Characteristic of weight loss and heat transfer for the imidazolium- based ionic liquids treatment coal

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 Min- ing Area was collected as experimental coal,which was treated by ILs forEMIMBF4 , BMIM BF4 , BMIMNO3 ,andBMIMI,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 im- idazolium-based ionic liquids treatment coal. The results showed that ILs on coal spontaneous combustion process had a significantly reduced mass loss,the best effect wasBMIMBF4 . Moreover,the results of differential thermal anal- ysis showed that the heat release of ILs-treated coal samples were lower than IL-untc coal,of which the peak tempera- ture of theBMIMBF4 treated coal sample increased 28 ℃ . Thermophysical parameters for all coal samples presen- ted a phased variation. With the elevation of temperature between 30 to 210 ℃ , thermal diffusivity gradually de- creased, specific heat capacity and thermal conductivity increased. However, when the temperature was beyond 210 ℃ ,thermal diffusivity increased,the increasing tendency of specific heat capacity was weak and thermal conduc- tivity 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 diffusiv- ity and thermal conductivity,and the biggest specific heat capacity were found forBMIMBF4 treated coal. Further- more,the sensitivity ofBMIMBF4 treated coal on temperature obviously weakened,which indicated that the inhab- iting effect ofBMIMBF4 on heat transfer was stronger. These results provide a theoretical basis and realistic guid- ance for the prevention of coal fire.