A pyrolysis process of different coal samples into three different types of oxidizing medium (argon, air and steam) were studied by means of thermogravimetry. Two coal types with different metamorphism degree (lignite and bituminous coal) were used. The experimental procedure was carried out in non-isothermal conditions in temperature range from 373 K to 1273 K with 20 K/min heating rate. Purge gas consisted of argon and oxidizer with volumetric ratio 1:24 and had 250 ml/min flow rate. Kinetic parameters were defined by fitting procedure using Arrhenius-type equation with the first order reaction rate on conversion distribution function. The ignition and burnout indexes were calculated to evaluate sample reactivity at different oxidizing mediums. The highest reactivity values in same atmosphere were obtained for lignite because of higher particle special surface area. For same samples the higher reactivity was obtained in steam medium. The conclusion about some kind of synergy between carbon oxidation and pyrolysis could be made.
ASJC Scopus subject areas
- Materials Science(all)