System for coal injection in iron oxide reducing kilns

摘要

A method and means for improved control of the process for directly reducing materials containing iron oxides in a rotary kiln using a solid carbonaceous reducing agent, such as coal, introduced from the charge feed and discharge ends of the kiln, as the source of both fuel and reductant, and oxygen-containing gas introduced along the kiln length, is disclosed wherein the portion of the reducing agent fed at the discharge end is injected in the form of two or more streams through the discharge end of the kiln onto the charge bed in such manner as to permit close and efficient control of the process, particularly when carried out in larger kilns. The important features in creating and distributing the streams over the bed are described including their longitudinal distribution and axial spread, as well as their contact regions with the kiln interior side walls and the quadrants of the kiln barrel into which they are directed, to meet the incremental heat demands along the successive segments of the charge bed, whereby the bed and gas phase temperatures may be controlled and heat transfer to the bed enhanced.