Distillation and Alcohol Production Application

1
Distillation and Alcohol Production Application
Distillation and Alcohol Production Applicaiton
2
Distillation and Alcohol Production Application

• Distillation process
• Types of distillation
• Distillation equipments and properties of them
• Alcohol production
• Distillation of alcohol
• Types of alcohol distillation

3
Distillation

• Distillation is a kind of seperation technique of
  two or more volatile liquid compunds by using the
  difference in boiling points and relative
  volatility.
• The process takes place in a column, and two heat
  exchangers.
• In the column two phases, liquid and gas, are
  distributed to enrich the vapor in more volatile
  compounds and enrich the liquid phase on less
  volatile compounds.
• Mass transfer is the key to a successful
  distillation.

4
(No Transcript)
5
Advantages Disadvantages

• Advantages
• It has simple flowsheet, low capital investment,
  and low risk. If components to be separated have
  a high relative volatility difference and are
  thermally stable, distillation is hard to beat.

• Disadvantages
• Distillation has a low energy efficiency and
  requires thermal stability of compounds at their
  boiling points. It may not be attractive when
  azeotropes are involved or when it is necessary
  to separate high boiling components, present in
  small concentrations, from large volumes of a
  carrier, such as water.

6
Types of Distillation

• Continous Distillation
• Batch Distillation
• Semi-Batch Distillation

7
Continous Distillation

• The mixture which is to be seperated is fed to
  column at one or more points.
• Liquid mixture runs down the column while vapor
  goes up.
• Vapor is produced by partial vaporisation of the
  mixture which is heated in reboiler.
• Then vapor is partially condensed to earn back
  the less volatile compounds to the column to
  seperate as bottom product. (reflux)?

8
Batch Distillation

• The oldest operation used for seperation of
  liquid mixtures.
• Feed is fed from bottom,where includes reboiler,
  to be processed.
• Numbers of accumulator tanks are connected to
  collect the main and the intermediate distillate
  fractions.

9
Semi-batch Distillation

• Semi-batch distillation is very similar to batch
  distillation.
• Feed is introduced to column in a continous or
  semi-continous mode.
• It is suitable for extractive and reactive
  distillations.

10
Comparsion of Distillation Types

• For batch distillation, it is enough to use only
  one column to seperate multicomponent liquid
  mixture.
• One sequence of operation is enough to seperate
  all the components in a mixture.

• For continous distillation, to seperate
  multicomponent liquid mixtures, more than one
  columns are necessary to be used.
• One column is dedicated to seperate a specific
  mixture and specific operation.

11
Equipment Designs

• Plate Columns (Tray Columns)?
• Packed Beds

12
Plate Columns (Tray Columns)?

• It is the most widely used kind of distillation
  column.
• Trays are shaped to maximize the liquid-vapor
  contact and increase the mass transfer area.
• Tray types include sieve, valve and bubble cap.

13
(No Transcript)
14
(No Transcript)
15
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
Advantages Disadvantages

• Advantages
• Least expensive colum for diameters greater than
  0.6m
• The liquid-vapor contact in the cross-flow of
  plate columns is more effective than
  countercurrent-flow in packed columns.
• Cooling coils can be easily added to the plate
  column
• Can handle high liquid flow rates.

• Disadvantages
• Higher pressure drops than packed columns
• Foaming can occur because the liquid is agitated
  by the vapor flowing up through it.

24
Packed Beds

• Packings can be provided either as dumped or
  stacked.
• Dumped packing consistutes of bulk inert
  materials.
• Stacked packing is includes meshwork which has
  the same diameter with the column.
• Important criterias for packings are efficent
  contact (liquid-vapor), resistence to flow, flow
  capacity, resistance of packing against corrosion.

