## 3 Results and Discussion
The second reason is that sulfur and nitrogen oxides interact with water vapors, as well as biomass pyrolysis and gasification components. This results in the formation of salts in the ash and reduces the NOx and SOx concentrations in the gas medium. The redox environment, conditioned by the presence of moisture, leads to the emergence of extra H and OH radicals. They can also interact with NOx and SOx in line with the reactions: 2 NO + 4H2 + O2 \(\rightarrow\) N2 + 4H2O (at a temperature above 200 \({}^{\circ}\)C); SO2 + 3H2 \(\rightarrow\) H2S + 2H2O (at temperatures above 1000 \({}^{\circ}\)C) [42]. The metal-containing components in the ash part of the dry biomass and FC can also interact with sulfur and nitrogen oxides (CaO + SO2 + 1/2O2 \(\rightarrow\) CaSO4; 3 SO2 + 2 Fe(OH)3\(\rightarrow\)Fe(SO3)3 + H2O; 2 Fe + 3 NO \(\rightarrow\) 3/2N2 + Fe2O3) at temperatures above 800 \({}^{\circ}\)C [44]. This results in the formation of new substances that either end up as ash residue or participate in further chemical reactions in the gas medium without forming NOx or SOx. The final content of NOx in flue gases is also affected by the type of nitrogen-containing compounds in the fuel. In biomass, most of the nitrogen is in volatile components that are released and burn out at the initial stage of ignition and combustion as compounds some of which do not produce nitrogen oxides [43]. As for coal and coal processing waste, nitrogen oxides are formed at the stage of the coke part oxidation at relatively high temperatures which are not achieved due to a decrease in temperature of fuel combustion when biomass is added [43]. Thus, it was experimentally established that adding extra components even with relatively low concentrations (10-30%) to fuel compositions based on fine coal processing waste or dust of low-grade coal significantly enhances the combustion of fuel pellets and reduces the concentrations of anthropogenic emissions in flue gases. The fundamental research findings provide a scientific evidence of the prospects of using multicomponent fuel pellets in real practice. They serve as a foundation for the development of an industrial technology of producing such fuel pellets, in particular for the calculation of the mass fraction of various components. The results offer the potential for the industrial recovery of abundant existing and annually produced coal processing (FC) and woodworking waste that poses a serious fire and environmental hazard if stored at open-air disposal sites. The cost of such waste-derived fuel is largely made up of transportation expenses and is much lower than that of high-quality fossil fuels. Moreover, the possibility of varying the component composition of fuel pellets by adding biomass or a highly reactive component will enable us to make more effective use of power-generating equipment. The operation of a hot-water boiler with grate firing of solid fuels can be optimized by enhancing combustion not only when employing an automatic control system, but also when changing the fuel composition to achieve the target indicators--for anthropogenic emissions (pellets with biomass) or power generation intensity (pellets with a highly reactive component).