Low-nitrogen decomposing furnace
By dividing the decomposition furnace function into the main furnace part and the reduction part, and using the decomposition reaction of coal powder in high temperature and low oxygen environment, effective reduction and emission control of NOx are achieved, and the problem of difficult reduction of NOx emissions in existing SNCR technology is solved. , reducing ammonia water consumption and production costs.
Patent Information
- Application Number
- CN202421197600.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-29
- Publication Date
- 2025-02-11
- Estimated Expiration
- 2034-05-29
AI Technical Summary
The existing SNCR technology is difficult to further reduce NOx emissions, and the ammonia consumption is large, making it difficult to meet the ultra-low emission requirements.
Design a low-nitrogen decomposition furnace. By dividing the decomposition furnace function into the main furnace part and the reduction part, the coal powder decomposes the reducing gas under high temperature and low oxygen environment, reducing the NOx generated in the kiln to N2, reducing NOx emissions, and Optimize coal pulverized combustion to reduce ammonia water consumption.
It effectively reduces the NOx emission value at the end of the kiln and is stably controlled within 50mg, reduces the ammonia consumption, reduces the production and operation cost, and ensures the normal operation of clinker production.
Smart Images
Figure CN222460246U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of decomposition furnaces, in particular to a low-nitrogen decomposition furnace. Background Art
[0002] During the normal operation of the rotary kiln, the calcination temperature in the kiln will reach 1400-1480℃, under which a large amount of NOx will be produced. In addition, although the combustion temperature of the pulverized coal in the decomposition furnace is only 850-950℃, a small amount of NOx will also be produced, which will be directly discharged into the atmosphere through the chimney, causing environmental pollution.
[0003] As the requirements for environmental governance become increasingly stringent, the requirements for cement plant exhaust emissions are also getting higher and higher. Most companies use SNCR (non-selective catalytic reduction technology) to control NOx emissions, but the SNCR denitrification efficiency is only 80%. Not to mention the large amount of ammonia water consumption, it is difficult to control NOx within 50mg to meet ultra-low emission requirements. Summary of the invention
[0004] The utility model aims to provide a low-nitrogen decomposition furnace to solve the problem that it is difficult to further reduce NOx emissions in the existing SNCR technology and simultaneously reduce ammonia consumption.
[0005] To achieve the above purpose, the utility model adopts the following technical solution: a low-nitrogen decomposition furnace, comprising a furnace body, the furnace body comprising a main furnace part and a reduction part welded to the bottom of the main furnace part, an air delivery pipe is provided on the outer surface of the main furnace part near one end of the reduction part, and a pulverized coal pipe is provided on the outer side of the main furnace part.
[0006] The pulverized coal pipe includes a main powder pipe, a powder distribution pipe vertically arranged at one end of the main powder pipe, an upper ring powder pipe arranged at one end of the powder distribution pipe and surrounding the periphery of the main furnace part, and a lower ring powder pipe arranged at the other end of the powder distribution pipe and surrounding the periphery of the bottom end of the reduction part. The inner sides of the upper ring powder pipe and the lower ring powder pipe are both provided with a powder conveying pipe inserted into the furnace body;
[0007] Raw material pipes are provided on both sides of the furnace body, and the raw material pipes include a feed pipe, a decomposition pipe and a temperature control pipe arranged at one end of the feed pipe through a three-way joint. The other end of the decomposition pipe is inserted into the main furnace part, and the other end of the temperature control pipe is inserted into the reduction part.
[0008] This technology is to modify the original decomposition furnace structure, divide the decomposition furnace function into the main furnace part and the reduction part, and evenly input part of the pulverized coal into the reduction part from multiple directions through the lower ring powder pipe and the powder conveying pipe inside the lower ring powder pipe. By utilizing the principle that pulverized coal will decompose into reducing gases such as H2, CH4, and CO under a high temperature and low oxygen environment, the NOx produced in the kiln is reduced to N2, thereby reducing the concentration of NOx and reducing the N2 produced by the combustion of pulverized coal in the decomposition furnace. At the same time, it does not affect the normal operation of the kiln system, and can stably control the NOx emission value at the kiln tail within 50mg, so that the later ammonia consumption is not high and the production and operation cost is reduced. The carbonate decomposition is carried out in the main furnace part to ensure the normal operation of clinker production.
