Low-nitrogen-oxygen combustion equipment

Abstract

The invention relates to the technical field of combustion equipment, in particular to low-nitrogen-oxygen combustion equipment which comprises a combustion chamber body and a central spray pipe, the combustion chamber body comprises a front cone and a rear cone, the front cone and the rear cone are both of a shell structure, and the larger ends of the front cone and the rear cone are oppositely and integrally arranged; a circulating combustion chamber is formed in the front cone and the rear cone, the end, away from the rear cone, of the front cone is used for being connected with a furnace body, a center spray pipe is inserted into the center of the end, away from the front cone, of the rear cone, and a backflow cap is arranged at the end, located in the combustion chamber, of the center spray pipe and located in the rear cone. The interior of the center spray pipe is used for introducing flowing pulverized coal, an air inlet pipe is arranged at the end, away from the interior of the front cone, of the rear cone, and the air inlet pipe is used for introducing air flowing along the inner wall of the rear cone. The present application has the effect of controlling the generation of nitrogen oxides from the source.

Description

Technical Field

[0001] The present application relates to the technical field of combustion equipment, and in particular to low nitrogen and oxygen combustion equipment. Background Art

[0002] The combustion equipment currently used in pulverized coal boilers uses pulverized coal as fuel, which is then mixed with air and sprayed into the boiler for combustion. During the combustion of pulverized coal, fuel-type nitrogen oxides and thermal-type nitrogen oxides will be produced. Currently, the control of fuel-type nitrogen oxides in pulverized coal combustion equipment is mainly to control the temperature, and the control of thermal-type nitrogen oxides is mainly to control the excess air coefficient, so as to keep the main combustion zone lacking oxygen and burning in a reducing atmosphere.

[0003] At present, the technologies for reducing nitrogen oxides through combustion equipment mainly include staged combustion, flue gas recirculation or flue gas internal circulation. Among them, the authorization announcement number is CN 206724175U, the patent name is a staged gas low-nitrogen burner, which adopts staged combustion, the application publication number is patent CN106500094A, the name is a medium-high temperature flue gas circulation low-nitrogen staged burner and process, which adopts flue gas recirculation; the authorization announcement number is CN206001467U, the patent name is a flue gas internal circulation low-nitrogen gas burner, which adopts flue gas internal circulation. The above combustion technologies cannot reduce the generation of nitrogen oxides from the source, and the effect on reducing nitrogen oxide emissions is not significant enough, and cannot achieve a good energy-saving and emission reduction effect. Summary of the invention

[0004] In order to control the generation of nitrogen oxides from the source, the present application provides a low nitrogen and oxygen combustion device.

[0005] The present application provides a low nitrogen and oxygen combustion device, which adopts the following technical solution: A low nitrogen and oxygen combustion device comprises a combustion chamber body and a central nozzle, wherein the combustion chamber body comprises a front cone and a rear cone, wherein the front cone and the rear cone are both shell structures and the larger ends of the front cone and the rear cone are relatively integrally arranged, wherein a circulating combustion chamber is formed inside the front cone and the rear cone, wherein the end of the front cone away from the rear cone is used to connect to a furnace body, wherein the center of the end of the rear cone away from the front cone is inserted into the central nozzle, wherein a reflux cap is provided at one end of the central nozzle located within the combustion chamber body, wherein the reflux cap is located within the rear cone, wherein the interior of the central nozzle is used to introduce flowing pulverized coal, wherein an air inlet pipe is provided at one end of the rear cone away from the front cone, wherein the air inlet pipe is used to introduce air flowing along the inner wall of the rear cone.

[0006] By adopting the above technical scheme, when in use, the flowing coal powder in the central nozzle will flow to one end of the reflux cap, flow in the opposite direction under the action of the reflux cap, and then be dispersed outwards through the action of the circulating combustion chamber and mixed with the air flowing along the inner wall of the rear cone introduced into the air inlet pipe, so that the coal powder can fully contact the air and then flow in the direction of the front cone and pre-combust in the front cone. Part of the coal powder pre-combusted in the front cone will be affected by the airflow and flow back to the circulating combustion chamber again to contact the coal powder just flowing out of the central nozzle, so as to preheat the coal powder. Thus, the coal powder is preheated first and then pre-combusted after sufficient mixing, so that the combustion of the coal powder is relatively stable, thereby controlling the generation of nitrogen oxides from the source.

