(161c) Application and Challenges of Numerical Simulations in Modeling and Scale-up of Circulating Fluidized Bed Reactors

Circulating fluidized bed (CFB) reactors have a long history of commercial applications ranging from coal gasification and Fluid catalytic cracking (FCC), to newer applications such as catalytic conversion of methanol to olefin (MTO) and even CO₂ Capture using solid sorbents.

Like any other technology, there are challenges in the way of scale-up, deployment and optimization of this technology, based on the lab or bench scale studies. On the other hand, despite of the long history of circulating fluidized bed operations in mature technologies such as Fluid Catalytic Cracking (FCC), complete understanding of the origin and nature of the inherently complex flow structures observed in these devices is still lacking. Adding chemical reactions to the picture makes it even more complex. Therefore, beside experimental studies, advanced and rigorous numerical modeling, i.e. computational fluid dynamics (CFD), is essential to shed light on the complex behavior and flow structure in these systems and to bridge the gap between lab/bench scale and large commercial scales.

In this talk, the strengths and shortcomings of the existing mono-disperse continuum models in simulations of fluidized bed reactors will be reviewed. The needed improvements in the inter-phase exchange properties, frictional viscosity and considering the effect of polydispersity through a novel mathematical approach, will also be discussed.