Waste gas treatment system for reducing nitrogen oxide in sleeve kiln

Abstract

The utility model relates to a waste gas treatment system for reducing nitrogen oxide in a sleeve kiln and belongs to the field of calcium carbide production. Comprising a sleeve kiln, a waste gas dedusting and cooling mechanism, a waste gas branch pipe heat exchanger, a driving fan and a cooling fan, the waste gas dedusting and cooling mechanism comprises a gravity deduster, a waste gas fan and a cooler; a waste gas outlet at the top end of the sleeve kiln is connected with the gravity dust collector through a pipeline, the gravity dust collector is connected with the waste gas fan through a pipeline, the waste gas fan is connected with the cooler through a pipeline, and the cooler is connected with the lime cooling pipe through a pipeline. According to the utility model, the waste gas which is directly exhausted in the prior art is re-injected into the sleeve kiln to participate in secondary combustion after being dedusted and cooled, so that the original natural air which is used for sucking and cooling lime through a waste gas fan is replaced as combustion-supporting air, and the content of oxygen in the combustion-supporting air is further reduced; and finally, the purposes of reducing the generation of thermal nitrogen oxides and reducing the emission of nitrogen oxides are achieved.

Description

Technical Field

[0001] This utility model relates to the field of calcium carbide production, and in particular to a waste gas treatment system for reducing nitrogen oxides in a sleeve kiln. Background Technology

[0002] The main raw materials for calcium carbide production are lime and carbon. The sleeve kiln mainly provides lime for calcium carbide furnace production. Limestone is transported to the limestone silo in front of the kiln by a belt conveyor. According to the weight set by the weighing hopper, the limestone is unloaded by an electric vibrating feeder. The limestone is added to the weighing hopper through a chute. The hydraulic door of the weighing hopper is opened to unload the limestone into the hopper. The door of the intermediate silo at the top of the kiln is opened, and the winch lifts the hopper to the top of the kiln, unloading the limestone into the rotary distributor. With the hopper closed, the rotary distributor rotates to a specific position, and with the intermediate silo door closed, the hopper is opened to unload the material into the kiln. The limestone is burned into finished active lime through the preheating, calcination, and cooling process in the kiln. At this time, the finished lime is located above the ash discharge drawer. The lime is unloaded into the lime silo below the kiln through the ash discharge drawer. Then, the vibrating feeder unloads the lime from the lime silo onto the ash discharge belt, and then the ash discharge belt transports the finished lime to the batching station.

[0003] The problems in the above production process are as follows: the production of the sleeve kiln mainly uses the purified exhaust gas from the calcium carbide furnace mixed with air in a certain proportion to calcine limestone. The combustion air participating in the combustion in the sleeve kiln consists of three parts:

[0004] (1) Cooling air cools the secondary combustion air after the inner sleeve is cooled;

[0005] (2) Drive air passes through the heat exchanger;

[0006] (3) The exhaust fan draws in the natural air used to cool the lime.

[0007] Because the original design of the sleeve kiln was for oxygen-fueled combustion, the oxygen in the combustion air could not fully participate in the combustion during the calcination of lime, resulting in excessive nitrogen oxide content and thus failing to meet emission standards. Utility Model Content

[0008] The technical problem to be solved by this utility model is to provide a waste gas treatment system for reducing nitrogen oxides in a sleeve kiln, so as to solve the above-mentioned problem.

[0009] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: A waste gas treatment system for reducing nitrogen oxides in a sleeve kiln includes: a sleeve kiln, a waste gas dust removal and cooling mechanism, a waste gas branch pipe heat exchanger, a drive fan, and a cooling fan; both ends of the waste gas dust removal and cooling mechanism are connected one-to-one to the waste gas outlet at the top of the sleeve kiln and the lime cooling pipe at the bottom of the sleeve kiln, and the lime cooling pipe is equipped with a lime cooling air regulating valve; both ends of the waste gas branch pipe heat exchanger are connected one-to-one to the waste gas outlet at the top of the sleeve kiln and the lime silo at the bottom of the sleeve kiln. The drive fan is connected to the exhaust gas branch pipe heat exchanger, the exhaust gas branch pipe heat exchanger is connected to the multi-layer ring pipe on the sleeve kiln, and the cooling fan is connected to the cooling air inlets of the lower inner sleeve and upper inner sleeve in the sleeve kiln; the exhaust gas dust removal and cooling mechanism includes: a gravity dust collector, an exhaust gas fan, and a cooler; the exhaust gas outlet at the top of the sleeve kiln is connected to the gravity dust collector through a pipe, the gravity dust collector is connected to the exhaust gas fan through a pipe, the exhaust gas fan is connected to the cooler through a pipe, and the cooler is connected to the lime cooling pipe through a pipe.

