Hexane and water are only partially miscible, whereas acetone is soluble in both. Are you looking for vapor-liquid (VLE) or liquid-liquid (LLE) or vapor-liquid-liquid (VLLE) equilibrium data? If no data exists, you may have no option but to estimate the equilibrium from UNIFAC.
Be careful...
To: MortenA
Yes, sir. I believe that 95+ % of the work required to be done by most chemical/petroleum engineers can be accomplished in any one of the major commercial simulators. However, some of the major issues confronting the average user are:
(1) Robustness, reliability, and execution...
Hi, Dick:
Glad you're active in eng-tips. I think the other forum mentioned by Morten relates to specific products, rather than generic issues in process simulation. I am sure you would be the best qualified moderator for such a forum, given your experience and proven track record. Your PD+...
The best answer is to select an exchanger type and look up the proper step-by-step computational method in:
(1) The old classic by Kern, "Process Heat Transfer" (McGraw-Hill, 1950), or
(2) The new classic by Hewitt, Shires and Bott, "Process Heat Transfer" (CRC Press, 1994)...
For a given solute in a given solvent, Henry's constants are generally a strong function of temperature and also a function of concentration. The liquid phase is not required to be boiling (i.e., stripping from a cold solution is feasible and the Henry's constants for the solutes still apply...
I would recommend studying "Molecular Thermodynamics of Fluid Phase Equilibria" by Prausnitz, Lichtenthaler and Azevedo (Prentice-Hall, 1999). The relevant Section is 10.4, starting at Page 596.
Prausnitz et al also have an excellent discussion regarding estimation of gas solubility...
The best source for computing liquid compressibilities in hydrocarbon systems is the API Technical Data Book, Petroleum Refining (published by the American Petroleum Institute). This is available in most technical libraries.
By the way, the liquid compressibility is NOT the thermal expansion...
The original question discussed conduction only, and others have pointed out the need to consider convection also. As pointed out by corus, if the difference in plate temperatures is great, radiant heat transfer will also become important.
The Hewitt et. al. reference I cited also discusses...
The biggest source of inaccuracy results from errors in estimating:
(1) k (i.e., Cp/Cv ratio), and
(2) z, the gas compressibility factor, used in the gas density calculation.
For a real gas, both need to be found using a respectable equation of state, such as Lee-Kesler or Peng-Robinson.
NOTE...
I do not generally trust the default interaction coefficients in commercial simulators, as you don't know the basis on which they were developed. In my opinion, the best procedure is as follows:
(1) Collect ALL of the liquid-liquid equilibrium data for toluene-water (e.g., from the DECHEMA...
This problem cannot be solved properly without use of a full-fledged chemical process simulator, such as Hysys, PRO II, Aspen Plus, Chemcad, or PD Plus. Do you need to demethanize the gas? If so, there are innumerable tradeoffs between capital expenditure v/s operating cost for the...
I recommend consulting the authoritative book "Process Heat Transfer" by G.F. Hewitt, G.L. Shires, and T.R. Bott (CRC Press, 1994). This is considered to be the definitive update to Kern's classic text of the same name. Natural convection correlations are discussed in Section 2.4.0...
The best way to find these parameters is to go to the multi-volume DECHEMA data books (available at all major chemical enginering libraries). This is a huge compilation of the world's published VLE data. For each binary VLE pair, the vapor pressure constants are provided. Then, the dataset is...
Re. June 21, 2003 comment by 25362.
Hi:
I have very much enjoyed this set of exchanges and appreciate the issues brought out in prior communications. I'm sure you know by now that I do a lot of thermodynamic work to make a living and my views are, perhaps, a bit skewed in favor of rigorous...
ladyCR:
The best solution is to buy an inexpensive ($2,000 one-time fee for an outright purchase) but extremely competent process simulator called PD-Plus from Deerhaven Technical Software (Burlington, MA).
Generally, I would not recommend use of shortcut methods for such work. If you have a...
