Nu/Sh Correlation for Particle-Liquid Heat and Mass Transfer Coefficients in Trickle Beds Based on Péclet Similarity

Abstract

Knowledge of the particle to liquid heat and mass transfer coefficients in trickle beds is important, particularly in contexts where exothermic reactions impede liquid replenishment over dried spots in the catalyst bed, or when the transport, especially in liquid-limited reactions, is curbed by excessive liquid–solid interfacial resistance. Although particle–liquid heat and mass transfer coefficients in trickle beds are linked to each other, the known Chilton–Colburn analogy or similar failed to yield a single Nu/Sh correlation to quantify both heat and mass transfer phenomena at the pellet scale. In this work, a single correlation embedding the heat and mass transfer information into a Peclet number was derived and validated over 1259 particle–liquid heat and mass transfer coefficients in trickle beds. Depending on whether a heat or a mass Peclet number was used, the proposed correlation predicted Nu and Sh numbers with average absolute relative errors of 18 and 22%, respectively. In particular, when equal heat and mass Peclet numbers occur, under physically and geometrically similar conditions, the correlation predicts true analogy between heat and mass transfer at the pellet level.