Chapter Four - Novel Developments in Fluidized Bed Membrane Reactor Technology

Abstract

Abstract This chapter outlines recent and ongoing investigations on the effect of using membranes in a fluidized bed reactor (FBR), using numerical simulations and experiments. Fluidized bed membrane reactors are a novel, integrated type of reactors where heterogeneously catalyzed reactions can be performed with simultaneous reactant feeding or product extraction in a single unit operation. While this operating technique is beneficial for various reasons (e.g., shift of chemical equilibrium, very good mass and heat transfer), addition or extraction of components can significantly change the behavior of the fluidized bed compared to traditional FBRs, hydrodynamics (bubble and emulsion phase behavior), and mass and heat transfer may be severely affected by the presence of the membranes. A number of experimental measurement techniques are discussed, with a focus on noninvasive optical techniques such as particle image velocimetry and digital image analysis, as well as a number of academic numerical modeling tools such as discrete particle model and two-fluid model. Not only hydrodynamic aspects, such as the emergence of defluidized zones and solids circulation profile inversion, but also the effect on the bubble size distributions are discussed for wall-mounted membranes and horizontally immersed membranes. The development of two novel experimental techniques, which may be used for studying concentration profiles in the gas phase, and for studying the fluidized bed at reaction conditions, are outlined in Section 5 .