Denitration ammonia-air mixing equipment capable of accurately controlling ammonia-air mixing ratio

Abstract

The utility model discloses denitration ammonia-air mixing equipment capable of accurately controlling the ammonia-air mixing ratio, which comprises an ammonia water buffer tank, an ammonia water evaporator, an ammonia-air mixer and an SCR (Selective Catalytic Reduction) reactor which are combined into a whole, the ammonia water buffer tank is connected with the ammonia water evaporator through an ammonia water conveying pump pry and a delivery pipe, the delivery pipe is also provided with a metering module for detecting ammonia gas, the metering module is a flow meter, the ammonia water evaporator is connected with the ammonia-air mixer through a through pipe, and an ammonia spraying grid communicated with the through pipe is fixed in the ammonia-air mixer. According to the denitration ammonia-air mixing equipment capable of accurately controlling the ammonia-air mixing ratio, hot air required by pyrolysis can be prevented from bringing extra oxygen into original flue gas, the cost of using other gas as dilution air is saved, two purposes are achieved at a time, and the ammonia-air mixing ratio can be accurately controlled under the condition of small flow.

Description

Technical Field

[0001] The utility model belongs to the technical field of ammonia-air mixing equipment, and in particular relates to a denitrification ammonia-air mixing equipment capable of accurately controlling the ammonia-air mixing ratio. Background Art

[0002] At present, in the process of treating flue gas generated in industrial production, ammonia is needed to react with harmful components in the flue gas to produce harmless or low-harm products. Nowadays, selective catalytic denitrification (SCR) is usually the main means to reduce NOx. The reducing agent ammonia is injected into the flue gas. Under the action of low-temperature catalyst, it selectively reacts with NOx in the flue gas to generate nitrogen and water, thereby achieving environmentally friendly emissions.

[0003] In the process of realizing the utility model, the inventor found that there are at least the following problems in the technology: ammonia water needs to be diluted after evaporating into high-concentration ammonia vapor. According to the specification, the ammonia-air mixed gas of the SCR reactor needs to be reduced to ammonia-air mixing ratio below 5% before entering the SCR reactor. Under the premise of ensuring that the system pressure and ammonia-air mixing ratio are reduced to below 5%, the required dilution air volume is calculated to be Q=300m3 / h. If compressed air or nitrogen is used as the source of dilution air, it is also necessary to heat the compressed air or nitrogen, and the use of compressed air will significantly affect the oxygen content of the flue gas of the entire system.

[0004] To this end, we proposed a denitrification ammonia-air mixing equipment that can accurately control the ammonia-air mixing ratio to solve the above problems. Utility Model Content

[0005] The main purpose of the utility model is to provide a denitrification ammonia-air mixing equipment for accurately controlling the ammonia-air mixing ratio, which can not only avoid the hot air required for pyrolysis from bringing additional oxygen into the original flue gas, but also save the cost of using the remaining gas as dilution air, killing two birds with one stone, and can accurately control the ammonia-air mixing ratio at a small flow rate, which can effectively solve the problems in the background technology.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A denitrification ammonia-air mixing device for accurately controlling the ammonia-air mixing ratio, comprising an ammonia buffer tank, an ammonia evaporator, an ammonia-air mixer and an SCR reactor, wherein an ammonia delivery pump skid is installed on the ammonia buffer tank, an external delivery pipe is installed on the ammonia delivery pump skid, and the ammonia buffer tank is connected to the ammonia evaporator through the ammonia delivery pump skid and the external delivery pipe, and a metering module for detecting ammonia is also installed on the external delivery pipe, and the metering module is a flow meter;

[0008] The ammonia water evaporator and the ammonia-air mixer are connected by a central through pipe, wherein an ammonia spray grid connected to the central through pipe is fixed in the ammonia-air mixer, and a plurality of nozzles distributed at equal intervals are connected below the ammonia spray grid, and a drainage fan is connected to the side of the ammonia-air mixer facing away from the ammonia water evaporator, wherein the ammonia-air mixer and the SCR reactor are connected by a flue pipe.

[0009] As a preferred embodiment, an input pipe is fixedly connected to the outer wall of the ammonia water buffer tank; the denitrification reducing agent can be input through the input pipe, and the denitrification reducing agent is 8% ammonia water solution.

[0010] As a preferred embodiment, one end of the external delivery pipe is connected to the ammonia water buffer tank, and the other end thereof is connected to the ammonia water evaporator; thereby, a connection is established between the ammonia water buffer tank and the ammonia water evaporator using the external delivery pipe.

