PYROLYSIS KINETICS OF ATHABASCA BITUMEN USING A TGA UNDER THE INFLUENCE OF RESERVOIR SAND Pulikesi Murugan, Thilakavathi Mani, Nader Mahinpey* and Mingzhe Dong Department of Chemical and Petroleum Engineering, Schulich School of Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada T2N 1N4 Pyrolysis kinetics of thermal decomposition of bitumen was investigated by thermogravimetric analysis (TGA). TGA experiments were conducted at multiple heating rates of 5, 10, 20 ◦ C min –1 up to 800 ◦ C to obtain the pyrolysis characteristics of bitumen. Weight loss curve from TGA shows that two different stages occurred during bitumen pyrolysis. Differential method has been used for determining the kinetic parameters and the best fit for the order of reaction was found based on the R 2 values. Kinetics results confirm the presence of two different stages in bitumen pyrolysis with varying kinetic parameters. The average activation energy for the first and second stage was 29 and 60 kJ mol −1 and the average order of the reaction was 1.5 and 0.25, respectively. Experiments have been conducted with different reservoir sand. The effect of different source of sand reveals no effect on the pyrolysis behaviour of bitumen. A considerable difference was found with the pyrolysis of bitumen–sand mixtures and bitumen alone based on coke yield and activation energy. Keywords: bitumen, thermogravimetric analysis, pyrolysis, kinetics, thermal cracking INTRODUCTION T he Athabasca oil sands are large deposits of bitumen, located in northeastern Alberta, Canada. More than 95% of the in-place resources of bitumen for North America are obtained from Athabasca (Hein and Cotterill, 2006). In the Athabasca oil sands area, most of the bitumen is hosted within the Wabiskaw-McMurray succession, of which about 82% is con- sidered to be recoverable mainly by thermal in situ methods and 18% by surface mining (Alberta Energy and Utilities Board, 2005). Bitumen (tar or asphalt) is a natural polymer and the low- est grade of crude oil. Bitumens have much higher viscosities and heteroatom compositions than conventional light crude oils. For many years, it has been used for paving applications, con- struction and maintenance of roads. Due to increasing demands and performance, bitumen is now often blended with polymer. Bitumen–polymer blends have a better resistance to cracking in low temperatures, as well as lower flow and deformation in higher temperatures, than that of bitumen alone (Masson et al., 2003). After oil sand is mined, the bitumen has to be recovered from the oil sand in order to upgrade and transport to refiners. At present, several methods may be applied to recover bitumen from oil sand, such as water-based extraction, solvent extraction and pyrolysis (Park et al., 2009). There is a detailed review about bitu- men recovery using water-based extraction reported by Masliyah et al. (2004). Pyrolysis is also widely used by many researchers for the characterisation of the heavy oils using in situ combustion and/or THAI processes (Kok et al., 1998; Meng et al., 2006). Pyrolysis is a process of thermal decomposition of coal, biomass and oil shale in the absence of oxygen to obtain an array of char, oil and gaseous products. Several thermal analysis techniques have been used to obtain the experimental data. The most common and suitable for fundamental kinetic characterisation are ther- mogravimetry (TG). Due to the simplicity of the instrument and calculation methods, the authors have used these techniques to successfully estimate the kinetics of many processes such as pyrol- ysis of crude oil (Murugan et al., 2009a), asphaltenes (Murugan et al., 2009b), and its residue (Murugan et al., 2011), as well as the gasification of char (Mani et al., 2011). Many researchers have used the thermogravimetric analyser to study the thermal decomposition of Alberta oil sand (Park et al., 2009), bitumen (Benbouzid and Hafsi, 2008), and also to investigate the cracking kinetics of pure model compounds (Alshareef et al., 2010). Phillips et al. (1985) carried out the experiments to study the kinetics of ∗ Author to whom correspondence may be addressed. E-mail address: nader.mahinpey@ucalgary.ca Can. J. Chem. Eng. 90:315–319, 2012 © 2011 Canadian Society for Chemical Engineering DOI 10.1002/cjce.20652 Published online 19 September 2011 in Wiley Online Library (wileyonlinelibrary.com). | VOLUME 90, APRIL 2012 | | THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING | 315 |