Comparison of 1D and 3D models for the thermochemical conversion of carbonaceous pulverized particles

Abstract

Accurate modeling of thermochemical conversion of carbonaceous particles is essential for predicting solid conversion behavior in high temperature industrial reactors. Numerical efficient 0D or 1D particle models are widely used in large-scale CFD simulations. They typically rely on simplifying assumptions regarding intra-particle heat and mass transfer and chemistry. In contrast, fully resolved 3D multi-region particle models capture detailed transport and reaction phenomena but are computationally expensive. In this study, we compare a 1D particle-resolved Lagrangian model with a detailed 3D multi-region model implemented in OpenFOAM to assess their predictive capabilities under realistic conditions. Three particle sizes and three conversion temperature profiles were analyzed. The comparison focuses on the temporal evolution of the conversion and the intra-particle states at 50% devolatilization and 50% burnout. The results indicate that the 1D and 3D model predict similar mean temperature profiles for most cases, while the mean conversion profiles differ. The results indicate that the 1D model results are biased by the employed sequential thermochemical conversion model for high temperature cases. Some of the differences might be also caused by the slightly inconsistent model settings between the 1D and 3D models. The more complex 3D model requires additional parameters and the devolatilization model from the 1D model is not supported by the 3D modeling framework.