing gas into the pipe stops, the pressure inside the pipe gradually decreases and eventually converges to a pressure equivalent to the pressure at the ammonia-containing gas inlet in the detoxification tank. The ammonia-containing gas inlet in the detoxification tank is in the detoxification liquid, so it is higher than atmospheric pressure. As a result, even after the release into the atmosphere from the ammonia detoxification device is completed, the pressure inside the pipe remains higher than atmospheric pressure. In other words, the pressure inside the pipe is higher than atmospheric pressure, and there remains a risk of ammonia-containing gas leaking from the pipe.

[0006] The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide a technology for suppressing leakage of ammonia-containing gas remaining in piping after the release into the atmosphere is completed, in a configuration in which ammonia-containing gas is sent to an ammonia detoxification device through piping and then released into the atmosphere after the ammonia component is removed by the detoxification device.

[0007] In order to solve the above problems, an ammonia detoxification device according to one aspect of the present disclosure is an ammonia detoxification device that detoxifies an ammonia-containing gas at a pressure higher than atmospheric pressure in an ammonia supply system, and includes: a storage tank that stores an ammonia detoxification liquid and has an outlet at its top; a sprinkler nozzle that opens into a gas phase portion vertically between the liquid level of the detoxification liquid in the storage tank and the outlet; an underwater nozzle that opens into the detoxification liquid; an air nozzle that opens into the gas phase portion; and an ammonia-containing gas system through which the ammonia-containing gas flows from the ammonia supply system to the underwater nozzle and the air nozzle.

[0008] In order to solve the above problems, an ammonia detoxification method according to one embodiment of the present disclosure is a method for detoxifying ammonia-containing gas at a pressure higher than atmospheric pressure in an ammonia supply system, comprising: injecting the ammonia-containing gas into ammonia detoxification liquid in a storage tank storing the ammonia detoxification liquid through a submerged injection pipe connected to the ammonia supply system; spraying water into a gas phase portion vertically between the liquid level of the detoxification liquid in the storage tank and a discharge port at the top of the storage tank; and injecting the ammonia-containing gas into contact with the water sprayed into the gas phase portion through an air injection pipe connected to the ammonia supply system.

[0009] According to the present disclosure, in a configuration in which ammonia-containing gas sent through piping to an ammonia detoxification device is released into the atmosphere after the ammonia components are removed in the detoxification device, leakage of ammonia-containing gas remaining in the piping after the release into the atmosphere is completed can be suppressed.

[0010] Fig. 1 is a schematic configuration diagram of an ammonia supply system equipped with an ammonia detoxification device according to an embodiment of the present disclosure. Fig. 2 is a schematic configuration diagram of an ammonia detoxification device according to an embodiment of the present disclosure. Fig. 3 is a schematic configuration diagram of an ammonia detoxification device according to Modification 1. Fig. 4 is a schematic configuration diagram of an ammonia detoxification device according to Modification 2. Fig. 5 is a timing chart of an ammonia detoxification process.

[0011] Next, an embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram of an ammonia supply system 100 equipped with an ammonia detoxification device 2 according to an embodiment of the present disclosure.

[0012] 1 is a flow path for an ammonia-containing gas to be supplied to the ammonia combustion burner 5, and is composed of piping and the like. The ammonia combustion burner 5 is an example of an ammonia-using device, and the ammonia-using device is not limited to the ammonia combustion burner 5. In addition, the ammonia-containing gas may be any gas containing ammonia, and the concentration of ammonia in the ammonia-containing gas is not limited.

[0013] The ammonia supply system 100 includes a supply header 13 connected to a gas source 12, and a shutoff valve 16 is disposed in the supply header 13 for opening and closing the flow path of the supply header 13. One or more supply branch pipes 14 are connected to the supply header 13 downstream of the shutoff valve 16. The supply branch pipes 14 are connected to an ammonia combustion burner 5, and the ammonia-containing gas that flows from the supply header 13 into the supply branch pipe 14 is supplied to the ammonia combustion burner 5. The supply branch pipe 14 is disposed with a burner valve 17 for opening and closing the flow path of the supply branch pipe 14.

[0014] A release pipe 15 is connected to the supply main pipe 13 downstream of the shutoff valve 16. The release pipe 15 is used when releasing the ammonia-containing gas remaining in the ammonia supply system 100. A release valve 18 is disposed in the release pipe 15 to open and close the flow path of the release pipe 15. An ammonia detoxification device 2 is connected to the most downstream of the release pipe 15.

[0015] In the ammonia supply system 100 having the above configuration, when an ammonia-containing gas is being supplied to the ammonia combustion burner 5, the shutoff valve 16 and the burner valve 17 are opened and the release valve 18 is closed. When the supply of the ammonia-containing gas to the ammonia combustion burner 5 is stopped, the shutoff valve 16 and the burner valve 17 are closed and the release valve 18 is opened.

[0016] When the ammonia supply system 100 switches from supplying ammonia-containing gas to stopping the supply, ammonia-containing gas at a pressure higher than atmospheric pressure remains in the portion of the supply main pipe 13 downstream of the shutoff valve 16 and in the portion of the supply branch pipe 14 upstream of the burner valve 17. When the release valve 18 is opened, this ammonia-containing gas flows through the release pipe 15 to the ammonia detoxification device 2. In the ammonia detoxification device 2, ammonia is removed from the ammonia-containing gas, and the ammonia-detoxified gas is released into the atmosphere.

