The heat and mass transfer in a large lignite coal particle devolatilizing in FB

Abstract

A theoretical study has been performed in order to investigate heat and mass transfer processes in a lignite particle during the devolatilization. A mathematical model, describing the devolatilization process, has included the internal and external heat transfer, primary decomposition reactions and mass transfer. The input of the numerical model has been: coal thermal properties, chemical kinetic parameters, particle diameter, volatile matter amount, and fluidized bed temperature. The output includes: the temperature, the amount of volatiles released, the rate of devolatilization, volatile matter flux, and the pressure inside the particle. The model enable closer insight of transfer processes within the lignite particle, devolatilizing in FB, and shows how the FB temperature and original size of coal reflect on the pressure profile of the lignite particle, devolatilizing in FB.