Vertical grinding production technical knowledge

Date: 2019-07-01 Views:

First, the structure of the raw material vertical grinding

Raw material vertical grinding (hereinafter referred to as vertical grinding) is used for raw material grinding. Since the raw material contains moisture,

Therefore, the vertical mill should have the dual functions of grinding and drying. The vertical mill consists of the following parts:

1.1 compartment wheel feeding device

1.2 Mill body

1.3 Mill drive system

1.4 Separator and its transmission

1.5 Mill maintenance tools

1.6 Equipment walking and railings

1.7 Hydraulic and lubrication systems

1.8 Mill Drive and Control Electrical System

1.9 Water spray system

Second, the operation of raw material grinding

1. Preparation before grinding

1.1. Inform the inspection workers to check and confirm the system equipment. 1.2. Check whether the material level of each bin in the batching station is normal, and inform the driver and the reclaimer to organize the feeding according to the position. 1.3. Inform the electrician and the patrolman to perform the “three-to-one” work. 1.4. Check whether the temperature, pressure and flow rate of each measuring point are normal. 1.5. Check the charging voltage and current of the kiln tail electricity collection, and whether the electric field works normally. 1.6. Notify the quality schedule to set the ratio of raw materials and determine the proportion of each material. 1.7. Inform the total drop and dispatch to prepare for grinding.

2. Normally open after large overhaul

The rotary kiln has been fed and the feeding capacity is more than 300 tons/hour. The operation is stable, the kiln tail electric dust collection system and the humidification tower system have been put into operation, and the kiln tail system fan runs smoothly. When the residual heat and heat run smoothly, the exhaust gas from the kiln exhaust gas may not pass through the humidification tower system, and the exhaust gas discharged from the high temperature fan of the preheater may be directly ground.

2.1, start the homogenization library top group; 2.2, start the raw material delivery group;

2.3, notify the inspection workers will return the ash into the kiln to return to the ash storage

2.4. Inform the inspection worker to check the sealing fan, start the sealing fan, and observe whether the pressure is normal; (At present, the sealing fan and 618 start chain are still not released)

2.5, start the grinding roller thin oil station, observe whether the pressure, temperature, flow is normal;

2.6. Start the main thin oil station and observe whether the pressure, temperature and flow are normal. 2.7 Start the hydraulic tensioning station and observe whether the pressure, temperature and flow are normal. 2.8 Set the speed of the vertical mill to 800 rpm. The powder selection machine; after the operation is stable, gradually adjust its rotation speed;

2.9. Close the inlet baffle of the vertical mill circulating fan and start the fan. After the fan runs smoothly, gradually adjust the opening degree of the inlet baffle and the outlet baffle to maintain the proper negative pressure of the grinding outlet. According to the temperature of the grinding outlet, gradually open the hot air. The baffle plate maintains the negative pressure of the grinding inlet and is baked according to the heating curve of the mill;

2.10. Start the grinding machine feeding group; observe whether the starting current of each equipment is within a reasonable range. If there is any abnormality, promptly confirm the site. 2.11. Start the vertical grinding slag group;

2.13, notify the company to dispatch, total drop, electrician, grinding and inspection, on-site inspection whether the grinding roller rises, start the grinding main motor;

2.14. When the mill outlet temperature is greater than 90 °C, start the raw material feeding group and set the proportion of the ingredients according to the requirements of the laboratory;

2.15. Increase the exhaust volume of the vertical mill circulating fan, increase the amount of ventilation inside the mill, adjust the opening degree of the hot air baffle and the opening degree of the circulating air baffle to keep the negative pressure of the grinding mill less than 1600 Pa. Simultaneously adjust the fan baffle opening degree of the kiln tail system to ensure that the negative pressure at the outlet of the vertical mill circulating fan is within the normal range;

2.16, set the grinding pressure equal to 80bar, when the mill differential pressure is greater than 4500 Pa, carry out the roller grinding; if the differential pressure reaches 5500Pa, the grinding pressure can be appropriately increased.

