松辽盆地沙河子组煤岩TG-MS实验产物特征及动力学分析

针对目前煤系烃源岩评价中热解实验温度较低无法揭示高演化阶段生气特征这一现状，采用TG-MS（热重-质谱联用仪）高温热解仪研究煤岩热解产物特征，并结合化学动力学模型开展烃类气体生成动力学分析。结果显示：煤岩质量损失达40%，可分为3段，即水分及吸附气体的损失、大分子键断裂损失和芳香结构的缩聚反应损失。甲烷在300 ℃左右开始生成，480 ℃时生成速率最大，在850 ℃左右生甲烷结束，比生成其他烃类结束温度要高。苯析出曲线呈双峰特征，且芳香族类和脂肪族类产物生成受控于相同的化学反应。煤岩热降解生气化学动力学模型参数及应用结果表明：随着烃气分子量的降低，生成活化能依次增大，生成时间逐渐变晚。同时煤岩持续生气时间较长，无主生气期。

Pyrolysis products characteristics and kinetic analysis of coal from Shahezi Formation of Songliao Basin under the TG-MS experiment

Aiming at the gas generation characteristics of coal measures source rock during the high evolution stage,which cannot be investigated by the common pyrolysis equipment,the TG-MS(thermogravimetry-mass spectrometry) equipment was employed to study the pyrolysis products characteristics of coal,and then hydrocarbon gases generation kinetic behaviors were investigated.The results show that the mass loss of coal can reach 40%,and can be divided into three stages:moisture and adsorbed gas loss,macromolecule bond cracking loss and the poly-condensation of the aromatic structure loss.Methane starts to generate at about 300 ℃,and its generating rate reaches the highest value when the temperature reaches 480 ℃.The termination temperature of methane is about 850 ℃,which is higher than that of other hydrocarbon gases.The aromatic and aliphatic products are controlled by chemical reactions with the same functional groups,and the benzene evolution curve shows double peaks.Kinetic model parameters of hydrocarbon gases from coal degradation and the geological application results show that the generation activation energy increases with the decrease of gas molecular weight,and the lower molecular weight of hydrocarbon gas,the later of the generation time.The hydrocarbon gas generation history also shows that the gas generation time is long and no major generation period.