Double-fluid mixing spray gun and using method thereof

Abstract

The invention belongs to the technical field of spray guns, and relates to a double-fluid mixing spray gun and a using method thereof. Impurities in a urea solution and solid particles such as undissolved urea are filtered through the filtering unit, and the solid particles are prevented from blocking a pipeline and a nozzle in the gas-liquid mixing pipeline. A urea solution is input into the pre-mixing unit through the urea solution inlet pipeline, compressed air is introduced into the pre-mixing unit through the compressed air inlet pipeline, the pre-mixing unit is used for fully mixing the compressed air and the urea solution, and the mixed urea solution is conveyed to the fine gap slope atomization spraying component through the gas-liquid mixing pipeline. The fine gap slope atomization spraying component has higher adaptability to impurity particles in water and can generate finer and more uniform atomization particles, so that complete evaporation of a urea mixed solution is facilitated, and the atomization efficiency is improved. The gas-liquid mixing pipeline is sleeved with a cooling air pipeline used for isolating high-temperature flue gas.

Description

Technical Field

[0001] The present invention belongs to the technical field of spray guns, and relates to a two-fluid mixing spray gun and a using method thereof. Background Art

[0002] The SCR reductants for flue gas denitrification in gas turbine-steam cycle units are basically concentrated in liquid ammonia or ammonia water. Its process is simple, with low initial investment and operating costs and a stable system. However, since liquid ammonia or ammonia water is a toxic and dangerous chemical, and the storage volume of liquid ammonia or ammonia water in gas turbine power plants is large, major hazard sources have been formed, and the safety risk is high. Due to the safety risk of liquid ammonia, the SCR denitrification technology using urea to prepare reductants has been widely applied. Its reductant preparation technologies mainly include urea pyrolysis, urea direct injection, and urea hydrolysis. Urea pyrolysis often uses high-temperature flue gas at the outlet of a gas turbine, which is led out through a high-temperature fan and introduced into a urea pyrolysis furnace to pyrolyze urea solution to produce ammonia. The urea hydrolysis system uses low-quality steam (0.8 - 1.0, 160 - 200 °C) to cause the urea solution in the reactor to undergo a hydrolysis reaction to produce a mixed gas containing ammonia. The system is complex, and the auxiliary pipelines have high requirements for heat preservation and heat tracing, and are prone to pipeline crystallization blockage and valve corrosion. Both of the above ammonia production technologies require a large amount of heat sources, and the system operation and maintenance costs are high, which to a certain extent restricts their engineering applications. The urea direct injection pyrolysis technology is to atomize urea solution and spray it into the flue duct, and use the high-temperature flue gas (350 - 600 °C) in the flue duct to pyrolyze the urea solution to generate a mixed gas containing ammonia for use in the downstream SCR reactor. The system is simple and the operation is convenient.

[0003] In the traditional two-fluid urea spray gun of the urea direct injection pyrolysis process, urea solution and atomizing air are mixed and atomized at the nozzle and then sprayed into the flue duct. This spray gun has the following defects: 1. The concentration of nitrogen oxides at the denitrification inlet of the waste heat boiler system of the gas turbine unit is low, the ammonia consumption is small, the flow rate is small, and the concentration of the less urea solution flows in the spray gun pipeline and is easily evaporated dry under the action of high-temperature flue gas; 2. The urea direct injection pyrolysis spray gun is arranged in a mesh shape in the flue duct, and the insertion depth is relatively deep. If there are impurities in the urea solution, the impurities will accumulate and block the pipeline and nozzle in the spray rod during long-term operation, seriously affecting the operation safety.

