Experimental device and method for ammonia injection branch pipe in urea pyrolysis furnace for SCR denitration

Abstract

The present invention relates to the technical field of urea pyrolysis furnaces for SCR denitration, and in particular to an experimental device and method for an ammonia injection branch pipe in a urea pyrolysis furnace for SCR denitration. The device comprises: an ammonia gas branch pipe, wherein a sealing ring is provided at an connection port of the ammonia gas branch pipe; a spray gun nozzle; and a mounting mechanism, comprising a connector provided on the ammonia gas branch pipe, a first limiting assembly provided on the connector and used for connecting the ammonia gas branch pipe and the spray gun nozzle, an annular body provided on the connector, and a driving assembly provided on the annular body and used for working in conjunction with the first limiting assembly to realize sealing between the ammonia gas branch pipe and the spray gun nozzle. By means of the first limiting assembly, the ammonia gas branch pipe and the spray gun nozzle are quickly locked; by means of the driving assembly, the spray gun nozzle and the ammonia gas branch pipe can be adjusted, the sealing effect between the spray gun nozzle and the ammonia gas branch pipe is improved, costs are reduced and the replacement time is eliminated; and by means of a second limiting assembly, the driving assembly is quickly locked.

Description

SCR denitration urea pyrolysis furnace ammonia gas branch pipe experimental device and method TECHNICAL FIELD

[0001] The present application relates to the technical field of SCR denitration urea pyrolysis furnace, in particular to a SCR denitration urea pyrolysis furnace ammonia gas branch pipe experimental device and method. BACKGROUND

[0002] The denitration adopts secondary air to heat the urea solution to produce ammonia gas, the ammonia gas is injected into the flue by the ammonia injector and mixed with the flue gas, and then enters the reactor to react with NOX through the catalyst layer. The SCR system is installed after the boiler economizer and before the air preheater, and the concentration of NOX in the flue gas is reduced through the above reaction.

[0003] In the pyrolysis furnace, the urea solution is mixed with high-temperature secondary air by compressed air atomization, and the urea solution is atomized by three 316L stainless steel injectors and sprayed into the decomposition chamber. A single spray gun can deliver up to 50% urea solution at about 110L / h, and a single pyrolysis furnace can decompose urea at a maximum capacity of about 185kg / h. Fluctuations in compressed air directly affect atomization, and poor atomization leads to crystallization inside the pyrolysis furnace.

[0004] Due to the limited space of the boiler, the ammonia gas branch pipe is arranged with one long branch pipe and one short branch pipe, which results in a lower temperature at the end of the long ammonia gas branch pipe of the SCR denitration urea pyrolysis furnace, and often causes blockage of the ammonia injection branch pipe, uneven distribution of ammonia gas into the flue, difficulty in controlling nitrogen oxides, and forced shutdown of the SCR denitration system in severe cases.

[0005] To solve the above problems, the ammonia gas branch pipe needs to be researched. In the prior art, when the spray gun head is connected to the ammonia gas branch pipe, a quick connection device is usually used for connection. Although this connection method makes the installation and removal of the spray gun head and the ammonia gas branch pipe more convenient, the sealing of the sealing ring will decrease due to the corrosive nature of ammonia, and slight corrosion will cause gaps between the spray gun head and the ammonia gas branch pipe, resulting in ammonia leakage and experimental data errors. When the spray gun head is mass-produced, it cannot meet the experimental requirements, resulting in unusable gun heads and economic losses. Moreover, if the sealing ring is replaced every time the spray gun head is replaced, although it can effectively solve the problem of sealing, it will make the replacement process more troublesome. Therefore, a SCR denitration urea pyrolysis furnace ammonia gas branch pipe experimental device and method are proposed.

[0006] SUMMARY

[0007] In view of the above or prior art, using a quick connecting device to install the ammonia branch pipe and the lance head makes the installation and dismounting between the lance head and the ammonia branch pipe more convenient, but under the corrosion of ammonia, the sealing property of the sealing ring will continuously decrease, and slight corrosion will cause a gap between the lance head and the ammonia branch pipe, thereby causing ammonia to flow out, leading to errors in experimental data, when the lance head is mass produced, the produced lance head cannot be used due to failure to meet the experimental effect, causing economic losses, and if the sealing ring is replaced every time the lance head is replaced, the sealing problem can be effectively solved, but the replacement process is more troublesome.

