Urea spray gun for flue gas denitration

Abstract

The utility model belongs to the technical field of flue gas denitration, and discloses a urea spray gun for flue gas denitration, which comprises a spray gun, a spray gun flange is sleeved on the spray gun, an atomizing nozzle is vertically arranged at the right lower end of the spray gun, and an inner pipe and an outer pipe of the spray gun are both connected with the atomizing nozzle; the spray gun flange is detachably connected with the sealing assembly, the left end of the sealing assembly is arranged on the outer side of a heat preservation layer of the flue, the right end of the sealing assembly is fixedly arranged in a hole formed in the heat preservation layer of the flue in a penetrating mode, and a protection air connector is vertically arranged at the upper left end of the sealing assembly and connected with protection air through a protection air connecting assembly. A spray gun at the right end of the spray gun flange penetrates through the sealing assembly and extends into the flue; according to the utility model, the atomization effect is good, a urea solution can react quickly when being in contact with flue gas, the phenomenon that part of urea falls to the bottom of the flue due to the fact that ammonia gas cannot be generated in time is avoided, hot gas in the flue can be effectively prevented from escaping from the hole for mounting the spray gun on the wall of the flue due to the design of protective air, and potential safety hazards are reduced.

Description

Technical Field

[0001] This utility model belongs to the field of flue gas denitrification technology, specifically relating to a urea spray gun for flue gas denitrification. Background Technology

[0002] Currently, the main flue gas denitrification technologies include Selective Catalytic Reduction (SCR), Selective Non-Catalytic Reduction (SNCR), and hybrid methods (SNCR+SCR). Selective Catalytic Reduction (SCR) is widely used in my country due to its high denitrification efficiency and mature technology. SCR denitrification involves the selective catalytic reduction of NOx in flue gas with ammonia at a temperature of 300–420℃, producing nitrogen and water, thereby achieving denitrification. To provide the ammonia required for the SCR denitrification system, the main reducing agents are urea, liquid ammonia, and ammonia water. Urea has become the primary reducing agent for SCR denitrification due to its advantages such as no safety requirements and ease of storage and transportation.

[0003] Urea solution, used as a denitrification reducing agent in SCR systems, primarily employs direct urea injection technology. Diluted urea solution is sprayed into the boiler's tail flue through a spray gun. Existing urea spray guns have the following drawbacks: 1. After the urea solution is sprayed into the boiler's tail flue, it comes into contact with the flue gas. The urea solution enters the flue in the form of large water droplets. Some urea can generate ammonia gas at high temperatures, while some falls to the bottom of the flue before ammonia gas can be generated. After the water evaporates, it remains at the bottom of the flue as solid urea, requiring specialized cleaning over time, thus wasting urea solution. Furthermore, it requires time for specialized cleaning, and not all urea solutions can be pyrolyzed to form ammonia, affecting boiler efficiency. Moreover, for boilers with insufficient tail space, if the urea is sprayed onto the boiler heating surface before it is fully decomposed, the urea droplets will cause corrosion and other effects on the heating surface over time. 2. When the spray gun is replaced, the hot air in the flue will escape from the holes in the flue wall where the spray gun is installed. The hot air in the flue is often 500-600℃. Although the staff takes protective measures during operation, the high temperature of the hot air still poses a great safety hazard to the staff.

[0004] Based on the above problems, a urea spray gun for flue gas denitrification is proposed. Utility Model Content

[0005] In order to solve the above-mentioned technical problems, this utility model provides a urea spray gun for flue gas denitrification, which has a simple and reasonable structure, is easy to install, and is easy to operate.

