Open source implementation of glued sphere discrete element method and nonspherical biomass fast pyrolysis simulation

Abstract

In this research, a glued-sphere discrete element method was implemented in the open-source, computational fluid dynamics software MFiX. The implementation was verified using a cylinder-wall collision and then validated by simulating the packing and fluidization of nonspherical particles. The validated code was applied to simulate fast pyrolysis of nonspherical biomass particles in a bubbling fluidized bed. The glued sphere occupancy ratio was proposed to quantify the quality of shape resolution using glued sphere. Shape resolution showed significant influence on the packing height in the simulation of particle packing and an occupancy ratio of 80% was recommended. Its influence is minor in fully fluidized bed but can be eight times higher in packed bed. Three tested heat transfer models predicted similar yields of elongated biomass fast pyrolysis. The solver developed in this research can be used to simulate other multiphase reacting flows involving nonspherical particles.

Simulation of Biomass Pyrolysis in a Rotary Drum by Coupling CFD-DEM with a One-Dimensional Thermally Thick Model

“…Gao et al applied a SuperDEM-CFD solver to study the pyrolysis process of cubic biomass particles in a packed-bed reactor. Lu et al . developed a glued-sphere DEM method to investigate the biomass pyrolysis process.…”

“…Gao et al 31 applied a SuperDEM-CFD solver to study the pyrolysis process of cubic biomass particles in a packed-bed reactor. Lu et al 35 developed a glued-sphere DEM method to investigate the biomass pyrolysis process. Wickramaarachchi and Narayana 36 built a three-dimensional Eulerian−Eulerian model and explored the pyrolysis of a single cylindrical biomass particle.…”

Assessment of a detailed biomass pyrolysis kinetic scheme in multiscale simulations of a single-particle pyrolyzer and a pilot-scale entrained flow pyrolyzer

“…The biochar is considered as the sum of all solid residues, including pure carbon, metaplastic species, and ash. The mass fraction of metaplastic in the biochar depends on the biomass residence time in the pyrolyzer, as the "trapped" gases are slowly released from the metaplastics (reaction [22][23][24][25][26][27][28][29][30][31]. Both TGA data and fluidized-bed pyrolyzer data were used to develop the kinetics.…”

“…Mettler et al [23] reported that the convection, conduction, and reaction rates are all within an order of 5 magnitude of one another for a biomass particle with a diameter in the range of 100-1000 microns in a fluidized bed, thus the biomass particles usually can not be assumed isothermal. Particleresolved simulations [24][25][26] have been used to study the effect of intraparticle transport phenomena on the biomass pyrolysis products; however, it is extremely expensive to simulate millions of resolved particles in a practical reactor. Lu et al [27] proposed an offline model to couple the particle-resolved simulations with the reactor model by adding correction factors to the gas-solid heat-transfer and chemical reaction rates.…”

Quantitatively evaluating activity and number of catalytic sites on metal oxide for ammonium perchlorate decomposition

“…Catalytic decomposition of solid phases is a significant fundamental process in energy and environmental technologies, such as coal pyrolysis, 1,2 plastic degradation, 3,4 biomass fermentation, 5 and ammonium perchlorate (AP) decomposition 6–8 . Among these processes, AP decomposition attracts special interest due to its wide application in composite solid propellants (CSPs) for rocket 9 .…”