CN211575912U - Equipment for reducing emission of nitrogen oxides in rotary kiln - Google Patents
Equipment for reducing emission of nitrogen oxides in rotary kiln Download PDFInfo
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- CN211575912U CN211575912U CN202020213092.2U CN202020213092U CN211575912U CN 211575912 U CN211575912 U CN 211575912U CN 202020213092 U CN202020213092 U CN 202020213092U CN 211575912 U CN211575912 U CN 211575912U
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Abstract
The utility model relates to a device for reducing the emission of nitrogen oxides in a rotary kiln, which comprises a decomposing furnace, wherein the decomposing furnace is sequentially divided into a spraying area, a main combustion area and a reduction area from top to bottom, and the reduction area is communicated with a smoke chamber of the rotary kiln; the spray zone is communicated with a spray gun, the upper part of the reduction zone is in a conical shape with a narrow top and a wide bottom, the lower part of the reduction zone is in an inverted cone shape with a wide top and a narrow bottom, the upper part of the reduction zone is communicated with an air inlet pipe, the lower part of the reduction zone is provided with an atomizing mechanism and a plurality of first coal injection pipes, and the atomizing mechanism comprises an atomizer, an air distribution ring and a spray head which are mutually connected and matched; the flue is provided with a second coal injection pipe which is communicated with the first coal injection pipe to form the same coal feeding mechanism. The utility model has simple and reasonable structure, carries out a plurality of reduction reactions in the decomposing furnace, effectively reduces the content of nitrogen oxide in the flue gas, reaches the national emission standard, saves energy and protects environment; the dosage of ammonia water and the escape of ammonia gas are reduced, and the device is efficient and energy-saving.
Description
Technical Field
The utility model relates to a cement manufacture equipment technical field specifically, relates to an equipment that reduces rotary kiln nitrogen oxide and discharges.
Background
China has cement output which is continuously positioned at the top of the world for many years. The nitrogen oxides account for an important proportion in the tail gas pollution of the cement kiln. The emission reduction problem of nitrogen oxides becomes a significant problem restricting the environmental and economic development of China. At present, a decomposing furnace is used as important pretreatment equipment in the cement production process of a cement plant and is mainly used for decomposing carbonate into calcium oxide and carbon dioxide, one end of the decomposing furnace is connected with the kiln tail of a rotary kiln, smoke can be discharged from the kiln tail, and a large amount of nitrogen oxides exist in the smoke. In addition, the pulverized coal injected into the decomposing furnace can generate reducing gas after insufficient combustion, and the reducing gas reacts with the nitrogen oxide, so that the emission of the nitrogen oxide in the flue gas is reduced.
SUMMERY OF THE UTILITY MODEL
Aiming at the defects in the prior art, the utility model provides a device for reducing the emission of nitrogen oxides in a rotary kiln, which comprises a decomposing furnace, wherein the decomposing furnace is sequentially divided into a spraying area, a main combustion area and a reduction area from top to bottom, and the bottom of the reduction area is communicated with a smoke chamber of the rotary kiln through a flue;
the diameter of the spraying area is smaller than that of the main combustion area, so that gas is more concentrated in the spraying area, the spraying range is reduced, the spraying effect is facilitated, the spraying area is communicated with a spray gun, ammonia water spraying operation is carried out on the gas in the spraying area, the ammonia water is contacted with tail gas, the reduction reaction of the last step is carried out, and the nitrogen oxides in the tail gas are ensured to be fully reacted into pollution-free gas;
the upper part of the reduction zone is in a conical shape with a narrow top and a wide bottom, so that the speed of the gas in the reduction zone entering the main combustion zone is favorably slowed down, the reduction reaction time of the reduction zone is prolonged, the lower part of the reduction zone is in an inverted cone shape with a wide top and a narrow bottom, the upper part of the reduction zone is communicated with an air inlet pipe, oxygen contained in air introduced into the air inlet pipe and the gas in the reduction zone enter the main combustion zone together, the complete combustion of all the gases in the main combustion zone is promoted, and the discharge of various harmful gases is avoided; the lower part of the reduction zone is provided with an atomizing mechanism and a plurality of first coal injection pipes, the atomizing mechanism comprises an atomizer, an air distribution ring and spray heads, a mist outlet of the atomizer is connected with a pipeline, the pipeline is communicated with the air distribution ring, the air distribution ring is fixed on the outer wall of the lower part of the reduction zone through a fixing part, the spray heads are fixed on the inner wall of the lower part of the reduction zone and are uniformly distributed along the circumferential direction of the inner wall, an air inlet end of the spray heads is communicated with the air distribution ring, and the first coal injection pipes are distributed below the atomizing mechanism and are uniformly distributed along the circumferential direction of the lower part of the reduction zone; the atomizer atomizes water entering the atomizer, the atomized water enters the gas distribution ring through a pipeline, and is uniformly sprayed and swept to the lower part of a reduction zone through a spray head, the atomized water is evaporated and gasified in high-temperature flue gas, and a carbon monoxide and hydrogen distribution area with certain concentration is formed by matching with pulverized coal sprayed by a first coal spraying pipe, and the nitrogen oxides in tail gas of a rotary kiln in the decomposing furnace are converted into pollution-free nitrogen through the reduction gas;
the flue is a smooth arc-shaped pipe, a second coal injection pipe is arranged in the middle of the flue, and the second coal injection pipe and the first coal injection pipe are communicated with the same coal feeding mechanism. The incomplete combustion of the pulverized coal sprayed by the second coal injection pipe and the nitrogen oxide in the tail gas of the rotary kiln carry out the first reduction reaction, the arc-shaped pipe structure of the flue improves the smoothness of the tail gas entering the decomposing furnace, increases the time and the distance of the first reduction reaction, and promotes the reduction effect of the first oxidation reduction.