[0007] Preferably, an adjustment device is provided in the rear cone, and the adjustment device includes a fixed body and a movable body, the fixed body is fixed on the rear cone, the movable body is slidably connected to the central nozzle, the connection between the fixed body and the movable body is sealed and cooperates with the inner wall of the rear cone to form an air inlet cavity, and the air inlet pipe is connected to the air inlet cavity.

[0008] By adopting the above technical solution, the fixed body is fixed on the rear cone, and the movable body is slidably connected to the central nozzle. When the movable body moves along the central nozzle, the volume of the circulating combustion chamber formed between the movable body and the front cone changes. Therefore, when the amount of injected coal powder is different, the volume of the circulating combustion chamber can be adjusted to adjust the amount of circulating coal powder, so that the preheating and pre-combustion of the coal powder can be controlled.

[0009] Preferably, the movable body is configured to be conical and the larger end opening of the movable body faces the front cone, and the movable body is connected to a driving device for driving the movable body to move along the length direction of the central nozzle.

[0010] By adopting the above technical solution, the movable body is configured as a cone, and the end of the movable body with a larger opening faces the front cone, so that the circulating airflow formed on the inner wall of the movable body can flow along the inner wall of the movable body to mix with the air entering from the air inlet pipe.

[0011] Preferably, the fixed body includes a mounting ring and an elastic sheet, the mounting ring is fixed on the inner wall of the rear cone, a plurality of elastic sheets are evenly arranged along the circumference of the mounting ring, and the elastic sheet is inclined toward the direction of the center tube away from one end of the mounting ring and abuts against the outer wall of the movable body, and two adjacent elastic sheets are overlapped.

[0012] By adopting the above technical solution, the mounting ring is fixed on the inner wall of the rear cone, one end of the elastic sheet is fixed on the mounting ring, and the other end is a free end against the outer wall of the movable body. When the movable body moves, the elastic sheet rotates away from one end of the mounting ring, thereby maintaining the airtight contact between the elastic sheet and the movable body.

[0013] Preferably, the driving device includes a driving motor and a driving screw. The driving motor is a servo motor or a stepping motor. The driving motor is fixed on the central nozzle. The driving screw is arranged parallel to the central nozzle. The driving screw is coaxially connected to the output shaft of the driving motor. The movable body is connected to a movable frame that passes through the rear cone, and the movable frame is threadedly connected to the driving screw.

[0014] By adopting the above technical solution, the driving motor is used to drive the driving screw to rotate. When the driving screw is threadedly connected to the moving frame, the driving screw can drive the moving frame, thereby moving the movable body through the moving frame, so that the movable body is automatically controlled.

[0015] Preferably, the cross section of the mounting ring is Z-shaped, a through hole is opened in the middle of the mounting ring, one side of the mounting ring is fixed to the inner wall of the rear cone, and the other side is used to fix the elastic sheet.

[0016] By adopting the above technical solution, the cross-section of the mounting ring is Z-shaped, so that the mounting position of the elastic sheet and the inner wall of the rear cone can be ventilated and flow out from the through hole, so that the coal powder flowing from the inside of the elastic sheet can meet and mix in time.

[0017] Preferably, a feeding device is connected to the central nozzle, and the feeding device includes a material pipe, a spiral conveying rod and a feeding motor. The material pipe is vertically arranged and the upper end of the material pipe is connected to the central nozzle. The spiral conveying rod cooperates with the material pipe to convey coal powder. The feeding motor is used to drive the spiral conveying rod to rotate, and one end of the central nozzle is used to introduce primary air.

[0018] By adopting the above technical solution, the material pipe on the central nozzle is arranged vertically, so that when the spiral conveying rod conveys the coal powder, the coal powder can be conveyed according to the required amount, and the coal powder conveyed into the central nozzle is conveyed by the action of the airflow, so that the coal powder can be evenly distributed, thereby improving the stability of combustion.

