CN111006508A - Cement production line low-nitrogen decomposing furnace and cement production line low-nitrogen denitration technical method - Google Patents

Cement production line low-nitrogen decomposing furnace and cement production line low-nitrogen denitration technical method Download PDF

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CN111006508A
CN111006508A CN201911066124.9A CN201911066124A CN111006508A CN 111006508 A CN111006508 A CN 111006508A CN 201911066124 A CN201911066124 A CN 201911066124A CN 111006508 A CN111006508 A CN 111006508A
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decomposing furnace
furnace
production line
cone
nitrogen
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李志强
张宗见
周金波
轩红钟
孔取和
张东升
刘永涛
张提提
邵明军
杨旺生
邢超
范警卫
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Anhui Conch Construction Materials Design Institute Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B17/00—Furnaces of a kind not covered by any preceding group
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/76—Gas phase processes, e.g. by using aerosols
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B7/00—Hydraulic cements
    • C04B7/36—Manufacture of hydraulic cements in general
    • C04B7/43—Heat treatment, e.g. precalcining, burning, melting; Cooling
    • C04B7/44—Burning; Melting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D99/00—Subject matter not provided for in other groups of this subclass
    • F27D99/0001—Heating elements or systems
    • F27D99/0033—Heating elements or systems using burners

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Abstract

The invention discloses a cement production line low-nitrogen decomposing furnace and a cement production line low-nitrogen denitration technical method, wherein the decomposing furnace comprises two upper coal injection ports and four lower coal injection ports; the two upper burners and the horizontal plane form an included angle of 25-35 degrees, enter the decomposing furnace and are symmetrically arranged; four lower burners, horizontally tangentially into the decomposing furnace, and arranged approximately symmetrically. The invention designs the denitrification reducing area on the cone part of the decomposing furnace, thereby increasing the combustion space. While ensuring the coal powder to be fully combusted, the coal powder feeding ratio of the conical part of the decomposing furnace is properly increasedFor example, a reducing atmosphere generated by oxygen-deficient combustion is ensured; a reduction zone is formed at the cone part of the decomposing furnace to reduce a large amount of NO in the tail flue gas of the kilnxAnd good denitration effect is generated. After the technical scheme is implemented, the NO at the outlet of the preheater is finally enabledxThe concentration is reduced to 550mg/Nm3Hereinafter, the comprehensive denitration efficiency is 50% or more.

Description

Cement production line low-nitrogen decomposing furnace and cement production line low-nitrogen denitration technical method
Technical Field
The invention belongs to a cement clinker production line for reducing NOxThe technical field of emission denitration, in particular to a cement production line low-nitrogen decomposing furnace and a cement production line low-nitrogen denitration technical method.
Background
The cement is an important prop industry of national economy, the total output of the Chinese cement industry shows a rapid growth situation in nearly two decades due to the needs of economic development, and 1681 cement production lines are accumulated by novel dry-process cement production lines in China as the end of 2018, and the actual clinker yield exceeds 20 hundred million tons. The rapid development of the urbanization process and the economy does not depart from the contribution of the cement industry, but brings considerable environmental problems, and the cement industry becomes a key control object of energy consumption and air pollution due to huge yield.
Main atmospheric pollution of cement industryThe substance comprises NOxParticulate matter, SO2Etc. of Nitrogen Oxides (NO)x) Is one of the air pollution sources, causes harm to human bodies, can form acid rain, photochemical smog, ozone layer loss and secondary conversion into particles, seriously influences the national economic development and the normal life of people, and issues a series of laws and regulations for the national and local governments to limit NOxAnd (4) discharging.
GB4915-2013 discharge Standard of atmospheric pollutants for Cement industry, the NOx discharge concentration of general areas is controlled to be less than or equal to 400mg/Nm3And the control of NOx in key areas is less than or equal to 320mg/Nm3And local government environmental protection departments also issue local regulations and regulations to strictly control pollutant emission, for example, in Jiangsu, Shandong, Henan, Zhejiang and other areas, 100mg/Nm is implemented3Controlling the index requirements, and implementing peak shifting production in Shandong, Hebei, Shanxi, Anhui, Jiangsu, Zhejiang and other areas in order to control pollution.
