Tuesday 30 October 2012

DISTILLATION

INTRODUCTION

                                        

                                      
                                        Distillation,  process involving the conversion of a liquid into vapour that is subsequently condensed back to liquid form. It is exemplified at its simplest when steam from a kettle becomes deposited as drops of distilled water on a cold surface.
                                        Distillation is used to separate liquids from nonvolatile solids, as in the separation of alcoholic liquors from fermented materials, or in the separation of two or more liquids having different boiling points, as in the separation of gasoline, kerosene, and lubricating oil from crude oil.
                                            Aristotle (384–322 bc) mentioned that pure water is made by the evaporation of seawater. Pliny the Elder (ad 23–79) described a primitive method of condensation in which the oil obtained by heating rosin is collected on wool placed in the upper part of an apparatus known as a still


DEFINITION


       Distillation is the technique of heating  a liquid to create vapour which is collected when cooled separate from the original liquid.

ADVANTAGES

  •      It is used to separate liquids from nonvolatile solids or solutes
Distillation is used to separate fresh water from a  salt solution and gasoline from petroleum.

Distillation is also used as a purification process in which non-volatile components are separated from volatile ones.

TYPES OF DISTILLATION

The simple distillation :-  

                                            Simple distillation is a procedure by which two liquids with different boiling points can be separated. It can be used effectively to separate liquids that have at least fifty degrees difference in their boiling points



The Fractional Distillation:- 
                                           When the substance with the lowest boiling point has been removed, the temperature can be raised and the distillation process repeated with the substance having the next lowest boiling point. The process of obtaining portions (or fractions) in this way is one type of fractional distillation



The Destructive Distillation :- 
                                           Another form of distillation involves heating out of free contact with air such substances as wood, coal, and oil shale and collecting separately the portions driven off; this is known as destructive distillation

Distillation apparatus diagram 


































USES






To separate a liquid and one or more other ingredients that are mixed together.

In industries that refine oil, desalinate water, create liquor, beer and wine,

To produce many chemical products used in homes and factories.

To get a pure substance (such as water from sea water)

To separate alcohol from water to make distilled spirits such as vodka,

To extract essential oils from plants