[0017] <Configuration of Ammonia Detoxification Apparatus 2> Here, a detailed description will be given of the configuration of the ammonia detoxification apparatus 2. Fig. 2 is a schematic configuration diagram of the ammonia detoxification apparatus 2 according to one embodiment of the present disclosure.

[0018] The ammonia detoxification device 2 shown in Figure 2 comprises a storage tank 21 in which an ammonia detoxification liquid 22 is stored, spray nozzles 31, 32 that spray water into the gas phase portion 24 of the storage tank 21, submerged nozzles 46A, 46B that spray an ammonia-containing gas into the detoxification liquid 22, an air nozzle 47 that blows the ammonia-containing gas into the gas phase portion 24 of the storage tank 21, and an ammonia-containing gas system 4 in which the ammonia-containing gas flows from a discharge pipe 15 to the submerged nozzles 46A, 46B and the air nozzle 47.

[0019] The detoxifying liquid 22 stored in the storage tank 21 is a liquid that traps ammonia, and is, for example, a sulfuric acid aqueous solution. When the ammonia-containing gas is blown into the detoxifying liquid 22, the ammonia in the ammonia-containing gas is absorbed into the detoxifying liquid 22 by the following reaction: NH ３ +H ２ O → NH ４ OH 2NH ４ OH+H ２ SO ４ → (NH ４ ) ２ SO ４ +2H ２ O

[0020] An outlet 25 opens at the top of the storage tank 21. Within the storage tank 21, a gas phase 24 is present between the liquid surface 23 of the abatement liquid 22 and the outlet 25 in the vertical direction. The gas phase 24 is in communication with the outside through the outlet 25, and is at approximately atmospheric pressure. The gas from which the ammonia component has been removed in the gas phase 24 is released from the storage tank 21 into the atmosphere through the outlet 25.

[0021] The first sprinkler nozzle 31 is disposed in the gas phase section 24 of the storage tank 21. The first sprinkler nozzle 31 is preferably disposed in the upper half of the gas phase section 24, more preferably directly below the discharge port 25. A water supply pipe 30 is connected to the first sprinkler nozzle 31. Water supplied to the first sprinkler nozzle 31 through the water supply pipe 30 is sprinkled from the first sprinkler nozzle 31 into the gas phase section 24. The first sprinkler nozzle 31 is preferably a nozzle that sprays water so as to diffuse it over a wide area. The water sprayed from the first sprinkler nozzle 31 comes into contact with ammonia gas floating in the gas phase section 24, absorbs the ammonia, and becomes ammonia water in which the ammonia is dissolved, which falls into the abatement liquid 22.

[0022] 2, the submerged nozzles 46A, 46B include a first submerged nozzle 46A and a second submerged nozzle 46B that open at different height levels within the detoxifying liquid 22. At least one first submerged nozzle 46A is located at the bottom of the storage tank 21. At least one second submerged nozzle 46B is located below the liquid level 23 of the storage tank 21 and above the first submerged nozzle 46A. However, the ammonia detoxifying device 2 only needs to have at least one submerged nozzle 46A, 46B that opens into the detoxifying liquid 22, and may also have three or more submerged nozzles.

[0023] The ammonia-containing gas system 4 is composed of a main pipe 40 connected to the release pipe 15 of the ammonia supply system 100, and blowing pipes 41, 42 connected to the main pipe 40. Ammonia-containing gas flows into the main pipe 40 from the release pipe 15. By opening and closing a release valve 18 provided in the release pipe 15, it is possible to switch between allowing and stopping the inflow of ammonia-containing gas from the release pipe 15 to the main pipe 40. The release valve 18 may be provided in the main pipe 40. Furthermore, the main pipe 40 may be a part of the release pipe 15.

[0024] The blowing pipes 41, 42 include a submerged blowing pipe 41 that blows the ammonia-containing gas into the abatement liquid 22 and an air blowing pipe 42 that blows the ammonia-containing gas into the gas phase 24. The submerged blowing pipe 41 includes a first submerged blowing pipe 41A connected to a first submerged nozzle 46A and a second submerged blowing pipe 41B connected to a second submerged nozzle 46B. The ammonia-containing gas flows from the main pipe 40 through the first submerged blowing pipe 41A to the first submerged nozzle 46A and is blown out from the first submerged nozzle 46A into the abatement liquid 22. The ammonia-containing gas also flows from the discharge pipe 15 through the second submerged blowing pipe 41B to the second submerged nozzle 46B and is blown out from the second submerged nozzle 46B into the abatement liquid 22.

[0025] At least one of the first submerged nozzle 46A and the second submerged nozzle 46B may be equipped with a fine bubble generator. The fine bubble generator generates fine bubbles with diameters on the order of microns or less. Fine bubbles of ammonia-containing gas are blown out from the first submerged nozzle 46A and the second submerged nozzle 46B equipped with the fine bubble generator. Fine bubbles have a smaller diameter than millibubbles and rise slowly in the abatement liquid 22. The fine bubbles of ammonia-containing gas have a larger contact area with the abatement liquid 22 and a longer contact time, accelerating the reaction between the ammonia contained in the ammonia-containing gas and the abatement liquid 22.