[0009] Optionally, the bottom end of the main furnace portion is welded to the reduction portion through a truncated cone sleeve, and the bottom end of the reduction portion is conical.
[0010] Optionally, the air supply duct includes a main air duct, a ring air duct arranged at the other end of the main air duct through a tee pipe and environmentally friendly to the periphery of the main furnace part, and a plurality of branch air ducts evenly arranged on the inner side of the ring air duct and inserted into the interior of the main furnace part, the branch air duct is inclined upward from the outside to the inside, and one end of the branch air duct away from the ring air duct is flush with the inner wall of the main furnace part.
[0011] The air duct is designed to be ring-shaped, and the hot air is input into the main furnace from different directions through multiple branch air ducts, which effectively ensures the uniformity of the hot air and can better mix the coal powder output from the upper ring powder pipe with the hot air, so that the coal powder can be fully burned.
[0012] Optionally, the main powder pipe and the powder distribution pipe are connected via a tee pipe, and a distribution plate is provided in the tee pipe.
[0013] The proportion of pulverized coal entering the main furnace section and the reduction section is controlled by the dividing plate, so that the generated CO can meet the demand for destocking as much as possible.
[0014] Optionally, the main powder pipe and the powder distribution pipe are connected via a tee, and an adjustable material distributor extending to the inside of the tee is provided outside the tee, and the adjustable material distributor includes an electric push rod rotatably mounted on the side wall of the main powder pipe at one end, an adjusting rod hinged at the movable end of the electric push rod, and a movable material distribution plate rotatably mounted inside the tee and with an axial rod extending out of the tee, and the movable material distribution plate is located on the axial rod outside the tee and is fixedly connected to the other end of the adjusting rod.
[0015] Through the above technology, the proportion of coal powder entering the main furnace section and the reduction section can be controlled more accurately.
[0016] Optionally, the upper ring powder pipe is located above the ring air duct, the powder conveying pipe inside the upper ring powder pipe is horizontal and located above the diversion air duct, and the powder conveying pipe inside the lower ring powder pipe is inclined upward from outside to inside.
[0017] The powder conveying pipe inside the upper ring powder pipe is located above the diversion air duct, which can effectively mix the pulverized coal input into the main furnace with the hot air below.
[0018] Optionally, the raw material pipe is connected to the furnace body in a downwardly inclined state from outside to inside, the end of the decomposition material pipe away from the feed pipe is located above the upper ring powder pipe, and the end of the temperature control material pipe away from the feed pipe is located above the lower ring powder pipe.
[0019] By adopting the above technical solution, the raw meal output from the decomposition pipe falls naturally under the action of gravity, while the hot air and coal powder below fly upward under the action of air. After the two meet, they can be fully mixed together, so that the decomposition rate of carbonate can reach the ideal state as much as possible.
[0020] Compared with the prior art, the beneficial effects of the utility model are:
[0021] 1. The decomposition furnace is divided into the main furnace part and the reduction part. Part of the pulverized coal is uniformly input into the reduction part from multiple directions through the lower ring powder pipe and the powder conveying pipe in the lower ring powder pipe. The principle that pulverized coal will decompose H2, CH4, CO and other reducing gases under high temperature and low oxygen environment is used to reduce the NOx generated in the kiln into N2, so as to reduce the concentration of NOx and reduce the N2 generated by the combustion of pulverized coal in the decomposition furnace. At the same time, it does not affect the normal operation of the kiln system, and the NOx emission value at the kiln tail can be stably controlled within 50mg, so that the later ammonia consumption is not high and the production and operation cost is reduced; 2. The lower ring powder pipe in the reduction part is arranged at the bottom of the reduction part cone, which can ensure that the reduction area in the reduction part is as large as possible, and can prevent the tail coal from falling into the smoke chamber, forming a high temperature or crust in the smoke chamber; 3. The raw meal output from the decomposition material pipe falls naturally under the action of gravity, while the hot air and pulverized coal below fly upward under the action of air. After the two meet, they can be fully mixed together, so that the decomposition rate of carbonate can reach the ideal state as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 This is a schematic diagram of the front structure of a low-nitrogen decomposition furnace of the utility model;
[0023] Figure 2 This is a schematic diagram of the structure of a low-nitrogen decomposition furnace from the rear side of the utility model;
[0024] Figure 3 This is a schematic diagram of the structure of a low-nitrogen decomposition furnace from the front side of the utility model;
[0025] Figure 4 This is a schematic diagram of a vertical cross-section structure of a low-nitrogen decomposition furnace of the utility model;
[0026] Figure 5 This is a schematic diagram of the cross-sectional structure of an adjustable material distributor of the utility model;
[0027] Figure 6 The utility model is a schematic diagram of the structure of an adjustable material distributor.
