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DistillationFrom Wikipedia, the free encyclopedia

"Distiller" and "Distillery" redirect here. For other uses, seeDistiller (disambiguation)and Distillery

(disambiguation).For other uses, seeDistillation (disambiguation).

Laboratory display of distillation: 1:A source of heat 2:Still pot 3:Still head 4:Thermometer/Boiling point

temperature5:Condenser 6:Cooling water in 7:Cooling water out 8:Distillate/receiving flas 9:!acuum/gas inlet 10:Still

receiver 11:"eat control 12:Stirrer speed control 13:Stirrer/heat plate 14:"eating #$il/sand% bath 15:Stirring means e&g&

#shown%' boiling chipsor mechanical stirrer 16:Cooling bath&()*

Distillationis a process of separatingcomponent substances from li+uid mi,turesthrough

vaporisation and condensation' based on different volatility#vapori-ationpoint% of components in the

mi,ture& Distillation is a unit operation'or a physical separation process' and not achemical reaction&

Commercially' distillation has a number of applications& .t is used to separate crude oilinto more

fractions for specific uses such as transport'power generationand heating& Air is distilled to separate

its componentsnotably o,ygen'nitrogen' and argonforindustrial use&Li+uid chemicals for diverse

uses are distilled after synthesisto remove impurities and unreacted starting materials& Distillation

offermentedsolutionscan producedistilled beverageswith a higher alcohol content& The premises

where distillation is carried out' especially distillation of alcohol' are nown as adistillery&Astillis the

e+uipment used for distillation&

Contents

(hide*

) "istory

0 Applications of distillation
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the uan dynasty&(3*Arabs learned the process from the Ale,andrians and used it e,tensively in

their chemical e,periments&(citation needed*

Clear evidence of the distillation of alcohol comes from theSchool of Salernoin the )0th century&(0*

(5* 4ractional distillation was developed byTadeo Alderottiin the )1th century&(7*

.n )5>>' 2erman alchemist "ieronymus Braunschweigpublished Liber de arte destillandi#The Boo of

the Art of Distillation%(8*the first boo solely dedicated to the subEect of distillation' followed in )5)0 by a

much e,panded version& .n )75)' ohn 4renchpublished The Art of Distillationthe first maEor @nglish

compendium of practice' though it has been claimed(*that much of it derives from BraunschweigFs

wor& This includes diagrams with people in them showing the industrial rather than bench scale of the

operation&

"ieronymus BrunschwigFs Liber de arte Distillandi de Compositis#Strassburg' )5)0% Chemical "eritage 4oundation

A retort
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Distillation

$ld Grainian voda still

Simple li+ueur distillation in @ast Timor

As alchemyevolved into the science ofchemistry' vessels called retortsbecame used for distillations&

Bothalembicsand retorts are forms of glasswarewith long necs pointing to the side at a downward

angle which acted as air6cooled condensersto condensethe distillate and let it drip downward for

collection& Later' copper alembics were invented& ?iveted Eoints were often ept tight by using various

mi,tures' for instance a dough made of rye flour& (=*These alembics often featured a cooling system

around the bea' using cold water for instance' which made the condensation of alcohol more efficient&

These were called pot stills& Today' the retorts and pot stills have been largely supplanted by more

efficient distillation methods in most industrial processes& "owever' the pot still is still widely used for

the elaboration of some fine alcohols such as cognac'Scotch whisy'te+uilaand somevodas&;ot

stills made of various materials #wood' clay' stainless steel% are also used by bootleggersin various

countries& Small pot stills are also sold for the domestic production()>*of flower water oressential oils&

@arly forms of distillation were batch processes using one vapori-ation and one condensation& ;urity

was improved by further distillation of the condensate& 2reater volumes were processed by simply

repeating the distillation& Chemists were reported to carry out as many as 5>> to 7>> distillations in

order to obtain a pure compound&())*
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.n the early )=th century the basics of modern techni+ues including pre6heating andreflu,were

developed' particularly by the 4rench'())*then in )1> a British ;atentwas issued toAeneas Coffeyfor

a whisey distillation column'()0*which wored continuously and may be regarded as the archetypeof

modern petrochemical units& .n )88' @rnest Solvaywas granted a G&S& ;atent for a tray column

forammoniadistillation()1*and the same and subse+uent years saw developments of this theme for oil

and spirits&

Hith the emergence ofchemical engineeringas a discipline at the end of the )=th century' scientific

rather than empirical methods could be applied& The developingpetroleumindustry in the early 0>th

century provided the impetus for the development of accurate design methods such as the


