Modeling Light Gas and Tar Yields from Pyrolysis of Green River Oil Shale Demineralized Kerogen Using the Chemical Percolation Devolatilization Model

Recent detailed chemical structure analyses of three demineralized kerogens from Green River oil shale samples were used to generate input parameters for the chemical percolation devolatilization (CPD) model. This model uses a lattice network to describe pyrolysis of solid hydrocarbons, such as coal and biomass. It was necessary to modify the formulation of the CPD model to account for the long aliphatic carbon chains found in oil shale, because gases formed from these long chains condense at room temperature and are counted as tar. It was initially assumed that 20% of the aliphatic material was released as light gas during formation of stable char bridges, leaving 80% of the aliphatic material to form side chains that would later be released as heavier condensable gas. With slight adjustments to the kinetic coefficients, calculations from the reformulated model agreed well with tar and light gas yields reported for these same demineralized kerogens at 10 K/min. The calculation of bridge parameters showed...