Talk:Vapor–liquid equilibrium

Chembioeng Logo
Hi Henry I am currently working on a project to design a logo for petrochemical distillation company in South Africa They, strangely enough used the distillation diagram you have on this page as their logo. I have been researching into what other examples I can use as symbolisation. Symbols that carry the correct representation of the evaporation / condensation process, which are simplified. I have been searching for the symbol for condensation & the symbol for evaporation, but I cannot find any sort of symbol. (So I am assuming it doesn't exist?) Being in your industry, what other symbols may be related to the distillation industry or symbols related to the change of liquid - gas states generally in science. Or can you suggest where I can get the symbol for condensation & evaporation? Kindest regards Vanessa


 * Hi Vanessa,
 * Those circles in light blue with the jagged arrows through them are general heat exchanger symbols used by chemical engineers in chemical process flow diagrams. This logo is highly simplified miniversion of another diagram I made last year.  I will try to get back to you soon on this query soon, when I have a few moments to spare.  H Padleckas 19:43, 9 July 2007 (UTC)

Vapor Pressure as a function of Temperature
Henry, do you think it is really necessary to include more than a sentence or two stating that vapor pressures are a function of temperature and therefore partial pressures are also a function of temperature? All those equations using function of (T) as in P1(T) and P02(T) are very confusing and, at least to me, they are not needed. Just stating that vapor pressures are functions of temperature and, thus, so are partial pressures ought to be enough. Regards, mbeychok 04:32, 15 November 2006 (UTC)
 * Based on your recommendation, I took those equations out. Sorry it took a while, but I had "situations" in my personal life that demanded my attention and I was rather busy until now.  H Padleckas 22:52, 18 March 2007 (UTC)
 * Hello Henry, Milton told me you were writing on VLE, and then Dirk directed me here. Very thorough work indeed. As I have done a tiny bit of experimental work, some years ago, not too well documented, I know from the pages of Ind Eng Chem the pains to which experimenters would go in the determination of VLE, ensuring purity of components by several successive laboratory distillations discarding a good bit of the first and last fractions, correcting for changes of barometric pressures between tests etc. The design of the apparatus was different in the cases I read about, the two names that easily come to mind are those of Othmer and Gillespie. At the time of my interest in these a miniscule sample was taken from the gas and the liquid phases and analysed eg by refractive index measurements. The apparatus and the analytical technique must have developed pretty much during the years and I expect that new methods might be used now for vapour composition measurement without removal of any liquid?As you must know the apparatus used runs with total reflux, and the equilibrium concentrations would be similar to idealised continuous distillation concentrations, where corrections could be applied for change of conditions on successive trays. This has raised my interest in a sketch of such an equipment. I presume, that you would intend to present such drawing(s), and I would be interested seeing such.


 * I've read through, reasonably thoroughly, what you have written so far, and to me all seems to be understandable, there are only a couple of typographical errors (omissions?) in the penultimate paragraph, but I have not altered anything; you might wish to read through those lines. Otherwise all is well done. Kind regards, LouisBB 21:00, 6 December 2006 (UTC)

In the penultimate para starting with:... At a given Ptot ...... in the next line you wrote... function of x1 (or x1) and this ...... Did you not mean the bracketed item to be (or x2) ? Have a nice Christmas and New Year, Cheers LouisBB 20:51, 23 December 2006 (UTC)
 * Yes, it took me a while unfortunately but I made that correction. I finally put in the diagrams I wanted to put in.  I am now pretty much ready to move this "temp" article to Vapor liquid equilibrium.  H Padleckas 22:52, 18 March 2007 (UTC)
 * I've moved the "temp" page to the permanent article Vapor-Liquid Equilibrium with variations of the title redirecting to it. If somebody thinks the proper title should be Vapor-liquid equilibrium, you can move the page to it.  H Padleckas 02:05, 19 March 2007 (UTC)

Ternary diagram details
Someday I plan to take some of the ternary diagram details out of here and instead put in a link to a very similar version of this article in Engineering Wiki which will have this more detailed discussion, which I have yet to copy to Engineering Wiki. I think these details are too involved and complex for the general Wikipedia reader and the link will be there for those few who are truly interested. H Padleckas 01:41, 22 March 2007 (UTC)

