Coal Dust Severity in a Power Plant: In-Situ, Analytical, and Numerical Assessments

Abstract

One of the most serious occupational hazards in the coal industry is coal dust. Previous research revealed that the vast majority of coal dust assessments were conducted in coal mines, resulting in a lack of understanding of the severity of coal dust during coal handling activities in power plants. Therefore, the severity of combustible coal dust in one of Malaysia's power plants was assessed using a comprehensive analysis that included qualitative observations, in-situ measurements, numerical simulations, laboratory tests, and data analysis. The designated locations include the coal conveyor hall (Zone 1, 2A, and 2B), milling (Zone 3), and bunkering areas (Zone 4). Relevant safety limits, as recommended in National Fire Protection Association (NFPA) 654, were used as guidelines where comparisons with the site data were made. The high coal dust accumulation rate in Zone 1 was revealed to be largely the result of inefficient ventilation performance, as confirmed by in-situ measurement and numerical simulation. Direct referencing to the relevant NFPA 654 guidelines finds the zones encompassing the coal conveyor hall are at “high risk” of fire and explosion. Further laboratory assessments on the dust samples in Zone 1 however reduces the earlier assessment to “medium risk” with the potential of “low risk” with regular housekeeping. Zones 3 and 4 were found to be “low risk” areas due to insignificant accumulation and good air flow management. Overall, the evaluation of the severity of combustible coal dust was successful in establishing the risk mapping for all zones. Cleaning frequencies were also proposed based on the coal dust accumulation rates and the risk mapping.