[0019] Preferably, a spiral blade is provided inside the central nozzle, the spiral blade is fixed on the central nozzle, and the center line of the spiral blade coincides with the center line of the central nozzle, the length of the spiral blade is smaller than the length of the central nozzle and the spiral blade is installed at the connection between the material pipe and the central nozzle.

[0020] By adopting the above technical solution, the spiral blades are fixed in the central nozzle. When the air flows through the central nozzle, the coal powder in the central nozzle will rotate on the middle spiral blades under the action of the air flow, so that the air flow can carry the coal powder to avoid uneven distribution of the coal powder on the lower side of the central nozzle. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1is a cross-sectional view of the overall structure in an embodiment of the present application; Figure 2 is a diagram of the installation structure of the reflux cap in the embodiment of the present application; Figure 3 It is a schematic diagram of the positions of the fixed body and the movable body in the embodiment of the present application.

[0022] Explanation of the reference numerals: 1. combustion chamber body; 11. front cone; 12. rear cone; 13. circulating combustion chamber; 2. central nozzle; 21. return cap; 22. spiral blade; 23. fixing rod; 3. adjusting device; 31. fixing body; 311. mounting ring; 312. elastic sheet; 32. movable body; 321. movable frame; 4. air inlet cavity; 5. air inlet pipe; 51. branch pipe; 6. through hole; 7. feeding device; 71. material pipe; 72. spiral conveying rod; 73. feeding motor; 8. driving device; 81. driving motor; 82. driving screw. DETAILED DESCRIPTION

[0023] The following is combined with Figure 1-3 This application is described in further detail.

[0024] The present application embodiment discloses a low nitrogen and oxygen combustion device, referring to Figure 1, including a combustion chamber body 1 and a central nozzle 2, the combustion chamber body 1 includes a front cone 11 and a rear cone 12, one end of the front cone 11 is open for connecting to the furnace body, one end of the rear cone 12 is connected to the end of the front cone 11 away from the furnace body, and the diameters of the connection between the front cone 11 and the rear cone 12 are equal, the diameter of the end where the front cone 11 is connected to the rear cone 12 is larger than the diameter of the end where the front cone 11 is connected to the furnace body, the diameter of the end where the rear cone 12 is connected to the front cone 11 is larger than the diameter of the other end of the rear cone 12, the center lines of the front cone 11 and the rear cone 12 coincide, the interiors of the front cone 11 and the rear cone 12 are hollow structures to form a circulating combustion chamber 13, the pulverized coal in the front cone 11 will undergo preliminary combustion, which can improve the stability of the pulverized coal combustion. At the same time, due to the temperature rise caused by the pre-combustion of the coal powder in the front cone 11, the coal powder that has just entered the circulating combustion chamber 13 can be heated as the airflow circulates in the circulating combustion chamber 13, so that the coal powder is first preheated in the circulating combustion chamber 13, and then pre-combusted, and finally burned in the process of being ejected from the front cone 11, so that the combustion of the coal powder is relatively complete and stable, thereby reducing the nitrogen oxides formed by unstable combustion. The center line of the central nozzle 2 is arranged to coincide with the center of the combustion chamber body 1, and the central nozzle 2 is inserted into the circulating combustion chamber 13 from one end of the rear cone 12 away from the front cone 11, and the end of the central nozzle 2 does not exceed the plane where the front cone 11 and the rear cone 12 are spliced. A reflux cap 21 is arranged at one end of the central nozzle 2 located in the combustion chamber body 1, and the reflux cap 21 is used to make the airflow ejected by the central nozzle 2 toward the front cone 11 turn 180 degrees and then move into the rear cone 12, so that the airflow circulates backward.

[0025] An adjusting device 3 is provided at the rear cone 12, and the adjusting device 3 is used to adjust the volume in the circulating combustion chamber 13. When the adjusting device 3 adjusts the volume of the circulating combustion chamber 13, the axial length of the circulating combustion chamber 13 can be reduced to adjust the circulation path of the coal powder sprayed from the central nozzle 2 in the circulating combustion chamber 13. Since the coal powder in the circulating combustion chamber 13 is subject to different heat transported to the furnace body, the amount of coal powder will also change. When the amount of coal powder decreases, the volume of the circulating fuel chamber is reduced to shorten the circulation path, and then the amount of airflow distributed to the furnace body and the reflux is adjusted to a suitable range to prevent the reflux from being too large, resulting in too long a time in the circulating combustion chamber 13, causing the pre-combustion temperature to be too high, causing the temperature of the combustion chamber body 1 to rise, and affecting the service life.

