Vaporization Parameters of Primary Pyrolysis Oil from Kukersite Oil Shale

The objective of this study was to obtain vapor pressure and heat of vaporization values of the less volatile heavy end of the Kukersite oil shale primary pyrolysis oil and therefore to have a quantitative insight into the vaporization ability of the oil during the pyrolysis process. The shale oil was produced via rapid pyrolysis in a laboratory scale reactor and collected in a solvent filled cold trap. The solvent together with lighter oil constituents were evaporated in a vacuum oven. The prepared low-volatile oil fraction for vapor pressure measurements was estimated to be about 60% by weight of the total oil of pyrolysis. A non-isothermal modification of the conventional Knudsen effusion technique was applied to track vapor pressure as a function of the evaporative loss of progressively heavier oil constituents, starting at a several percent mass loss. From the data, atmospheric boiling point values of progressively less volatile oil were derived, indicating that the boiling point increases above 550 °C (above the retorting temperature) only when about 75 wt% of the oil has vaporized.