Ammonia removal apparatus and method

Abstract

An ammonia removal device for removing an ammonia-containing gas having a higher pressure than atmospheric pressure in an ammonia supply system is provided with: a storage tank for storing an ammonia removal liquid and having a discharge port at the top; a water spraying nozzle which is opened at a gas phase part between the liquid surface of the removing liquid in the storage tank and the vertical direction of the discharge port; an in-water nozzle that opens in the removal liquid; an in-gas nozzle that opens at the gas phase part; and an ammonia-containing gas system that causes an ammonia-containing gas to flow from the ammonia supply system to the underwater nozzle and the in-gas nozzle.

Description

Technical Field

[0001] This disclosure relates to an ammonia removal apparatus and method for removing ammonia components from ammonia-containing gases. Background Technology

[0002] Ammonia removal devices have always been included in facilities that use ammonia, where ammonia-containing gases are separated and the ammonia components are removed before being released into the atmosphere. Patent Document 1 discloses such an ammonia removal device.

[0003] The ammonia removal apparatus disclosed in Patent Document 1 includes: a storage tank storing an aqueous sulfuric acid solution as an ammonia absorbent; an exhaust pipe disposed at the top of the storage tank; and an ammonia-containing gas inlet pipe having an inlet at the bottom of the storage tank. When ammonia-containing gas is blown into the bottom of the storage tank via the ammonia-containing gas inlet pipe, the ammonia in the gas is absorbed and removed by the absorbent. The ammonia-removed gas is released to the atmosphere via the exhaust pipe.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-239130 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In a structure where ammonia-containing gas, supplied via piping to an ammonia removal unit, is deaminated in a removal tank containing ammonia removal liquid before being released to the atmosphere, the pressure inside the piping gradually decreases when the inflow of new ammonia-containing gas into the piping stops, eventually converging to the same pressure as the pressure at the ammonia-containing gas inlet in the removal tank. Since the ammonia-containing gas inlet in the removal tank is located in the removal liquid, its pressure is higher than atmospheric pressure. As a result, even after the atmospheric release from the ammonia removal unit is complete, the pressure inside the piping remains higher than atmospheric pressure. That is, the piping is at a higher pressure than the atmosphere, posing a risk of residual ammonia-containing gas leakage from the piping.

[0009] This disclosure was made in view of the above circumstances, and its object is to provide a technology that, in a structure in which ammonia-containing gas supplied to an ammonia removal device via a piping is released to the atmosphere after the ammonia component is removed in the removal device, suppresses leakage of ammonia-containing gas remaining in the piping after the atmospheric release.

[0010] Methods for solving problems

[0011] To address the aforementioned issues, one aspect of the ammonia removal apparatus disclosed herein is an ammonia removal device for removing ammonia-containing gas at a pressure higher than atmospheric pressure within an ammonia supply system. This ammonia removal apparatus comprises: a storage tank storing ammonia removal liquid and having a discharge port at the top; a water spray nozzle opening in the gas phase between the liquid surface of the removal liquid in the storage tank and the discharge port in a vertical direction; an underwater nozzle opening within the removal liquid; a gas spray nozzle opening in the gas phase; and an ammonia-containing gas system that allows the ammonia-containing gas to flow from the ammonia supply system to the underwater nozzle and the gas spray nozzle.

[0012] To address the aforementioned issues, one aspect of the ammonia removal method disclosed herein is an ammonia removal method for removing ammonia-containing gas at a pressure higher than atmospheric pressure within an ammonia supply system. This ammonia removal method comprises the following steps: blowing the ammonia-containing gas into a storage tank containing ammonia removal liquid via a water inlet pipe connected to the ammonia supply system; spraying water into the gas phase portion between the liquid surface of the removal liquid in the storage tank and the outlet at the top of the storage tank in a vertical direction; and blowing the ammonia-containing gas into the gas phase portion via a gas inlet pipe connected to the ammonia supply system in contact with the water sprayed into the gas phase portion.

[0013] Invention Effects

[0014] According to this disclosure, in a structure in which ammonia-containing gas, supplied to an ammonia removal device via a piping, is released to the atmosphere after the ammonia component is removed in the removal device, leakage of ammonia-containing gas remaining in the piping after the atmospheric release is completed can be suppressed. Attached Figure Description

[0015] Figure 1 This is a schematic structural diagram of an ammonia supply system of an ammonia removal apparatus having one embodiment of the present disclosure.

[0016] Figure 2 This is a schematic structural diagram of an ammonia removal apparatus according to one embodiment of the present disclosure.

[0017] Figure 3 This is a schematic structural diagram of the ammonia removal device of Modified Example 1.

[0018] Figure 4 This is a schematic structural diagram of the ammonia removal device of Modified Example 2.

[0019] Figure 5 This is a timeline diagram of ammonia removal treatment. Detailed Implementation

[0020] Next, embodiments of the present disclosure will be described with reference to the accompanying drawings. Figure 1 This is a schematic structural diagram of an ammonia supply system 100 of an ammonia removal apparatus 2 having one embodiment of the present disclosure.

[0021] Figure 1 The disclosed ammonia supply system 100 is a flow path for supplying ammonia-containing gas to the ammonia burner 5, and is composed of piping and the like. The ammonia burner 5 is one example of an ammonia-using device, but the ammonia-using device is not limited to the ammonia burner 5. In addition, the ammonia-containing gas is any gas that contains ammonia, and the concentration of ammonia in the ammonia-containing gas is not limited.

