Excel library for process calc's including distillation

[dbert]

yes, with PRSV I mean the Stryjek and Vera extension of Peng Robinson, I would be interested in comparing results agaisnt the three parameters TWU included in Properties ans simulators as PRO II, Orbey and Sandler in their book modeling vapor liquid equilibria chapt. 3.1 suggest TWU for mixtures that contain fluids in supercritical state, this is common with natural gas, however I presume that three parameters could provide a better fitting of vapor pressure and density.

[mderra]

dbert,
I did some tests for natural gas mixtures, when calculating phase envelopes for streams containing C1, C3... and heavy components (C10 and higher) with Twu (Properties) and PRSV (Aspen) TWU shows better results, email me a message for additional information

[mpat]

mderra,
working mainly with natural gas I use the base SRK API exstension (Graboski & Daubert ) which works well but I am curious to evaluate the features of extended correlation, could you email to maurice.patton@gmail.com ?
Thank you.

[rense]

I wish to evaluate ethanol n-heptane equilibria at 15 BAR, can you share some VLE data points ?

[carlo.stenali]

Rense, I have BIPs for PR-NRTL Wong Sandler Mixing rules, extended alpha function , BIPs are from Properties database

K12 0.134808
A12 1528.91
A21 2047.97
G12 0.336973

I attach
TXY diagrams at 2 Bar and 15 Bar
PXY diagram at 333 K
you can compare PXY at 333 K with that included in Modeling Vapor Liquid Equilibria (Orbey and Sandler)

[carlo.stenali]

I attach PXY for ethanol n-heptane at 333 K , you may compare with that included in Modeling Vapor Liquid Equilibria by Orbey and Sandler

[rense]

thanks Carlo,
the PXY diagram shows well the phase equilibria behavior of ethanol heptane at low pressures, however the predicted phase equilibria @ 15 Bar (the condition which interest me) seems more regular.

[mderra]

I am modeling water-ammonia system, do you have suggestions for fugacity and enthalpy models ?
Operating conditions 18 Bar

[carlo.stenali]

mderra,
my copy of Prode Properties does include several BIPs for water ammonia (see image), I attach a few values

WILSON 158.447 -1227.49
NRTL -2191.2 1305.86 0.105957
UNIQUAC -1009.48 -291.765
SRK -0.283201
PR -0.268977
PR-NTRL-WS -0.10489 -6801.87 6754.34 0.0258625
PR-WILSON-WS -0.873655 1580.5 -1484.45
PR-UNIQUAC-WS 0.0700976 -1363.7 -513.344

perhaps accepting some errors you can adopt PR, SRK with standard mixing rules for enthalpy, fugacity at 18 Bar (however complex mixing rules are available)

[mderra]

thanks,
I have found PR (with extended alpha and kij -0.268977) reasonably good for this binary.

[Almart]

I am simulating a distillation column (30 trays, feed at tray 14, reboiler, total condenser) with Prode,
can I specify a flow rate for a component at bottom ?

[dbert]

Almart,
I have utilized the application example column.xls distributed with Prode Properties, it allows to specify component's flow rates and fractions at top and bottom of the column.
There are cells where you define the specification's type (reflux ratio, ratio top to (total) feed, bottom to (total) feed, component's fraction in product and component's fraction at bottom).
Perhaps you can provide some additional details on the specific problem.