TY - JOUR
T1 - Experimental study of moisture effects on spontaneous combustion of Baiyinhua lignite from individual particles to stockpile
AU - Zhang, Hemeng
AU - Wang, Yongjun
AU - Zhang, Xiaoming
AU - Sasaki, Kyuro
AU - Sugai, Yuichi
AU - Han, Fangwei
AU - Dong, Wei
AU - Vo Thanh, Hung
N1 - Funding Information:
This work was supported by the Japan Society for the Promotion of Science [ JP-20H02684 , JP-20K21163 ], Scientific research project of Education Department of Liaoning Province [ LJ2020JCL008 ], and Research Grant of Key Laboratory of Mine Thermodynamic Disasters and Control, Ministry of Education, Liaoning Technical University [ JSK202104 ].
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2023/2/15
Y1 - 2023/2/15
N2 - Evaporation and condensation of moisture affect dramatically the spontaneous combustion of lignite with high moisture content at low temperatures. Moisture migration between the lignite and the external environment of coal stockpile encompasses the scales of individual particles and stockpile. The cyclic moisture evaporation/condensation test was applied to investigate moisture migration of individual lignite particles at different particle sizes and temperatures. The wire-mesh basket test was selected primarily to analyze the heating process and critical self-ignition temperature of lignite stockpile. Results of the cyclic moisture evaporation/condensation test reveal that the moisture content of re-saturated lignite is much lower than that of the original one. Moisture content versus time showed a tendency to overlap in repeated moisture evaporation processes, and so did the repeated moisture evaporation processes. Therefore, a model of moisture migration of individual particles was built to describe the repeated moisture evaporation and condensation processes. The time factor determines the speed of moisture evaporation and condensation of individual lignite particles, being inversely proportional to ambient temperature and proportional to particle size, respectively. In the wire-mesh basket test, the heating process of the lignite stockpile can be divided into four stages, but the influence of moisture was more pronounced in stage II. Critical self-ignition temperature is proportional to particle size and increases linearly with moisture content. According to Frank-Kamenetskii theory, an increase in either particle size or moisture content can restrain the tendency of spontaneous combustion of Baiyinhua lignite stockpile.
AB - Evaporation and condensation of moisture affect dramatically the spontaneous combustion of lignite with high moisture content at low temperatures. Moisture migration between the lignite and the external environment of coal stockpile encompasses the scales of individual particles and stockpile. The cyclic moisture evaporation/condensation test was applied to investigate moisture migration of individual lignite particles at different particle sizes and temperatures. The wire-mesh basket test was selected primarily to analyze the heating process and critical self-ignition temperature of lignite stockpile. Results of the cyclic moisture evaporation/condensation test reveal that the moisture content of re-saturated lignite is much lower than that of the original one. Moisture content versus time showed a tendency to overlap in repeated moisture evaporation processes, and so did the repeated moisture evaporation processes. Therefore, a model of moisture migration of individual particles was built to describe the repeated moisture evaporation and condensation processes. The time factor determines the speed of moisture evaporation and condensation of individual lignite particles, being inversely proportional to ambient temperature and proportional to particle size, respectively. In the wire-mesh basket test, the heating process of the lignite stockpile can be divided into four stages, but the influence of moisture was more pronounced in stage II. Critical self-ignition temperature is proportional to particle size and increases linearly with moisture content. According to Frank-Kamenetskii theory, an increase in either particle size or moisture content can restrain the tendency of spontaneous combustion of Baiyinhua lignite stockpile.
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U2 - 10.1016/j.fuel.2022.126774
DO - 10.1016/j.fuel.2022.126774
M3 - Article
AN - SCOPUS:85142888436
VL - 334
JO - Fuel
JF - Fuel
SN - 0016-2361
M1 - 126774
ER -