[0006] The technical solution adopted by this utility model is as follows: a urea spray gun for flue gas denitrification, comprising a spray gun, which is divided into an inner tube and an outer tube. A liquid interface is arranged parallel to the left end of the spray gun, and the liquid interface is connected to the inner tube of the spray gun. The liquid interface is connected to the urea solution through a liquid connection component. A gas interface is arranged vertically at the lower left end of the spray gun, and the gas interface is connected to the outer tube of the spray gun. The gas interface is connected to compressed air through a gas connection component. A spray gun flange is fitted on the right side of the spray gun. An atomizing nozzle is arranged vertically at the lower right end of the spray gun. Both the inner tube and the outer tube of the spray gun are connected to the atomizing nozzle. The spray gun flange is detachably connected to a sealing component. The left end of the sealing component is set on the outside of the insulation layer of the flue, and the right end is fixedly set in a through hole in the insulation layer of the flue. A protective air interface is arranged vertically at the upper left end of the sealing component, and the protective air interface is connected to the protective air through a protective air connection component. The spray gun at the right end of the spray gun flange passes through the sealing component and extends into the flue.

[0007] The liquid connection assembly includes a first metal hose, which is detachably connected to a liquid interface via a first connector a. One end of the first metal hose is connected to the liquid interface, and the other end is detachably connected to a first check valve via a first connector b. The first check valve is detachably connected to a first ball valve via a first connector c. The first ball valve is connected to a urea solution output pipe via a first connector d.

[0008] The gas connection assembly includes a second metal hose, which is detachably connected to the gas interface via a second connector a. One end of the second metal hose is connected to a liquid interface, and the other end is detachably connected to a second check valve via a second connector b. The second check valve is detachably connected to a second ball valve via a second connector c. The second ball valve is connected to a compressed air output pipe via a second connector d.

[0009] The atomizing nozzle includes a connector that connects to the inner and outer tubes of the spray gun. The inner and outer tubes of the spray gun are detachably connected to the dual-fluid atomizing nozzle via the connector.

[0010] The sealing assembly includes a first sealing flange detachably connected to the spray gun flange. The right end of the first sealing flange is connected to the left end of the protective air duct. A protective air inlet is vertically installed at the upper left end of the protective air duct. The portion of the protective air duct outside the flue insulation layer is wider than the portion of the protective air duct inside the hole that penetrates the flue insulation layer. The right end of the protective air duct is connected to a second sealing flange. The second sealing flange is connected to the furnace body pipe flange. The second sealing flange and the furnace body pipe flange are fixedly installed inside the flue insulation layer.

[0011] The protective air connection assembly includes a third metal hose, which is detachably connected to the protective air interface via a third connector a. One end of the third metal hose is connected to the protective air interface, and the other end is detachably connected to a third ball valve via a third connector b. The third ball valve is connected to the compressed protective air output pipe via a third connector c.

[0012] Metal graphite spiral wound gaskets are installed between the spray gun flange and the first sealing flange, and between the second sealing flange and the furnace body pipe flange.

[0013] The lengths of the gas connection assembly, liquid connection assembly, and protective air connection assembly are all greater than the length of the spray gun.

[0014] The depth of the dual-fluid atomizing nozzle into the furnace body is determined by the number of spray guns. When the number of spray guns is 1, the dual-fluid atomizing nozzle should be located at the center of the furnace body cross-section. When the number of spray guns is ≥2, the length of the spray gun is determined based on flow field simulation. The internal structure of the dual-fluid atomizing nozzle is hollow and conical, which can achieve wide-angle circular spray and 360° annular spray. The dual-fluid atomizing nozzle is equipped with 5-10 spray holes, which can meet the requirements of large flow rate and rapid atomization.

[0015] The beneficial effects of this utility model are as follows:

[0016] 1. The spray gun adopts a liquid rear-entry type, that is, a liquid interface is set parallel to the left end of the spray gun, which is connected to the inner tube of the spray gun. The liquid interface is connected to the urea solution through a liquid connection component. A gas interface is set vertically at the lower left end of the spray gun, which is connected to the outer tube of the spray gun. During normal operation, the pressure of the urea solution is 0.03-0.05MPa greater than the pressure of the compressed air. The compressed air enters the dual-fluid atomizing nozzle before the urea solution, which can improve the atomization effect and enable the urea solution to react quickly when it comes into contact with the flue gas, avoiding some urea falling to the bottom of the flue before it can generate ammonia.