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?aoultFs law states that the vapor pressure of a solution is dependent on )% the vapor pressure of each

chemical component in the solution and 0% the fraction of solution each component maes up aa

the mole fraction&This law applies toideal solutions' or solutions that have different components but

whose molecular interactions are the same as or very similar to pure solutions&

DaltonFs law states that the total vapor pressure is the sum of the vapor pressures of each individualcomponent in the mi,ture& Hhen a multi6component li+uid is heated' the vapor pressure of each

component will rise' thus causing the total vapor pressure to rise& Hhen the total vapor pressure

reaches the pressure surrounding the li+uid' boilingoccurs and li+uid turns to gas throughout the bul

of the li+uid& Iote that a mi,ture with a given composition has one boiling point at a given pressure'

when the components are mutually soluble&

An implication of one boiling point is that lighter components never cleanly Jboil firstJ& At boiling point'

all volatile components boil' but for a component' its percentage in the vapor is the same as its

percentage of the total vapor pressure& Lighter components have a higher partial pressure and thus

are concentrated in the vapor' but heavier volatile components also have a #smaller% partial pressure

and necessarily evaporate also' albeit being less concentrated in the vapor& .ndeed' batch distillation

and fractionation succeed by varying the composition of the mi,ture& .n batch distillation' the batch

evaporates' which changes its compositionK in fractionation' li+uid higher in the fractionation column

contains more lights and boils at lower temperatures&

The ideali-ed model is accurate in the case of chemically similar li+uids' such as ben-eneand toluene&

.n other cases' severe deviations from ?aoultFs law and DaltonFs law are observed' most famously in

the mi,ture of ethanol and water& These compounds' when heated together' form ana-eotrope' which

is a composition with a boiling point higher or lower than the boiling point of each separate li+uid&

!irtually all li+uids' when mi,ed and heated' will display a-eotropic behaviour& Although there

arecomputational methodsthat can be used to estimate the behavior of a mi,ture of arbitrary

components' the only way to obtain accurate vaporli+uid e+uilibriumdata is by measurement&

.t is not possible to completelypurify a mi,ture of components by distillation' as this would re+uire

each component in the mi,ture to have a -eropartial pressure&.f ultra6pure products are the goal' then

further chemical separationmust be applied& Hhen a binary mi,ture is evaporated and the other

component' e&g& a salt' has -ero partial pressure for practical purposes' the process is simpler and is

calledevaporationin engineering&

Batch distillation[edit]

ain article: !atch distillation

A batch still showing the separation of A and B&
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"eating an ideal mi,ture of two volatile substances A and B #with A having the higher volatility' or

lower boiling point% in a batch distillation setup #such as in an apparatus depicted in the opening figure%

until the mi,ture is boiling results in a vapor above the li+uid which contains a mi,ture of A and B& The

ratio between A and B in the vapor will be different from the ratio in the li+uid: the ratio in the li+uid will

be determined by how the original mi,ture was prepared' while the ratio in the vapor will be enriched in

the more volatile compound' A #due to ?aoultFs Law' see above%& The vapor goes through the

condenser and is removed from the system& This in turn means that the ratio of compounds in the

remaining li+uid is now different from the initial ratio #i&e&' more enriched in B than the starting li+uid%&

The result is that the ratio in the li+uid mi,ture is changing' becoming richer in component B& This

causes the boiling point of the mi,ture to rise' which in turn results in a rise in the temperature in the

vapor' which results in a changing ratio of A : B in the gas phase #as distillation continues' there is an

increasing proportion of B in the gas phase%& This results in a slowly changing ratio A : B in the

distillate&

.f the difference in vapor pressure between the two components A and B is large #generally e,pressed

as the difference in boiling points%' the mi,ture in the beginning of the distillation is highly enriched in

component A' and when component A has distilled off' the boiling li+uid is enriched in component B&

Continuous distillation[edit]

ain article: Continuous distillation

Continuous distillation is an ongoing distillation in which a li+uid mi,ture is continuously #without

interruption% fed into the process and separated fractions are removed continuously as output streams

as time passes during the operation& Continuous distillation produces at least two output fractions'

including at least one volatiledistillate fraction' which has boiled and been separately captured as a

vapor condensed to a li+uid& There is always a bottoms #or residue% fraction' which is the least volatile

residue that has not been separately captured as a condensed vapor&

Continuous distillation differs from batch distillation in the respect that concentrations should not

change over time& Continuous distillation can be run at asteady statefor an arbitrary amount of time&

4or any source material of specific composition' the main variables that affect the purity of products in

continuous distillation are the reflu, ratio and the number of theoretical e+uilibrium stages #practically'

the number of trays or the height of pacing%& ?eflu, is a flow from the condenser bac to the column'

which generates a recycle that allows a better separation with a given number of trays& @+uilibrium

stages are ideal steps where compositions achieve vaporli+uid e+uilibrium' repeating the separation

process and allowing better separation given a reflu, ratio& A column with a high reflu, ratio may have

fewer stages' but it reflu,es a large amount of li+uid' giving a wide column with a large holdup&

Conversely' a column with a low reflu, ratio must have a large number of stages' thus re+uiring a taller

column&

eneral i!"ro#e!ents[edit]