[0022] The ammonia supply system 100 has a main supply pipe 13 connected to a gas source 12, and a shut-off valve 16 is installed on the main supply pipe 13 to open and close its flow path. One or more supply branch pipes 14 are connected downstream of the main supply pipe 13 from the shut-off valve 16. The supply branch pipes 14 are connected to an ammonia burner 5, and ammonia-containing gas flowing from the main supply pipe 13 to the supply branch pipes 14 is supplied to the ammonia burner 5. A burner valve 17 is installed on the supply branch pipes 14 to open and close its flow path.

[0023] A discharge pipe 15 is connected downstream of the stop valve 16 from the main supply pipe 13. The discharge pipe 15 is used to release ammonia-containing gas remaining in the ammonia supply system 100. A discharge valve 18 is installed on the discharge pipe 15 to open and close the flow path of the discharge pipe 15. An ammonia removal device 2 is connected to the downstream end of the discharge pipe 15.

[0024] In the ammonia supply system 100 with the above-described structure, when ammonia-containing gas is supplied to the ammonia burner 5, the shut-off valve 16 and the burner valve 17 are open, and the discharge valve 18 is closed. Conversely, when the supply of ammonia-containing gas to the ammonia burner 5 is stopped, the shut-off valve 16 and the burner valve 17 are closed, and the discharge valve 18 is open.

[0025] When the ammonia supply system 100 switches from supplying ammonia-containing gas to stopping supply, ammonia-containing gas with a pressure higher than atmospheric pressure remains in the downstream portion of the supply main pipe 13 (below the shut-off valve 16) and the upstream portion of the supply branch pipe 14 (below the burner valve 17). This ammonia-containing gas flows to the ammonia removal device 2 via the release pipe 15 through the opening of the release valve 18. In the ammonia removal device 2, ammonia is removed from the ammonia-containing gas, and the ammonia-removed gas is released to the atmosphere.

[0026] Structure of Ammonia Removal Unit 2

[0027] Here, the structure of ammonia removal device 2 will be described in detail. Figure 2 This is a schematic structural diagram of an ammonia removal device 2 according to one embodiment of the present disclosure.

[0028] Figure 2The ammonia removal device 2 shown includes: a storage tank 21 storing ammonia removal liquid 22; water spray nozzles 31 and 32 spraying water into the gas phase section 24 of the storage tank 21; underwater nozzles 46A and 46B blowing ammonia-containing gas into the removal liquid 22; gas nozzle 47 blowing ammonia-containing gas into the gas phase section 24 of the storage tank 21; and an ammonia-containing gas system 4 that causes ammonia-containing gas to flow from the discharge pipe 15 to the underwater nozzles 46A and 46B and the gas nozzle 47.

[0029] The removal liquid 22 stored in the storage tank 21 is a liquid pre-sealed with ammonia, such as an aqueous solution of sulfuric acid. When ammonia-containing gas is blown into the removal liquid 22, the ammonia in the ammonia-containing gas is absorbed by the removal liquid 22 through the following reaction.

[0030] NH3 + H2O → NH4OH

[0031] 2NH4OH + H2SO4 → (NH4)2SO4 + 2H2O

[0032] A vent 25 is provided at the top of the storage tank 21. Inside the storage tank 21, a gas phase 24 is located between the liquid surface 23 of the removed liquid 22 and the vent 25 in the vertical direction. The gas phase 24 is connected to the outside via the vent 25, and the gas phase 24 is at approximately atmospheric pressure. The gas from which ammonia has been removed from the gas phase 24 is released from the storage tank 21 to the atmosphere via the vent 25.

[0033] The first water spray nozzle 31 is disposed in the gas phase section 24 of the storage tank 21. The first water spray nozzle 31 is preferably disposed in the upper half of the gas phase section 24, and more preferably disposed directly below the outlet 25. The first water spray nozzle 31 is connected to a water supply pipe 30. Water supplied to the first water spray nozzle 31 via the water supply pipe 30 is sprayed from the first water spray nozzle 31 into the gas phase section 24. The first water spray nozzle 31 is preferably a nozzle that sprays water in a manner that diffuses over a wide area. The water sprayed from the first water spray nozzle 31 comes into contact with ammonia gas floating in the gas phase section 24 and absorbs ammonia, becoming ammonia water with dissolved ammonia, which falls into the removal liquid 22.

[0034] exist Figure 2 In the example shown, the water nozzles 46A and 46B comprise a first water nozzle 46A and a second water nozzle 46B with horizontal openings at different heights within the removal liquid 22. At least one first water nozzle 46A is disposed at the bottom of the storage tank 21. At least one second water nozzle 46B is disposed below the liquid surface 23 of the storage tank 21 and above the first water nozzle 46A. However, the ammonia removal device 2 may have at least one water nozzle 46A or 46B opening within the removal liquid 22, or it may have more than three water nozzles.