NOXMechanism of formation of
Calcination of cement clinker at high temperature with NOXThe production routes mainly comprise thermal type, fuel type and rapid NOxAnd the like:
(1) "thermal type" NOXN being air2NO produced by oxidation at high temperaturesXThe production amount mainly depends on the temperature, the production is hardly carried out below 1350 ℃, and the production is carried out in large quantities above 1500 ℃, because the temperature of the burning zone flame in the rotary kiln is up to above 1500 ℃, and N in the air2And O2Fast reacting, thermal NOxAre produced in large quantities.
Figure RE-GDA0002326045680000021
Figure RE-GDA0002326045680000022
Figure RE-GDA0002326045680000023
The amount of the formed product is related to the combustion temperature, the oxygen concentration, the residence time in the high-temperature zone and the like.
(2) "Fuel type" NOxThe nitrogen compound in the fuel is generated by thermal decomposition and oxidation during combustion. N and NH in the volatile3See FIG. 5.
(3) "fast" NOx, which is N in air2With hydrocarbon radicals (CH, CH) in the fuel2Etc.) NO rapidly formed in the vicinity of the reaction zonexIt is produced in a small amount, generally in total NOxLess than 5%. Rapid NOxSee FIG. 6.
Since combustion is NOxThe main reason for the generation and the basic method for treating the same are mainly established according to the characteristics of the combustion process, in general, NOxThe treatment method can be divided into three methods of treatment before combustion, improvement of combustion mode and treatment after combustion. The pre-combustion treatment mainly comprises the steps of denitrifying the fuel; the improvement of the combustion mode is that low nitrogen oxide combustors, staged combustion and other low nitrogen combustion technologies are adopted; the treatment after combustion mainly refers to flue gas denitration technology which mainly comprises selective non-catalytic reduction technology (SNCR), selective catalytic reduction technology (SCR) and the like.
The basic principle of staged combustion denitrification is to establish a reduction combustion area between a smoke chamber and a decomposing furnace, uniformly distribute part of coal for the original decomposing furnace into the area, and ensure that the coal is subjected to anoxic combustion so as to generate CO and CH4、 H2And reducing agents such as HCN and fixed carbon. These reducing agents react with NO in the kiln tail flue gasxReaction takes place to convert NOxReduction to N2And the like, and inert gas without pollution. In addition, the pulverized coal is burnt under the anoxic condition, so that the self-fuel NO is inhibitedxThereby realizing the NOx emission reduction in the cement production process. The main reaction is as follows:
2CO+2NO→N2+2CO2
2H2+2NO→N2+2H2O
2NHi+2NO→N2+…
according to the characteristics and advantages of a cement process, a low-nitrogen decomposing furnace combustion denitration technology is adopted, the generation amount of NOx is controlled at the source starting from the process characteristics of a cement firing system, the purpose of NOx emission reduction is achieved, the method is a technical measure which is practical, economic, effective, energy-saving and environment-friendly at present, and has high feasibility and important research, popularization and implementation values.
Disclosure of Invention
Based on the technical current situation, the invention makes full use of the technical characteristics of the cement burning system to redesign the spraying position and the burning form of the fuel fed into the decomposing furnace, so as to ensure that the fuel generates reducing atmosphere in the cone of the decomposing furnace by anoxic burning and the thermal NO generated in the reducing furnacexAnd the aim of improving the denitration effect is fulfilled. Meanwhile, in order to avoid the generation of adverse phenomena such as material collapse and high-temperature skinning, the kiln tail smoke chamber, the uptake flue, the C4 blanking point, the tertiary air inlet and the like are modified and optimized, the problems existing in the application of the conventional staged combustion technology are solved, and the system is ensured to achieve a better denitration effect and a better operation effect.
