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Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Animal or vegetable oils such as linseed oil, cooking oil and cottonseed oil undergo spontaneous combustion when in contact with rags or other combustible materials. The oxidation reaction that occurs with animal or vegetable oils is different than the reaction with hydrocarbon petroleum-based materials. The oxygen from the air trapped in the mass reacts with the double bonds present in the animal or vegetable oils. The braking of the double bonds creates heat, which ignites the materials when they reach their respective ignition temperatures.
Underground mining/stoping methods & mine closure
Published in Ratan Raj Tatiya, Surface and Underground Excavations, 2013
Spontaneous Combustion: Spontaneous combustion is a process whereby a substance can ignite as a result of internal heat which arises spontaneously due to reactions liberating heat faster than it can be lost to the environment. The spontaneous heating of coal is usually slow until the temperature reaches about 70°C, referred to as the “crossover” temperature. Above this temperature, the reaction usually accelerates. At over 300°C, the volatiles, also called “coal gas” or “cracked gas”, are given off. These gases (hydrogen, methane and carbon monoxide) will ignite spontaneously at temperatures of approximately 650°C (it has been reported that the presence of free radicals can result in the appearance of flame in the coal at about 400°C). The processes involved in a classic case of spontaneous combustion are presented in table 16.1(b) (different coals will produce varying pictures).
Effect of feedstock, impurities, and rancidity on likelihood of spontaneous combustion of oil and biodiesel
Published in Biofuels, 2022
Brian Hanson, Dev S. Shrestha, Chad Dunkel
Many fire incidents have been attributed to spontaneous combustion. The National Fire Protection Association (NFPA) defines spontaneous combustion as a byproduct of spontaneous heating, a process by which a material increases in temperature without uptaking heat from its surroundings. If a material reaches its ignition temperature, spontaneous ignition or combustion occurs. An NFPA study showed between 2005 and 2009, 9% of all spontaneous combustion fires were in manufacturing, many of which caused property damage [7]. Literature indicate stored coal, and barns containing hay catching fire with no known form of ignition [8, 9]. Spontaneous combustion causes thousands of fires each year, with a quarter of the fires in manufacturing beginning from oily rags [7]. Spontaneous combustion can happen with any type or brand of absorbent media: mats, wipers, rags, corncob, sawdust, clay, wood chips, or peat [10].
On the Performance Assessment of ANN and Spotted Hyena Optimized ANN to Predict the Spontaneous Combustion Liability of Coal
Published in Combustion Science and Technology, 2022
Abiodun Ismail Lawal, Moshood Onifade, Jibril Abdulsalam, Adeyemi Emman Aladejare, Abisola Risiwat Gbadamosi, Khadija Omar Said
When coal is exposed to the atmosphere, it interacts with oxygen to undergo oxidation, a process that is exothermic in nature (Guo et al. 2019). The process releases noxious gases, water vapor, and heat energy (Jun et al. 2019). When this heat is produced at a faster rate than it is released to the surrounding environment, it builds up in the coal mass to meet its activation energy (Abdulsalam et al. 2020; Banerjee 2000). This results in coal fire, a phenomenon commonly known as spontaneous combustion. This process occurs in both surface and underground mines but it is more catastrophic in underground mines due to the confined space and methane gas buildup (Onifade and Genc 2020; Zhang et al. 2013). Spontaneous combustion is the biggest challenge in coal mining that jeopardizes both safety and economic base of companies involved (Deng et al. 2015; Zhao et al. 2019). Coal fires can result in death of miners caught in such incidents due to extreme burning cases or inhalation of noxious gases (oxides of nitrogen, carbon, and sulfur) produced (Jun et al. 2019). The devastating effects of this phenomenon can destroy mine assets such as mining machinery, equipment, power substations as well as coal deposits that are the main mining resources (Onifade 2018). Most importantly, the noxious gases produced contribute to global warming due to generation of greenhouse gases (Jun et al. 2019; Panigrahi and Ray 2014).
Internal Heat Extraction by Gravity Heat Pipe for Spontaneous Combustion Remediation
Published in Combustion Science and Technology, 2022
Wan-Xing Ren, Xin Liu, Zhen-Guo Sun, Qing Guo
Most of the coal mined in China has a propensity to spontaneously combust, as it does in other coal-mining countries like Poland, Russia, the Czech Republic, Austria, and so on (Fernández-Alaiz et al. 2020; Tutak et al. 2017). The spontaneous combustion of loose coal is a serious problem that affects coal mining, transportation, and storage and thus spontaneous combustion is a significant safety management problem. Since the spontaneous combustion of coal is determined by human and natural factors such as accumulation type, air temperature, and wind speed, the causes of spontaneous combustion are dispersed and difficult to pinpoint, and air leakage and oxygen availability are difficult to monitor. The challenge of stopping and regulating coal spontaneous combustion is compounded by these causes. Spontaneous combustion will occur where there are flammable goods, enough oxygen, and a good thermal storage environment (Deng et al. 2015). From the standpoint of prevention and regulation, the spontaneous combustion of coal piles (gangue piles) may be destroyed if one of these three conditions is removed(Li, Gao, Jun et al. 2020). At present, the primary strategy used to prevent spontaneous combustion is to prevent oxygen from coming into contact with the coal and to reduce oxygen concentration in coal piles. These techniques take a long time to work and require a lot of effort. Another strategy is to extract the internally generated heat from the coal piles, preventing heat accumulation and spontaneous combustion. But there have been few studies on internal heat extraction (Szurgacz et al. 2020; Brodny and Tutak 2018). In the long term, it is an important technical proposal for coal spontaneous combustion prevention and control programs using technical means to extract heat from coal piles.