The features of the formation of convective flows arising in three-component gas mixtures in the presence of special diffusion mixing regimes are investigated. The time variation of the isoconcentration lines of the heavy component of the mixture and the average kinetic energy are consideredas characteristics of convective flows. A numerical model based on the splitting scheme in physical parameters is used to calculate the characteristics of convective flows arising in a vertical cylindrical channel. It is shown that nonmonotonic distributions of component concentrations and kinetic energy can occur in ternary gas mixtures, where special diffusion regimes are manifested. The time of stability loss of the mechanical equilibrium of the mixture and the time of developed convective flows are determined.