The paper presents the process of peat burning in a swirl furnace with countercurrent swirl flows and the results of a numerical study. The cyclone-vortex technology of solid fuel combustion allows the furnace volume of a boiler unit, its dimensions and weight to be reduced. The aim of the work is a numerical study of the combustion of pulverized peat in a cylindrical vortex furnace with countercurrent swirl flows. The results of computer simulation of the combustion of pulverized peat with a moisture content of 40%, an ash content of 6% and a higher heat of combustion Q?? = 12.3 MJ/kg are presented. The results of the influence of the design parameters of the furnace and heat load (from 100% to 15%) are given as well. When the heat load is reduced to 15%, the entrainment of unburnt particles increases. The cooled and adiabatic furnace is studied. A significant entrainment of unburned particles is observed n a cooled furnace. The fields of temperature distribution, gas velocity and particle trajectory in the volume and at the outlet of the furnace are determined. The three-dimensional temperature distribution in the furnace volume indicates the combustion of peat particles at temperatures (1300-1450?C). Values of the tangential velocity of a swirl flow near the furnace outlet reach 150 - 370 m/s, which ensures the efficiency of separation of fuel particles and a reduction in heat loss due to mechanical underburning (up to 0.06%). The results of a numerical study show that the diameter of peat particles affects the combustion process, namely coke of particles with an initial diameter from 25 microns to 250 microns burns out by 96%, and particles with a diameter of about 1000 microns are carried away from the furnace and do not burn. The furnace provides a complete combustion of dust particles of peat by 99.8% and volatiles by 100%.

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The aim of this work is to study the working processes of burning the low-quality fuels, namely, the saw dust in the swirling-type furnaces with an opposite twisted motion of the air. The goal was achieved using the physical and mathematical modeling of the flows interaction. The article presented the results of numerical study of aerodynamic characteristics of burning the saw dust in the swirling-type furnace with the opposite twisted air flows. For the research, the facility was used for the saw dust burning with the air supply into the lower and upper zones of burning. The most essential result of the work was modeling of the working process at the ratio of the flows of the primary air and secondary air without the fuel admixture, equal to 0.2. The tangential rate of the flow changed according to the horizontal sections from 3-5 m/s to 40-42 m/s and with respect to the furnace height from 51 m/s to 30 m/s. The average angular rate of the mixture changed relatively the furnace height in the ranges of 171-500 l/s to 100—300 l/s. The significance of the results obtained consists in determination of the possibility of increasing the efficiency of the work of the furnace facilities at the expense of the introduction of the primary and secondary air flows. In this situation, the optimal ratio of consumptions of primary and secondary air was 0.2. Thus, in this work the consumption of primary air was 1.285 kg/s, the consumption of the secondary air was 0.255 kg/s.