[0008] Therefore, the purpose of the present application is to provide an SCR denitration urea pyrolysis furnace ammonia branch pipe experimental device.

[0009] To solve the above technical problems, the present application provides the following technical scheme: comprising,

[0010] An ammonia branch pipe is provided with a sealing ring at the interface;

[0011] A lance head;

[0012] An installation mechanism includes a connector provided on the ammonia branch pipe, a first limiting component provided on the connector for connecting the ammonia branch pipe and the lance head, an annular body provided on the connector, a driving component provided on the annular body for cooperating with the first limiting component to realize sealing between the ammonia branch pipe and the lance head, and a second limiting component provided on the ammonia branch pipe for locking the driving component.

[0013] As a preferred scheme of the SCR denitration urea pyrolysis furnace ammonia branch pipe experimental device of the present application, wherein: the first limiting component includes a first sliding groove opened on the connector, a first sliding block and a first spring provided inside the first sliding groove, one end of the first spring is connected with the inner wall of the first sliding groove, and the other end of the first spring is connected with the first sliding block, the top of the first sliding block extends out of the first sliding groove and is connected with a limiting block.

[0014] As a preferred scheme of the SCR denitration urea pyrolysis furnace ammonia branch pipe experimental device of the present application, wherein: the first limiting component further includes a first inclined surface provided on the lance head, and a second inclined surface provided on the limiting block.

[0015] As a preferred scheme of the SCR denitration urea pyrolysis furnace ammonia branch pipe experimental device of the present application, wherein: the driving component includes a protruding block provided on the annular body, a first arc surface provided on the protruding block, and a second arc surface provided on the limiting block.

[0016] As a preferred scheme of the SCR denitration urea pyrolysis furnace ammonia gas branch pipe experimental device of the application, wherein: the driving assembly further comprises a first surface provided on the limiting block, and a second surface provided on the lance head.

[0017] As a preferred scheme of the SCR denitration urea pyrolysis furnace ammonia gas branch pipe experimental device of the application, wherein: a positioning block is arranged on the annular body, and the side surface of the positioning block is a plane.

[0018] As a preferred scheme of the SCR denitration urea pyrolysis furnace ammonia gas branch pipe experimental device of the application, wherein: the second limiting assembly comprises a ring sleeve connected with the ammonia gas branch pipe, a second spring connected with the ring sleeve, and a sleeve connected with the end of the second spring away from the ring sleeve, wherein the sleeve is arranged on the ammonia gas branch pipe, and the first anti-skid pattern is arranged in the sleeve.

[0019] The first anti-skid pattern and the second anti-skid pattern are both multiple and are arranged in a ring shape at equal intervals.

[0020] As a preferred scheme of the SCR denitration urea pyrolysis furnace ammonia gas branch pipe experimental device of the application, wherein: a second sliding groove is arranged on the ammonia gas branch pipe, and a second sliding block is arranged in the second sliding groove and connected with the sleeve.

[0021] As a preferred scheme of the SCR denitration urea pyrolysis furnace ammonia gas branch pipe experimental device of the application, wherein: the second sliding groove and the second sliding block are matched in the moving track.

[0022] The SCR denitration urea pyrolysis furnace ammonia gas branch pipe experimental device of the application has the following beneficial effects: the first limiting assembly can quickly lock the ammonia gas branch pipe and the lance head, the driving assembly can extrude the lance head, and the sealing effect between the lance head and the ammonia gas branch pipe can be adjusted under the cooperation of the sealing ring, so that the sealing ring does not need to be replaced every time the lance head is replaced, the cost and replacement time are saved, and the driving assembly is quickly locked by the second limiting assembly.