Preferably, the coal injection direction of the first coal injection pipe is not intersected with the central axis of the reduction zone, and the coal powder injected into the bottom of the reduction zone is insufficiently combusted at the position to generate more reducing gas, so that the entering tail gas of the rotary kiln is favorable for carrying out secondary reduction reaction with the reducing gas again to sufficiently reduce nitrogen oxides of the tail gas.
Preferably, the coal injection direction of the second coal injection pipe on the flue is parallel to the central axis of the rotary kiln. The rotary kiln tail gas in second coal injection pipe and the flue is more abundant due to the arrangement of the rotary kiln tail gas, the coal powder sprayed by the second coal injection pipe is not sufficiently combusted due to long-time contact, and the generated reductive gas enters the decomposing furnace after the reductive gas is firstly subjected to contact reaction with the rotary kiln tail gas in the flue and then is subjected to reduction reaction, so that the contact area and the contact time of the first reduction reaction are increased, and the sufficiency of the first reduction reaction is promoted.
The utility model discloses still including other subassemblies that can make the equipment normal use that reduces rotary kiln nitrogen oxide and discharge, like the water supply subassembly of being connected with the atomizer, the aqueous ammonia supply subassembly of being connected with the spray gun, the pressurization subassembly that gas distribution pipe or atomizer are connected etc. are the conventional technological means in this field. In addition, the utility model discloses in all adopt the conventional technical means in this field with limited device or subassembly, for example spray gun, atomizer, shower nozzle, first coal injection pipe, second coal injection pipe etc. all adopt the conventional technical means in this field.
The working principle of the utility model is that, the primary reduction reaction is carried out on the tail gas of the rotary kiln by the coal powder sprayed out from the second coal injection pipe and the reducing gas generated by insufficient combustion in the flue, after the tail gas of the rotary kiln which is subjected to the primary reduction reaction enters the decomposing furnace, the tail gas of the rotary kiln is mutually matched through the atomizing mechanism and the first coal injection pipe, not only the reducing gas such as carbon monoxide is formed, but also hydrogen is generated, so that a carbon monoxide and hydrogen distribution area with certain concentration is generated in the decomposing furnace, the secondary reduction reaction is carried out on the tail gas of the rotary kiln, the effect of the secondary reduction reaction of the tail gas of the rotary kiln is improved, and the concentration of nitrogen oxide contained in the tail gas of the rotary; then after various gases enter a main combustion area of the decomposing furnace, the gases are fully contacted with oxygen under the action of an air inlet pipe to be combusted, the gases are converted into pollution-free gases, finally, various gases enter a spraying area, ammonia water is sprayed to the gases through a spray gun, and nitrogen oxides in the gases are finally removed and converted.
The utility model has the advantages of simple and reasonable structure, and can effectively reduce the content of nitrogen oxide in the flue gas by carrying out multiple reduction reactions in the decomposing furnace, thereby reaching the national emission standard, saving energy and protecting environment; firstly, the tail gas of the rotary kiln is subjected to primary reduction reaction with the reducing gas generated by insufficient combustion of a second coal injection pipe in a flue, then the tail gas enters a decomposing furnace and is subjected to secondary reduction reaction, an atomizing mechanism and the first coal injection pipe are matched in the secondary reduction reaction, reducing gases such as carbon monoxide are formed, hydrogen is generated, a carbon monoxide and hydrogen distribution area with certain concentration is generated in the decomposing furnace, the effect of the secondary reduction reaction of the tail gas of the rotary kiln is improved, the concentration of nitrogen oxides contained in the tail gas of the rotary kiln after the secondary reduction is greatly reduced, various gases enter a main combustion area of the decomposing furnace and are fully contacted with oxygen under the action of an air inlet pipe for combustion and are converted into pollution-free gases, and finally various gases enter a spraying area, and an ammonia water is sprayed to the gases by a spray gun at the moment to finally remove and convert the nitrogen oxides in the gases, the dosage of ammonia water and the escape of ammonia gas are reduced.
