As in other countries in Central and West Asia, most of Kazakhstan's power plants have reached their potential as they were built mainly during the Soviet era. In this regard, it is important today to optimize coal consumption processes, introduce new environmentally friendly technologies and reduce emissions. And it is impossible without conducting detailed studies of the combustion of fuels in the combustion chambers of energy devices. It can provide complete information about the nature of complex processes of heat and mass transfer without special financial, time and labor costs. The existing models of the formation and destruction of nitrogen-containing substances NOx do not have a universal nature of use, since the fuel and combustion conditions are different. In this regard, the proposed work considered two models that are widely used. The aim of this work is to select a model that actually can describe the processes of dioxin formation in the combustion chamber of a real CHP boiler when high ash content coal is burned in it. The results of the simulation were verified with the data of field experiments, which allows an objective conclusion to be made. The obtained research data and the method of applying the selected optimal kinetic scheme of dioxin formation contribute to the development of new and optimization of existing measures to control environmental pollution

The paper describes the main features of the combustion of liquid fuel injections, developed a stochastic model for the atomization of liquid fuels injected into the combustion chamber at high pressures and high Reynolds numbers. A mathematical model for the combustion of liquid injections at high pressures and high Reynolds numbers is presented, which includes: the equations of continuity, motion, internal energy, the K-ε model of turbulence, a system of equations describing the processes of evaporation, mixing, rupture and coalescence of liquid fuel droplets. A stochastic model of atomization of liquid fuels injected into a combustion chamber at high pressures and high Reynolds numbers has been developed. On the basis of the proposed model, computational experiments were carried out to study the combustion of liquid fuel depending on the injected mass in the combustion chamber under given initial conditions in full. When studying the effect of the mass of liquid fuel on the processes of ignition and combustion at high pressures and high Reynolds numbers, the mass values for octane 6 mg and for dodecane 7 mg were taken as the most optimal. A further increase in the injection mass, both for octane and dodecane at optimal pressures, worsens the combustion process. The results obtained are of fundamental and practical importance and can be used to develop the theory of combustion of gaseous and liquid fuels.