[0010] The beneficial effects of this utility model are: the exhaust gas dust removal and cooling mechanism facilitates the reinjection of directly discharged exhaust gas from the prior art into the sleeve kiln for secondary combustion after dust removal and cooling through gravity dust collectors and coolers, thereby replacing the natural air originally drawn by the exhaust gas fan to cool the lime as combustion air, thus reducing the oxygen content in the combustion air; at the same time, in conjunction with the drive fan and cooling fan, the oxygen content participating in secondary combustion is reduced by reducing the flow rate of the combustion air, ultimately achieving the purpose of reducing the generation of thermal nitrogen oxides and reducing nitrogen oxide emissions.

[0011] Based on the above technical solution, the present invention can be further improved as follows.

[0012] Furthermore, an exhaust gas regulating valve is installed on the pipe connecting the exhaust gas fan and the cooler to regulate the flow rate of gas entering the cooler.

[0013] The beneficial effects of adopting the above-mentioned further scheme are: the exhaust gas regulating valve combined with the lime cooling air regulating valve is conducive to regulating the content of exhaust gas entering the sleeve kiln and after dust removal and cooling treatment, thereby avoiding the natural air for cooling lime being drawn in by the exhaust gas fan as combustion air, and thus reducing the oxygen content in the combustion air.

[0014] Furthermore, the exhaust gas dust removal and cooling mechanism also includes: a bag filter, a dust removal fan, and a direct exhaust chimney; the air inlet and outlet of the bag filter are connected to the exhaust gas fan and the dust removal fan respectively through pipes, and the dust removal fan is connected to the direct exhaust chimney through pipes.

[0015] The beneficial effects of adopting the above-mentioned further scheme are: the bag filter helps to treat a portion of the exhaust gas discharged from the top of the kiln and then discharge it into the atmosphere through a direct chimney, thus avoiding the pollution caused by direct discharge of exhaust gas; and the dust removal fan helps to provide power for the discharge of exhaust gas.

[0016] Furthermore, the multi-layer ring pipe is a four-layer annular tubular structure sleeved on the outer wall of the sleeve kiln. The multi-layer ring pipe consists of a first ring pipe, a second ring pipe, a third ring pipe, and a fourth ring pipe from bottom to top. The first ring pipe is connected to the second ring pipe and the third ring pipe through a pipe, and the fourth ring pipe is connected to the inlet of the lower combustion chamber in the sleeve kiln.

[0017] The beneficial effects of adopting the above-mentioned further scheme are: the multi-layer ring pipe is conducive to inputting the driving air after the driving fan has been heated by the heat exchanger into the lower combustion chamber in the sleeve kiln, and at the same time, it is conducive to adjusting the flow rate of the secondary combustion air after the cooling fan cools the lower inner sleeve and then inputs it into the upper and lower combustion chambers.

[0018] Furthermore, the exhaust gas branch heat exchanger is connected to the fourth ring pipe through a pipeline, and the driving air driven by the drive fan after heat exchange in the exhaust gas branch heat exchanger is injected into the lower combustion chamber inlet.

[0019] The beneficial effect of adopting the above-mentioned further scheme is that it is advantageous to input the driving air after heat exchange by the drive fan into the lower combustion chamber of the sleeve kiln as a secondary combustion-supporting gas.

[0020] Furthermore, a lower combustion chamber flow regulating valve and an upper combustion chamber flow regulating valve are respectively installed on the pipes that connect the first ring pipe to the second ring pipe and the third ring pipe.

[0021] The beneficial effects of adopting the above-mentioned further scheme are that the upper combustion chamber flow regulating valve and the lower combustion chamber flow regulating valve are conducive to regulating the flow rate of secondary combustion air entering the upper combustion chamber and the lower combustion chamber.