[0017] 2. The portion of the protective duct outside the flue insulation layer is wider than the portion inside the through-hole in the flue insulation layer, which accelerates the airflow. Simultaneously, the connection between the spray gun and the protective duct via the spray gun flange and the first sealing flange maintains a constant spray gun nozzle angle, parallel to the flue gas flow direction. One end of the protective duct is located inside the insulation layer, effectively reducing temperature loss. When replacing the spray gun, opening the third ball valve directs the protective air into the flue, effectively preventing hot air from escaping through the holes in the flue wall where the spray gun is installed, reducing potential safety hazards. The lengths of the gas connection assembly, liquid connection assembly, and protective air connection assembly are all greater than the length of the spray gun, facilitating spray gun replacement.

[0018] 3. Metal graphite spiral wound gaskets are installed between the spray gun flange and the first sealing flange, and between the second sealing flange and the furnace body pipe flange to meet the furnace body's temperature resistance requirement of 500-600℃. Attached Figure Description

[0019] Figure 1 This is a cross-sectional structural diagram of the present invention;

[0020] Figure 2 This is a cross-sectional view of the spray gun of this utility model;

[0021] Figure 3 This is an exploded structural diagram of the liquid connection assembly of this utility model;

[0022] Figure 4 This is an exploded structural diagram of the gas connection assembly of this utility model;

[0023] Figure 5 This is a schematic diagram of the exploded structure of the protective wind connection assembly of this utility model;

[0024] Figure 6 This is a schematic diagram of the sealing component structure of this utility model.

[0025] Reference numerals: 1. Spray gun; 11. Inner tube; 12. Outer tube; 13. Spray gun flange; 14. Liquid interface; 15. Gas interface; 16. Atomizing nozzle; 161. Connector; 162. Dual-fluid atomizing nozzle; 2. Liquid connection assembly; 21. First metal hose; 22. First check valve; 23. First ball valve; 24. First connector a; 25. First connector b; 26. First connector c; 27. First connector d; 3. Gas connection assembly; 31. Second metal hose; 32. Second check valve 33. Second ball valve; 34. Second connector a; 35. Second connector b; 36. Second connector c; 37. Second connector d; 4. Protective air connection assembly; 41. Third metal hose; 42. Third ball valve; 43. Third connector a; 44. Third connector b; 45. Third connector c; 5. Sealing assembly; 51. First sealing flange; 52. Protective air duct; 53. Second sealing flange; 54. Furnace body port flange; 55. Protective air interface; 6. Metal graphite spiral wound gasket; 7. Insulation layer. Detailed Implementation

[0026] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0027] like Figure 1-2As shown, a urea spray gun for flue gas denitrification includes a spray gun 1, which is divided into an inner tube 11 and an outer tube 12. A liquid interface 14 is arranged parallel to the left end of the spray gun 1, and the liquid interface 14 is connected to the inner tube 11 of the spray gun 1. The liquid interface 14 is connected to a urea solution through a liquid connection assembly 2. A gas interface 15 is arranged vertically at the lower left end of the spray gun 1, and the gas interface 15 is connected to the outer tube 12 of the spray gun 1. The gas interface 15 is connected to compressed air through a gas connection assembly 3. A spray gun flange 13 is fitted on the spray gun 1 to the right of the gas interface 15. An atomizing nozzle 16 is arranged vertically at the lower right end of the spray gun 1. The atomizing nozzle 16 includes a connection between the inner tube 11 and the outer tube 12 of the spray gun 1. The inner tube 11 and outer tube 12 of the spray gun 1 are detachably connected to the dual-fluid atomizing nozzle 162 via the connector 161. The number of spray guns 1 is 1, and the dual-fluid atomizing nozzle 162 is located at the center of the furnace body cross-section. The spray gun flange 13 is detachably connected to the sealing assembly 5. The left end of the sealing assembly 5 is located on the outside of the insulation layer 7 of the flue, and the right end is fixedly located in the through hole opened in the insulation layer 7 of the flue. A protective air interface 55 is vertically arranged on the upper left end of the sealing assembly 5. The protective air interface 55 is connected to the protective air via the protective air connection assembly 4. The spray gun 1 at the right end of the spray gun flange 13 passes through the sealing assembly 5 and extends into the flue.

