Staged burner and steam coil thereof

Abstract

The utility model provides a staged burner and a steam coil thereof. The steam coil pipe comprises a water inlet pipe, a heated coil pipe and a steam ejection ring pipe which are sequentially connected, the heated coil pipe is spiral, the diameter of the inner ring contour of the steam ejection ring pipe is larger than that of the outer ring contour of the heated coil pipe, and a plurality of steam outlet holes are formed in the steam ejection ring pipe. Water enters from a water inlet pipe of the steam coil pipe to cool primary flame combusted in the fire protection barrel, local high temperature is prevented, NOx emission of a primary combustion area is reduced, meanwhile, steam generated by heating is sprayed out from a steam outlet hole of the steam spraying ring pipe, and the steam and secondary air participate in secondary combustion after being mixed in a secondary air shell. OH and H groups generated by decomposition of the water vapor can be subjected to chain reaction with CO generated by primary combustion, the reducing atmosphere is enhanced, NO in-phase reduction reaction is facilitated, meanwhile, H and OH free radicals generated by dissociation of the water vapor can inhibit oxidation of HCN to NO, and the generation amount of NO is reduced under the combined action of the H and OH free radicals and the CO free radicals.

Description

Technical Field

[0001] This utility model relates to the field of burner technology, specifically to a staged burner and its steam coil. Background Technology

[0002] With increasing environmental awareness, reducing NOx emissions from burners has been a persistent focus in this field. While existing technologies document the mechanism of water vapor in NOx control, there is a lack of research on applying water vapor to reduce NOx emissions in burners. Therefore, there is an urgent need to propose a technical solution for reducing NOx emissions from burners using water vapor. Utility Model Content

[0003] In order to overcome the shortcomings of the prior art, the purpose of this utility model is to provide a staged burner and its steam coil.

[0004] To achieve the above objectives, the technical solution adopted by this utility model to solve its technical problem is: a steam coil, comprising a water inlet pipe, a heating coil, and a steam ejection ring pipe connected in sequence, wherein the heating coil is spiral in shape, the inner ring diameter of the steam ejection ring pipe is larger than the outer ring diameter of the heating coil, and the steam ejection ring pipe is provided with multiple steam outlet holes.

[0005] Furthermore, the heated coil includes an outer spiral coil and an inner spiral coil connected together, wherein the inner diameter of the outer spiral coil is larger than the outer diameter of the inner spiral coil.

[0006] Furthermore, the water inlet pipe is equipped with a flow regulating valve.

[0007] A staged burner includes a secondary air shell, a flame shield, a gas gun, and a steam coil. The flame shield is installed inside the secondary air shell, the front end of the gas gun is located inside the flame shield, the heating coil of the steam coil is located inside the flame shield, and the steam ejection ring of the steam coil is located between the secondary air shell and the flame shield.

[0008] Furthermore, it also includes an air inlet housing, which has a first air inlet for inputting combustion-supporting gas, and a second air inlet at the tail of the fire shield. The secondary air housing is installed at the front end of the air inlet housing. Part of the combustion-supporting gas input from the first air inlet enters the space between the secondary air housing and the fire shield, and the other part enters the inner cavity of the fire shield through the second air inlet.

[0009] Furthermore, the gas gun is movably mounted on the fixed sleeve of the air inlet housing, and the displacement drive mechanism is used to drive the gas gun to move back and forth along the axis of the flame shield.

[0010] Furthermore, the gas gun is provided with a gas inlet for inputting gas, and the gas gun is also provided with a spark plug for ignition. The front end of the gas gun is provided with a gas nozzle, and the gas nozzle includes a plurality of first gas holes that are forward along the axial direction, a plurality of second gas holes that are set at 45° with the axial direction, and a plurality of third gas holes that are set at 90° with the axial direction.

[0011] Furthermore, a flow equalization plate is provided inside the fire shield tube behind the gas nozzle.

[0012] Furthermore, the front end of the fire shield is provided with a forward-shrinking inward portion.

[0013] Furthermore, an inwardly retracting retaining ring is provided on the inner wall of the secondary air casing at a position corresponding to the inwardly retracting portion.

