Abstract: “Liquefaction of Kukersite and Dictyonema oil shales originating from Baltic deposits and varying by kerogen content and chemical composition were pyrolysed in a Fischer assay with the aim to maximize liquid product yield being determined as a sum of volatiles (oil) and solubles (thermobitumen). The effect of temperature in the range of 320–490 °C during 20 and 60 min residence time on the yield of thermobitumen, oil, gas, solid residue and water was studied. The chemical group and individual composition of the compounds in the liquid product such as aliphatic hydrocarbons, monoaromatic hydrocarbons, polyaromatic hydrocarbons, low-polar heteroatomic compounds and high-polar heteroatomic compounds were estimated by using TLC and GC/MS-methods. Varied temperature-time regimes used in modified Fischer assay analysis yield thermobitumen and oil in different proportions the sum of those being considerably higher compared with standard Fischer assay pyrolysis. Up to 90% of Kukersite kerogen w”

Keywords: modified Fischer assay pyrolysis, kerogen, thermobitumen, shale oil, yield