Ammonia gas absorption system capable of being released in large scale

Abstract

The utility model provides a large-scale release ammonia gas absorption system which comprises a primary absorber and a secondary absorber which are connected in series through an ammonia gas channel, a primary ammonia water tank and a secondary ammonia water tank which are respectively used for collecting products of the primary absorber and the secondary absorber, a water injection pipe and a collecting pipe for conveying ammonia gas. According to the technical scheme, the technical problem that the absorption capacity of an existing ammonia absorption system cannot cope with the large-release-amount ammonia gas generated when ammonia equipment of a large liquid ammonia storage tank is overhauled and purged, or a safety valve leaks internally, or accidents such as fire disasters and system overpressure occur is solved; the technical purpose of rapid and automatic switching between conventional normative ammonia water production and accident emergency treatment absorption is achieved, and the technical defects that in the prior art, due to insufficient absorption capacity, the operation mode is single, and functions are incomplete are overcome.

Description

Technical Field

[0001] This patent application relates to a gas absorption system that absorbs certain harmful gases through water dissolution and obtains the corresponding aqueous solution at the same time, such as an ammonia absorption system. It can also be used for but not limited to the absorption of harmful gases such as hydrochloric acid gas and chlorine gas. Background Art

[0002] The following is a comprehensive technical description using only ammonia absorption as an example.

[0003] At present, the industrial ammonia absorption and ammonia water preparation methods mainly adopt the water absorption method. The preparation process using the ammonia gas delivery pipe directly inserted into the water body has the problems of small absorption area, ammonia gas bubbles overflowing into the atmosphere to pollute the environment, and even explosion hazard in serious cases; manual operation is required to randomly test the ammonia water concentration during the preparation process, and the existing conventional process methods have the technical problems of high manual dependence and inability to timely reflect whether the saturation concentration has been reached, making it difficult to achieve the purpose of automated continuous production.

[0004] Patent document CN 104307315A discloses an ammonia absorption device and an absorption system containing the ammonia absorption device. The ammonia introduced into the inner cylinder is finely mixed with the water mist sprayed into the inner cylinder to form ammonia water that enters the ammonia water tank, and then circulates by the pump until the specified concentration is reached, and then a qualified ammonia water product is output. This technical solution is mainly suitable for the production and operation of indexed ammonia water industrial production or the absorption of ammonia byproducts in industrial production. Although it has the technical advantages of small footprint, economic applicability, and high ammonia absorption capacity, its normal operation is based on relatively strict technical standardization indicators. It cannot meet the absorption requirements for a sudden increase in the amount of ammonia released, especially due to safety accidents. Summary of the invention

[0005] The invention purpose of this patent application is to solve the technical problem that the existing toxic or combustible gas absorption devices have insufficient absorption capacity, and are particularly difficult to cope with the sudden increase in the release volume of toxic or combustible gases caused by safety accidents such as fire leakage, and to provide a large-scale ammonia absorption system that can effectively exert its absorption capacity even when the release volume suddenly increases, and resolve the harmful spread of toxic or combustible gases caused by accidents and other reasons.

[0006] The patent application provides a large-scale ammonia absorption system. The technical solution has the following main technical contents: a large-scale ammonia absorption system, which comprises a water injection pipe, a collection pipe for conveying ammonia, a primary absorber and a secondary absorber connected in series with an ammonia channel, and a primary ammonia water tank and a secondary ammonia water tank for collecting the products of the primary absorber and the secondary absorber, respectively, and a pressure transmitter is provided on the ammonia channel;

[0007] The primary absorber has an ammonia flow pipe with a water-injected outer interlayer as the main body, flanges with at least a manhole at the front end are installed at both ends of the ammonia flow pipe, the air hole of the front flange is connected to the collecting pipe, the air hole of the rear flange is directly connected to the inner cylinder of the secondary absorber, and the bottom of the ammonia flow pipe is connected to the primary ammonia water tank through the primary downpipe; a plurality of atomizing nozzles are arranged on the wall of the ammonia flow pipe corresponding to the water-injected outer interlayer, the water injection pipe is connected to the water injection outer interlayer, and the water injection pipe section is provided with a first control valve;

[0008] The secondary absorber is an ammonia absorber disclosed in publication number CN 104307315A, the bottom of the ammonia water collection chamber of which is connected to a secondary ammonia water tank via a secondary downpipe, and a return pipe of the secondary ammonia water tank is connected to a circulating water circuit of an outer cylinder provided with a circulating pump.

[0009] One preferred option of the above overall technical solution is that the pressure transmitter includes a primary pressure transmitter on the manifold and a secondary pressure transmitter on the ammonia direct pipeline between the primary absorber and the secondary absorber.

[0010] One preferred option of the above overall technical solution is that the detection range of the primary pressure transmitter is 10-16 times the detection range of the secondary pressure transmitter.

[0011] One of the preferred options of the above overall technical solution is that the secondary ammonia water tank is provided with a water supply pipe for replenishing fresh water, and the water supply pipe is provided with a second control valve.