[0026] The first and second submersible blowing pipes 41A and 41B, as well as the first and second submersible nozzles 46A and 46B, are desirably made of a highly corrosion-resistant material, since they are constantly submerged in the abatement liquid 22. Stainless steel is an example of such a material.

[0027] At least one air nozzle 47 is arranged above the liquid level 23 of the storage tank 21 and below the discharge port 25. A second sprinkler nozzle 32 connected to the water supply pipe 30 is arranged near the air nozzle 47. Water supplied to the second sprinkler nozzle 32 through the water supply pipe 30 is sprinkled from the second sprinkler nozzle 32 into the gas phase section 24. The air nozzle 47 is connected to the main pipe 40 via an air blowing pipe 42. The ammonia-containing gas flows from the main pipe 40 through the air blowing pipe 42 to the air nozzle 47 and is blown out from the air nozzle 47 into the gas phase section 24.

[0028] The aerial nozzle 47 is positioned so that the ammonia-containing gas sprayed from the aerial nozzle 47 collides with and mixes with the water sprayed from the second watering nozzle 32. Because the ammonia in the ammonia-containing gas sprayed from the aerial nozzle 47 rises in the gas phase section 24, it is desirable that the aerial nozzle 47 open lower than the first watering nozzle 31 and the second watering nozzle 32. However, the second watering nozzle 32 may be omitted, and the aerial nozzle 47 may be positioned so that the ammonia-containing gas sprayed from the aerial nozzle 47 collides with the water sprayed from the first watering nozzle 31. Alternatively, the aerial nozzle 47 may be a nozzle with a mixer configured to mix and spray the ammonia-containing gas supplied from the aerial blowing pipe 42 and the water supplied from the water supply pipe 30.

[0029] Of the first submerged nozzle 46A, the second submerged nozzle 46B, and the aerial nozzle 47, the first submerged nozzle 46A has the highest ammonia removal efficiency from the ammonia-containing gas. Therefore, the relationship between at least one of the pipe diameter of the blowing pipe, the nozzle outlet area (i.e., caliber), and the number of nozzles is adjusted so that the ammonia-containing gas flows preferentially to the first submerged nozzle 46A. For example, the first submerged blowing pipe 41A, the second submerged blowing pipe 41B, and the aerial blowing pipe 42 have different pipe diameters, with the pipe diameters decreasing in the order of the first submerged blowing pipe 41A > the second submerged blowing pipe 41B > the aerial blowing pipe 42. For example, the first submerged nozzle 46A, the second submerged nozzle 46B, and the aerial nozzle 47 have different total outlet areas, with the total outlet area decreasing in the order of the first submerged nozzle 46A > the second submerged nozzle 46B > and the aerial nozzle 47. The total outlet area of ​​the first submerged nozzles 46A means the sum of the outlet areas of all the first submerged nozzles 46A connected to the first submerged blowing pipe 41A. The same applies to the total outlet area of ​​the second submerged nozzles 46B and the total outlet area of ​​the aerial nozzles 47. For example, the numbers of the first submerged nozzles 46A, second submerged nozzles 46B, and aerial nozzles 47 are different from one another, with the number of nozzles decreasing in the order of first submerged nozzles 46A > second submerged nozzles 46B > aerial nozzles 47.

[0030] <<Ammonia Detoxification Method>> Here, a description will be given of an ammonia detoxification method using the above-described ammonia detoxification device 2. In the ammonia supply system 100, when the shutoff valve 16 and the burner valve 17 (see FIG. 1 ) are closed and the release valve 18 is opened, the ammonia-containing gas remaining in the ammonia supply system 100 and having a pressure higher than atmospheric pressure flows into the mother pipe 40.

[0031] Most of the ammonia-containing gas that flows into the header pipe 40 passes through the first submerged injection pipe 41A and the second submerged injection pipe 41B and is sprayed into the abatement liquid 22 from the submerged nozzles 46A and 46B, respectively. The ammonia-containing gas sprayed into the abatement liquid 22 from the submerged nozzles 46A and 46B reacts with the abatement liquid 22 as it rises toward the liquid surface 23, removing ammonia. The gas from which the ammonia has been removed passes through the liquid surface 23 and moves to the gas phase 24. In this way, most of the ammonia in the ammonia-containing gas sprayed into the abatement liquid 22 is absorbed by the abatement liquid 22. Some ammonia may remain in the gas that moves from the abatement liquid 22 to the gas phase 24. Because ammonia is lighter than air, the ammonia in the gas phase 24 rises and comes into contact with the water sprayed from the first spray nozzle 31, dissolves in the water, and becomes ammonia water, which then falls into the abatement liquid 22. The gas from which the ammonia has been removed is released into the atmosphere through the outlet 25.

[0032] The remainder of the ammonia-containing gas that has flowed into the main pipe 40 passes through the air blowing pipe 42 and is blown out from the air nozzle 47 into the gas phase section 24. The ammonia-containing gas blown into the gas phase section 24 from the air nozzle 47 comes into contact with the water sprayed out from the second sprinkler nozzle 32 (or the first sprinkler nozzle 31), dissolves in the water, and becomes ammonia water, which falls into the abatement liquid 22.

