Patent ID: 6672865
Filing Date: 2004-01-06
Classification: F27B,F27D

Abstract:
A method of mixing a high temperature kiln gas stream in a rotary vessel of a mineral processing kiln, said vessel having a cylindrical wall, a combustion air inlet/burner end and a kiln gas exit end, said gas kiln stream having multiple gaseous components consisting essentially of the products of combustion of fuel burned in an oxygen-containing gas comprising combustion air, unburned fuel and the oxygen-containing gas, said method effective to reduce the emission of gaseous pollutants from the kiln and comprising the step of injecting air into the gas stream through an air injection tube terminating in an injection port spaced apart from the vessel wall and the axis of rotation, said air being injected at a mass flow rate of about 1 to about 15% of the mass rate of use of combustion air by the kiln and at an energy input level of at about 1 to about 10 Watt-hour per pound of injected gas, and directed into the kiln gas stream to impart rotational momentum to the kiln gas stream in the vessel at a point along the length of the rotary vessel where the kiln gas temperature is greater than 1800Â° F.