In order to achieve the aim, the invention provides a cement production line low-nitrogen decomposing furnace, wherein two upper coal injection ports are symmetrically arranged on a cylinder at the upper part of the decomposing furnace, and four lower coal injection ports are symmetrically arranged on a cone at the lower part of the decomposing furnace; the decomposing furnace is provided with six burners in total, and comprises: the two upper burners and the horizontal plane form an included angle of 25-35 degrees and enter the decomposing furnace, and the two upper burners are symmetrically arranged on the horizontal cross section of the decomposing furnace; four lower burners entering the decomposing furnace horizontally and tangentially and arranged approximately symmetrically on a horizontal cross section of the decomposing furnace.
Preferably, the horizontal cross section of the kiln tail uptake flue below the decomposing furnace is square, and the height is 1500-.
Preferably, an R280-330mm cambered-surface material raising boss is arranged at the junction of the cone of the decomposing furnace and the kiln tail ascending flue.
Preferably, the cone of the decomposing furnace is also symmetrically provided with two spread boxes of C4 cyclones.
Preferably, the cross section of the side part of the material scattering box is conical, the bottom surface of the material scattering box forms an included angle of 20-35 degrees with the horizontal plane, and the blanking angle of the material scattering box forms an included angle of 55-60 degrees with the horizontal plane.
Preferably, the distance from the intersection point of the central line of the scattering box and the lower side wall to the cone inlet of the decomposing furnace is 200-1100 mm.
Preferably, the effective volume from the lower burner of the cone part of the decomposition furnace to the inlet of the tertiary air pipe is 100-3。
The invention also provides a low-nitrogen denitration technical method for the cement production line, which comprises the following steps: the coal powder which is led to the kiln tail is divided into two paths by a first coal powder distributor, wherein one path leads to a cylinder at the upper part of the decomposing furnace, and the other path leads to a cone at the lower part of the decomposing furnace; the coal powder which is led to the cylinder at the upper part of the decomposing furnace is divided into two paths by a second coal powder distributor and symmetrically enters the cylinder at the upper part of the decomposing furnace; the pulverized coal led to the cone at the lower part of the decomposing furnace is divided into two paths by the third pulverized coal distributor, and then divided into four paths by the coal dividing valve to symmetrically enter the cone at the lower part of the decomposing furnace, wherein the decomposing furnace is the decomposing furnace described above.
Preferably, the amount of the coal dust entering the cylinder of the decomposing furnace accounts for 0-20% of the total coal dust amount of the kiln tail, and the two paths of coal dust entering the cylinder at the upper part of the decomposing furnace are equal.
Preferably, the amount of the coal dust entering the cone at the lower part of the decomposing furnace accounts for 80-100% of the total coal dust at the tail of the kiln, and the four paths of coal dust entering the cone at the lower part of the decomposing furnace are equal.
In the technical scheme, the denitrification reduction area is designed on the cone part of the decomposing furnace, and the pulverized coal of the decomposing furnace is fed in an upper layer and a lower layer at 4 points, so that the combustion space is increased. The feeding proportion of the pulverized coal in the conical part of the decomposing furnace is properly increased while the pulverized coal is fully combusted, so that the reducing atmosphere generated by anoxic combustion is ensured; the decomposing furnace is provided with six burners, two upper burners and four lower burners, a reduction area is formed in the cone part of the decomposing furnace, and a large amount of NO in tail flue gas of the reducing furnacexAnd good denitration effect is generated. After the technical scheme is implemented, the NO at the outlet of the preheater is finally enabledxThe concentration is reduced to be less than 550mg/Nm3, and the comprehensive denitration efficiency is more than 50%.