The HTML equations were badly rendered with a number of errors
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Likewise, I could baldly claim that the entire article “was badly rendered with a number of errors”. Or, for example, that all Mbeychok’s edits are typographically illiterate such that they have to be “re-done entirely”. Incnis Mrsi (talk) 20:40, 13 February 2013 (UTC)


 * I had no intent to denigrate anyone and I apologise if you are offended. But the fact remains that the HTML equations had numerous formatting errors (not content errors). All one needs to do is print a copy of that section (as I did) before and after my revisions (as I also did) to see the extent of what was corrected. I am sure that, if you did that, you would see that I did not simply "baldly claim" anything. It took me about two hours to get the equations fixed and if I had to list and explain all of my fixes, it would have taken another two hours ... so I simply said they were "badly rendered with a number of errors". In hindsight, perhaps I should have made clear that the problem was in formatting ... not content.


 * Once again, if I have offended you, I apologise and it was no my intent to offend anyone. mbeychok (talk) 21:13, 13 February 2013 (UTC)
 * Do not waste the database room for excuses. Try to learn about &#123;{math}} the things I know. I will not experiment with vanilla texhtml appearance and will not compare it against your variant. Just show a screenshot: what exactly appeared so bad to you? Incnis Mrsi (talk) 21:27, 13 February 2013 (UTC)


 * I have already apologised if I offended you, but I don't intend to engage in further debate. As I said before, you can make prints of that section before and after my corrections to see where the formatting errors were corrected. You really must learn to curb your temper. mbeychok (talk) 22:09, 13 February 2013 (UTC)

@Incnis Mrsi: The version before that edit had indeed a couple of minor issues: I can see 4 surplus newlines and one missing one, creating funny indentation patterns, a surplus colon and a leading-space box. I didn't check who did that, but I'm quite sure it wasn't you. I can also see some kerning problems, but that of course might depend on browser and preferences.

@mbeychok: I don't think printing is a good way to compare the two versions, in particular not to suggest to another user to print the pages. The rendering might be different on his screen and different again when printing. If you see a problem which he doesn't, the best approach is to describe it or if necessary provide a screenshot, so the problem can be identified and avoided in the future. What I don't understand: if you think LaTeX would be better, why did you put all the effort in converting to HTML? &mdash;&thinsp; H HHIPPO  19:43, 14 February 2013 (UTC)


 * HHIPPO, thank you for your calm and polite comments ... I really appreciate them. If you will look at the history of this article, you will find that this article was created by H. Padleckas, a fellow chemical engineer and someone with whom I have often collaborated here and elsewhere. Since he originally chose to use HTML equations, I did not want to impose my thoughts about LaTex versus HTML on his work.


 * As for using printed pages or screen shots, I find it very much more simple and quicker to print pages than to make screen shots of them. In my opinion, making prints provides the same information as making screen shots. As I tried to explain to Incnis Mrsi, it would have taken me (a two-finger typist) another couple of hours to explain all of the fixes that I made ... there were a good many of them. So I suggested he make prints (which is what I did as my final check when I completed my work). I hope this clarifies the situation for you. Regards and thanks again. mbeychok (talk) 21:30, 14 February 2013 (UTC)


 * About changing from HTML to or math: that is certainly possible if you want, the original author doesn't own the article. Major changes should of course be announced on the talk page first, and the formatting should be kept consistent throughout the article (which btw. is not the case now).
 * About printing: there are many types of rendering problems which depend a lot on the local environment at the client side (browser, settings, available fonts, mediawiki preferences, skin, ...). In such cases, prints provide the same information as screen shots only if you make the prints, and then post them to Incnis Mrsi. What his browser doesn't show it won't print either. That's why a short description or a screen shot can be better. Btw: I used much less words above to describe a few layout problems I saw than you used to explain why you can't describe them. (I'm typing with 2–3 fingers myself ;-) &mdash;&thinsp; H HHIPPO  22:45, 14 February 2013 (UTC)


 * I'm sure you have heard the old saying that "the devil is in the details". I am guessing, but I think that I must have edited about 30-40 items or more in those equations. If I had tried to explain each of those edits (be they inserting thin spaces ... or changing the 0 and O superscripts to the smaller o superscript ... or changing the fraction slash to an ordinary slash ... etc., etc., it would easily have taken me another 2 hours or so. Be that as it may, thanks again for your comments. mbeychok (talk) 00:14, 15 February 2013 (UTC)