Bitumen is an important organic matter in oil shale and also a vital intermediate product from pyrolysis of kerogen to oil and gas. Soxhlet extraction is employed to obtain bitumen from Green River oil shale

and thermogravimetric analysis (TGA) of the bitumen is carried out under different heating rates. Based on TGA data

isoconversional Friedman method is used to estimate activation energy of bitumen pyrolysis

and the characteristic of activation energy indicates that its pyrolysis most likely involves three processes. Then

bi-Gaussian function is used to deconvolute DTG curves with overlapping peaks into three independent peaks. Subsequently

non-linear least square method is performed to analyze the peaks to estimate activation energies

pre-exponential factors and general forms of reaction models of each process. Comparisons are then made between general forms of reaction models and 11 kinetics models based on four solid-state pyrolysis mechanisms to discriminate reaction models

and results show that the three processes all follow nth-order kinetics model.