seminar 1 (dhaval prajapati)(10bpe078)

8/13/2019 Seminar 1 (Dhaval Prajapati)(10bpe078)

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DISTILLATION TYPES

DHAVAL PRAJAPATI

(10BPE078)


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19/8/2012 Distillation types 2

What is Unit Operation?

Unit operation is a something in which onlyphysical changes are takeing place.

What is Unit Process?Unit process is a something in which physical

changes are takeing place as well as chemicalchanges.


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What is distillation?

Distillation is a unit operation inwhich constituents of liquid mixture are

separated using thermal energy


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Distillation

Unit operation in which constituents of liquidmixture are separated using thermal energy Difference in vapor pressure at same temperature

is responsible The phases involved are vapor and liquid Vapor is always richer in the more volatile

component than liquid from which it is formed

Also known as fractionation Example: Separation of petroleum crude into

gasoline, kerosene, fuel oil, etc

19/8/2012 4Distillation types


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Types of Distillation

Simple Distillation Fractional Distillation

Steam Distillation Vacuum Distillation Flash Distillation Batch Distillation Continuous Distillation



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Simple Distillation



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Simple Distillation

Hot vapors produced are immediatelychanneled into a condenser that cools andcondenses the vapors.

The distillate will not be pure Distilled composition identical to that vapors

at the given temperature and pressure To separate liquids whose boiling points differ

greatly



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Fractional Distillation



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Fractional Distillation

Boiling points of the components in a mixture aresufficiently close Rectification is done i.e repeated vaporization-

condensation cycles within a packed fractionatingcolumn

As the solution to be purified is heated, its vapors riseto the fractionating column.

As it rises, it cools, condensing on the condenser wallsand the surfaces of the packing material.

Condensate continues to be heated by the rising hotvapors; it vaporizes again Each vaporization-condensation cycle will yield a purer

solution of the more volatile component.



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Steam Distillation



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Steam Distillation

Distil compounds which are heat-sensitive Temperature of the steam is easier to control than

surface of a heating element

Steam reduces the boiling point of the substanceto be distilled

Heat of steam will vaporize the distilled content

Vapor mixture is cooled and condensed, usuallyyielding a layer of oil and a layer of water



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Vacuum Distillation

For compounds having very high boiling points

it is better to lower the pressure instead ofincreasing the temperature for boiling

Once the pressure is lowered to the vapor pressure of the compound (at the giventemperature), boiling and the rest of thedistillation process can commence.



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Flash Distillation



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Flash Distillation Flash Distillation is simplest method of

distillation Also known as equilibrium distillation Carried out in a continuous manner

Feed stream is flashed into a chamber or flash drum and the liquid and vapor are allowed toseparate under equilibrium.

Feed is heated in a tubular heat exchanger

Hot liquid mixture is then fed to a separator via pressure reducing valve whereby pressure isreduced and vapor is formed.



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Batch Distillation Mixture is distilled to separate it into its

component fractions before the distillation stillis again charged with more mixture and the

process is repeated. The feedstock is added and the distillate drawn

off without interruption.

Batch distillation has always been an important part of the production of seasonal, or lowcapacity and high-purity chemicals



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Continuous Distillation Feed and products together containing the same amount

of total material, are continuously removed. Heat is added to the re-boiler and removed at the

condenser. The re-boiler vaporizes some of the liquid, which then

follows a treacherous path to the top of the column whereit is re-condensed.

Along the way most of the high boiling compounds will be left behind, and the distillate will be quite pure.

To further aid the separation process some of the liquiddistillate is often returned to the column where it flows

back to the bottom.



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Composition of the distillate and bottoms in batchdistillation changes over time

Continuous column operates under steady conditionswhere the composition at a given location does notchange over time.

This steady state operation is desired in almost allcontinuous unit operations.

Because the composition only depends upon the position inthe column

additional product streams can be easily tapped at differentheights and each tray will have a different composition ofcompounds.

Trays at the top of the column are rich in light boilingcompounds while those at the bottom are rich incompounds that only boil at high temperatures



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