[0014] Using the technical solution of this utility model, water enters from the inlet pipe of the steam coil, cooling the primary flame burning inside the flame shield to prevent local high temperatures and reduce NOx emissions in the primary combustion zone. At the same time, the water vapor generated by the heating is ejected from the steam outlet hole of the steam ejection ring pipe. The water vapor mixes with the secondary air in the secondary air shell and participates in the secondary combustion. The OH and H groups generated by the decomposition of water vapor can initiate a chain reaction with the CO generated by the primary combustion, enhancing the reducing atmosphere and facilitating the occurrence of the NO homogeneous reduction reaction. Meanwhile, the H and OH free radicals generated by the dissociation of water vapor can inhibit the oxidation of HCN to NO. Their combined effect reduces the amount of NO generated. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the burner of this utility model.

[0017] Figure 2 This is one of the cross-sectional views of the burner of this utility model.

[0018] Figure 3 This is the second cross-sectional view of the burner of this utility model.

[0019] Figure 4 This is a schematic diagram of the steam coil structure.

[0020] Figure 5 This is a structural schematic diagram of the gas gun and its shifting drive mechanism.

[0021] The numbers and letters in the diagram represent the names of the corresponding components:

[0022] 10-Air inlet housing; 11-First air inlet; 12-Fixing sleeve; 20-Secondary air housing; 21-Inner retractable retaining ring; 30-Flame shield; 31-Second air inlet; 32-Flow equalization orifice plate; 33-Inner retractable part; 40-Steam coil; 41-Water inlet pipe; 42-Heating coil; 421-Outer spiral coil; 422-Inner spiral coil; 43-Steam ejection ring pipe; 431-Steam outlet hole; 44-Flow regulating valve; 50-Gas gun; 51-Gas inlet; 52-Gas nozzle; 521-First gas hole; 522-Second gas hole; 523-Third gas hole; 53-Spark plug; 60-Shifting drive mechanism; 61-Screw motor; 62-Screw; 63-Ear plate. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] For ease of description of technical features, the directional descriptions of "front" and "rear" in this utility model refer to the direction in which the flame of the ignition gun is emitted as the front.

[0025] like Figure 4 As shown, one embodiment of this utility model is: a steam coil 40, including a water inlet pipe 41, a heating coil 42 and a steam ejection ring pipe 43 connected in sequence. The heating coil 42 is spiral in shape, and the inner circle diameter of the steam ejection ring pipe 43 is larger than the outer circle diameter of the heating coil 42. The steam ejection ring pipe 43 is provided with a plurality of steam outlet holes 431.

[0026] like Figure 1-5 As shown, one embodiment of this utility model is: a staged burner, including an air inlet shell 10, a steam coil 40, a secondary air shell 20, a fire shield 30, a gas gun 50, and a shifting drive mechanism 60.

[0027] The air inlet housing 10 is provided with a first air inlet 11 for inputting combustion-supporting gas, and the tail end of the fire shield 30 is provided with a second air inlet 31. The secondary air housing 20 is installed at the front end of the air inlet housing 10, and the fire shield 30 is installed inside the secondary air housing 20. Part of the combustion-supporting gas input from the first air inlet 11 enters the space between the secondary air housing 20 and the fire shield 30, and the other part enters the inner cavity of the fire shield 30 through the second air inlet 31.

[0028] The gas gun 50 is provided with a gas inlet 51 for inputting gas, a gas nozzle 52 at the front end of the gas gun 50, and a spark plug 53 for ignition. The gas gun 50 is movably mounted on the fixed sleeve 12 of the air inlet housing 10. The front end of the gas gun 50 is located in the inner cavity of the flame shield 30. The shifting drive mechanism 60 is used to drive the gas gun 50 to move back and forth along the axial direction of the flame shield 30.

[0029] The steam coil 40 includes a water inlet pipe 41, a heating coil 42 and a steam ejection ring pipe 43 connected in sequence. The heating coil 42 is located in the inner cavity of the fire shield 30, and the steam ejection ring pipe 43 is located between the secondary air shell 20 and the fire shield 30. The steam ejection ring pipe 43 is provided with a plurality of steam outlet holes 431 facing forward.

[0030] The beneficial effects of adopting the above technical solution are as follows: Water enters from the inlet pipe of the steam coil, cooling the primary flame burning inside the flame shield, preventing localized high temperatures, and reducing NOx emissions in the primary combustion zone. Simultaneously, the steam generated by the heating is ejected from the steam outlet hole of the steam ejection ring pipe. The steam mixes with secondary air in the secondary air shell and participates in secondary combustion. The OH and H groups produced by the decomposition of the steam can initiate a chain reaction with the CO produced in the primary combustion. The reactions H+O2→OH+O and O+H2→OH+H enhance the reducing atmosphere, facilitating the homogeneous reduction reaction of NO. Simultaneously, the H and OH free radicals generated from the dissociation of water vapor inhibit the oxidation of HCN to NO, resulting in a reduction in NO formation. The shifting drive mechanism moves the gas gun axially back and forth, controlling the flame position to suit different combustion power levels. At low power, the gas gun can be moved backward to increase the heat exchange area and ensure that the water in the steam coil is fully heated to convert into superheated steam; at high power, the gas gun is moved forward to prevent insufficient primary flame cooling and coil damage due to overheating of the steam coil.