[0004] In summary, the urea solution in the existing spray gun is easily evaporated dry under the action of high-temperature flue gas, and the pipeline and nozzle in the spray rod are easily blocked. Summary of the Invention

[0005] The object of the present invention is to provide a two-fluid mixing spray gun and its use method, so as to solve the technical problems that the urea solution in the existing spray gun is easily evaporated and dried under the action of high-temperature flue gas, and the pipelines and nozzles in the spray rod are easily blocked. The present invention can realize the full mixing of the urea solution and the atomizing air, improve the effect of direct injection and pyrolysis of urea, and can avoid the evaporation and drying of the urea solution in the spray gun under the action of high-temperature flue gas, and avoid the blockage of the pipelines and nozzles in the spray rod.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention discloses a two-fluid mixing spray gun, which includes a gas-liquid mixing pipeline. The inlet of the gas-liquid mixing pipeline is respectively connected to a compressed air inlet pipeline and a urea solution inlet pipeline through a pre-mixing unit. A filtering unit is provided on the urea solution inlet pipeline. The outlet of the gas-liquid mixing pipeline is connected to a fine-gap slope atomizing spraying component, and a cooling air pipeline is sleeved on the gas-liquid mixing pipeline.

[0007] Further, the pre-mixing unit is connected to the gas-liquid mixing pipeline through a mixing unit, and the pre-mixing unit, the mixing unit and the gas-liquid mixing pipeline are all detachably and fixedly connected.

[0008] Further, the compressed air inlet pipeline, the mixing unit, the gas-liquid mixing pipeline and the pre-mixing unit are all coaxially arranged.

[0009] Further, a porous spraying component is provided on the pre-mixing unit, and the porous spraying component is located between the urea solution inlet pipeline and the compressed air inlet pipeline.

[0010] Further, the urea solution inlet pipeline includes a first inlet pipeline and a second inlet pipeline. A filtering unit is provided between the first inlet pipeline and the second inlet pipeline, and the second inlet pipeline is connected to the pre-mixing unit.

[0011] Further, the filtering unit is detachably and fixedly connected to both the first inlet pipeline and the second inlet pipeline.

[0012] Further, an outer sleeve is sleeved on the cooling air pipeline.

[0013] Further, a cooling air inlet pipeline is provided on the cooling air pipeline, and the cooling air inlet pipeline is internally communicated with the cooling air pipeline.

[0014] Further, the gas-liquid mixing pipeline is of an L-shaped structure, the inlet direction of the gas-liquid mixing pipeline is perpendicular to the outlet direction, and the spraying angle of the fine-gap slope atomizing spraying component is 90 degrees.

[0015] Based on the above structure, the present invention also discloses a use method of the two-fluid mixing spray gun. Using the two-fluid mixing spray gun, the specific steps are as follows: Compressed air is introduced into the premixing unit through the compressed air inlet pipe. The urea solution is filtered by the filtering unit and then input into the premixing unit through the urea solution inlet pipe. The compressed air and the urea solution are mixed in the premixing unit and then input into the gas-liquid mixing pipe, and finally sprayed out through the fine-gap slope atomizing spraying component; Meanwhile, cooling air is introduced into the cooling air pipe, and the heat of the high-temperature flue gas is shielded by the cooling air. The cooling air is finally discharged into the flue.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present invention, the filtering unit filters solid particles such as impurities and undissolved urea in the urea solution, avoiding the blockage of the pipelines and nozzles in the gas-liquid mixing pipe by the solid particles. The urea solution is input into the premixing unit through the urea solution inlet pipe, and compressed air is introduced into the premixing unit through the compressed air inlet pipe. The premixing unit is used to fully mix the compressed air and the urea solution. The mixed urea solution is transported to the fine-gap slope atomizing spraying component through the gas-liquid mixing pipe. The fine-gap slope atomizing spraying component has a larger spray hole design, has greater adaptability to impurity particles in water, and is not easily blocked. Moreover, the fine-gap slope atomizing spraying component can generate finer and more uniform atomized particles, which is beneficial to the complete evaporation of the urea mixed solution and improves the atomization efficiency. A cooling air pipe is sleeved on the gas-liquid mixing pipe to isolate the high-temperature flue gas and prevent the urea mixed solution inside the gas-liquid mixing pipe from being evaporated dry by the high temperature, affecting the urea direct injection effect.

[0017] 2. Between the premixing unit, the mixing unit and the gas-liquid mixing pipe of the present invention, and between the filtering unit and the urea solution inlet pipe, they are all connected in a detachable and fixed connection form, which is convenient for disassembly, installation and maintenance.