[0023] To solve the above technical problems, the application further provides the following technical scheme: an experimental method for preventing crystallization of an ammonia branch pipe of an SCR denitration urea pyrolysis furnace, comprising an experimental device for the ammonia branch pipe of the SCR denitration urea pyrolysis furnace, and

[0024] Step one: under the existing system configuration, collect the concentration data of nitrogen oxides in flue gas;

[0025] Step two: connect the lance head and the ammonia pipeline by the mounting mechanism;

[0026] Step three: test the spray gun head of different spray ranges;

[0027] Step four: measure the concentration of nitrogen oxides in the flue gas under each pressure ratio, and record the hourly average value;

[0028] Step five: test the denitration efficiency under 2 and 3 layer catalyst configuration respectively, and ensure that the emission standard is met;

[0029] Step six: measure the dilution air volume and pressure under different catalyst layer configurations to evaluate the system performance;

[0030] Step seven: monitor the crystallization in the pyrolysis furnace and evaluate the crystallization risk and the relevance of the improved spray gun head.

[0031] The beneficial effects of the SCR denitration urea pyrolysis furnace ammonia injection branch pipe anti-crystallization experimental method of the present application are: spray atomization fan: the newly designed spray gun head can reduce the atomization fan by about 10-20 cm.

[0032] Urea solution consumption: under different pressure ratios, the urea solution consumption is kept within a reasonable range.

[0033] Nitrogen oxide concentration: by increasing the catalyst layer, the nitrogen oxide concentration is reduced to meet the ultra-low emission standard.

[0034] Dilution air volume and pressure: after increasing the catalyst layer, the air volume and pressure are reduced and kept within a safe operating range.

[0035] Crystallization: the new spray gun head design significantly reduces or eliminates the crystallization of the pyrolysis furnace. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0037] Figure 1 is a schematic diagram of the overall structure of the SCR denitration urea pyrolysis furnace ammonia injection branch pipe experimental device.

[0038] Figure 2 is a schematic diagram of the structure of the spray gun head and ammonia branch pipe connection of the SCR denitration urea pyrolysis furnace ammonia injection branch pipe experimental device.

[0039] Figure 3 is an enlarged schematic diagram of the structure of position A of Figure 2 of the SCR denitration urea pyrolysis furnace ammonia injection branch pipe experimental device.

[0040] Figure 4 is a schematic diagram of the structure of the spray gun head of the SCR denitration urea pyrolysis furnace ammonia injection branch pipe experimental device.

[0041] Figure 5 is a schematic diagram of the driving assembly structure of the ammonia injection branch pipe experimental device of the SCR denitration urea pyrolysis furnace.

[0042] Figure 6 is a schematic diagram of the second limiting assembly structure of the ammonia injection branch pipe experimental device of the SCR denitration urea pyrolysis furnace. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned objectives, features and advantages of the present application more apparent and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0044] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, therefore the present application is not limited by the specific embodiments disclosed below.

[0045] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an embodiment that is separate or alternative to other embodiments.

[0046] Embodiment 1, with reference to Figures 1-3, is the first embodiment of the present application, which provides an ammonia injection branch pipe experimental device of the SCR denitration urea pyrolysis furnace, which comprises an ammonia injection branch pipe 100, a sealing ring 101 provided at the interface thereof, a lance head 200, a mounting mechanism 300 comprising a connector 301 provided on the ammonia injection branch pipe 100, a first limiting assembly 302 provided on the connector 301 for connecting the ammonia injection branch pipe 100 and the lance head 200, an annular body 303 provided on the connector 301, a driving assembly 304 provided on the annular body 303 for cooperating with the first limiting assembly 302 to realize sealing between the ammonia injection branch pipe 100 and the lance head 200, and a second limiting assembly 305 provided on the ammonia injection branch pipe 100 for locking the driving assembly 304. After the ammonia injection branch pipe 100 and the lance head 200 are connected, the first limiting assembly 302 can realize quick locking between the ammonia injection branch pipe 100 and the lance head 200, the driving assembly 304 can extrude the lance head 200, and under the cooperation of the sealing ring 101, the sealing property between the lance head 200 and the ammonia injection branch pipe 100 can be adjusted, thereby increasing the sealing effect between the lance head 200 and the ammonia injection branch pipe 100, so that the sealing ring 101 does not need to be replaced every time the lance head 200 is replaced, saving cost and replacement time, and the second limiting assembly 305 realizes quick locking of the driving assembly 304.

