KINETIC PARAMETERS OF TORREFACTION PROCESS OF ALTERNATIVE FUEL PRODUCED FROM MUNICIPAL SOLID WASTE AND CHARACTERISTIC OF CARBONIZED REFUSE DERIVED FUEL

Torrefaction is next to drying, pelletizing and briquetting one of the methods for pre-treatment of fuels for later use for energy purposes. Torrefaction is a thermo-chemical process, carried out in the temperature range from 200 to 300 degrees C, under atmospheric pressure and inert gas environment. The study involved a refuse derived fuel (RDF) produced from municipal solid waste in a mechanical-biological plant. The aim of this work was to determine the kinetic parameters of the torrefaction process of RDF and to examine the effect of temperature and the residence time on fuel properties of biochar. Torrefaction process was carried out in the temperature range from 200 to 300 degrees C with the temperature interval of 20 degrees C. The residence was respectively 20, 40 and 60 minutes for each temperature. RDF and the resulting carbonized refuse derived fuel (CRDF) have been subjected to the following analysis: moisture content, organic matter, combustible and volatile content, ash content, and higher heating value. The determined activation energy of RDF torrefaction was 3.71 kJ.mol(-1). The thermogravimetric analysis indicated that during torrefaction, mostly lingo-cellulosic, and hemi-cellulosic biomass present in RDF decomposes during torrefaction. Studies have shown the influence of residence time and temperature on fuel properties of the obtained CRDF. The highest heating value of the CRDF was obtained for the temperature of 260 degrees C, and residence time 20 minutes.