[0033] As described above, while the ammonia-containing gas is being detoxified in the ammonia detoxification device 2, no new ammonia-containing gas flows into the discharge pipe 15, so the pressure inside the discharge pipe 15 gradually decreases. First, when the pressure inside the discharge pipe 15 decreases to the water pressure at the outlet of the first submerged nozzle 46A, the injection of ammonia-containing gas from the first submerged nozzle 46A stops. Next, when the pressure inside the discharge pipe 15 decreases to the water pressure at the outlet of the second submerged nozzle 46B, the injection of ammonia-containing gas from the second submerged nozzle 46B stops. Finally, when the pressure inside the discharge pipe 15 decreases to the air pressure at the outlet of the air nozzle 47, i.e., atmospheric pressure, the injection of ammonia-containing gas from the air nozzle 47 stops. Thus, even after the injection of ammonia-containing gas from the first submerged nozzle 46A and the second submerged nozzle 46B stops, the injection of ammonia-containing gas from the air nozzle 47 into the storage tank 21 continues until the pressure inside the discharge pipe 15 reaches atmospheric pressure. In this way, the pressure inside the discharge pipe 15 can be automatically lowered to atmospheric pressure without relying on the power of a blower, etc. When the pressure inside the discharge pipe 15 reaches atmospheric pressure, leakage of gas into the atmosphere from the discharge pipe 15, the connection between the discharge pipe 15 and the main pipe 40, the connection between the main pipe 40 and each blowing pipe, etc. is suppressed.

[0034] [Modifications] Modifications 1 and 2 of the ammonia detoxification apparatus 2 according to the above embodiment will be described. The ammonia detoxification apparatus 2 according to Modifications 1 and 2 differ from the ammonia detoxification apparatus 2 according to the above embodiment in that the flow path of the ammonia-containing gas is operated by a valve so that the nozzle from which the ammonia-containing gas is blown out can be selected from the first submerged nozzle 46A, the second submerged nozzle 46B, and the air nozzle 47. In the description of the modifications, components that are the same as or similar to those in the above embodiment are denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted.

[0035] Figure 3 is a schematic diagram of an ammonia detoxification apparatus 2 according to Modification 1. In the ammonia detoxification apparatus 2 according to Modification 1 shown in Figure 3, the second submerged blowing pipe 41B is provided with a first valve 51 that opens and closes the flow path of the second submerged blowing pipe 41B. The air blowing pipe 42 is provided with a second valve 52 that opens and closes the flow path of the air blowing pipe 42. The water supply pipe 30 is provided with a sprinkler valve 53. The discharge pipe 15 is provided with a pressure sensor 55 that detects the pressure inside the pipe.

[0036] Fig. 4 is a schematic configuration diagram of an ammonia detoxification device 2 according to Modification 2. The ammonia detoxification device 2 according to Modification 2 shown in Fig. 4 differs from the embodiment and Modification 1 in that a control device 60 operates a flow path for an ammonia-containing gas with a valve.

[0037] In the ammonia detoxification apparatus 2 shown in Figure 4, the second submerged blowing pipe 41B is provided with a first valve 51 that opens and closes the flow path of the second submerged blowing pipe 41B. The air blowing pipe 42 is provided with a second valve 52 that opens and closes the flow path of the air blowing pipe 42. The water supply pipe 30 is provided with a sprinkler valve 53 that switches the supply of water to the first sprinkler nozzle 31 and the second sprinkler nozzle 32 on and off. The first valve 51, the second valve 52, the release valve 18, and the sprinkler valve 53 are electrically connected to a control device 60, and these valves open and close in response to commands from the control device 60. The release pipe 15 is provided with a pressure sensor 55 that detects the pressure inside the pipe. The pressure sensor 55 is electrically connected to the control device 60, and the control device 60 opens and closes the valve based on the detection value of the pressure sensor 55 to operate the flow path of the ammonia-containing gas.

[0038] <Ammonia Detoxification Method> Here, the ammonia detoxification methods using the ammonia detoxification device 2 according to Modifications 1 and 2 will be described with reference to the ammonia detoxification timing chart of Figure 5. The ammonia detoxification methods are common to Modifications 1 and 2, but in Modification 1, each valve is manually opened and closed, whereas in Modification 2, the opening and closing operations of each valve are controlled by a control device 60. Although not specifically indicated, in the ammonia detoxification method using the ammonia detoxification device 2 according to Modification 2, the opening and closing operations of the first valve 51, the second valve 52, the release valve 18, and the sprinkler valve 53 are controlled by the control device 60, and the control device 60 is configured to monitor the detection value of the pressure sensor 55 during treatment and issue operation commands to each valve based on the detection value.

[0039] In the ammonia supply system 100, when the process of releasing the ammonia-containing gas is started based on the purge command being turned ON, the shutoff valve 16 and the burner valve 17 (see FIG. 1 ) are closed and the release valve 18 is opened. As a result, the ammonia-containing gas remaining in the ammonia supply system 100 and having a pressure higher than atmospheric pressure flows into the main pipe 40 through the release pipe 15. With the opening of the release valve 18, the sprinkler valve 53 is opened. With the opening of the sprinkler valve 53, sprinkling of water from the first sprinkler nozzle 31 and the second sprinkler nozzle 32 is started.

