Effect of Original Minerals on the Pyrolysis of Oil Shale Kerogen

摘要

Oil shales are fine-grained sedimentary rocks that contain organic matter which, upon heating, can be converted to liquid shale oil. The content of inorganic mineral in oil shale is more than 50%, and the composition of inorganic mineral is related to the located area. It is reported that the pyrolysis of oil shale is affected by the mineral content and composition. The oil shale is obtained from Barkol, Xinjiang province. The effect of original mineral and acid treatment shale on the pyrolysis of oil shale is investigated with acid-treatment method and oxide addition method. Oil shale, carbonate-free oil shale, silicate-free oil shale and kerogen samples are analyzed by thermogravimetric analysis (TGA) method. The pyrolysis kinetics of acid-treatment simples is calculated using the overall n order reaction model and Friedman model. The effect of minerals on the distribution of pyrolysates is investigated through pyrolysis gas chromatography mass spectrometry (Py-GC/MS). In terms of activation energy, the original minerals have inhibited effect on the pyrolysis of kerogen. CaO has catalytic effect on the pyrolysis process of kerogen, while MgO has inhibited effect; the effect of Fe_2O_3 is not obvious. The content order of oil fraction under C20 in the pyrolysates ranks as: silicate-free oil shale (OS-F)＞Kerogen＞oil shale＞ Carbonate-free oil shale OS-Cl.