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CN-122010433-A - Anti-skinning optimization method for denitrification furnace preheater system for cement production

CN122010433ACN 122010433 ACN122010433 ACN 122010433ACN-122010433-A

Abstract

The invention relates to the technical field of cement clinker calcination, in particular to an anti-skinning optimizing method of a denitrification furnace preheater system for cement production, which adopts the technical scheme that the anti-skinning optimizing method comprises the working flow of structural modification of an eccentric cone blanking pipe, firstly, the inner diameter of the eccentric cone blanking pipe is enlarged to 1200mm, so that the design flow is improved to 120% of the original level, the possibility of depositing harmful components is fundamentally reduced, the original components are replaced by adopting high-temperature resistant 304 stainless steel, a micro-crystal plate lining is laid on the pipe section below an expansion joint, the corrosion resistance and the anti-skinning performance of a pipeline are greatly improved, in addition, the inclination angle of the blanking pipe is calibrated to 22 degrees by a laser level meter, and the material accumulation height is monitored in real time by installing the laser range finder, so that the dynamic early warning of the risk of blocking is realized, the skinning problem caused by pipe diameter shortage and material aging is effectively solved, and meanwhile, the manual blocking clearing frequency is reduced.

Inventors

  • YANG HAIMING
  • YANG PENGFEI
  • ZHU XIANJUN
  • LI HONGRONG
  • CUI JUNJUN
  • KANG SHUJUN

Assignees

  • 陕西北元化工集团股份有限公司

Dates

Publication Date
20260512
Application Date
20260310

Claims (10)