[0028] In the figure: 1. Main furnace section; 2. Reduction section; 3. Air delivery duct; 31. Main air duct; 32. Annular air duct; 33. Diverter air duct; 4. Pulverized coal pipe; 41. Main powder pipe; 42. Powder distribution pipe; 43. Upper annular powder pipe; 44. Lower annular powder pipe; 45. Powder delivery pipe; 5. Raw material pipe; 51. Feed pipe; 52. Decomposition material pipe; 53. Temperature control material pipe; 6. Adjustable distributor; 61. Electric push rod; 62. Adjustment rod; 63. Movable distributor plate. DETAILED DESCRIPTION
[0029] The following will be combined with the drawings in the utility model to clearly and completely describe the technical solution of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0030] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as "middle", "upper", "lower", "left", "right", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.
[0031] like Figure 1 —3, the specific scheme of the embodiment is as follows: a low-nitrogen decomposition furnace, including a furnace body, the furnace body includes a main furnace part 1 and a reduction part 2 welded to the bottom of the main furnace part 1, an air supply pipe 3 is provided on the outer surface of the main furnace part 1 near one end of the reduction part 2, and a coal powder pipe 4 is provided on the outer side of the main furnace part 1.
[0032] The pulverized coal pipe 4 includes a main powder pipe 41, a powder distribution pipe 42 vertically arranged at one end of the main powder pipe 41, an upper ring powder pipe 43 arranged at one end of the powder distribution pipe 42 and surrounding the periphery of the main furnace part 1, and a lower ring powder pipe 44 arranged at the other end of the powder distribution pipe 42 and surrounding the periphery of the bottom end of the reduction part 2. The inner sides of the upper ring powder pipe 43 and the lower ring powder pipe 44 are both provided with a powder conveying pipe 45 inserted into the furnace body;
[0033] Raw material pipes 5 are provided on both sides of the furnace body, and the raw material pipes 5 include a feed pipe 51, a decomposition pipe 52 arranged at one end of the feed pipe 51 through a three-way joint, and a temperature control pipe 53. The other end of the decomposition pipe 52 is inserted into the main furnace part 1, and the other end of the temperature control pipe 53 is inserted into the reduction part 2.
[0034] This technology is to modify the original decomposition furnace structure, divide the decomposition furnace function into the main furnace part 1 and the reduction part 2, and evenly input part of the coal powder into the reduction part 2 from multiple directions through the lower ring powder pipe 42 and the powder conveying pipe 45 in the lower ring powder pipe 42. The principle that coal powder will decompose into reducing gases such as H2, CH4, CO, etc. under a high temperature and low oxygen environment is used to reduce the NOx produced in the kiln into N2, thereby reducing the NOx concentration and reducing the N2 produced by the combustion of coal powder in the decomposition furnace. At the same time, it does not affect the normal operation of the kiln system, and can stably control the NOx emission value at the kiln tail to within 50mg, so that the later ammonia consumption is not high and the production and operation cost is reduced. The carbonate decomposition is carried out in the main furnace part 1 to ensure the normal operation of clinker production.
[0035] In addition, since the reduction zone requires a certain temperature, which is generally 950-1050° C., the higher the temperature, the more reducing gas is produced by coal gasification, and the higher the denitrification efficiency is. However, in order to avoid the temperature being too high, which may burn the refractory material and the furnace body, part of the raw material is input into the reduction part 2 for cooling. Therefore, the raw material input by the temperature regulating material pipe 53 is mainly used to adjust the temperature inside the reduction part 2.
[0036] The bottom end of the main furnace part 1 is welded to the reduction part 2 through a truncated cone sleeve, and the bottom end of the reduction part 2 is conical.
[0037] The air supply pipe 3 includes a main air duct 31, a ring air duct 32 which is arranged at the other end of the main air duct 31 through a tee pipe and is environmentally friendly to the outer periphery of the main furnace part 1, and a plurality of branch air ducts 33 which are evenly arranged on the inner side of the ring air duct 32 and inserted into the main furnace part 1. The branch air duct 33 is inclined upward from the outside to the inside, and one end of the branch air duct 33 away from the ring air duct 32 is flush with the inner wall of the main furnace part 1.
