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Operation and Management knowledge of New Energy-saving 5000t/d Raw material Vertical Mill

Date:2019-07-02 10:21 Source:未知Views:

First, the guiding ideology of operation


1. With the close cooperation of all professionals and field inspectors, according to the moisture, particle size, differential pressure, inlet and exit temperature, system air volume and so on, the feed quantity and baffle opening of the mill should be adjusted in time, so as to make the vertical mill run smoothly and improve the grinding efficiency.

2、Establish the concept of "safety in production, quality first", careful operation, continuous summary. According to the actual situation of production, make full use of advanced technical means such as metering and monitoring instruments, computers and other advanced technical means to determine the best operating parameters, to achieve high quality, stable production, high efficiency, low consumption, long-term safe and civilized production.

II. Preparation before grinding


1. Notify PLC personnel to put DCS into operation.

2. Inform the total drop to be prepared for the upper load.

3. Inform the electric personnel to transmit power to the unprepared equipment.

4. Notify the QCX personnel and the dispatcher to be ready for power-on.

5. Inform the on-site inspector to do the inspection before starting and keep close contact with it.

6. Interlock inspection, for those who do not meet the operating conditions, it is necessary to find the relevant personnel to deal with.

7. Check whether the baffle and gate valve are in the central control position and whether the action is flexible and reliable. If the central control display is consistent with the field display, if not, find the relevant personnel to correct.

8. Check the material position of each warehouse in the batching station.

9. Check the group chart to start the program: where there is red, indicating that there is an alarm or does not meet the starting conditions, should find out the reasons one by one to deal with, until the red clear.

III. Operation management of open mill operation of hot-blast stove

1. Baking mill


Contact the site to confirm that there should be a suitable oil level in the diesel fuel shortage tank. If it is the first grinding of the new grinding, the drying time should be long, generally about 2 hours, and the heating rate should be slow and stable, and the grinding outlet temperature should be controlled at about 80 ℃ 90 ℃. Start the kiln tail EP fan before heating up, close the air valves on both sides of the kiln, adjust the EP fan, grind the outlet and inlet baffle, and slightly increase the exhaust air after ignition. After the hot blast furnace is lit, the suitable air volume and temperature can be achieved by adjusting the fuel supply, compressed air pressure and cold air baffle of primary and secondary fans. In view of the fact that raw material powder is collected by electric dust collection at the end of the kiln, when the hot blast stove is ignited, the electricity at the end of the kiln is collected. The dust cannot be charged, and after the fire is ignited, the oil can be fully combusted, and no CO is generated, at this time, the electric dust collection of the kiln tail can be charged.

2、 Cloth


When the hot blast stove is used for the first time, manual laying should be carried out on the grinding disk. The specific methods are:

(1) The material can be fed into the mill through a three-way air valve from an inlet grinding belt, and then the material is paved in the mill.

(2) evenly spreading the material directly from the mill door to the mill. After the material is paved, the grinding disc is driven to be slow to rotate by the auxiliary driving motor, and then the paving is carried out, so that the grinding disc is repeated several times. So as to ensure that the material in the material bed is compacted, the material layer is stable, and the thickness of the final material layer is controlled at about 80-100 mm. At the same time, it is also necessary to make the cloth to the grinding belt. The method comprises the following steps of: firstly, selecting a "Cancel the interlock with the main motor" selection item, and then starting a mill feeding; taking into account that the air volume and the heat are low when the hot air is used for grinding and grinding, the amount of the cloth can be controlled to be about 120 to 140 t/ h, the speed of the grinding belt is operated at 25 percent, Stop.

3. Grinding operation


When the mill is fully preheated, it can be ready to start grinding. Before starting the mill and feeding, it should be confirmed that the dust transportation and auxiliary equipment of the mill are in normal operation, the water resistance of the mill has been stirred, and the auxiliary clutch has been closed. After issuing the starting command to the grinding main motor, feeding and slag spitting group, the auxiliary power transmission opportunity first drives the grinding disc to rotate for 1 minute and 58 seconds. At this time, the valve baffle of EP fan at the end of the kiln is increased to about 60 ≤ 70% to ensure that the negative pressure of the grinding outlet is controlled at about 5500~6500Pa, the outlet valve is fully open, and the first hot air valve baffle at the entrance is fully closed, and the second hot air baffle and cold air valve are gradually opened. If the circulating air valve of the system should be fully open, the belt should be put into operation after the main motor is started, and the belt speed can be set at 65 ≤ 75%. Considering that the hot air volume of the hot blast furnace is less, the feed quantity of the grinder can be controlled around 250~300t/h, and the fuel supply and air supply volume of the hot blast furnace should be increased synchronously. Through the adjustment of the primary and secondary air of the hot blast furnace, the flame combustion of the hot blast furnace can be stable and sufficient.