[0018] 3. The premixing unit of the present invention is provided with a porous spraying component, which is located between the urea solution inlet pipe and the compressed air inlet pipe. The porous spraying component is beneficial to the atomized air to form a high-speed rotating air flow, and the high-speed rotating air flow drives the rapid mixing of the urea solution, facilitating the full mixing of the urea solution and the atomized air.

[0019] 4. By arranging a mixing unit between the premixing unit and the gas-liquid mixing pipe, the present invention further improves the mixing degree of the urea solution and the mixed air.

[0020] 5. The method of the present invention introduces compressed air into the premixing unit through the compressed air inlet pipe, filters the urea solution through the filtering unit and then inputs it into the premixing unit through the urea solution inlet pipe. The compressed air and the urea solution are mixed in the premixing unit and then input into the gas-liquid mixing pipe, and finally sprayed out through the fine-gap slope atomizing spraying component. The fine-gap slope atomizing spraying component has a large spray hole design, has greater adaptability to impurity particles in water, and is not easily blocked. Moreover, the fine-gap slope atomizing spraying component can generate finer and more uniform atomized particles, which is beneficial to the complete evaporation of the urea mixed solution and improves the atomization efficiency. At the same time, cooling air is introduced into the cooling air pipe to shield the heat of the high-temperature flue gas evaporation through the cooling air, avoiding the urea mixed solution inside the gas-liquid mixing pipe from being dried by high temperature and affecting the urea direct injection effect. The cooling air is finally discharged into the flue. Brief Description of the Drawings

[0021] Figure 1 is a schematic diagram of the urea gun structure of the urea direct injection and pyrolysis process of the present invention; Figure 2 is a schematic diagram of the porous injection structure of the atomizing air inlet section of the present invention; Figure 3 is a structural diagram of the fine-gap slope atomizing spraying component of the present invention; Figure 4 is a flowchart of the method of the present invention.

[0022] Wherein: 1. Compressed air inlet pipe; 2. Porous injection component; 3. Urea solution inlet pipe; 4. Cooling air inlet pipe; 5. Mixing unit; 6. Cooling air pipe; 7. Gas-liquid mixing pipe; 8. Premixing unit; 9. Fine-gap slope atomizing spraying component; 10. Outer sleeve pipe; 11. Filtering unit. Detailed Embodiments

[0023] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] It should be noted that the terms "first", "second", etc. in the description, claims and the above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0025] The present invention will be further described in detail below with reference to the accompanying drawings: See Figure 1 , the present invention discloses a two-fluid mixing spray gun, which includes a gas-liquid mixing pipeline 7. The gas-liquid mixing pipeline 7 is used to transport the uniformly mixed urea solution and compressed air to the fine-gap slope atomization spraying component 9. At the inlet of the gas-liquid mixing pipeline 7, a pre-mixing unit 8 is respectively connected to a compressed air inlet pipeline 1 and a urea solution inlet pipeline 3. The compressed air inlet pipeline 1 is used to introduce compressed air into the pre-mixing unit 8, and the urea solution inlet pipeline 3 is used to input urea solution into the pre-mixing unit 8. The pre-mixing unit 8 is used to fully mix the compressed air and the urea solution. A filtering unit 11 is provided on the urea solution inlet pipeline 3. The filtering unit 11 is used to filter out solid particles such as impurities and undissolved urea in the urea solution to prevent the solid particles from blocking the inner pipeline and nozzle of the gas-liquid mixing pipeline. The outlet of the gas-liquid mixing pipeline 7 is connected to the fine-gap slope atomization spraying component 9. See Figure 3 , the fine-gap slope atomization spraying component 9 has a larger spray hole design, has greater adaptability to impurities and particles in water, and is not easily blocked. In contrast, the inner diameter of a common nozzle is very small and is easily blocked by substances such as particulate matter and impurities, affecting the use effect. Moreover, the fine-gap slope atomization spraying component 9 can generate finer and more uniform atomized particles, which is beneficial to the complete evaporation of the urea mixed solution and improves the atomization efficiency. In contrast, the spraying effect of a common nozzle is poor, the sprayed urea mixed solution is not fine enough, and dripping problems are likely to occur. After the dripping urea mixed solution dries up, it is easy to block the nozzle. A cooling air pipeline 6 is sleeved on the gas-liquid mixing pipeline 7 to isolate high-temperature flue gas and prevent the urea mixed solution inside the gas-liquid mixing pipeline 7 from being evaporated by high temperature, affecting the direct injection effect of urea. To sum up, the present invention can achieve the full mixing of the urea solution and atomized air, improve the effect of direct injection and pyrolysis of urea, and can prevent the urea solution in the spray gun from being easily evaporated under the action of high-temperature flue gas and prevent the pipeline and nozzle in the spray rod from being blocked.

