Solvent swelling of Dictyonema oil shale: Low temperature heat-treatment caused changes in swelling extent

Equilibrium swelling experiments were used to gain insight into the structural changes of Dictyonema oil shale kerogen (baltoscandian basin black shale kerogen) during low-temperature heating. Room temperature volumetric swelling was measured for samples previously thermally pre-treated at different temperatures under an inert gas environment. The swelling capacity for heat-treated Dictyonema oil shale decreases with increasing pre-treatment temperature from about 150 °C to 380 °C, suggesting that cross-linking reactions occur during low-temperature heat treatment in the pre-pyrolysis temperature region. This behavior is consistent with that observed in non-softening low-tar yield coals.