Both batch and continuous distillations can be improved by maing use of a fractionating columnon

top of the distillation flas& The column improves separation by providing a larger surface area for the

vapor and condensate to come into contact& This helps it remain at e+uilibrium for as long as possible&
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The column can even consist of small subsystems #FtraysF or FdishesF% which all contain an enriched'

boiling li+uid mi,ture' all with their own vaporli+uid e+uilibrium&

There are differences between laboratory6scale and industrial6scale fractionating columns' but the

principles are the same& @,amples of laboratory6scale fractionating columns #in increasing efficiency%

include

Air condenser

!igreu, column#usually laboratory scale only%

;aced column#paced with glass beads' metal pieces' or other chemically inert material%

Spinning band distillationsystem&

Laboratory scale distillation[edit]

Typical laboratory distillation unit

Laboratory scale distillations are almost e,clusively run as batch distillations& The device used in

distillation' sometimes referred to as a still'consists at a minimum of a re$oilerorpotin which the

source material is heated' a condenserin which the heatedvapouris cooled bac to the li+uid state'

and a recei#erin which the concentrated or purified li+uid' called the distillate' is collected& Several

laboratory scale techni+ues for distillation e,ist #see alsodistillation types%&

%i!"le distillation[edit]

.n si!"le distillation' the vapor is immediately channeled into a condenser& Conse+uently' the

distillate is not pure but rather its composition is identical to the composition of the vapors at the given

temperature and pressure& That concentration follows ?aoultFs law&
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As a result' simple distillation is effective only when the li+uid boiling points differ greatly #rule of thumb

is 05 C%()3*or when separating li+uids from non6volatile solids or oils& 4or these cases' the vapor

pressures of the components are usually sufficiently different that the distillate may be sufficiently pure

for its intended purpose&

&ractional distillation[edit]ain article: Fractional distillation

4or many cases' the boiling points of the components in the mi,ture will be sufficiently close that

?aoultFs law must be taen into consideration& Therefore' 'ractional distillationmust be used in order

to separate the components by repeated vapori-ation6condensation cycles within a paced

fractionating column& This separation' by successive distillations' is also referred to as recti'ication&()5*

As the solution to be purified is heated' its vapors rise to the fractionating column& As it rises' it cools'

condensing on the condenser walls and the surfaces of the pacing material& "ere' the condensate

continues to be heated by the rising hot vaporsK it vapori-es once more& "owever' the composition of

the fresh vapors are determined once again by ?aoultFs law& @ach vapori-ation6condensation cycle

#called atheoretical plate% will yield a purer solution of the more volatile component& ()7*.n reality' each

cycle at a given temperature does not occur at e,actly the same position in the fractionating

columnK theoretical plateis thus a concept rather than an accurate description&


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Dimethyl sulfo,ideusually boils at )= C& Gnder a vacuum' it distills off into the receiver at only 8> C&

(er)in trian*le distillation setu"

1:Stirrer bar/anti6bumping granules 2:Still pot 3:4ractionating column 4:Thermometer/Boiling point temperature5:Teflon

tap ) 6:Cold finger 7:Cooling water out 8:Cooling water in 9:Teflon tap 0 10:!acuum/gas inlet 11:Teflon tap 1 12:Still

receiver

+acuu! distillation[edit]

ain article: acuum distillation
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11/28

Some compounds have very high boiling points& To boil such compounds' it is often better to lower the

pressure at which such compounds are boiled instead of increasing the temperature& $nce the

pressure is lowered to the vapor pressure of the compound #at the given temperature%' boiling and the

rest of the distillation process can commence& This techni+ue is referred to as #acuu!

distillationand it is commonly found in the laboratory in the form of therotary evaporator&

This techni+ue is also very useful for compounds which boil beyond theirdecomposition

temperatureat atmospheric pressure and which would therefore be decomposed by any attempt to

boil them under atmospheric pressure&

,olecular distillationis vacuum distillation below the pressure of >&>)torr&()=*>&>) torr is one order of

magnitude abovehigh vacuum'where fluids are in thefree molecular flowregime' i&e& themean free

pathof molecules is comparable to the si-e of the e+uipment& The gaseous phase no longer e,erts

significant pressure on the substance to be evaporated' and conse+uently' rate of evaporation no

longer depends on pressure& That is' because the continuum assumptions of f luid dynamics no longer

apply' mass transport is governed by molecular dynamics rather than fluid dynamics& Thus' a short

path between the hot surface and the cold surface is necessary' typically by suspending a hot plate

covered with a film of feed ne,t to a cold plate with a line of sight in between&


