A large burner for rotary kiln

Abstract

The present invention discloses a large-scale burner for a rotary kiln, which belongs to the field of industrial combustion technology, and includes a furnace tube, an air inlet pipe is arranged inside the furnace tube, and an air inlet pipe is arranged on the furnace tube in communication, an air supply pipe is arranged on the outer side of the air inlet pipe, and there is a gap between the air supply pipe and the air inlet pipe, and the wind introduced on the air inlet pipe will pass through the gap between the air supply pipe and the air inlet pipe and enter the air supply pipe to be premixed with the fuel gas; a guide pipe is arranged at the end of the air supply pipe, and an igniter is arranged on the guide pipe. The present invention is used to solve the problem of poor mixing efficiency caused by an overly long burner, which leads to low combustion efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial combustion, and in particular relates to a large burner for a rotary kiln. Background Art

[0002] In the industrial field, rotary kiln plays a pivotal role. It is a large thermal equipment used for primary processing of powder or mineral raw materials. This equipment can use gas as a heat source, so it is an indispensable component to be equipped with a dedicated gas burner.

[0003] Considering the long design of the rotary kiln, the burner is also longer than ordinary burners so that the gas can be transported to the heating area. Generally, a swirler is installed on one side of the burner's combustion port. This design helps to accelerate the mixing of gas and air and ensure the adequacy of the combustion process.

[0004] However, although the burner inside the rotary kiln is also equipped with a swirler at the combustion port in order to achieve a good mixing effect, compared with ordinary burners, the length of the rotary kiln burner will have more contact friction with the gas and air, which will hinder the mixing process to a certain extent, resulting in poor mixing of gas and air, and thus affecting the combustion efficiency of the gas. Insufficient combustion will not only lead to an increase in the content of CO and NOx in the flue gas, but also weaken the rigidity of the flame, ultimately affecting the utilization efficiency of thermal energy. Therefore, optimizing the burner design of the rotary kiln to improve the mixing efficiency of gas and air is crucial to improving the energy utilization efficiency and environmental performance of the entire system. Summary of the invention

[0005] In view of the above problems, the present invention provides a large burner for a rotary kiln, which is used to solve the problem of poor mixing efficiency caused by an overly long burner, thereby causing low combustion efficiency.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A large burner for a rotary kiln comprises a furnace tube, an air inlet pipe is arranged in the furnace tube, and an air inlet pipe is arranged on the furnace tube in communication, an air supply pipe is sleeved on the outer side of the air inlet pipe, and there is a gap between the air supply pipe and the air inlet pipe, and the wind introduced on the air inlet pipe will pass through the gap between the air supply pipe and the air inlet pipe and enter the air supply pipe to be premixed with the fuel gas;

[0008] A flow guide pipe is arranged at the end of the air supply pipe, and an igniter is arranged on the flow guide pipe.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: by arranging an air supply pipe on the air intake pipe, a cavity is formed between the air intake pipe and the air supply pipe, and air can be mixed with the gas in the air supply pipe from the gap between the air supply pipe and the air intake pipe. In addition, in some cases, the air introduced into the furnace pipe can be sucked into the air supply pipe through the cavity to participate in the mixing under the influence of the high-speed airflow in the air supply pipe while the gas pressure is kept constant and the air fluctuates, thereby achieving the purpose of premixing and maintaining the effect of premixing without excessive deviation. Moreover, the premixing position is set at The position close to the air intake and air inlet allows the gas and air to contact and mix under high-speed movement, avoiding the speed reduction of the mixed air and gas when passing through the extra-long furnace tube, thereby preventing poor mixing effect during combustion; the air intake pipe is sleeved in the air supply pipe, and the air entering the air intake pipe wraps the gas in the middle position and is continuously mixed under the influence of the gas transportation process. In addition, the long and straight air intake pipe and air supply pipe can reduce the contact friction between the mixed air and gas and the side wall, thereby reducing the mechanical loss of the airflow and maintaining the rigidity and stability of the flame during the gas combustion process.

