Self-ignition risk classification for coal dust layers of three coal types on a hot surface. (1st February 2021)

• Record Type: Journal Article
• Authors: Li, Bei; Liu, Gang; Bi, Ming-Shu; Li, Zhen-Bao; Han, Bing; Shu, Chi-Min
• Is Part Of: Energy. Volume 216(2021)
• Publication Date: 2021-02-01
• Subjects: Pulverised coal -- Spontaneous combustion -- Dust explosion -- Thermal runaway -- Thermodynamic parameters; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2020.119197
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: Pulverised coal in industrial sites and their dust can experience spontaneous combustion and self-heating, increasing the risk of fire and dust explosion. The main objective of the present study was to resolve thermal combustibility (as reflected by comprehensive combustibility index [ S n ] and kinetic properties) for three types of coal (S1-BN, S2-CY, and S3-JM) through thermal analysis. The S n values of the samples indicated a degradation in the quality of comprehensive combustibility. Apparent activation energies ( E a ) at the initial stage of spontaneous coal combustion (130–300 °C) were decided through Achar and Coats–Redfern methods. Moreover, thermal susceptibility (minimum auto-ignition temperature [MAIT] and thermodynamic parameters) was evaluated using the hot plate method. The MAIT values for the three coal dust layers were 210, 220, and 300 °C. The results exhibited that heat conduction was the dominant heat transfer mode that originated the temperature distribution within the coal dust layer under the subcritical conditions for ignition; while it converted chemical reaction controlled-mode after thermal runaway. Furthermore, the results based on an improved risk matrix approach showed the S1-BN and S2-CY samples had a high self-ignition risk, whereas the S3-JM sample had a moderate ignition risk. H I G H L I G H T S: Thermal combustibility and susceptibility for coal dust were investigated. Chemical reaction mode regulated the temperature after thermal runaway. Thermokinetic parameters were measured and calculated by TGA and hot surface test. Self-ignition risk of samples was determined using modified risk matrix method.