Because it takes nearly 10 seconds to enter the grinding belt from zero speed to normal running speed, the short time material in the grinding machine is less, which is manifested in the fact that the current of the grinding main motor decreases to a very low current, the thickness of the material layer decreases, the vibration is large, and the treatment is not timely will lead to the vibration jump and stop of the mill. At this time, the following measures can be taken to solve the problem:

The main results are as follows: (1) 10 ≤ 20 seconds before starting of the main motor, the feed should be started, but the speed of the belt should be lower.

(2) the belt speed can be increased to about 85% at first, and then the belt speed can be reduced gradually after the mill is stable.

(3) the ventilation volume of the mill is reduced at the beginning of grinding, and then the ventilation volume of the mill increases gradually after the material layer of the mill is stable.

4. Normal system control


After the mill is in operation, special attention should be paid to the parameters such as the current of the main motor, the thickness of the material layer, the differential pressure of the mill, the temperature of the outlet gas of the mill, the vibration, the negative pressure of the inlet and outlet of the mill. The current of the mill main motor is 270-320 A, the thickness of the material layer is 80-100 mm, the differential pressure of the mill is between 5000 and 6000 Pa, the temperature of the mill outlet gas is 60-80 DEG C, the vibration is between 5.5 and 7.5 mm/ s, and the pressure of the tension station is 8.0-9.5 Mpa.

5. Shutdown


1. Stop the feeding program of each bin of the batching station, and if it is a long-term shutdown, prepare it ahead of time, so as to finish the materials of the batching plant as much as possible.

1. Stop grinding main motor, feeding and discharging group.

(3)Turn down the oil supply and air supply volume of the hot air furnace. If it is a long-term shutdown, extinguish the flame of the hot blast furnace, reduce the cold air valve of the EP fan at the kiln tail and the opening of the inlet valve of the mill to ensure a certain ventilation in the mill. IV. Grinding with waste gas at kiln tail(feed rate of kiln≥200t/h)1. Grinding.

When the waste gas from kiln tail is used to bake, the air valve on both sides is controlled at about 60%, the inlet and outlet valve is opened to ensure a certain hot air volume in the mill, the drying time is controlled at about 30 min / 60 min, and the outlet temperature is controlled at about 80 °90 ℃. If the grinding machine is broken down for a short time, it can be grinded directly. two。 Grinding operation

Before the grinding, master the working condition of the mill:

whether there is a proper thickness of material layer in the mill, whether there is enough material for the belt entering the mill, and if there is less material, it can be distributed in advance. Start the main motor of mill, mill feeding and slag discharge circulating group. After the group start command is issued, increase the inlet valve of EP fan at the kiln tail to about 85~95%, ensure that the negative pressure of the mill outlet is controlled at 65007500Pa, gradually close the two bypass valves to close, gradually open the mill outlet valve and two hot air valves until all open, and adjust the cold air valve to about 20%opening(to supplement the air volume). These valves shall be actuated before the main motor is started. . However, it is not suitable to move too early, which leads to the high temperature of the grinding outlet gas.

After the main motor, feeding and slag spitting circulation group is started, 65 ≤ 75% speed can be input into the grinding belt, the feed quantity can be controlled at about 340~380t/h, and the speed of the belt, the feed quantity, the rotating speed of the powder separator and the outlet baffle of the mill can be adjusted according to the amount of material in the mill when the grinding is just started, so that the condition of the mill is gradually close to normal. According to the temperature of the gas at the inlet and outlet of the mill, it is decided whether the water spraying system of the mill needs to be turned on. According to the different technological arrangement position of humidifying tower, the method of controlling grinding outlet temperature is also different when starting the mill. When the humidifying tower is located in front of the high temperature fan at the end of the kiln, due to the hot air intake. The water spray of the humidifying tower has been cooled, so the temperature of the air inlet and outlet gas is lower than about 250 DEG C, and the temperature of the corresponding mill inlet and outlet gas is also low. If the position of the humidifying tower is behind the high-temperature fan, the hot gas entering the mill is not cooled, and the temperature of the gas is about 310-340 DEG C. At this time, the water spray of the mill needs to be started to control the temperature of the mill outlet. 3. System Normal Control

Main parameters control:

the current of the mill main motor is 300-380A, the thickness of the material layer is 100-120mm, the differential pressure of the mill is 6500-7500Pa, the temperature of the mill outlet gas is 80-95 DEG C, the feeding amount of the mill is 380-450t/ h, the pressure of the tension station is 8.0-9.5 Mpa, and the vibration is between 5.5 and 7.5mm/ s. The normal operation of the mill is controlled mainly from the following aspects:

(1) Feed quantity of mill


In normal operation, the mill's output can be improved as much as possible under the premise of ensuring the quality of the raw material, and the adjustment range of the feeding amount can be determined according to factors such as the vibration of the mill, the outlet temperature, the system air volume, the differential pressure, and the like, and the amount of ventilation in the mill can be adjusted at the same time of increasing the feeding amount.