  1. 1. A method for optimizing the anti-skinning performance of a denitrification furnace preheater system for cement production is characterized by comprising the following steps: s11, increasing the material passing capacity and monitoring the skinning state in real time by expanding the pipe diameter, replacing the high-temperature-resistant microcrystalline material lining and adding a pressure measuring device; s12, removing redundant pipelines, adjusting the position of a material scattering box, replacing a microcrystalline lining, integrating DCS by combining a pressure sensor, and performing visual control on the blanking efficiency and the working condition; S13, reconstructing the section shape and the flow guiding structure of the air outlet, adding an air cannon array, and matching with DCS pressure monitoring to eliminate local accumulation and uneven wind speed; S14, optimizing the inclination angle of the top plate and the material of the guide plate, expanding the ventilation sectional area, reducing the system resistance and improving the thermal stability; S15, replacing the straight nozzle with a fan-shaped nozzle, accurately arranging injection points, and efficiently cleaning a skinning area by combining electromagnetic valve control; S16, comprehensively replacing the high-temperature easy-skinning area with a microcrystalline plate, and prolonging the service life of equipment and reducing manual intervention through a staggered joint dry laying process and abrasion monitoring; s17, deploying a differential pressure transmitter and a three-level alarm mechanism, wherein data are directly connected with a DCS, and performing material blocking early warning and process parameter dynamic adjustment; s18, expanding the sectional area of a pipeline, optimizing flow field distribution, and combining a variable frequency fan with CFD simulation to ensure air volume balance and energy-saving operation of the system; and S19, establishing an operation database and an expert control system, and performing thermal system self-adaptive adjustment and capacity maximization through multi-parameter coupling analysis.
  2. 2. The method for optimizing the anti-skinning of a nitrogen removal furnace preheater system for cement production according to claim 1, wherein the method comprises the following steps of: s21, expanding the inner diameter of the eccentric cone blanking pipe from 1000mm to 1200mm, improving the material passing capacity to 120% of the design flow, keeping the pipe wall thickness to be 8mm and keeping the inner wall roughness to be less than or equal to Ra0.8; s22, removing the original flap valve and expansion joint, replacing the original flap valve and expansion joint with a high-temperature-resistant 304 stainless steel material, and testing the tightness, wherein the leakage quantity is less than or equal to 0.1L/mi under the pressure of 0.5 kPa; S23, laying a microcrystalline board on the inner wall of the pipe section 300mm below the expansion joint, wherein the thickness is 20+/-2 mm, the surface roughness is less than or equal to Ra0.4, and the joint is filled with high-temperature-resistant cement; S24, reserving a DN50 air cannon interface at the position 150mm above the expansion joint, and installing a high temperature resistant 316L stainless steel fan-shaped nozzle in a matched mode, wherein the injection angle is 60 degrees, and the flow coefficient Cv=5.0; s25, adjusting the inclination angle of the blanking pipe to be 22 degrees, adjusting the error of the included angle between the blanking pipe and the horizontal plane to be less than or equal to +/-1 degree, and detecting whether the self-flow speed of the material is more than or equal to 0.8m/S by adopting laser level meter calibration; S26, installing a laser range finder, monitoring the accumulation height of the blanking pipe material in real time, setting an alarm threshold value to be 70% of the pipe diameter, and acquiring data at a frequency of 1 time/second; and S27, using an endoscope for checking the abrasion condition of the pipe wall in a quarter, immediately replacing when the thickness of the microcrystal plate is abraded by more than 5mm, and recording the abrasion position and degree.
  3. 3. The method for optimizing the anti-skinning of the nitrogen removal furnace preheater system for cement production according to claim 1, wherein the method comprises the following steps: S31, cutting and dismantling a standby blanking pipe and a secondary distributing valve of the mixing chamber, welding a plugging plate with the thickness not less than 10mm, and performing 100% X-ray flaw detection after welding, wherein the defect rate is less than or equal to 1%; S32, moving the whole material scattering box of the denitration furnace upwards by 1000mm, adjusting the vertical distance between the material scattering point and the material separating valve to be 800mm, and adjusting the angle of the material scattering plate from 5 degrees to 25 degrees; S33, replacing the pipe section below a flap valve of a blanking pipe of the denitration furnace with a microcrystalline lining, controlling the joint width to be 2-3mm, setting the installation gap to be less than or equal to 3mm, and constructing by adopting a staggered joint dry laying method; S34, respectively installing 1 set of pressure sensor on the discharging pipes from the C4 to the decomposing furnace and the denitration furnace, measuring the pressure at 0-5000Pa, and accessing signals into a DCS system with the precision of +/-0.2 percent FS; s35, checking the torque of a flange connection bolt of the blanking pipe monthly to ensure that the pretightening force of an M16 bolt reaches 180 N.m, and checking by using a torque wrench; s36, purging the inner wall of the blanking pipe by using compressed air every week, controlling the pressure to be 0.6MPa, and maintaining the purging time for 3 minutes, wherein accumulated materials at joints are mainly cleaned; and S37, adjusting the deviation between the center line of the blanking pipe and the axis of the denitration furnace to be less than or equal to 5mm, and adopting a theodolite to perform three-dimensional space positioning calibration and detecting the centering accuracy.