[0026] The adjusting device 3 includes a fixed body 31 and a movable body 32. The fixed body 31 is fixed on the inner wall of the rear cone 12. The movable body 32 is slidably connected to the central nozzle 2 along the length direction of the central nozzle 2. The connection between the movable body 32 and the fixed body 31 adopts an abutment connection method, so that the movable body 32 and the fixed body 31 can move relative to each other, and the connection between the movable body 32 and the fixed body 31 is closed. The movable body 32 and the fixed body 31 form an air inlet chamber 4 between the inner wall of the rear cone 12 and the inner wall of the rear cone 12. An air inlet pipe 5 is fixedly provided at the end of the rear cone 12 away from the front cone 11. The air inlet pipe 5 is connected to the rear cone 12 through a plurality of branch pipes 51. The plurality of branch pipes 51 are evenly distributed around the central nozzle 2, so that the gas entering the air inlet cavity 4 through the air inlet pipe 5 moves along the inner wall of the rear cone 12 toward the front cone 11, and enters the circulating combustion chamber 13 through a through hole 6 provided on the fixed body 31, and is mixed with the coal powder flowing through the inner wall of the regulating device 3 at the position entering the circulating combustion chamber 13. Primary air enters at one end of the central nozzle 2 located outside the rear cone 12, and the primary air is used to make the coal powder flow and to make the coal powder be sprayed into the circulating combustion chamber 13 relatively evenly along the central nozzle 2. When the coal powder forms an airflow state and is then mixed with the secondary air entering through the air inlet pipe 5, the coal powder can be mixed with the air faster and more fully, so that the coal powder can be carried out synchronously in the subsequent pre-combustion and combustion processes, thereby improving the stability of combustion.

[0027] A feeding device 7 is provided at one end of the central nozzle 2 outside the rear cone 12. The feeding device 7 includes a material pipe 71, a screw conveying rod 72 and a feeding motor 73. The material pipe 71 is vertically arranged and the upper end of the material pipe 71 is fixed on the side wall of the central nozzle 2. The material pipe 71 is connected to the central nozzle 2. The screw conveying rod 72 is fitted in the material pipe 71. The lower end of the screw conveying rod 72 is coaxially fixedly connected with the output shaft of the feeding motor 73. The feeding motor 73 is used to drive the screw conveying rod 72 to rotate, so that the screw conveying rod 72 cooperates with the material pipe 71 to convey the coal powder into the central nozzle 2. The feeding motor 73 adopts a servo motor or a stepping motor. The rotation speed of the screw conveying rod 72 is controlled by the feeding motor 73, so that the screw conveying rod 72 can control the amount of coal powder conveyed to the central nozzle 2. Since there is primary air flowing in the central nozzle 2, the primary air drives the coal powder entering the central nozzle 2 to flow. A spiral blade 22 is fixedly provided on the inner wall of the central nozzle 2, and the center line of the spiral blade 22 coincides with the center line of the central nozzle 2, and the length of the spiral blade 22 is smaller than the length of the central nozzle 2, and the spiral blade 22 is located at the position where the central nozzle 2 is connected to the feeding device 7, so that the spiral blade 22 first spirally conveys the coal powder to fully mix the coal powder with the primary air, and then moves to the position of the reflux cap 21, so that the airflow at the reflux cap 21 is relatively stable and flows out evenly from a circle of the reflux cap 21.

[0028] refer to Figure 2 The return cap 21 is overall configured to be a hollow truncated cone with a smaller end open. One end of the central nozzle 2 is inserted into the return cap 21 from the center position of the opening of the return cap 21 and is spaced apart from the bottom of the return cap 21. A plurality of fixing rods 23 are provided on the peripheral wall of the central nozzle 2. The plurality of fixing rods 23 are spaced apart. The fixing rods 23 are fixedly connected to the central nozzle 2 and the return cap 21 to fix the return cap 21 on the central nozzle 2. The openings of the central nozzle 2 and the return cap 21 are spaced apart so that the airflow of the mixed coal powder enters the rear cone 12 backward from the opening of the return cap 21.

