What is the best text book resource (or comprehensive publications, etc) on multi component distillation? particularly the separation of nobel gases from air. Air has all of the nobel gases (except maybe krypton) but they are trace so finding the off takes for these would be incredibly difficult and the off take trays would have only trickles of liquid on them compared to the O2 and N2 trays. Or do they even use tray distillation for pulling nobel gases out of air? I would be interested in the VERY detailed calculations of numerous component distillation even if the text goes back to statistical thermodynamics (which I suspect it will have to in order to go beyond macabe tieli and tertiary diagrams). This would also apply to fractionation of oil as well, though oil is a more even spread than nobel gases.