A two-fluid urea direct injection lance structure

Abstract

The utility model provides a kind of double fluid urea straight spray spray gun structure, belong to spray gun technical field. Including gun rod, the bottom of gun rod is fixed with urea solution connector, and the bottom outside of gun rod is fixed with atomization air connector;The cooling air pipe is spiral structure, and its spiral channel is around the outer wall of gun rod, the gas inlet end of cooling air pipe is located at the side of gun rod bottom, and the gas outlet end of cooling air pipe extends to the top of gun rod;The spraying mechanism is installed at the top of gun rod, for spraying the urea solution of mixed atomization air. The contact area of cooling air and gun rod is increased compared with traditional straight pipe type by spiral cooling air pipe, which greatly prolongs the flow path of cooling air, solves the problem of uneven distribution of traditional single channel cooling air and limited heat exchange area.

Description

Technical Field

[0001] This utility model relates to the field of spray gun technology, and in particular to a dual-fluid urea direct injection spray gun structure. Background Technology

[0002] In the flue-type urea direct injection pyrolysis process used for gas turbine denitrification, the cooling air duct of the dual-fluid urea direct injection nozzle plays a crucial role in heat dissipation, and its cooling efficiency directly affects the stable operation of the entire denitrification system.

[0003] According to publication number CN106955593A, a dual-fluid urea direct injection spray gun structure suitable for gas turbine denitrification flue gas urea direct injection pyrolysis process is disclosed, including a gun rod and an atomizing nozzle. The gun rod includes a cooling air duct, an atomizing air duct, and a urea solution duct. The urea solution duct, the atomizing air duct, and the cooling air duct are distributed sequentially from the inside to the outside. A cooling air inlet is provided on the side of one end of the cooling air duct, and an atomizing air inlet is provided on the side of one end of the atomizing air duct. The atomizing nozzle is fixed to the side of the other end of the cooling air duct. The atomizing air inlet of the atomizing nozzle is connected to the other end of the atomizing air duct. The urea solution inlet of the atomizing nozzle is connected to the urea solution duct. An insulation layer is provided on the outer wall of the cooling air duct, wherein the insulation layer is located inside the flue gas duct.

[0004] Currently, the cooling air ducts of dual-fluid urea direct injection nozzles used in gas turbine denitrification mostly employ a single-channel design. This results in a short and uneven flow path for the cooling air within the duct, limiting the heat exchange area with the atomizing air and urea solution ducts. Because the dual-fluid urea direct injection nozzles for gas turbine denitrification are inserted deep into the flue (typically 1-3 meters), the continuous heat radiation from the high-temperature flue gas (300-700°C) emitted by the gas turbine causes a rapid increase in the temperature of the duct's outer wall. The cooling air absorbs a significant amount of heat before reaching the end of the duct, leading to a substantial decrease in heat dissipation capacity in critical areas near the nozzle. Simultaneously, the temperature difference between the cooling air and the high-temperature flue gas gradually decreases as the airflow advances, significantly reducing the heat absorption efficiency of the terminal cooling air. This fails to effectively counteract the heat transfer from the flue gas to the urea solution duct, thus affecting the formation of the reducing agent in the gas turbine denitrification reaction.

[0005] Therefore, this application provides a dual-fluid urea direct injection spray gun structure to meet the requirements. Utility Model Content

[0006] The technical problem to be solved by this utility model is to provide a dual-fluid urea direct injection spray gun structure, which can prevent the problem that the cooling air duct adopts a single channel design, resulting in a short and uneven flow path of the cooling air in the duct and a limited heat exchange area with the atomizing air duct and the urea solution duct.

[0007] To solve the above-mentioned technical problems, this utility model provides the following technical solution: A dual-fluid urea direct injection gun structure includes a gun barrel, a urea solution connector fixed to the bottom of the gun barrel, and an atomizing air connector fixed to the outer side of the bottom of the gun barrel. The cooling duct has a spiral structure, with its spiral channel surrounding the outer wall of the gun barrel. The air inlet of the cooling duct is located on the bottom side of the gun barrel, and the air outlet of the cooling duct extends to the top of the gun barrel. A spraying mechanism, mounted on the top of the gun barrel, is used to spray a urea solution mixed with atomized air.

