Investigating the effect of coal particle size on spontaneous combustion and oxidation characteristics of coal

• Published in: Environmental science and pollution research international 2022-03, Vol.29 (11), p.16113-16122
• Main Authors: Jia, Xiaoliang, Wu, Jiaokun, Lian, Changjun, Wang, Jianjun, Rao, Jilai, Feng, Renjun, Chen, Yong
• Format: Article
• Language: English
• Subjects: Activation energy; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Coal; Combustion; Critical temperature; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Functional groups; High temperature; Oxidation; Oxidation process; Oxidation-Reduction; Oxygen; Oxygen consumption; Particle Size; Research Article; Spontaneous Combustion; Temperature; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499; 1614-7499
• DOI: 10.1007/s11356-021-16929-1

As a key parameter, the particle size of residual coal contributes greatly to its oxidation characteristics, so it is a significant and far-reaching topic to explore the role of different particle sizes in coal spontaneous combustion disaster. In this work, temperature-programmed system (TPS) was applied to analyze the oxygen consumption rate and CO and C 2 H 4 production rules of six groups of coal samples with different particle sizes in the process of oxidation heating. The critical temperature (CT) and xerochasy temperature (XT) of different coal samples were obtained, and the coal oxidation process was divided into three stages (S1, slow oxidation stage; S2, fast oxidation stage; and S3, combustion stage). Then, the apparent activation energy ( E ) and pre-exponential factor ( A ) in three stages were regressed combined with Arrhenius formula. The results show that the smaller the coal particle size is, the larger the specific surface area is, the stronger the adsorption capacity of coal molecules and oxygen molecules is, resulting in the larger oxygen consumption rate. The values of CT and XT with particle size of 0.125–0.18 mm and 2–4 mm are the smallest and largest. For coal samples with the same particle size, the maximum values of E and A occur in stage S3 and the minimum values appear in stage S1. This is mainly due to the higher temperature of stage S3, which allows the activation of functional groups with higher apparent activation energy, stronger collisions between activated molecules, and more intense oxidation reactions.