Research on Comprehensive Dust Control Technology for Belt Conveyors in Coal Preparation Plants

Dust is one of the major occupational hazard factors in coal mine production, and many production processes and operations generate large amounts of dust. When airborne dust enters the human body, it can cause occupational respiratory diseases. During coal transportation, the coal is mainly transferred via multiple belt conveyors to the final sales terminal. The transportation and transfer processes generate significant dust, which not only severely affects the working environment and the health of operators, but also poses an explosion risk,once dust concentrations exceed limits, mine production safety is jeopardized. Based on the dust problems encountered during the operation of belt conveyors at a coal preparation plant in its initial construction phase, we analyze the dust generation mechanisms in order to derive the optimal measures for dust suppression.

1. Analysis of Dust Generation Mechanisms of Belt Conveyors

During coal transportation, the main causes of dust generation by belt conveyors are: relative motion between coal and the conveyor belt, idlers, and chutes, which generates positive/negative pressure airflow and induced airflow, raising dust into the air. The main dust generation points are located at transfer receiving points, along the conveyor line at bend pulleys, idlers, and other areas.

1.1 Dust Generation Mechanism Along the Conveyor Line

The installation quality of a belt conveyor directly affects its safe and reliable operation. Relevant national standards specify clear requirements for the installation accuracy of the conveyor frame, pulleys, straightness, storage belt sections, belt splices, etc. Any non-compliance in these installation parameters may cause local vibration, belt misalignment, and other issues. These problems cause relative movement and friction among the material particles; coal dust particles adhering to the surface of coal lumps undergo relative motion with the coal flow under the action of friction, and under the induced airflow generated by the moving belt, the dust spreads around the equipment with the airflow. Due to the production process and the inherent properties of the material, most of the conveyed material retains a certain moisture content, and during production, spray dust suppression and cooling water from some equipment enter the coal flow, causing some material to adhere to the conveyor belt. During equipment operation, relative motion occurs between the belt and the idlers, pulleys, etc. Under the influence of friction between the material and the idlers and the induced airflow, the adhered coal on the belt surface also generates dust that disperses into the air, polluting the environment.

Based on the above dust generation analysis, the following measures can be adopted:

(1) Adopt comprehensive dust control measures, including enclosed transfer points supplemented by local spray systems, and additional cleaning devices on the return section. Meanwhile, optimizing the conveyor operating speed and improving installation accuracy can effectively control dust and improve the environment. This approach also offers the lowest investment and operating costs.

(2) Scientifically and rationally design the dimensions and angle of the enclosed chute at transfer points to suppress dust generation.

(3) Install high-efficiency cleaning devices on the return section of the belt conveyor and control the moisture content of the coal material to effectively reduce dust generation in the return section.

(4) Control the installation accuracy of the frame, pulleys, idlers, and other equipment along the conveyor line to ensure stable and reliable operation, which can effectively reduce dust generation.

(5) Relying solely on conventional single dust suppression measures, such as dynamic dust collection or spray dust suppression, cannot achieve comprehensive dust control; they are only suitable for local environmental improvement and are often accompanied by high operating costs, secondary pollution, and other issues. Such single-measure approaches are not conducive to the standardization and intelligent development of coal preparation plants. Therefore, the plant should adopt a combined multi-method dust control strategy.