Staged combustion for NO/sub x/ reduction using high pressure air injection

The effects on emissions by applying high-pressure air injection on rotary kilns to achieve effective mixing and staged combustion are presented. A technique of using the energy of high-pressure air jets to achieve cross-sectional mixing in a tertiary combustion zone in rotary kilns resulting in reduced excess air requirement for optimum combustion is described. An additional result of the mixing method is the creation of a sub-stoichiometric secondary combustion zone that reduces the emission of nitrogen oxides.