(390c) Multiscale Simulation of Autothermal Pyrolysis of Biomass

Authors: 
Ciesielski, P. N., National Renewable Energy Laboratory
Pecha, B., NREL
Sitaraman, H., National Renewable Energy Laboratory
Wiggins, G., Oak Ridge National Laboratory
Finney, C. E. A., Oak Ridge National Laboratory
Parks, J., Oak Ridge National Laboratory
Gao, X., National Energy Technology Laboratory
Chandramouli, D., National Energy Technology Lab
Rogers, B., National Energy Technology Laboratory
The variability of biomass substantially exceeds that of conventional feedstocks such as coal due to inherent biocomplexities and inter-species diversity. The impacts of feedstock attributes which are unique to biomass, such as anisotropic, species-specific microstructure, highly variable ash and moisture content, and relatively large particle size distributions are well- recognized by the biomass conversion community. Problems associated with the complexity of biomass feedstocks have been acknowledged by the combustion and biopower communities. However, conventional simulation frameworks for thermochemical conversion of biomass feedstocks employ overly-simplified models that largely neglect the aforementioned complexities and/or apply generalized heuristics which limit their utility to the single feedstock and reactor system for which they were developed. In this talk will describe the development of a multiscale simulation approach that account for the complex size, shape, and chemistry of various biomass feedstock sources. The modeling framework is based on our previously-developed biomass particle pyrolysis simulations which account for the complex, anisotropic transport phenomena exhibited by biomass during thermochemical conversion processes. These particle scale models are coupled to reactor-scale simulations to account for bulk hydrodynamics and residence time distributions. In addition to these physics, we have implemented of a kinetic scheme suitable for biomass combustion and autothermal pyrolysis. I will also provide an update on our efforts to enable direct import of 3D image data of biomass particles into simulation environments and the implementation of adaptive mesh refinement to capture geometric changes that result from pyrolysis and combustion.