[0026] See Figure 1, in another feasible embodiment of the present invention, the following is adaptively modified according to the situation. It includes a gas-liquid mixing pipeline 7. The inlet of the gas-liquid mixing pipeline 7 is respectively connected to a compressed air inlet pipeline 1 and a urea solution inlet pipeline 3 through a premixing unit 8. A filtering unit 11 is provided on the urea solution inlet pipeline 3. The outlet of the gas-liquid mixing pipeline 7 is connected to a fine-slit slope atomizing spraying component 9. A cooling air pipeline 6 is sleeved on the gas-liquid mixing pipeline 7.

[0027] During specific operation, urea solution is input into the premixing unit 8 through the urea solution inlet pipeline 3. During this period, the filtering unit 11 is used to filter out impurities and solid particles such as undissolved urea in the urea solution. Compressed air is introduced into the premixing unit 8 through the compressed air inlet pipeline 1. The compressed air and the urea solution are fully mixed by the premixing unit 8. The mixed urea solution is transported to the fine-slit slope atomizing spraying component 9 through the gas-liquid mixing pipeline 7. During this period, cooling air is introduced into the cooling air pipeline 6 to isolate high-temperature flue gas and prevent the urea mixed solution inside the gas-liquid mixing pipeline 7 from being evaporated dry by high temperature, which affects the effect of direct urea injection.

[0028] Embodiment 1: See Figure 1 , this embodiment discloses a two-fluid mixing spray gun, which includes a gas-liquid mixing pipeline 7. The inlet of the gas-liquid mixing pipeline 7 is respectively connected to a compressed air inlet pipeline 1 and a urea solution inlet pipeline 3 through a premixing unit 8. A filtering unit 11 is provided on the urea solution inlet pipeline 3. The outlet of the gas-liquid mixing pipeline 7 is connected to a fine-slit slope atomizing spraying component 9. A cooling air pipeline 6 is sleeved on the gas-liquid mixing pipeline 7.

[0029] Preferably, the premixing unit 8 is connected to the gas-liquid mixing pipeline 7 through a mixing unit 5. The connections between the premixing unit 8, the mixing unit 5 and the gas-liquid mixing pipeline 7 are all detachable and fixed connections.

[0030] By arranging a mixing unit 5 between the premixing unit 8 and the gas-liquid mixing pipeline 7, the mixing degree of the urea solution and the mixed air is further improved.

[0031] The detachable and fixed connection is specifically that the connections between the premixing unit 8, the mixing unit 5 and the gas-liquid mixing pipeline 7 are all through threaded connections, which is convenient for disassembly and maintenance. After long-term use, solid impurities and solid urea deposits may remain inside the premixing unit 8, the mixing unit 5 and the gas-liquid mixing pipeline 7. Through the form of detachable and fixed connection, the premixing unit 8, the mixing unit 5 and the gas-liquid mixing pipeline 7 can be regularly disassembled for cleaning and maintenance to avoid blockage of the gas-liquid mixing pipeline 7 and the fine-slit slope atomizing spraying component 9 caused by solid impurities and solid urea deposits.

[0032] Preferably, the compressed air inlet pipe 1, the mixing unit 5, the gas-liquid mixing pipe 7, and the premixing unit 8 are coaxially arranged.

[0033] Preferably, a porous injection component 2 is provided on the premixing unit 8. Refer to Figure 2 , and the porous injection component 2 is located between the urea solution inlet pipe 3 and the compressed air inlet pipe 1. The porous injection component 2 is beneficial to atomizing the air to form a high-speed rotating air flow, and the high-speed rotating air flow drives the urea solution to be quickly mixed, facilitating the full mixing of the urea solution and the atomized air.

