No abstract

No abstract

No abstract

The aim of this study was to analyse the steam gasification process of ‘Janina’ coal with and without Na-, K- and Ca-catalysts. The catalysts were physically mixed with the coal due to the simplicity of this method, short time of execution and certainty that the amount of catalyst is exactly as the adopted one. The isothermal measurements were performed at 800, 900 and 950°C and a pressure of 1 MPa using thermovolumetric method. The obtained results enabled assessment of the effect of analysed catalysts on the process at various temperatures by determination of: i) carbon conversion degree; ii) yield and composition of the resulting gas; and iii) kinetics of formation reactions of main gas components – CO and H2. The addition of catalysts, as well as an increase in operating temperature, had a positive effect on the coal gasification process – reactions rates increased, and the process time was reduced.

The thermogravimetric method allows to carry out measurements both in isothermal conditions for a given temperature and in non-isothermal conditions at a set heating rate. The aim of the work was to compare the process of gasification of the same coal in an atmosphere of CO2 under isothermal and non-isothermal conditions. The measurements were carried out with the use of DynTHERM Thermogravimetric analyzer by Rubotherm. Char derived from Polish bituminous coal “Janina” was used as material for gasification. In case of the isothermal method the measurements were performed at three temperatures – 850 °C, 900 °C and 950 °C, while in case of the non-isothermal method for three heating rates, i.e. 3 K/min, 5 K/min and 10 K/min. Based on the results obtained, kinetics curves of conversion degree of the gasification process were developed and kinetic parameters of the gasification reaction i.e. reaction order, activation energy and pre-exponential factor were determined. The values of the kinetic parameters obtained from measurements performed in isothermal and non-isothermal conditions were compared.