Rotary kilns: The relationship between controllable process variables and operational performance

摘要

Rotary kilns are common reactors in the mineral processing, metallurgical and chemical industries. Several thousand kilns are in service worldwide and new applications appear with regularity. Although often viewed as a mature technology, our understanding of this reactor is far from complete and kiln operators have chronic difficulties in relating actual or proposed changes in the process variables to kiln behaviour. In an attempt to improve on this situation, the paper first discusses kiln performance in terms of process fundamentals; i.e. heat and mass transfer, identifying both the strengths and weaknesses of this familiar reactor. Following on from this, and with the aid of a mathematical model, the influence of several controllable process variabes, for example fill, rotation rate, oxygen enrichment, free moisture in the solids feed, flame length, etc. in determining kiln performance is explored quantitatively.