Impact of mesophase on the hydrodynamics of a resid hydroprocessor

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Hydroprocessing heavy oil can generate mesophase, a dispersed immiscible liquid phase, occasionally observed in industrial fluidized beds such as the LC-FinerSM operated by Syncrude Canada Ltd. Mesophase is formed due to undesired secondary reactions and can be characterized as polar, denser and more viscous than the continuous liquid phase. This additional liquid phase is believed to negatively affect the operation of the fluidized bed reactor. The goal of this research project is thus to investigate the impact of mesophase and catalyst physical properties on the phase holdups and bed stability, while improving liquid recycle efficiency of the reactor. All elements are interrelated as mesophase may preferentially wet the catalyst, forming clusters that affect bed stability (catalyst sedimentation and/or carry-over) and bubble dynamics, this in turn may affect the ability of the recycle pan to separate the gas from the other phases, which then increases the gas throughput, increasing the gas holdup and rendering the gas separation even more difficult. High gas holdup leads to a lower liquid holdup and residence time, which decreases product yield per unit of total energy required and therefore lowers the overall process energy efficiency. Optimization of economic return and environmental impact are central to the successful development of the Canadian oil-sands industry, which is planned to increase more than twofold to five million barrels of synthetic crude oil a day, or 16% of North American demand by 2030.