(2) Mill vibration


Vibration is an important parameter in the operation of the mill, which is the main factor that affects the yield and the running rate of the mill. The vibration is related to a number of factors, and the following points are noted from the point of view of the single-control operation:

A, the feed of the mill should be stable, the rate of increase and decrease should be small each time, and the speed of feeding and decreasing should be moderate.

B, to prevent the mill from breaking or uneven incoming materials. If the incoming material is suddenly reduced, the speed of the grinding belt can be increased and the grinding baffle can be turned off.

C, there are too many materials in the mill, especially too much powder, so it is necessary to reduce the belt speed and feed quantity in time, or reduce the speed of the powder separator, and strengthen the drawing air in the mill.

(3) differential pressure of mill


In operation, the stability of differential pressure is critical to the normal operation of the mill, which reflects the load of the mill. The change of the differential pressure mainly depends on the feeding quantity, the ventilation quantity and the mill outlet temperature of the mill. When the differential pressure is changed, check whether the blanking of the batching station is stable, and inform the relevant personnel after the fluctuation finds out the cause, and make proper adjustment. If the feeding is normal, the feed quantity, the ventilation quantity, the speed of the powder selection machine and the water spray quantity can be adjusted if the feeding is normal.

(4) Mill outlet temperature


The outlet temperature of vertical mill plays an important role in ensuring the qualified moisture of raw meal and the stability of mill. The outlet temperature is too high (> 95 ℃), the material layer is unstable, the vibration of mill is increased, and it is not conducive to the safe operation of the equipment. The outlet temperature is mainly controlled by adjusting the feed quantity, hot air valve, cold air valve, mill and humidification tower. (5) moisture and fineness of ground raw materials

The water control index of the raw material powder is 0.5%, so that the water content of the raw material powder can reach the standard, and the method can be solved by adjusting the hot air quantity and the water spraying amount of the grinding machine according to the feeding quantity, the temperature of the mill inlet and the outlet, the water content of the raw material entering the mill and the like. The fineness of the raw meal can be solved by adjusting the rotation speed of the powder selection machine, the ventilation quantity of the mill and the feeding quantity. If the fineness or water content exceeds the standard, it is necessary to analyze the cause and the corrective measures on the shift-over notebook.

4. Shutdown


When stopping normally, the main motor, feed and slag group can be stopped first, and the bypass air valve can be opened at the same time, the inlet of EP fan at the end of kiln can be adjusted, the outlet valve and inlet valve can be turned on, all the cold air valves can be opened, and the humidifying tower can be opened or increased to spray water. Stop the feeding of the relevant silo of the dispensing station.

Fifth, the operation of the mill after the failure stops the kiln.


In view of the fact that the output of most production plants is greatly affected by the supply of raw materials, in order to prolong the running time of grinding, the operation of grinding can be maintained after kiln shutdown. When the kiln system is shut down, due to the sudden decrease of hot air volume, the cold air valve should be opened in time, the baffle opening of EP fan should be properly reduced, the water spraying system should be stopped, the bypass air valve should be closed, and the feed quantity of the mill should be greatly reduced to about 250~300t/h, so as to ensure the stability of the mill. In order to prevent the air flow temperature of the high temperature fan at the end of the kiln from being too high, the inlet cold air valve of the high temperature fan can be properly opened. The inlet baffle of the high temperature fan can be carried out from small to small according to the outlet temperature and grinding temperature of the high temperature fan. Big adjustment. The inlet temperature of high temperature fan is below 450 ℃ and the grinding temperature is higher than 40 ℃. When the kiln system resumes feeding, it should be prepared and adjusted in time to avoid the impact of the sudden increase of hot air on the mill. That is to say, before feeding, the feed quantity of the mill can be slightly increased, the thickness of the material layer can be controlled, and the feeding quantity and belt speed of the kiln system can be increased rapidly to ensure the stability of the material quantity in the mill. According to the hot air volume, the water spray system can be gradually opened and the small cold air valve closed.

VI. Matters for attention


1. When there is an unknown reason in the operation of the mill, the mill shall be checked and confirmed, and the seal pressure of the mill, radial pressure of the 12 valve blocks of the reducer, the current of the material layer and the main motor shall be closely observed. In case of abnormal large-range fluctuation and alarm, immediately stop grinding and check the internal conditions of relevant equipment and mill to ensure the safe operation of the equipment.

2. The sealing and plugging of the system is strengthened. The air leakage of the system is not only the stable operation of the mill, but also has a great influence on the output of the mill. In particular to an electric dust collection zipper machine, an air pipe flange connection part, a three-way gate valve and the like.

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