284330054-Chapter-1-Modern-Separation-process-ppt.ppt

Modern-Separation-process

1. Dr. Krunal Gangawane
Department of Chemical Engineering
IIT Jodhpur
MULTICOMPONENT SEPARATION
PROCESSES
M.Tech- I Semester Chemical Engineering

2. MODERN SEPARATION TECHNIQUES
Faculty Name: Dr. Krunal Gangawane
Subject code : CHL7050
SYLLABUS
Introduction: Review of conventional processes, Recent advances in
separation techniques based on size, surface properties, ionic properties and
other special characteristics of substances, Process concept, Theory and
equipment used in cross flow filtration, cross flow electro filtration, dual
functional filter, Surface based solid -liquid separations involving a second
liquid, Sirofloc filter.

3. •Separation can be defined as an operation by
which a mixture is resolved into its components.
•Separation processes play vital role in process
industries.
•With out separation processes no industry can
exist.
Separations are carried out based on differences in properties such
as size, shape, mass, or chemical affinity between the constituents of
a mixture, and are often classified according to the particular
differences they use to achieve separation.

4. •Every Industrial Process is designed to produce
economically a desired product from a variety of
starting materials through a succession of
treatment steps.
UPSTREAM
PROCESS
Typical Chemical Process
IMPUTRITIES
RAW
MATERIALS
CHEMICAL /
BIOCHEMICAL
TREATMENT
PURFIED
RAW
MATERIAL
DOWN
STREAM
PROCESS
COMBINED
PRODUCT
BY PRODUCT
PRODUCT

5. Physical Treatment before reaction step is required for
preparing the raw material – upstream processing or pre
treatment step.
The raw material undergo a number of physical
treatment steps to put them in the form in which they
can be treated chemically.
• Iron pyrites ore is dried in rotary kiln and ground to
– 200 mesh for sulfur and sulfur dioxide production.
• Calcium carbide is pulverized for the production of
acetylene.
•Phosphate rock ground for production of elemental
phosphorous, phosphorous pentoxide and phosphoric
acid.
Chemical Processes

6. •Lime stone is pulverized, classified, treated in flotation
cell for the beneficiation of limestone.
•Clay and limestone are pulverized for cement
manufacture.
•Rice bran is palletized before extraction

7. Separating
Device
Feed
stream
Separating
agent
Product stream
By product stream
Schematic representation of a Separation Process

8. •One or more feed with two or more species enter the
unit
•Two or more products of different compositions leave
the unit
•A separating agent is required for the separation
–Energy separating agent
–Mass separating agent
•Often separating agents will cause formation of second
phase of matter.
•A separation is accomplished if the generated phase has a
different composition from the feed.

9. Primary Basis for Separation
• Any separation depends on the use of one or more differences in
properties of components
•Greater the differences in properties, easier is the separation by
that method
–Vapor Pressure-distillation
–Diffusivity and Solubility-reverse Osmosis
–Molecular Size-ultra Filtration

10. Separation factor
•Proposed as a measure of degree of separation obtainable for particular
mixture and a separation technique
•For a binary mixture it is the ratio of the concentration ratio of A and B
in one phase to that in other
α
ij = x
i1 / x
j1 = k
i / k
j
x
i2 /x
j2
ki- equilibrium ratio
•Vapour liquid system-relative volatility
•liquid-liquid system-selectivity
•unity-no separation possible
•larger the value, greater the separation
•separation factor is quite large-separation possible in a single stage

11. Classification of Separation Processes
•Separation may be achieved by chemical, mechanical and
physical/diffusion methods
•Chemical method ordinarily destroys the original substance
and hence used rarely.
•The mechanical /Physical / Diffusion methods are further
classified as equilibrium separation process, rate governed
separation process and mechanical separation processes.

12. PROCESS FEED AGENT PRODUCT PRINCIPLE EXAMPLE
EVAPORATION L H L+V DIFFERENCES IN
VOLATILITY
CONCENTRATION OF
SOLUTIONS
DISTILLATION L&OR V H L+V DIFFERENCES IN
VOLATILITY
PETROLEUM
PRODUCTS,ALCOHOL
ABSORPTION G L( NV) L+V PREFERENTIAL
SOLUBILITY
RECOVERY OF CO
2
,SO
2
STRIPPING L G(NC) L+V DIFFERENCES IN
VOLATILITY
REMOVAL OF LIGHT
HYDROCARBONS
LIQUID
EXTRACTION
L L L+L PREFERENTIAL
SOLUBILITY
PENCILLIN RECOVERY
LEACHING OR
WASHING
S L L+S PREFERENTIAL
SOLUBILITY
RECOVERY OF
MINERALS FROM ORE
CRYSTALLIZATION L H(REMOVAL
)
L+S DIFFERENCES IN
SOLUBILITY
SUGAR,CITRIC ACID
DRYING S H S+V DIFFERENCES IN
VOLATILITY
FOOD DEHYDRATION
ADSORPTION G(OR)L S L(OR)G DIFFERENCES IN
CHEMICAL
AFFINITY
DRYING OF
GASES,DECOLOURATION
OF SOLNS.
ION EXCHANGE L S( RESIN) L+S ELECTRICAL
CHARGE
+ADSORPTION
WATER SOFTENING
FREEZE DRYING FROZEN
WATER
H S+V SUBLIMATION OF
WATER
DEHYRATION OF FOOD
Equilibrium Processes

