Application of the curved coal chute at Hongliu Coal Preparation Plant

The problems encountered with the use of the original linear chute for transfer of coarse coal involve high percent of size reduction of coarse coal, proneness to blockage, severe wear of inner wall, and difficulty in replacement of chute. To address these issues, following an analysis of the raw coal property, test is made on the transfer of the coarse coal product of the plant′s 218^# flip-flop screen with an independently developed curved chute in place of the linear chute. Then the figures of size reduction of coarse coal passing through the chute before and after the use of the curved chute are compared through screen analysis. Practice shows that the curved chute is unapt to get clogged up, and both impact force and downslide resisting force are reduced; the bumping force of the coal and the friction between the coal and the surface of the chute produced by downfall of coal are both decreased, resulting in therefore less reduction of size of coal; and at the discharge end of the chute, the breakage rate of the >50 mm coal drops by 1.14 percentage points on average, down by 0.39 percentage point compared with the figure before the use of the curved chute, creating an additional economic gains of around 1.868 million yuan for the plant per year. Shifting to the use of the curved chute has led to not only less breakage rate of coarse coal, but also higher coal transfer efficiency, improved performance of heavy-medium separation system, and noticeably reduced operating and maintenance costs.