2.17. Start the water spray device of the mill to spray water on the material in the mill. The first spray is set to 3t/h, and the water spray amount in the mill can be adjusted according to the outlet temperature of the mill;

2.18. Monitor the vibration value of the mill and the thickness of the mill layer, and prepare the lifting roller at any time;

2.19. When the thickness of the material layer exceeds 100mm, the grinding pressure is increased, but the pressurization is not allowed to exceed 5 bar/time. After the vibration of the mill is stable, the slag silo should be drained first, and the production can be appropriately reduced before the slag is discharged. Keep in touch with the site and control the reasonable cutting speed (calculated by the current of the circulating bucket) to avoid the instability of the grinding.

2.20. When the current of the slag bucket is reduced and the thickness of the material layer is thinned, it can be properly added. The production should not exceed 10 tons per time, and the time interval should be greater than 10 minutes. When the slag bucket current increases, it should be Increase the internal ventilation of the mill, increase the opening degree of the vertical mill circulating fan, and increase the speed of the separator;

2.11. When the grinding pressure reaches 110 bar, the pressure shall not exceed 2 bar/time for each additional grinding pressure, and the pressure interval shall be greater than 15 minutes. Whenever the pressure is not allowed to exceed 114 bar;

2.22. During normal operation, the speed of the classifier is not allowed to exceed 1230 rpm.

3. Stop grinding

(1) Stop grinding for more than 8 hours: (The grinding needs to be heated for 2 hours and kept for 30 minutes)

1.1. Inform the patrolman to prepare for the empty limestone silo, iron raw material silo, sandstone silo and clay silo;

1.2. Inform the kiln and the power generation operator to make corresponding preparations, notify the inspection workers, the laboratory, the total drop, and the dispatching preparations to stop grinding;

1.3. Stop the limestone storage group 2.5 hours before stopping the grinding;

1.4. 2 hours before the stoppage, notify the joint storage warehouse to control the level of each allocated warehouse to ensure that the warehouse is empty after 2 hours;

1.5. When the blanks of each warehouse are not smooth, notify the inspection workers to carry out the warehouse work. After the air is pulled out, stop the raw material blending group; (closely pay attention to the material on the grinding belt, the thickness of the grinding disc layer, the vibration of the mill, in advance Carry out the roll operation to prevent abnormal vibration of the vertical mill); 1.6, in order to control the vertical mill vibration, first reduce the production operation, when the vertical grinding slag amount decreases, reduce the friction inside the mill, reduce the speed of the classifier, when the mill When the temperature is high, the hot air baffle can be closed and the wind temperature can be controlled. When the thickness of the disc layer is gradually reduced, the grinding pressure can be reduced. When the thickness of the grinding disc material is less than 50mm, the grinding pressure is reduced to 90bar, and the slag is discharged to the slag silo;

1.7. After the material on the grinding belt is finished, stop the main motor of the raw material grinding; at the same time, close the hot air baffle, open the bypass baffle, and close the circulating air baffle. Close the inlet baffle and outlet baffle of the vertical mill circulating fan, stop the circulating fan; stop the classifier at the same time, when the grinding outlet temperature is lower than 60 °C, and then stop the power-off procedure and confirm the power failure, then the grinding door can be opened. Control the internal pressure of the mill;

1.8. After stopping the grinding, the wind should be kept as stable as possible, and the temperature of the high-temperature fan outlet should be ensured. At the same time, the temperature of the dust-collecting gas entering the kiln tail should be ensured. When the dust-collecting temperature of the kiln is more than 150 °C, the dust-collecting cold-air baffle can be properly opened.

