(349g) Reaction-Transport Model for the Pyrolysis of Shrinking Cellulose Particles

A reaction-transport model is developed for the pyrolysis of non-porous cellulose particles.  The model includes recently measured kinetic parameters, intra- and extra-particle heat transfer, and particle shrinkage as gaseous products are formed.  The intra-particle temperature gradient, which gives rise to spatially-varying reaction rates, is mainly influenced by the initial particle size, the external temperature, and the heat transfer coefficient.  Numerical predictions for measurable properties, including the temporal evolution of the residual mass and the final char yield, are validated through comparison to data from experiments for various particle sizes, and excellent agreement is found.  Predicted char yields and effectiveness factors are presented for a wide range of parameters, and operating conditions are identified under which the process is transport vs. reaction controlled due to the limitations of intra-particle heat transport.