The investigation on evolution of coal char structure during pressurized pyrolysis can reveal the combustion reactivity of coal char in thermal utilization at elevated pressure. In this study, Zhundong subbituminous coal was demineralized and a pressurized drop tube reactor (PDTR) was used to prepare coal char under different temperature and pressure conditions. The physicochemical structures of raw and demineralized coal chars were characterized by the application of nitrogen adsorption analyzer, automatic mercury porosimeter, and Fourier transform infrared spectroscopy (FTIR). The change mechanism of char infrared structure with pyrolysis pressure is revealed on the molecular level in this paper. The results show that the N₂ adsorption quantity of raw coal char increases with the increase of pyrolysis temperature, while that of demineralized coal char decreases. Because of the difference in molecular volume and steric hindrance between aliphatic and aromatic structure in char, the increasing pressure has less inhibition effect on the escape of the former than the latter. With the increase of pyrolysis pressure, the combustion reactivity of char is related to the infrared structure at 700 and 800 °C while to macropore structure at 900 and 1000 °C.

对加压热解过程中煤焦结构演变的研究可以揭示煤焦在高温热利用中的燃烧反应性。在这项研究中，准东亚烟煤被脱盐，并且使用加压降管反应器（PDTR）在不同温度和压力条件下制备煤焦。通过应用氮吸附分析仪，自动水银孔率计和傅里叶变换红外光谱（FTIR）来表征原煤和软化煤焦的理化结构。从分子水平揭示了焦炭红外结构随热解压力的变化机理。结果表明，N ₂随着热解温度的升高，原煤焦的吸附量增加，而软化煤焦的吸附量减少。由于炭中脂肪族和芳香族结构之间的分子体积和空间位阻的差异，增加的压力对前者的逸出的抑制作用小于后者。随着热解压力的增加，炭的燃烧反应性与700和800°C下的红外结构有关，而与900和1000°C下的大孔结构有关。