A hybrid peripheral fragmentation and shrinking-core model for fixed-bed biomass gasification

Abstract

Biomass gasification has attracted significant interest as it generates less toxic emissions and the combustion of syngas is more efficient and easier to control than solid fuel combustions. An accurate mathematic model could be used as a cost-effective tool to understand various physical and chemical effects in the gasification process, which is essential for the optimization of thermal efficiency, economic viability and particulate matter (PM) emission reduction. In this work, we have developed a hybrid peripheral fragmentation and shrinking-core model, which considers the intra-particle heat and mass transfer, peripheral fragmentation, porosity evolution and chemical reaction kinetics. The model development involves two steps: the first step is developing a data-driven model to correlate PM emissions with operating conditions based on experimental data; the second step is coupling the PM model in the mass balance of the shrinking-core model to simulate the transient of solid phase mass loss due to peripheral fragmentation. The numerical predictions have been validated with experimental data, and the maximum deviations are 10.24%, 12.95% and 1.47% for syngas, biochar and PM emission, respectively. To the best of the authors’ knowledge, this is the first attempt to quantify syngas generation, biochar production and PM emission in a single model.