[0008] Optionally, an insulating sleeve is provided around the gun barrel and the cooling duct. The inner wall of the insulating sleeve is tightly fitted with the outer wall of the cooling duct, and the length of the insulating sleeve covers the part of the gun barrel located inside the flue. The heat insulation effect of the insulating sleeve can stably control the temperature of the outer wall of the cooling duct below 150°C, ensuring that the urea solution does not deteriorate due to high temperature during long-distance transportation.

[0009] Optionally, an annular exhaust ring is fixedly connected to the top of the cooling duct. The inner side of the exhaust ring is sealed to the outer wall of the gun barrel, and the exhaust ring has multiple downward-sloping exhaust holes to form an annular airflow barrier at the top of the gun barrel. This not only prevents high-temperature flue gas from directly scouring the spraying mechanism, but also helps the atomized urea solution mix with the flue gas.

[0010] Optionally, a top ring is fixed to the top of the gun barrel, and a connecting pipe and a leak-proof ring are fixed to the top of the top ring. The outer diameter of the leak-proof ring is larger than the outer diameter of the connecting pipe, and the spraying mechanism is rotatably mounted on the top via a bearing.

[0011] Optionally, the spraying mechanism includes a rotating column, with the connecting pipe and anti-leak ring movably installed inside the rotating column. Multiple atomizing nozzles are arranged in a ring array on the outer side of the rotating column. The outer ring of the bearing is fixed to the top of the top ring, and the inner ring of the bearing is fixed to the bottom of the rotating column. All atomizing nozzles are installed at an angle, and the spray direction of each nozzle forms an angle of 15°-45° with the radial direction of the rotating column. Urea solution and atomizing air are respectively introduced into the multiple atomizing nozzles, which are arranged in a ring array with their spray direction forming an angle with the radial direction of the rotating column. During operation, the reaction force drives the rotating column to rotate at a speed of 10-15 r / min, achieving 360° uniform spraying of the urea solution.

[0012] Optionally, a protective mechanism is installed on the outside of the spraying mechanism. The protective mechanism includes an upper connecting plate and a lower connecting plate. The lower connecting plate is fixed to the outside of the connecting pipe by bolts. The upper connecting plate and the lower connecting plate are connected by multiple protective railings arranged in a ring. The protective railings are welded between the upper connecting plate and the lower connecting plate to form a cylindrical protective net with a height exceeding the top of the atomizing nozzle to prevent fly ash in the flue from impacting and damaging the nozzle.

[0013] Compared with the prior art, this utility model has at least the following beneficial effects: The spiral cooling duct increases the contact area between the cooling air and the spray gun compared to the traditional straight duct, significantly extending the airflow path and solving the problems of uneven air distribution and limited heat exchange area in traditional single-channel cooling systems. Simultaneously, the cooling air, after being ejected through the inclined exhaust holes of the exhaust ring, forms a ring-shaped airflow barrier, enhancing heat dissipation in critical end areas and preventing direct baking of the spraying mechanism by high-temperature flue gas. This effectively compensates for the reduced heat absorption efficiency at the end of the cooling airflow in traditional structures. Combined with the insulation sleeve, the ambient temperature of the cooling duct's outer wall is controlled below 150℃, ensuring effective cooling throughout the entire spray gun.

[0014] In terms of spraying effect, the rotary atomizing nozzle achieves rotation by using reaction force, and combined with the spray angle of the ring array distribution, it achieves 360° all-round uniform spraying of urea solution, which improves the mixing efficiency with flue gas; while the airflow ejected from the exhaust ring can further assist the atomized urea solution to mix with flue gas quickly, which is conducive to the full generation of reducing agent in the gas turbine denitrification reaction. Attached Figure Description

[0015] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments of the present invention and, together with the specification, further serve to explain the principles of the present invention and enable those skilled in the art to implement and use the present invention.

[0016] Figure 1 A three-dimensional structural diagram of a dual-fluid urea direct injection spray gun. Figure 2 This is a schematic diagram of the internal structure of a dual-fluid urea direct injection spray gun. Figure 3 A schematic diagram of the cooling duct structure for a dual-fluid urea direct injection spray gun; Figure 4 A schematic diagram of the spraying mechanism for a dual-fluid urea direct injection spray gun; Figure 5 A schematic diagram of the protective mechanism of a dual-fluid urea direct injection spray gun. Figure 6 This is a schematic diagram showing the flow direction of urea solution in the mixed atomized air of a two-fluid urea direct injection spray gun structure.

