Modeling and analysis of single particle conversion of biomass in a packed bed gasification system

• Published in: Applied thermal engineering Vol. 112; pp. 1382 - 1395
• Main Authors: Kumar, Sandeep, Dasappa, S.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 05.02.2017; Elsevier BV
• Subjects: Activation analysis; Activation energy; Biomass; Biomass burning; Biomass gasification; Biot number; Combustion; Conversion; Gasification; Heat conductivity; Heat flux; Heat transfer; Mathematical models; Modeling; Packed bed gasification; Particle size; Physical properties; Pyrolysis; Single particle conversion; Studies; Temperature effects; Temperature profiles; Thermal conductivity; Unity; Weight loss; Pyrolysis; Biomass gasification; Single particle conversion; Packed bed gasification; Modeling
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2016.10.170

•Single particle biomass conversion analysis and modeling for packed bed gasification.•Pyrolysis and char reaction modeled.•Influence of thermo-physical properties analyzed.•Devolatilisation studied under inert and flaming conditions.•Modeling results validated with results from literature. The present study focuses on developing a comprehensive one-dimensional spherically symmetrical model for single particle biomass conversion - a precursor for a packed biomass gasification model. Pyrolysis, volatile combustion and char reactions with a range of reacting species and inert environment are considered in the analysis. Flaming and inert pyrolysis are independently validated with experimental results available in the literature. The influence of thermo-physical properties, like density, thermal conductivity and particle size which affect the Biot number, heat flux, and surface to volume ratio of the particle are studied. Superficial activation energy is proposed to normalize the conversion time with data from different sets of experiments to address the effect of temperature by using a corrected time. Particle with Biot number close to unity suggests a departure from d2 law whereas larger size particle shows close dependence on d2 law indicating a typical diffusion dominated process. The model is compared with a broad range of experimental results available in the literature. The prediction of conversion time, temperature profiles, weight loss rate and model results with normalization to physical parameters, suggests that the predictions with such variability are good enough to be used as a robust model for the packed bed gasification or combustion.