Coal Grinding Mill

Coal Grinding Mill

Our company's 2000t/d production line uses Φ2.8m×8m ball mill, which has high power consumption and poor drying effect. The dust collection equipment is an electrostatic precipitator. Due to the aging of equipment, the dust content in the exhaust gas is easy to produce when the production fluctuates. Exceeding the standard phenomenon, affecting the surrounding environment. Therefore, it was decided to carry out technical transformation of the coal grinding system, and a new ZGM113K vertical mill was built next to the original grinding mill instead of the ball mill, and the frame structure and storage bin of the original mill system were fully utilized to save the project investment, and the electrostatic precipitator was changed to bag dust removal.

Optimize the design plan of Coal Grinding Mill

1. Adjust the angle of the raw coal conveying belt

In the initial design, the original coal conveying belt angle was 17°. According to the actual use in production, the angle of the winter belt conveyor was too large, causing the raw coal to slip on the belt. Therefore, by adjusting the site layout, the height of the head was reduced by 2m. , so that the angle of the conveyor belt is <15°. After the coal vertical mill was put into operation, there was no belt conveyor slippage in the winter, which ensured the continuity of production.

2, change the way of feeding locks

In order to reserve space for the adjustment of the angle of the conveyor belt conveyor, the coal feeder above the Coal Grinding Mill in the original design was cancelled, and the high-precision rotary feeder + electric double flap lock damper was used to directly feed the raw coal into the stand. Grinding reduces the gap between the belt conveyor and the vertical mill. The wind lock effect is good after running.

3. Increase the storage capacity of tail coal bins

When designing a pulverized coal bin in a general design institute, the storage capacity of the two pulverized coal bins of the head and tail coal is the same. The storage capacity of the head and tail coal powder warehouses used by our company are both 45t, but in actual production, the coal consumption of the head and tail coal is about 4:6. When the position is low, it is easy to see that the coal under the tail coal is unstable, which affects the stability of the kiln system, resulting in a short stop time of the Coal Grinding Mill, frequent opening and stopping, and increased power consumption.

At the time of design, we changed to a larger storage capacity of No. 3 pulverized coal bin (storage capacity 70t) as a tail coal bunker, which can extend the continuous running time of the Coal Grinding Mill. Ensure that the coal in the head and tail coal powder bins is balanced, the grinding time of the Coal Grinding Mill is extended from 2h to 3.5h, and the grinding and stopping grinding is reduced by 2~3 times every day, and the peak avoidance electricity can be arranged reasonably, and the power consumption is reduced.

4, into the hot air duct to increase the cold air valve

When designing the hot air duct of Coal Grinding Mill, in addition to a cold air valve to adjust the air temperature of the bag filter before the hot air is collected, a cold air valve is added to the outlet pipe of the hot air fan, which has two functions: 1) due to the distance from the Coal Grinding Mill inlet is relatively close, which can achieve rapid cooling when stopping grinding, shorten the cooling and stopping time, reduce the un-dried coal powder into the kiln system; 2) adjust the hot air temperature, compared with the cold air valve before dust collection, it It can effectively reduce the resistance of the hot air dust collection system and the power consumption of the hot air blower.

5, using a chain conveyor instead of a screw conveyor to transport back to the ash

The hot air dust collection and returning ash system adopts the FU type chain conveyor in design. Compared with the screw conveyor: 1. The failure rate is low, the maintenance is small, and a stable material flow can be formed at a certain material layer height, and the operation is stable. Good , generally no pressure stop accident. 2, the transmission energy consumption is low, by means of the internal friction of the material, the material is pushed to pull the animal material, the running resistance is small, and the power saving is 40% to 60% compared with the screw conveyor. Our company's current gray zipper machine takes 20min and stops for 2h, and it can automatically start and stop through program control, reducing power consumption.

6, the wear pipe is made of wear-resistant ceramic lining

The pipe at the exit of the Coal Grinding Mill is increased due to the sudden decrease of the pipe diameter, resulting in serious wear and tear, which often causes leakage of the system. In the transformation, the outlet pipe is lined with wear-resistant ceramic sheets, which greatly prolongs its service life.