Thermogravimetric Characteristics and Pyrolysis Kinetics of Nigerian Oil Sands

Abstract

In the present study, the pyrolysis behavior of Nigerian oil sands was investigated using thermogravimetric analysis. This was done with the aim of deriving kinetic models that can be relevant in the development of the natural resource. The effects of different heating rates (10, 20, and 30 °C/min) on oil sand pyrolysis were studied. The results of the study indicated that three regions comprising low-temperature oxidation, devolatilization, and high-temperature oxidation were obtained at all heating rates. The peak temperatures were observed to rise with an increasing heating rate, a phenomenon described as thermal hysteresis. Mineralogical analysis showed the presence of diffraction peaks corresponding to chlorite, quartz, aragonite, dolomite, calcite, and montmorillonite minerals and the notable absence of expandable clay minerals which are known to pose problems during tailing management and the aqueous bitumen extraction process. The kinetic analysis showed that the activation energy increased with the degree of conversion, with the highest activation energy of 14.682 kJ mol–1. The Coats–Redfern kinetic model gave the best model fit for oil sand pyrolysis.

Pyrolysis of Oil Sand Bitumen Using a Fixed-Bed Reactor: Process Modeling and Compositional Analysis

“…One of the after-effects of the upsurge in global energy demand is an increase in the production of heavy oils. − Heavy oils generally account for more than 30% of world oil reserves. The proven heavy oil reserve is estimated at over 6 trillion barrels, about 6 times more than the 1.02 trillion barrels of conventional light oils .…”