Investigation of Low-Temperature Copyrolysis of Organic Matter from Huadian Oil Shale and Indonesian Lignite

The mixture of lignite (HM) and oil shale organic matter (OS), which was prepared from Huadian oil shale treated using acids, was copyrolyzed in a fixed-bed reactor at the temperatures of 350‒500°C. Gas chromatography, thermogravimetric analysis, and in situ Fourier-transform infrared (FT-IR) spectroscopy were used to characterize the pyrolysis products. The results showed that the experimental yields of solid product and hydrogen obtained from the copyrolysis were higher than the theoretical values, respectively. The in situ FT-IR results showed that the emissions of ‒OH, aliphatic C‒H_x, and C–O groups for HM, OS, and their mixture all increased with increasing temperature. Moreover, a microscopic description of the low-temperature pyrolysis of HM and OS is provided. OS contains a large content of aliphatic compounds that can produce enough H radicals to bind to the H-poor radicals produced from HM. The coupling of these two free radicals resulted in a decrease in the yield of H₂, while an increase in the yield of solid product was obtained.