[0031] like Figure 2 , 4 As shown, in some other embodiments of this utility model, a flow regulating valve 44 is provided on the water inlet pipe 41 of the steam coil 40. The beneficial effects of adopting the above technical solution are: it facilitates the adjustment of the amount of steam generated according to changes in combustion power and air-fuel ratio. Increasing the water flow rate at high power suppresses the occurrence of high-temperature zones, while simultaneously maintaining a reasonable ratio between the amount of steam and the total amount of flue gas generated by combustion, thereby improving the effect of reducing NOx emissions.

[0032] In some other embodiments of this invention, the volume of water vapor generated by the steam coil 40 accounts for 5%-8% of the total flue gas volume generated by combustion. The beneficial effect of adopting the above technical solution is that a reasonable proportion range has a better effect on reducing NOx emissions.

[0033] In some other embodiments of this invention, a detector is also included for detecting the temperature of the heated coil 42. The advantages of adopting the above technical solution are: it facilitates monitoring the temperature of the heated coil, preventing insufficient primary flame cooling and damage to the heated coil due to overheating.

[0034] like Figure 2 As shown, in some other embodiments of this utility model, a flow equalization plate 32 is provided inside the flame shield 30 behind the gas nozzle 52. The beneficial effects of adopting the above technical solution are: improving the uniformity of the combustion-supporting gas entering the gas nozzle and improving the stability of flame establishment.

[0035] In some other embodiments of this invention, the flow rate of the combustion-supporting gas entering the inner cavity of the flame shield 30 through the second air inlet 31 accounts for 40%-45% of the total flow rate of the combustion-supporting gas input from the first air inlet 11. The beneficial effects of adopting the above technical solution are: improving the staged combustion effect, reducing the flame temperature, and reducing NOx emissions.

[0036] like Figure 3 , 4 As shown, in some other embodiments of this utility model, the heating coil 42 of the steam coil includes an outer spiral coil 421 and an inner spiral coil 422 connected to each other, wherein the inner diameter of the outer spiral coil 421 is larger than the outer diameter of the inner spiral coil 422. The beneficial effects of adopting the above technical solution are: improved heating effect and uniformity of primary flame cooling.

[0037] In some other embodiments of this utility model, the outer ring diameter of the outer spiral coil 421 is 75%-90% of the inner diameter of the flame shield 30, the inner ring diameter of the inner spiral coil 422 is 45%-55% of the inner diameter of the flame shield 30, and the distance between the inner ring of the outer spiral coil 421 and the outer ring of the inner spiral coil 422 is greater than 5mm. The beneficial effect of adopting the above technical solution is that it maintains both flame stability and flame cooling effect in a relatively optimal state.

[0038] like Figure 4 As shown, in some other embodiments of this utility model, the plurality of steam outlet holes 431 on the steam ejection ring pipe 43 are distributed in a circular pattern. The beneficial effect of adopting the above technical solution is to improve the uniformity of water vapor ejection.

[0039] like Figure 2 , 3 As shown, in some other embodiments of this utility model, the front end of the fire shield 30 is provided with a forward-shrinking inward portion 33.

[0040] like Figure 2 , 3As shown, in some other embodiments of this utility model, an inwardly retracting retaining ring 21 is provided on the inner wall of the secondary air housing 20 at a position corresponding to the inwardly retracting portion 33.

[0041] like Figure 3 As shown, in some other embodiments of this utility model, with the diameter of the circumference of the center of the plurality of steam outlet holes 431 as D1, the outer diameter of the fire shield 30 as D2, and the inner diameter of the secondary air shell 20 as D3, then (D2+D3) / 2≤D1≤1.1*(D2+D3) / 2. With the outer diameter of the steam ejection ring pipe 43 as d, then (D3-D2) / 6≤d≤(D3-D2) / 3. The angle between the conical surface of the inward-retracting part 33 and the axial direction is 30°-45°, and the axial length of the inward-retracting part 33 is 10%D2-20%D2. The angle between the conical surface of the inward-retracting retaining ring 21 and the axial direction is 30°-45°, and with the inner diameter of the small opening at the front end of the inward-retracting retaining ring 21 as D4, then 0.95*(D2+D3) / 2≤D4≤1.05*(D2+D3) / 2. The beneficial effects of adopting the above technical solution are: the steam ejection ring pipe provides a certain resistance in the secondary air duct to achieve the rectification effect of the secondary air, and cooperates with the inner recess of the fire shield and the inner recess of the secondary air shell to ensure the mixing effect of water vapor and secondary air without generating excessive resistance to the secondary air, thereby further improving the effect of using water vapor to reduce NOx emissions.

