Evolution of Nusselt Correlation for Recovery of Waste Heat from Industry Flue Gases using Quarry Dust and Iron Ore Particles

Process industries usually release significant temperature exit gases because of induced high energy inputs that are probably treated as secondary energy sources. Extensive saving in net energy demand is achievable only by retracing such waste heat. The purpose of the paper is to explain an empirical analysis of the interaction between solids and heated gas inside a vertical duct, which recovers the heat contained in the gas. Information related to the heat exchange sequences are noted since very little data are accessible in articles in this regard. Based on the findings, it is proposed a model for the Nusselt number (heat transfer coefficient): Nu=0.03875(ReP)0.8274(Pr)0.4157. During the research, a cyclone and riser system used in the cement industry for many years was built to model the working of a suspension preheater. However, the research results may also apply to other industries where waste can recover heat. © 2022, The Institution of Engineers (India).