Examinations of Polish brown and hard coals in terms of their use in the steam gasification process

In order to determine the suitability of Polish coals for steam gasification, five Polish hard coals and three brown coals, which are used for power and heat production, were examined in this work. The examinations of the process of steam gasification were conducted with the use of a laboratory plant which allows for measurements within a broad pressure range with the thermovolumetric method. Reactivity evaluations for the examined coals were conducted on the basis of an analysis of the shape of the kinetic curves of formation of major gasification products and a comparison of the curves of the carbon conversion degree of the examined raw materials. In order to evaluate the reactivity of the examined coals, the following factors were utilized: a comparison of the shape of the curves of the carbon conversion degree and the maximal value of the carbon conversion degree, the time of partial conversion τ0.5, the reactivity index R0.5, as well as the reaction rate constant of carbon conversion. The yields, composition and calorific value of the resulting gas were determined as well as the reaction rate constants of formation of particular gaseous products of gasification. Additionally, for the examined coals, ash fusibility and the content of selected impurities, e.g. sulfur, chlorine and mercury, were given.