[0028] like Figure 3 As shown, the liquid connection assembly 2 includes a first metal hose 21, which is detachably connected to the liquid interface 14 via a first connector a24. One end of the first metal hose 21 is connected to the liquid interface 14, and the other end is detachably connected to a first check valve 22 via a first connector b25. The first check valve 22 is detachably connected to a first ball valve 23 via a first connector c26. The first ball valve 23 is connected to the urea solution output pipe via a first connector d27.

[0029] like Figure 4 As shown, the gas connection assembly 3 includes a second metal hose 31, which is detachably connected to the gas interface 15 via a second connector a34. One end of the second metal hose 31 is connected to the liquid interface 14, and the other end is detachably connected to the second check valve 32 via a second connector b35. The second check valve 32 is detachably connected to the second ball valve 33 via a second connector c36, and the second ball valve 33 is connected to the compressed air output pipe via a second connector d37.

[0030] like Figure 1 and Figure 6As shown, the sealing assembly 5 includes a first sealing flange 51 detachably connected to the spray gun flange 13. The right end of the first sealing flange 51 is connected to the left end of the protective air duct 52. The portion of the protective air duct 52 located outside the flue insulation layer 7 is wider than the portion of the protective air duct 52 located inside the hole opened through the flue insulation layer 7. The right end of the protective air duct 52 is connected to a second sealing flange 53. The second sealing flange 53 is connected to the furnace body pipe flange 54. The second sealing flange 53 and the furnace body pipe flange 54 are fixedly installed inside the flue insulation layer 7.

[0031] like Figure 5 and Figure 6 As shown, the protective air connection assembly 4 includes a third metal hose 41. The third metal hose 41 is detachably connected to the protective air interface 55 via a third connector a43. One end of the third metal hose 41 is connected to the protective air interface 55, and the other end is detachably connected to the third ball valve 42 via a third connector b44. The third ball valve 42 is connected to the compressed protective air output pipe via a third connector c45.

[0032] like Figure 1 , Figure 2 and Figure 6 Metal graphite spiral wound gaskets 6 are installed between the spray gun flange 13 and the first sealing flange 51, and between the second sealing flange 53 and the furnace body pipe flange 54.

[0033] like Figure 1 As shown, the lengths of the gas connection assembly 3, the liquid connection assembly 2, and the protective air connection assembly 4 are all greater than the length of the spray gun 1.

[0034] This urea spray gun for flue gas denitrification operates by opening the first ball valve 23 and the second ball valve 33, allowing urea solution to enter the inner tube 11 of the spray gun 1, and compressed air to enter the outer tube 12 of the spray gun 1. The urea solution is then sprayed onto the flue gas through the dual-fluid atomizing nozzle 162. When the spray gun 1 needs replacement or repair, the first ball valve 23 and the second ball valve 33 are closed, the spray gun flange 13 is removed from the first sealing flange 51, and the third ball valve 42 is opened. Protective air is then blown into the flue gas through the protective air duct 52 to prevent the high-temperature flue gas from escaping. The operator then removes the liquid connection assembly 2 and the gas connection assembly 3, and takes out the spray gun 1 for replacement or repair. This invention features a simple structure, ease of use, and excellent atomization effect, enabling the urea solution to react quickly with the flue gas, preventing some urea from falling to the bottom of the flue gas before ammonia is generated. The protective air design effectively prevents hot air from escaping from the holes in the flue gas duct wall where the spray gun is installed, reducing potential safety hazards.