12/28

Short path vacuum distillation apparatus with vertical condenser #cold finger%' to minimi-e the distillation pathK1:Still pot

with stirrer bar/anti6bumping granules 2:Cold finger bent to direct condensate 3:Cooling water out 4:cooling water

in 5:!acuum/gas inlet 6:Distillate flas/distillate&

%hort "ath distillationis a distillation techni+ue that involves the distillate travelling a short distance'

often only a few centimeters' and is normally done at reduced pressure& (0>*A classic e,ample would be

a distillation involving the distillate travelling from one glass bulb to another' without the need for a

condenser separating the two chambers& This techni+ue is often used for compounds which are

unstable at high temperatures or to purify small amounts of compound& The advantage is that the

heating temperature can be considerably lower #at reduced pressure% than the boiling point of the

li+uid at standard pressure' and the distillate only has to travel a short distance before condensing& A

short path ensures that little compound is lost on the sides of the apparatus& The Mugelrohris a ind of

a short path distillation apparatus which often contain multiple chambers to collect distillate fractions&

/one distillation[edit]9one distillation is a distillation process in long container with partial melting of refined matter in

moving li+uid -one and condensation of vapor in the solid phase at condensate pulling in cold area&

The process is wored in theory& Hhen -one heater is moving from the top to the bottom of the

container then solid condensate with irregular impurity distribution is forming& Then most pure part of

the condensate may be e,tracted as product& The process may be iterated many times by moving

#without turnover% the received condensate to the bottom part of the container on the place of refined

matter& The irregular impurity distribution in the condensate #that is efficiency of purification% increases

with number of repetitions of the process& 9one distillation is a distillation analog of -one

recrystalli-ation& .mpurity distribution in the condensate is described by nown e+uations of -one

recrystalli-ation with various numbers of iteration of process with replacement distribution efficient

of crystalli-ation on separation factor N of distillation&(0)*(00*

ther ty"es[edit]

The process ofreactive distillationinvolves using the reaction vessel as the still& .n this

process' the product is usually significantly lower6boiling than its reactants& As the product is

formed from the reactants' it is vapori-ed and removed from the reaction mi,ture& This techni+ue
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13/28

is an e,ample of a continuous vs& a batch processK advantages include less downtime to charge

the reaction vessel with starting material' and less worup& Distillation Jover a reactantJ could be

classified as a reactive distillation& .t is typically used to remove volatile impurity from the

distallation feed& 4or e,ample a littlelimemay be added to remove carbon dio,ide from water

followed by a second distillation with a littlesulphuric acidadded to remove traces of ammonia&

Catalytic distillationis the process by which the reactants are cataly-ed while being distilled to

continuously separate the products from the reactants& This method is used to assist e+uilibrium

reactions reach completion&

;ervaporationis a method for the separation of mi,tures of li+uids by partial vapori-ation

through a non6porous membrane&

@,tractive distillationis defined as distillation in the presence of a miscible' high boiling'

relatively non6volatile component' the solvent' that forms no a-eotropewith the other components

in the mi,ture&

4lash evaporation#or partial evaporation% is the partialvapori-ationthat occurs when a

saturated li+uid stream undergoes a reduction in pressure by passing through a throttling valveor

other throttling device& This process is one of the simplest unit operations' being e+uivalent to a

distillation with only one e+uilibrium stage&

Codistillation is distillation which is performed on mi,tures in which the two compounds are

not miscible&

The unit process ofevaporationmay also be called JdistillationJ:

.nrotary evaporationa vacuum distillation apparatus is used to remove bul solventsfrom a

sample& Typically the vacuum is generated by a water aspiratoror amembrane pump&

.n augelrohra short path distillation apparatus is typically used #generally in combination

with a #high% vacuum% to distill high boiling #O 1>> C% compounds& The apparatus consists of an

oven in which the compound to be distilled is placed' a receiving portion which is outside of the

oven' and a means of rotating the sample& The vacuum is normally generated by using a high

vacuum pump&

$ther uses:

Dry distillationor destructive distillation'despite the name' is not truly distillation' but rather

a chemical reactionnown aspyrolysisin which solid substances are heated in an inert

orreducingatmosphere and any volatile fractions' containing high6boiling li+uids and products of

pyrolysis' are collected& The destructive distillation of woodto give methanolis the root of its

common name #ood alcohol&

4ree-e distillationis an analogous method of purification usingfree-inginstead of

evaporation& .t is not truly distillation' but a recrystalli-ationwhere the product is themother li+uor'

and does not produce products e+uivalent to distillation& This process is used in the production

of ice beerand ice wineto increase ethanol and sugarcontent' respectively& .t is also used to

produceappleEac&Gnlie distillation' free-e distillation concentrates poisonous congeners rather
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14/28

than removing themK As a result' many countries prohibit such appleEac as a health measure&

