DISTILLATION SYSTEM
Distillation - a process in which a liquid or
vapour mixture of two or more substances is
separated into its component fractions of
desired purity, by the application and removal
of heat.
DISTILLATION SYSTEM
For any liquid, the individual
molecules within the
Atmospheric pressure, P atm liquid are continuously in
motion
A small percentage of these
molecules attain enough
kinetic energy to leave the
liquid phase
This exerts an opposing
pressure on the
Vapor Pressure, P
atmosphere above the
solution known as the
vapor pressure, P
DISTILLATION SYSTEM
When enough energy, in the form of heat, is imparted
to the solution the vapor pressure becomes equal to
the atmospheric pressure and the liquid begins to
boil
P < P atm P ≥ P atm
DISTILLATION SYSTEM
The vapor
obtained
from a
boiling
liquid,
once
cooled,
will re-
condens
e to a
liquid
known
as the
distillate
The
complet
DISTILLATION SYSTEM e
Separation of one liquid from another
A + B C + D
bp 60 oC bp 100 oC
Pure C?
Pure D?
C + D
Mixture of C + D?
DISTILLATION SYSTEM
TYPES OF DISTILLATION
SYSTEM
TYPES OF DISTILLATION COLUMNS
Batch Columns
• In batch operation, the feed to the column is introduced
batch-wise.
Continuous Columns
• continuous columns process a continuous feed stream. No
interruptions occur unless there is a problem with the
column or surrounding process units.
TYPES OF DISTILLATION SYSTEM
CLASSIFICATION OF CONTINOUS COLUMNS
Nature of feed
◦ Binary column
◦ Multi component column
Number of product streams
◦ Multi product column
Feed exits
◦ Extractive distillation
◦ Azeotropic distillation
Column Internals
◦ Packed columns
◦ Tray columns
TYPES OF DISTILLATION SYSTEM
OTHER TYPES
Simple Distillation
◦ Vapors produced are
immediately channeled
into a condenser which
cools and condenses
the vapors
◦ Used only to separate
liquids whose boiling
points differ by 25C
TYPES OF DISTILLATION SYSTEM
OTHER TYPES
Fractional Distillation
◦ Utilizes two or more vaporization
condensation cyclces, in succession,
to effect separation
◦ The fractionating column causes the
vaporization-condensation cycle to
repeat by providing multiple surfaces
for the cycle to take place
TYPES OF DISTILLATION SYSTEM
Fractional Distillation
As the hot vapors leave the distilling flask,
they condense on the first cold surface,
completing one vaporization-
condensation cycle.
Vapors from the
Distilling flask
TYPES OF DISTILLATION SYSTEM
Fractional Distillation
• Each vapor-condensation (or mini-
distillation) cycle is known as one theoretical
plate
• The length of distillation column required to
provide one theoretical plate of separation is
known as the height equivalent theoretical
plate (HETP)
This cycle will continue until the top of the
column is reached
Vapors from the
Distilling flask
TYPES OF DISTILLATION SYSTEM
OTHER TYPES
Steam Distillation
◦ Methods for distilling compounds which are heat
sensitive
◦ Involves a process using bubbling steam through
heated mixture of the raw material
◦ Applied for aromatic herbs and flowers
Vacuum Distillation
◦ For compounds that have high boiling points
TYPES OF DISTILLATION SYSTEM
OTHER TYPES Air-sensitive
vacuum distillation
◦ For compounds that
have high boiling
points as well as air
sensitive
◦ Perkin Triangle
apparatus can be used
TYPES OF DISTILLATION SYSTEM
OTHER TYPES
Short Path Distillation
◦ Use for compounds which are unstable at high
temperature
◦ Heating temperature can be considerably lower
Destructive Distillation
◦ involves the strong heating of solids (often organic
material) in the absence of oxygen (to prevent
combustion) to evaporate various high-boiling
liquids
TYPES OF DISTILLATION SYSTEM
OTHER TYPES
Pervaporation Distillation
◦ method for the separation of mixtures of liquids by
partial vaporization through a non-porous
membrane.
Dry Distillation
◦ a chemical reaction known as pyrolysis in which
solid substances are heated in a strongly reducing
atmosphere and any volatile fractions are collected.
TYPES OF DISTILLATION SYSTEM
OTHER TYPES
Extractive Distillation
◦ distillation in the presence of a miscible, high
boiling, relatively non-volatile component, the
solvent, that forms no azeotrope with the other
components in the mixture
Flash evaporation
◦ partial vaporization that occurs when a saturated
liquid stream undergoes a reduction in pressure by
passing through a throttling valve or other
throttling device
TYPES OF DISTILLATION SYSTEM
OTHER TYPES
Freeze Distillation
◦ analogous method of purification using freezing
instead of evaporation
◦ It is not truly distillation, and does not produce
products equivalent to distillation
Codistillation
◦ distillation which is performed on mixtures in which
the two compounds are not miscible.
TYPES OF DISTILLATION SYSTEM