[0029] refer to Figure 3 The movable body 32 is configured as a cone-shaped structure as a whole, and the larger end of the cone of the movable body 32 is arranged toward the front cone 11, and the movable body 32 is arranged toward the opening on one side of the front cone 11, so that the circulating gas can enter the movable body 32, and move outwardly through the movable body 32 to facilitate the encounter and mixing with the secondary air entering the circulating combustion chamber 13. The movable body 32 is sleeved on the central nozzle 2, and a driving device 8 is arranged outside the rear cone 12. A movable frame 321 is connected to the movable body 32, and the driving device 8 is used to drive the movable frame 321 to move the movable body 32 along the length direction of the central nozzle 2. The movable frame 321 penetrates the rear cone 12 and is fixedly connected to the movable body 32, and the movable frame 321 is slidably connected to the rear cone 12, and a part of the movable frame 321 is exposed from the rear cone 12. The driving device 8 includes a driving motor 81 and a driving screw 82. The driving screw 82 is parallel to the central nozzle 2. The driving screw 82 is coaxially fixed on the output shaft of the driving motor 81. The driving motor 81 is fixed on the central nozzle 2. The driving motor 81 adopts a servo motor or a stepping motor. The driving motor 81 drives the driving screw 82 to rotate. The driving screw 82 is threadedly connected to the part of the movable frame 321 located outside the rear cone 12, so that the movable frame 321 moves under the action of the driving screw 82, so that the position of the movable body 32 can be adjusted, and then the volume of the movable circulating combustion chamber 13 can be adjusted.

[0030] The fixed body 31 includes a mounting ring 311 and an elastic sheet 312. The mounting ring 311 can be fixed to the inner wall of the rear cone 12 by rivets. The cross-section of the mounting ring 311 is set to be Z-shaped. The middle position of the Z-shaped structure of the mounting ring 311 is used to open a through hole 6, so that the secondary air can enter the circulating combustion chamber 13 from the through hole 6. A plurality of through holes 6 are evenly arranged along the circumference of the mounting ring 311. The outer side of the mounting ring 311 is fixed to the rear cone 12. The inner side of the mounting ring 311 extends in a direction away from the front cone 11 and is used to fix the elastic sheet 312. One end of the elastic sheet 312 is connected to the mounting ring 311 by rivets, and the other end is a free end. A plurality of elastic sheets 312 are evenly distributed along the circumference of the mounting ring 311, and the arrangement direction of the elastic sheets 312 is that the free end of the elastic sheet 312 approaches the direction of the central nozzle 2 and is at the same distance from the central nozzle 2. The ends of the plurality of elastic sheets away from the mounting ring 311 are sealed in a stacked manner. When the movable body 32 increases the volume of the circulating combustion chamber 13, the free end of the elastic sheet 312 is abutted by the movable body 32, causing the elastic sheet 312 to open in a direction away from the central nozzle 2. In the process of adjusting the volume of the circulating combustion chamber 13, the separation of the air inlet chamber 4 and the circulating combustion chamber 13 is ensured.

[0031] The working process of this embodiment: First, the coal powder enters the side of the central nozzle 2 through the feeding device 7. At the same time, the primary air in the central nozzle 2 causes the coal powder to flow into the position of the reflux cap 21. The reflux cap 21 turns the coal powder 180 degrees and enters the rear cone 12. It moves outward at the position of the movable body 32, so that the secondary air entering from the air inlet chamber 4 is mixed with the coal powder, and then enters the front cone 11 for pre-combustion. The partially pre-combusted coal powder is then circulated to preheat the coal powder that has just entered the circulating combustion chamber 13. When the volume of the circulating combustion chamber 13 needs to be adjusted, the movable body 32 moves along the length direction of the central nozzle 2 to adjust the circulation path of the coal powder airflow.