Drawings
The present invention will be further explained with reference to the drawings and examples.
FIG. 1 is a schematic structural diagram of an apparatus for reducing nitrogen oxide emissions of a rotary kiln in the present embodiment;
fig. 2 is a schematic structural diagram of the atomizing mechanism in fig. 1.
In the figure: 1. the rotary kiln comprises a rotary kiln, 2 parts of a smoke chamber, 3 parts of a flue, 4 parts of a reduction zone, 5 parts of a main combustion zone, 6 parts of a spraying zone, 7 parts of a second coal spraying pipe, 8 parts of a first coal spraying pipe, 9 parts of an air distribution ring, 10 parts of an atomizer, 11 parts of an air inlet pipe, 12 parts of a spray gun, 13 parts of a pipeline, 14 parts of a spray head, 15 parts of a fixing piece.
Detailed Description
The present invention will be described more clearly with reference to the accompanying drawings and specific embodiments in the embodiments of the present invention, and the description herein is only for explaining the present invention, but not for limiting the present invention. Based on the embodiments of the present invention, any modifications, equivalent replacements, improvements, etc. made by other embodiments obtained by those skilled in the art without creative efforts should be included in the protection scope of the present invention.
Examples
As shown in fig. 1-2, the utility model provides a device for reducing the emission of nitrogen oxides in a rotary kiln, which comprises a decomposing furnace, wherein the decomposing furnace is sequentially divided into a spraying area 6, a main combustion area 5 and a reduction area 4 from top to bottom, and the bottom of the reduction area 4 is communicated with a smoke chamber 2 of the rotary kiln 1 through a flue;
the diameter of the spraying area 6 is smaller than that of the main combustion area 5, so that gas is more concentrated in the spraying area 6, the spraying range is reduced, the spraying effect is facilitated, the spraying area 6 is communicated with a spray gun 12, ammonia water is sprayed on the gas in the spraying area 6, the ammonia water is contacted with tail gas, the reduction reaction of the last step is carried out, and the nitrogen oxides in the tail gas are fully reacted into pollution-free gas;
the upper part of the reduction zone 4 is in a conical shape with a narrow top and a wide bottom, which is beneficial to slowing down the speed of the gas in the reduction zone 4 entering the main combustion zone 5 and prolonging the reduction reaction time of the reduction zone 4, the lower part of the reduction zone 4 is in an inverted cone shape with a wide top and a narrow bottom, the upper part of the reduction zone 4 is communicated with an air inlet pipe 11, oxygen contained in the air introduced into the air inlet pipe 11 and the gas in the reduction zone 4 enter the main combustion zone 5 together, the complete combustion of all the gases in the main combustion zone 5 is promoted, and the discharge of various harmful gases is avoided; an atomizing mechanism and a plurality of first coal injection pipes 8 are arranged at the lower part of the reduction zone 4, the atomizing mechanism comprises an atomizer 10, an air distribution ring 9 and spray heads 14, a mist outlet of the atomizer 10 is connected with a pipeline 13, the pipeline 13 is communicated with the air distribution ring 9, the air distribution ring 9 is fixed on the outer wall of the lower part of the reduction zone through a fixing part 15, the spray heads 14 are fixed on the inner wall of the lower part of the reduction zone and are uniformly distributed along the circumferential direction of the inner wall, the air inlet end of the spray heads 14 is communicated with the air distribution ring 9, and the first coal injection pipes 8 are distributed below the atomizing mechanism and are uniformly distributed along the circumferential direction of the lower part of the reduction zone; the atomizer 10 atomizes water entering the atomizer 10, the atomized water enters the gas distribution ring 9 through a pipeline 13, and then is uniformly sprayed and swept into the lower part of the reduction zone 4 through a spray head 14, and is evaporated and gasified in high-temperature flue gas, and a carbon monoxide and hydrogen distribution area with certain concentration is formed by matching with pulverized coal sprayed by a first coal injection pipe 8, and nitrogen oxides in tail gas of a rotary kiln in a decomposing furnace are converted into pollution-free nitrogen through the reduction gas;
the flue 3 is a smooth arc-shaped pipe, a second coal injection pipe 7 is arranged in the middle of the flue 3, and the second coal injection pipe 7 is communicated with the first coal injection pipe 8 to form the same coal feeding mechanism. The incomplete combustion of the pulverized coal sprayed by the second coal injection pipe 7 and the nitrogen oxide in the tail gas of the rotary kiln carry out the first reduction reaction, the arc-shaped pipe structure of the flue 3 improves the smoothness of the tail gas entering the decomposing furnace, increases the time and the distance of the first reduction reaction, and promotes the reduction effect of the first oxidation reduction.