[0022] Furthermore, the lower inner sleeve is connected to the first layer of ring pipe via a pipe.

[0023] The beneficial effect of adopting the above-mentioned further scheme is that it facilitates the distribution of the gas after cooling the lower inner sleeve to the upper and lower combustion chambers through the first layer of ring pipe as secondary combustion air.

[0024] Furthermore, the second-layer annular pipe is connected to the lower combustion chamber inlet via a pipe.

[0025] The beneficial effect of adopting the above-mentioned further scheme is that it facilitates the input of secondary combustion air, after the flow rate has been regulated by the lower combustion chamber flow regulating valve, into the lower combustion chamber.

[0026] Furthermore, the third ring pipe is connected to the inlet of the upper combustion chamber in the sleeve kiln via a pipeline.

[0027] The beneficial effect of adopting the above-mentioned further scheme is that it facilitates the input of secondary combustion air, after the flow rate has been regulated by the upper combustion chamber flow regulating valve, into the upper combustion chamber.

[0028] Furthermore, the cooling air inlet of the upper inner sleeve is connected to the upper inner sleeve in the sleeve kiln, and the upper inner sleeve is connected to the external atmosphere through a pipe.

[0029] The beneficial effect of adopting the above-mentioned further solution is that it facilitates the discharge of some of the cooling air driven by the cooling fan into the atmosphere after passing through the upper inner sleeve. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure provided for an embodiment of the present utility model.

[0031] in, Figure 1 The arrows in the diagram indicate the direction of gas flow.

[0032] The attached diagram lists the components represented by each number as follows:

[0033] 1. Sleeve kiln; 2. Exhaust gas dust removal and cooling mechanism; 3. Exhaust gas branch pipe heat exchanger; 4. Drive fan; 5. Cooling fan; 11. Lime cooling pipe; 12. Lime cooling air regulating valve; 13. Lower inner sleeve; 14. Multi-layer ring pipe; 15. Upper combustion chamber inlet; 16. Lower combustion chamber inlet; 17. Upper inner sleeve; 18. Upper inner sleeve cooling air inlet; 21. Gravity dust collector; 22. Exhaust gas fan; 23. Bag filter; 24. Dust removal fan; 25. Direct exhaust chimney; 26. Exhaust gas regulating valve; 27. Cooler; 141. Lower combustion chamber flow regulating valve; 142. Upper combustion chamber flow regulating valve. Detailed Implementation

[0034] The principles and features of this utility model are described below. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0035] like Figure 1As shown, a waste gas treatment system for reducing nitrogen oxides in a sleeve kiln includes: a sleeve kiln 1, a waste gas dust removal and cooling mechanism 2, a waste gas branch pipe heat exchanger 3, a drive fan 4, and a cooling fan 5. The two ends of the waste gas dust removal and cooling mechanism 2 are connected one-to-one to the waste gas outlet at the top of the sleeve kiln 1 and the lime cooling pipe 11 at the bottom of the sleeve kiln 1. A lime cooling air regulating valve 12 is installed on the lime cooling pipe 11. The two ends of the waste gas branch pipe heat exchanger 3 are connected one-to-one to the waste gas outlet at the top of the sleeve kiln 1 and the lime silo at the bottom of the sleeve kiln 1. The drive fan 4 is connected to the waste gas branch pipe heat exchanger 3. The exhaust gas branch heat exchanger 3 is connected to the multi-layer ring pipe 14 on the sleeve kiln 1, and the cooling fan 5 is connected to the lower inner sleeve 13 and the upper inner sleeve cooling air inlet 18 in the sleeve kiln 1. The exhaust gas dust removal and cooling mechanism 2 includes: a gravity dust collector 21, an exhaust gas fan 22, and a cooler 27. The exhaust gas outlet at the top of the sleeve kiln 1 is connected to the gravity dust collector 21 through a pipe, the gravity dust collector 21 is connected to the exhaust gas fan 22 through a pipe, the exhaust gas fan 22 is connected to the cooler 27 through a pipe, and the cooler 27 is connected to the lime cooling pipe 11 through a pipe.

