Combustion Characteristics of Lignite Carbonizate and the Possibility of Using It as Power Plant Fuel

Abstract

The involvement of high-calorific fuel, such as carbonized coal, in the country’s fuel and energy balance can have a beneficial effect on the overall saving of solid fossil fuel resources in the production of heat and electricity. To this end, a comparative analysis was carried out, including determination of the main combustion characteristics of Borodino coal and carbonizate obtained by partially gasifying Borodino brown coal at temperatures of 700–800°С in a batch reactor. To do so, the thermal and elemental composition of fuels was determined, and a qualitative assessment of fuel particle surfaces was carried out using the scanning electron microscopy method. Using the thermogravimetric analysis method, the following parameters of coal and lignite carbonizate were determined: the coke residue ignition and burnout temperature, the maximum combustion reaction rate, the mass variation rate at different combustion stages, the exothermic and endothermic reactions intervals, and the maximum heat flux intensity. The effect the release of volatiles has on the combustion process in the course of heating has been noted. It has been shown that the coal carbonizate ignition temperature is by 30% higher than that of coal; the burnout temperature is by 25% higher, whereas the carbonizate specific heating value is 1.8 times higher than that of coal. The accomplished assessment of carbonizate properties has demonstrated the possibility of its use at thermal power facilities as supplementary power plant fuel.