Chapter 5 - Reactor Performance and Scale-Up

Abstract

This chapter provides a methodology for the engineering of trickle bed reactors such as to enhance performance and scale up production. In engineering practice, the reactor engineering solution is composed of three main steps: analysis of transport and reaction rate parameters; identifying uncertainties associated with design parameters; and resolving process complexities and conflicting demands. In trickle bed reactors, interaction between reaction kinetics and hydrodynamics is often complex. Key practical aspects involving rate analysis including hysteresis and multiplicity, particle and bed properties (particle size/shape/orientation), distributor effects, liquid phase maldistribution, and mixing of phases along the length of the column are discussed. Issues related to selection of reactor aspect ratio and issues pertaining to scale-up and scale-down are also discussed. An overall methodology combining experiments and computational modeling is presented at the end. It is evident from the current state of the art that in spite of the considerable advances in the understanding of different phenomena occurring in trickle beds, it is futile to attempt a single comprehensive model for a trickle bed reactor incorporating all the processes. It is therefore recommended to use a suite of models comprising many “learning” and “design” models. These modeling efforts need to be complemented by appropriately designed experiments of three categories: learning, calibration, and validation. Such a composite approach based on the methodology discussed will be useful for the engineering of trickle bed reactors.