Innovative Application of Roller Disc Screening Technology at Zhao Gu Yi Coal Preparation Plant (2)

4. Working Principle of the New Roller Disc Screen

The new roller discscreen consists of multiple sets of rotating screens, each screen shaft is equipped with several screen pieces, and the screen pieces on adjacent screen shafts intersect to form screen holes. Materials smaller than the screen holes pass through the screens during operation, while block-shaped materials larger than the screen holes roll on the screen pieces and are discharged from the outlet. The screening principle is shown in Figure 1. The newroller disc screen has a screening mechanism of "dynamic screen holes, self-cleaning of materials," with the advantages of high screening efficiency, high reliability, high environmental protection, and large single-machine processing capacity.

In traditional grading equipment, such as vibrating screen equipment (loose screen, high-amplitude screen, banana screen), rolling screen, compound sinusoidal screen, etc., due to the screening mechanism and structure, there are common problems of low screening efficiency and high failure rate in grading fine powdered coal. The new roller disc screen overturns the traditional screening concept, applicable to screening any type of coal, especially coal with high water content, high viscosity, and severe mud, with a high mud removal efficiency. It will become a new generation of efficient screening machine to replace traditional screening equipment.

5. On-Site Application Analysis of the Roller Disc Screen

5.1 Application Situation

Zhao Gu Yi Mine coal preparation plant uses a new roller disc screen with a length of 8.4 m and a width of 2.2 m to grade and screen raw coal. The screen discs are arranged in a mutually intersecting manner, with the first section using a 8 mm grade and the second section using a 13 mm grade. After the application of the new roller disc screen, Zhao Gu Yi Mine achieved direct production of screened fine coal products, solving the problem of the original design where raw coal could only be wet screened, and after the screened material was completely de-mudded through a three-product cyclone sorter, washed fine coal, medium coal, and gangue were mixed again to enter the fine coal bin. It reduces the amount of coal slurry and makes the production system more complete and flexible to meet market demand. The comparison of product yields before and after the application of the new roller disc screen is shown in Table 2.

From Table 2, it can be seen that the coal slurry yield after the application of the roller disc screen is 17.23%, a decrease of 1.48% compared to before the application; the fine coal yield is 19.90%, an increase of 1.92% compared to before the application; and the gangue yield is 14.71%, a decrease of 0.44% compared to before the application.

5.2 Economic Benefits Analysis

As shown in Table 3, the coal preparation plant at Zhao Gu Yi Mine had an incoming washed raw coal volume of 1.7711 million tons from May to September, reducing the coal slurry volume by 26,200 tons. The operating income before coal slurry reduction was 977.5909 million yuan, and the operating income after coal slurry reduction was 984.7140 million yuan, resulting in an increased income of 7.1231 million yuan.

Conclusion

The application of the new roller disc screen at Zhao Gu Yi Mine coal preparation plant shows that the equipment has high screening efficiency, especially for coal types with high water content, high viscosity, and severe mud. After the application at Zhao Gu Yi Mine coal preparation plant, it not only improves the washing process, reduces the coal slurry yield, and alleviates environmental pressure but also increases the economic benefits of the coal preparation plant.