Reactivity of chars gasified in a fixed bed reactor with the potential utilization of excess process heat

The aim of the work presented in this paper was to determine the reactivity of chars and their selection for further research purposes concerning coal gasification processes with the utilization of process excess heat. Char reactivity can be defined as the ability of coal to react with such reactants as steam, oxygen or carbon dioxide. Reactivity determines reaction rates and therefore it is a decisive factor relating to the efficiency of combustion and gasification processes. In light of the above, reactivity may be regarded as an important parameter to be considered in the design and operation of the industrial systems of coal processing. The experimental work was conducted by means of a thermogravimetric analyzer (TGA) at temperature ranges of 700, 800 and 900 °C, with oxygen as a gasifying agent. The parameters of maximum reactivity Rmax as well as of 50% of the conversion reactivity R50 were calculated. The times tmax and t50 necessary for attaining the maximum reactivity Rmax and 50% conversion reactivity R50 were also determined. The correlation between the experimentally determined values of Rmax, R50,tmax and t50,additionally the physico-chemical parameters of the coals were examined by means of PCA analysis.