Pyrolysis of asphaltenes in an atmospheric entrained flow reactor: A study on char characterization

• Asphaltenes were pyrolysed in an entrained flow reactor at varying conditions.
• Global gasification reactivity of chars obtained from pyrolysis decreased with increase in temperature.
• Changes in char structure and composition could explain the variation in reactivity.
• Increase in residence time had marginal decrease in char reactivity.

Integration of solvent deasphalting and asphaltenes gasification has been reported as a convenient alternative to coker based upgrading of bitumen, derived from oil sands. However, very limited work has been carried out on pyrolysis and gasification of asphaltenes at entrained flow conditions. The present study aims at addressing this gap, and provides a better understanding of the major intermediate in gasification process – char. Chars were prepared at different operating conditions in an atmospheric entrained flow reactor. Extensive characterization techniques were used to identify the changes in morphology, structure and composition of chars. We estimated the global gasification reactivity of chars with steam and CO2. Chars exhibited an internally hollow structure with porous walls. The nominal size of individual char particles and degree of fragmentation were greatly influenced by the operating conditions. H/C ratio, aromaticity and macro-porosity of chars increased with an increase in operating temperature, while content of heteroatoms and global reactivity showed a gradual decrease. Increase in residence time had marginal effect on char composition, morphology and global reactivity. V and Ni tend to accumulate in chars; however, their effect on global reactivity could not be established.