The technology combines the process characteristics of a novel dry kiln system in the cement industry, and achieves the purpose of reducing NO by reforming the staged combustion technology of the decomposing furnacexThe purpose of discharging. Through research and comparison of a low-nitrogen combustion technology and a flue gas denitration technology, the technology is considered to be combined with the process characteristics of a cement clinker production line, and the technology which is preferentially modified by adopting a staged combustion technology has the following technical advantages:
① reduction and reduction of thermal NO produced in the kiln in conjunction with process operationxInhibiting the generation of fuel type NOx and effectively reducing NO from the sourcexGeneration of (1);
② has no secondary pollution and no pollutant or by-product;
③ has no adverse effect on the normal production and operation of the production line and the production and quality of the cement clinker;
④ it does not need to consume ammonia water or urea, and does not increase the production and operation cost;
⑤ the process is improved, so that the operation parameters are optimized, the system operation quality and stability are improved, and a certain energy-saving effect is achieved.
Through the improvement and operation debugging of the staged combustion technology of the phoenix building material 4500t/d production line, the denitration effect of the invention is found to reach the design target value, and the main implementation effect is as follows:
the denitration effect of the staged combustion technology is obvious, NOxThe emission reduction efficiency is more than 60 percent on average (particularly, the denitration efficiency of a production line with a large furnace volume of a decomposing furnace is more obvious), and the production and the quality of cement clinker are not influenced after the improvement;
the problem of skinning at the positions of a denitration reduction area, a kiln tail smoke chamber, a decomposing furnace and the like is effectively solved and avoided, and the normal and stable operation of a denitration system and a clinker production system is ensured;
the improvement effect of the refractory materials of the kiln tail smoke chamber uptake flue and the decomposing furnace lower cone is good, the phenomenon of material collapse is not easy to generate, the ventilation in the kiln is easier to stabilize, the kiln tail negative pressure is reduced, the fluctuation range is reduced, and the kiln condition is more stable than that before the improvement.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a sectional view of a decomposition furnace according to an embodiment of the present invention;
FIG. 2 is a plan view of a burner of a decomposition furnace modified by a staged combustion technique;
FIG. 3 is a flow chart of a staged combustion technology retrofit process;
FIG. 4 is a basic structure diagram of a spread box at the lower part of a C4 cyclone.
FIG. 5 shows "fuel type" NOxN and NH in the volatile3Schematic diagram of the oxidation pathway of (a);
FIG. 6 shows a rapid NO modexSchematic representation of the formation route of (1).
Description of the reference numerals
1 cylinder 2 cone
3 upper burner 4 lower burner
5 kiln tail uptake flue 6 lifting material boss
7C 4 cyclone lower part sprinkling box 8 tertiary air pipe
9C 4 cyclone upper material box 10 first coal powder distributor
11 second pulverized coal distributor 12 third pulverized coal distributor
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
In the present invention, unless otherwise specified, the directional words "upper, lower, side, bottom" and the like included in the terms merely represent the orientation of the terms in a conventional use state or are colloquially understood by those skilled in the art, and should not be construed as limiting the terms.
As shown in figures 1-4, the invention provides a low-nitrogen decomposing furnace for a cement production line, wherein a cylinder 1 at the upper part of the decomposing furnace is symmetrically provided with two upper coal injection ports, and a cone 2 at the lower part of the decomposing furnace is symmetrically provided with four lower coal injection ports; the decomposing furnace is provided with six burners in total, and comprises: the two upper burners 3 form an included angle of 25-35 degrees with the horizontal plane and enter the decomposing furnace, and the two upper burners 3 are symmetrically arranged on the horizontal cross section of the decomposing furnace; four lower burners 4, said lower burners 4 entering the decomposing furnace horizontally tangentially, and four lower burners 4 being arranged approximately symmetrically on the horizontal cross section of said decomposing furnace. Therefore, a denitrification reducing area is designed on the cone part of the decomposing furnace, and the pulverized coal of the decomposing furnace is fed in an upper layer and a lower layer by 4 points, so that the combustion space is increased. The feeding proportion of the pulverized coal in the conical part of the decomposing furnace is properly increased while the pulverized coal is fully combusted, so that the reducing atmosphere generated by anoxic combustion is ensured; the decomposing furnace is provided with six burners, two upper burners 3 and four lower burners 4, a reduction zone is formed in the cone part of the decomposing furnace, a large amount of NOx in the tail flue gas of the kiln is reduced, and a good denitration effect is achieved. After the technical scheme is implemented, the concentration of NOx at the outlet of the preheater is finally reduced to be less than 550mg/Nm3, and the comprehensive denitration efficiency is more than 50%.