13. PROCESS FEED AGENT PRODUCT PRINCIPLE EXAMPLE
DIALYSIS L M SELECTIVE L+L DIFFERENCE IN
DIFFUSIONAL RATE
ARTIFICIAL
KIDNEY
ELECTRO
DIALYSIS
L M +ELE.FIELD L+L DIFFERENCE IN
IONIC MOBILITY
DESALINATION OF
BRACKISH WATER
ULTRA
FILTRATION
L+
COLLOID
M+PRESSURE GRADIENT L+L DIFFERENCE IN
PERMEABILITIES
PROTEIN
CONCENTRATION
REVERSE
OSMOSIS
L M+PRESSURE GRADIENT L+L DIFFERENCE IN
COMBINED
SOLUBILITIUES
AND DIFFUSIVITIES
IN MEMBRANES
DESALINATION OF
SEA WATER
GAS
PERMEATION
G M+PRESSURE GRADIENT G DIFFERENCE IN
SOLUBILITIES AND
TRASPORT RATE
THRO’MEMBRANES
GAS REVOCERY/
PURIFICATION OF
HYDROGEN
THERMAL
DIFFUSION
G(OR)L TEMP.GRADIENT G(OR) L DIFFERENCE IN
RATE OF THERMAL
DIFFUSION
SEPARATION OF
ISOTOPES
Rate Governed Processes

14. PROCESS FEED AGENT PRODUCT PRINCIPLE EXAMPLE
FILTRATION L+S FILTER
MEDIUM+
PRESSURE
L+S SIZE Separation of
Solids form Slurry
SETTLING L+S GRAVITY L+S DIFFERENCE
IN DENSITY
Clarification of
Solutions
CENTRIFUGING L+S(OR)L CENTRIFUGA
L FORCE
L+S(OR)L DIFFERENCE
IN DENSITY
Recovery of
Insoluble Products
CYCLONE
SEPARATION
G+S(OR)L INERTIAL
FORCE
G+S(OR)L DIFFERENCE
IN DENSITY
Recovery of
Insoluble Products
ELECTROSTATIC
PRECIPITATION
G+S(FINE ELECTRICAL
FIELD
G+S CHARGE ON
FINE SOLID
PARTICLES
Dust Removal
from Stack Gasses
Mechanical Processes

15. Choice of Separation Processes
The criteria for choice for recovery of products depends on
1.Nature of the Feed (Gas Liquid or Solid)
2.Concentration of Product in the Feed
3.Physical and Chemical Characteristics of the desired product
4.Impurities in the feed
5.Intended use of the product
6.The minimal acceptance standard of purity
7.Marketability of the product.

16. Selected Separation Processes
1.Filtration
2.Distillation
3.Extraction
4.Crystallization
5.Evaporation
6.Supercritical Extraction
7.Gel Electrophoresis
8.Chromatography Separations
9.Gel Filtration
10.Membrane Separation Processes

17. Distillation
Removal of liquid mixtures into their components by
vaporization.
The property exploited is the relative volatility.
More the relative volatility between the components to be
separated easier will be the separation.
Less the relative volatility difficult will be the separation.

Azeotropic system.
Simple distillation, Continuous distillation, steam distillation,
extractive distillation, azeotropic distillation.
Packed column distillation, plate column distillation.
Steam distillation.

18. Filtration
•Used for heterogeneous mixtures.
•The general problem of the separation of solid particles from liquids can be
solved by using a wide variety of methods, depending on the types of solids,
the proportion of solid to liquid in the mixture, viscosity of the solution, and
other factors.
•In filtration, a pressure difference is setup that causes the fluid to flow
through small holes in a screen or cloth which block the passage of large
particle; these in turn, buildup on the cloth as a porous cake.
•Different filtration includes: Batch filtration, continuous filtration, vacuum
filtration, pressure filtration
•

19. Extraction
Removal of active ingredient from mixture using a solvent.
Liquid-liquid extraction is also called as solvent extraction. Solid
liquid extraction is called leaching.
Extraction and leaching exploits the differences in solubility of
solutes in different solvents.The solubility is expressed as
distribution coefficient or selectivity.