  4. 4. The method for optimizing the anti-skinning of a nitrogen removal furnace preheater system for cement production according to claim 1, wherein the method comprises the following steps of: S41, changing the cross section of the air outlet of the tertiary air pipe from a phi 800mm round shape to a flat structure with the width of 1200mm and the height of 400mm, increasing the ventilation area by 40%, and controlling the air speed at 8-12m/S; S42, manufacturing a 45-degree chamfer at the bottom of the air outlet, wherein the chamfer radius R=100 mm, and adopting a numerical control plasma cutting machine for processing, wherein the surface roughness is less than or equal to Ra3.2; S43, dismantling an eccentric cone pressure measuring ring pipe, performing surface polishing treatment after welding and plugging, wherein the roughness reaches Ra1.6, and the sealing test pressure is 1.5 times of the design pressure; s44, symmetrically installing 2 air cannons at the 1/3 height position of the air outlet, wherein the distance between nozzles is 500mm, the adjustable range of the injection angle is +/-15 degrees, and the material is hastelloy C276; s45, detecting wind speed distribution of an air outlet every month, measuring at grid points of a cross section by using a hot wire anemometer, wherein the grid spacing is 200mm, and detecting whether the standard deviation of the wind speed is less than or equal to 0.5m/S; s46, changing an air outlet guide plate into a refractory castable prefabricated part with the thickness of 150mm, and baking and solidifying at 1100 ℃ after installation, wherein a baking curve is heated in three stages; S47, checking the accumulated material condition of the air outlet every time, starting an air cannon to clean when the thickness of the accumulated material exceeds 50mm, and recording the cleaning period to the DCS.
  5. 5. The method for optimizing the anti-skinning performance of a denitrogenation furnace preheater system for cement production according to claim 1, wherein the method comprises the following steps of: s51, changing an outlet top plate of the denitration furnace into a plate inclined at 30 degrees with a horizontal plane, adopting a laser cutting machine to process, enabling the groove angle error to be less than or equal to 1 degree, and performing PT detection after welding; S52, replacing a guide plate at the joint of the outlet and the mixing chamber with refractory castable, controlling the dimensional accuracy to +/-2 mm, setting the installation clearance to be less than or equal to 3mm, and curing for 72 hours after pouring; S53, replacing a metal winding gasket at the flange joint of the outlet pipeline, wherein the metal winding gasket is made of 304 stainless steel strips and flexible graphite, the compression ratio is controlled to be 15-20%, and the bolt pretightening force is uniform; S54, welding a wear-resistant lining plate at the elbow of the outlet pipeline, wherein the thickness is 8mm, the material is NM400 wear-resistant steel plate, and UT detection is carried out after welding, and the defect rate is less than or equal to 0.5%; s55, detecting the displacement of the expansion joint of the outlet pipeline every month, wherein the transverse displacement is less than or equal to 20mm, the axial displacement is less than or equal to 15mm, and monitoring in real time by using a displacement sensor; S56, an outlet pipeline heat-insulating layer adopts an aluminum silicate fiber blanket, the density is 200kg/m < 3 >, the thickness is 150mm, a 0.8mm aluminum plate protective layer is arranged outside, and the joint is sealed; and S57, carrying out outlet pipeline stress analysis in each quarter, adopting ANSYS software for modeling, detecting whether the maximum stress is less than or equal to 80% of the allowable stress of the material, and archiving analysis results.
  6. 6. The method for optimizing the anti-skinning of a nitrogen removal furnace preheater system for cement production according to claim 1, wherein the method comprises the following steps of: s61, replacing 27 straight nozzles at the inlet of the denitration furnace, the eccentric cone and other parts with fan-shaped nozzles, wherein the injection angle is adjusted to 60 degrees, the flow coefficient Cv=5.0, and the material is 316L stainless steel; S62, setting the pressure of an air cannon air storage tank to be 0.8MPa, providing an automatic drain valve, discharging condensed water 1 time per shift, and recording the water discharge to a log; S63, the error of the installation position of the nozzle is smaller than or equal to 10mm transversely and smaller than or equal to 5mm longitudinally, the nozzle is calibrated by a laser positioning instrument, and the spraying direction and the material flowing direction form an included angle of 30 degrees; s64, detecting the outlet flow rate of the nozzle every month, and detecting whether the flow rate is more than or equal to 200m/S or not and whether the flow rate deviation is less than or equal to +/-5% by using an anemometer at a position 100mm away from the nozzle; S65, adding 2 air cannons between the tertiary air pipe air outlet and the denitration furnace outlet, wherein the distance is 1500mm, the spraying direction is adjustable, and the material is silicon carbide ceramic composite; S66, respectively adding 1 air cannon at the eccentric cone straight section and the smoke chamber expansion joint, wherein the central line of the nozzle and the pipe wall form an included angle of 30 degrees, and the radius of coverage is more than or equal to 500mm; S67, adding 2 air cannons on the upper eccentric cone section of the mixing chamber, controlling by adopting an electromagnetic valve, controlling the response time to be less than or equal to 0.2 seconds, and linking the injection frequency with the material flow.
  7. 7. The method for optimizing the anti-skinning performance of a nitrogen removal furnace preheater system for cement production according to claim 1, wherein the method comprises the following steps of: S71, replacing the lining at the key part with a microcrystalline plate with the thickness of 25mm, wherein the flexural strength is more than or equal to 40MPa, and the temperature resistant range is less than or equal to 1200 ℃; S72, installing the microcrystalline board by adopting a staggered joint dry laying method, controlling the joint width to be 2-3mm, filling high-temperature-resistant cement, and enabling the temperature resistance of the cement to be more than or equal to 1300 ℃; s73, detecting the surface roughness of the microcrystal plate every month, measuring by using a portable roughness meter, detecting whether Ra is less than or equal to 0.4, and marking and replacing a worn area preferentially; s74, establishing a microcrystalline material abrasion file, recording the abrasion loss of each plate, and replacing when the thickness loss exceeds 30%, wherein a replacement period prediction model is incorporated into the DCS; S75, curing the microcrystalline board by adopting a steam curing process, controlling the temperature to be 50+/-5 ℃, controlling the humidity to be more than or equal to 95%, and curing for 72 hours, wherein the temperature is raised and lowered in three stages; S76, operators receive the training of the characteristics of the microcrystalline materials, grasp the indexes of thermal shock stability and corrosion resistance, and the training qualification rate is 100%; And S77, performing evaluation on the anti-skinning performance of the microcrystalline material in each quarter, and evaluating the result and performing assessment hook through the skinning thickness and cleaning frequency index quantification effect.