In a preferred embodiment of the invention, the horizontal cross-sectional shape of the kiln tail uptake 5 below the decomposing furnace is square and the height is 1500-. The flue gas entering the decomposing furnace from the kiln tail smoke chamber is rectified, the shape of the uptake flue 5 is transformed into a square shape, and meanwhile, the straight section of the uptake flue is prolonged, so that the flow field of the flue gas entering the furnace in the kiln is stable, and the speed of the flue gas entering the furnace is reduced.
In a preferred embodiment of the invention, a cambered material-raising boss 6 with the thickness of R280-330mm is arranged at the junction of the cone of the decomposing furnace and the kiln tail uptake flue 5. The cambered surface material raising platform is designed at the joint of the ascending flue and the cone part of the decomposing furnace, so that the material collapse phenomenon is prevented, and simultaneously, the mixing of raw materials and air flow is easy.
In a preferred embodiment of the invention, the cone of the decomposing furnace is also symmetrically provided with two lower powder boxes 7 of C4 cyclone. According to the position condition of a C4 cyclone blanking point of an original firing system, the position of the C4 cyclone blanking point is adjusted by combining with the sectional heat load calculation data of a cone part of a reconstructed decomposing furnace, the C4 cyclone blanking is generally moved downwards to the cone part, raw materials absorb heat in the cone part, the high-temperature skinning phenomenon of the cone part of the decomposing furnace is avoided, the C4 material distribution amount is generally 30-60%, and a 20-35-degree spreading plane is built in a spreading box 7 at the lower part of the C4 cyclone by using pouring materials. In a preferred embodiment of the invention, the lateral section of the C4 cyclone lower powder box 7 is conical, the bottom surface of the C4 cyclone lower powder box 7 forms an included angle of 20-35 degrees with the horizontal plane, and the blanking angle of the C4 cyclone lower powder box 7 forms an included angle of 55-60 degrees with the horizontal plane. The raw materials slide down along the inner part of the cone part 2 of the decomposing furnace, and the high-temperature skinning phenomenon of the cone part 2 of the decomposing furnace is avoided.
In a preferred embodiment of the invention, the distance from the intersection point of the central line of the C4 cyclone lower material box 7 and the lower side wall to the cone inlet of the decomposing furnace is 200-1100 mm. Further avoiding the high-temperature skinning phenomenon of the cone part 2 of the decomposing furnace.
In a preferred embodiment of the invention, the effective volume of the lower burner 4 of the cone part of the decomposition furnace to the inlet of the tertiary air duct 8 is 100-3. Adjusting the area of a tertiary air inlet and the furnace entering speed according to the requirements of the tertiary air furnace entering speed and the flow field distribution of the original system; in operation, properly reducing the ventilation and coal feeding amount in the kiln, increasing the tertiary air quantity and the coal feeding amount of the decomposing furnace, reducing the excess air coefficient in the kiln as much as possible, and reducing the generation amount of NOx; the rotating speed of the high-temperature fan is reduced, the air consumption of the system is reduced as much as possible, the heat consumption of clinker sintering is reduced while the denitration efficiency is ensured, and the system resistance is reduced. After the staged combustion is improved, the ventilation volume in the kiln can be reduced, the tertiary air volume is relatively increased, the size of the tertiary air inlet needs to be redesigned in order to ensure that the air speed of the tertiary air inlet is about 18-22m/s, and in addition, the position of the tertiary air can be properly adjusted in order to ensure a sufficient reduction space of a cone part.
