Waste ammonia gas absorption device, ammonia water storage system and waste ammonia gas absorption method

Abstract

The invention discloses a waste ammonia gas absorption device, an ammonia water storage system and a waste ammonia gas absorption method. The waste ammonia gas absorption device comprises an ammonia gas absorption tank, and the ammonia gas absorption tank comprises a tank body, an inner cylinder, a first partition plate and a second partition plate. The first partition plate is fixedly connected between the inner side wall of the tank body and the outer wall of the inner cylinder, and an upper-layer liquid storage space is formed on the upper portion of the first partition plate. The second partition plate is vertically fixed to the surface of the bottom in the tank body, and a lower-layer liquid storage space is formed on the side, facing the inner barrel, of the second partition plate. The ammonia water storage system comprises an ammonia water storage tank and the ammonia gas absorption device; a waste ammonia gas outlet in the ammonia gas storage tank is connected with an ammonia gas inlet of the ammonia gas absorption tank through a pipeline, a waste ammonia gas inlet is connected with an overflow port of the ammonia gas absorption tank through a pipeline, and a sewage inlet is connected with a water outlet and an emptying port of the ammonia gas absorption tank through pipelines. The waste ammonia gas volatilized from the ammonia water storage tank can be well absorbed, and the ammonia smell of an ammonia area is eliminated.

Description

Technical Field

[0001] The present invention relates to an ammonia water storage system in a flue gas denitration process commonly used in industries such as petrochemicals, coal chemicals and fine chemicals, and in particular to a waste ammonia absorption device, an ammonia water storage system and a waste ammonia absorption method. Background Art

[0002] Commonly used reducing agents in flue gas denitrification processes include ammonia water, liquid ammonia, and urea. Because liquid ammonia is a hazardous chemical, and with the country's increasing emphasis on safety, a series of related restrictive measures have been gradually introduced. As a result, the use of liquid ammonia in many new plants is increasingly restricted in terms of approvals, construction periods, land occupation, and other aspects. The main processes for producing ammonia gas using urea as a reducing agent include urea pyrolysis and urea hydrolysis. However, due to the high initial investment cost, high subsequent operating expenses, and serious crystallization and blockage problems in equipment and pipelines during operation, some owners are quite cautious when using urea as a reducing agent. Compared to liquid ammonia, ammonia water has a lower safety risk factor, and the process of preparing ammonia gas from ammonia water is simpler, making it the preferred denitrification reducing agent for some chemical plants.

[0003] During the loading, unloading, and use of ammonia, some ammonia volatilizes. If not promptly absorbed, the leaked ammonia will form ammonia mist. While heavier than air, its molecular weight is smaller, but it reacts with water in the air to form ammonia droplets, creating a cloud. Therefore, when ammonia leaks, it does not naturally diffuse into the air but instead accumulates on the ground, posing a risk to on-site workers. Furthermore, the explosion limit of ammonia is 16% to 25%. If ammonia leaks accumulate in a localized area, it can mix with air to form an explosive mixture, potentially causing combustion and explosion when exposed to open flames or high temperatures.

[0004] Currently, a common method for absorbing volatilized ammonia in ammonia storage areas is to connect the overflow pipe from the ammonia storage tank to a wastewater pool. The volatilized ammonia flows through the overflow pipe into the wastewater pool, where it is absorbed by the water. This method requires the installation of a wastewater pool and a supporting wastewater pump, which occupies a large area and increases investment costs. Furthermore, the wastewater pool is generally not tightly sealed, and an ammonia odor still exists in the ammonia area. Furthermore, the waste ammonia in the wastewater pool is typically pumped to the plant's sewage treatment system, resulting in waste ammonia. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a waste ammonia absorption device, an ammonia water storage system and a waste ammonia absorption method, so as to at least achieve the purpose of improving the absorption effect of volatile ammonia in the ammonia zone.