[0011] As a preferred embodiment, a bracket is fixedly welded on the external delivery pipe, wherein the bracket is L-shaped and welded to the outer wall of the ammonia buffer tank; thereby, the structure of the external delivery pipe is reinforced by the bracket.

[0012] As a preferred embodiment, top support frames are symmetrically welded on both sides of the bottom wall of the ammonia injection grid, wherein the two top support frames are welded to the inner wall of the ammonia-air mixer, so that the structure of the ammonia injection grid remains stable.

[0013] As a preferred embodiment, a chimney is connected to the side of the SCR reactor facing away from the ammonia-air mixer to discharge the treated flue gas.

[0014] In summary, the technical effects and advantages of the utility model are as follows:

[0015] The denitrification ammonia-air mixing equipment, which can precisely control the ammonia-air mixing ratio, is equipped with an ammonia buffer tank to store 8% ammonia. The ammonia is pumped to the metering module through an ammonia delivery pump and then enters the ammonia evaporator for evaporation. The heat source of the ammonia evaporator is 1.2Mpa saturated steam. The ammonia vapor generated after the ammonia is evaporated enters the ammonia-air mixer and is mixed and diluted with the 150°C original flue gas from the SCR outlet drawn by the dilution fan, and then sprayed into the flue through the ammonia spray grid to react in the SCR reactor.

[0016] The denitrification ammonia-air mixing equipment can accurately control the ammonia-air mixing ratio. The dilution air source of this ammonia-air mixer adopts the 150°C raw flue gas from the SCR outlet drawn by the induced draft fan. This process route can not only avoid the hot air required for pyrolysis from bringing additional oxygen into the raw flue gas, but also save the cost of using the remaining gas as dilution air, killing two birds with one stone, and can accurately control the ammonia-air mixing ratio at a small flow rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0018] Figure 2 It is the front view of the utility model;

[0019] Figure 3 It is a partial cross-sectional view of the utility model;

[0020] Figure 4 For this utility model Figure 3 A magnified view of the structure at center;

[0021] Figure 5 This is a process flow chart of the utility model.

[0022] In the figure: 1. Ammonia buffer tank; 2. Ammonia evaporator; 3. Ammonia-air mixer; 4. SCR reactor; 5. Inlet pipe; 6. Ammonia delivery pump skid; 7. External delivery pipe; 8. Bracket; 9. Metering module; 10. Middle pipe; 11. Ammonia spray grid; 12. Nozzle; 13. Top support frame; 14. Drainage fan; 15. Flue pipe; 16. Chimney. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0024] Reference Figure 1-Figure 5 , a denitration ammonia-air mixing device for accurately controlling the ammonia-air mixing ratio, comprising an ammonia water buffer tank 1, an ammonia water evaporator 2, an ammonia-air mixer 3 and an SCR reactor 4 which are combined into one body, an input pipe 5 is fixedly connected to the outer wall of the ammonia water buffer tank 1, and a denitration reducing agent can be input through the input pipe 5, and the denitration reducing agent is an 8% ammonia solution (under the above premise, a process route of ammonia water evaporation + ammonia-air mixing + ammonia spraying grid + static mixer + SCR reactor is used), wherein an ammonia water delivery pump skid 6 is installed on the ammonia water buffer tank 1, an external delivery pipe 7 is installed on the ammonia water delivery pump skid 6, and the ammonia water buffer tank 1 is connected to the ammonia water evaporator 2 through the ammonia water delivery pump skid 6 and the external delivery pipe 7;

[0025] One end of the external delivery pipe 7 is connected to the ammonia buffer tank 1, and the other end thereof is connected to the ammonia evaporator 2, so that the external delivery pipe 7 is used to establish a connection between the ammonia buffer tank 1 and the ammonia evaporator 2. A bracket 8 is also fixedly welded on the external delivery pipe 7, wherein the bracket 8 is L-shaped and welded to the outer wall of the ammonia buffer tank 1, so that the structure of the external delivery pipe 7 is reinforced by the bracket 8. A metering module 9 for detecting ammonia is also installed on the external delivery pipe 7, and the metering module 9 is a flow meter;

