CFD–DEM simulation of biomass gasification with steam in a fluidized bed reactor

Abstract

A comprehensive CFD-DEM numerical model has been developed to simulate the biomass gasification process in a fluidized bed reactor. The methodology is based on an Eulerian-Lagrangian concept, which uses an Eulerian method for gas phase and a discrete element method (DEM) for particle phase. Each particle is individually tracked and associated with multiple physical (size, density, composition, and temperature) and thermo-chemical (reactive or inert) properties. Particle collisions, hydrodynamics of dense gas-particle flow in fluidized beds, turbulence, heat and mass transfer, radiation, particle shrinkage, pyrolysis, and homogeneous and heterogeneous chemical reactions are all considered during biomass gasification with steam. A sensitivity analysis is performed to test the integrated model's response to variations in three different operating parameters (reactor temperature, steam/biomass mass ratio, and biomass injection position). Simulation results are analyzed both qualitatively and quantitatively in terms of particle flow pattern, particle mixing and entrainment, bed pressure drop, product gas composition, and carbon conversion. Results show that higher temperatures are favorable for the products in endothermic reactions (e.g. H2 and CO). With the increase of steam/biomass mass ratio, H2 and CO2 concentrations

Effects of Particle Shrinkage and Devolatilization Models on High-Temperature Biomass Pyrolysis and Gasification

“…Article DOI:10.1021/acs.energyfuels.5b00953Energy Fuels XXXX, XXX, XXX−XXX same for both the gasification and pyrolysis applications. Moreover, the predicted results are also compared to the experimental data available in the literature, 8 and the differences resulting from different particle shrinkage and devolatilization models are highlighted.…”

Numerical simulation of the accumulation of heavy particles in a circular bounded vortex flow

“…The Discrete Element Model (DEM) used in this work is an Eulerian-Lagrangian model, which describes the gas-phase as a continuum, whereas each of the individual particles is treated as a discrete entity (Ku et al 2014(Ku et al , 2015a). The inter-particle collisions are handled through a hard-sphere collision model.…”

Effect of particle size on flow behavior in fluidized beds

“…The solid particles are approximated with Newton's law of motion. This gives high loading to cPu during simulations and is often limited to 2D or quasi-3D and in the order of 10 4 number of particles [19]. The mP PIc modelling is based on the Eulerian approach for fluid particles and lagrangian approach for the solid particles.…”