[0038] The air delivery pipe 3 is designed to be annular, and the hot air is input into the main furnace part 1 from different directions through multiple branch air pipes 33, which effectively ensures the uniformity of the hot air and can better mix the coal powder output from the upper ring powder pipe 43 with the hot air, so that the coal powder can be fully burned.
[0039] See also Figure 4 The main powder pipe 41 is connected to the powder distribution pipe 42 through a tee pipe, and a distribution plate is arranged in the tee pipe. The distribution plate controls the proportion of pulverized coal entering the main furnace part 1 and the reduction part 2, so that the generated CO can meet the demand of destocking as much as possible.
[0040] In this embodiment, the upper ring powder pipe 43 is located above the ring air pipe 32, the powder conveying pipe 45 inside the upper ring powder pipe 43 is in a horizontal state and is located above the diversion air pipe 33, and the powder conveying pipe 45 inside the lower ring powder pipe 44 is inclined upward from outside to inside.
[0041] The powder conveying pipe 45 inside the upper ring powder pipe 43 is located above the split air pipe 33, so as to effectively mix the pulverized coal input into the main furnace part 1 with the hot air below.
[0042] The raw material pipe 5 is connected to the furnace body in a downwardly inclined state from outside to inside, the end of the decomposition material pipe 52 away from the feed pipe 51 is located above the upper ring powder pipe 43, and the end of the temperature control material pipe 53 away from the feed pipe 51 is located above the lower ring powder pipe 44.
[0043] By adopting the above technical solution, the raw meal output from the decomposition pipe 52 falls naturally under the action of gravity, while the hot air and coal powder below fly upward under the action of air. After the two meet, they can be fully mixed together, so that the decomposition rate of carbonate can reach an ideal state as much as possible. Example
[0044] See also Figure 5-6 A low-nitrogen decomposition furnace, in the actual production process, the main powder pipe 41 and the powder distribution pipe 42 are connected by a tee pipe, and at the same time, an adjustable distributor 6 extending to the inside of the tee pipe is provided outside the tee pipe. The adjustable distributor 6 can be used to more accurately control the proportion of coal powder entering the main furnace part 1 and the reduction part 2.
[0045] In this embodiment, the adjustable distributor 6 includes an electric push rod 61 with one end rotatably mounted on the side wall of the main powder pipe 41, an adjusting rod 62 hinged at the movable end of the electric push rod 61, and a movable distributor plate 63 rotatably mounted inside the three-way pipe and with the axial rod extending outside the three-way pipe. The movable distributor plate 63 is located on the axial rod outside the three-way pipe and is fixedly connected to the other end of the adjusting rod 62.
[0046] When the angle of the movable material distribution plate 63 needs to be adjusted, the electric push rod 61 is extended and retracted to drive the adjusting rod 62 to rotate with the axis of the movable material distribution plate 63 as the center, thereby rotating the movable material distribution plate 63, so that the coal powder in the main powder pipe 41 passes through the three-way pipe, and the ratio of the two coal powders can be adjusted.
[0047] Working principle: The furnace body is divided into the main furnace part 1 and the reduction part 2. The pulverized coal is input through the main powder pipe 41, and then after passing through the three-way pipe, it is divided into two streams of pulverized coal by the powder distribution pipe 42. One stream of pulverized coal enters the main furnace part 1 through the upper ring powder pipe 43, and the other stream of pulverized coal enters the reduction part 2 through the lower ring powder pipe 44. At the same time, the annular air duct 32 inputs hot air from all directions to the main furnace part 1 through the diversion air duct 33. The raw material enters the main furnace part 1 and the reduction part 2 respectively through the decomposition material pipe 52 and the temperature adjustment material pipe 53. In the reduction part 2, the pulverized coal will be decomposed into H2, CH4, CO and other reducing gases in a high temperature and low oxygen environment. According to the principle of the body, NOx generated in the kiln is reduced into N2, so as to reduce the concentration of NOx and reduce the N2 generated by the combustion of coal powder in the decomposition furnace. At the same time, since the lower ring powder pipe 44 in the reduction part 2 is arranged at the lowest part of the cone of the reduction part 2, the reduction zone in the reduction part 2 is ensured to be as large as possible, which can prevent the tail coal from falling into the smoke chamber and forming a high temperature or crust in the smoke chamber. The raw material output from the decomposition material pipe 52 falls naturally under the action of gravity, while the hot air and coal powder below fly upward under the action of air. After the two meet, they can be fully mixed together, so that the decomposition rate of carbonate can reach an ideal state as much as possible.
