Page 243 - Separation process engineering

Table 5-A1. VBA program for ternary distillation with constant relative volatility starting at top of

column

Option Explicit
Sub Ternary_top_down()
' Ternary distillation with constant alpha. Frac recoveries of LK
and HK given.
' There is a LNK present and its frac rec in distillate is
guessed.
Sheets("Sheet1").Select
Range("A13", "G120").Clear
' Declare variables
Dim i, j, feedstage, N As Integer
Dim alphaAB, alphaBB, alphaCB, F, fracBdist, fracCbot, q, LoverD,

LoverV As Double
Dim LbaroverVbar, D, B, L, V, Lbar, Vbar, Eqsum, fracAdist As
Double
Dim xA, xB, xC, yA, yB, yC, zA, zB, zC, xAbot, xBbot, xCbot As
Double
Dim DxA, DxB, DxC, BxA, BxB, BxC, xAdist, xBdist, xCdist As
Double
Dim fracAdistcalc, difference, epsilon, df, watch As Double
Dim xAold, xBold, xCold, frac, xAcalc, xBcalc, xCcalc As Double
'Input data from spreadsheet
alphaAB = Cells(3, 2).Value
alphaBB = Cells(3, 4).Value
alphaCB = Cells(3, 6).Value
feedstage = Cells(3, 8).Value
F = Cells(5, 2).Value