[0010] As a further improvement of the above scheme, a plurality of spirally arranged first flow guide members are provided on the surface of the air outlet end of the air inlet pipe, and a plurality of second flow guide members which can be screwed in and out with the first flow guide members are provided on the inner wall of the air inlet end of the air supply pipe, and the first flow guide members and the second flow guide members are both located in the gap between the air supply pipe and the air inlet pipe.

[0011] The technical effect of the above improvement is: by providing the first guide member and the second guide member, the air entering the air supply pipe can be mixed with the fuel gas in a swirl manner, thereby increasing the uniformity of the mixing and improving the combustion efficiency.

[0012] As a further improvement of the above scheme, the end of the air supply pipe for combustion is provided with an inwardly contracted opening, and a plurality of through holes penetrating inside and outside are provided on the side close to the contracted opening;

[0013] A plurality of first swirl sheets are arranged on the inner wall of the air supply pipe at one end of the burner, and a swirler is also arranged between the guide pipe and the air supply pipe.

[0014] The technical effect of the above improvement is: through the guidance of the first swirl plate, the ejected gas can be ejected in a swirl manner, so as to be easier to mix and ignite with the introduced air, and the through holes can make the gas diffuse to the surroundings into the air, thereby increasing the mixing effect between the gas and the air, making the gas more conducive to combustion.

[0015] As a further improvement of the above scheme, a diverter is also provided in the guide pipe, and the diverter is arranged toward the air supply pipe. The diverter includes a plurality of guide plates fixed to the inner wall of the igniter, and the plurality of guide plates extend toward the middle and are fixed to each other, and a guide hole is provided in the middle position where they are fixed to each other.

[0016] The technical effect of the above improvement is that the guide holes and the guide plates can have a stratified effect on the gas ejected from the gas supply pipe, that is, the gas in the middle is directly ejected outward in a direct flow manner, and the gas around is mixed with the air and then ejected in a swirl manner, so that after the gas is ignited, the flame can present an olive leaf shape with a thick middle and pointed ends, thereby improving the rigidity of the flame and maintaining a high combustion efficiency.

[0017] As a further improvement of the above solution, a contraction section is provided on the guide pipe, the contraction section is close to the combustion port of the air supply pipe, and a penetrating air outlet is provided on the contraction section, and the air outlet faces the diverter.

[0018] The technical effect of the above improvement is: the guide tube plays a role in layered air transportation, thereby ensuring that air can be replenished at different positions of the flame, and the air outlet is arranged on the contraction section, so that the air can be sprayed to the diverter while replenishing the flame, which can cool the diverter.

[0019] As a further improvement of the above scheme, a plurality of first return air holes penetrating inside and outside are arranged on the furnace tube, and an isolation piece covering the first return air holes is fixedly arranged on the inner wall of the furnace tube, and the windward side of the isolation piece is an inclined surface fixedly contacting with the furnace tube.

[0020] The technical effect of the above improvement is: through the first return air hole, the air outside the furnace tube or part of the flue gas after combustion can be returned to the furnace tube to continue to participate in the combustion during the combustion process. The air flow rate in the furnace tube is fast, which can automatically absorb the air and flue gas outside the furnace tube. Since the outside air and flue gas are in the rotary kiln, their temperature is relatively high, and after flowing back into the furnace tube, they can preheat the fuel gas and air.

[0021] As a further improvement of the above solution, an extension furnace tube is sleeved on the end of the furnace tube, the end of the extension furnace tube and the furnace tube are slidably arranged with each other, a gap is arranged between the extension furnace tube and the furnace tube, and a second swirl sheet is fixedly arranged between the extension furnace tube and the guide tube;

[0022] An inwardly contracted necking section is arranged on the end of the extended furnace tube located at the combustion position, and the expanding section is connected to the necking section.

[0023] As a further improvement of the above solution, a plurality of penetrating second air return holes are further provided on the extended furnace tube, and wind shielding plates are further provided at the sides of the second air return holes.

