1,2PG/EG 10 200  Pall ring 63。5 124。8 142。2 106。7 96。58

EB/SM 100 31=200  Pall ring 63。5 126。2 142。2 55。9 73。78

EB/SM 100 11=200  Pall ring 58。4 46。8 43。2 45。8 40–488

EB/SM 100 5=800  Pall ring 40。6 31。2 19 33 28–388

p/o-Xylene 50 5=800  Pall ring 40。6 40。3 17。1 33 35–388

i-C4/n-C4 8533 200  Pall ring 16。5 51。5 53。3 48。3 519

i-Octane/tol 760 100  Pall ring 24。6 35 21。3 39。9 40。68

i-Octane/tol 760 200  Pall ring 33 60。1 49。5 50 66–718

D2O/H2O 350 HY-PAK #1 64。8 29。9 30。5 34。8 48。28

In all cases the countercurrent flow model was used。 All experiments at total reflux。 HETPs are reported in cm。 PG, propylene glycol; EG, ethylene glycol; EB, ethylbenzene; SM,    styrene。

specifically related to the need for more accurate mass-trans- fer correlations in packed columns and the use of these types of correlations in rate-based  simulation。

We begin by reviewing the performance of  a  few  of  the more commonly used packed-column mass-transfer correlations when they are used to predict the Height Equivalent to a Theoretical Plate (HETP) for binary separations。 The HETP function for binary systems is particularly important to the development of packing mass-transfer correlations  because  it ties the separation  performance  of a tower  expressed  in terms of equilibrium stages  to  that  column’s  performance expressed in terms of a rate-based differential contactor。 In particular, we focus on several packed-column mass-transfer/interfacial-area correlations found in commercially available column simulation software like Aspen Technology’s Aspen Rate  Based Distilla- tion component2: the  equations  of  Onda  et  al。,3  Bravo  and Fair4 (hereafter referred to as BF82), and Billet and Schultes5 for random packings,  the  correlation  of  Bravo,  Rocha, and Fair6 for wire gauze structured packings (hereafter referred to as BRF85), and the correlations of Bravo, Rocha, and Fair7 (hereafter referred to as BRF92) and of Billet and Schultes5 for sheet metal structured packings。  Table  1 is such  a comparison for binary distillation experiments with random packings。8,9 For each experimental system, we have calculated HETPs using the mass-transfer correlations for random packings  listed above。 As most distillations are primarily  vapor  phase  controlled, the results in the table can be considered tests of the robust- ness  of  each  correlation’s  kyam   predictions  (we  expect  KOy