Low Temperature Pyrolysis of Graptolite Argillite (Dictyonema Shale) in Autoclaves

The results of the systematic experimental study obtained in this work on the effects of temperature (340–420 °C) and exposure time (0–8h) at nominal temperature on the yield of pyrolysis products from Estonian graptolite argillite (GA) generated in autoclaves without any solvent are described. The yields of solid residue (SR), gas, pyrogenetic water (W) and extractable with benzenemix ofthermobitumen and oil (TBO) were estimated. The compound groups of TBO were assessed. The highest yield of TBO, 2.18% on dry GA basis and 13.2% of organic matter (OM) was obtained at temperature of 420 °C and duration 0.5 h. The main compound groups in TBO obtained at 400 ᵒC are polar hetero-atomic compounds and polycyclic hydrocarbons surpassing 45% and 30% of TBO. The shares of aliphatic and monocyclic hydrocarbons are below 15% of TBO. The yield of W from GA is – about 10-15% of OM. The quantity of OM left in SR after pyrolysis is high, about 65% of OM. The yield of pyrolysis products from GA and the composition of its TBO are compared with those obtained under similar conditions from different oil shales&58; Estonian Kukersite, US Utah Green River, and Jordanian Attarat.