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### Re: Liquid/Vapor phase diagram for ethanol/water solution

Posted: Sat Sep 21, 2019 12:40 pm
Hügelwilli wrote:
Thu Sep 19, 2019 1:46 am
For implementing the influence of pressure on the boiling temperature, we compared the common formulas like Antoine and Frost-Miller with data we found and decided for Frost-Miller. But we finetuned it, that it matches exactly 100°C at 0%abv and 78.17°C at azeotrope 97.18%abv at normal pressure, what are the most trustworth values we think.

The influence of the pressure on the difference between abv in the boiler and abv in the vapor we looked at measuement tables and tried to draw a line between the points. From the line we took values and feed our calculator with it. Not very scientific, but it doesn't need to be exact, because the influence of pressure on the abv difference is very small compared to the influence on the temperature. At 800hPa (2000 meters above sea level perhaps) the azeotrope is 97.39%abv according to our calculator. Not much difference to 97.18. But it boils at 72.3°C instead of 78.17. This is an important difference.
You are doing very good work. My hat is off to you, hefezelle, and the other members of your community who've contributed.
Hügelwilli wrote:
Sat Sep 21, 2019 6:27 am
Because of that it's one of our future plans to make a html for producing tables and diagramms automatically.
Something like you type in your pressure and your rectification and you'll get within a second a downloadable and printable diagramm with the curve of the wash, the curve of the vapor above the wash and the curve of the vapor after rectifcation.
Or you type in the pressure and you'll get a downloadable and printable table with perhaps 50 temperature values and the corresponding abvs in the vapor.
This is what I've been working on, though feeling a bit amatuerish lately. Perhaps include abv remaining in the boiler as well?