Ignition of two-component and three-component fuel mixtures based on brown coal and char under slow heating conditions

The paper presents a comparison of combustion processes of two- and three-component fuel mixtures based on char and two brown coals with different technical and elemental composition, applying thermogravimetric analysis in an air flow, at a heating rate of 20 °C min −1 . From the mass loss, mass change rate (TG/DTG) curves showing the combustion process of the fuels, the following characteristics were determined: ignition temperature, burnout temperature and combustion index. Using differential scanning calorimetry (DSC) curves, endothermic and exothermic effects as well as maximum heat flux intensities during fuel combustion were determined. Based on the results of these studies, a linear dependence of the combustion index on the combustion heat of two- and three-component fuels was established for the first time. An increase in the calorific value of the fuel mixture by more than 7% affects a decrease in the combustion index to 100%. A maximum percentage of char not exceeding 20–30% added to two- and three-component fuel mixtures, exceeding which will entail a reduction in the combustion characteristics of the mixtures has been established. It is noted that three-component fuel mixtures are promising for practical application, as the addition of two high-reaction and high-energy fuel components to the base fuel has a positive effect on increasing the energy characteristics of the mixture and reducing the duration of the induction period.