Thermal characteristics of bitumen pyrolysis

The pyrolysis behavior of bitumen was investigated using a thermogravimetric analyzer-mass spectrometer system (TG-MS) and a differential scanning calorimeter (DSC) as well as a pyrolysis-gas chromatograph/mass spectrometer system (Py-GC/MS). TG results showed that there were three stages of weight loss during pyrolysis-less than 110, 110-380, and 380-600 A degrees C. Using distributed activation energy model, the average activation energy of the thermal decomposition of bitumen was calculated at 79 kJ mol(-1). The evolved gas from the pyrolysis showed that organic species, such as alkane and alkene fragments had a peak maximum temperature of 130 and 480 A degrees C, respectively. Benzene, toluene, and styrene released at 100 and 420 A degrees C. Most of the inorganic compounds, such as H-2, H2S, COS, and SO2, released at about 380 A degrees C while the CO2 had the maximum temperature peaks at 400 and 540 A degrees C, respectively. FTIR spectra were taken of the residues of the different stages, and the results showed that the C-H bond intensity decreased dramatically at 380 A degrees C. Py-GC/MS confirmed the composition of the evolved gas. The DSC revealed the endothermic nature of the bitumen pyrolysis.