Pyrolysis Kinetics of a Green River Oil Shale Using a Pressurized TGA

Crushed samples of Green River Oil Shale and its kerogen extract were pyrolyzed at heating rates from 1 to 10 K/min at pressures of 1 and 40 bar and temperatures up to 1000 °C. Two to four mass release peaks were observed with the major two corresponding to kerogen pyrolysis and carbonate decomposition. The transient pyrolysis data were fit with a first-order model and a Distributed Activation Energy Model (DAEM). An F-test was used to determine confidence regions and compare the kinetic parameters among the oil shale and demineralized samples, between the two pressure levels, and between the models. The activation energies determined ranged from 173 to 226 kJ/mol, while the pre-exponential factors ranged from 2.74 × 1010 to 1.86 × 1014 1/s. It was found that there is not a significant difference among the activation energy/pre-exponential factor combinations determined for oil shale and the demineralized samples nor between pressures of 1 and 40 bar. The first-order and DAEM models were also shown to be statistically different, but both models performed well.