[0032] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A low nitrogen and oxygen combustion equipment, characterized in that: The invention comprises a combustion chamber body (1) and a central nozzle (2), wherein the combustion chamber body (1) comprises a front cone (11) and a rear cone (12), wherein the front cone (11) and the rear cone (12) are both shell structures and the larger ends of the front cone (11) and the rear cone (12) are arranged integrally with each other, wherein a circulating combustion chamber (13) is formed inside the front cone (11) and the rear cone (12), wherein the end of the front cone (11) away from the rear cone (12) is used for connecting to a furnace body, and the rear cone (12) is used for connecting to a furnace body. ) is inserted into the center of one end away from the front cone (11), and the end of the central nozzle (2) located in the combustion chamber body (1) is provided with a return cap (21), and the return cap (21) is located in the rear cone (12). The central nozzle (2) is used to introduce flowing coal powder, and the end of the rear cone (12) away from the front cone (11) is provided with an air inlet pipe (5), and the air inlet pipe (5) is used to introduce air flowing along the inner wall of the rear cone (12).

2. A low nitrogen and oxygen combustion equipment according to claim 1, characterized in that: An adjusting device (3) is arranged inside the rear cone (12), and the adjusting device (3) comprises a fixed body (31) and a movable body (32), wherein the fixed body (31) is fixed to the rear cone (12), and the movable body (32) is slidably connected to the central nozzle (2), and the connection between the fixed body (31) and the movable body (32) is sealed and cooperates with the inner wall of the rear cone (12) to form an air inlet cavity (4), and the air inlet pipe (5) is connected to the air inlet cavity (4).

3. A low nitrogen and oxygen combustion equipment according to claim 2, characterized in that: The movable body (32) is arranged in a cone shape, and the larger end opening of the movable body (32) faces the front cone (11). The movable body (32) is connected to a driving device (8) for driving the movable body (32) to move along the length direction of the central nozzle (2).

4. A low nitrogen and oxygen combustion equipment according to claim 3, characterized in that: The fixed body (31) comprises a mounting ring (311) and an elastic sheet (312); the mounting ring (311) is fixed on the inner wall of the rear cone (12); a plurality of elastic sheets (312) are evenly arranged along the circumference of the mounting ring (311); one end of the elastic sheet (312) away from the mounting ring (311) is inclined in the direction of the central tube and abuts against the outer wall of the movable body (32); two adjacent elastic sheets (312) are arranged to overlap.

5. A low nitrogen and oxygen combustion equipment according to claim 3, characterized in that: The driving device (8) comprises a driving motor (81) and a driving screw (82). The driving motor (81) is a servo motor or a stepping motor. The driving motor (81) is fixed to the central nozzle (2). The driving screw (82) is arranged parallel to the central nozzle (2). The driving screw (82) is coaxially connected to the output shaft of the driving motor (81). The movable body (32) is connected to a moving frame (321) that passes through the rear cone (12). The moving frame (321) is threadedly connected to the driving screw (82).

6. A low nitrogen and oxygen combustion equipment according to claim 4, characterized in that: The cross section of the mounting ring (311) is Z-shaped, a through hole (6) is provided in the middle of the mounting ring (311), one side of the mounting ring (311) is fixed to the inner wall of the rear cone (12), and the other side is used to fix the elastic sheet (312).

7. A low nitrogen and oxygen combustion equipment according to claim 1, characterized in that: The central nozzle (2) is connected to a feeding device (7), the feeding device (7) comprising a material pipe (71), a screw conveying rod (72) and a feeding motor (73), the material pipe (71) being arranged vertically and the upper end of the material pipe (71) being connected to the central nozzle (2), the screw conveying rod (72) and the material pipe (71) cooperating to convey coal powder, the feeding motor (73) being used to drive the screw conveying rod (72) to rotate, and one end of the central nozzle (2) being used to introduce primary air.

8. A low nitrogen and oxygen combustion equipment according to claim 7, characterized in that: A spiral blade (22) is arranged inside the central nozzle (2). The spiral blade (22) is fixed on the central nozzle (2), and the center line of the spiral blade (22) coincides with the center line of the central nozzle (2). The length of the spiral blade (22) is less than the length of the central nozzle (2), and the spiral blade (22) is installed at the connection between the material pipe (71) and the central nozzle (2).

Images