The invention also provides a low-nitrogen denitration technical method for the cement production line, which comprises the following steps: the coal dust led to the kiln tail is divided into two paths by a first coal dust distributor 10, wherein one path leads to a cylinder 1 at the upper part of the decomposing furnace, and the other path leads to a cone 2 at the lower part of the decomposing furnace; the coal powder which is led to the cylinder 1 at the upper part of the decomposing furnace is divided into two paths by the second coal powder distributor 11 and symmetrically enters the cylinder 1 at the upper part of the decomposing furnace; the pulverized coal introduced into the cone 2 at the lower part of the decomposing furnace is divided into two paths by the third pulverized coal distributor 12, and then divided into four paths by the coal dividing valve, and symmetrically enters the cone 2 at the lower part of the decomposing furnace, wherein the decomposing furnace is the decomposing furnace described above. Wherein the coal powder has the trend shown in figure 3.
The production process of the clinker: the materials prepared according to a certain proportion are fed from the top of a preheater, enter a decomposing furnace after being preheated by a multi-stage cyclone, are decomposed and then enter a rotary kiln for calcination, and then enter a grate cooler for cooling, and finally the clinker needed by people is obtained. The specific denitration process system is shown in fig. 3 and comprises a decomposing furnace, a burner, a rotary kiln and a preheater; the preheater is connected with the rotary kiln and the decomposing furnace, and comprises a primary cyclone cylinder, a secondary cyclone cylinder, a tertiary cyclone cylinder, a quaternary cyclone cylinder and a quintuplet cyclone cylinder.
In a preferred embodiment of the invention, the amount of the coal dust entering the cylinder 1 of the decomposing furnace accounts for 0-20% of the total coal dust at the tail of the kiln, and the two paths of coal dust entering the cylinder 1 at the upper part of the decomposing furnace are equal.
In a preferred embodiment of the invention, the amount of the coal dust entering the cone 2 at the lower part of the decomposing furnace accounts for 80-100% of the total coal dust at the tail of the kiln, and the four paths of coal dust entering the cone 2 at the lower part of the decomposing furnace are equal.
The present invention is NO which is different from the previous fractional combustionxThe emission reduction technology has the main innovation points of the technical scheme of the invention:
(1) redesigning the spraying position and the combustion form of the fuel fed into the decomposing furnace, forming a denitrification reducing area without generating crusting on the cone part of the decomposing furnace, mainly shaping the space of the reducing area, and reasonably arranging the position and the angle of a combustor to avoid generating local high temperature and crusting.
(2) Rectifying the airflow of the cement kiln tail ascending flue so as to enable the flow field of the ascending airflow to be smoother;
(3) the material raising jump table is arranged at the junction of the kiln tail rising flue and the cone part of the decomposing furnace, so that falling raw materials can be better dispersed, and the raw materials are prevented from directly entering the kiln and generating a local high-temperature area.
The key equipment (technology) development of the technology is as follows:
① kiln tail coal powder conveying and distributing technology, because the number of the decomposing furnace burners is 6, and the coal feeding amount of the 6 burners is designed differently, the requirement of the coal injection amount of the burners needs to be met through the design of the coal powder pipeline, which is mainly realized through a coal powder distributor, and the pipe diameter and the wind speed (30m/s) of the coal powder pipeline are specially designed;
② A technology for creating a reducing zone of a decomposing furnace is crucial, the technology divides kiln tail coal dust into 6 points by redesigning the position of a burner of the decomposing furnace, the upper layer and the lower layer enter the kiln tail coal dust, and the speed, the position, the angle, the cut-in angle and the like of the coal dust entering the decomposing furnace directly influence the combustion form of the coal dust in the decomposing furnace and the formation quality of the reducing zone, the reducing zone is mainly generated by combusting the coal dust sprayed by 4 burners at the lower layer under the anoxic condition, thereby playing the role of reducing and denitrating NOx generated in the kiln;
③ rectification technology of kiln tail flue gas, which is to develop a stable production and high efficiency decomposition furnace fuel staged combustion technology, wherein the stability of the system of the pre-decomposition kiln is directly influenced by the phenomena of whether the technology is stable or not, whether the phenomena of skinning and the like occur or not, the technology rectifies the kiln tail flue gas mainly through the transformation of a kiln tail flue chamber uptake flue and a material lifting lug boss, thereby keeping the system stable;
④ C4 divides the material and spills the magazine in lower part, guarantees that the material smoothly reaches the pulverized coal burning trend, avoids producing high temperature crust, and the inside is built 20-35 inclination through the castable, guarantees to spill the material effect.