[0006] To solve the above technical problems, according to one aspect of the present invention, a waste ammonia absorption device is provided, comprising an ammonia absorption tank, wherein the ammonia absorption tank comprises a tank body, an inner cylinder, a first partition plate and a second partition plate; The inner cylinder is a hollow structure, longitudinally arranged in the middle of the tank body, with gaps left between the top of the inner cylinder and the top of the tank body, and between the bottom of the inner cylinder and the bottom of the tank body; the first partition is an annular structure, fixedly connected between the inner wall of the tank body and the outer wall of the inner cylinder, forming an upper liquid storage space on the upper part of the first partition; The second partition is vertically fixed to the bottom surface of the tank body, the top of the second partition is higher than the bottom end of the inner tube and is located outside the inner tube, forming a lower liquid storage space on the side of the second partition facing the inner tube, and forming an overflow space on the side of the second partition facing away from the inner tube; A water inlet and an ammonia inlet are provided on the top of the tank body, a drain outlet is provided on the side wall of the tank body corresponding to the bottom of the upper liquid storage space, an emptying outlet is provided on the side wall of the tank body corresponding to the bottom of the lower liquid storage space, and an overflow outlet is provided on the side wall of the tank body corresponding to the bottom of the overflow space.

[0007] Furthermore, an air inlet is provided on the top of the tank body, and a gas outlet is provided on the side wall of the tank body below the first partition, and the distance between the gas outlet and the bottom of the tank body is higher than the height of the second partition.

[0008] Furthermore, the height difference between the top end of the second partition and the bottom end of the inner tube is 50 mm.

[0009] According to another aspect of the present invention, there is provided an ammonia water storage system, comprising an ammonia water storage tank and the ammonia gas absorption device described above; The ammonia water storage tank is provided with an ammonia water inlet, a waste ammonia outlet, a sewage inlet, and a waste ammonia water inlet; wherein the waste ammonia outlet is connected to the ammonia inlet of the ammonia absorption tank through a pipeline, the waste ammonia water inlet is connected to the overflow port of the ammonia absorption tank through a pipeline, and the sewage inlet is connected to the drain outlet and emptying port of the ammonia absorption tank through a pipeline.

[0010] Furthermore, a U-shaped bend is provided on the connecting pipe between the waste ammonia water inlet and the overflow port.

[0011] Furthermore, a glass sight glass is provided on the connecting pipe at the rear of the U-bend.

[0012] According to another aspect of the present invention, a method for absorbing waste ammonia is provided, based on the above-mentioned ammonia water storage system, comprising the following steps: Install a water inlet pipe at the water inlet of the ammonia absorption tank, and install an air inlet pipe at the air inlet; inject water into the ammonia absorption tank through the water inlet pipe, so that the water is injected into the upper liquid storage space and the lower liquid storage space; Ammonia water is injected into the ammonia water storage tank, and the volatilized waste ammonia gas enters the ammonia absorption tank through the connecting pipe between the waste ammonia gas outlet and the ammonia gas inlet of the ammonia absorption tank. The waste ammonia gas is absorbed by the upper liquid and the lower liquid in the ammonia absorption tank. After the liquid absorbs the waste ammonia gas, it becomes waste ammonia liquid. After the amount of waste ammonia liquid reaches the preset value, it enters the ammonia water storage tank through the connecting pipe between the overflow port and the waste ammonia water inlet.

[0013] Furthermore, when the ammonia water storage tank is filled with ammonia water, outside air enters the ammonia absorption tank through the air inlet pipe, and passes through the connecting pipe between the ammonia inlet and the waste ammonia outlet into the ammonia water storage tank, thereby breaking the vacuum condition of the ammonia absorption tank and the ammonia water storage tank, and maintaining the two storage tanks at normal pressure at all times.

[0014] Furthermore, after the ammonia absorption tank has been used for a period of time, the drain port and the emptying port are opened to drain the waste liquid in the ammonia absorption tank into the ammonia water storage tank, and then water is injected into the ammonia water absorption tank to achieve replacement of the liquid in the ammonia absorption tank.

[0015] Furthermore, two small holes are opened on the side wall of the water inlet pipe.

[0016] The waste ammonia absorption device, ammonia water storage system and waste ammonia absorption method provided by the present invention can not only effectively absorb the waste ammonia gas volatilized from the ammonia water storage tank, eliminate the ammonia odor in the ammonia area, and provide a healthy working environment for on-site operating personnel; but also can promptly break the vacuum state in the ammonia water storage tank to ensure that the equipment is in a stable and safe operating state.

