METHOD AND INSTALLATION FOR SPRAYING AND CALCINATION OF PULVERULENT MATERIALS

摘要

The powder feed to a rotary calcining kiln is distributed in the combustion air feed to the furnace in a cyclonic device. The powder is fed into the device via a branch. Hot combustion air is fed in from the fluidised bed prod. cooler on the furnace which acts as a recuperator. A side stream from this is passed through a cyclonic separator and its pressure raised in a fan. It is then injected via a branch at a higher velocity than the main air stream. Fresh air can be used for this. The kinetic energy in this stream is greater than that needed to effect dispersion of the powder. Used in e.g. cement prodn., the injected air stream the powder supply and its distribution can vary (a) if dust collects in the metering valve into the furnace, (b) if resistance in the valve increases due to changes in the furnace conditions, (c) of the air supply is altered due to abnormal operations, and (d) if the resistance of the air line increases due to dust collecting in it. This process overcomes these problems, since the dispersion is done by the jet of air.