**5. Acknowledgment**

726 Mass Transfer - Advanced Aspects

1 10 100 1000 10000 **Particle Diameter, nm**

Fig. 9. Percentage of deposited particles at the bottom of the cylindrical channel (%*Mdep*) at different temperatures and particle diameters for the deposition of MoO3 particles immersed

The results from these simulations unveiled the particle diameter and fluid medium properties that are necessary to ensure particle suspension and mobility in bitumen. In the case of the spherical storage tank simulation, it was found that MoO3 particles smaller than 150 nm will remain suspended in bitumen at temperatures from 340 to 380 °C after a long period of time (27778 h) Also, it was shown that the percentage of deposited particles at the bottom of the tank after this period of time is less than 0.02 % when particles diameters

Regarding the simulations applied to the flow of particles through a horizontal pipeline, the results demonstrated that particles smaller than 150 nm will remain flowing through bitumen after a long period of time (4167 h) in the range of temperatures from 340 to 380 °C. In addition, the modelling results showed the percentage of settled particles at the bottom of the cylinder after this period of time when a particle deposition scenario is presented. It was observed that less than 0.1 % of the total mass of particles (that passed through the cylinder

Based on these results, it seems that when MoO3 catalytic particles with diameters lower than 400 nm (nanometric range) are immersed in bitumen either in a stagnant or a flow scenario, almost all the particles will remain suspended in the system. Therefore, this kind of particles could be employed as ultradispersed catalysts for bitumen hydroprocessing reactions. It would be interesting to compare these models with experimental data from real systems; however, on line tools for the particle concentration measurement would have to

during this time), with diameters lower than 400 nm, were deposited at the bottom.

0

**4. Conclusion** 

below 200 nm are utilized.

0.1

0.2

0.3

0.4

**%** 

*Mdep*

0.5

0.6

0.7

0.8

340 °C 350 °C 360 °C 370 °C 380 °C

in Athabasca bitumen flowing through a pipe

be developed in order to achieve this objective.

This work was supported in part by the National Council for Science and Technology of Mexico, The Alberta Ingenuity Centre for In Situ Energy funded by the Alberta Ingenuity Fund and the industrial sponsors: Shell International, ConocoPhillips, Nexen Inc, Total Canada and Repsol-YPF, and The Schulich School of Engineering at the University of Calgary, Canada.