Used to recover heat sensitive material from solution.
Penicillin G is an antibiotic which is recovered from fermentation
broths by counter current solvent extraction.
Two component system three component system.
Extract, raffinate.
Solutropic system.

20. Solvent extraction is a method for separating a
substance from one or more others by using a solvent. It
relies on variations in the solubilities of different
compounds in different substances. In most cases, the
substance to be extracted, which may be a solid, a liquid
or a gas, is dissolved in a liquid, along with other
substances, and a liquid solvent is used for the extraction
— this is sometimes called liquid-liquid extraction.
The technique may also be applied to solid materials that
contain compounds that need to be extracted. This
method is widely used in industry, and in the laboratory
for refining, isolating and purifying a variety of useful
compounds.
Extraction

21. A solvent will be chosen that does not mix with the
compound in which the substance of interest is currently
dissolved, so that, when left undisturbed, they will form two
separate layers, as with oil and water.
It is also important that the compound to be extracted should
have greater solubility in the solvent that has been added,
and that this should not dissolve any unwanted substances
in the original mixture. Once added, the two liquids may be
shaken together for a time then allowed to stand for a while,
so that they separate out.
The choice of solvent to be used will depend on the
chemical and physical properties of all the substances in the
mixture. The process may need to be carried out in several
stages, using different solvents.
Extraction

22. Liquid-liquid extraction 
(also known as 
solvent extraction) involves the
separation of the constituents
 
(solutes) 
of a liquid solution by contact with
another insoluble liquid. Solutes are separated based on their
 
different
solubilities in different liquids. Separation is achieved when the
substances constituting the original solution is transferred from the original
solution to the other liquid solution.
The Figure showed a feed liquid
(the "first" liquid) containing the
desirable compound that is to be
separated together with other
compounds. Then an immiscible
extraction liquid (the "second"
liquid) is added and mixed with the
feed liquid through agitation. The
species
 
re-distribute 
themselves
between the 2 liquid phases.
Agitation of the 2 phases is
continued until equilibrium, and
then agitation is stopped and the
liquids are allowed to settle until
both phases are clear. The 2
phases can then be separated.
Liquid-Liquid Extraction

23. Crystallization
Removal of solids from solutions by super saturating the
solution.
The super saturation may be carried out by cooling, by
vaporizing a portion of the solvent, adiabatic evaporation or by
adding a third component which will reduce the solubility of
solute.


Tank crystallizers, agitated batch crystallizers, continuous
crystallizers, vacuum crystallizers.

24. Evaporation
Removal of major portion of liquid from solution by boiling the
solution.
Major portion of solvents used in extraction are recovered by
evaporation.
Solution is heated in evaporators by using steam in calendrias.The
liquid evaporated is collected at the top ,condensed and collected if
vapor is the useful product.
The solution leaving at the bottom is a thick solution.

25. The solids enter with the solution dose not evaporate because they
do not have sufficient vapor pressure.
Economy, Single effect,multiple effect, once through, circulation
evaporators. Natural convection, forced convection.Climbing film
falling film evaporators,vapor recompression evaporators.
The liquid portion of the feed is divided in to two portions but the
the solid that enters goes only to the bottom stream.
Evaporation, Contd..

26. Super Critical Extraction
•The basic principle of SCE is that when the feed material is
contacted with a supercritical fluid then the volatile substances
will partition into the supercritical phase.
•After the dissolution of soluble material the supercritical fluid
containing the dissolved substances is removed from the feed
material.
•The extracted component is then completely separated from
the SCF by means of a temperature and/or pressure change.
•The SCF is then recompressed to the extraction conditions and
recycled.

27. Advantages of SCE
•Thermally labile compounds can be extracted with minimal
damage as low temperatures can be employed by the
extraction.
•Dissolving power of the SCF is controlled by pressure and/or
temperature.
•SCF is easily recoverable from the extract due to its volatility.
•Non-toxic solvents leave no harmful residue.
•High boiling components are extracted at relatively low
temperatures.
•Separations not possible by more traditional processes can
sometimes be effected.