The coal injection direction of the first coal injection pipe 8 is not intersected with the central axis of the reduction zone, the radial angle of the first coal injection pipe deviating from the reduction zone is 10-30 degrees, and the coal powder injected into the bottom of the reduction zone is insufficiently combusted at the position to generate more reducing gas, so that the entering tail gas of the rotary kiln and the reducing gas can be subjected to secondary reduction reaction again, and the nitrogen oxides of the tail gas are sufficiently reduced.
The coal injection direction of the second coal injection pipe 7 of the flue 3 is parallel to the central axis of the smoke chamber 2 of the rotary kiln 1. The rotary kiln tail gas in the second coal injection pipe 7 and the flue 3 is more sufficient due to the arrangement of the position, the coal powder sprayed by the second coal injection pipe is not sufficiently combusted due to long-time contact, and the generated reductive gas is subjected to contact reaction with the rotary kiln tail gas for the first time in the flue 3 and then enters the decomposing furnace to continue the reduction reaction, so that the contact area and the contact time of the first reduction reaction are improved, and the sufficiency of the first reduction reaction is promoted.
When the rotary kiln tail gas combustion device works, the tail gas of the rotary kiln 1 is subjected to primary reduction reaction with the reducing gas generated by insufficient combustion of the second coal injection pipe 7 in the flue, then enters the decomposing furnace and is subjected to secondary reduction reaction, the atomizing mechanism and the first coal injection pipe 8 are matched in the secondary reduction reaction, atomized water drops are mixed with the flue gas, atomized water is evaporated and gasified in high-temperature flue gas, coal powder is contacted with water vapor at high temperature to form reducing gas such as carbon monoxide and generate hydrogen, so that a carbon monoxide and hydrogen distribution area with certain concentration is generated in the decomposing furnace, the effect of the secondary reduction reaction of the tail gas of the rotary kiln 1 is improved, the concentration of nitrogen oxides contained in the tail gas of the rotary kiln after secondary reduction is greatly reduced, and various gases are sufficiently contacted with oxygen for combustion under the action of the air inlet pipe 11 after entering the main combustion area 5 of the decomposing furnace, the gas is converted into pollution-free gas, and finally various gases enter the spraying area 6, and the spray gun 12 sprays ammonia water on the gas, so that nitrogen oxides in the gas are finally removed and converted, and the consumption of the ammonia water and the escape of ammonia gas are reduced.
The foregoing description of the embodiments of the invention has been presented for purposes of illustration and not limitation, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the illustrated embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (3)
1. The equipment for reducing the emission of nitrogen oxides in the rotary kiln comprises a decomposing furnace and is characterized in that: the decomposing furnace is sequentially divided into a spraying area, a main combustion area and a reduction area from top to bottom, and the bottom of the reduction area is communicated with a smoke chamber of the rotary kiln through a flue;
the diameter of the spraying area is smaller than that of the main combustion area, and the spraying area is communicated with a spray gun;
the upper part of the reduction zone is in a conical shape with a narrow upper part and a wide lower part, the lower part of the reduction zone is in an inverted cone shape with a wide upper part and a narrow lower part, the upper part of the reduction zone is communicated with an air inlet pipe, the lower part of the reduction zone is provided with an atomizing mechanism and a plurality of first coal injection pipes, the atomizing mechanism comprises an atomizer, an air distribution ring and spray heads, a mist outlet of the atomizer is connected with a pipeline, the pipeline is communicated with the air distribution ring, the air distribution ring is fixed on the outer wall of the lower part of the reduction zone through a fixing part, the spray heads are fixed on the inner wall of the lower part of the reduction zone and are uniformly distributed along the circumferential direction of the inner wall, and an air inlet; the first coal injection pipes are distributed below the atomizing mechanism and are uniformly distributed along the circumferential direction of the lower part of the reduction zone;
the flue is a smooth arc-shaped pipe, a second coal injection pipe is arranged in the middle of the flue, and the second coal injection pipe and the first coal injection pipe are communicated with the same coal feeding mechanism.
2. The apparatus for reducing nitrogen oxide emissions of a rotary kiln as recited in claim 1, wherein: the coal injection direction of the first coal injection pipe is not intersected with the central axis of the reduction zone.
3. The apparatus for reducing nitrogen oxide emissions of a rotary kiln as recited in claim 1, wherein: and the coal injection direction of the second coal injection pipe on the flue is parallel to the central axis of the rotary kiln.
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CN202020213092.2U CN211575912U (en) | 2020-02-26 | 2020-02-26 | Equipment for reducing emission of nitrogen oxides in rotary kiln |
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