Numerical Study on Fast Pyrolysis of Lignocellulosic Biomass with Varying Column Size of Bubbling Fluidized Bed

Abstract

A fundamental understanding of the complex hydrodynamic characteristics in a reactor and its pyrolysis reaction field is required to elucidate the physical phenomena occurring in a bubbling fluidized bed (BFB) pyrolyzer. Specifically, bubble behavior is a very important factor for hydrodynamics, solid mixing, and consequent pyrolysis reaction. Accordingly, this study performed modeling and simulation of the BFB pyrolyzer using the computational fluid dynamics method with an Eulerian–Eulerian approach with kinetic theory. The hydrodynamic and pyrolysis characteristics of the reactor were also investigated. A two-stage semiglobal kinetics was applied to model the fast pyrolysis reaction of the lignocellulosic biomass. The dimensions of the fluidized bed column were varied to examine how the bubble size and the column shape affect the pyrolysis reaction. Changing the dimension physically confined the size and number of gas bubbles. Moreover, the primary and secondary reaction rates for the pyrolysis reaction...