[0047] Wherein, the ring body 303 is rotationally connected with the joint 301, and the two can be matched through a circular sliding slot and a sliding block, or can be connected through a bearing, as long as rotation between the two is ensured and the connection is not disconnected.

[0048] Further, the first limiting assembly 302 comprises a first sliding slot 302a provided on the joint 301, a first sliding block 302b and a first spring 302c are arranged in the first sliding slot 302a, one end of the first spring 302c is connected with the inner wall of the first sliding slot 302a, and the other end of the first spring 302c is connected with the first sliding block 302b, the top of the first sliding block 302b extends out of the first sliding slot 302a and is connected with a limiting block 302d, the first limiting assembly 302 further comprises a first inclined surface 302e provided on the spray gun head 200, and a second inclined surface 302f provided on the limiting block 302d, when the spray gun head 200 is installed, the first inclined surface 302e on the spray gun head 200 contacts with the second inclined surface 302f on the limiting block 302d, so that the limiting block 302d moves away from the center of the ammonia branch pipe 100, the limiting block 302d drives the first sliding block 302b to move, the first sliding block 302b drives the first spring 302c to be elongated, when the spray gun head 200 is inserted into a proper position, under the elastic force of the first spring 302c, the limiting block 302d resets, so that the limiting block 302d is clamped on the spray gun head 200, realizing the quick installation between the spray gun head 200 and the ammonia branch pipe 100.

[0049] Wherein, the first sliding slot 302a and the first sliding block 302b are both trapezoidal, and under the limitation of the first sliding slot 302a, the first sliding block 302b moves linearly, and under the limitation of the first sliding slot 302a and the first sliding block 302b, the resetting of the limiting block 302d is facilitated, so that the quick connection between the spray gun head 200 and the ammonia branch pipe 100 is realized.

[0050] Further, the driving assembly 304 further comprises a first surface 304d provided on the limiting block 302d, and a second surface 304e provided on the spray gun head 200, in this embodiment, the first surface 304d and the second surface 304e are both flat surfaces, when the limiting block 302d moves to a proper position, the first surface 304d on the limiting block 302d is attached to the second surface 304e on the spray gun head 200, realizing the connection between the spray gun head 200 and the ammonia branch pipe 100.

[0051] In use, when it is needed to install the spray gun head 200 on the ammonia branch pipe 100, the spray gun head 200 is aligned with the ammonia branch pipe 100 and inserted, the first inclined surface 302e on the spray gun head 200 is in contact with the second inclined surface 302f on the limiting block 302d, so that the limiting block 302d drives the first sliding block 302b to move away from the center of the ammonia branch pipe 100, the first sliding block 302b drives the first spring 302c to be stretched, when the first surface 304d on the limiting block 302d corresponds to the second surface 304e on the spray gun head 200, the limiting block 302d is reset under the elastic force of the first spring 302c, so that the limiting block 302d is clamped on the spray gun head 200, the first surface 304d on the limiting block 302d is in contact with the second surface 304e on the spray gun head 200, and the quick installation between the spray gun head 200 and the ammonia branch pipe 100 is realized.

[0052] Embodiment 2, referring to FIGS. 2-6, is a second embodiment of the present application, which is different from the previous embodiment in that the driving assembly 304 in this embodiment includes a protruding block 304a arranged on the annular body 303, a first arc surface 304b arranged on the protruding block 304a, and a second arc surface 304c arranged on the limiting block 302d.

[0053] Further, the driving assembly 304 further includes a first surface 304d arranged on the limiting block 302d and a second surface 304e arranged on the spray gun head 200, in this embodiment, the first surface 304d and the second surface 304e are both arc-shaped inclined surfaces, in the first embodiment, the limiting block 302d presses the second surface 304e through the first surface 304d, and the quick installation between the spray gun head 200 and the ammonia branch pipe 100 is realized.

[0054] Further, the annular body 303 is provided with a positioning block 303a located on one side of the protruding block 304a, and the side surface of the positioning block 303a is a plane.

