One of the promising ways to comprehensively solve the problems of ecology and sustainable energy is the production of energy from household and industrial waste by obtaining and then burning an intermediate target product - gas fuel (synthesis gas or biogas). The most effective way to intensify the combustion process is to swirl the air-fuel flow. The paper proposes a mathematical model of the turbulent combustion process, which takes into account the swirl of the flow. The use of mathematical modeling and numerical research methods makes it possible to study, in a conjugate formulation, the processes of gas dynamics, heat and mass transfer, and detailed chemical kinetics in a swirling reacting jet with high accuracy. A model of a combustion chamber with one combined burner is presented. Target. The work is a study of the modes of combustion of gaseous fuels with a minimum emission of pollutants in relation to the energy sector on the example of a gas burner GMU-45 of a power boiler TGME-464. a method of mathematical modeling is proposed, which makes it possible to estimate with high accuracy the efficiency of low-emission combustion, including heat and mass transfer processes and chemical kinetics for swirling flows. A numerical study of the turbulent gas flow during the co-combustion of natural gas and synthesis gas was carried out using the Simcenter STAR-CCM+ program. It has been established that for the co-combustion of biogas, the optimal air coefficient α = 1.09 for the minimum emission of CO₂ and CO.