  8. 8. The method for optimizing the anti-skinning of the nitrogen removal furnace preheater system for cement production according to claim 1, wherein the method comprises the following steps of: S81, installing a differential pressure transmitter at the position 500mm above the flap valve, wherein the measuring range is 0-1000Pa, the precision is 0.1% FS, the signal is connected into a DCS system, and the response time is less than or equal to 0.5 seconds; s82, setting three-level alarm by the DCS, namely, setting the first-level alarm to be 500Pa, the second-level alarm to be 700Pa, and the third-level alarm to be 900Pa, and pushing alarm information to the mobile terminal; S83, calibrating the pressure measuring device every month, performing three-point calibration at the measuring range points of 0%, 50% and 100% by adopting a standard pressure source, wherein the error is less than or equal to 0.2% FS, and the calibration record is archived; S84, adopting a stainless steel pipe with phi of 12 multiplied by 2mm as a pressure measuring pipeline, setting a drain valve at the lowest point, recording the drain amount to a log, wherein the drain period is 1 time per day; s85, training an operator to grasp pressure trend analysis skills, judging the position of the plugging material through a pressure curve, wherein training content comprises case analysis and practical operation; s86, establishing a pressure data history database, wherein the sampling period is 1 second, the storage period is more than or equal to 1 year, and backing up data to a cloud server; s87, developing pressure data analysis software to realize the functions of blocking early warning and fault diagnosis, wherein the early warning accuracy is more than or equal to 95%, and the diagnosis report is automatically generated.
  9. 9. The method for optimizing the anti-skinning of a nitrogen removal furnace preheater system for cement production according to claim 1, wherein the method comprises the following steps of: s91, expanding the cross section of an outlet pipeline of the denitration furnace from 0.5m2 to 0.7m2, adopting a numerical control bending machine to process, wherein the ellipticity is less than or equal to 1%, and performing PT detection after welding, wherein the defect rate is less than or equal to 0.5%; s92, the ventilation area of the tertiary air pipe air outlet is increased to 1.2m < 2 >, the air speed is controlled to be 8-12m/S, the air quantity adjusting range is +/-10%, and the variable frequency fan is adopted for control; S93, the total ventilation quantity of the system is improved to 180000m < 3 >/h, a variable frequency fan is arranged to realize stepless regulation of the air quantity, the fan efficiency is more than or equal to 85%, and the noise is less than or equal to 85dB; s94, detecting system resistance monthly, measuring at a measuring point grid by using a Pitot tube, wherein the grid spacing is 500mm, detecting total resistance is less than or equal to 4500Pa, and the resistance distribution is uniform; s95, polishing the inside of the ventilating duct, wherein the surface roughness reaches Ra3.2, the adhesion of materials is reduced, cleanliness detection is carried out after polishing, and the residue of particles is less than or equal to 0.1g/m < 2 >; s96, installing an air quantity regulating valve, wherein the opening control precision is +/-2%, the air quantity of each branch is uniformly distributed, an electric actuator is adopted as an actuating mechanism of the regulating valve, and the response time is less than or equal to 2 seconds; S97, performing CFD flow field simulation in each quarter, optimizing pipeline layout, eliminating a low-speed vortex region, and comparing simulation results with actual measurement data, wherein the error is less than or equal to 5%.
  10. 10. The method for optimizing the anti-skinning of the nitrogen removal furnace preheater system for cement production according to claim 1, wherein the method comprises the following steps of: s1001, establishing an operation parameter database, recording key parameters of air quantity, temperature and pressure, sampling for 1 minute, storing data into the real-time database, and keeping historical data for more than or equal to 3 years; s1002, developing an expert control system, automatically adjusting operation parameters according to the composition of materials and the change of yield, wherein the adjustment amplitude is less than or equal to +/-5%, and the response time of the system is less than or equal to 30 seconds; S1003, carrying out thermal calibration in each month, measuring indexes such as thermal efficiency, unit energy consumption and the like of the system, wherein the thermal efficiency target is more than or equal to 85%, the unit energy consumption is less than or equal to 105kJ/kg, and submitting a calibration report to a management layer; S1004, an operator receives dynamic parameter adjustment training, grasps the skill of adjusting the feeding amount according to pressure change, wherein the training comprises simulation exercise and real operation examination, and the qualification rate is 100%; S1005, establishing a crust early warning model, and realizing early intervention through temperature, pressure and component multiparameter coupling analysis, wherein the early warning time advance is more than or equal to 1 hour, and the accuracy is more than or equal to 90%; S1006, carrying out system capacity test in each quarter, verifying the running stability under 120% load working condition, ensuring that the fluctuation range of key parameters is less than or equal to +/-3%, and archiving test reports; S1007, managing the targets with an advanced enterprise in industry, continuously improving operation rules and improving the reliability of the system.