[0026] The ammonia evaporator 2 and the ammonia-air mixer 3 are connected by a central through pipe 10, wherein an ammonia spray grid 11 communicating with the central through pipe 10 is fixed in the ammonia-air mixer 3, and a plurality of nozzles 12 distributed at equal intervals are connected below the ammonia spray grid 11, top support frames 13 are symmetrically welded on both sides of the bottom wall of the ammonia spray grid 11, wherein the two top support frames 13 are welded to the inner wall of the ammonia-air mixer 3, so that the structure of the ammonia spray grid 11 remains stable, and a draught fan 14 is connected to the side of the ammonia-air mixer 3 facing away from the ammonia evaporator 2, wherein the ammonia-air mixer 3 and the SCR reactor 4 are connected by a flue pipe 15, and a chimney 16 is connected to the side of the SCR reactor 4 facing away from the ammonia-air mixer 3 for discharging treated flue gas.

[0027] The denitrification ammonia-air mixing equipment with precise control of the ammonia-air mixing ratio: Before using it, it should be noted that the ammonia water needs to be diluted after evaporating into high-concentration ammonia vapor. According to the specification, the ammonia-air mixing ratio of the ammonia-air mixed gas in the SCR reactor 4 needs to be reduced to less than 5% before entering the SCR reactor 4;

[0028] In the prior art, under the premise of ensuring that the system pressure and the ammonia-air mixing ratio are reduced to less than 5%, the required dilution air volume is calculated to be Q = 300m3 / h. If compressed air or nitrogen is used as the source of dilution air, it is also necessary to heat the compressed air or nitrogen, and the use of compressed air will significantly affect the oxygen content of the flue gas in the entire system;

[0029] Therefore, in this technical solution, the dilution air source of the ammonia-air mixer 3 is the 150°C raw flue gas at the SCR outlet drawn by the induced draft fan 14. This process route can not only avoid the hot air required for pyrolysis from bringing extra oxygen into the raw flue gas, but also save the cost of using the remaining gas as dilution air, killing two birds with one stone, and can accurately control the ammonia-air mixing ratio at a small flow rate.

[0030] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A denitrification ammonia-air mixing device for accurately controlling the ammonia-air mixing ratio, comprising an ammonia water buffer tank (1), an ammonia water evaporator (2), an ammonia-air mixer (3) and an SCR reactor (4) which are integrated into one body, characterized in that: The ammonia water buffer tank (1) is equipped with an ammonia water delivery pump skid (6), an external delivery pipe (7) is installed on the ammonia water delivery pump skid (6), and the ammonia water buffer tank (1) is connected to the ammonia water evaporator (2) through the ammonia water delivery pump skid (6) and the external delivery pipe (7), and a metering module (9) for detecting ammonia gas is also installed on the external delivery pipe (7); The ammonia water evaporator (2) and the ammonia-air mixer (3) are connected via a central through pipe (10), wherein an ammonia spraying grid (11) communicating with the central through pipe (10) is fixed inside the ammonia-air mixer (3), and a plurality of nozzles (12) distributed at equal intervals are connected below the ammonia spraying grid (11), and a drainage fan (14) is connected to the side of the ammonia-air mixer (3) facing away from the ammonia water evaporator (2), wherein the ammonia-air mixer (3) and the SCR reactor (4) are connected via a flue pipe (15).

2. The denitrification ammonia-air mixing equipment for accurately controlling the ammonia-air mixing ratio according to claim 1, characterized in that: An input pipe (5) is fixedly connected to the outer wall of the ammonia water buffer tank (1).

3. The denitrification ammonia-air mixing equipment for accurately controlling the ammonia-air mixing ratio according to claim 1, characterized in that: One end of the external delivery pipe (7) is connected to the ammonia water buffer tank (1), and the other end thereof is connected to the ammonia water evaporator (2).

4. The denitrification ammonia-air mixing equipment for accurately controlling the ammonia-air mixing ratio according to claim 1, characterized in that: A bracket (8) is also fixedly welded to the external delivery pipe (7), wherein the bracket (8) is L-shaped and is welded to the outer wall of the ammonia water buffer tank (1).

5. The denitrification ammonia-air mixing equipment for accurately controlling the ammonia-air mixing ratio according to claim 1, characterized in that: Top support frames (13) are symmetrically welded to both sides of the bottom wall of the ammonia injection grid (11), wherein the two top support frames (13) are both welded to the inner wall of the ammonia-air mixer (3).

6. The denitrification ammonia-air mixing equipment for accurately controlling the ammonia-air mixing ratio according to claim 1, characterized in that: The side of the SCR reactor (4) facing away from the ammonia-air mixer (3) is connected to a chimney (16).

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