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Ionic liquids( ILs) is a new type inhibitor, which can dissolve and destroy the active functional structures in coal to inhibit coal oxidation process and achieve the inhibitor effect of coal spontaneous combustion.To investigate the effect of imidazolium-based ILs on the weigh loss and heat transfer of coal, 1/3 coking coal of Dingji in Huainan Mining Area was collected as experimental coal, which was treated by ILs for[EMIM][BF4], [BMIM][BF4], [BMIM][NO3], and[BMIM][I], with IL-untreated( IL-untc) coal acting as the control group, synchronous thermal analyzer( TG-DSC) and Laser pyrometer experiment were employed to obtain weight loss and thermophysical parameters of imidazolium-based ionic liquids treatment coal.The results showed that ILs on coal spontaneous combustion process had a significantly reduced mass loss, the best effect was[BMIM][BF4].Moreover, the results of differential thermal analysis showed that the heat release of ILs-treated coal samples were lower than IL-untc coal, of which the peak temperature of the[BMIM][BF4]treated coal sample increased 28 C°.Thermophysical parameters for all coal samples presented a phased variation.With the elevation of temperature between 30 to 210 C°, thermal diffusivity gradually decreased, specific heat capacity and thermal conductivity increased.However, when the temperature was beyond 210 C°, thermal diffusivity increased, the increasing tendency of specific heat capacity was weak and thermal conductivity rapidly increased.In a same temperature, the thermal diffusivity and thermal conductivity of IL-treated coal were lower than that of raw coal, and the specific heat capacity is higher than that of raw coal.The smallest thermal diffusivity and thermal conductivity, and the biggest specific heat capacity were found for[BMIM][BF4]treated coal.Furthermore, the sensitivity of[BMIM][BF4]treated coal on temperature obviously weakened, which indicated that the inhabiting effect of[BMIM][BF4]on heat transfer was stronger.These results provide a theoretical basis and realistic guidance for the prevention of coal fire. [ABSTRACT FROM AUTHOR]

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Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ionic liquid(IL) is a new type inhibitor, which can inhibit the active functional groups in the molecular structure in coal, and inhibit coal oxidation process. However, different metamorphic coal samples have different microstructures. Moreover, IL has high cost, which is difficult to implement in the field of coal spontaneous combus-tion(CSC). To investigate the effects of IL on the thermal properties of CSC with different metamorphic levels, consid-eringeconomics and practicality, low concentration(5 mass%) 1-butyl-3-methylazole tetrafluoroborate([BMIM][BF4])is used to treat coal samples. Using simultaneous thermal analysis(STA) and laser flash apparatus(LFA), the oxidation and exothermic behaviors of four types of coal were analyzed. The characteristic temperature, thermal effects and thermophysical parameters of coal with different metamorphic levels of IL treatment were obtained. The results show that the [BMIM][BF4]delayed the characteristic temperature of coal mass loss, increased the initial/maximum heat release temperature, and reduced the maximum heat release rate/thermal release during CSC. Moreover, the inhibition effect decreases as the levels of coal metamorphism increases. Compared with the raw coal sample, the thermal diffusion coefficient and thermal conductivity of the treated coal sample are lower, and the specific heat capacity is higher. Namely, the [BMIM][BF4]reduces the rate of heat transfer between coal bodies and weakens the ability to transfer heat due to temperature difference, increases the heat required to raise the temperature of the coal bodies. In addition, the lower the levels of coal metamorphism, the more significant the inhibiting impact on CSC. The study results provide a theoretical basis for the promotion and application of IL inhibit at CSC field. [ABSTRACT FROM AUTHOR]