The system is technically characterized in that a reduction zone is effectively constructed in the decomposing furnace, and unfavorable factors such as reduction zone skinning are avoided by reforming a kiln tail smoke chamber, an ascending flue and a conical part of the decomposing furnace, so that a good operation effect is achieved.
Through carrying out graded combustion technology transformation and operation debugging on the phoenix building material 4500t/d production line, the denitration effect reaches a design target value, and the main implementation effect is as follows:
the denitration effect of the staged combustion technology is obvious, NOxThe emission reduction efficiency is about 60 percent on average (particularly, the denitration efficiency of a production line with a large furnace volume of a decomposing furnace is more obvious), and the production and the quality of cement clinker are not influenced after the improvement;
the problem of skinning at the positions of a denitration reduction area, a kiln tail smoke chamber, a decomposing furnace and the like is effectively solved and avoided, and the normal and stable operation of a denitration system and a clinker production system is ensured;
the improvement effect of the refractory materials of the kiln tail smoke chamber uptake flue and the decomposing furnace lower cone is good, the phenomenon of material collapse is not easy to generate, the ventilation in the kiln is easier to stabilize, the kiln tail negative pressure is reduced, the fluctuation range is reduced, and the kiln condition is more stable than that before the improvement.
The device is used for 2000 t/d-12000 t/d clinker line projects of a novel dry kiln.
In the present invention, the C4 is generally short for the C4 cyclone cylinder, i.e. the fourth stage cyclone cylinder, by those skilled in the art. The kiln head and the kiln tail are also the kiln head or the kiln tail of the rotary kiln.
The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims (10)

1. The low-nitrogen decomposing furnace for the cement production line is characterized in that a cylinder (1) at the upper part of the decomposing furnace is symmetrically provided with two upper coal injection ports, and a cone (2) at the lower part of the decomposing furnace is symmetrically provided with four lower coal injection ports;
the decomposing furnace is provided with six burners in total, and comprises:
the two upper burners (3) form an included angle of 25-35 degrees with the horizontal plane and enter the decomposing furnace, and the two upper burners (3) are symmetrically arranged on the horizontal cross section of the decomposing furnace;
four lower burners (4), said lower burners (4) entering the decomposition furnace horizontally tangentially, and the four lower burners (4) being arranged approximately symmetrically on the horizontal cross section of said decomposition furnace.
2. The cement production line low-nitrogen decomposing furnace as claimed in claim 1, wherein the horizontal cross-sectional shape of the kiln tail uptake (5) below the decomposing furnace is square and the height is 1500-.
3. The cement production line low-nitrogen decomposing furnace as claimed in claim 1, wherein a cambered material-raising boss (6) with the thickness of R280-330mm is arranged at the junction of the cone part of the decomposing furnace and the kiln tail uptake flue (5).
4. The cement production line low-nitrogen decomposing furnace according to claim 1, characterized in that the cone of the decomposing furnace is further symmetrically provided with two C4 cyclone lower discharging boxes (7).
5. The cement production line low-nitrogen decomposing furnace as claimed in claim 4, characterized in that the side section of the C4 cyclone lower hopper (7) is conical, the bottom surface of the C4 cyclone lower hopper (7) forms an angle of 20-35 degrees with the horizontal plane, and the blanking angle of the C4 cyclone lower hopper (7) forms an angle of 55-60 degrees with the horizontal plane.
