MATHEMATICAL-MODELING OF DEVOLATILIZATION OF LARGE COAL PARTICLES IN A CONVECTIVE ENVIRONMENT

A generalized model for devolatilization of large coal particles typic ally encountered in a gasifier has been developed. The model predicts a time-temperature history of the particle in a convective heat transf er environment. Thermal decomposition of volatile matter is treated as a series of independent chemical reactions in which the rate constant s differ only in activation energy. The activation energy is expressed as a Gaussian distribution. Experimental data obtained in a flow reac tor are presented and used to validate kinetic and transport parameter s of the model. Devolatilization time predicted by the model with upda ted parameters is also compared with that obtained from a pilot fixed- bed gasifier.