Distillation Columns Containing Structured Packings:  A Comprehensive Model for Their Performance. 2. Mass-Transfer Model

Abstract

This is the second part of a two-part paper dealing with the fluid mechanics and mass transfer in structured packings for distillation column service. The first part elucidated pressure drop, flooding, and liquid holdup. The second part covers the generation of effective interfacial area and provides a general correlation for predicting the mass-transfer efficiency as a function of surface type, packing geometry, phase flow conditions, and fluid properties. The mass-transfer model has been tested against a variety of commercial structured packings, for distillation pressures ranging from 0.33 to 20.4 bar. In all cases the fit of the data is excellent, with the possible exception of the highest pressures, where additional factors of axial mixing appear to have an effect.

Pilot-scale validation of Enzymatic Reactive Distillation for butyl butyrate production

“…The mass transfer and hold-up correlations are taken from literature [29][30][31]. For the coated packing a new value for the specific surface area was determined within this work.…”

Dynamic simulation and analysis of a pilot-scale CO2 post-combustion capture unit using piperazine and MEA

“…The partial differential equations (PDE) describing the spatial and temporal variation of state variables are coupled with algebraic equations for mass and hydraulic properties (Rocha et al 1993(Rocha et al , 1996, mass and heat transfer fluxes, and the extended UNIQUAC thermodynamic model (Thomsen & Rasmussen, 1999). The PDEs are discretized in the axial domain using the finite differences method.…”

HETP Evaluation of Structured and Randomic Packing Distillation Column

“…Shi and Mersmann's (1985) correlation for sheet metal structured packings can be written: It must be pointed out that the authors have not checked the correlation with fluids with different densities and viscosities. Later on, Rocha et al ( , 1996) developed a mechanistic model aiming the design and optimization of CSSP (continuous separation structured packing) distillation columns of the metallic corrugated type, also applied to absorption and stripping processes. Liquid holdup prediction was the key to the development of correlations to measure pressure drop, capacity and mass transfer efficiency in the packing.…”

“…Those correlations involved parameters related to surface treatment, as contact angle on the packing surface, as well as packing geometry, liquid and vapor flow rates and physical properties of the system . For the estimation of the liquid side mass transfer coefficient, Rocha et al (1996) used a correlation developed by Brunazzi and coworkers (1995) for the evaluation of effective areas in absorption columns containing Mellapak 250Y and Sulzer BX. studied correlations to calculate flooding velocity and mass transfer efficiency by using the concept of HETP for distillation columns filled with structured packings.…”

“…Orlando Jr. et al (2009) made several tests with a hydrocarbon mixture (C 8 -C 14 ) to evaluate HETP using six HETP correlations to find out which is the most appropriate for structured packed columns with medium distillates. The theoretical models investigated are: Bravo et al (1985), Rocha et al ( , 1996, Brunazzi and Pagliant (1997), Carlo et al (2006) and Olujic et al (2004). As the laboratory distillation column was operated continuously, different HETP values were found by the models for each section of the column.…”