[0055] When it is needed to replace the next spray gun head 200 for experiment, the spray gun head 200 is pulled out, at this time, the spray gun head 200 presses the first surface 304d on the limiting block 302d through the second surface 304e, so that the limiting block 302d moves away from the spray gun head 200, the limiting block 302d can drive the annular body 303 to rotate reversely and reset through the second arc surface 304c, the positioning block 303a is arranged to ensure that the annular body 303 can return to the initial position accurately, and in this embodiment, the first spring 302c can not be arranged, so that when the next spray gun head 200 is inserted, the next spray gun head 200 will not be in contact with the limiting block 302d, the wear of the limiting block 302d is reduced, the service life of the device is improved, and at the same time, the first spring 302c is not arranged, and the cost is saved.

[0056] Further, the annular body 303 is provided with a second anti-skid line 305e, which facilitates the rotation of the annular body 303 by the staff.

[0057] In use, the staff contacts the second anti-skid line 305e with the hand and drives the annular body 303 to rotate through the second anti-skid line 305e. The annular body 303 drives the convex block 304a to rotate, and the first arc surface 304b on the convex block 304a extrudes the second arc surface 304c on the limiting block 302d, so that the limiting block 302d approaches the center of the lance head 200, and the limiting block 302d drives the first spring 302c to be compressed. At the same time, the limiting block 302d extrudes the second surface 304e on the lance head 200 through the first surface 304d, so that the lance head 200 further approaches the ammonia branch pipe 100, thereby extruding the sealing ring 101, and the sealing ring 101 is deformed. By changing the rotation angle of the annular body 303, the sealing between the lance head 200 and the ammonia branch pipe 100 is adjusted, the sealing effect between the lance head 200 and the ammonia branch pipe 100 is improved, and when the sealing ring 101 is used for a long time and the sealing performance is reduced, the function can still maintain good sealing effect without replacing the sealing ring 101, thereby saving cost.

[0058] Embodiment 3, referring to FIGS. 3-6, is a second embodiment of the application. Different from the previous embodiment, the second limiting assembly 305 in this embodiment includes a ring sleeve 305a fixedly connected with the ammonia branch pipe 100, a second spring 305b fixedly connected with the ring sleeve 305a on the side close to the joint 301, the second spring 305b being sleeved on the ammonia branch pipe 100, and a sleeve 305c connected with the second spring 305b away from the ring sleeve 305a, the sleeve 305c being provided with a first anti-skid line 305d inside.

[0059] The first anti-skid line 305d and the second anti-skid line 305e are both multiple and annularly equidistantly distributed.

[0060] Further, the ammonia branch pipe 100 is provided with a second sliding groove 305f, and the second sliding groove 305f is provided with a second sliding block 305g inside, the second sliding block 305g being connected with the sleeve 305c. The second sliding groove 305f and the second sliding block 305g ensure that the sleeve 305c can only move linearly and cannot rotate, so that when the first anti-skid line 305d corresponds to the second anti-skid line 305e, the second anti-skid line 305e cannot rotate because the sleeve 305c cannot rotate, so that the first anti-skid line 305d cannot drive the annular body 303 to rotate, thereby achieving the locking of the annular body 303.

[0061] Further, the second sliding groove 305f matches the movement trajectory of the second sliding block 305g, that is, when the second sliding block 305g moves to the bottom of the second sliding groove 305f, the first anti-skid pattern 305d is completely misaligned with the second anti-skid pattern 305e, realizing the accurate unlocking of the annular body 303, and avoiding the excessive compression of the second spring 305b, which causes the damage of the second spring 305b. When the second sliding block 305g is in the initial position, the first anti-skid pattern 305d corresponds to the second anti-skid pattern 305e.

[0062] The remaining structures are the same as those in Embodiment 2.

[0063] In use, first push the sleeve 305c downward, the sleeve 305c drives the second spring 305b to be compressed, and at the same time, the sleeve 305c drives the second anti-skid pattern 305e to be misaligned with the first anti-skid pattern 305d. Then, the hand contacts the first anti-skid pattern 305d to drive the annular body 303 to rotate. When the seal between the lance head 200 and the ammonia branch pipe 100 is adjusted to be appropriate, the sleeve 305c is released, and under the action of the second spring 305b, the sleeve 305c resets, so that the first anti-skid pattern 305d in the sleeve 305c is interlaced with the second anti-skid pattern 305e on the annular body 303. Under the cooperation of the second sliding groove 305f and the second sliding block 305g, the annular body 303 rotates, realizing the locking of the annular body 303.