Claims

1. A urea spray gun for flue gas denitrification, comprising a spray gun (1), wherein the spray gun (1) is divided into an inner tube (11) and an outer tube (12), characterized in that: A liquid inlet (14) is provided parallel to the left end of the spray gun (1). The liquid inlet (14) is connected to the inner tube (11) of the spray gun (1). The liquid inlet (14) is connected to the urea solution through the liquid connection assembly (2). A gas inlet (15) is provided vertically at the lower left end of the spray gun (1). The gas inlet (15) is connected to the outer tube (12) of the spray gun (1). The gas inlet (15) is connected to compressed air through the gas connection assembly (3). A spray gun flange (13) is fitted on the spray gun (1) to the right of the gas inlet (15). An atomizing nozzle (1) is provided vertically at the lower right end of the spray gun (1). 6) The inner tube (11) and outer tube (12) of the spray gun (1) are both connected to the atomizing nozzle (16); the spray gun flange (13) is detachably connected to the sealing assembly (5). The left end of the sealing assembly (5) is set on the outside of the insulation layer (7) of the flue, and the right end is fixedly set in the hole opened through the insulation layer (7) of the flue. The upper left end of the sealing assembly (5) is vertically set with a protective air interface (55). The protective air interface (55) is connected to the protective air through the protective air connection assembly (4); the spray gun (1) at the right end of the spray gun flange (13) passes through the sealing assembly (5) and extends into the flue.

2. The urea spray gun for flue gas denitrification according to claim 1, characterized in that: The liquid connection assembly (2) includes a first metal hose (21), which is detachably connected to the liquid interface (14) via a first connector a (24). One end of the first metal hose (21) is connected to the liquid interface (14), and the other end is detachably connected to the first check valve (22) via a first connector b (25). The first check valve (22) is detachably connected to the first ball valve (23) via a first connector c (26). The first ball valve (23) is connected to the urea solution output pipe via a first connector d (27).

3. The urea spray gun for flue gas denitrification according to claim 1, characterized in that: The gas connection assembly (3) includes a second metal hose (31), which is detachably connected to the gas interface (15) via a second connector a (34). One end of the second metal hose (31) is connected to the liquid interface (14), and the other end is detachably connected to the second check valve (32) via a second connector b (35). The second check valve (32) is detachably connected to the second ball valve (33) via a second connector c (36). The second ball valve (33) is connected to the compressed air output pipe via a second connector d (37).

4. The urea spray gun for flue gas denitrification according to claim 1, characterized in that: The protective air connection assembly (4) includes a third metal hose (41), which is detachably connected to the protective air interface (55) via a third connector a (43). One end of the third metal hose (41) is connected to the protective air interface (55), and the other end is detachably connected to the third ball valve (42) via a third connector b (44). The third ball valve (42) is connected to the compressed protective air output pipe via a third connector c (45).

5. The urea spray gun for flue gas denitrification according to claim 1, characterized in that: The sealing assembly (5) includes a first sealing flange (51) detachably connected to the spray gun flange (13). The right end of the first sealing flange (51) is connected to the left end of the protective air duct (52). The upper left end of the protective air duct (52) is vertically provided with a protective air interface (55). The part of the protective air duct (52) located outside the flue insulation layer (7) is wider than the part of the protective air duct (52) located in the hole opened through the flue insulation layer (7). The right end of the protective air duct (52) is connected to a second sealing flange (53). The second sealing flange (53) is connected to the furnace body pipe flange (54). The second sealing flange (53) and the furnace body pipe flange (54) are fixedly installed in the insulation layer (7) of the flue.

6. The urea spray gun for flue gas denitrification according to claim 1, characterized in that: The atomizing nozzle (16) includes a connector (161) that connects to the inner tube (11) and outer tube (12) of the spray gun (1). The inner tube (11) and outer tube (12) of the spray gun (1) are detachably connected to the dual-fluid atomizing nozzle (162) via the connector (161).

7. The urea spray gun for flue gas denitrification according to claim 5, characterized in that: Metal graphite spiral wound gaskets (6) are provided between the spray gun flange (13) and the first sealing flange (51) and between the second sealing flange (53) and the furnace body pipe flange (54).

8. The urea spray gun for flue gas denitrification according to claim 1, characterized in that: The lengths of the gas connection assembly (3), the liquid connection assembly (2), and the protective air connection assembly (4) are all greater than the length of the spray gun (1).

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