[0024] The technical effect of the above improvement is: the extended furnace tube can extend the furnace tube, so it can be adjusted for rotary furnaces of different lengths. The second return air hole can also allow the smoke and air in the rotary furnace to flow back into the furnace tube to participate in the combustion during the combustion process. The necking section can converge the final air to the middle, so that the air can participate in the combustion. The expansion section is mainly to facilitate the flame to spread outward and burn.

[0025] As a further improvement of the above solution, a pull rod is fixedly provided at the end of the air supply pipe, and after the pull rod passes through the furnace pipe, a driving source is connected to drive it to slide along the axial direction of the air supply pipe;

[0026] The end of the air supply pipe is also provided with an adjustment component for controlling the air volume.

[0027] The technical effect of the above improvement is: by pulling the pull rod, the length of the extended furnace tube can be controlled, and at the same time, the air volume entering the air supply pipe can be adjusted and controlled by controlling the adjustment component.

[0028] As a further improvement of the above solution, the furnace pipe is fixedly arranged on the mobile cart, the air inlet pipe is connected with a regulating valve, and the air inlet end of the air inlet pipe is connected with a metal hose;

[0029] Along the gas inlet direction, a ball valve, a flow meter, a pressure gauge, a shut-off valve and a relief valve connected to the metal hose are sequentially arranged at the gas inlet front end of the metal hose.

[0030] The technical effect of the above improvement is that the mobile cart can support the furnace tubes to facilitate use in different rotary furnaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 It is a cross-sectional schematic diagram of the first structure in the furnace tube of the present invention;

[0033] Figure 3 for Figure 2 A schematic diagram of the local enlarged structure at point A in the middle;

[0034] Figure 4 is a cross-sectional schematic diagram of a second structure in a furnace tube of the present invention;

[0035] Figure 5 for Figure 4 A schematic diagram of the local enlarged structure at B in the middle;

[0036] Figure 6 for Figure 4 A schematic diagram of the local enlarged structure at C in the middle;

[0037] Figure 7 for Figure 6 Schematic diagram of the cross-sectional structure in the DD direction.

[0038] In the figure: 10, furnace tube; 101, first return air hole; 11, air inlet pipe; 12, air inlet pipe; 13, air supply pipe; 131, contraction; 132, through hole; 133, first swirl plate; 14, first guide member; 15, guide pipe; 151, contraction section; 152, air outlet; 16, igniter; 17, second guide member; 18, swirl device; 19, splitter; 191, guide hole; 192, guide plate; 20, Isolation piece; 21, extended furnace tube; 211, necking section; 212, flaring section; 213, second return air hole; 214, wind shield; 215, second swirl plate; 22, regulating valve; 23, metal hose; 24, pull rod; 25, mobile cart; 26, ball valve; 27, flow meter; 28, pressure gauge; 29, shut-off valve; 30, relief valve; 31, movable ring; 32, baffle; 33, limit ring; 34, gear. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solution, the present invention is described in detail below in conjunction with embodiments. The description in this section is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention. Example

[0040] like Figure 1-3 As shown, it is embodiment 1 of the present invention. The specific scheme of this embodiment is: a large burner for a rotary kiln, comprising a furnace tube 10, the furnace tube 10 is fixedly arranged on a mobile cart 25, an air intake pipe 11 is arranged in the furnace tube 10, a regulating valve 22 is connected to the air intake pipe 11, and a metal hose 23 is arranged at the air intake end of the air intake pipe 11;

[0041] Along the gas inlet direction, a ball valve 26, a flow meter 27, a pressure gauge 28, a cut-off valve 29, and a relief valve 30 are sequentially arranged at the gas inlet front end of the metal hose 23, and an air inlet pipe 12 is arranged on the furnace tube 10 in communication, wherein the gas is introduced into the air inlet pipe 11, and the air is introduced into the air inlet pipe 12, and the gas is mixed in the furnace tube 10 and then ignited and burned;

[0042] Specifically, an air supply pipe 13 is sleeved on the outer side of the air inlet pipe 11, and the air supply pipe 13 is arranged inside the furnace tube 10. There is a gap between the air supply pipe 13 and the air inlet pipe 11. The air introduced from the air inlet pipe 12 will pass through the gap between the air supply pipe 13 and the air inlet pipe 11, and enter the air supply pipe 13 to be premixed with the gas. In this way, the air and the gas can be mixed in advance, reducing the obstruction of the air and the gas due to the long transportation distance, improving the mixing effect of the premixing, and making the combustion efficiency higher.

