Modeling the Fluid Dynamics of a Commercial Ebullated Bed Hydroprocessor

Ebullated bed hydroprocessors are a widely adopted technology for the upgrading of heavy oil. Because of the energy-intensive nature of this process, improvements and optimizations are highly desirable. As such, a complete understanding of the complex multiphase fluid dynamics in these units is still required to provide insight for future performance improvement. Specifically, current literature has not addressed the performance of the internal gas–liquid separation within the reactor and the impact of resulting entrained gas on overall reactor fluid dynamics. In this study, a novel numerical fluid dynamic model for a commercial scale ebullated bed hydroprocessor is proposed. A liquid residence time-based gas–liquid separation model is shown to be representative through analysis of commercial operating data. Freeboard gas holdups are predicted within 4% points for two generations of liquid recycle pans. Recycle pump speed is estimated within 10% points for the flow through pan.