[0017] In addition, the technical solution provided by the present invention can reduce the floor space occupied by the ammonia water storage area and reduce the project investment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings herein are used to provide further illustration of the present invention and constitute a part of this application. The illustrative embodiments of the present invention and their description are used to explain the present invention and do not constitute improper limitations on the present invention.

[0019] Figure 1 This is a schematic structural diagram of the ammonia absorption tank provided by the present invention; Figure 2 It is a structural schematic diagram of the ammonia storage system provided by the present invention.

[0020] In the figure, 1- ammonia absorption tank, 2- ammonia storage tank, 3- tank body, 4- inner cylinder, 5- first baffle, 6- second baffle, 7- upper liquid storage space, 8- lower liquid storage space, 9- overflow space, 10- U-shaped bend, 11- glass sight glass, 12- water inlet pipe, 13- air inlet pipe, 14- upper liquid, 15- lower liquid; N1-water inlet, N2-ammonia inlet, N3-air inlet, N4-gas outlet, N5-overflow, N6-drain outlet, N7-emptying outlet, N8-ammonia inlet, N9-waste ammonia outlet, N10-wastewater inlet, N11-waste ammonia inlet. DETAILED DESCRIPTION

[0021] In order to make those skilled in the art better understand the present invention, the present invention is further clearly and completely described below in conjunction with the accompanying drawings and embodiments. It should be noted that, unless there is a conflict, the features in the embodiments and examples of this application can be combined with each other.

[0022] like Figure 1 As shown, a typical embodiment of the present invention provides a waste ammonia absorption device, which includes an ammonia absorption tank 1. The ammonia absorption tank 1 includes a tank body 3, an inner tube 4, a first partition 5 and a second partition 6.

[0023] The inner tube 4 is a hollow structure and is longitudinally arranged in the middle of the tank body 3. There are gaps between the top of the inner tube 4 and the top of the tank body 3, and between the bottom of the inner tube 4 and the bottom of the tank body 3; the first partition 5 is an annular structure and is fixedly connected between the inner wall of the tank body 1 and the outer wall of the inner tube 4, forming an upper liquid storage space 7 on the upper part of the first partition 5.

[0024] The second partition 6 is vertically fixed to the inner bottom surface of the tank body 3 , and the top end of the second partition 6 is higher than the bottom end of the inner tube 4 and is located outside the inner tube 4 .

[0025] A lower liquid storage space 8 is formed on the side of the second partition 6 facing the inner cylinder 4 , and an overflow space 9 is formed on the side of the second partition 6 facing away from the inner cylinder 4 .

[0026] A water inlet N1 and an ammonia inlet N2 are provided on the top of the tank body 3, a drain outlet N6 is provided on the side wall of the tank body 3 corresponding to the bottom of the upper liquid storage space 7, an emptying outlet N7 is provided on the side wall of the tank body 3 corresponding to the bottom of the lower liquid storage space 8, and an overflow outlet N5 is provided on the side wall of the tank body 3 corresponding to the bottom of the overflow space 9.

[0027] The water inlet pipe 12 is installed at the water inlet N1 and extends below the liquid level of the upper liquid 14. There are two small holes on the side wall of the water inlet pipe 12, which are used to break the vacuum and prevent the siphon phenomenon in the later operation of the pipe, which will cause the waste ammonia to be sucked back into the water injection pipe.

[0028] In this embodiment, two partitions and an inner cylinder 4 divide the ammonia absorption tank into a gas phase and a liquid phase. The waste ammonia absorption device is used in conjunction with an ammonia water storage tank 2. Fresh process water or demineralized water is added to the ammonia absorption tank 1 to absorb the waste ammonia volatilized from the ammonia water storage tank.

[0029] Because ammonia is highly soluble in water, the volatilized waste ammonia gas within the ammonia storage tank 2 is absorbed by the upper and lower liquid layers 14, 15 of the ammonia absorption tank 1, and becomes waste ammonia water. During this process, the ammonia gas is first absorbed by the upper liquid layer 14. The waste ammonia water then overflows from the inner tube 4 into the lower liquid layer 15. It then overflows through the second baffle 6 to the overflow port N5, overcomes the U-shaped curve on the outlet pipe of the overflow port N5, and enters the ammonia storage tank. It is then pumped to the denitration reaction zone by the ammonia pump, avoiding waste of the waste ammonia water.