[0040] The first valve 51 and the second valve 52 are closed in advance. Therefore, immediately after the start of purging of the ammonia-containing gas, the ammonia-containing gas flows only into the first submerged blowing pipe 41A, and is blown out from the first submerged nozzle 46A into the abatement liquid 22. At this time, blowing of the ammonia-containing gas from the second submerged nozzle 46B and the aerial nozzle 47 is stopped.

[0041] As the ammonia detoxification process progresses in the ammonia detoxification device 2, when the internal pressure of the discharge pipe 15 detected by the pressure sensor 55 falls below the first pressure threshold P1, the first valve 51 opens. Let Hd be the height from the first submerged nozzle 46A to the liquid level 23, Hs be the height from the second submerged nozzle 46B to the liquid level 23, ρ be the density of the detoxification liquid 22, and g be the gravitational acceleration. ρ, g, Hd, and Hs are known or controlled values ​​that are pre-set in the control device 60. The water pressure at the outlet of the first submerged nozzle 46A is represented by ρgHd, and the water pressure at the outlet of the second submerged nozzle 46B is represented by ρgHs. The first pressure threshold P1 is ρgHd × n1, where n1 is a variable between 1 and 1.1. In other words, the first pressure threshold P1 is equal to or slightly higher than the water pressure at the outlet of the first submerged nozzle 46A. The control device 60 can calculate the first pressure threshold P1 using a given value of n1. The value of n1 may be stored in advance in a memory connected to the control device 60, input at the appropriate time via an input device connected to the control device 60, or sent to the control device 60 remotely via a communication line.

[0042] When the first valve 51 is opened, the ammonia-containing gas is blown out from the second submerged nozzle 46B through the second submerged blowing pipe 41B into the abatement liquid 22. As the pressure inside the discharge pipe 15 of the ammonia supply system 100 further drops, the blowing of the ammonia-containing gas from the first submerged nozzle 46A automatically stops. However, to prevent backflow of the abatement liquid 22 into the first submerged blowing pipe 41A, an additional on-off valve may be provided in the first submerged blowing pipe 41A, and the on-off valve may be closed to forcibly stop the blowing of the ammonia-containing gas from the first submerged nozzle 46A.

[0043] As the ammonia-containing gas detoxification process progresses further in the ammonia detoxification device 2, when the pressure inside the discharge pipe 15 of the ammonia supply system 100, detected by the pressure sensor 55, falls below the second pressure threshold P2, the first valve 51 is closed and the second valve 52 is opened. The second pressure threshold P2 is expressed as ρgHs×n2, where n2 is a variable between 1 and 1.1. In other words, the second pressure threshold P2 is equal to or slightly higher than the water pressure at the outlet of the second submerged nozzle 46B. The control device 60 can calculate the second pressure threshold P2 using a given value of n2. The value of n2 may be pre-stored in a memory connected to the control device 60, input as needed via an input device connected to the control device 60, or remotely transmitted to the control device 60 via a communication line.

[0044] When the second valve 52 is opened, the ammonia-containing gas is blown out from the air nozzle 47 through the air blowing pipe 42 into the gas phase section 24. In order to prevent backflow of the abatement liquid 22 into the second submerged blowing pipe 41B, the first valve 51 is closed to forcibly stop the blowing of the ammonia-containing gas from the second submerged nozzle 46B.

[0045] When the pressure inside the release pipe 15 drops to the air pressure at the outlet of the air nozzle 47, i.e., atmospheric pressure, the blowing of the ammonia-containing gas from the air nozzle 47 automatically stops. After the pressure inside the release pipe 15 drops to atmospheric pressure, the release valve 18 and the second valve 52 are closed, and then the sprinkler valve 53 is closed, and the release process ends.

[0046] As described above, in the ammonia detoxification devices 2 according to the first and second modifications, the flow path of the ammonia-containing gas is operated by a valve, and as the pressure inside the discharge pipe 15 decreases, the nozzle that blows out the ammonia-containing gas is switched in this order from the first submerged nozzle 46A, the second submerged nozzle 46B, and the air nozzle 47. This increases the proportion of the ammonia-containing gas being treated that is blown out from the first submerged nozzle 46A as much as possible, thereby enabling efficient ammonia detoxification.

[0047] [Summary] The ammonia detoxification device 2 according to the first item of the present disclosure is an ammonia detoxification device 2 that detoxifies an ammonia-containing gas at a higher pressure than atmospheric pressure in an ammonia supply system 100, and comprises: a storage tank 21 that stores an ammonia detoxification liquid 22 and has an outlet 25 at its top; sprinkler nozzles 31, 32 that open into a gas phase section 24 between a liquid level 23 of the detoxification liquid 22 in the storage tank 21 and the outlet 25 in the vertical direction; submerged nozzles 46A, 46B that open into the detoxification liquid 22; an air nozzle 47 that opens into the gas phase section 24; and an ammonia-containing gas system 4 that supplies ammonia-containing gas from the ammonia supply system 100 to the submerged nozzles 46A, 46B and the air nozzle 47.