[0048] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A low nitrogen decomposition furnace, characterized in that: The invention comprises a furnace body, wherein the furnace body comprises a main furnace part (1) and a reduction part (2) welded to the bottom of the main furnace part (1), an air delivery pipe (3) is provided on the outer surface of one end of the main furnace part (1) close to the reduction part (2), and a pulverized coal pipe (4) is provided on the outer side of the main furnace part (1). The pulverized coal pipe (4) comprises a main powder pipe (41), a powder distribution pipe (42) vertically arranged at one end of the main powder pipe (41), an upper powder ring pipe (43) arranged at one end of the powder distribution pipe (42) and surrounding the periphery of the main furnace part (1), and a lower powder ring pipe (44) arranged at the other end of the powder distribution pipe (42) and surrounding the periphery of the bottom end of the reduction part (2), and the inner sides of the upper powder ring pipe (43) and the lower powder ring pipe (44) are both provided with a powder conveying pipe (45) inserted into the furnace body; Raw material pipes (5) are provided on both sides of the furnace body, the raw material pipes (5) comprising a feed pipe (51), a decomposition pipe (52) arranged at one end of the feed pipe (51) via a three-way joint, and a temperature regulating pipe (53), the other end of the decomposition pipe (52) being inserted into the main furnace part (1), and the other end of the temperature regulating pipe (53) being inserted into the reduction part (2).
2. A low nitrogen decomposition furnace according to claim 1, characterized in that: The bottom end of the main furnace part (1) is welded to the reduction part (2) via a truncated cone sleeve, and the bottom end of the reduction part (2) is conical.
3. A low nitrogen decomposition furnace according to claim 1, characterized in that: The air delivery pipe (3) comprises a main air pipe (31), a ring air pipe (32) arranged at the other end of the main air pipe (31) through a tee pipe and environmentally friendly to the periphery of the main furnace part (1), and a plurality of branch air pipes (33) evenly arranged on the inner side of the ring air pipe (32) and inserted into the interior of the main furnace part (1), wherein the branch air pipe (33) is inclined upward from the outside to the inside, and one end of the branch air pipe (33) away from the ring air pipe (32) is flush with the inner wall of the main furnace part (1).
4. A low nitrogen decomposition furnace according to claim 1, characterized in that: The main powder pipe (41) and the powder distribution pipe (42) are connected via a tee pipe, and a material distribution plate is provided inside the tee pipe.
5. A low nitrogen decomposition furnace according to claim 1, characterized in that: The main powder pipe (41) and the powder distribution pipe (42) are connected via a tee pipe, and an adjustable distributor (6) extending into the interior of the tee pipe is provided outside the tee pipe, and the adjustable distributor (6) comprises an electric push rod (61) rotatably mounted at one end on the side wall of the main powder pipe (41), an adjusting rod (62) hinged at the movable end of the electric push rod (61), and a movable distributor plate (63) rotatably mounted inside the tee pipe and with an axial rod extending out of the tee pipe, wherein the movable distributor plate (63) is located on an axial rod outside the tee pipe and is fixedly connected to the other end of the adjusting rod (62).
6. A low nitrogen decomposition furnace according to claim 3, characterized in that: The upper ring powder pipe (43) is located above the ring air pipe (32); the powder conveying pipe (45) inside the upper ring powder pipe (43) is in a horizontal state and is located above the split air pipe (33); and the powder conveying pipe (45) inside the lower ring powder pipe (44) is in an upwardly inclined state from outside to inside.
7. A low nitrogen decomposition furnace according to claim 1, characterized in that: The raw material pipe (5) is connected to the furnace body in a downwardly inclined state from the outside to the inside; one end of the decomposition material pipe (52) away from the feed pipe (51) is located above the upper ring powder pipe (43); and one end of the temperature control material pipe (53) away from the feed pipe (51) is located above the lower ring powder pipe (44).