Thermal dissolution of Estonian oil shale

The thermal dissolution of Estonian oil shale, kukersite and thermobitumen (TBO) formed, in the presence of solvents (benzene, ethanol, water and oil shale petrol) in autoclaves was studied. In all the solvents, except subcritical water, the total yield of benzene-soluble products, TBO, has a maximum (about 90%) at an optimum residence time and thereafter decreases due to coke formation. The formation of TBO from kukersite in supercritical water, ethanol and oil shale petrol is accelerated in comparison with low-temperature pyrolysis of kukersite without any solvent. The tests carried out with TBO without the mineral matter indicate deceleration of the coke formation in comparison with the initial kukersite.