25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28
(No Transcript)
29
(No Transcript)
30
(No Transcript)
31
(No Transcript)
32
Advantages Disadvantages

• When the diameter is less than 0.6m it is less
  expensive than the plate column.
• Packing is able to handle corrosive materials.
• Lower pressure drop than in plate columns.
• Good for thermally sensitive liquids.

• Can break during installation or due to thermal
  expansion.
• Not cost efficient for high liquid flow rates.
• Contact efficiencies are decreased when the
  liquid flow rate is too low.

33
Making of Alcohol

• Alcohols, generally can be created by reduction
  of aldehydes or twice reduction of ketones.
• Ethanol (C2H5OH) can produced by fermantation of
  molases.
• Fermantation is done in a tank and it is cleaned
  and sterilized before the fermantation begins.

34

• Molases have strong concentration of sugar which
  doesn't provide the adequate conditions for
  fermantation. Consequently it must be dilluted to
  concentration of 17 sugar.
• Optimum enviromental pH range is between 4.0 and
  5.0 and optimum temperature is 76F(25C).
• Fermantated molases is called beer and it
  contains 6.5 to 11 alcohol by volume.

35
(No Transcript)
36
Distillation of Alcohol

• Under 1 athmosphere pressure boiling points of
  water and alcohol are 100C and 78.3C.
• Water and ethyl alcohol mixture forms an
  azeotrope in athmospheric pressure at a mole
  fraction of 89.4 of ethyl alcohol which means
  that by simple distillation of ethyl alcohol, it
  cannot be purified more than 95.6 w.
• As distillation equipments, bubble cap trays and
  tray columns are mostly used in alcohol
  distillation.(Figure on left)?

37
Pot Distillation Process (Batch Distillation)?

• Entire batch of beer is heated in a large
  container and alcohol/water vapors are chanelled
  into a distillation column.
• After all the boiling and reflux operations, when
  almost all alcohol is boiled, process is stopped
  and stillage is removed.

38
(No Transcript)
39
(No Transcript)
40

• The basic advantage of pot distillation is its
  simplicity. It has simple equipment system.
  Fermantation and boiling for distillation can
  take place at the same pot, which makes it more
  practical
• The disadvantage of the pot distillation is low
  distillation efficiency. It requires about three
  times more energy comparing to continous
  distillation.

41
Continous-Feed Distillation Process

• Typically it is also known as continous
  distillation.
• Alcohol/liquid mixture is fed to column and it
  flows.
• Flow rate is decreased by trays.
• Mixture boils up in the reboiler and goes up of
  the column to condenser as it contacts with the
  condensed liquid.
• The vapor with high alcohol percent leaves the
  condenser to be collected in accumulator.

42

• The advantage of the continous feed distillation
  process is it's high energy efficiency comparing
  to the pot distillation process. Eventually
  amount of energy required for per liter of
  alcohol is less than in pot distillation. On the
  other hand it can operate for long hours (almost
  8000 hours per annum)?
• The disadvantage of continous feed distillation
  is it needs a little more complicated equipment
  system comparing to the batch distillation.

43
Vacuum Distillation

• Low temperature allows us to achieve higher
  alcohol concentrations.
• At a pressure below 0.1 athmosphere azeotrope
  disappears and enables to distillate to almost
  100 percent alcohol.

44
(No Transcript)
45

• Because of the high operation and installation
  costs, low energy efficiency, vacuum distillation
  appears to be uneconomical in the commercial
  applications.

46
Azeotropic Distillation

• This type of distillation is used for processes
  that produce almost 100 percent alcohol with help
  of an organic solvent and two additional
  distillations.
• A solvent (pentane, gasoline etc.) is added to
  distillation product comming out of the usual
  distillation column.
• Mixture is fed to another distillation column
  which seperates it into a top product and a
  bottom product.
• Distillate of this column is fed to a third
  column which distills out the solvent leaving the
  mixture of alcohol-water.
• Solvent is recycled and never gets out.
• System is hard to design and it is more
  complicated comparing to ordinary distillation
  system.