[0064] Embodiment 4 is a third embodiment of the present application, which is different from the previous embodiment. The embodiment provides an experimental method for preventing crystallization of an SCR denitration urea pyrolysis furnace ammonia injection branch pipe, which comprises,

[0065] Step one: under the existing system configuration, collect the concentration data of nitrogen oxides in flue gas;

[0066] Step two: connect the lance head 200 with the ammonia pipeline through the installation mechanism 300;

[0067] Step three: test the lance head 200 with different injection ranges;

[0068] Step four: under each pressure ratio, measure the concentration of nitrogen oxides in flue gas, and record the hourly average value;

[0069] Step five: under the configuration of 2 layers and 3 layers of catalysts, respectively test the denitration efficiency to ensure that the emission standard is met;

[0070] Step six: measure the dilution air volume and pressure under different catalyst layer configurations to evaluate the system performance;

[0071] Step seven: monitor the crystallization in the pyrolysis furnace, evaluate the crystallization risk, and evaluate the relevance of the improvement of the lance head 200.

[0072] The experimental data of the influence of compressed air pressure on the atomization effect of urea solution is as follows, including compressed air pressure, urea solution pressure, urea flow rate, and observed atomization effect:

[0073] Experimental data analysis:

[0074] In experiment No. 1, the compressed air pressure and the urea solution pressure are equal, both being 0.35 MPa. At this time, the urea solution cannot be atomized and presents a water column shape.

[0075] Experiment No. 2 shows that when the compressed air pressure increases to 0.40 MPa, although the urea solution pressure remains unchanged, the atomization effect is slightly improved, but still not good.

[0076] In experiments No. 3 and 4, as the compressed air pressure further increases to 0.45 MPa and 0.50 MPa, the atomization effect is significantly improved, and at 0.50 MPa, it reaches the best state.

[0077] When the compressed air pressure increases to 0.55 MPa (experiment No. 5), although the urea solution pressure remains at 0.35 MPa, the atomization effect begins to deteriorate, indicating that the compressed air pressure may have approached or exceeded the optimal range.

[0078] In experiment No. 6, the compressed air pressure reaches 0.60 MPa, and the urea solution appears to be backflowing, which cannot be normally sprayed, resulting in no atomization effect.

[0079] According to the modified experimental data, we can conclude that under the condition of urea solution pressure of 0.35 MPa, in order to achieve the best atomization effect of urea solution, the compressed air pressure should be adjusted to about 0.50 MPa. If the compressed air pressure is too low (such as 0.35 MPa), the urea solution cannot be atomized; if the pressure is too high (such as 0.60 MPa), it may cause the urea solution to backflow, which also cannot achieve atomization. These data further verify the importance of compressed air pressure in the atomization process and its direct influence on the atomization effect.

[0080] Based on the above experiments, further experiments are conducted:

[0081] Data analysis:

[0082] Spray atomization fan: The newly designed lance head 200 can reduce the atomization fan by about 10-20 cm;

[0083] Urea solution consumption: Under different pressure ratios, the urea solution consumption remains within a reasonable range;

[0084] NOx concentration: With the addition of catalyst layers, NOx concentration is reduced to meet ultra-low emission standards;

[0085] Dilution air volume and pressure: With the addition of catalyst layers, air volume and pressure are reduced, but remain within safe operating ranges;

[0086] Crystallization: The new lance tip 200 design significantly reduces or eliminates crystallization in the pyrolysis furnace.

[0087] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. An experimental apparatus for injecting ammonia gas into a branch pipe of an SCR denitrification urea pyrolysis furnace, characterized in that: include, Ammonia branch pipe (100) with a sealing ring (101) at its interface; Spray gun head (200); The installation mechanism (300) includes a connector (301) disposed on the ammonia branch pipe (100), a first limiting component (302) disposed on the connector (301) for connecting the ammonia branch pipe (100) and the spray gun head (200), an annular body (303) disposed on the connector (301), a drive component (304) disposed on the annular body (303) for cooperating with the first limiting component (302) to seal between the ammonia branch pipe (100) and the spray gun head (200), and a second limiting component (305) disposed on the ammonia branch pipe (100) for locking the drive component (304).