[0034] Embodiment 2: Refer to Figure 1 , this embodiment discloses a two-fluid mixing spray gun, which includes a gas-liquid mixing pipe 7. The inlet of the gas-liquid mixing pipe 7 is respectively connected to a compressed air inlet pipe 1 and a urea solution inlet pipe 3 through a premixing unit 8. A filtering unit 11 is provided on the urea solution inlet pipe 3. The outlet of the gas-liquid mixing pipe 7 is connected to a fine-gap slope atomizing injection component 9, and a cooling air pipe 6 is sleeved on the gas-liquid mixing pipe 7.

[0035] Preferably, the urea solution inlet pipe 3 includes a first inlet pipe and a second inlet pipe. A filtering unit 11 is provided between the first inlet pipe and the second inlet pipe, and the second inlet pipe is connected to the premixing unit 8.

[0036] Preferably, the filtering unit 11 is detachably and fixedly connected to both the first inlet pipe and the second inlet pipe.

[0037] Preferably, the filtering unit 11 is connected to the first inlet pipe and the second inlet pipe by threads.

[0038] The connection form of the filtering unit 11 with the first inlet pipe and the second inlet pipe is a detachable fixed connection, which is beneficial to the disassembly, installation and maintenance of the filtering unit 11, and facilitates the regular removal of the filtering unit 11 for cleaning. The setting of the filtering unit 11 is beneficial to removing solid particles in the urea solution and avoiding the blockage of the gas-liquid mixing pipe 7 and the fine-gap slope atomizing injection component 9 by solid particles.

[0039] Embodiment 3: Refer to Figure 1 , this embodiment discloses a two-fluid mixing spray gun, which includes a gas-liquid mixing pipe 7. The inlet of the gas-liquid mixing pipe 7 is respectively connected to a compressed air inlet pipe 1 and a urea solution inlet pipe 3 through a premixing unit 8. A filtering unit 11 is provided on the urea solution inlet pipe 3. The outlet of the gas-liquid mixing pipe 7 is connected to a fine-gap slope atomizing injection component 9, and a cooling air pipe 6 is sleeved on the gas-liquid mixing pipe 7.

[0040] Preferably, the cooling air duct 6 is provided with an outer sleeve 10 to further enhance the heat insulation capability and prevent the mixed solution inside the gas-liquid mixing duct 7 from being evaporated.

[0041] Preferably, a cooling air inlet duct 4 is provided on the cooling air duct 6 , and the cooling air inlet duct 4 is communicated with the interior of the cooling air duct 6 .

[0042] Preferably, the gas-liquid mixing pipeline 7 is an L-shaped structure, the inlet direction of the gas-liquid mixing pipeline 7 is perpendicular to the outlet direction, and the spray angle of the fine gap slope atomization spray component 9 is 90 degrees.

[0043] Embodiment 4: See also Figure 1 The present embodiment discloses a dual-fluid mixing spray gun, comprising a compressed air inlet pipe 1, a porous injection component 2, a urea solution inlet pipe 3, a cooling air inlet pipe 4, a mixing unit 5, a cooling air pipe 6, a gas-liquid mixing pipe 7, a premixing unit 8, a fine-gap slope atomizing injection component 9 and an outer sleeve 10.

[0044] The purpose of the present invention is to overcome the deficiencies of the prior art, solve the problems of urea solution in the existing spray gun being evaporated and blocked under the action of high-temperature flue gas, and the difficulty in manufacturing and repairing the spray gun, and provide a spray gun mixing structure for a urea direct injection pyrolysis system, in which atomizing air and urea solution are premixed at the front end of the spray gun, the gas-liquid mixture is fully mixed in the spray gun spray rod and flows at a high speed, and is atomized and sprayed into the flue near the nozzle. The spray gun can effectively reduce the high-temperature evaporation and blockage problems of the pipeline in the urea solution spray gun through reasonable design, reduce the difficulty in repairing the spray gun, make the spray gun simpler and more convenient, and at the same time, use cooling wind to take away part of the heat to ensure the atomization effect of the gas-liquid mixture at the fine gap slope atomization injection component 9.