[0017] [Figure Labels] 1. Gun barrel; 11. Urea solution connector; 12. Atomizing air connector; 2. Cooling duct; 21. Exhaust ring; 22. Exhaust port; 3. Spraying mechanism; 31. Rotating column; 32. Atomizing nozzle; 4. Insulation sleeve; 5. Protective mechanism; 51. Upper connecting plate; 52. Lower connecting plate; 53. Guardrail; 6. Connecting pipe; 7. Anti-leakage ring; 8. Bearing; 9. Top ring.

[0018] As shown in the figure, specific structures and devices are marked in the figure to clearly illustrate the structure of the embodiment of this utility model. However, this is only for illustrative purposes and is not intended to limit this utility model to this specific structure, device and environment. Those skilled in the art can adjust or modify these devices and environments according to specific needs. Detailed Implementation

[0019] The following is a detailed description of the dual-fluid urea direct injection spray gun structure provided by this utility model, in conjunction with the accompanying drawings and specific embodiments. It should be noted that, to make the embodiments more detailed, the following embodiments are the best and preferred embodiments; for some known technologies, those skilled in the art can also use other alternative methods to implement the invention. Furthermore, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit this utility model.

[0020] It should be noted that the use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.

[0021] Generally, terms can be understood at least partly from their use in context. For example, depending at least partly on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood not necessarily to convey an exclusive set of factors, but rather, alternatively, depending at least partly on the context, to allow for the presence of other factors that are not necessarily explicitly described.

[0022] It is understood that the meanings of “on”, “above”, and “above” in this utility model should be interpreted in the broadest manner, such that “on” not only means “directly on” something, but also includes the meaning of being “on” something with an intervening feature or layer, and that “above” or “above” not only means “on” something, but also includes the meaning of being “on” something without an intervening feature or layer.

[0023] Furthermore, spatially related terms such as “below,” “under,” “lower,” “above,” and “upper” are used herein for convenience to describe the relationship of one element or feature to one or more other elements or features, as illustrated in the accompanying drawings. Spatially related terms are intended to cover different orientations in the use or operation of the device other than those depicted in the accompanying drawings. The device may be oriented in other ways, and the spatially related descriptive terms used herein can be interpreted similarly.

[0024] The dual-fluid urea direct injection spray gun structure disclosed in this embodiment is applicable to flue-type urea direct injection pyrolysis process. Its core lies in improving cooling efficiency and atomization effect by optimizing the cooling airflow path and the coordinated design of the spraying mechanism.

[0025] like Figures 1-5 As shown, an embodiment of this utility model provides a dual-fluid urea direct injection spray gun structure, which mainly consists of a gun barrel 1, a cooling air duct 2 installed on the outside of the gun barrel 1, and a spraying mechanism 3 installed on the top of the gun barrel 1.

[0026] like Figures 1-2 As shown, the gun barrel 1 has a hollow structure and is made of 310S stainless steel to withstand high-temperature flue gas corrosion. A urea solution connector 11 is welded to the bottom of the gun barrel 1, which is threaded and sealed to the external urea solution delivery pipeline. An atomizing air connector 12 is fixed to the outside of the bottom of the gun barrel 1. The connector is a DN20 threaded interface and is connected to a compressed air source of 0.4-0.6MPa.

[0027] like Figure 2 As shown, the cooling duct 2 is made of seamless copper tubing of φ8mm×1mm bent into a spiral structure with a spiral spacing of 30mm, forming a continuous cooling channel around the outer wall of the gun barrel 1. The air inlet of the cooling duct 2 is located on the bottom side of the gun barrel 1 and is connected to the cooling air source through a connector. The air outlet of the cooling duct 2 extends to the top of the gun barrel 1 and connects to the exhaust ring 21. The spiral design maximizes the contact area between the cooling air and the gun barrel 1, improving cooling efficiency. The spiral structure increases the contact area between the cooling air and the gun barrel 1 by 2.5 times compared to the traditional straight pipe design, improving heat exchange efficiency. Figure 2 and Figure 3As shown, the exhaust ring 21 is an annular stainless steel component. The inner diameter of the exhaust ring 21 is interference-fitted with the outer wall of the gun rod 1 and sealed and fixed by argon arc welding. Multiple exhaust holes 22 are evenly distributed on the exhaust ring 21, each with a diameter of 5mm. The hole axis is inclined downwards at a 45° angle to the axis of the gun rod 1. After the cooling air is ejected through the exhaust holes 22, it forms an annular airflow barrier at the top of the gun rod 1, which not only prevents the high-temperature flue gas from directly impacting the spraying mechanism 3, but also assists in mixing the atomized urea solution with the flue gas.