2. The experimental apparatus for injecting ammonia gas into the branch pipe of the SCR denitrification urea pyrolysis furnace as described in claim 1, characterized in that: The first limiting component (302) includes a first groove (302a) formed on the connector (301), a first slider (302b) and a first spring (302c) disposed inside the first groove (302a). One end of the first spring (302c) is connected to the inner wall of the first groove (302a), and the other end of the first spring (302c) is connected to the first slider (302b). The top of the first slider (302b) extends out of the first groove (302a) and is connected to a limiting block (302d).

3. The experimental apparatus for injecting ammonia gas into the branch pipe of the SCR denitrification urea pyrolysis furnace as described in claim 2, characterized in that: The first limiting component (302) further includes a first inclined surface (302e) disposed on the spray gun head (200) and a second inclined surface (302f) disposed on the limiting block (302d).

4. The experimental apparatus for injecting ammonia gas into the branch pipe of the SCR denitrification urea pyrolysis furnace as described in claim 3, characterized in that: The driving component (304) includes a protrusion (304a) on the annular body (303), a first arc surface (304b) on the protrusion (304a), and a second arc surface (304c) on the limiting block (302d).

5. The experimental apparatus for injecting ammonia gas into the branch pipe of the SCR denitrification urea pyrolysis furnace as described in claim 4, characterized in that: The drive assembly (304) further includes a first surface (304d) disposed on the limiting block (302d) and a second surface (304e) disposed on the spray gun head (200).

6. The experimental apparatus for injecting ammonia gas into the branch pipe of the SCR denitrification urea pyrolysis furnace as described in claim 5, characterized in that: A positioning block (303a) is provided on the annular body (303), and the side of the positioning block (303a) is a plane.

7. The experimental apparatus for injecting ammonia gas into the branch pipe of the SCR denitrification urea pyrolysis furnace as described in claim 5 or 6, characterized in that: The second limiting component (305) includes a ring (305a) connected to the ammonia branch pipe (100), a second spring (305b) connected to the ring (305a), the second spring (305b) being sleeved on the ammonia branch pipe (100), and a sleeve (305c) connected to one end of the second spring (305b) away from the ring (305a), the sleeve (305c) having a first anti-slip texture (305d) inside, and a second anti-slip texture (305e) on the annular body (303); There are multiple first anti-slip patterns (305d) and second anti-slip patterns (305e), and they are all distributed in a ring at equal intervals.

8. The experimental apparatus for injecting ammonia gas into the branch pipe of the SCR denitrification urea pyrolysis furnace as described in claim 7, characterized in that: The ammonia branch pipe (100) is provided with a second sliding groove (305f), and a second slider (305g) is provided inside the second sliding groove (305f). The second slider (305g) is connected to the sleeve (305c).

9. The experimental apparatus for injecting ammonia gas into the branch pipe of the SCR denitrification urea pyrolysis furnace as described in claim 8, characterized in that: The second slide (305f) matches the movement trajectory of the second slider (305g).

10. A method for preventing crystallization in the ammonia injection branch pipe of an SCR denitrification urea pyrolysis furnace, characterized in that: The experimental apparatus for injecting ammonia gas into the branch pipe of the SCR denitrification urea pyrolysis furnace as described in any one of claims 1 to 9, and, Step 1: Under the existing system configuration, collect the concentration data of nitrogen oxides in the flue gas; Step 2: Connect the spray gun head (200) to the ammonia gas pipeline via the installation mechanism (300); Step 3: Test the spray gun head (200) with different spray ranges; Step 4: Under each pressure ratio, measure the concentration of nitrogen oxides in the flue gas and record the hourly average value; Step 5: Test the denitrification efficiency with 2-layer and 3-layer catalyst configurations respectively to ensure that emission standards are met; Step 6: Measure the dilution airflow and pressure under different catalyst layer configurations to evaluate system performance; Step 7: Monitor the crystallization situation inside the pyrolysis furnace and assess the correlation between crystallization risk and improvements to the spray gun head (200).

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