[0035] The ammonia-containing gas system 4 consists of a main pipe 40 connected to the discharge pipe 15 of the ammonia supply system 100 and inlet pipes 41 and 42 connected to the main pipe 40. Ammonia-containing gas flows from the discharge pipe 15 into the main pipe 40. By opening and closing the discharge valve 18 provided on the discharge pipe 15, the flow of ammonia-containing gas from the discharge pipe 15 into the main pipe 40 can be switched to be stopped. The discharge valve 18 may also be provided on the main pipe 40. Alternatively, the main pipe 40 may also be part of the discharge pipe 15.

[0036] The blow-in pipes 41 and 42 include a water blow-in pipe 41 for blowing ammonia-containing gas into the removal liquid 22 and a gas blow-in pipe 42 for blowing ammonia-containing gas into the gas phase section 24. The water blow-in pipe 41 includes a first water blow-in pipe 41A connected to a first water nozzle 46A and a second water blow-in pipe 41B connected to a second water nozzle 46B. Ammonia-containing gas flows from the main pipe 40 through the first water blow-in pipe 41A to the first water nozzle 46A and is blown out from the first water nozzle 46A into the removal liquid 22. In addition, ammonia-containing gas flows from the discharge pipe 15 through the second water blow-in pipe 41B to the second water nozzle 46B and is blown out from the second water nozzle 46B into the removal liquid 22.

[0037] At least one of the first water nozzle 46A and the second water nozzle 46B may have a microbubble generator. The microbubble generator produces microbubbles with a diameter of less than micrometers. Ammonia-containing microbubbles are blown out from the first water nozzle 46A and the second water nozzle 46B equipped with microbubble generators. The microbubbles are smaller in diameter than millimeter bubbles and float slowly in the removal liquid 22. The contact area between the ammonia-containing microbubbles and the removal liquid 22 is increased, and the contact time is prolonged, thereby promoting the reaction between the ammonia contained in the ammonia-containing gas and the removal liquid 22.

[0038] Since the first water inlet pipe 41A and the second water inlet pipe 41B, as well as the first water nozzle 46A and the second water nozzle 46B, are always submerged in the removal liquid 22, they are preferably made of a material with high corrosion resistance. Stainless steel is an example of such a material.

[0039] At least one gas nozzle 47 is positioned above the liquid level 23 of the storage tank 21 and below the outlet 25. A second water spray nozzle 32, connected to a water supply pipe 30, is positioned near the gas nozzle 47. Water supplied to the second water spray nozzle 32 via the water supply pipe 30 is sprayed from the second water spray nozzle 32 onto the gas phase section 24. The gas nozzle 47 is connected to the main pipe 40 via a gas inlet pipe 42. Ammonia-containing gas flows from the main pipe 40 through the gas inlet pipe 42 to the gas nozzle 47, and is then blown out from the gas nozzle 47 onto the gas phase section 24.

[0040] The air nozzle 47 is configured to mix the ammonia-containing gas blown from it with the water sprayed from the second water nozzle 32. Since the ammonia in the ammonia-containing gas blown from the air nozzle 47 rises in the gas phase 24, it is preferable that the air nozzle 47 opens below the first water nozzle 31 and the second water nozzle 32. However, the second water nozzle 32 can be omitted, and the air nozzle 47 can be configured to mix the ammonia-containing gas blown from it with the water sprayed from the first water nozzle 31. Alternatively, the air nozzle 47 can also be a nozzle with a mixer configured to mix and blow out the ammonia-containing gas supplied from the air inlet pipe 42 with the water supplied from the water supply pipe 30.

[0041] Of the aforementioned nozzles 46A (first water nozzle), 46B (second water nozzle), and 47 (gas nozzle), nozzle 46A (first water nozzle) has the highest ammonia removal efficiency. Therefore, the relationship between at least one of the following—the diameter of the inlet pipe, the outlet area (i.e., the orifice diameter) of the nozzle, and the number of nozzles—is adjusted to preferentially direct ammonia-containing gas towards nozzle 46A (first water nozzle). For example, the diameters of the inlet pipes 41A (first water nozzle), 41B (second water nozzle), and 42 (gas nozzle) are different, decreasing in the order of inlet pipe 41A (first water nozzle), 41B (second water nozzle), and 42 (gas nozzle). Similarly, the combined outlet area of ​​the nozzles 46A (first water nozzle), 46B (second water nozzle), and 47 (gas nozzle) is different, decreasing in the order of inlet pipe 46A (first water nozzle), 46B (second water nozzle), and 47 (gas nozzle). Furthermore, the total outlet area of ​​the first water nozzle 46A refers to the sum of the outlet areas of all first water nozzles 46A connected to the first water inlet pipe 41A. The total outlet area of ​​the second water nozzle 46B and the total outlet area of ​​the air nozzle 47 are the same. For example, the number of first water nozzles 46A, second water nozzles 46B, and air nozzles 47 are different, decreasing in the order of first water nozzles 46A > second water nozzles 46B > air nozzles 47.

[0042] Ammonia Removal Methods

[0043] Here, the ammonia removal method using the aforementioned ammonia removal device 2 will be described. In the ammonia supply system 100, when the shut-off valve 16 and the burner valve 17 (see reference 16) are connected... Figure 1 When the valve 18 is closed and the discharge valve 18 is opened, the ammonia-containing gas remaining in the ammonia supply system 100 at a pressure higher than atmospheric pressure flows into the main pipe 40.

