咪唑类离子液体处理煤热失重以及传热特性研究

离子液体作为新型阻化剂，溶解破坏煤中的活性结构从而抑制煤氧化反应进程，达到阻化煤自燃的效果。为了考察咪唑类离子液体对煤热失重以及热传递特性的影响，采集淮南矿区丁集1/3焦煤作为实验煤样，选取[EMIM][BF4]，[BMIM][BF4]，[BMIM][NO3]和[BMIM][I]对焦煤处理，并将未处理煤样作为对照组，开展热重-差热同步热分析实验和激光导热实验，得出咪唑类离子液体处理煤的热失重和热物性参数。结果表明:离子液体对煤的氧化热失重过程有明显的减弱作用，且不同离子液体的作用效果不同，效果最好的为[BMIM][BF4]。此外，差热结果显示离子液体处理煤的放热量均低于离子液体未处理煤，其中[BMIM][BF4]处理煤相比较于原煤，波峰温度提高28 ℃。煤样的热物性参数呈现出阶段性变化。30~210 ℃，随着温度的增加，煤样的热扩散系数逐渐降低，比热容和导热系数逐渐增大;210 ℃之后，煤样的热扩散系数逐渐上升，比热容趋于平稳，导热系数快速上升。在同一温度下，离子液体处理煤的热扩散系数以及导热系数均低于原煤，离子液体处理煤的比热容均高于原煤，其中[BMIM][BF4]处理煤的热扩散系数最小，比热容最大，导热系数最小。此外，[BMIM][BF4]处理煤热物性参数变化率最低，对温度的敏感性明显减弱，对煤热量传递抑制作用明显。结果可为煤火的防治提供一定的理论基础和现实依据。

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 Mining Area was collected as experimental coal,which was treated by ILs for[EMIM][BF4],[BMIM][BF4],[BMIM][NO3],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][BF4].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][BF4]treated coal sample increased 28 ℃.Thermophysical parameters for all coal samples presented a phased variation.With the elevation of temperature between 30 to 210 ℃,thermal diffusivity gradually decreased,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 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][BF4]treated coal.Furthermore,the sensitivity of[BMIM][BF4]treated coal on temperature obviously weakened,which indicated that the inhabiting effect of[BMIM][BF4]on heat transfer was stronger.These results provide a theoretical basis and realistic guidance for the prevention of coal fire.