Authors: V.A. Portola, S.A. Yarosh, A.A. Bobrovnikova, A.A. Portola

Title of the article: The usage of spontaneous combustion of coal to produce thermal energy

Year: 2023, Issue: 5, Pages: 92-103

Branch of knowledge: 2.8.6. Geomechanics, destruction of rocks by explosion, mine aerogasdynamics and mining thermophysics

Index UDK: 622.822

DOI: 10.26730/1999-4125-2023-5-92-103

Abstract: Accumulations of coal and carbon-containing rocks in contact with air are oxidized, which can lead to spontaneous combustion. Observations show that the sizes of heat anomalies arising from endogenous fires in rock dumps reach hundreds and thousands of meters, and the depth of warming reaches 10 m and more. The supply of refrigerant to extinguish such spontaneous combustion leads to the transfer of heat to the underlying rock layers and their warming up. The calculation showed that the place of spontaneous combustion with a size of 1 m in depth and a temperature of 200 °C after the water supply will additionally warm up the rock layer with a thickness of 1.3 m to 70 °C, and the total depth of warming will already be 2.3 m. After the refrigerant supply is stopped and the air supply is restored, the fire of a larger size can reoccur. To increase the efficiency of extinguishing spontaneous combustion, it is advisable to use refrigerant recirculation. The delivery of heated refrigerant to the surface will not only prevent an increase of heat anomalies in volume, but will also allow using heat from fires for economic purposes. The proposed schemes provide for drilling into the places of spontaneous combustion and installation of pipes through which the refrigerant shall circulate. In the place of combustion, the refrigerant evaporates and the steam rises into the heat exchanger, where it gives up heat, condenses and flows again down the inner surface of the pipe to the place of combustion. A direct-flow scheme requiring a pump to supply liquid refrigerant to the place of combustion is also considered.

Key words: spontaneous combustion endogenous fire coal temperature heat content fire extinguishing refrigerant rock dump use of fire source heat

Receiving date: 25.09.2023

Approval date: 20.11.2023

Publication date: 30.11.2023

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