[0048] In the ammonia abatement apparatus 2 configured as described above, the ammonia-containing gas in the ammonia supply system 100 is sprayed out from both the submerged nozzles 46A, 46B and the aerial nozzle 47. The ammonia-containing gas sprayed out from the submerged nozzles 46A, 46B into the abatement liquid 22 has the ammonia contained therein absorbed and separated into the abatement liquid 22 as it rises through the abatement liquid 22, and the gas from which the ammonia has been removed flows into the gas phase 24 and is released into the atmosphere through the outlet 25. The ammonia-containing gas sprayed out from the aerial nozzle 47 into the gas phase 24 mixes with water sprayed out from the spray nozzles 31, 32, and the ammonia dissolves in the water to become ammonia water, which falls into the abatement liquid 22, and the gas from which the ammonia has been removed is released into the atmosphere through the outlet 25. As the ammonia detoxification process progresses in this way, after the pressure inside the ammonia supply system 100 (in the embodiment, the release pipe 15) drops below the pressure at the outlets of the submerged nozzles 46A, 46B, the blowing of the ammonia-containing gas from the submerged nozzles 46A, 46B stops, but blowing from the aerial nozzle 47 continues until the pressure inside the pipe of the ammonia supply system 100 reaches atmospheric pressure, and when the pressure inside the pipe of the ammonia supply system 100 reaches atmospheric pressure, the flow of the ammonia-containing gas into the storage tank 21 and the release of the detoxified gas to the atmosphere end. Therefore, after the release to the atmosphere is completed, the pressure inside the pipes of the ammonia supply system 100 and the ammonia-containing gas system 4 connected to the ammonia supply system 100 is approximately the same as atmospheric pressure, and leakage of the ammonia-containing gas remaining in these pipes to the outside is suppressed.

[0049] The ammonia detoxification device 2 relating to the second item of the present disclosure is the ammonia detoxification device 2 relating to the first item, in which the underwater nozzles 46A, 46B include a first underwater nozzle 46A that opens to the bottom of the storage tank 21 and a second underwater nozzle 46B that opens between the first underwater nozzle 46A and the liquid surface 23 of the detoxification liquid 22 in the vertical direction.

[0050] In the ammonia detoxification device 2 configured as described above, the second submerged nozzle 46B continues to blow out the ammonia-containing gas even after the first submerged nozzle 46A stops blowing out the ammonia-containing gas. Therefore, compared to a system equipped with only the first submerged nozzle 46A, a larger amount of the ammonia-containing gas can be blown out into the detoxification liquid 22, thereby improving the efficiency of the ammonia detoxification process.

[0051] The ammonia detoxification device 2 according to the third item of the present disclosure is the ammonia detoxification device 2 according to the second item, in which the total nozzle outlet area of ​​the submerged nozzles 46A, 46B and the aerial nozzle 47 that open at the same vertical height is smaller the higher they are positioned in the vertical direction.

[0052] According to the ammonia detoxification device 2 having the above-described configuration, the ammonia-containing gas is more likely to be blown out from the nozzles arranged lower in the vertical direction, and the ammonia-containing gas is preferentially blown out from the nozzles arranged lower in the vertical direction.

[0053] The ammonia detoxification device 2 according to the fourth item of the present disclosure is an ammonia detoxification device 2 according to any one of the first to third items, in which the underwater nozzles 46A, 46B are equipped with fine bubble generators that atomize the ammonia-containing gas that is blown out.

[0054] In the ammonia detoxification device 2 configured as described above, the bubbles of ammonia-containing gas blown out from the underwater nozzles 46A, 46B into the detoxification liquid 22 are made finer, and the efficiency of the ammonia detoxification treatment can be improved by increasing the contact area between the ammonia-containing gas and the detoxification liquid 22 and increasing the residence time of the ammonia-containing gas in the detoxification liquid 22.

[0055] The ammonia detoxification device 2 relating to the fifth item of the present disclosure is an ammonia detoxification device 2 relating to any of the first to fourth items, in which the aerial nozzle 47 is arranged so as to spray ammonia-containing gas toward the water sprayed from the sprinkler nozzles 31, 32.

[0056] In the ammonia detoxification device 2 having the above configuration, the ammonia-containing gas blown into the gas phase section 24 is immediately mixed with the water blown out from the water spray nozzles 31, 32, and the ammonia in the ammonia-containing gas is dissolved in the water and separated from the ammonia-containing gas. Therefore, the efficiency of the ammonia detoxification treatment can be improved.

[0057] The ammonia detoxification device 2 according to the sixth item of the present disclosure is an ammonia detoxification device 2 according to any one of the first to fourth items, in which the air nozzle 47 is configured to mix the ammonia-containing gas with water and spray it out.

[0058] In the ammonia detoxification device 2 having the above configuration, the ammonia-containing gas is mixed with water such as spray water and then blown out into the gas phase section 24, so that the ammonia in the ammonia-containing gas is immediately dissolved in the water and separated from the ammonia-containing gas, thereby improving the efficiency of the ammonia detoxification treatment.

[0059] The ammonia detoxification apparatus 2 according to the seventh item of the present disclosure is an ammonia detoxification apparatus 2 according to any one of the first to sixth items, wherein the ammonia-containing gas system 4 includes a main pipe 40 connected to the ammonia supply system 100, submerged injection pipes 41A, 41B connecting the main pipe 40 to submerged nozzles 46A, 46B, and an air injection pipe 42 connecting the main pipe 40 to air nozzle 47.

