Distillation columns with a high-purity product (down to 7 ppm) have been studied. A steady state model is developed using a commercial process simulator. The model is validated against industrial data. Based on the model, three major optimal operational changes are identified. These are, lowering the location of the feed & side draw streams, increasing the pressure at the top of the distillati...

The positron lifetime measurements have been performed as a function of temperature for liquid methane and propane and as a function of magnetic field for liquid argon. The long o-Ps lifetime, high o-Ps intensity, and a strong temperature dependence of these values are observed, and interpreted as being due to the Ps localization in the bubble state. The bubble size and surface tension are eval...

A mc thod is described for producing sulfur thaL conLains Ie. Lhan 1.3 X lO5 m ole [racLion of li q uid-solu ble, solid-insolubl e impuriLies as dcLermin ed by Lh e fr'eezing point depression . This corr e ponds t.o a purity of 99.999 mole p ercen t . Man y of Lhe impurities, including organic maLLcl', a r(' re moved by o,(ldaLion with s ulfuric and nitric ac ids. The nonvo lati le impuri ties ...