Description

Anti-skinning optimization method for denitrification furnace preheater system for cement production Technical Field The invention relates to the technical field of cement clinker calcination, in particular to an anti-skinning optimization method of a denitrification furnace preheater system for cement production. Background In recent years, with the increase of the environmental protection policy of the country and the increase of the control force, stricter requirements are also provided for the emission of nitrogen oxides in all places, the ultra-low emission standard is continuously brought out for the country, in order to respond to the state call, the ultra-low emission project in industry is improved by the North-Shaanxi group cement Limited company, after the improvement, the denitrification furnace system is operated on the carbide slag production line for the first time, the problems of serious denitrification furnace crust, frequent eccentric cone blocking, more unplanned parking, low free calcium percent of pass and the like are successively generated in the operation process, the production cannot be stably operated, the problems cannot be solved from the operation adjustment, and the system is further optimized to be forced. The existing anti-skinning optimization method of the denitrification furnace pre-heater system has obvious defects in the aspects of pipeline design and material application, mainly comprises the steps of small diameter of an eccentric cone blanking pipe and unreasonable selection of refractory materials, wherein the inner diameter of the blanking pipe is only 1000mm, so that harmful components in carbide slag are easy to deposit in a pipeline to form skinning blocks, blocking is frequently caused, meanwhile, the common anti-skinning castable adopted by the inner wall cannot effectively resist corrosion of components such as sulfur and chlorine, and unplanned shutdown is caused by skinning and blocking of parts such as a flap valve and an expansion joint. Aiming at the problems that the existing denitrification furnace preheater system is obviously insufficient in the aspects of pipeline design and material application, the denitrification furnace preheater system is mainly characterized in that the diameter of an eccentric cone blanking pipe is smaller, the selection of refractory materials is unreasonable, the inner diameter of the blanking pipe is only 1000mm, harmful components in carbide slag are easy to deposit in a pipeline to form skinning blocks, blocking is frequently caused, meanwhile, the common skinning-resistant castable adopted by the inner wall cannot effectively resist corrosion of components such as sulfur and chlorine, and the like, the problems that the blanking pipe is not planned to stop due to skinning and blocking are solved, firstly, the inner diameter of the eccentric cone blanking pipe is enlarged to 1200mm, the material passing capability is obviously improved, the design flow is improved to 120% of the original level, the possibility of depositing harmful components is fundamentally reduced, secondly, the high-temperature 304 stainless steel is adopted to replace the original components, the lining of a microcrystalline plate is laid in the pipe section below the expansion joint, the corrosion resistance and the high-temperature-resistant glue filling joint are greatly improved, in addition, the problems of corrosion resistance and skinning-resistant performance of the pipeline are solved, the error-resistant pipe diameter is calibrated to 22 degrees by a laser level meter, the real-time performance is not improved, the problem of the real-time performance is also is remarkably improved, the problem of the error-time is solved, and the problem of the continuous material is not-aged due to the fact that the error-prone to the measurement is not is reduced, and the equipment is prone to be subjected to the problem of the measurement is due to the slope and is reduced. Disclosure of Invention In order to overcome the defect of obvious defects in the aspects of pipeline design and material application of the traditional anti-skinning optimization method of the denitrification furnace preheater system, the problems that the diameter of an eccentric cone blanking pipe is smaller, the selection of refractory materials is unreasonable, the inner diameter of the blanking pipe is only 1000mm, harmful components in carbide slag are easy to deposit in a pipeline to form skinning blocks, blocking is frequently caused, meanwhile, the common anti-skinning castable adopted by the inner wall cannot effectively resist corrosion of components such as sulfur, chlorine and the like, and the problems of unplanned stopping of parts such as flap valves, expansion joints and the like caused by skinning blocking are mainly solved. The invention adopts the technical scheme that the anti-skinning optimization method of the denitrification furnace preheater system for cem