煤中自由基热演化的模拟实验研究

有机质自由基的演化与温度有密切关系,因而可以作为古温标用于沉积盆地的热历史研究.利用36组热模拟实验得到了煤中自由基浓度与其镜质体反射率之间的关系,模拟实验的温度范围为300～550℃,模拟时间为30～480min.实验结果表明,煤中的自由基浓度随煤阶的增加而增大,大约在镜质体反射率为1.75%时达到最大值,随后自由基浓度开始下降.依据模拟实验得到的数据研究了煤中自由基浓度随时间和温度的变化关系,并建立了自由基浓度与时间—温度指数(TTI)的定量模式,该模式可以作为研究沉积盆地古地温的一种新方法.

Experiment study on the thermal evolution of the free radical in coal

There is a close relationship between the evolution of the free radical of organic matter and temperature, therefore, the evolution of the free radical of organic matter can be used as palaeo-temperature scale for studying the thermal history of sedimentary basins. The relationship between the free radical concentration and the vitrinite reflectance of coal is obtained through 36 anhydrous pyrolysis experiments in laboratory. The experimental temperature ranges from 300℃ to 550℃ and the experimental time ranges from. 30 min to 480 min. The results of the experiments show that, the free radical concentration of coal increases at first and then decreases with the increase of coal rank, and it reaches to a maximum value when the vitrinite reflectance equals 1.75 % . The variation of the free radical concentration with experimental temperature and time is investigated according to the experimental data. The relationship between the free radical concentration and temperature -time index is established using temperature-time index integral equation of Waples. The relationship can be used for studying the palaeogeotherm of sedimentary basins.