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producing 99.5%pure glycerine

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April 20, 2017, 10:19 PM
sanddy
producing 99.5%pure glycerine
does anyone know how or where to buy a glycerine distiller to produce pharmaceutical grade glycerine?
April 26, 2017, 02:27 PM
WesleyB
To distill pure glycerine you need to do it under as high a vacuum as you can economically manage. 10 millimeters of atmospheric pressure would be good. My vacuum pumps pull 100 millimeters and something like 1/4th atmospheric pressure (760 millimeters at sea level). Glycerine boils at a high temperature, without looking it up it is about 300 degrees celcius which is pretty hot. But if you reduce the air pressure inside the still it boils at a much lower temperature, without looking it up, maybe 150 degrees centigrade. Operating a vacuum still is more complicated than running a regular still. For example in using boiling chips to form a center for vapor/gassification, you have to put in new boiling chips every time the gas pressure elevates from lowest vacuum. When the pressure rises the liquid pushes itself into the boilng chips so there is no seed gas inside the rock/chip for the vapor /gas to form on in the boiling, then bumping will ocuur (bad). A vacuum still pot and receiving flask has to have thick enough walls or it will implode from high vacuum. Kimble Kontes sells glassware suitable to make vacuum stills with. Kontes at the Custom Glass Shop will make anything you want if it's not in their large catalogue. Also Kimble Kontes changed their name a few years ago to Chase Kontes or something like that. They also sell vacuum pumps that may be resistant to internal corrosion due to strong chemicals passing through the vacuum pump as a gas.
June 18, 2017, 04:21 PM
sanddy
Thanks for that. Very informative!