[0044] Most of the ammonia-containing gas flowing into the main pipe 40 is blown into the removal liquid 22 through the first water inlet pipe 41A and the second water inlet pipe 41B, respectively, from the water nozzles 46A and 46B. The ammonia-containing gas blown into the removal liquid 22 from the water nozzles 46A and 46B reacts with the removal liquid 22 and has its ammonia removed as it rises towards the liquid surface 23. The ammonia-removed gas passes through the liquid surface 23 and moves towards the gas phase section 24. Thus, most of the ammonia in the ammonia-containing gas blown into the removal liquid 22 is absorbed by the removal liquid 22. Sometimes, some ammonia remains in the gas moving from the removal liquid 22 to the gas phase section 24. Since ammonia is lighter than air, the ammonia in the gas phase section 24 rises and comes into contact with the water sprayed from the first water spray nozzle 31, dissolving in the water to form ammonia water, which then falls back into the removal liquid 22. The ammonia-removed gas is then released into the atmosphere through the outlet 25.

[0045] The remaining portion of the ammonia-containing gas flowing into the main pipe 40 is blown out from the gas nozzle 47 to the gas phase section 24 via the gas inlet pipe 42. The ammonia-containing gas blown into the gas phase section 24 from the gas nozzle 47 comes into contact with the water sprayed from the second water spray nozzle 32 (or the first water spray nozzle 31), dissolves in the water to become ammonia water, and falls into the removal liquid 22.

[0046] As described above, during the removal of ammonia-containing gas using the ammonia removal device 2, no new ammonia-containing gas flows into the discharge pipe 15, thus the pressure inside the discharge pipe 15 gradually decreases. First, when the pressure inside the discharge pipe 15 drops to the water pressure at the outlet of the first water nozzle 46A, the blowing of ammonia-containing gas from the first water nozzle 46A is stopped. Next, when the pressure inside the discharge pipe 15 drops to the water pressure at the outlet of the second water nozzle 46B, the blowing of ammonia-containing gas from the second water nozzle 46B is stopped. Finally, when the pressure inside the discharge pipe 15 drops to the gas pressure at the outlet of the gas nozzle 47, i.e., atmospheric pressure, the blowing of ammonia-containing gas from the gas nozzle 47 is stopped. Thus, after the blowing of ammonia-containing gas from the first water nozzle 46A and the second water nozzle 46B stops, ammonia-containing gas continues to be blown into the storage tank 21 from the gas nozzle 47 until the pressure inside the discharge pipe 15 becomes atmospheric pressure. In this way, the pressure inside the discharge pipe 15 can automatically drop to atmospheric pressure without relying on the power of the blower or the like. When the pressure inside the discharge pipe 15 reaches atmospheric pressure, the leakage of gas is suppressed from the discharge pipe 15, the connection between the discharge pipe 15 and the main pipe 40, and the connection between the main pipe 40 and each blow-in pipe to the atmosphere.

[0047] [Variation Example]

[0048] Modifications 1 and 2 of the ammonia removal apparatus 2 according to the above embodiment will be described. In Modifications 1 and 2, the flow path of the ammonia-containing gas is operated using a valve, allowing selection of the nozzle from the first water nozzle 46A, the second water nozzle 46B, and the gas nozzle 47 to blow out the ammonia-containing gas. This differs from the ammonia removal apparatus 2 of the above embodiment. Furthermore, in the description of the modifications, components that are the same as or similar to those in the above embodiment are labeled with the same reference numerals in the drawings, and detailed descriptions are omitted.

[0049] Figure 3 This is a schematic structural diagram of the ammonia removal device 2 in Modified Example 1. Figure 3 In the ammonia removal device 2 of the modified example 1 shown, a first valve 51 for opening and closing the flow path of the second water inlet pipe 41B is provided on the second water inlet pipe 41B. A second valve 52 for opening and closing the flow path of the gas inlet pipe 42 is provided on the gas inlet pipe 42. A sprinkler valve 53 is provided on the water supply pipe 30. A pressure sensor 55 for detecting the pressure inside the pipe is provided on the discharge pipe 15.

[0050] Figure 4 This is a schematic structural diagram of the ammonia removal device 2 in Modified Example 2. Figure 4 In the ammonia removal device 2 of Modified Example 2 shown, the control device 60 operates the flow path of ammonia-containing gas using a valve, which is different from the embodiment and Modified Example 1.

[0051] exist Figure 4 In the ammonia removal device 2 shown, a first valve 51 is installed on the second water inlet pipe 41B to open and close the flow path of the second water inlet pipe 41B. A second valve 52 is installed on the gas inlet pipe 42 to open and close the flow path of the gas inlet pipe 42. A spray valve 53 is installed on the water supply pipe 30 to switch the supply and stop of water to the first spray nozzle 31 and the second spray nozzle 32. The first valve 51, the second valve 52, the discharge valve 18, and the spray valve 53 are electrically connected to the control device 60, and these valves open and close according to the instructions of the control device 60. A pressure sensor 55 is installed on the discharge pipe 15 to detect the pressure inside the pipe. The pressure sensor 55 is electrically connected to the control device 60, and the control device 60 operates the flow path of ammonia-containing gas by opening and closing the valves according to the detection value of the pressure sensor 55.