"owever' reducing methanol with the absorption of 3A molecular sieveis a practical method for

production&(01*Also' distillation by evaporation can separate these since they have different boiling

points&

Azeotropic distillation[edit]

ain article:$%eotropic distillation

.nteractions between the components of the solution create properties uni+ue to the solution' as most

processes entail nonideal mi,tures' where?aoultFs lawdoes not hold& Such interactions can result in a

constant6boilingaeotro"ewhich behaves as if it were a pure compound #i&e&' boils at a single

temperature instead of a range%& At an a-eotrope' the solution contains the given component in the

same proportion as the vapor' so that evaporation does not change the purity' and distillation does not

effect separation& 4or e,ample'ethyl alcoholandwaterform an a-eotrope of =5&7P at 8&) C&

.f the a-eotrope is not considered sufficiently pure for use' there e,ist some techni+ues to brea the

a-eotrope to give a pure distillate& This set of techni+ues are nown as aeotro"ic distillation& Some

techni+ues achieve this by JEumpingJ over the a-eotropic composition #by adding an additional

component to create a new a-eotrope' or by varying the pressure%& $thers wor by chemically or

physically removing or se+uestering the impurity& 4or e,ample' to purify ethanol beyond =5P' a drying

agent or a #desiccantsuch as potassium carbonate% can be added to convert the soluble water into

insoluble water of crystalli-ation&


15/28

This method can remove the need to add other chemicals to a distillation' but it has two potential

drawbacs&

Gnder negative pressure' power for a vacuum source is needed and the reduced boiling points of the

distillates re+uires that the condenser be run cooler to prevent distillate vapours being lost to the

vacuum source& .ncreased cooling demands will often re+uire additional energy and possibly newe+uipment or a change of coolant&

Alternatively' if positive pressures are re+uired' standard glassware can not be used' energy must be

used for pressuri-ation and there is a higher chance of side reactions occurring in the distillation' such

as decomposition' due to the higher temperatures re+uired to effect boiling&

A unidirectional distillation will rely on a pressure change in one direction' either positive or negative&

(ressure.sin* distillation[edit]

Further in&ormation:'ressureS#ing Distillation (section on the main $%eotrope page)

;ressure6swing distillation is essentially the same as the unidirectional distillation used to brea

a-eotropic mi,tures' but here bothpositive and negative pressures may be employed&

This improves the selectivity of the distillation and allows a chemist to optimi-e distillation by avoiding

e,tremes of pressure and temperature that waste energy& This is particularly important in commercial

applications&

$ne e,ample of the application of pressure6swing distillation is during the industrial purification of ethyl

acetateafter its catalytic synthesis fromethanol&

Industrial distillation[edit]

Typical industrial distillation towers

ain article: Continuous distillation
http://en.wikipedia.org/w/index.php?title=Distillation&action=edit&section=18http://en.wikipedia.org/wiki/Azeotrope#Pressure_swing_distillationhttp://en.wikipedia.org/wiki/Azeotrope#Pressure_swing_distillationhttp://en.wikipedia.org/wiki/Azeotrope#Pressure_swing_distillationhttp://en.wikipedia.org/wiki/Azeotrope#Pressure_swing_distillationhttp://en.wikipedia.org/wiki/Ethyl_acetatehttp://en.wikipedia.org/wiki/Ethyl_acetatehttp://en.wikipedia.org/wiki/Ethanolhttp://en.wikipedia.org/w/index.php?title=Distillation&action=edit&section=19http://en.wikipedia.org/wiki/Continuous_distillationhttp://en.wikipedia.org/wiki/File:Colonne_distillazione.jpghttp://en.wikipedia.org/wiki/File:Colonne_distillazione.jpghttp://en.wikipedia.org/w/index.php?title=Distillation&action=edit&section=18http://en.wikipedia.org/wiki/Azeotrope#Pressure_swing_distillationhttp://en.wikipedia.org/wiki/Azeotrope#Pressure_swing_distillationhttp://en.wikipedia.org/wiki/Ethyl_acetatehttp://en.wikipedia.org/wiki/Ethyl_acetatehttp://en.wikipedia.org/wiki/Ethanolhttp://en.wikipedia.org/w/index.php?title=Distillation&action=edit&section=19http://en.wikipedia.org/wiki/Continuous_distillation


16/28

Large scale industrial distillationapplications include both batch and continuous fractional' vacuum'

a-eotropic' e,tractive' and steam distillation& The most widely used industrial applications of

continuous' steady6state fractional distillation are inpetroleum refineries' petrochemicaland chemical

plantsandnatural gas processingplants&

To control and optimi-e such industrial distillation' a standardi-ed laboratory method' AST< D7' isestablished& This test method e,tends to the atmospheric distillation of petroleum products using a

laboratory batch distillation unit to +uantitatively determine the boiling range characteristics of

petroleum products&

Automatic Distillation Gnit for the determination of the boiling range of petroleum products at atmospheric pressure

.ndustrial distillation()5*(03*is typically performed in large' vertical cylindrical columns nown

asdistillation toersor distillation colu!nswith diameters ranging from about 75 centimeters to

