A generalized correlation for coal devolatilization kinetics at high temperature

• The devolatilization of 20 coals is studied at high temperature and heating rate.
• A simple model is adopted to be applied to CFD codes of large thermochemical plants.
• A generalized correlation between kinetics and coal properties is validated.

The optimization of thermochemical (combustion, gasification, pyrolysis, oxyfiring) systems requires a comprehensive model, able to simulate conventional and innovative plants, for achieving the high levels of efficiency and low pollutant emissions required by the current applications. A devolatilization model is the basis of these processes and should be sufficiently simple and accurate to be implemented in commercial codes for simulating large scale plants. Kinetic parameters should be validated in qualified tests under severe thermal conditions and for coals of different ranks. In this work the experimental data from the isothermal plug flow reactor of IFRF (with temperatures up to 1673 K and heating rates on the order of 104 K/s), previously uniformed and organized in the solid fuel database SFDB, are elaborated to obtain the kinetic parameters according to a modified version of the single first order reaction model. The effective thermal history of the particles is estimated by simulating the devolatilization tests with a CFD model. A generalized correlation is obtained between the kinetic parameters and coal properties, preferably among those routinely reported in standard analyses. Finally, a practical and useful predictive tool is provided for studying the devolatilization of pulverized coal.