1.9. Inform the inspection worker to check the material conveying condition of the main chute. When the transportation is completely cleaned, notify the kiln operation, and return the ash to the kiln, and stop the raw material conveying group after 1 minute;

1.10, stop the top group of raw materials;

1.11. After the main motor is stopped for 2 hours, stop the hydraulic station and place the grinding roller on the grinding disc. When the grinding main motor is stopped for more than 4 hours, the vertical grinding roller lubrication and the main thinning oil station can be stopped;

1.12. Stop the ventilation fan after stopping the ventilation for 4 hours. (2) Stop grinding for more than 4 hours: (If you need to heat up for 1 hour, keep warm for 20 minutes)

2.1. Notify the site to stop feeding to each bin of the batching station at the appropriate time;

2.2, stop the feeding group, stop the grinding water spray group, after the lifting roller, the three-way valve baffle is driven into the slag silo;

2.3, stop grinding the main motor, open the bypass baffle, cold air baffle, gradually reduce the hot air baffle, open the 1618 fan inlet baffle;

2.4. Stop the slag recycling group. The lifting roller is more than 15 minutes, and the main motor is stopped for less than 2 hours: (in the middle of the insulation, if you need to enter the grinding inspection, heat up quickly, keep warm for 10 minutes)

(3) Inform the kiln and the power generation operator to make corresponding preparations, notify the inspection workers, the laboratory, the total drop, and the dispatching preparations to stop grinding; (4) Stop the loading of each warehouse in due course.

(5), stop material, stop spraying water, lifting roller, stop 1327 and classifier.

(6) Keep the operation of each thin oil station, lubrication station, hydraulic station, sealing fan, raw material conveying group and storage group, and roll down on site.

(7) If you do not enter the grinding inspection, close the grinding and grinding baffles for heat preservation (if you need emergency inspection, first report the branch leader and production scheduling), you can close the hot air baffle and open the inlet. The cold air baffle and the grinding outlet baffle are ground for cold grinding. However, all inlet and outlet hot air baffles must be closed when grinding. (8) Lifting roller within 15 minutes: Stop the raw material mixing group; Stop spraying the water inside the grinding; Turn off the small circulating fan inlet baffle to control the internal temperature of the grinding; If the lifting roller exceeds 15 minutes, stop the main motor. It takes a long time to process the problem, and the circulating fan is stopped for more than 30 minutes.

Third, the maintenance of raw material grinding

If the vertical inspection is done better, the vertical grinding can reduce the number of downtimes and improve the equipment operation rate. Vertical mill is a large-scale equipment, and the cost per start is relatively high. If the fault is eliminated without grinding, the maintenance cost can be saved, and the equipment operation rate can be greatly improved. Therefore, it is particularly important to reduce the number of stoppages, save maintenance costs, and find equipment failure points as early as possible. This requires daily inspections, and daily inspections have the following precautions.

1, cooling water

Whether it is groundwater or river water, it will contain a certain amount of sediment. Over time, it will easily deposit at the filter of the lubrication station of the reducer and block the filter. Once the filter is clogged, it will further increase the oil temperature and even damage the equipment. Therefore, the cooling water needs to check the return water condition and cleanliness during production, and check 2-4 times per shift.

2. Inspection of each temperature measurement point

The temperature measurement point of the vertical mill is 20-30. Since the vertical mill is always in the state of vibration during production, even if it runs smoothly, there is a certain amount of vibration, which is easy to loosen the wiring of the thermal resistor, which may cause wiring. Bad, inaccurate signals, etc. Therefore, when the control system displays a large deviation between the number and the usual time, it needs to be checked at any time to confirm whether the signal is accurate.

3, sealed fan

The main function of the sealing fan is to keep the grinding roller in a positive pressure state, so as to prevent the powder from entering the inside of the grinding roller during production, and play the role of protecting the grinding roller bearing. There must be a certain amount of dust in the air. If the sealing fan blows the dust into the inside of the grinding roller, it may damage the grinding roller bearing, damage the skeleton seal, and cause the grinding roller to leak oil. This requires a filter screen in the air inlet of the fan to block the entry of dust.

