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The process of steam gasification of three coals of various rank and three chars obtained from these coals by the ex-situ method at 900 °C was compared. In the coal gasification process, the pyrolysis stage plays a very important part, which is connected with its direct impact on the kinetics of gasification of the resulting char. What is more, taking into consideration the impact of pyrolysis conditions on char properties, it should be anticipated that the gasification kinetics of coal and char, formed from it by the ex situ method, will be different. In order to examine and compare the process of gasification of coals and chars, an isothermal thermovolumetric method, designed by the authors, was applied. For all the examined samples the measurements were performed at three temperatures, i.e. 850, 900, and 950 C, and at the pressure of 0.1 MPa. An evaluation of the impact of raw material on the steam gasification of the examined samples was made. The carbon conversion degree and the kinetic parameters of CO and H2 formation reaction were calculated. It was observed that the course of gasification is different for coals and chars obtained from them and it can be concluded that coals are more reactive than chars. Values of kinetic parameters of carbon monoxide and hydrogen formation calculated for coals and corresponding chars are also different. Due to the observed differences the process of gasification of coals and of chars with steam should not be equated.

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Combustion and co-combustion of biomass from different sources is one of the most popular technologies applied in Poland. It allows management of numerous industrial, communal and agricultural waste. Organic waste constitutes one of the richest sources of cheap biomass solid fuels since they are very popular. The paper includes an assessment of practical use of biomass waste: hazelnut shell and pistachio nut shell. The impact of pyrolysis temperature (300, 450 and 550ºC) of the investigated biomass on the quality of the obtained biochar was determined and the optimal temperature of this process was defined. The quality of the investigated biomass was analysed on account of its use for energy purposes. Numerous advantageous properties of the obtained materials were found out, for instance: low content of ash and a noticeable increase of the calorific value with an increase of the pyrolysis temperature.