)7 meters and heights ranging from about 7 meters to => meters or more& Hhen the process feed has

a diverse composition' as in distillingcrude oil'li+uid outlets at intervals up the column allow for the

withdrawal of different &ractionsor products having differentboiling pointsor boiling ranges& The

JlightestJ products #those with the lowest boiling point% e,it from the top of the columns and the

JheaviestJ products #those with the highest boiling point% e,it from the bottom of the column and are

often called the$otto!s&
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17/28

Diagram of a typical industrial distillation tower

.ndustrial towers use reflu,to achieve a more complete separation of products& ?eflu, refers to the

portion of the condensed overhead li+uid product from a distillation or fractionation tower that is

returned to the upper part of the tower as shown in the schematic diagram of a typical' large6scale

industrial distillation tower& .nside the tower' the downflowing reflu, li+uid provides cooling and

condensation of the upflowing vapors thereby increasing the efficiency of the distillation tower& The

more reflu, that is provided for a given number of theoretical plates'the better the towerFs separation

of lower boiling materials from higher boiling materials& Alternatively' the more reflu, that is provided

for a given desired separation' the fewer the number of theoretical plates re+uired& Chemical

engineersmust choose what combination of reflu, rate and number of plates is both economically and

physically feasible for the products purified in the distillation column&

Such industrial fractionating towers are also used in cryogenicair separation' producingli+uid

o,ygen'li+uid nitrogen'and high purity argon& Distillation of chlorosilanesalso enables the production

of high6puritysiliconfor use as a semiconductor&
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18/28

Section of an industrial distillation tower showing detail of trays with bubble caps

Design and operation of a distillation tower depends on the feed and desired products& 2iven a simple'

binary component feed' analytical methods such as the>P

efficiente+uilibrium stage&"ence' a distillation tower needs more trays than the number of theoretical

vaporli+uid e+uilibrium stages& A variety of models have been postulated to estimate tray efficiencies&

.n modern industrial uses' a pacing material is used in the column instead of trays when low pressure

drops across the column are re+uired& $ther factors that favor pacing are: vacuum systems' smaller

diameter columns' corrosive systems' systems prone to foaming' systems re+uiring low li+uid holdup'

and batch distillation& Conversely' factors that favorplate columnsare: presence of solids in feed' high

li+uid rates' large column diameters' comple, columns' columns with wide feed composition variation'

columns with a chemical reaction' absorption columns' columns limited by foundation weight tolerance'

low li+uid rate' large turn6down ratio and those processes subEect to process surges&
http://en.wikipedia.org/wiki/McCabe%E2%80%93Thiele_methodhttp://en.wikipedia.org/wiki/McCabe%E2%80%93Thiele_methodhttp://en.wikipedia.org/wiki/McCabe%E2%80%93Thiele_methodhttp://en.wikipedia.org/wiki/Distillation#cite_note-Perry-15http://en.wikipedia.org/wiki/Distillation#cite_note-SeaderHenley-25http://en.wikipedia.org/wiki/Fenske_equationhttp://en.wikipedia.org/wiki/Fenske_equationhttp://en.wikipedia.org/wiki/Fenske_equationhttp://en.wikipedia.org/wiki/Fenske_equationhttp://en.wikipedia.org/wiki/Distillation#cite_note-Perry-15http://en.wikipedia.org/wiki/Simulationhttp://en.wikipedia.org/wiki/Equilibrium_stagehttp://en.wikipedia.org/wiki/Equilibrium_stagehttp://en.wikipedia.org/wiki/Equilibrium_stagehttp://en.wikipedia.org/wiki/Plate_columnhttp://en.wikipedia.org/wiki/Plate_columnhttp://en.wikipedia.org/wiki/Plate_columnhttp://en.wikipedia.org/wiki/File:Bubble_Cap_Trays.PNGhttp://en.wikipedia.org/wiki/McCabe%E2%80%93Thiele_methodhttp://en.wikipedia.org/wiki/Distillation#cite_note-Perry-15http://en.wikipedia.org/wiki/Distillation#cite_note-SeaderHenley-25http://en.wikipedia.org/wiki/Fenske_equationhttp://en.wikipedia.org/wiki/Fenske_equationhttp://en.wikipedia.org/wiki/Distillation#cite_note-Perry-15http://en.wikipedia.org/wiki/Simulationhttp://en.wikipedia.org/wiki/Equilibrium_stagehttp://en.wikipedia.org/wiki/Plate_column