[0045] In order to achieve the above-mentioned purpose, the present invention includes a gun rod and a fine-gap slope atomizing injection component 9, wherein the gun rod includes a cooling air duct 6, a compressed air inlet duct 1, a urea solution inlet duct 3 and a urea solution gas-liquid mixing duct 7, a premixing unit 8 and a mixing unit 5; the gas-liquid mixing duct 7 and the cooling air duct 6 are sequentially distributed from the inside to the outside, a cooling air inlet duct 4 is provided on the side of one end of the cooling air duct 6, a compressed air inlet duct 1 and a urea solution inlet duct 3 are provided on the side of one end of the premixing unit 8, and the fine-gap slope atomizing injection component 9 is connected to the other end of the gas-liquid mixing duct 7. The atomizing air inlet cross section of the premixing unit 8 adopts a multi-hole injection component 2, see Figure 2 , the fine gap slope atomizing spray component 9 adopts a fine gap slope structure, see Figure 3。An outer sleeve 10 is provided on the outer wall of the cooling air. The direction towards which the fine-gap slope atomizing injection component 9 faces is perpendicular to the axis of the gas-liquid mixing pipe 7. The urea solution enters the side inlet of the premixing unit 8 at a certain pressure and flow rate, and the atomizing air enters the front inlet of the premixing unit 8 at a certain pressure and flow rate. In the premixing unit 8, the atomizing air at a higher pressure passes through the porous injection component 2, and the high-speed rotating air flow drives the urea solution to mix rapidly and enter the mixing unit 5. Under the action of the mixing unit 5, the urea solution is further mixed in the air flow and is atomized at a 90-degree angle and sprayed into the flue through the fine-gap slope structure of the fine-gap slope atomizing injection component 9. The cooling air enters between the cooling air pipe 6 and the gas-liquid mixing pipe 7 and is finally sprayed into the flue. When the flue gas gun is operating, the high-temperature flue gas first scours the outer sleeve 10 on the outside, and part of the heat is carried away by the cooling air. The atomizing air drives the urea solution to quickly enter the spraying device through the spray rod, avoiding the urea solution from being evaporated dry by the high-temperature flue gas and ensuring the atomization effect of the urea solution sprayed by the atomizing injection component.

[0046] Based on the above structure, the present invention also discloses a method for using a two-fluid mixing spray gun. Refer to Figure 4 , and adopt a two-fluid mixing spray gun. The specific steps are as follows: S1. Compressed air is introduced into the premixing unit 8 through the compressed air inlet pipe 1, and the urea solution is filtered through the filtering unit 11 and then input into the premixing unit 8 through the urea solution inlet pipe 3. The compressed air and the urea solution are mixed in the premixing unit 8 and then input into the gas-liquid mixing pipe 7, and finally sprayed out through the fine-gap slope atomizing injection component 9. The fine-gap slope atomizing injection component 9 has a larger spray hole design, has greater adaptability to impurity particles in water, and is not easily blocked. Moreover, the fine-gap slope atomizing injection component 9 can generate finer and more uniform atomized particles, which is beneficial to the complete evaporation of the urea mixed solution and improves the atomization efficiency; S2. At the same time, cooling air is introduced into the cooling air pipe 6, and the heat of the high-temperature flue gas is shielded by the cooling air to prevent the urea mixed solution inside the gas-liquid mixing pipe 7 from being evaporated dry by the high temperature, which affects the direct injection effect of urea. The cooling air is finally discharged into the flue.

[0047] The present invention can achieve the full mixing of the urea solution and the atomizing air, improve the effect of direct injection and pyrolysis of urea, and can avoid the urea solution in the spray gun from being easily evaporated dry under the action of high-temperature flue gas and avoid the blockage of the pipes and nozzles inside the spray rod.