[0036] It should be noted that the oxygen content in the exhaust gas discharged from the top of the sleeve kiln 1 is low. Compared with the natural air used to cool lime by the exhaust gas fan in the prior art, the oxygen content of the exhaust gas after dust removal and cooling treatment is greatly reduced.

[0037] The beneficial effects of this utility model are: the exhaust gas dust removal and cooling mechanism facilitates the reinjection of exhaust gas that should have been directly discharged into the kiln for secondary combustion after dust removal and cooling through the gravity dust collector and cooler, thereby replacing the natural air that was originally drawn by the exhaust gas fan to cool the lime as combustion air, thus reducing the oxygen content in the combustion air; at the same time, in conjunction with the drive fan and cooling fan, the oxygen content participating in secondary combustion is reduced by reducing the flow rate of the combustion air, ultimately achieving the purpose of reducing the generation of thermal nitrogen oxides and reducing nitrogen oxide emissions.

[0038] Preferred, such as Figure 1 As shown, the exhaust gas fan 22 and the cooler 27 are connected by an exhaust gas regulating valve 26, which regulates the flow rate of gas entering the cooler 27.

[0039] The beneficial effects of adopting the above-mentioned preferred scheme are: the exhaust gas regulating valve combined with the lime cooling air regulating valve is conducive to regulating the content of exhaust gas entering the sleeve kiln and after dust removal and cooling treatment, thereby avoiding the natural air for cooling lime being drawn in by the exhaust gas fan as combustion air, and thus reducing the oxygen content in the combustion air.

[0040] Preferred, such as Figure 1As shown, the exhaust gas dust removal and cooling mechanism 2 further includes: a bag filter 23, a dust removal fan 24, and a direct exhaust chimney 25; the air inlet and outlet of the bag filter 23 are connected to the exhaust gas fan 22 and the dust removal fan 24 through pipes, and the dust removal fan 24 is connected to the direct exhaust chimney 25 through pipes.

[0041] The advantages of adopting the above-mentioned preferred scheme are: the bag filter helps to treat a portion of the exhaust gas discharged from the top of the kiln and then discharge it into the atmosphere through a direct chimney, thus avoiding the pollution caused by direct discharge of exhaust gas; and the dust removal fan helps to provide power for the discharge of exhaust gas.

[0042] Preferred, such as Figure 1 As shown, the multi-layer ring pipe 14 is a four-layer annular tubular structure sleeved on the outer wall of the sleeve kiln 1. The multi-layer ring pipe 14 consists of a first layer ring pipe, a second layer ring pipe, a third layer ring pipe, and a fourth layer ring pipe from bottom to top. The first layer ring pipe is connected to the second layer ring pipe and the third layer ring pipe through a pipe. The fourth layer ring pipe is connected to the lower combustion chamber inlet 16 in the sleeve kiln 1.

[0043] The advantages of adopting the above-mentioned preferred scheme are: the multi-layer ring pipe is conducive to inputting the driving air after heat exchange by the drive fan into the lower combustion chamber of the sleeve kiln, and at the same time, it is conducive to adjusting the flow rate of the secondary combustion air input into the upper and lower combustion chambers after the cooling fan cools the lower inner sleeve.

[0044] Preferred, such as Figure 1 As shown, the exhaust gas branch heat exchanger 3 is connected to the fourth ring pipe through a pipe, and the driving air driven by the drive fan 4 after heat exchange in the exhaust gas branch heat exchanger 3 is injected into the lower combustion chamber inlet 16.

[0045] The advantages of adopting the above preferred scheme are: it is beneficial to input the driving air after heat exchange by the drive fan through the heat exchanger into the lower combustion chamber of the sleeve kiln as a secondary combustion-supporting gas.

[0046] Preferred, such as Figure 1 As shown, the pipes connecting the first ring pipe, the second ring pipe, and the third ring pipe are equipped with corresponding lower combustion chamber flow regulating valves 141 and upper combustion chamber flow regulating valves 142.

[0047] It should be noted that in the technical solution of this utility model, the connecting pipes of the first layer ring pipe to the lower combustion chamber flow regulating valve 141 and the upper combustion chamber flow regulating valve 142 are also connected to the external atmosphere through another pipe, that is, part of the cooling air output from the first layer ring pipe is discharged to the atmosphere.