[0043] A guide pipe 15 is provided at the end of the air supply pipe 13, and the guide pipe 15 can divert the introduced air, thereby achieving a multi-stage air supply effect for the gas in the combustion process. An igniter 16 is provided on the guide pipe 15, and the igniter 16 is used to ignite the gas for combustion.

[0044] As a preferred embodiment of the above embodiment, a plurality of spirally arranged first flow guides 14 are provided on the surface of the outlet end of the air inlet pipe 11. Figure 2 A plurality of second guide members 17 that can be screwed in and out with the first guide member 14 are arranged on the inner side wall of the air inlet end of the air supply pipe 13. The first guide member 14 and the second guide member 17 are both located in the gap between the air supply pipe 13 and the air inlet pipe 11. The first guide member 14 and the second guide member 17 are both provided with spiral guide plates. When air enters the gap between the air supply pipe 13 and the air inlet pipe 11, it can become a spiral vortex under the guidance of the first guide member 14 and the second guide member 17, so that a more uniform mixing can be achieved when mixing with the fuel gas.

[0045] As a preferred embodiment of the above-mentioned embodiment, an inwardly contracted constriction 131 is provided on one end of the air supply pipe 13 where combustion occurs, and a plurality of through holes 132 penetrating inside and outside are provided on the side close to the constriction 131. The through holes 132 can diffuse the gas input into the air supply pipe 13 to the surroundings, so that it can be mixed again with the air introduced from the surroundings; a plurality of first swirl plates 133 are provided on the inner wall of the air supply pipe 13 at one end of the combustion port, and the first swirl plates 133 can exert a swirl effect on the gas. A swirler 18 is also provided between the guide pipe 15 and the air supply pipe 13, and the swirler 18 mainly swirls the air, so that the ejected air and gas can be effectively and evenly mixed, thereby improving the combustion effect.

[0046] A diverter 19 is also provided in the guide pipe 15. The diverter 19 is arranged toward the side of the air supply pipe 13. The diverter 19 includes a plurality of guide plates 192 fixed to the inner wall of the igniter 16. The plurality of guide plates 192 extend toward the middle and are fixed to each other, and a guide hole 191 is provided at the middle position where they are fixed to each other. The gas ejected from the air supply pipe 13 will first be divided into an inner and outer layer under the action of the diverter 19. The inner layer passes through the guide hole 191 to become a direct current, and the outer layer will become a swirl under the action of the swirl of the guide plate 192. The outer swirl rotates around the center in a direct current, so that the flame that is finally ignited can form an olive leaf shape, so as to have better rigidity and higher combustion efficiency.

[0047] like Figure 3 As shown, the guide tube 15 is provided with a contraction section 151, which is close to the combustion port of the air supply tube 13. The contraction section 151 is provided with a penetrating air outlet 152, and the air outlet 152 faces the diverter 19. The guide tube 15 diverts the air into an inner and outer layer. The air in the outer layer has a low temperature when it does not participate in the combustion, which cools the guide tube 15 and the furnace tube 10. When it passes through the air outlet 152 and sprays onto the diverter 19, it can cool the diverter 19. The diverter 19 needs to be made of refractory material.