[0048] Embodiment 4: Refer to Figure 1 , this embodiment discloses a method for using a two-fluid mixing spray gun. Refer to Figure 4 , and the specific steps are as follows: S1. Compressed air is introduced into the premixing unit 8 through the compressed air inlet pipe 1, and the urea solution is filtered through the filtering unit 11 and then input into the premixing unit 8 through the urea solution inlet pipe 3. The compressed air and the urea solution are preliminarily mixed in the premixing unit 8; S2. The urea solution inside the premixing unit 8 enters the mixing unit 5 for secondary mixing, which is beneficial to improving the mixing degree of the urea solution and the atomizing air; S3. The uniformly mixed urea solution enters the gas-liquid mixing pipe 7. At the same time, cooling air is introduced into the cooling air pipe 6. The heat of the high-temperature flue gas evaporation is shielded by the cooling air to prevent the urea mixed solution inside the gas-liquid mixing pipe 7 from being dried by the high temperature, which affects the urea direct injection effect. The cooling air finally discharges into the flue; S4. The mixed urea solution is sprayed out through the fine-gap slope atomizing spraying component 9. The fine-gap slope atomizing spraying component 9 has a relatively large spray hole design, has greater adaptability to impurity particles in water, and is not easily blocked. Moreover, the fine-gap slope atomizing spraying component 9 can generate finer and more uniform atomized particles, which is beneficial to the complete evaporation of the urea mixed solution and improves the atomizing efficiency.

[0049] The above content is only to illustrate the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A dual-fluid mixing spray gun, characterized in that: The invention comprises a gas-liquid mixing pipeline (7), wherein the inlet of the gas-liquid mixing pipeline (7) is respectively connected to a compressed air inlet pipeline (1) and a urea solution inlet pipeline (3) via a premixing unit (8), the urea solution inlet pipeline (3) is provided with a filtering unit (11), the outlet of the gas-liquid mixing pipeline (7) is connected to a fine-gap slope atomizing injection component (9), and a cooling air pipeline (6) is sleeved on the gas-liquid mixing pipeline (7).

2. A two-fluid mixing spray gun according to claim 1, characterized in that: The premixing unit (8) is connected to the gas-liquid mixing pipeline (7) via the mixing unit (5), and the premixing unit (8), the mixing unit (5) and the gas-liquid mixing pipeline (7) are all detachably fixedly connected.

3. A two-fluid mixing spray gun according to claim 2, characterized in that: The compressed air inlet pipeline (1), the mixing unit (5), the gas-liquid mixing pipeline (7) and the pre-mixing unit (8) are all coaxially arranged.

4. A two-fluid mixing spray gun according to claim 1, characterized in that: The premixing unit (8) is provided with a multi-hole injection component (2), and the multi-hole injection component (2) is located between the urea solution inlet pipe (3) and the compressed air inlet pipe (1).

5. A two-fluid mixing spray gun according to claim 1, characterized in that: The urea solution inlet pipe (3) comprises a first inlet pipe and a second inlet pipe, a filtering unit (11) is provided between the first inlet pipe and the second inlet pipe, and the second inlet pipe is connected to the premixing unit (8).

6. A two-fluid mixing spray gun according to claim 5, characterized in that: The filter unit (11) is detachably fixedly connected to the first inlet pipe and the second inlet pipe.

7. A two-fluid mixing spray gun according to claim 1, characterized in that: The cooling air duct (6) is sleeved with an outer sleeve (10).

8. A two-fluid mixing spray gun according to claim 1 or 7, characterized in that: The cooling air duct (6) is provided with a cooling air inlet duct (4), and the cooling air inlet duct (4) is in communication with the interior of the cooling air duct (6).

9. A two-fluid mixing spray gun according to claim 1, characterized in that: The gas-liquid mixing pipeline (7) is of an L-shaped structure; the inlet direction of the gas-liquid mixing pipeline (7) is perpendicular to the outlet direction; and the spray angle of the fine-slit slope atomizing spray component (9) is 90 degrees.

10. A method for using a dual-fluid mixing spray gun, characterized in that: Using the dual-fluid mixing spray gun described in any one of claims 1 to 9, the specific steps are as follows: Compressed air is introduced into the premixing unit (8) through the compressed air inlet pipe (1), the urea solution is filtered through the filtering unit (11) and then input into the premixing unit (8) through the urea solution inlet pipe (3), the compressed air and the urea solution are mixed in the premixing unit (8) and then input into the gas-liquid mixing pipe (7), and finally sprayed out through the fine gap slope atomization spray component (9); At the same time, cooling air is introduced into the cooling air duct (6), and the heat of the high-temperature flue gas is shielded by the cooling air. The cooling air is finally discharged into the flue.

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