(131c) Direct Numerical Simulation of Biomass Particle Under Fast Pyrolysis Reactor Conditions

Qingang Xiong and Song-Charng Kong

Department of Mechanical Engineering, Iowa State University, Ames 50011-2161, IA, USA

Email: xiong@iastate.edu; kong@iastate.edu

Abstract Direct numerical simulation (DNS) is used in this research to simulate biomass particles when they undergo the pyrolysis process. Fast pyrolysis, a prominent thermochemical conversion approach to produce bio-oil from biomass, has attracted increased interest. But fundamental understanding of biomass pyrolysis is still insufficient. In this study, a DNS method that combines lattice Boltzmann method and discrete element method is formulated to describe the physicochemical evolution of biomass particles in a fast pyrolysis reactor. The lattice Boltzmann method is devoted to simulate the gas phase hydrodynamics while the discrete element method is used to simulate the inter-particle interactions. Different pyrolysis reaction kinetics is employed to describe the chemical reactions. Using DNS, the evolution of biomass particles under fluidized-bed reactor conditions is simulated. The velocity, temperature, and species mass fraction inside and surrounding the particles are presented. It was found that DNS has the ability to reveal the detailed processes associated with biomass pyrolysis and the DNS results can further be used to improve engineering models for reactor simulation.