Prediction Of Spontaneous Combustion Research Articles

Spontaneous Combustion Prediction of Coal by C80 and ARC Techniques

Many coal fires were caused by spontaneous combustion in coal mines or coal storehouses, which resulted in a great loss and energy wastage. To identify and evaluate the hazardous degree of coal stockpile, a C80 microcalorimeter and accelerating rate calorimeter (ARC) were employed in this work. The coal samples undergo an exothermal process start at 80 °C with heat generation of −75.1 J g−1(mean value) detected by C80 experiment. The activation energies of the first exothermal process were calculated for the three experiments, and the mean value is 80.76 kJ mol−1, which is lower than that of obtained from the ARC result, 127.0 kJ mol−1. For a 300 tons coal stockpile, the self-heating oxidation temperatures (SHOT) were calculated as 164, 60, 90, and 68 °C based on the ARC experiment and three C80 experiments, respectively. Further research on the mass effect on SHOT shows that if the coal mass is less than 12 tons, the danger of thermal spontaneous combustion is less. However, if the mass amount is more th...

Internet-based monitoring and prediction system of coal stockpile behaviors under atmospheric conditions

Spontaneous combustion on industrial-scale stockpiles causes environmental problems and economic losses for the companies consuming large amounts of coal. In this study, an effective monitoring and prediction system based on internet was developed and implemented to prevent losses and environmental problems. The system was performed in a coal stockpile with 5 m width, 10 m length, 3 m height, and having 120 t of weight. The inner temperature data of the stockpile was recorded by 17 temperature sensors placed inside the stockpile at certain points. Additionally, the data relating to the air temperature, air humidity, atmospheric pressure, wind velocity, and wind direction that are the parameters affecting the coal stockpile were also recorded. The recorded values were analyzed with artificial neural network and Statistical modeling methods for prediction of spontaneous combustion. Real-time measurement values and model outputs were published with a web page on internet. The internet-based system can also provide real-time monitoring (combustion alarms, system status) and tele-controlling (Parameter adjusting, system control) through internet exclusively with a standard web browser without the need of any additional software.

A NEW DIMENSION TO STUDIES OF SPONTANEOUS COMBUSTION OF COAL

Spontaneous combustion of coal is a hazard frequently encountered in coal mining. It has been researched extensively but the actual mechanism by which it occurs is not completely understood. Under suitable conditions, the spontaneous combustion hazard manifests itself in all major aspects of coal mining, namely, underground coal mining, surface mining, stockpiling of coal at the pithead, power stations and ports, during sea-borne transport and stacking of reject material. In underground coal mining, the most difficult situation occurs when spontaneous combustion takes place in the presence of an inherently explosive atmosphere which may promote a local spontaneous combustion incident into an explosion hazard involving the entire mine. Such an incident at the Moura mine in Central Queensland resulted in greater pressure on mine operators for the safe management of spontaneous combustion in their underground coal mines than ever before. As not all coal mines are equally liable to spontaneous combustion due to the different propensities of different coals to self-oxidation, the risk assessment for spontaneous combustion is a primary requirement for the development of a spontaneous combustion management plan for a mine. Once the coal seam has been classified into various categories of spontaneous combustion risk, it is necessary to determine a fire ladder for the coal seam. This should be followed by detailed planning of the mine layout including the mine ventilation system and a spontaneous combustion monitoring program before devising a spontaneous combustion management plan as required by the Coal Mines Underground Regulations 1999. In this paper, a case history is presented which includes the development of a spontaneous combustion management plan for a high-risk coal seam in a greenfield site, from the risk assessment stage to the outbreak stage of a spontaneous combustion incident. It is concluded that the risk assessment, evaluation of the fire ladder, comprehensive monitoring by a tube bundle system and trending of carbon monoxide/oxygen deficiency ratio (Graham's ratio) and CO levels were the main elements in an effective spontaneous combustion control system for the mine.

Characteristics of gases produced in process of coal oxidation and their relations with selection of gas markers for prediction of spontaneous combustion (in Chinese) : He Ping, Wang Feiyu & Tang Xiuyi, Journal - China Coal Society, 19(6), 1994, pp 635–643

Characteristics of gases produced in process of coal oxidation and their relations with selection of gas markers for prediction of spontaneous combustion (in Chinese) : He Ping, Wang Feiyu & Tang Xiuyi, Journal - China Coal Society, 19(6), 1994, pp 635–643