4, the classifier

The powder selection machine is the main control equipment for the quality of the vertical mill. Only the stable operation of the powder separator can better control the product quality. For the working characteristics of the classifier, we should pay attention to the following aspects: First, check the shaft temperature of the classifier. Because the working environment of the classifier is between 90-95 degrees, it is easy to cause the bearing temperature to be too high: Check the rotor wear and handle it if it is worn.

5, roller sleeve and disc liner

The vertical grinding roller sleeve is made of composite material surfacing, and the service life is generally between 3000h-4000h. If it is run for 24h all day, it needs to be surfacing once every 5-6 months. Regular inspection of the roll sleeve and the disc liner is not only to arrange the build-up cycle, but more importantly to check whether the wear is normal, and to detect the abnormal situation in time.

6, accumulator

The pressure of the accumulator is about 50% of the working pressure according to the actual situation. Due to various factors such as the wearability, moisture content and particle size of the materials, the working pressures used by the plants are different. The pressure of the accumulator can be adjusted according to the actual working pressure. Seasonal changes and seal failures also affect the accumulator pressure, which requires one month to check the accumulator pressure.

7, lubrication pipeline

The lubrication line is a very important part of the lubrication system. It is also a place where the fault is more likely to occur. If the pipeline leaks in a short practical way, all the oil in the tank is emptied. The place where the pipeline fails is the interface and the weld. Location, timely detection of leaks has become an important part of daily inspections.

8, the choice of oil quality

There are also high-quality oils in the pipeline, and many users now use ordinary lubricants, mineral oil. However, according to the design principle of vertical mill, it is best to use synthetic gear lubricants, and there is a big difference between the two. The most obvious benefit of synthetic gear oil under normal conditions is that the grinding roller returns to a low temperature. The normal lubricating oil return temperature is 10 degrees higher than that of synthetic lubricating oil at 50 degrees or above. It can be seen that the quality of the oil plays a vital role in the use of the equipment.

9, the replacement of lubricating oil

The use of high-quality lubricants should also be replaced in time. Lubricants are usually replaced once in the first 1-2 months, and then replaced every six months. In the first oil change, it is best to cycle the pipeline again and clean the tank. The main reason for this is that, due to the use, the bonding iron scraps of the wall in the pipeline will fall under the pressure of high pressure, and the pipeline can be cleaned cleanly by one cycle.

10, grease lubrication point inspection

Grease lubrication is a very important part of vertical grinding. In order to avoid excessive oil or insufficient lubricant in the production process. Too much grease treatment: First check the control cabinet to set the oil supply time is too long: secondly, the nozzle is blocked or not tightened. In order to prevent the amount of lubricating oil from being insufficient, in the daily inspection, it is necessary to pay attention to whether there is abnormal sound or abnormal wear during operation of the equipment. This phenomenon is likely to occur at the earring of the cylinder. If the lubrication is insufficient here, It is easy to cause the cylinder pin to move inflexibly, and even cause the cylinder earring to break.

11, the fastening of the bolt

There are dozens of bolts in the vertical mill. These bolts are tightened and loosened during the test run, running 8h or the first feeding stop. In order to avoid loose or loose bolts, all bolts need to be checked during daily parking inspection to avoid The bolts are off and cause a major accident. The following is an example of the importance of the bolts using the rocker arm and the bolt on the grinding roller as an example.

Loose bolts on the rocker arm can cause the following problems

1) The rocker spindle is tilted. The main reason for this phenomenon is that the bolt at one end of the rocker main shaft is loose, and the bolt at the other end is still fastened, so that the main force of the rocker arm is asymmetrical, that is, it is biased toward the other end.

2) The pin set is deformed. The set of books is also symmetrically installed. When the other end is loose and the other end is fastened, the set of the load will be asymmetrical and slight deformation will occur. This phenomenon is not felt during normal operation and can only be found when the rocker arm is removed.

3) The rocker seal frame is detached. Seal frame bolt length

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