[0060] The ammonia detoxification device 2 according to the eighth item of the present disclosure is the ammonia detoxification device 2 according to the seventh item, wherein the ammonia-containing gas system 4 includes a first valve 51 that opens and closes the underwater injection pipe 41B and a second valve 52 that opens and closes the air injection pipe 42.

[0061] In the ammonia detoxification device 2 having the above configuration, the nozzle from which the ammonia-containing gas is blown out can be selected by opening and closing the first valve 51 and the second valve 52. Therefore, it is possible to increase the amount of ammonia-containing gas blown out into the detoxification liquid 22, thereby improving the efficiency of the ammonia detoxification treatment.

[0062] The ammonia detoxification device 2 according to the ninth item of the present disclosure is the ammonia detoxification device 2 according to the seventh or eighth item, further comprising a pressure sensor 55 that detects the pressure inside the pipe of the ammonia supply system 100, and a control device 60 that controls the opening and closing operations of the first valve 51 and the second valve 52 based on the pressure inside the pipe detected by the pressure sensor 55, and the control device 60 is configured to switch from a state in which the first valve 51 is opened and the second valve 52 is closed, and ammonia-containing gas is blown out from the underwater nozzle 46B, to a state in which the second valve 52 is opened and the first valve 51 is closed, and ammonia-containing gas is blown out from the air nozzle 47, when the pressure inside the pipe falls below a predetermined pressure threshold P2.

[0063] According to the ammonia detoxification device 2 having the above configuration, the flow path of the ammonia-containing gas is automatically operated by the control device 60 opening and closing the first valve 51 and the second valve 52 so that a larger amount of ammonia-containing gas is blown into the detoxification liquid 22 and the release of the ammonia-containing gas is continued until the pressure inside the pipe of the ammonia supply system 100 reaches atmospheric pressure.

[0064] The ammonia detoxification device 2 according to the tenth item of the present disclosure is the ammonia detoxification device 2 according to the ninth item, wherein the pressure threshold P2 is a value obtained by multiplying the water pressure at the outlet of the underwater nozzle 46B by a variable greater than or equal to 1 and less than or equal to 1.1.

[0065] According to the ammonia detoxification device 2 having the above configuration, the timing at which the nozzle that blows out the ammonia-containing gas is switched from the submerged nozzle 46B to the aerial nozzle 47 can be adjusted by adjusting the variables.

[0066] The ammonia detoxification device 2 according to the eleventh item of the present disclosure is the ammonia detoxification device 2 according to the ninth or tenth item, further comprising a sprinkler valve 53 that switches between supplying and stopping water to the sprinkler nozzles 31, 32, and a release valve 18 that switches between allowing and stopping the inflow of ammonia-containing gas from the ammonia supply system 100, and the control device 60 is configured to control the opening and closing operations of the release valve 18 and the sprinkler valve 53 so that the sprinkler valve 53 opens and closes in conjunction with the opening and closing of the release valve 18.

[0067] According to the ammonia detoxification device 2 having the above-described configuration, it is possible to automatically start sprinkling water into the storage tank 21 in accordance with the inflow of the ammonia-containing gas into the storage tank 21 .

[0068] The ammonia detoxification method according to the twelfth item of the present disclosure is a method for detoxifying ammonia-containing gas at a pressure higher than atmospheric pressure in an ammonia supply system 100, and includes blowing the ammonia-containing gas into ammonia detoxification liquid 22 in a storage tank 21 storing the ammonia detoxification liquid 22 through submerged blowing pipes 41A, 41B connected to the ammonia supply system 100, spraying water into a gas phase portion 24 vertically between a liquid level 23 of the ammonia detoxification liquid 22 in the storage tank 21 and a discharge port 25 at the top of the storage tank 21, and blowing the ammonia-containing gas into the gas phase portion 24 through an air blowing pipe 42 connected to the ammonia supply system 100 so as to come into contact with the water sprayed into the gas phase portion 24.

[0069] According to the above-described ammonia detoxification method, the ammonia-containing gas in the ammonia supply system 100 is blown out both into the detoxification liquid 22 and into the gas phase section 24. The ammonia contained in the ammonia-containing gas blown out into the detoxification liquid 22 is absorbed and separated into the detoxification liquid 22 while the ammonia-containing gas rises through the detoxification liquid 22, and the gas from which the ammonia has been removed flows into the gas phase section 24 and is released into the atmosphere through the outlet 25. The ammonia-containing gas blown out into the gas phase section 24 mixes with the sprayed water, and the ammonia in the ammonia-containing gas is dissolved in the water and separated, and the gas from which the ammonia has been removed is released into the atmosphere through the outlet 25. As the ammonia detoxification treatment progresses in this manner, the pressure inside the pipes of the ammonia supply system 100 decreases, and the blowing of the ammonia-containing gas into the detoxification liquid 22 stops, but the blowing of the ammonia-containing gas into the gas phase section 24 continues until the pressure inside the pipes of the ammonia supply system 100 reaches atmospheric pressure, and when the pressure inside the pipes of the ammonia supply system 100 reaches atmospheric pressure, the flow of the ammonia-containing gas into the storage tank 21 and the release of the detoxified gas into the atmosphere end. Therefore, after the release into the atmosphere is completed, the pressure inside the pipes of the ammonia supply system 100 and the ammonia-containing gas system 4 connected to the ammonia supply system 100 becomes approximately the same as atmospheric pressure, and leakage of the ammonia-containing gas remaining in these pipes to the outside is suppressed.