[0052] Ammonia Removal Methods

[0053] Here, refer to Figure 5The timing diagram for ammonia removal illustrates the ammonia removal method using the ammonia removal apparatus 2 of Modified Examples 1 and 2. The ammonia removal method is common to both Modified Examples 1 and 2; however, in Modified Example 1, each valve is opened and closed manually, while in Modified Example 2, the opening and closing of each valve is controlled by the control device 60. Although not explicitly stated, in the ammonia removal method using the ammonia removal apparatus 2 of Modified Example 2, the opening and closing of the first valve 51, the second valve 52, the discharge valve 18, and the sprinkler valve 53 are controlled by the control device 60. The control device 60 is configured to monitor the detection value of the pressure sensor 55 during processing and issue operation commands to each valve based on that detection value.

[0054] In the ammonia supply system 100, when the release of ammonia-containing gas begins based on the activation of a purging command, the shut-off valve 16 and the burner valve 17 (see reference) Figure 1 The discharge valve 18 is opened while the discharge valve 15 is closed. As a result, ammonia-containing gas remaining in the ammonia supply system 100 at a pressure higher than atmospheric pressure flows into the main pipe 40 via the discharge pipe 15. Along with the opening of the discharge valve 18, the sprinkler valve 53 is opened. Water is sprayed starting from the first sprinkler nozzle 31 and the second sprinkler nozzle 32 by opening the sprinkler valve 53.

[0055] Valve 51 and valve 52 are closed beforehand. Therefore, after the initial purging of ammonia gas, the ammonia gas only flows into the first water inlet pipe 41A, and is blown out from the first water nozzle 46A into the removal liquid 22. Here, the blowing of ammonia gas from the second water nozzle 46B and the gas nozzle 47 is stopped.

[0056] When ammonia removal is performed in the ammonia removal device 2, and the pressure inside the discharge pipe 15 detected by the pressure sensor 55 falls below the first pressure threshold P1, the first valve 51 is opened. The height from the first water nozzle 46A to the liquid surface 23 is defined as Hd, the height from the second water nozzle 46B to the liquid surface 23 is defined as Hs, the density of the removed liquid 22 is defined as ρ, and the acceleration due to gravity is defined as g. ρ, g, Hd, and Hs are known or controlled values, provided in advance to the control device 60. The water pressure at the outlet of the first water nozzle 46A is represented by ρgHd, and the water pressure at the outlet of the second water nozzle 46B is represented by ρgHs. The aforementioned first pressure threshold P1 is ρgHd × n1. Here, n1 is a variable greater than 1 and less than 1.1. That is, the first pressure threshold P1 is a pressure equal to or slightly higher than the water pressure at the outlet of the first water nozzle 46A. The control device 60 can use a given value of n1 to calculate the first pressure threshold P1. The value of n1 can be a value pre-stored in a memory connected to the control device 60, a value input in a timely manner via an input device connected to the control device 60, or a value sent remotely to the control device 60 via a communication line.

[0057] When the first valve 51 is opened, ammonia-containing gas is blown into the removal liquid 22 through the second water inlet pipe 41B and the second water nozzle 46B. As the pressure inside the discharge pipe 15 of the ammonia supply system 100 further decreases, the blowing of ammonia-containing gas from the first water nozzle 46A automatically stops. However, to prevent backflow of the removal liquid 22 into the first water inlet pipe 41A, an additional on / off valve can be installed on the first water inlet pipe 41A. Closing this on / off valve will forcibly stop the blowing of ammonia-containing gas from the first water nozzle 46A.

[0058] When further ammonia removal treatment is performed in the ammonia removal device 2, and the pressure inside the outlet 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 aforementioned second pressure threshold P2 is represented by ρgMs×n2. Here, n2 is a variable greater than 1 and less than 1.1. That is, the second pressure threshold P2 is the same as or slightly higher than the water pressure at the outlet of the second water nozzle 46B. The control device 60 can calculate the second pressure threshold P2 using a given value of n2. The value of n2 can be a value pre-stored in a memory connected to the control device 60, a value input in real time via an input device connected to the control device 60, or a value remotely transmitted to the control device 60 via a communication line.

[0059] When the second valve 52 is opened, ammonia-containing gas is blown from the gas nozzle 47 into the gas phase section 24 via the gas inlet pipe 42. To prevent the removal liquid 22 from flowing back into the second water inlet pipe 41B, the first valve 51 is closed, forcibly stopping the blowing of ammonia-containing gas from the second water nozzle 46B.

[0060] When the pressure inside the discharge pipe 15 drops to the outlet pressure of the gas nozzle 47, i.e., atmospheric pressure, the blowing of ammonia-containing gas from the gas nozzle 47 automatically stops. After the pressure inside the discharge pipe 15 drops to atmospheric pressure, the discharge valve 18 and the second valve 52 are closed, and then the water spray valve 53 is closed to end the discharge process.

[0061] As described above, in the ammonia removal apparatus 2 of Modified Examples 1 and 2, the flow path of the ammonia-containing gas is operated by a valve, thereby switching the nozzles that blow out the ammonia-containing gas in the order of the first water nozzle 46A, the second water nozzle 46B, and the gas nozzle 47 as the pressure inside the discharge pipe 15 decreases. This increases the proportion of ammonia-containing gas blown out from the first water nozzle 46A in the treated ammonia-containing gas to a possible extent, enabling efficient ammonia removal.