28. Disadvantages of SCE
•Elevated pressure required
•Compression of solvent requires elaborate recycling
measures to reduce energy costs

•High capital investment for equipment

29. Distillation column
S
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p
in
g

s
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c
t
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n
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in
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s
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30. Fermenter
Solid-liquid
separation
Recovery
Recovery
Cell rupture
Purification
Purification
Cell debris
Cell products
Cells
Supernatant
Extra
cellular
products
Intra
cellular
products
Major process steps in Downstream processing in a typical
Bioprocess Industry

31. •Media preparation-The formation of media to be used
in culturing the process organism during the
development of the inoculum and in the production
fermenter.
•Sterilization_Sterilization of the medium, fermenter and
ancillary equipment,development of Inocula for
industrial fermentations.
•Production of active,pure culture in sufficient quantity
to inoculate the production vessel.
•The growth of the organism in the production
fermenter under optimum conditions for product
formation.
Bio processes

32. •Preparation of reactants-upstream process
•Optimization of conditions in reactor to maximize
process yield
•Recovery of product-down stream process

33. After successful fermentation or enzyme reactions,
desired products must be separated and purified

This final step is commonly known as downstream
processing or bioseparations.
This can account for up to 60 percent of the total
production costs,excluding the cost of raw materials.

34. The fermentation products can be
The cells themselves (biomass)
Components within the fermentation broth
( extra cellular)
Those trapped in cells( intracellular)

Examples of Bio processing Products
Type Products
Cell itself Bakers yeast,single cell protein
Extra cellularAlcohols,organic acids,amino acids
Intracellular Recombinant DNA proteins

35. Bio separation processes make use of many separation
techniques commonly used in chemical process
industries
However, Bio separations have distinct characteristics
which are not common in the traditional separations of
chemical processes.
Some of the unique characteristics of bioseparation
products are
The products are in dilute concentration in aqueous
medium
The products are usually temperature sensitive
There is a great variety of products to be separated
The products can be intracellular,often as insoluble
inclusion bodies

36. The physical and chemical properties of products are
similar to contaminants
Extremely high purity and homogeneity may be needed
for human health care
These characteristics of bioseparation products limit
the use of many traditional separation technologies and
also require the development of new methods

37. •The upstream and down stream processes are mainly
the separation processes.
•The separation processes accounts for 50-90% of the
capital investment
•Separation itself may be main function of an entire
process

38. Common downstream processes used in Bio
processing are

Solid liquid separations – Filtration,centrifugation
Extraction and Leaching
Evaporation

Distillation

Crystallization

Adsorption

Drying

39. Cross flow filtration is different from dead end filtration in which the feed is
passed through a membrane or bed, the solids being trapped in the filter
and the filtrate being released at the other end. Cross-flow filtration gets its
name because the majority of the feed flow travels tangentially across the
surface of the filter, rather than into the filter.
Principle of cross flow filtration
Cross flow filtration

40. Advantages:
•A higher overall liquid removal rate is achieved by the prevention of filter cake
formation
•Process feed remains in the form of a mobile slurry, suitable for further processing
•Solids content of the product slurry may be varied over a wide range
•It is possible to fractionate particles by size
In crossflow filtration, the feed is passed across
the filter membrane (tangentially) at positive
pressure relative to the permeate side. A
proportion of the material which is smaller than
the membrane pore size passes through the
membrane as permeate or filtrate; everything
else is retained on the feed side of the
membrane as retentate.
With crossflow filtration the tangential motion of
the bulk of the fluid across the membrane causes
trapped particles on the filter surface to be
rubbed off. This means that a crossflow filter can
operate continuously at relatively high solids
loads without blinding
Cross flow filtration

41. Crossflow filtration vs Dead-end filtration
　
Filtration modes can be divided by crossflow filtration and dead-end
filtration depending the flow direction on membrane surface.

42. In crossflow filtration, feed moves parallel to the filter medium to
generate shear stress to scour the surface (Fig. 1a). Extra energy is
required to generate crossflow, but cake layer thickness can be
controlled. Pseudo steady-state may exist, where scouring effect and
particle deposition find a balance and cake layer hardly grows. This
filtration mode is particularly effective when feed water carries high
level of foulants such as suspended solids and macromolecules. All
MBR processes and most of wastewater filtrations are adapting
crossflow modes.
In dead-end filtration, no crossflow exits and feed moves toward the
filter medium. All the particles that can be filtered by filter settle on the
filter surface. Since the filtration is not sustainable forever without
removing accumulated solids, backwashing is performed periodically
and/or filter medium is replaced. This filtration mode is particularly
effective when feed water carries low level of foulants. Many surface
water filtrations, pretreatment for seawater RO, and tertiary filtrations
are adapting dead-end modes.

43. •Theory and equipment used in cross flow filtration
•cross flow electro filtration, dual functional filter
•Surface based solid -liquid separations involving a second
liquid, Sirofloc filter.
Assignment
•surface properties, ionic properties and other special
characteristics of substances used in se