[0070] The functions performed by the controller 60 described herein may be implemented in circuitry or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), CPUs (Central Processing Units), conventional circuits, and / or combinations thereof, programmed to perform the described functions. Processors include transistors and other circuits and are considered circuitry or processing circuitry. A processor may also be a programmed processor that executes a program stored in memory. In this specification, a circuit, unit, or means is hardware that is programmed to perform or executes the described functions. The hardware may be any hardware disclosed herein or any hardware known to be programmed to perform or execute the described functions. When the hardware is a processor, which is considered a type of circuitry, the circuit, means, or unit is a combination of hardware and software used to configure the hardware and / or processor.

[0071] The foregoing discussion of the present disclosure has been presented for purposes of illustration and description and is not intended to limit the present disclosure to the form disclosed herein. For example, in the foregoing detailed description, various features of the present disclosure are grouped together in a single embodiment for the purpose of streamlining the disclosure, but some of the features may also be combined. Furthermore, the features included in the present disclosure may be combined into alternative embodiments, configurations, or aspects other than those discussed above.

Claims

1. An ammonia abatement apparatus for abating ammonia-containing gas at a pressure higher than atmospheric pressure in an ammonia supply system, comprising: a storage tank for storing an ammonia abatement liquid and having an outlet at a top thereof; a sprinkler nozzle opening into a gas phase portion vertically between the liquid level of the abatement liquid in the storage tank and the outlet; an underwater nozzle opening into the abatement liquid; an air nozzle opening into the gas phase portion; and an ammonia-containing gas system through which the ammonia-containing gas flows from the ammonia supply system to the underwater nozzle and the air nozzle.

2. An ammonia detoxification device as described in claim 1, wherein the underwater nozzles include a first underwater nozzle opening at the bottom of the storage tank, and a second underwater nozzle opening vertically between the first underwater nozzle and the liquid level of the detoxification liquid.

3. The ammonia detoxification device according to claim 2, wherein the total nozzle outlet area of ​​the underwater nozzles and the aerial nozzles that open at the same height in the vertical direction is smaller the higher the nozzle is located in the vertical direction.

4. The ammonia detoxification device according to claim 1, wherein the underwater nozzle is equipped with a fine bubble generator that atomizes the ammonia-containing gas that is sprayed.

5. The ammonia detoxification device according to claim 1, wherein the aerial nozzle is disposed so as to spray the ammonia-containing gas toward the water sprayed from the water sprinkler nozzle.

6. The ammonia detoxification device according to claim 1, wherein the aerial nozzle is configured to mix the ammonia-containing gas with water and eject the mixed gas.

7. The ammonia detoxification apparatus according to claim 1, wherein the ammonia-containing gas system includes a mother pipe connected to the ammonia supply system, a submerged injection pipe connecting the mother pipe and the submerged nozzle, and an air injection pipe connecting the mother pipe and the air nozzle.

8. The ammonia detoxification device according to claim 7, wherein the ammonia-containing gas system includes a first valve for opening and closing the underwater blowing pipe, and a second valve for opening and closing the air blowing pipe.

9. The ammonia detoxification device according to claim 8, further comprising: a pressure sensor for detecting the pressure inside the pipe of the ammonia supply system; and a control device for controlling the opening and closing operations of the first valve and the second valve based on the pressure inside the pipe detected by the pressure sensor, wherein the control device is configured to switch from a state in which the first valve is opened and the second valve is closed, and the ammonia-containing gas is blown out of the underwater nozzle, to a state in which the second valve is opened and the first valve is closed, and the ammonia-containing gas is blown out of the air nozzle, when the pressure inside the pipe falls below a predetermined pressure threshold.

10. The ammonia detoxification device according to claim 9, wherein the pressure threshold value is a value obtained by multiplying the water pressure at the outlet of the underwater nozzle by a variable between 1 and 1.

1.

11. The ammonia detoxification device according to claim 9, further comprising: a sprinkler valve that switches between supplying and stopping water to the sprinkler nozzle; and a release valve that switches between allowing and stopping the inflow of the ammonia-containing gas from the ammonia supply system, wherein the control device is configured to control the opening and closing operations of the release valve and the sprinkler valve so that the sprinkler valve opens and closes in conjunction with the opening and closing of the release valve.

12. A method for ammonia abatement for ammonia-containing gas at a pressure higher than atmospheric pressure in an ammonia supply system, comprising: injecting the ammonia-containing gas into ammonia abatement liquid in a storage tank storing the ammonia abatement liquid through an underwater injection pipe connected to the ammonia supply system; spraying water into a gas phase portion vertically between the liquid level of the abatement liquid in the storage tank and a discharge port at the top of the storage tank; and injecting the ammonia-containing gas into the gas phase portion through an air injection pipe connected to the ammonia supply system so that the gas comes into contact with the water sprayed into the gas phase.

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