[0042] like Figure 5 As shown, in some other embodiments of this utility model, the gas nozzle 52 includes a plurality of first gas holes 521 extending forward along the axial direction, a plurality of second gas holes 522 arranged at 45° to the axial direction, and a plurality of third gas holes 523 arranged at 90° to the axial direction. The beneficial effect of adopting the above technical solution is that the gas holes in the three directions of the gas nozzle cooperate with the double-layer heating coil to ensure a uniform temperature field.

[0043] In some other embodiments of this utility model, the total opening area of ​​the first gas hole 521 accounts for 40%-50% of the total opening area of ​​all gas holes.

[0044] In some other embodiments of this utility model, the total opening area of ​​the second gas hole 522 is 0.8-1.2 times the total opening area of ​​the third gas hole 523.

[0045] like Figure 5 As shown, in some other embodiments of this utility model, the shifting drive mechanism 60 includes a lead screw motor 61 connected to the fixed sleeve 12, and an ear plate 63 with a threaded hole is fixedly connected to the body of the gas gun 50. The lead screw 62 of the lead screw motor is connected to the threaded hole of the ear plate 63. The beneficial effects of adopting the above technical solution are: compact structure, and the ability to quickly adjust the forward and backward position of the gas gun.

[0046] The above embodiments are only for illustrating the technical concept and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it. They should not be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the protection scope of this utility model.

Claims

1. A steam coil, characterized in that, It includes a water inlet pipe, a heating coil and a steam ejection ring pipe connected in sequence. The heating coil is spiral in shape. The inner diameter of the steam ejection ring pipe is larger than the outer diameter of the heating coil. The steam ejection ring pipe is provided with multiple steam outlet holes.

2. The steam coil according to claim 1, characterized in that, The heated coil includes an outer spiral coil and an inner spiral coil connected together, wherein the inner diameter of the outer spiral coil is larger than the outer diameter of the inner spiral coil.

3. The steam coil according to claim 1, characterized in that, The inlet pipe is equipped with a flow regulating valve.

4. A staged burner, characterized in that, It includes a secondary air housing, a flame shield, a gas gun, and a steam coil as described in any one of claims 1-3. The flame shield is installed inside the secondary air housing, the front end of the gas gun is located inside the flame shield, the heating coil of the steam coil is located inside the flame shield, and the steam ejection ring of the steam coil is located between the secondary air housing and the flame shield.

5. The staged burner according to claim 4, characterized in that, It also includes an air inlet housing, which has a first air inlet for inputting combustion-supporting gas, and a second air inlet at the tail of the fire shield. The secondary air housing is installed at the front end of the air inlet housing. Part of the combustion-supporting gas input from the first air inlet enters the space between the secondary air housing and the fire shield, and the other part enters the inner cavity of the fire shield through the second air inlet.

6. The staged burner according to claim 5, characterized in that, It also includes a shifting drive mechanism, wherein the gas gun is movably mounted on the fixed sleeve of the air inlet housing, and the shifting drive mechanism is used to drive the gas gun to move back and forth along the axis of the fire shield.

7. The staged burner according to claim 6, characterized in that, The gas gun is provided with a gas inlet for inputting gas, and the gas gun is also provided with a spark plug for ignition. The front end of the gas gun is provided with a gas nozzle, which includes a plurality of first gas holes that are forward along the axial direction, a plurality of second gas holes that are set at 45° with the axial direction, and a plurality of third gas holes that are set at 90° with the axial direction.

8. The staged burner according to claim 5, characterized in that, The fire shield is equipped with a flow equalization plate located behind the gas nozzle.

9. The staged burner according to claim 4, characterized in that, The front end of the fire shield is provided with a forward-shrinking inward section.

10. The staged burner according to claim 9, characterized in that, An inwardly retracting retaining ring is provided on the inner wall of the secondary air casing at a position corresponding to the inwardly retracting portion.

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