[0048] The furnace tube 10 is provided with a plurality of first return air holes 101 penetrating inside and outside. An isolating member 20 covering the first return air holes 101 is fixedly provided on the inner wall of the furnace tube 10, and the windward side of the isolating member 20 is an inclined surface fixedly in contact with the furnace tube 10. The first return air holes 101 can allow the air outside the furnace tube 10 and part of the flue gas to be introduced into the furnace tube 10. This is mainly determined by the inherent properties of fluid movement, that is, the flow velocity in the furnace tube 10 is high, and the air and flue gas outside the furnace tube 10 will automatically flow back into the box furnace tube 10. Since the furnace tube 10 is extended into the interior of the rotary kiln for heating, the temperature of the air and flue gas outside the furnace tube 10 is relatively high. When the air and flue gas flow back into the furnace tube 10 to participate in combustion, the air can be preheated. Example

[0049] This embodiment is a further improvement of the solution of embodiment 1. Figure 4-7As shown, the difference between this embodiment and Example 1 is that an extension furnace tube 21 is sleeved on the end of the furnace tube 10, and the end of the extension furnace tube 21 and the furnace tube 10 are slidably arranged with each other, and a gap is arranged between the extension furnace tube 21 and the furnace tube 10, and a second swirl sheet 215 is fixedly arranged between the extension furnace tube 21 and the guide tube 15, and the second swirl sheet 215 swirls the stratified air; an inwardly contracted necking section 211 is arranged on the end of the extension furnace tube 21 located at the combustion end, and the expansion section 212 is connected to the necking section 211, and the necking section 211 has the effect of converging the stratified air to the middle, so that the air flows to the middle to participate in the combustion, and the expansion section 212 is mainly for allowing the flame to spread outward after combustion.

[0050] Refer to the attached Figure 5 The extended furnace tube 21 is also provided with a plurality of penetrating second return air holes 213, and a wind shield 214 is also provided at the side of the second return air hole 213. The wind shield 214 and the extended furnace tube 21 are an integral structure. Specifically, the wind shield 214 is cut into shape and then bent outward to form the second return air hole 213. The wind shield 214 can block the speed of the return air so that the outside air can normally flow back into the furnace tube 10 through the second return air hole 213.

[0051] like Figure 4 , 6 7. A pull rod 24 is provided at the end of the air supply pipe 13. Specifically, the pull rod 24 and the air supply pipe 13 are rotatably arranged with each other, and can pull the air supply pipe 13 to reciprocate linearly. After the pull rod 24 passes through the furnace tube 10, it is connected to a driving source that drives it to slide along the axial direction of the air supply pipe 13. The driving source can be selected as needed, such as a cylinder, an electric push rod, etc. The structure of the driving source is not specifically drawn in this embodiment.

[0052] The end of the air supply pipe 13 is also provided with an adjustment component for controlling the air volume, and the adjustment component is used to adjust the premixed air volume, such as Figure 6As shown, it includes a gear 34 fixedly arranged on the pull rod 24, a movable ring 31 is threadedly connected to the end of the air supply pipe 13, the outer ring of the movable ring 31 and the gear 34 are meshed with each other through gear transmission, and a plurality of baffles 32 are hinged on the end surface of the movable ring 31, and the baffles 32 and the movable ring 31 are connected by torsion springs, and the torsion springs drive the baffles 32 to gather toward the middle of the air inlet pipe 11, and a limiting ring 33 for limiting the range of movement of the movable ring 31 is also provided on the pull rod 24; in the specific process of adjusting the air volume, by rotating the pull rod 24, the movable ring 31 can be driven to rotate on the air supply pipe 13, thereby changing the position of the movable ring 31 on the air supply pipe 13 When the air volume needs to be increased, the movable circle 31 is adjusted away from the end of the air supply pipe 13, so that the end of the air supply pipe 13 can push the baffle 32 outward, the air inlet of the air supply pipe 13 is increased, and the wind can enter the air supply pipe 13. When the air volume needs to be reduced, the movable circle 31 is adjusted close to the end of the air supply pipe 13. Under the action of the torsion spring, the space entering the air supply pipe 13 is gradually reduced, and the air volume is gradually reduced. In addition, for the problem of connecting the pull rod 24 to the driving source and controlling its rotation, it is only necessary to use a bearing between the pull rod 24 and the output shaft of the driving source, and the rotation drive of the pull rod 24 can be driven by a long gear.