[0028] like Figure 1 As shown, the gun barrel 1 and the cooling duct 2 are covered by an insulation sleeve 4. The insulation sleeve 4 has a double-layer structure, with an inner layer of 5mm thick aluminum silicate insulation cotton and an outer layer of 0.5mm thick 304 stainless steel protective shell. It is completely covered on the outside of the gun barrel 1 and the cooling duct 2. Its length is designed according to the depth of the flue (usually 1.2-3.2 meters), and both ends can be fixed with clamps to ensure complete coverage of the part of the gun barrel 1 located in the flue, so that the ambient temperature of the outer wall of the cooling duct 2 is reduced to below 150℃.

[0029] like Figure 2 , Figure 4 and Figure 6 As shown, a top ring 9 is fixed to the top of the gun barrel 1. A connecting pipe 6 and a leak-proof ring 7 are welded to the top of the top ring 9. The outer diameter of the leak-proof ring 7 is larger than the outer diameter of the connecting pipe 6, forming a stepped structure. The leak-proof ring 7 is made of polytetrafluoroethylene (PTFE). Figure 4 As shown, the spraying mechanism 3 achieves its rotation function through the bearing 8. The bearing 8 is a high-temperature resistant sealed bearing, ensuring smooth rotation while preventing fluid leakage. The outer ring of the bearing 8 is fixed to the top of the top ring 9. The spraying mechanism 3 includes a rotating column 31, and the inner ring of the bearing 8 is fixed to the bottom of the rotating column 31. The internal channel of the rotating column 31 is connected to the urea solution channel and atomizing air of the gun rod 1, as shown. Figure 6 As shown, the rotating column 31 has a flow-dividing chamber inside, and the connecting pipe 6 and the anti-leakage ring 7 are movably installed inside the rotating column 31. Multiple atomizing nozzles 32 are installed in a ring array on the outside of the rotating column 31. The flow-dividing chamber introduces the urea solution and atomizing air into the multiple atomizing nozzles 32 respectively. The atomizing nozzles 32 are distributed in a ring array, and the spray direction forms a 30° angle with the radial direction of the rotating column 31. During operation, the reaction force drives the rotating column 31 to rotate at a speed of 10-15 r / min to achieve 360° uniform spraying of the urea solution.

[0030] like Figure 1 and Figure 5As shown, a protective mechanism 5 is installed on the outside of the spraying mechanism 3. The protective mechanism 5 consists of an upper connecting plate 51, a lower connecting plate 52, and multiple protective railings 53, and is made of 201 stainless steel. The lower connecting plate 52 is fixed to the outside of the connecting pipe 6 with M8 bolts. The protective railings 53 are welded between the upper connecting plate 51 and the lower connecting plate 52 to form a cylindrical protective net, with a height exceeding the top of the atomizing nozzle 32 by 50mm to prevent fly ash in the flue from impacting and damaging the nozzle.

[0031] Working principle like Figures 1-6 As shown, urea solution enters the internal channel of the gun barrel 1 through the urea solution connector 11 at the bottom of the gun barrel 1, while compressed air at 0.4-0.6 MPa enters through the atomizing air connector 12. The two fluids are combined in the gun barrel 1 and then enter the flow-dividing chamber inside the rotating column 31 of the spraying mechanism 3. The flow-dividing chamber guides the urea solution and atomizing air into the atomizing nozzles 32 distributed in a ring array. Since the atomizing nozzles 32 and the rotating column 31 form a radial angle of 30°, the reaction force generated when the fluid is sprayed drives the rotating column 31 to rotate at a speed of 10-15 r / min. With the help of the smooth rotation of the bearing 8, the urea solution is sprayed evenly in all directions at 360°.