[0062] 〔Summarize〕

[0063] The ammonia removal apparatus 2 of the first item of this disclosure removes ammonia-containing gas with a pressure higher than atmospheric pressure within an ammonia supply system 100. The ammonia removal apparatus 2 includes: a storage tank 21 storing ammonia removal liquid 22 and having a discharge port 25 at the top; water spray nozzles 31 and 32 opening in the gas phase portion 24 between the liquid surface 23 of the removal liquid 22 in the storage tank 21 and the discharge port 25 in the vertical direction; underwater nozzles 46A and 46B opening in the removal liquid 22; gas nozzle 47 opening in the gas phase portion 24; and an ammonia-containing gas system 4 supplying ammonia-containing gas from the ammonia supply system 100 to the underwater nozzles 46A and 46B and the gas nozzle 47.

[0064] According to the ammonia removal device 2 with the above-described structure, the ammonia-containing gas from the ammonia supply system 100 is blown out from both the water nozzles 46A and 46B and the gas nozzle 47. During the ascent of the ammonia-containing gas blown from the water nozzles 46A and 46B into the removal liquid 22, the ammonia contained within is absorbed and separated by the removal liquid 22. The ammonia-removed gas is discharged into the gas phase section 24 and then released to the atmosphere through the outlet 25. The ammonia-containing gas blown from the gas nozzle 47 into the gas phase section 24 mixes with the water sprayed from the water spray nozzles 31 and 32. The ammonia dissolves in the water to form ammonia water, which falls back into the removal liquid 22. The ammonia-removed gas is then released to the atmosphere through the outlet 25. After the ammonia removal process is performed and the pressure inside the ammonia supply system 100 (in this embodiment, the discharge pipe 15) is lower than the outlet pressure of the water nozzles 46A and 46B, the blowing of ammonia-containing gas from the water nozzles 46A and 46B stops. However, the blowing from the gas nozzle 47 continues until the pressure inside the ammonia supply system 100 reaches atmospheric pressure. When the pressure inside the ammonia supply system 100 reaches atmospheric pressure, the inflow of ammonia-containing gas into the storage tank 21 and the atmospheric release of the removed gas end. Therefore, after the atmospheric release, the pressure inside 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 ammonia-containing gas remaining in these pipes to the outside is suppressed.

[0065] The ammonia removal apparatus 2 of the second item of this disclosure is based on the ammonia removal apparatus 2 of the first item, wherein the water nozzles 46A and 46B comprise: a first water nozzle 46A which opens at the bottom of the storage tank 21; and a second water nozzle 46B which opens in the vertical direction between the first water nozzle 46A and the liquid surface 23 of the removal liquid 22.

[0066] In the ammonia removal device 2 with the above-described structure, after the ammonia-containing gas stops being blown out from the first water nozzle 46A, ammonia-containing gas continues to be blown out from the second water nozzle 46B. Therefore, compared to the case with only the first water nozzle 46A, more ammonia-containing gas can be blown into the removal liquid 22, thereby improving the efficiency of ammonia removal treatment.

[0067] According to the ammonia removal apparatus 2 of the third item of this disclosure, in the water nozzles 46A, 46B and the gas nozzle 47, the nozzles that are arranged higher in the vertical direction have a smaller total nozzle outlet area of ​​nozzles that open at the same height in the vertical direction.

[0068] According to the ammonia removal device 2 with the above structure, the nozzle that is positioned lower in the vertical direction is more likely to blow out ammonia-containing gas, and ammonia-containing gas is preferentially blown out from the nozzle that is positioned lower in the vertical direction.

[0069] The ammonia removal apparatus 2 of the fourth item of this disclosure is based on the ammonia removal apparatus 2 of any of the first to third items, wherein the water nozzles 46A and 46B have microbubble generators that refine the blown ammonia-containing gas.

[0070] In the ammonia removal device 2 with the above structure, the bubbles of ammonia-containing gas blown from the water nozzles 46A and 46B into the removal liquid 22 are miniaturized. By increasing the contact area between the ammonia-containing gas and the removal liquid 22 and increasing the residence time of the ammonia-containing gas in the removal liquid 22, the efficiency of ammonia removal treatment can be improved.

[0071] The ammonia removal apparatus 2 of the fifth item of this disclosure is based on the ammonia removal apparatus 2 of any of the first to fourth items, wherein the gas nozzle 47 is configured to blow ammonia-containing gas toward water sprayed from the water spray nozzles 31, 32.

[0072] In the ammonia removal device 2 with the above-described structure, the ammonia-containing gas blown into the gas phase section 24 immediately mixes with the water blown from the water spray nozzles 31 and 32, and the ammonia in the ammonia-containing gas dissolves in the water and is separated from the ammonia-containing gas. Therefore, the efficiency of ammonia removal treatment can be improved.

[0073] The ammonia removal apparatus 2 of the sixth item of this disclosure is based on the ammonia removal apparatus 2 of any of the first to fourth items, wherein the gas nozzle 47 is configured to mix and blow out ammonia-containing gas with water.

[0074] In the ammonia removal device 2 with the above-described structure, the ammonia-containing gas is blown into the gas phase section 24 in a state of being mixed with water such as spray water. Therefore, the ammonia in the ammonia-containing gas immediately dissolves in the water and is separated from the ammonia-containing gas. Thus, the efficiency of ammonia removal treatment can be improved.

