Flash distillation description

The idea of degrees of freedom in the design process can be further illustrated by considering a simple process unit, a flash distillation. (For a description of flash distillation see Volume 2, Chapter 11). 

In contrast to the description of distillation given earlier, which dealt with multistage distillation, flash distillation (Fig. 15) is carried out in a single stage. Liquid flows continuously through a heater, across a valve, and into a flash vessel. By heating the liquid and reducing its pressure across the valve, partial vaporization occurs in the flash... 

Several descriptions have been pubUshed of the continuous tar stills used in the CIS (9—11). These appear to be of the single-pass, atmospheric-pressure type, but are noteworthy in three respects the stills do not employ heat exchange and they incorporate a column having a bubble-cap fractionating section and a baffled enrichment section instead of the simple baffled-pitch flash chamber used in other designs. Both this column and the fractionation column, from which light oil and water overhead distillates, carboHc and naphthalene oil side streams, and a wash oil-base product are taken, are equipped with reboilers. 

An uncontrolled study in 2002 by Lucks examined the effects of 3-month dermal application of V. agnus-castus essential oil (oil distilled at some point in the shrubs development of the fruit but while some leaves were still on the plant) on menopausal and perimenopausal symptoms. A 1.5% solution of the essential oil was incorporated in a bland cream or lotion and applied once a day, 5 to 7 days/week, for 3 months. Descriptive outcome measures were self-report via a survey of symptomatic relief (major, moderate, mild, none, worse) and side effects. A total of 33% of women reported major improvement in symptoms, with the most often area of improvement being hot flashes/ night sweats. Both improvement and worsening occurred in the areas of emotions and menstruation flow. Subjects who were also on progesterone supplementation reported breakthrough bleeding (7). 

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