Influence of diffusive combustion on the rotary furnace performance

Diffuse combustion is one of the basic mode of the heat generation. Solution of the diffuse combustion problems very tightly connected with specific conditions of its utilization. Insufficient regarding of the specific conditions can significantly decrease their performance (in comparison by their technical possibility). On the other hand, by proper solutions of diffuse combustion, activity of thermal apparatuses can be significantly improved. Diffuse combustion can be realized by axial or radial burners. Axial diffuse burners are generating required flame length by adaptation of their geometry, mainly by the position and dimensioning of fuel nozzles. By their adequate arrangement combustion efficiency can be significantly improved. Radial diffuse burners consist in transversal fuel flow. By radial mixing, flame length in axial direction can be significantly decreased. Radial flame is arranged in such way that the principal combustion is executed in its primary part. This has important influence on development of combustion process. Pilot and industrial experiments of diffuse burners on the rotary furnaces enabled to achieve improved combustion and to increase the heat transfer directed to the heated material. The main contribution is very effective combustion of the secondary air, which results in the increasing influence of the secondary air proportion on the whole combustion process. Developed mathematical model of the rotary furnace combustion was used for burner design and flame optimal distribution in the burner side of the furnace. Presented diffusive burner was experimentally verified on the sintered magnesia production process in the rotary furnaces.