Monday, August 3, 2009

Describe Simple Distillation

A chemist's distillation tower.


Simple distillation is a process that separates liquids by evaporating them, capturing the vapors at different points in their cooling cycles and letting them condense. It differs from fractional distillation, which combines greater precision in the temperature of the vapor and control of internal pressure in the collection columns to get much greater volume and precision in the outcomes. Simple distillation is still done by home enthusiasts to make perfume, liquor and soaps; fractional distillation is largely what runs an oil refinery.


History


Evidence of distillation processes have been dated back to roughly 500 B.C. on the Indian subcontinent, and roughly 100 B.C. in Ancient Greece. Some evidence of pots indicative of a simple distillation process have been unearthed in northern Iraq and Iran.


Earliest Uses


The likely earliest use of distillation was for the creation of either stronger alcoholic beverages or perfumes. The first large-scale distillery known to history was described in the fourth century A.D. in Greece, by Zosimos of Panopolis. The distillery in this case was used for making fortified wine. Distillation largely advanced in the Arabic-speaking parts of the world until the 12th century, when the techniques were introduced into Europe in Latin translations. By the 15th century, dedicated books on distillation were being published, and the process was being used for dye making and soaps.








Equipment


The basic process of a simple distillation system requires a heat source, a container for storing the material to be distilled, and tubes where the vapors can be captured, cooled down and condensates dropped down into collection pots. The alembic is an example of a simple distillation system, and its engineering descendants became the distillation pot and the common still. One of the first significant advances in distillation equipment was running water over the outside of the condensation vessel; this makes the condensation vessel much more efficient.








Features


Assume a mixture of water and alcohol, put to a boil. The alcohol has a lower boiling temperature than water does, but both will boil. Picture a funnel over the place where the boiling occurs, and the funnel feeding into a tube that runs in a lateral spiral off to the side. Both the alcohol and water will condense in the tube and collect in the bottom of each loop. The alcohol will condense sooner than the water will, so the condensates closer to the heat source will have a higher mixture of alcohol to water.


Uses


Simple condensation is also used to extract drinking water out of waste water, or salt water--the water will boil, be condensed and leave the salt (or other residue) behind. Simple distillation is used in industrial circumstances where you want to keep the liquid content of a chemical process, but throw out the solid wastes.

Tags: water will, alcohol water, condensation vessel, distillation process, distillation system