咪唑类离子液体对煤热物性参数影响的实验研究

Experimental study on influence of imidazolium-based ionic liquids on thermo-physical parameters of coal

离子液体对煤分子结构活性官能团具有显著的溶解破坏作用,从而可以抑制煤热量传递。为了考察咪唑类离子液体([EMIM][BF4]、[BMIM][BF4]、[BMIM][NO3]和[BMIM][I])对煤热物性参数的影响,使用离子液体对不粘煤进行预处理,通过激光闪射装置LFA 457测定在30~300℃范围内煤样的热物性参数,研究离子液体对煤热物性参数的影响,并分析离子液体预处理煤对温度的敏感性。结果表明:随着温度的升高,煤样的热扩散系数逐渐减小,比热容和导热系数逐渐增大,且温度越高,煤样的热物性参数的变化趋势越弱。在相同温度下,离子液体预处理煤的热扩散系数、比热容及导热系数均低于原煤样。在([BMIM]+)相同的情况下,[BF4]-对煤的热扩散系数抑制效果明显;在([BF4]-)相同情况下,[BMIM]+对热扩散系数的抑制效果明显。从敏感性分析可知,煤样的比热容对温度的敏感性最高,导热系数对温度的敏感性最低。此外,在相同温度下,[BMIM][I]处理煤的比热容和导热系数相对较低。实验结果为离子液体抑制煤自燃以及煤火的传热提供理论依据。

Ionic liquids（ILs）has a significant dissolution and destruction effect on the active functional groups of coal molecular structure,thereby achieving the purpose of inhibiting heat transfer in coal.To investigate the effect of imidazolium-based ILs（[EMIM] [BF4],[BMIM][BF4] , [BMIM][NO 3 ], and [I]）on the thermo-physical parameters of coal,the ILs were used to pretreat the non-caking coal,and the laser flash apparatus LFA457 was employed to measure the thermo-physical parameters of coal samples within the range of 30 to 300℃,which investigated the influence of ILs on thermo-physical parameters and analyzed the sensitivity of ILs-treated coal samples to temperature.The results indicate that with the increase of temperature,the thermal diffusivity of coal samples gradually declined,the specific heat capacity and the thermal conductivity gradually increased.In addition,with the higher temperature,the variation tendency of thermo-physical parameters tended to be weaker.The thermal diffusivity,specific heat capacity and thermal conductivity of ILs-treated coal samples were lower than that of raw coal at the same temperature.Moreover,for a given cation（ ＋ ）,the inhibitory effect of - on the thermal diffusivity was more significant;for a given anion（ - ）,the inhibitory effect of ＋ on the thermal diffusivity was more obvious.The sensitivity analysis shows that the specific heat capacity of coal samples was most sensitive to temperature,whereas the sensitivity of thermal conductivity to temperature was lowest.Furthermore,the specific heat capacity and thermal conductivity of [I]treated coal was relatively lower at the same temperature.The experiment results provide a theoretical basis for the ionic liquid inhibition of coal spontaneous combustion and coal fire heat transfer.