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Solution to the collapse problem of the air duct caused by raw material vertical grinding

Date:2019-10-22 13:21     writer:cement editor     Views:

The raw material grinding mill of 7200t/d production line of a certain company adopts two vertical mills, model jlm7-46.4, and the output is 320t/h when designing the mill, and the output is increased to 360t/h when optimizing the process parameters.Due to the small inclination of the vertical mill outlet pipe, the design Angle is 30°. During normal operation, the outlet pipe frequently accumulates materials, and after enrichment to a certain degree, the collapse occurs. In serious cases, the vertical mill directly stops vibrating, which has a great impact on the equipment.Moreover, starting up after shutdown will increase the power consumption of grinding machine, which has a great influence on the production quality.In order to ensure the normal operation of the equipment, the solution of the collapse problem of the raw material vertical mill air pipe is determined to improve the reliability of the equipment.

raw material vertical mill

1. Windpipe collapse reconstruction plan of fresh material vertical grinding

In the raw material A vertical mill and B vertical mill air outlet pipe, add an air charging box, remove the bottom equipment of the 2 vertical mill air outlet pipe and add 4 sets of ceramic air charging box with A width of 480mm (2 sets for each grinding system), wear resistant bolts and flanges, and add A chiller fan of 6110Pa, 2840r/min, 5.5kw and 1257m cubed /h for each of the 2 vertical mill air outlet pipe.

Specific plan:

vertical mill

Two rows of 9.5m long open chute shall be installed in the pipe, with the width of each row of chute 480mm, the spacing of the two rows of chute 180mm, and the chute 300mm away from the bottom pipe.To avoid the chute wear faster, add a perforated plate at the top of the chute to reduce the impact of materials and wind on the canvas.The installation position of the fan is the cement platform below the cyclone cylinder of the vertical grinding wind pipe, and the diameter of the wind pipe is 150mm.

Through the final transformation, the problem of vibration shutdown of the mill caused by collapse of the export pipeline is completely solved, the reliability of the equipment operation is improved, the labor intensity of the post is reduced, the cost of shutdown caused by collapse is reduced, and the cost is saved.


2. Process operation control after modification

raw material vertical mill

Due to the high storage position of homogenized raw materials, a mill is arranged to run under normal conditions to avoid peak during the day. After shutdown, the hot air baffle into the vertical mill is generally closed to avoid air leakage in the system.Due to the large feeding amount of the kiln system, it is easy to accumulate materials in the pipeline after the hot air baffle is closed. In the process of opening grinding, the accumulated materials are easy to collapse from the hot air baffle and enter the human slag discharge pit through the raw material mill.

Before starting grinding, start the vertical mill slag discharge system and force the circulation fan to draw air. At first, the speed of the concentrator should be set at a low 15Hz. Gradually open the hot air baffle at a rate of 3% each time and at an interval of 1min(gradually open to 99%, the process should be slow).Avoid the occurrence of caving when the hot air baffle is closed.

To reform the mill, the wind pipe inner and process control slurry vertical mill by vibration fault eliminate stopped, collapse of the effect of reduced due to the collapse of material on the equipment, reducing the key the increased cost of electricity, reduce the labor intensity of the jobs, let the enterprise realize the authors from the real efficiency, guarantee the safe and stable operation of the system.

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