[0012] One of the preferred options of the above overall technical solution is that an ammonia water delivery pipe is connected between the primary ammonia water tank and the secondary ammonia water tank, and an ammonia water lifting pump is provided on the delivery pipe.

[0013] The technical solution of the large-scale ammonia absorption system disclosed in this patent application solves the technical problem that the absorption capacity of the existing ammonia absorption system is unable to cope with the large amount of ammonia released when a large liquid ammonia storage tank is undergoing maintenance and purging of ammonia equipment, or when a safety valve leaks, or when an accident such as a fire or system overpressure occurs. It effectively improves its ammonia absorption performance and achieves the technical purpose of rapid and automatic conversion between conventional standardized ammonia water production and accident emergency treatment absorption. It uses a reliable system composition to make up for the lack of accident emergency treatment capability in existing technologies and eliminates the technical defects of existing technologies such as a single operating mode and incomplete functions due to insufficient absorption capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a block diagram of the system composition of this patent application.

[0015] Figure 2 This is a cross-sectional view of the structure of the primary absorber.

[0016] Figure 3 and Figure 4They are the structural sectional view and cross-sectional view of the secondary absorber respectively.

[0017] Figure 5 This is the structural diagram of the diffuser plate. DETAILED DESCRIPTION

[0018] The following will elaborate on the technical content of the large-scale ammonia absorption system of this patent application and explain its application technical effects.

[0019] The ammonia absorption system capable of large-scale discharge of the present patent application, such as Figure 1 The system structure shown in the figure includes a water injection pipe 35, a collecting pipe 36 for introducing ammonia, a primary absorber 31 and a secondary absorber 32 connected in series with an ammonia channel, and also includes a primary ammonia water tank 33 and a secondary ammonia water tank 34 for collecting the products of the primary absorber 31 and the secondary absorber 32 respectively. A pressure transmitter is provided on the ammonia channel.

[0020] The primary absorber 31 is a large-volume ammonia absorption device. Its structure is as follows: Figure 2 As shown, the main body is an ammonia flow pipe 321 with a water injection outer interlayer 322. At least a flange with a manhole 310 at the front end is installed at both ends of the ammonia flow pipe 321. The air hole of the front flange 323 is connected to the collecting pipe 36, and the air hole of the rear flange 324 is directly connected to the inner cylinder of the secondary absorber 32; the first-level downpipe 325 at the bottom of the ammonia flow pipe 321 is connected to the first-level ammonia water tank 33. On the wall of the ammonia flow pipe corresponding to the water injection outer interlayer 322, a plurality of atomizing nozzles are evenly distributed. The water injection pipe 35 is connected to a plurality of water supply pipes 30 evenly arranged on the water injection outer interlayer 322 through a branch pipeline.

[0021] Especially for emergency use in case of fire, system overpressure and other leakage accidents, the water injection pipe 35 is connected to the fire water pipe, and a first control valve 19 is provided on the pipe section of the water injection pipe 35.

[0022] The secondary absorber 32 adopts the ammonia absorber disclosed in publication number CN 104307315A as a conventional gas flow ammonia water production device. Figure 3-Figure 5 As shown, it is composed of an inner tube 1 and an outer tube 2 which are nested inside and outside. The front end of the inner tube 1 is connected to the ammonia flow pipe 321 of the primary absorber 1. A plurality of diffusers 3 are arranged at equal intervals in the inner tube 1. The diffusers 3 are evenly distributed with airflow deceleration holes 30 for dispersing the airflow to improve the ammonia absorption efficiency. The space surrounded by the outer tube 2 in the inner tube 1 is divided into a water injection space 10 above and an ammonia water collection chamber 20 below. The ammonia water collection chamber 20 is connected to the secondary ammonia water tank 34 through a secondary downpipe 40.

[0023] The outer cylinder 2 is provided with a water injection interface 4. In this embodiment, according to the actual demand for producing ammonia water in a cyclic operation, a fresh water replenishment pipe 44 is connected to the secondary ammonia water tank 34, and a second control valve 18 is provided on the replenishment pipe 44.

[0024] A return pipe 41 is provided between the secondary ammonia water tank 34 and the water injection space 10 of the secondary absorber 32. Driven by the circulating pump 50, the low-concentration ammonia water or make-up water in the secondary ammonia water tank 34 is sprayed into the inner tube 1 through the nozzle 5, absorbs the ammonia gas in the inner tube 1 to form ammonia water, and then enters the ammonia water collecting chamber 20, and flows into the diode ammonia water tank 34 through the secondary downpipe 40, forming a circulating water circuit for ammonia absorption. Driven by the circulating pump 50, ammonia is absorbed until the specified concentration or saturation concentration level required for output is reached.

[0025] In this embodiment, an ammonia water delivery pipe 43 is connected between the primary ammonia water tank 33 and the secondary ammonia water tank 34 , and an ammonia water delivery pump is provided on the ammonia water delivery pipe 43 .

[0026] The pressure transmitter in the system includes a primary pressure transmitter 37 arranged on the collecting pipe 36 in front of the primary absorber 31 , and also includes a secondary pressure transmitter 38 on the ammonia channel between the primary absorber 31 and the secondary absorber 32 .