[0030] In a preferred embodiment, an air inlet N3 is further provided at the top of the tank body 3, and a gas outlet N4 is provided on the side wall of the tank body 3 below the first baffle 5. The distance between the gas outlet N4 and the bottom of the tank body 3 is higher than the height of the second baffle 6. The connecting pipes of the air inlet N3 and the gas outlet N4 are connected to the atmosphere after merging.

[0031] The air inlet pipe 13 extends into the ammonia absorption tank 1 by a certain distance H1 through the air inlet N3, ensuring that the air inlet pipe 13 extends below the liquid level to achieve a liquid seal for the waste ammonia.

[0032] A certain height difference H2 exists between the top of the second baffle 6 and the bottom of the inner tube 4, forming a water seal to prevent waste ammonia from passing through the inner tube 4 and escaping into the atmosphere through the gas outlet N4. For example, the height difference between the top of the second baffle 6 and the bottom of the inner tube 4 is 50 mm. H2 should be greater than H1. For example, the insertion depth H1 is 20 mm. This ensures that when negative pressure occurs in the ammonia storage tank, the outside air can quickly enter the tank through the air inlet N3, achieving the vacuum-breaking function.

[0033] According to this embodiment, as the liquid level of the ammonia water storage tank 2 decreases with the increase of usage time, negative pressure will appear in the ammonia absorption tank 1 and the ammonia water storage tank 2. At this time, the air outside the tank overcomes the negative pressure inside the tank and enters the ammonia absorption tank 1 and the ammonia water storage tank 2 through the air inlet N3 of the ammonia absorption tank 1, thereby ensuring that the two tanks are always in a normal pressure state.

[0034] Another typical embodiment of the present invention provides an ammonia storage system, referring to Figure 2 , which includes an ammonia water storage tank 2 and the ammonia absorption device 1 disclosed in the above embodiments.

[0035] The ammonia water storage tank 2 is provided with an ammonia water inlet N8, a waste ammonia gas outlet N9, a sewage inlet N10, and a waste ammonia water inlet N11.

[0036] Among them, the waste ammonia outlet N9 is connected to the ammonia inlet N2 of the ammonia absorption tank 1 through a pipeline, the waste ammonia water inlet N11 is connected to the overflow port N5 of the ammonia absorption tank 1 through a pipeline, and the sewage inlet N10 is connected to the drain port N6 and the emptying port N7 of the ammonia absorption tank 1 through a pipeline.

[0037] A manual valve is installed on each of the pipes connecting the drain outlet N6 and the emptying outlet N7 of the ammonia absorption tank 1. After the pipes are combined, they are connected to the sewage connection N10 of the ammonia storage tank. If the water in the ammonia absorption tank 1 needs to be replaced or the tank needs maintenance, the manual valve is opened to drain the waste liquid that has absorbed ammonia from the ammonia absorption tank 1 into the ammonia storage tank 2 below.

[0038] For example, in this embodiment, the ammonia water storage tank 2 measures 3000 mm in diameter by 4500 mm in height and is made of 304 stainless steel. The ammonia gas absorption tank 1 measures 820 mm in diameter by 1000 mm in height. It is internally provided with a first baffle 5, a second baffle 6, and an inner tube 4 measuring 325 mm in diameter by 600 mm in height. The tank body and the aforementioned internal components of the ammonia gas absorption tank 1 are also made of 304 stainless steel.

[0039] In a preferred embodiment, a U-bend 10 is provided on the connecting pipe between the waste ammonia inlet N11 and the overflow port N5 to provide a water seal, preventing waste ammonia gas from the ammonia storage tank 2 from entering the ammonia absorption tank 1 through the waste ammonia inlet N11 and then escaping into the atmosphere through the gas outlet N4. For example, the U-bend height H3 can be within a range of 100 to 200 mm.

[0040] In a preferred embodiment, a glass sight glass 11 is provided on the connecting pipe at the rear of the U-shaped bend 10 for observing whether the ammonia absorption tank 1 is filled with water during the initial water injection.

[0041] Another typical embodiment of the present invention provides a waste ammonia absorption method, which is based on the above-mentioned ammonia storage system.

