I have to calculate the number of evaporated molecules of volatile liquids (acetone, ethanol, formaldehyde, liquid ammonia) at room temperature or any elevated higher temperature. For given liquid volume, what is equivalent its vapor volume. Basically, I want to find ppm level of volatile liquids in a test chamber of some fixed volume. If I put some liquid amount of few microliters inside testing chamber (e.g. 250 ml) at room temperature and pressure then with the time how can I calculate vapor ppm level of that liquid. Please give me formula or relation to find out. Thank you
You can do a simple flash calculation with a simulator like Hysys (Yokogawa/KBC, Honeywell, and AspenTech all offer this product),
If you don't have access to a simulation to perfor the flash; you can easily perform the flash calc by hand with the assumption Ki = VPi/P for each component and an iterative calculation to converge on fraction vapor. I can give you a simple flash spreadsheet you can adapt for your components if you need it.
Hi
If understood well, all you need is to know the saturated vapor pressure of each component..Of course, for very small amounts you may find that saturating the test chamber with a given component requires more liquid amount than what you put in, so that everything evaporates and then, Px= nxRT/Vc with nx the number of mols you put in and Vc the chamber volume...
From published vapor pressure data you can get the difference in volumes vapor and liquid from the complete Clayperon equation which is rigorous. Then all you need is the liquid density which is published.
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