Heat transfer and gas holdup studies in a bubble column: Air‐water‐sand system

Abstract

AbstractAir‐holdup and heat transfer coefficient data are reported for the air‐water and air‐water‐sand system as a function of air velocity in the temperature range 297‐343 K as measured in a 0.305 m diameter bubble column operating in semi‐batch mode and equipped with either a five‐ or seven‐tube bundle. A 65 μm average size sand powder is used at concentrations of 5 and 10 mass percent in the slurry. Available correlations of gas holdup and heat transfer coefficients are examined on the basis of these data. These are found inappropriate and inadequate for representing these experimental data. Gas holdup data are well represented by an approach based on Nicklin's (1962) work, and heat transfer data are adequately represented by a simple semi‐empirical expression. Accurate experimental data on additional systems are needed to develop a reliable heat transfer theory particularly for process representation at temperatures higher than ambient.