[0042] Before loading and unloading ammonia water into the ammonia water storage tank 2 , a water inlet pipe 12 is installed at the water inlet N1 of the ammonia absorption tank 1 , and an air inlet pipe 13 is installed at the air inlet N3 .

[0043] Water is injected into the ammonia absorption tank 1 through the water inlet pipe 12, so that the water is injected into the upper liquid storage space 7 and the lower liquid storage space 8. The water injection process is as follows: open the manual valve on the water injection pipe, and water enters the upper liquid storage space 7 through the water inlet N1 and the water inlet pipe 12. After the upper liquid 14 is filled, the water overflows from the inner tube 4 into the lower liquid storage space 8. When the lower liquid 15 reaches a certain level, it will overflow through the partition 2. The overflowing water will pass through the connecting pipe after the overflow port N5, overcome the pressure of the U-shaped bend 10, and enter the ammonia storage tank 2. At this time, water can be observed passing through the glass sight glass 11, which indicates that the water injection of the ammonia absorption tank is complete. Close the water injection valve.

[0044] After the ammonia absorption tank 1 is filled with water, ammonia water can be injected into the ammonia water storage tank 2. During the process of ammonia water being injected into the ammonia water storage tank 2, the volatilized waste ammonia gas enters the ammonia absorption tank 1 through the connecting pipe between the waste ammonia gas outlet N9 and the ammonia gas inlet N2 of the ammonia absorption tank. The waste ammonia gas is absorbed by the upper liquid 14 and the lower liquid 15 in the ammonia absorption tank 1. After the liquid absorbs the waste ammonia gas, it becomes waste ammonia liquid. After the amount of waste ammonia liquid reaches a preset value, it enters the ammonia water storage tank through the connecting pipe between the overflow port N5 and the waste ammonia water inlet N11. Then, as the ammonia water pump is turned over, it enters the denitrification reaction zone, avoiding the waste of waste ammonia water. During this process, because the air inlet N3 and the inner cylinder 4 are both inserted below the liquid level, the gaseous ammonia cannot escape into the atmosphere from the exhaust port, which effectively solves the ammonia odor problem in the ammonia area.

[0045] After ammonia storage tank 2 is filled with ammonia, the liquid level in ammonia storage tank 2 decreases over time, potentially creating a negative pressure inside ammonia storage tank 2. This pressure also applies to ammonia absorption tank 1, which is connected to it via a pipeline. External air enters ammonia absorption tank 1 through air inlet pipe 13 and then passes through the connecting pipe between ammonia inlet port N2 and waste ammonia outlet port N9 into ammonia storage tank 2, thereby breaking the vacuum in ammonia absorption tank 1 and ammonia storage tank 2 and maintaining both tanks at normal pressure.

[0046] After the ammonia absorption tank 1 has been used for a period of time, open the manual ball valve on the connecting pipes of the drain port N6 and the emptying port N7 to drain the waste liquid in the ammonia absorption tank 1 into the ammonia water storage tank 2, then open the water injection valve and inject water into the ammonia water absorption tank 1 to achieve the replacement of the liquid in the ammonia absorption tank 1.

[0047] The water injected into the ammonia absorption tank 1 in the embodiment of the present invention is preferably fresh process water or demineralized water.

[0048] The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various variations and modifications. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A waste ammonia absorption device, characterized in that: The invention comprises an ammonia absorption tank (1), wherein the ammonia absorption tank (1) comprises a tank body (3), an inner cylinder (4), a first partition plate (5) and a second partition plate (6); The inner cylinder (4) is a hollow structure and is longitudinally arranged in the middle of the tank body (3). A gap is left between the top of the inner cylinder (4) and the top of the tank body (3), and between the bottom of the inner cylinder (4) and the bottom of the tank body (3). The first partition (5) is an annular structure and is fixedly connected between the inner wall of the tank body (1) and the outer wall of the inner cylinder (4). An upper liquid storage space (7) is formed on the upper part of the first partition (5). The second partition (6) is vertically fixed to the inner bottom surface of the tank body (3); the top end of the second partition (6) is higher than the bottom end of the inner tube (4) and is located outside the inner tube (4); a lower liquid storage space (8) is formed on the side of the second partition (6) facing the inner tube (4); and an overflow space (9) is formed on the side of the second partition (6) facing away from the inner tube (4); The top of the tank body (3) is provided with a water inlet (N1) and an ammonia inlet (N2); a drain outlet (N6) is provided on the side wall of the tank body (3) corresponding to the bottom of the upper liquid storage space (7); an emptying outlet (N7) is provided on the side wall of the tank body (3) corresponding to the bottom of the lower liquid storage space (8); and an overflow outlet (N5) is provided on the side wall of the tank body (3) corresponding to the bottom of the overflow space (9).

