Abstract: A rotary kiln includes a novel air conveying system for delivering a supply of port air beneath the material bed of feed stock passing through the interior of the kiln. The air conveying system includes an air inlet port disposed in the shell of the kiln, a main air conveying channel which communicates with the air inlet port, and a plurality of air vent channels communicating with the main air conveying channel and the interior chamber of the kiln. The main air conveying channel is formed integrally in the refractory bricks which line the inner surface of the kiln shell and extends longitudinally and parallel to the rotary axis of the kiln. The air vent channels extend through the refractory bricks substantially radially with respect to the rotary axis of the kiln.

Abstract: An apparatus and method for feeding pulverized solid fuel to one or more burners of a kiln in which batches of the pulverized fuel are weighed and metered into air conduits at a rate controlled by the weight of the batch for the supply of an air-fuel mixture to the burners.

Abstract: A method and apparatus for drying coal in which the coal is dried by a hot gas and then quickly cooled with ambient air to reduce the oxidation rate and in which the air heated in the cooler is supplied to support the combustion that generates the hot gas. The drying gas exhausted from the dryer is utilized to extract coal product, to produce the fuel necessary to generate the hot drying gas and to provide a tempering gas to help maintain the combustor within a desired temperature range. Condensation of the exhaust drying gas is prevented by utilizing the hot gas discharged from the combustor, bypassing the dryer, and supplying it to the exhaust gas at a plurality of different points.