One Reason: Excessive coal feeding to the coal mill

　　Phenomenon: 1. The grinding sound is low and the electric ear signal decreases. 2. The current of the coal mill suddenly decreases from high to low. 3. The pressure difference between the inlet and outlet of the coal mill increases

　　Solution: 1. Reduce the coal feeding rate and operate it for a period of time at a low coal feeding rate to eliminate coal accumulation in the mill. 2. Gradually increase the coal feeding rate to restore normal operation of the mill. 3. Stabilize the coal feeding rate to ensure normal operation

　　II Reason: Insufficient coal feeding to the coal mill

　　Phenomenon: 1. Grinding pitch, crisp sound 2. Grinding current decreases 3. Pressure difference between coal mill inlet and outlet decreases

　　Solution: 1. Gradually increase the coal feeding amount to restore the coal mill to normal. 2. Confirm whether the coal bunker is overhead

　　III Reason: Blockage in the grinding and drying chamber

　　Phenomenon: 1. Electric ear signal increases, grinding pitch, and sound becomes brittle. 2. Grinding pressure difference increases

　　Solution: 1. Check if the moisture content of the raw coal is high. If it is high, reduce the coal feeding amount appropriately. 2. Increase the inlet air temperature of the coal mill appropriately. 3. If the above measures have no significant effect, stop the mill for maintenance.

　　4 Reason: High temperature of spindle tile

　　Phenomenon: 1. High temperature indication. 2. Retrieve the temperature trend and confirm the rate of temperature increase

　　Solution: 1. Check the oil supply system, check if the oil supply pressure and temperature are normal, and adjust if they are not. 2. Check if there is water or other debris in the lubricating oil. 3. Check if the inlet air temperature is too high, and adjust if it is too high. 4. Check the cooling water system. 5. Determine if there is an instrument malfunction

　　Five Reason: The outlet gas temperature of the mill is too high

　　Phenomenon: 1. Too much hot air volume 2. Too small opening of the cold air valve at the coal mill inlet 3. Too little coal feeding volume

　　Solution: Adjust according to normal operation to balance the air and material

　　VI Reason: The outlet gas temperature of the mill is too low

　　Phenomenon: 1. Insufficient hot air volume 2. Excessive opening of cold air valve at the coal mill inlet 3. Excessive coal feeding 4. High moisture content in raw coal

　　Solution: Adjust according to normal operation to balance the air and coal

　　7 Reason: The gas temperature at the bag dust collection outlet is too high

　　Phenomenon: 1. Dust accumulation in the bag dust collector hopper 2. High hot air volume 3. Small opening of the cold air valve at the coal mill inlet

　　Solution: 1. Notify on-site ash removal. 2. Reduce the size of the hot air baffle. 3. Increase the opening of the cold air baffle

　　8 Reason: The negative pressure of the gas at the outlet of the coal mill is too high

　　Phenomenon: 1. The opening of the inlet valve of the coal mill exhaust fan is too large. 2. Grinding blockage

　　Solution: 1. Close the inlet valve of the mill exhaust fan. 2. Reduce the coal feeding amount and stop it if necessary

　　Nine Reason: The negative pressure of the gas at the outlet of the coal mill is too low

　　Phenomenon: 1. The opening of the inlet valve of the coal mill exhaust fan is too small. 2. The coal feeding amount is too small, resulting in an empty mill. 3. The coal feeder does not discharge. 4. The discharge chute is blocked

　　Solution: 1. Increase the exhaust fan valve. 2. Increase the coal feeding rate. 3. On site treatment. 4. Increase the opening of the main exhaust fan inlet baffle, close the cold air valve, and block it on site

　　Ten Reason: Decreased current in the powder selection machine

　　Phenomenon: 1. Insufficient system output 2. System blockage 3. Pin detachment between impeller and shaft

　　Solution: 1. Adjust the output to a higher level. 2. Adjust the system output to clear the blocked area. 3. Stop the coal mill system and contact maintenance for assistance

　　Eleven Reason: Large differential pressure between bag dust collection inlet and outlet

　　Phenomenon: 1. The grinding baffle is closed. 2. The dust collection chambers of each bag are not blowing back properly. 3. Dust bag pasted with coal powder 4. Poor air lock of dividing wheel

　　Solution: 1. Open the grinding baffle. 2. Notify on-site processing. 3. Control the upper limit of the grinding temperature deviation. 4. Notify relevant processing

　　Twelve Reason: The temperature of the bag dust collection hopper is too high

　　Phenomenon: 1. Ash accumulation in the ash hopper 2. Ash hopper catching fire

　　Solution: 1. Notify the site for handling. 2. Stop the machine and extinguish the N2 fire

　　Thirteen Reason: Quantitative coal feeder motor tripped

　　Phenomenon: The feeding amount drops to zero

　　Solution: 1. Equipment other than the coal feeding equipment in the system should continue to operate. 2. Gradually reduce the amount of hot air entering the mill and slowly open the cold air door at the inlet of the coal mill to maintain the gas temperature at the outlet of the coal mill below 70 ℃. 3. During normal shutdown, stop the system according to the operating sequence after the shutdown of the coal feeding system equipment

　　Fourteen Reason: Coal mill motor tripped

　　Phenomenon: The current of the grinder is zero

　　Solution: 1. Due to interlocking between equipment, the coal feeding system equipment will be immediately shut down. 2. Quickly open the cold air door at the coal mill inlet and close the hot air door to maintain the gas temperature at the coal mill outlet below 70 ℃. 3. When the slow rotating device of the coal mill can work, the system should be shut down according to the operating sequence after the normal shutdown of the coal mill. 4. When the slow rotation system of the coal mill cannot work, follow the following steps: fully close the inlet hot air pipeline valve, fully open the inlet cold air valve of the coal mill, and gradually reduce the outlet gas temperature of the coal mill to below 50 ℃. The exhaust fan system and coal powder conveying system equipment have been shut down.

