Mass Transfer in Beds of Modern, High-Efficiency Random Packings

Abstract

A new model has been developed for the prediction and correlation of mass-transfer rates in distillation columns containing random packings. Emphasis is placed on the characteristics of the newer “high-efficiency” random packings: IMTP, CMR, Fleximax, and Nutter. These packings are of the high void fraction, through-flow type and have become quite popular for new designs as well as for retrofits. In building the model use has been made of a large bank of experimental data from the laboratories of Fractionation Research, Inc., and the Separations Research Program (SRP) at The University of Texas at Austin. The model is based on an earlier SRP study of liquid holdup and gas pressure drop in beds of random or structured packing (Stichlmair et al. Gas Sep. Purif. 1989, 3, 19]. The only packing parameter needed is a “packing characteristic” which has a value of about 0.030 for a 2-in. Pall and Raschig rings and about 0.050 for the 2-in. nominal size of the high-efficiency packings listed above. The model was found to fit 95% of 326 experimental values of height equivalent to a theoretical plate (HETP) to within ±25% and all values within ±30%.

New mass‐transfer correlations for packed towers

“…(b) Performance data for IMTP 40 random packing in ethylbenzene/styrene service. 56 (c) Data of Wagner et al 43 for total reflux distillation of cyclohexane/n-heptane at 250 torr. (d) Data of Wang et al 55 for total reflux distillation of carbon tetrachloride/benzene at 760 torr.…”

Modeling the Water Scrubbing Process and Energy Requirements for CO2 Capture to Upgrade Biogas to Biomethane

“…Hottel et al 21 and Wang et al 9 list some of these for packed absorption columns. Equations suggested by Onda et al, 16 Billet and Schultes, 17 Wagner et al 18 and…”

HETP Evaluation of Structured and Randomic Packing Distillation Column

“…Wagner et al (1997), for example, developed a semi-empirical model, taking into account the effects of pressure drop and holdup in the column for the Nutter rings and IMTP, CMR and Flaximax packing. These packing have higher efficiency and therefore have become more popular for new projects of packed columns today.…”

“…(Furnas & Taylor, 1940;Robinson & Gilliand, 1950;Hands & Whitt, 1951;Murch, 1953;Ellis, 1953 andGarner, 1956). According to Wagner et al (1997), the HETP is widely used to characterize the ability of mass transfer in packed column. However, it is theoretically grounded in what concerns the mass transport between phases.…”