[0048] The advantages of adopting the above preferred scheme are that the upper combustion chamber flow regulating valve and the lower combustion chamber flow regulating valve are conducive to regulating the flow rate of secondary combustion air entering the upper combustion chamber and the lower combustion chamber.

[0049] Preferred, such as Figure 1 As shown, the lower inner sleeve 13 is connected to the first layer of ring pipe through a pipe.

[0050] The advantages of adopting the above-mentioned preferred scheme are: it facilitates the distribution of the gas after cooling the lower inner sleeve to the upper and lower combustion chambers through the first layer of ring pipe as secondary combustion air.

[0051] Preferred, such as Figure 1 As shown, the second ring pipe is connected to the lower combustion chamber inlet 16 via a pipe.

[0052] The advantages of adopting the above-mentioned preferred scheme are: it facilitates the input of secondary combustion air, after the flow rate has been regulated by the lower combustion chamber flow regulating valve, into the lower combustion chamber.

[0053] Preferred, such as Figure 1 As shown, the third ring pipe is connected to the upper combustion chamber inlet 15 in the sleeve kiln 1 via a pipe.

[0054] The beneficial effect of adopting the above preferred scheme is that it facilitates the input of secondary combustion air, after the flow rate is regulated by the upper combustion chamber flow regulating valve, into the upper combustion chamber.

[0055] Preferred, such as Figure 1 As shown, the cooling air inlet 18 of the upper inner sleeve is connected to the upper inner sleeve 17 in the sleeve kiln 1, and the upper inner sleeve 17 is connected to the external atmosphere through a pipe.

[0056] The beneficial effect of adopting the above preferred solution is that it facilitates the discharge of some of the cooling air driven by the cooling fan into the atmosphere after passing through the upper inner sleeve.

[0057] The working process of this utility model will be described below through an embodiment:

[0058] like Figure 1 As shown, firstly, the exhaust gas discharged from the top of the sleeve kiln 1, after being dusted by the gravity dust collector 21 and cooled by the cooler 27, is reintroduced into the sleeve kiln 1 through the lime cooling pipe 11 as a secondary combustion gas. At this time, the oxygen content of the exhaust gas entering the sleeve kiln 1 is low. Therefore, the amount of natural air entering the lime cooling system is controlled by adjusting the lime cooling air regulating valve 12, from 11000 Nm³. 3 / h adjusted to 7500Nm 3 / h;

[0059] Secondly, the driving air volume generated by the driving fan 4 is 15000 Nm.3 / h adjusted to 13000Nm 3 / h;

[0060] Third, reduce the combustion air volume in the upper and lower combustion chambers. This is achieved by adjusting the combustion air volume in the upper combustion chamber using the upper combustion chamber flow regulating valve 142, reducing it from 1400 Nm³. 3 / h adjusted to 900 Nm 3 / h, the combustion air volume in the lower combustion chamber is adjusted from 2000Nm³ / h via the lower combustion chamber flow regulating valve 141. 3 / h adjusted to 1500Nm 3 / h, while reducing the coefficient of secondary combustion air, the coefficient of the lower combustion chamber is adjusted from 0.38 to 0.32, and the coefficient of the upper combustion chamber is adjusted from 0.3 to 0.2.

[0061] After adjustment, the oxygen content participating in secondary combustion in the sleeve kiln 1 is reduced, and both the upper and lower combustion chambers become oxygen-deficient combustion. The calcination temperature of the upper combustion chamber is reduced from the original 1220℃ to 1130℃, and the calcination temperature of the lower combustion chamber is reduced from the original 1150℃ to 1050℃. By reducing the calcination temperature of the combustion chamber, the generation of thermal nitrogen is suppressed, thereby reducing the generation of nitrogen oxides in the kiln.