[0075] The ammonia removal apparatus 2 of the seventh item of this disclosure, according to any one of the ammonia removal apparatus 2 of items 1 to 6, wherein the ammonia-containing gas system 4 includes: a main pipe 40 connected to the ammonia supply system 100; water blow-in pipes 41A and 41B connecting the main pipe 40 and water nozzles 46A and 46B; and gas blow-in pipe 42 connecting the main pipe 40 and gas nozzles 47.

[0076] The ammonia removal apparatus 2 of the eighth item of this disclosure is based on the ammonia removal apparatus 2 of the seventh item, wherein the ammonia-containing gas system 4 includes: a first valve 51, which opens and closes the water inlet pipe 41B; and a second valve 52, which opens and closes the gas inlet pipe 42.

[0077] In the ammonia removal device 2 with the above-described structure, the nozzle from which ammonia-containing gas is blown out can be selected by opening and closing the first valve 51 and the second valve 52. Therefore, more ammonia-containing gas is blown into the removal liquid 22, thereby improving the efficiency of ammonia removal treatment.

[0078] The ammonia removal apparatus 2 of the 9th item of this disclosure is based on the ammonia removal apparatus 2 of the 7th or 8th item, wherein the ammonia removal apparatus 2 further comprises: 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 of the first valve 51 and the second valve 52 according to the pressure inside the pipe detected by the pressure sensor 55. The control device 60 is configured to switch from a state in which the first valve 51 is open and the second valve 52 is closed and ammonia-containing gas is blown out from the water nozzle 46B when the pressure inside the pipe becomes below a predetermined pressure threshold P2, to a state in which the second valve 52 is open and the first valve 51 is closed and ammonia-containing gas is blown out from the gas nozzle 47.

[0079] According to the ammonia removal device 2 with the above structure, the flow path of ammonia-containing gas is automatically operated by opening and closing the first valve 51 and the second valve 52 based on the control device 60, so that more ammonia-containing gas is blown into the removal liquid 22, and ammonia-containing gas is continuously released until the pressure inside the ammonia supply system 100 becomes atmospheric pressure.

[0080] The ammonia removal apparatus 2 of the 10th item of this disclosure is based on the ammonia removal apparatus 2 of the 9th item, wherein the pressure threshold P2 is a value obtained by multiplying the water pressure at the outlet of the nozzle 46B in the water by a variable of more than 1 and less than 1.1.

[0081] According to the ammonia removal device 2 with the above structure, by adjusting the variable, the timing of switching the nozzle that blows out ammonia-containing gas from the water nozzle 46B to the gas nozzle 47 can be adjusted.

[0082] According to the ammonia removal device 2 of the 11th item of this disclosure, which is based on the ammonia removal device 2 of the 9th or 10th item, the ammonia removal device 2 further includes: a water spray valve 53, which switches between supplying water to and stopping the water supply to water spray nozzles 31, 32; and a discharge valve 18, which switches between allowing the flow of ammonia-containing gas from the ammonia supply system 100 and stopping the flow of ammonia-containing gas. The control device 60 is configured to control the opening and closing of the discharge valve 18 and the water spray valve 53, so that the water spray valve 53 and the discharge valve 18 open and close in conjunction.

[0083] According to the above-described ammonia removal device 2, it can automatically start spraying water into the storage tank 21 in response to the inflow of ammonia-containing gas into the storage tank 21.

[0084] The ammonia removal method of the 12th item of this disclosure is a method for removing ammonia-containing gas with a pressure higher than atmospheric pressure within an ammonia supply system 100. The ammonia removal method includes the following steps: blowing the ammonia-containing gas into the removal liquid 22 of a storage tank 21 containing the ammonia removal liquid 22 via water blow-in pipes 41A and 41B connected to the ammonia supply system 100; spraying water into the gas phase section 24 between the liquid surface 23 of the removal liquid 22 in the storage tank 21 and the outlet 25 at the top of the storage tank 21 in the vertical direction; and blowing the ammonia-containing gas into the gas phase section 24 via a gas blow-in pipe 42 connected to the ammonia supply system 100 in such a way that it comes into contact with the water sprayed into the gas phase section 24.

[0085] According to the ammonia removal method described above, ammonia-containing gas from the ammonia supply system 100 is blown into both the removal liquid 22 and the gas phase section 24. During the ascent of the ammonia-containing gas into the removal liquid 22, the ammonia contained within is absorbed and separated by the removal liquid 22. The ammonia-removed gas is then discharged into the gas phase section 24 and released to the atmosphere via the outlet 25. The ammonia-containing gas blown into the gas phase section 24 mixes with sprayed water, causing the ammonia in the gas to dissolve and separate in the water. The ammonia-removed gas is then released to the atmosphere via the outlet 25. If ammonia removal is performed in this manner, the pressure inside the ammonia supply system 100 decreases, and the blowing of ammonia-containing gas into the removal liquid 22 stops. However, the blowing of ammonia-containing gas into the gas phase section 24 continues until the pressure inside the ammonia supply system 100 reaches atmospheric pressure. When the pressure inside the ammonia supply system 100 reaches atmospheric pressure, the inflow of ammonia-containing gas into the storage tank 21 and the release of the removed gas to the atmosphere cease. Therefore, after the atmospheric release is completed, the pressure inside the ammonia supply system 100 and the ammonia-containing gas system 4 connected to the ammonia supply system 100 is approximately the same as the atmospheric pressure, and the leakage of the ammonia-containing gas remaining in these pipes to the outside is suppressed.