2. The ammonia absorption device according to claim 1, characterized in that: An air inlet (N3) is also provided at the top of the tank body (3), and a gas outlet (N4) is provided on the side wall of the tank body (3) below the first baffle (5), and the distance between the gas outlet (N4) and the bottom of the tank body (3) is higher than the height of the second baffle (6).

3. The ammonia absorption device according to claim 1, characterized in that: The height difference between the top end of the second partition plate (6) and the bottom end of the inner tube (4) is 50 mm.

4. An ammonia water storage system, characterized in that: It comprises an ammonia water storage tank (2) and the ammonia absorption device (1) according to claim 2 or 3; The ammonia water storage tank (2) is provided with an ammonia water inlet (N8), a waste ammonia outlet (N9), a sewage inlet (N10), and a waste ammonia water inlet (N11); wherein the waste ammonia outlet (N9) is connected to the ammonia inlet (N2) of the ammonia absorption tank (1) via a pipeline, the waste ammonia water inlet (N11) is connected to the overflow port (N5) of the ammonia absorption tank (1) via a pipeline, and the sewage inlet (N10) is connected to the drain port (N6) and the emptying port (N7) of the ammonia absorption tank (1) via a pipeline.

5. The ammonia water storage system according to claim 4, characterized in that: A U-shaped bend (10) is provided on the connecting pipe between the waste ammonia water inlet (N11) and the overflow port (N5).

6. The ammonia water storage system according to claim 5, characterized in that: A glass sight glass (11) is provided on the connecting pipe at the rear of the U-shaped bend (10).

7. A method for absorbing waste ammonia, characterized in that: The ammonia water storage system according to any one of claims 4 to 6 comprises the following steps: A water inlet pipe (12) is installed at the water inlet (N1) of the ammonia absorption tank (1), and an air inlet pipe (13) is installed at the air inlet (N3); water is injected into the ammonia absorption tank (1) through the water inlet pipe (12), so that the water is injected into the upper liquid storage space (7) and the lower liquid storage space (8); Ammonia water is injected into the ammonia water storage tank (2), and the volatilized waste ammonia gas enters the ammonia absorption tank (1) through the connecting pipe between the waste ammonia gas outlet (N9) and the ammonia gas inlet (N2) of the ammonia absorption tank. The waste ammonia gas is absorbed by the upper liquid and the lower liquid in the ammonia absorption tank. After the liquid absorbs the waste ammonia gas, it becomes waste ammonia liquid. After the amount of the waste ammonia liquid reaches a preset value, it enters the ammonia water storage tank through the connecting pipe between the overflow port (N5) and the waste ammonia water inlet (N11).

8. The waste ammonia absorption method according to claim 7, characterized in that: When the ammonia water storage tank (2) is filled with ammonia water, outside air enters the ammonia absorption tank (1) through the air inlet pipe (13), and enters the ammonia water storage tank (2) through the connecting pipe between the ammonia inlet (N2) and the waste ammonia outlet (N9), thereby breaking the vacuum state of the ammonia absorption tank (1) and the ammonia water storage tank (2), and maintaining the two storage tanks at a normal pressure state at all times.

9. The method for absorbing waste ammonia according to claim 7 or 8, characterized in that: After the ammonia absorption tank (1) has been used for a period of time, the drain port (N6) and the emptying port (N7) are opened to drain the waste liquid in the ammonia absorption tank (1) into the ammonia water storage tank (2), and then water is injected into the ammonia water absorption tank (1) to achieve replacement of the liquid in the ammonia absorption tank (1).

10. The waste ammonia absorption method according to claim 9, characterized in that: Two small holes are formed on the side wall of the water inlet pipe (12).

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