[0027] The primary absorber 1 is mainly used as a large-displacement primary ammonia absorption device for the maintenance and purging of ammonia equipment, internal leakage of safety valves, or fire, system overpressure and other leakage accidents; the secondary absorber 32 is an ammonia water production device with a conventional gas flow. Therefore, the detection range of the primary pressure transmitter 37 is preferably a pressure detector that is 10-16 times larger than the detection range of the secondary pressure transmitter 38. For example, the maximum range of the primary pressure transmitter 37 is 16KPa, and the maximum range of the secondary pressure transmitter 38 is 1KPa.

[0028] The practical principle process is: when the system is used as an ammonia water production system with a normal gas flow rate, when the gas flow pressure in the ammonia channel does not reach the detection range of the primary pressure transmitter 37, the first control valve 19 remains closed. At this time, the electronic control unit detects through the secondary pressure transmitter 38 that when the pressure has reached the absorption start setting value, such as 0.3KPa, it is considered that ammonia has entered, and the circulation pump 50 and the second control valve 18 are automatically started to enter the ammonia water production operation mode of ammonia absorption. When it is necessary to implement ammonia equipment maintenance and purging, or safety valve internal leakage, or leakage accidents such as fire and system overpressure, resulting in a large amount of ammonia, the electronic control unit has detected that the limited starting pressure value has been reached or exceeded through the primary pressure transmitter 37, and the program immediately executes the following actions: open the first control valve 19, and a large amount of fresh water is sprayed into the ammonia flow pipe 321 to implement emergency ammonia absorption, and the unsaturated ammonia water obtained flows into the primary ammonia water tank 33 by gravity; after passing through the primary absorber 31, the ammonia in the airflow has been greatly reduced, and the residual ammonia enters the secondary absorber 32, and continues until it is completely absorbed, and the remaining nitrogen in the airflow is discharged through the venting pipeline. A bursting disc is provided on the venting pipeline of the primary absorber 31, and the actual protection set pressure can be selected as 30KPa.

[0029] The unsaturated ammonia water in the primary ammonia water tank 33 enters the secondary ammonia water tank 34 through the ammonia water delivery pipe 45 and the ammonia water lifting pump, so that the secondary ammonia water tank 34 becomes an emergency expansion storage container for ammonia water.

[0030] When the emergency treatment is coming to an end, when the electronic control unit detects that the gas flow pressure is lower than the specified starting pressure value through the first-level pressure transmitter 37, such as lower than 1.2KPa, the program immediately executes the following actions: close the first control valve 19, start the second control valve 18, and enter the ammonia production mode with normal gas flow.

Claims

1. A large-scale ammonia absorption system, the system comprising a water injection pipe (35), a manifold (36) for conveying ammonia, a primary absorber (31) and a secondary absorber (32) connected in series with an ammonia channel, and a primary ammonia water tank (33) and a secondary ammonia water tank (34) for collecting products of the primary absorber (31) and the secondary absorber (32), respectively, wherein a pressure transmitter is provided on the ammonia channel; The primary absorber (31) has a main body of an ammonia flow pipe (321) with a water injection outer interlayer (322). Flanges with at least a front end having a manhole are installed at both ends of the ammonia flow pipe (321). The air through hole of the front flange (323) is in communication with the collecting pipe (36), and the air through hole of the rear flange (324) is directly connected to the secondary absorber inner tube (1). The bottom of the ammonia flow pipe (321) is in communication with the primary ammonia water tank (33) via a primary downpipe (325). A plurality of atomizing nozzles are arranged on the wall of the ammonia flow pipe corresponding to the water injection outer interlayer (322). The water injection pipe (35) is in communication with the water injection outer interlayer (322), and a first control valve (19) is arranged on the water injection pipe section. The secondary absorber (32) is an ammonia absorber disclosed in publication number CN 104307315A, wherein the bottom of the ammonia water collection chamber (20) is connected to the secondary ammonia water tank (34) via a secondary downpipe (40), and a return pipe (41) of the secondary ammonia water tank is connected to the circulating water circuit of the outer cylinder and a circulating pump (50) is provided.

2. The ammonia absorption system capable of large-scale release according to claim 1, characterized in that: The pressure transmitter comprises a primary pressure transmitter (37) on the manifold and a secondary pressure transmitter (38) on the ammonia direct pipeline between the primary absorber (31) and the secondary absorber (32).

3. The large-scale ammonia absorption system according to claim 2, characterized in that: The detection range of the primary pressure transmitter (37) is 10-16 times the detection range of the secondary pressure transmitter (38).

4. The ammonia absorption system capable of large-scale release according to claim 1, characterized in that: The secondary ammonia water tank (34) is provided with a water supply pipe (44) for supplying fresh water, and a second control valve (18) is provided on the water supply pipe (44).

5. The ammonia absorption system capable of large-scale release according to claim 1, characterized in that: An ammonia water delivery pipe is connected between the primary ammonia water tank (33) and the secondary ammonia water tank (34), and an ammonia water lifting pump is arranged on the delivery pipe.

Images