[0053] It should be noted that, in this article, the terms include, contain or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. Specific examples are used in this article to illustrate the principle and implementation of the technical solution of the present invention. The above examples are only used to help understand the method of the present invention and its core idea. The above is only a preferred implementation of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements, modifications or changes can be made, and the above technical features can also be combined in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the invention to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A large burner for a rotary kiln, characterized in that: The furnace tube (10) comprises an air inlet pipe (11) arranged inside the furnace tube (10), and an air inlet pipe (12) is arranged on the furnace tube (10) in communication, an air supply pipe (13) is sleeved on the outer side of the air inlet pipe (11), a gap is provided between the air supply pipe (13) and the air inlet pipe (11), and air introduced from the air inlet pipe (12) passes through the gap between the air supply pipe (13) and the air inlet pipe (11) and enters the air supply pipe (13) to be premixed with the fuel gas; A flow guide pipe (15) is provided at the end of the air supply pipe (13), and an igniter (16) is provided on the flow guide pipe (15); A flow divider (19) is further provided in the flow guide pipe (15). The flow divider (19) is provided toward one side of the air supply pipe (13). The flow divider (19) includes a plurality of flow guide plates (192) fixed to the inner wall of the igniter (16). The plurality of flow guide plates (192) extend toward the middle and are fixed to each other. A flow guide hole (191) is provided at a middle position where the plurality of flow guide plates (192) are fixed to each other. The guide pipe (15) is provided with a contraction section (151), the contraction section (151) is close to the combustion port of the air supply pipe (13), and the contraction section (151) is provided with an air outlet (152) extending therethrough, the air outlet (152) faces the diverter (19); The end of the furnace tube (10) is sleeved with an extension furnace tube (21), the end of the extension furnace tube (21) and the furnace tube (10) are slidably arranged with each other, a gap is arranged between the extension furnace tube (21) and the furnace tube (10), and a second swirl sheet (215) is fixedly arranged between the extension furnace tube (21) and the guide tube (15); An inwardly contracted necking section (211) is provided on the end of the extended furnace tube (21) located at the combustion position, and the necking section (211) is connected to the expanding section (212).

2. A large burner for a rotary kiln according to claim 1, characterized in that: A plurality of spirally arranged first flow guide members (14) are provided on the surface of an outlet end of the air inlet pipe (11), and a plurality of second flow guide members (17) that can be screwed into and out of the first flow guide members (14) are provided on the inner side wall of an air inlet end of the air supply pipe (13). The first flow guide members (14) and the second flow guide members (17) are both located in the gap between the air supply pipe (13) and the air inlet pipe (11).

3. A large burner for a rotary kiln according to claim 1, characterized in that: An inwardly contracted opening (131) is provided at one end of the air supply pipe (13) for combustion, and a plurality of through holes (132) penetrating inside and outside are provided on one side close to the contracted opening (131); A plurality of first swirl sheets (133) are arranged on the inner wall of the air supply pipe (13) at one end of the burner port, and a swirler (18) is also arranged between the flow guide pipe (15) and the air supply pipe (13).

4. A large burner for a rotary kiln according to claim 1, characterized in that: The extended furnace tube (21) is also provided with a plurality of penetrating second air return holes (213), and a wind shield (214) is also provided on the side of the second air return hole (213).

5. A large burner for a rotary kiln according to claim 1, characterized in that: A pull rod (24) is provided at the end of the air supply pipe (13); the pull rod (24) passes through the furnace pipe (10) and is connected to a driving source that drives it to slide along the axial direction of the air supply pipe (13); The end of the air supply pipe (13) is also provided with an adjustment component for controlling the air volume.

6. A large burner for a rotary kiln according to any one of claims 1 to 5, characterized in that: The furnace pipe (10) is fixedly arranged on the mobile cart (25), the air intake pipe (11) is connected to a regulating valve (22), and the air intake end of the air intake pipe (11) is connected to a metal hose (23); Along the gas inlet direction, a ball valve (26), a flow meter (27), a pressure gauge (28), a cut-off valve (29), and a relief valve (30) are sequentially arranged at the gas inlet front end of the metal hose (23) and are connected to the metal hose (23).

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