19/28

Large6scale' industrial vacuum distillation column(07*

This pacing material can either be random dumped pacing #)1J wide% such as ?aschig

ringsorstructured sheet metal&Li+uids tend to wet the surface of the pacing and the vapors pass

across this wetted surface' where mass transfertaes place& Gnlie conventional tray distillation in

which every tray represents a separate point of vaporli+uid e+uilibrium' the vaporli+uid e+uilibrium

curve in a paced column is continuous& "owever' when modeling paced columns' it is useful to

compute a number of Jtheoretical stagesJ to denote the separation efficiency of the paced column

with respect to more traditional trays& Differently shaped pacings have different surface areas and

void space between pacings& Both of these factors affect pacing performance&

Another factor in addition to the pacing shape and surface area that affects the performance of

random or structured pacing is the li+uid and vapor distribution entering the paced bed& The number

oftheoretical stagesre+uired to mae a given separation is calculated using a specific vapor to li+uid

ratio& .f the li+uid and vapor are not evenly distributed across the superficial tower area as it enters the

paced bed' the li+uid to vapor ratio will not be correct in the paced bed and the re+uired separation

will not be achieved& The pacing will appear to not be woring properly& Theheight e+uivalent to a

theoretical plate#"@T;% will be greater than e,pected& The problem is not the pacing itself but the

mal6distribution of the fluids entering the paced bed& Li+uid mal6distribution is more fre+uently the

problem than vapor& The design of the li+uid distributors used to introduce the feed and reflu, to a

paced bed is critical to maing the pacing perform to it ma,imum efficiency&


20/28

The goal of multi6effect distillation is to increase the energy efficiency of the process' for use in

desalination' or in some cases one stage in the production of ultrapure water& The number of effects is

inversely proportional to the HQh/m1of water recovered figure' and refers to the volume of water

recovered per unit of energy compared with single6effect distillation& $ne effect is roughly

717 HQh/m1&

effects with thermal energy input' as

mentioned in the article&

!apor compression evaporationCommercial large6scale units can achieve around 80 effects

with electrical energy input' according to manufacturers&

There are many other types of multi6effect distillation processes' including one referred to as simply

multi6effect distillation #


21/28

Diagram of an industrial6scale vacuum distillation column as commonly used inoil

refineries

A rotary evaporatoris able to distill solvents more +uicly at lower temperatures

through the use of a vacuum&

Distillation using semi6microscale apparatus& The Eointless design eliminates the

need to fit pieces together& The pear6shaped flas allows the last drop of residue to

be removed' compared with a similarly6si-ed round6bottom flasThe small holdup

volume prevents losses& A pig is used to channel the various distillates into three

receiving flass& .f necessary the distillation can be carried out under vacuum using

the vacuum adapter at the pig&

See also[edit]
http://en.wikipedia.org/wiki/Oil_refineryhttp://en.wikipedia.org/wiki/Oil_refineryhttp://en.wikipedia.org/wiki/Oil_refineryhttp://en.wikipedia.org/wiki/Rotary_evaporatorhttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Round-bottom_flaskhttp://en.wikipedia.org/w/index.php?title=Distillation&action=edit&section=24http://en.wikipedia.org/wiki/File:Semi-microscale_distillation.jpghttp://en.wikipedia.org/wiki/File:Rotavapor.jpghttp://en.wikipedia.org/wiki/File:Vacuum_Column.pnghttp://en.wikipedia.org/wiki/Oil_refineryhttp://en.wikipedia.org/wiki/Oil_refineryhttp://en.wikipedia.org/wiki/Rotary_evaporatorhttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Round-bottom_flaskhttp://en.wikipedia.org/w/index.php?title=Distillation&action=edit&section=24


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References[edit]

)& u!" u" "arwood' Laurence%&$ short history o& theart o& distillation: &rom the

beginnings up to the death o&Cellier !lumenthal& B?.LL& pp& 58'=& .SBI=86=>6>36>>7)86)&?etrieved 0= une 0>)>&

1& u!" u" Taylor' 4& #)=35%&JThe evolution of the stillJ&$nnals o&

Science5#1%:)5& doi:)>&)>>/>>>118=35>>0>)35)&
http://en.wikipedia.org/w/index.php?title=Distillation&action=edit&section=25http://en.wikipedia.org/wiki/Distillation#cite_ref-1http://en.wikipedia.org/wiki/Distillation#cite_ref-1http://en.wikipedia.org/wiki/Distillation#cite_ref-1http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Special:BookSources/978-0-632-02017-1http://en.wikipedia.org/wiki/Special:BookSources/978-0-632-02017-1http://en.wikipedia.org/wiki/Distillation#cite_ref-Forbes1970_2-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Forbes1970_2-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Forbes1970_2-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Forbes1970_2-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Forbes1970_2-1http://books.google.com/books?id=XeqWOkKYn28Chttp://books.google.com/books?id=XeqWOkKYn28Chttp://books.google.com/books?id=XeqWOkKYn28Chttp://books.google.com/books?id=XeqWOkKYn28Chttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Special:BookSources/978-90-04-00617-1http://en.wikipedia.org/wiki/Distillation#cite_ref-Taylor_3-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Taylor_3-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Taylor_3-0http://en.wikipedia.org/wiki/Digital_object_identifierhttp://dx.doi.org/10.1080%2F00033794500201451http://dx.doi.org/10.1080%2F00033794500201451http://en.wikipedia.org/w/index.php?title=Distillation&action=edit&section=25http://en.wikipedia.org/wiki/Distillation#cite_ref-1http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Special:BookSources/978-0-632-02017-1http://en.wikipedia.org/wiki/Special:BookSources/978-0-632-02017-1http://en.wikipedia.org/wiki/Distillation#cite_ref-Forbes1970_2-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Forbes1970_2-1http://books.google.com/books?id=XeqWOkKYn28Chttp://books.google.com/books?id=XeqWOkKYn28Chttp://books.google.com/books?id=XeqWOkKYn28Chttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Special:BookSources/978-90-04-00617-1http://en.wikipedia.org/wiki/Distillation#cite_ref-Taylor_3-0http://en.wikipedia.org/wiki/Digital_object_identifierhttp://dx.doi.org/10.1080%2F00033794500201451http://dx.doi.org/10.1080%2F00033794500201451