6. The cement production line low-nitrogen decomposition furnace as claimed in claim 5, wherein the distance from the intersection point of the center line of the sprinkle box (7) and the lower side wall to the cone inlet of the decomposition furnace is 200-1100 mm.
7. The cement production line low-nitrogen decomposition furnace as claimed in claim 1, wherein the effective volume from the lower burner (4) of the cone of the decomposition furnace to the inlet of the tertiary air duct (8) is 100-180m3。
8. A low-nitrogen denitration technical method for a cement production line is characterized by comprising the following steps:
the coal dust led to the kiln tail is divided into two paths by a first coal dust distributor, wherein one path leads to a cylinder (1) at the upper part of the decomposing furnace, and the other path leads to a cone (2) at the lower part of the decomposing furnace;
the coal powder which is led to the cylinder (1) at the upper part of the decomposing furnace is divided into two paths by a second coal powder distributor and symmetrically enters the cylinder (1) at the upper part of the decomposing furnace;
the coal powder which is led to the cone (2) at the lower part of the decomposing furnace is divided into two paths by a third coal powder distributor, then divided into four paths by a coal dividing valve and symmetrically enters the cone (2) at the lower part of the decomposing furnace,
wherein the decomposition furnace is the decomposition furnace according to any one of claims 1 to 7.
9. The denitration technique of claim 8, wherein the amount of the pulverized coal entering the column (1) of the decomposing furnace accounts for 0-20% of the total amount of the pulverized coal at the tail of the kiln, and the amounts of the two paths of pulverized coal entering the column (1) at the upper part of the decomposing furnace are equal.
10. The denitration technique of claim 8, wherein the amount of the pulverized coal entering the cone (2) at the lower part of the decomposing furnace accounts for 80-100% of the total amount of the pulverized coal at the tail of the kiln, and the amounts of the four paths of pulverized coal entering the cone (2) at the lower part of the decomposing furnace are equal.
CN201911066124.9A 2019-11-04 2019-11-04 Cement production line low-nitrogen decomposing furnace and cement production line low-nitrogen denitration technical method Pending CN111006508A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111750683A (en) * 2020-07-07 2020-10-09 天津水泥工业设计研究院有限公司 Decomposing furnace zone-tissue combustion self-denitration system and process capable of adjusting oxygen concentration of reduction zone
CN112058064A (en) * 2020-09-23 2020-12-11 南京凯盛国际工程有限公司 Circulating spouting NOx emission reduction system and working method thereof
CN112679121A (en) * 2020-12-28 2021-04-20 安徽海螺集团有限责任公司 Cement clinker production line with low emission and low energy consumption
CN114777471A (en) * 2022-05-07 2022-07-22 金华亨泰工程技术有限公司 Energy-saving denitration method for coal powder injection of rotary cement kiln decomposing furnace

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111750683A (en) * 2020-07-07 2020-10-09 天津水泥工业设计研究院有限公司 Decomposing furnace zone-tissue combustion self-denitration system and process capable of adjusting oxygen concentration of reduction zone
CN111750683B (en) * 2020-07-07 2021-04-23 天津水泥工业设计研究院有限公司 Decomposing furnace zone-tissue combustion self-denitration system and process capable of adjusting oxygen concentration of reduction zone
CN112058064A (en) * 2020-09-23 2020-12-11 南京凯盛国际工程有限公司 Circulating spouting NOx emission reduction system and working method thereof
CN112679121A (en) * 2020-12-28 2021-04-20 安徽海螺集团有限责任公司 Cement clinker production line with low emission and low energy consumption
CN114777471A (en) * 2022-05-07 2022-07-22 金华亨泰工程技术有限公司 Energy-saving denitration method for coal powder injection of rotary cement kiln decomposing furnace
CN114777471B (en) * 2022-05-07 2023-09-01 金华亨泰工程技术有限公司 Energy-saving and denitration coal dust spraying method for rotary cement kiln decomposing furnace

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