[0062] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0065] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0066] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0067] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A waste gas treatment system for reducing nitrogen oxides in a sleeve kiln, characterized in that, include: The sleeve kiln (1), the exhaust gas dust removal and cooling mechanism (2), the exhaust gas branch heat exchanger (3), the drive fan (4) and the cooling fan (5); The two ends of the exhaust gas dust removal and cooling mechanism (2) are connected one-to-one with the exhaust gas outlet at the top of the sleeve kiln (1) and the lime cooling pipe (11) at the bottom of the sleeve kiln (1). The lime cooling pipe (11) is equipped with a lime cooling air regulating valve (12). The two ends of the exhaust gas branch heat exchanger (3) are connected one-to-one with the exhaust gas outlet at the top of the sleeve kiln (1) and the lime silo at the bottom of the sleeve kiln (1). The drive fan (4) is connected to the exhaust gas branch heat exchanger (3). The exhaust gas branch heat exchanger (3) is connected to the multi-layer ring pipe (14) on the sleeve kiln (1). The cooling fan (5) is connected to the lower inner sleeve (13) and the upper inner sleeve cooling air inlet (18) in the sleeve kiln (1). The exhaust gas dust removal and cooling mechanism (2) includes: a gravity dust collector (21), an exhaust gas fan (22), and a cooler (27); the exhaust gas outlet at the top of the sleeve kiln (1) is connected to the gravity dust collector (21) through a pipe, the gravity dust collector (21) is connected to the exhaust gas fan (22) through a pipe, the exhaust gas fan (22) is connected to the cooler (27) through a pipe, and the cooler (27) is connected to the lime cooling pipe (11) through a pipe.

2. The waste gas treatment system for reducing nitrogen oxides in a sleeve kiln according to claim 1, characterized in that, The exhaust gas fan (22) and the cooler (27) are connected by an exhaust gas regulating valve (26) that regulates the flow rate of gas entering the cooler (27).

3. The waste gas treatment system for reducing nitrogen oxides in a sleeve kiln according to claim 1, characterized in that, The exhaust gas dust removal and cooling mechanism (2) further includes: a bag filter (23), a dust removal fan (24), and a direct exhaust chimney (25); the air inlet and outlet of the bag filter (23) are connected to the exhaust gas fan (22) and the dust removal fan (24) through pipes, and the dust removal fan (24) is connected to the direct exhaust chimney (25) through pipes.

4. The waste gas treatment system for reducing nitrogen oxides in a sleeve kiln according to claim 1, characterized in that, The multi-layer ring pipe (14) is a four-layer annular tubular structure sleeved on the outer wall of the sleeve kiln (1). The multi-layer ring pipe (14) consists of a first ring pipe, a second ring pipe, a third ring pipe and a fourth ring pipe from bottom to top. The first ring pipe is connected to the second ring pipe and the third ring pipe through a pipe. The fourth ring pipe is connected to the lower combustion chamber inlet (16) in the sleeve kiln (1).

5. The waste gas treatment system for reducing nitrogen oxides in a sleeve kiln according to claim 4, characterized in that, The exhaust gas branch heat exchanger (3) is connected to the fourth ring pipe through a pipe, and the driving air driven by the driving fan (4) after heat exchange in the exhaust gas branch heat exchanger (3) is injected into the lower combustion chamber inlet (16).

6. The waste gas treatment system for reducing nitrogen oxides in a sleeve kiln according to claim 4, characterized in that, The first ring pipe is connected to the second ring pipe and the third ring pipe, and the pipe is equipped with a lower combustion chamber flow regulating valve (141) and an upper combustion chamber flow regulating valve (142) respectively.

7. The waste gas treatment system for reducing nitrogen oxides in a sleeve kiln according to claim 4, characterized in that, The lower inner sleeve (13) is connected to the first layer of ring pipe through a pipe.

8. The waste gas treatment system for reducing nitrogen oxides in a sleeve kiln according to claim 4, characterized in that, The second ring pipe is connected to the lower combustion chamber inlet (16) via a pipe.

9. The waste gas treatment system for reducing nitrogen oxides in a sleeve kiln according to claim 4, characterized in that, The third ring pipe is connected to the upper combustion chamber inlet (15) of the sleeve kiln (1) via a pipeline.

10. The waste gas treatment system for reducing nitrogen oxides in a sleeve kiln according to claim 1, characterized in that, The cooling air inlet (18) of the upper inner sleeve is connected to the upper inner sleeve (17) in the sleeve kiln (1), and the upper inner sleeve (17) is connected to the external atmosphere through a pipe.

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