　　Fifteen Reason: Coal mill exhaust fan motor tripped

　　Phenomenon: The main motor of the coal mill, the powder selector, the feeder, and the hot air fan trip, and the current drops to zero

　　Solution: 1. The coal mill and coal feeding system equipment are immediately shut down due to interlocking. 2. Close the hot air valve of the coal mill and open the cold air valve to reduce the inlet temperature of the coal mill. 3. Stop other equipment in the order of normal shutdown of the coal mill exhaust fan

　　Sixteen Reason: Motor trip of coal powder conveying equipment

　　Phenomenon: The main motor of the coal mill, the powder selector, the feeder, and the hot air fan trip, and the current drops to zero

　　Solution: 1. Fully close the inlet baffle of the coal mill exhaust fan and stop the fan. 2. Due to the interlocking relationship between the equipment, the coal mill and coal feeding equipment should be immediately stopped and switched to the auxiliary drive, and operated according to the normal shutdown steps

　　Seventeen Reason: The coal mill suddenly cut off coal

　　Phenomenon: 1. Blockage of coal mill raw coal bin 2. Blockage of grinding chute 3. Blockage of electric flap valve 4. Malfunction of raw coal conveying line

　　Solution: 1. Open the cold air valve at the inlet of the coal mill to keep the outlet gas temperature below 70 ℃

　　2. If the slider is blocked, immediately clean the slider. If the processing time exceeds 20 minutes, stop grinding

　　18 Reason: Coal mill blockage

　　Phenomenon: 1. Decreased grinding sound. 2. Blockage of drying bin. Excessive moisture content in raw coal. 3. Blockage of grinding bin, resulting in excessive coal feeding

　　Solution: 1. Quickly stop coal feeding. 2. Maintain normal air flow. 3. When the outlet gas temperature of the coal mill tends to exceed 80 ℃, reduce the inlet temperature of the coal mill

　　Nineteen Reason: Internal fire in coal mill

　　Phenomenon: 1. The outlet temperature of the coal mill suddenly exceeds 80 ℃. 2. The paint on the grinding cylinder peels off

　　Solution: 1. Quickly identify the ignition point. 2. Stop grinding immediately and close the coal mill inlet valve. 3. Immediately inject N2 gas or water into the mill

　　Twenty Reason: Bag dust collection outlet gas temperature rise alarm

　　Phenomenon: Spontaneous combustion of accumulated coal powder

　　Solution: 1. According to the alarm, increase the opening of the cold air door at the coal mill inlet to lower the temperature. 2. When a fire is confirmed, the system will be shut down urgently, close the inlet and outlet valves of the bag dust collector, and inject N2 into the bag dust collector. 3. Open the gate on site and discharge the coal powder

　　Twenty one Reason: Alarm for coal powder temperature rise in ash hopper

　　Phenomenon: Spontaneous combustion of accumulated coal powder

　　Solution: 1. Emergency shutdown of the system, stop the reverse air blowing system, and close the inlet and outlet valves of the bag dust collection

　　2. Spray N2 to extinguish the fire. 3. Open the gate valve on site and discharge the coal powder

　　22 Reason: The temperature inside the coal powder silo is rapidly rising

　　Phenomenon: Accumulation of coal powder spontaneous combustion

　　Solution: 1. Emergency shutdown of the system. 2. Close the lower gate of the warehouse. 3. When confirming a fire, spray N2 to extinguish it

　　Twenty three Reason: Coal powder leakage in the warehouse

　　Phenomenon: 1. Coal powder silo is fed under positive pressure. 2. Local coal powder explosion causes deformation of flanges and other components

　　Solution: 1. Check if the upper dust collection pipeline is blocked, and use methods such as hammering and listening to sound to identify. 2. Check if the explosion-proof valve on the warehouse is damaged

　　24 Reason: Coal powder silo explosion

　　Phenomenon: Intense combustion in a confined space, resulting in a sharp increase in air pressure

　　Solution: 1. Immediately shut down the coal powder preparation system and close the air lock valve. Report to the leadership, delineate the area, clean up the spilled coal powder, repair the system equipment, organize acceptance, and put it into operation after passing the acceptance

　　Twenty five Reason: Damaged explosion-proof valve disc, air leakage, coal powder overflow, explosion sound

　　Phenomenon: 1. Rapid decrease in negative pressure of the system. 2. Too high temperature of the grinding gas. 3. High temperature or sparks generated by equipment friction and impact

　　Solution: 1. Emergency shutdown of the coal mill system. 2. Confirm the internal fire situation of the equipment. If there is an internal fire, take measures to extinguish it and discharge the ignition coal powder before handling it. 3. Repair the damaged explosion-proof valve, replace the valve disc, and replace the flange if it is damaged. 4. Clean up the overflowing coal powder

　　26 Reason: Scale stuck

　　Phenomenon: Large blocks or bars, angle steel stuck

　　Solution: 1. Remove it. 2. Check for belt damage

　　27 Reason: Sudden change in scale measurement value

　　Phenomenon: There are foreign objects or damage to the weighing device

　　Solution: 1. Remove foreign objects from the scale body. 2. Notify the department for confirmation