Myroshnik M. Kinetics of thermal destruction of some types of biomass as alternative fuel

Dissertation is dedicated to the study of thermo-chemical decomposition of some biomass types as alternative fuel for pulverized combustion in furnaces of power plant boilers. The experimental research of thermal degradation some types of solid biomass has been carried out. TGA method and experimental unit were employed. Experimental data thus obtained were digitalized and processed by means of application of the integral and differential methods. A set of kinetic coefficients for the Arrhenius Equation of the reaction first order were obtained valid within the temperature range characteristic for the preliminary stage of combustion process, namely - biomass demoisturization and devolatilization. A mathematical model, which allows calculation of the stages named above duration, biomass particles change due to the moisture evaporation and volatiles yield, biomass heating up time rate, determination of total mass of volatiles yield, heat balances of the processes has been developed. The model has been validated by the experimental data obtained as well as by the data available in literature. It has been shown that the results calculated by the model correspond to experimental data with an accuracy ±9 %, and can be used directly for description of water evaporation processes and volatiles yield. It can also be used as a sub-model of biomass combustion as a single fuel and co-combustion with pulverized coal. The process of biomass pulverized combustion as an alternative fuel and co-firing of biomass with coal in the pilot experimental stand VGP-100 has been studied. The prospect of natural gas substitution by biomass fuel for the flame stabilization has been proven. The mathematical model of heating and water evaporation, devolatilization was developed in application to the pulverized combustion on the pilot stand of VGP-100.