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4. R ump up to:a b"aw' Stephen2& #0>)0%& JHine' women and

poisonJ& arco 'olo in China&?outledge& pp& )38)3& .SBI=86)6)1360853068& JThe earliestpossible period seems to be the@astern "an dynasty &&& the mostliely period for the beginning of

true distillation of spirits for driningin China is during the in andSouthern Song dynastiesJ

5& u!" u" Sarton' 2eorge#)=85%& +ntroduction to the history o&

science& ?& @& Mrieger ;ub& Co&p& )35& .SBI>60856)8068&

7& u!" u" "olmyard' @ric ohn#)==>%&$lchemy& Courier Dover;ublications& p& 51& .SBI>6376070=68&

8& u!" u"


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Alchemywebsite&com& ?etrieved on0>)36>360>&

& u!" u" +ndustrialngineering Chemistry#)=17% p&788

=& u!" u" Sealing Techni+ue'accessed )7 Iovember 0>>7&

)>& u!" u" Traditional Alembic

;ot Still' accessed )7 Iovember0>>7&

11. R ump up to:a bD& 4& $thmer#)=0% JDistillation Some Steps inits DevelopmentJ' in H& 4& 4urter

#ed%$ Century o& Chemicalngineering.SBI >61>763>=561

)0& u!" u"A& Coffey British;atent 5=83' 5 August )1>

)1& u!" u" G&S& ;atent)='7==.mprovement in theAmmonia6Soda


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)3& u!" u" ST>8 Separation ofli+uidli+uid mi,tures #solutions%'

D.DAC by.G;AC15. R ump up to:a bcd;erry' ?obert

"& and 2reen' Don H)=3%& 'errys Chemical ngineers-andboo#7th ed&%& 0)& u!" u" Mravcheno' A&.&

#0>))%& J9one distillation: a newmethod of refiningJ&'roblems o&
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atomic science and technology#in?ussian% 6#)=%: 0307&

00& u!" u" Mravcheno' A&.>)3%& J9one distillation:EustificationJ& 'roblems o& atomicscience and technology1#0>%: 7375&

01& u!" u" Study on


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08& u!" u" >7%& JA

new method to assess li+uiddistributor +ualityJ& Chemicalngineering and'rocessing45#))%:)>))&doi:)>&)>)7/E&cep&0>>7&>5&>>1

&0=& u!" u" Munesh' ohn 2&K

Lahm' LawrenceK anagi' Taashi#)=8%& JCommercial scalee,periments that provide insight onpaced towerdistributorsJ& +ndustrial 1ngineering Chemistry
http://en.wikipedia.org/wiki/Distillation#cite_ref-Moore_27-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Moore_27-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Moore_27-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Spiegel_28-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Spiegel_28-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Spiegel_28-0http://en.wikipedia.org/wiki/Digital_object_identifierhttp://dx.doi.org/10.1016%2Fj.cep.2006.05.003http://en.wikipedia.org/wiki/Distillation#cite_ref-Kunesh_29-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Kunesh_29-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Kunesh_29-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Moore_27-0http://en.wikipedia.org/wiki/Distillation#cite_ref-Spiegel_28-0http://en.wikipedia.org/wiki/Digital_object_identifierhttp://dx.doi.org/10.1016%2Fj.cep.2006.05.003http://dx.doi.org/10.1016%2Fj.cep.2006.05.003http://en.wikipedia.org/wiki/Distillation#cite_ref-Kunesh_29-0


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/esearch26#=%:)35& doi:)>&)>0)/ie>>>7=a>0)&
http://en.wikipedia.org/wiki/Digital_object_identifierhttp://dx.doi.org/10.1021%2Fie00069a021http://en.wikipedia.org/wiki/Digital_object_identifierhttp://dx.doi.org/10.1021%2Fie00069a021

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