Influence of the end-temperature on the oil shale fast pyrolysis process and its products

Fast pyrolysis of the oil shale type kerogenous fuels is a novel way to produce shale oil with different properties depending on the process conditions. Until now, little has been known about the fast pyrolysis process of Estonian oil shale. This study focused on the fast pyrolysis process, the evaporation of gases and the properties of the solid residues produced during Estonian oil shale fast pyrolysis. The end-temperatures of the process were varied from 303 to 825 °C, thereby producing semicokes where the organic matter had different decomposition grades and the carbonate minerals exhibited different degrees of degradation. SEM, ATR-FT-IR and XRD analysis were performed to describe the differences between the produced materials. HHR-TGA-MS analysis revealed that the evaporation of H2S can be decreased by lowering the pyrolysis temperature below 490 °C. ATR-FT-IR analysis showed that structural changes in the methyl- or methylene groups of the organic matter occurred mainly in the temperature range of 385–439 °C.