煤压力热解的差热法研究

A STUDY OF THE PRESSURE PYROLYSIS OF COAL BY DTA METHOD

热解是多种煤转化技术的基础,研究煤的热解有助于煤的有效加工利用;而且煤的热解模拟实验方法是研究煤自然演化生油气过程地球化学特征的重要手段之一,对于寻找和鉴别煤型油气,估算煤型油气储量具有较大意义。中外学者对煤的热解进行了大量研究,实验大都是在常压下进行的。而当今一些煤的加工生产过程常常要在加压条件下进行,压力成为煤加压气化、加压液化等技术中的重要参数,但目前这方面的研究还较少,尚需做进一步的工作。本文利用压力差热分析仪(DTA)对煤样做了压力热解实验,根据所得煤样在一系列压力下的热解图谱,分析了压力对煤热解的影响,并对煤的压力热解机理进行了初步探讨。

For the studying of the pressure pyrolysis characteristics of coal,pressurized pyrolysis experiments on candle coal and brown coal were carried out by means of high pressure differential thermal analyzer(DTA).Their DTA curves of pyrolysis were abtained at the linear heating rate of 10℃/min with the final temp.of 650℃ under the pressures of 0.1,1.0,2.0,3.0,4.0,5.0,6.0MPa respectively.It was found that there are two endothermic and one exothermic peaks in the pressure pyrolysis DTA curveshe.The first endothermic peak before 200℃ is caused by the desorption of surface water in coal.The second endothermic peak in the range of 250—450℃ is due to the pyrolysis reaction.And the condensation and carbonization reactions are responsible for the exothermic peak above 450℃.The effects of pressure on coal pyrolysis were discussed and the high pressure pyrolysis mechanism of coal was tentatively approached.It was shown that the pyrolysis reaction is predominated in the former stage of coal pyrolysis,but the condensation arid carbonization reactions are important in the later atage.Carbonization reaction is enhanced by pressure.