[0086] The functions implemented by the control device 60 described in this specification can also be installed in a circuit or processing circuit programmed to implement the described functions, including a general-purpose processor, a special-purpose processor, an integrated circuit, ASICs (Application Specific Integrated Circuits), a CPU (Central Processing Unit), conventional circuits, and / or combinations thereof. A processor contains transistors or other circuitry and is considered a circuit or processing circuitry. A processor can also be a programmed processor that executes a program stored in memory. In this specification, a circuit, unit, or component is hardware programmed to implement or execute the described functions. This hardware can be all hardware disclosed in this specification, or all hardware known to be programmed or executed to implement the described functions. In the case where the hardware is a processor of the type considered a circuit, the circuit, component, or unit is a combination of hardware and software used to constitute the hardware and / or processor.

[0087] The foregoing discussion of this disclosure is for illustrative purposes and is not intended to limit this disclosure to the manner disclosed in this specification. For example, in the foregoing detailed description, various features of this disclosure are summarized into one embodiment for the purpose of rationalizing this disclosure, but several of the multiple features may also be combined. In addition, the multiple features included in this disclosure may also be combined with alternative embodiments, structures, or methods other than those discussed above.

Claims

1. An ammonia removal device for removing ammonia-containing gas from an ammonia supply system at a pressure higher than atmospheric pressure, wherein, The ammonia removal device has the following features: A storage tank for storing ammonia removal liquid, with a discharge outlet at the top; A water spray nozzle having an opening in the gas phase between the liquid level of the removal liquid in the storage tank and the outlet in the vertical direction; A nozzle in water, which opens into the removal liquid; A nozzle in the gas phase, which opens in the gas phase section; as well as An ammonia-containing gas system that allows the ammonia-containing gas to flow from the ammonia supply system to the water nozzle and the gas nozzle.

2. The ammonia removal device according to claim 1, wherein, The underwater nozzle comprises: A first water nozzle, which opens at the bottom of the storage tank; and The second water nozzle has an opening between the first water nozzle and the surface of the removed liquid in the vertical direction.

3. The ammonia removal device according to claim 2, wherein, Among the underwater nozzles and the air nozzles, the nozzles positioned higher in the vertical direction have smaller combined nozzle outlet areas for nozzles opening at the same height in the vertical direction.

4. The ammonia removal device according to claim 1, wherein, The underwater nozzle has a microbubble generator that refines the ammonia-containing gas being blown out.

5. The ammonia removal device according to claim 1, wherein, The gas nozzle is configured to blow the ammonia-containing gas toward the water sprayed from the sprinkler nozzle.

6. The ammonia removal device according to claim 1, wherein, The gas nozzle is configured to mix the ammonia-containing gas with water and blow it out.

7. The ammonia removal device according to claim 1, wherein, The ammonia-containing gas system includes: The main pipe is connected to the ammonia supply system; A water inlet pipe connects the main pipe and the water nozzle; and An air-blowing tube connects the main tube and the air-blowing nozzle.

8. The ammonia removal device according to claim 7, wherein, The ammonia-containing gas system includes: The first valve opens and closes the water inlet pipe; and The second valve opens and closes the gas-blowing pipe.

9. The ammonia removal device according to claim 8, wherein, The ammonia removal device also features: A pressure sensor that detects the pressure inside the pipes of the ammonia supply system; as well as The control device controls the opening and closing of the first valve and the second valve based on the pressure inside the pipe detected by the pressure sensor. The control device is configured to switch from a state where the first valve is open and the second valve is closed, and the ammonia-containing gas is blown out from the nozzle in the water, to a state where the second valve is open and the first valve is closed, and the ammonia-containing gas is blown out from the nozzle in the gas when the pressure inside the pipe is below a predetermined pressure threshold.

10. The ammonia removal device according to claim 9, wherein, The pressure threshold is a value obtained by multiplying the water pressure at the outlet of the nozzle in the water by a variable greater than 1 and less than 1.

1.

11. The ammonia removal device according to claim 9, wherein, The ammonia removal device also features: A sprinkler valve that switches between supplying water to and stopping the water supply to the sprinkler nozzles; and A discharge valve that switches between allowing the flow of ammonia-containing gas from the ammonia supply system and stopping the flow of ammonia-containing gas. The control device is configured to control the opening and closing actions of the discharge valve and the sprinkler valve, so that the opening and closing of the sprinkler valve and the discharge valve are linked.

12. An ammonia removal method for removing ammonia-containing gas from an ammonia supply system at a pressure higher than atmospheric pressure, wherein... The ammonia removal method includes the following steps: The ammonia-containing gas is blown into the removal liquid in the storage tank containing the ammonia removal liquid via a water blow-in pipe connected to the ammonia supply system. Spray water onto the vapor phase between the liquid level of the removal liquid in the storage tank and the outlet at the top of the storage tank in a vertical direction; as well as The ammonia-containing gas is blown in through a gas-blowing pipe connected to the ammonia supply system in such a way that it comes into contact with water sprayed onto the gas phase.

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