New model for prediction of tray efficiency in cross flow sieve trays

Abstract

A new simplified model for predicting mass transfer efficiency on a commercial scale sieve tray has been developed. The model is based on the analysis of tray hydrodynamics on a cross flow sieve tray. It considers the froth as a combination of small and large bubbles as well as gas jets. The small bubbles are considered to reach saturation in froth and thus have the efficiency of 100%. The model estimates the average efficiency of large bubbles as 40% and that of jets as 70%. The model requires estimation of only two parameters, namely, fraction of small bubble (FsB), fraction of jetting (FJ), and is applicable to both froth and spray regime. The model has been confirmed by a large and diverse databasc. The model is applicablc within pressure range1.3-2758 kPa, liquid density rangc.380-949 kg/ml , gas density range 380-949 kg/ml• liquid viscosity range 0.05-1.56 mPa.s, gas viscosity range 0.007-0.013 mPa.s. and surface tension range 0 I-55 mN/m. The prediction is found to be within:!: 25%. According to the model tray efficiency (Boo) is calculated by following equation.