[0032] Meanwhile, cooling air enters the spiral channel through the bottom air inlet of cooling air duct 2. Because the cooling air duct is spiral-shaped, the contact area with the nozzle 1 is increased by 2.5 times compared to traditional structures, enabling efficient absorption of the heat absorbed by the nozzle 1 in the high-temperature flue. After rising to the top along the spiral channel, the cooling air is ejected through the 5mm diameter exhaust holes 22 at a 45° angle downwards on the exhaust ring 21, forming an annular airflow barrier around the spraying mechanism 3. This not only prevents the high-temperature flue gas from directly baking the nozzle but also assists in the rapid mixing of the atomized urea solution with the flue gas.

[0033] Furthermore, the insulation sleeve 4 outside the gun barrel 1 and the cooling air duct 2 further reduces heat conduction, keeping the ambient temperature of the outer wall of the cooling air duct 2 below 150℃.

[0034] The 201 stainless steel protective mechanism 5 on the outside of the spraying mechanism 3 effectively blocks the impact of fly ash in the flue, and multiple protections ensure stable operation of the equipment in a high-temperature and corrosive environment.

[0035] This utility model encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this utility model. To provide the public with a thorough understanding of this utility model, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand this utility model even without these detailed descriptions. Furthermore, to avoid unnecessary confusion regarding the essence of this utility model, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0036] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A dual-fluid urea direct injection spray gun structure, characterized in that, include: Gun barrel (1), the bottom of the gun barrel (1) is fixed with a urea solution connector (11), and the outer side of the bottom of the gun barrel (1) is fixed with an atomizing air connector (12). Cooling duct (2), the cooling duct (2) has a spiral structure, its spiral channel surrounds the outer wall of the gun barrel (1), the air inlet of the cooling duct (2) is located on the bottom side of the gun barrel (1), and the air outlet of the cooling duct (2) extends to the top of the gun barrel (1). Spraying mechanism (3), which is installed on the top of the gun rod (1), is used to spray out a urea solution mixed with atomized air.

2. The dual-fluid urea direct injection spray gun structure according to claim 1, characterized in that, The gun barrel (1) and the cooling air duct (2) are covered with an insulation sleeve (4). The inner wall of the insulation sleeve (4) is tightly fitted with the outer wall of the cooling air duct (2), and the length of the insulation sleeve (4) covers the part of the gun barrel (1) located in the flue.

3. The dual-fluid urea direct injection spray gun structure according to claim 1, characterized in that, The top of the cooling duct (2) is fixedly connected to an annular exhaust ring (21). The inner side of the exhaust ring (21) is sealed to the outer wall of the gun rod (1), and the exhaust ring (21) has multiple downward-sloping exhaust holes (22).

4. The dual-fluid urea direct injection spray gun structure according to claim 1, characterized in that, The top of the gun barrel (1) is fixed with a top ring (9), and the top of the top ring (9) is fixed with a connecting pipe (6) and a leak-proof ring (7). The outer diameter of the leak-proof ring (7) is larger than the outer diameter of the connecting pipe (6), and the spraying mechanism (3) is rotatably mounted on the top of the top ring (9) via a bearing (8).

5. The dual-fluid urea direct injection spray gun structure according to claim 4, characterized in that, The spraying mechanism (3) includes a rotating column (31), the connecting pipe (6) and the anti-leakage ring (7) are movably installed inside the rotating column (31), and multiple atomizing nozzles (32) are installed in a ring array on the outer side of the rotating column (31). The outer ring of the bearing (8) is fixed to the top of the top ring (9), and the inner ring of the bearing (8) is fixed to the bottom of the rotating column (31).

6. The dual-fluid urea direct injection spray gun structure according to claim 5, characterized in that, All of the atomizing nozzles (32) are installed at an angle, and the spraying direction of the atomizing nozzles (32) is at an angle of 15°-45° with the radial direction of the rotating column (31).

7. The dual-fluid urea direct injection spray gun structure according to claim 4, characterized in that, The spraying mechanism (3) is equipped with a protective mechanism (5) on its outer side. The protective mechanism (5) includes an upper connecting plate (51) and a lower connecting plate (52). The lower connecting plate (52) is fixed to the outer side of the connecting pipe (6) by bolts. The upper connecting plate (51) and the lower connecting plate (52) are connected by a plurality of protective railings (53) arranged in a ring.

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