1. Separation Process

2. 1
Separation Methods

3. Separation Methods 1. Separation Methods
The separation of chemical mixtures into their constituents has been practiced for millennia.
Perfume
Metal
Liquor
Salt
Separation Process

4. A chemical process is conducted in various manner.
1.1 Industrial Chemical Processes
1. Separation Methods
A chemical process is conducted in various manner.
Feed
Operating Mode
Operation
○ Natural raw material
○ Plant or animal matter
○ Chemical intermediate
○ Chemicals of commerce
○ Waste products
○ Batchwise
○ Continuous
○ Semicontinuous
○ Key operations
- Chemical reactions
- Separations
○ Auxiliary operations
- Phase separations
- Heat addition
- Heat removal
- Shaft-work addition
- Shaft-work removal
- Mixing
- Dividing
- Solids agglomeration
- Size reduction
- etc.
Separation Process

5. 1.1 Industrial Chemical Processes
1. Separation Methods
Block-flow diagrams are used to represent chemical processes.
Block-flow diagrams indicate, by square or rectangular blocks,
chemical reaction and separation steps and, by connecting lines,
the major process streams that flow from one processing step to another.
Separation Process

6. 1.1 Industrial Chemical Processes
1. Separation Methods
Hypothetical
Side reaction과
Feed의 Impurity는
공정을 복잡하게 만드는
주요 원인이다.
따라서
분리공정은 실제 산업 공정에서 매우 중요한 역할을 담당한다.
Industrial
Separation Process

7. WHY 1.2 Mechanism of Separation 1. Separation Methods Spontaneous
Not spontaneous
Mixing
Separation
WHY
Separation Process

8. General Separation Techniques
1.2 Mechanism of Separation
1. Separation Methods
General Separation Techniques
Separation Process

9. General Separation Techniques
1.2 Mechanism of Separation
1. Separation Methods
General Separation Techniques
(a) Separation by phase creation
- Energy를 이용하여 새로운 상을 만드는 방법
- 증류, 결정화
(b) Separation by phase addition
- 제 3의 물질(Mass separating agent)를 이용하여 분리
- 용제 추출
Separation Process

10. 1.2 Mechanism of Separation
1. Separation Methods
(c) Separation by barrier
- Barrier(Membrane) 등을 이용하여 분리
- 막 분리
(d) Separation by solid agent
- 흡착 성질이 뛰어난 고체를 활용
- 숯, 실리카 겔
(e) Separation by force field or gradient
- 중력, 원심력, 전자기장 등을 활용
- 원심분리기
Separation Process

11. 특정 화학 물질의 물질 전달 속도를 다른 물질에 비해 상대적으로 향상시킴으로써
1.2 Mechanism of Separation
1. Separation Methods
위 공정들은 공통적으로
특정 화학 물질의 물질 전달 속도를 다른 물질에 비해 상대적으로 향상시킴으로써
분리를 수행한다.
물질 전달에 의해 지배
열역학적 평형에 의해 제한
분리의 속도
분리되는 양 2장 3장
Separation Process

12. 1.2 Mechanism of Separation
1. Separation Methods
원료 속 물질들이 분리되는 양은
존재하는 다른 상들의 분자, 열역학, 이동 물성의 차이를 어떻게 이용하느냐에 따라 다르다.
중요한 물성으로는 다음과 같은 것들이 있다.
Molecular Properties
Thermodynamic and Transport Properties
Molecular weight
van der Waals volume
van der Waals area
Molecular shape (acentric factor)
Dipole moment
Polarizability
Dielectric constant
Electric charge
Radius of gyration
Vapor pressure
Solubility
Adsorptivity
Diffusivity
Handbooks
Journals
Electronic Databases
Commercial Process Simulators
Separation Process

13. (Energy-Separating Agent)
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Partial Condensation or Vaporization
○ Heat transfer V
V/L
ESA
(Energy-Separating Agent) L
Ex) Recovery of and from ammonia
Separation Process

14. Ex) Recovery of water from sea water
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Flash Vaporization
○ Pressure reduction V L L
Ex) Recovery of water from sea water
Separation Process

15. Ex) Purification of styrene
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Distillation
○ Heat transfer(ESA) or
sometimes work transfer.
○ When the volatility
difference among species
are not sufficiently large.
○ Most widely used industrial
separation technique.
○ Multiple contact between
counter-current flow of V/L
in trays(stages).
Condenser L
Reflux
Rectifying section
V/L
Stripping section
Reboil
Reboiler L
Ex) Purification of styrene
Separation Process

16. 1.3 Separation by Phase Addition or Creation 1. Separation Methods
Distillation Tower
Separation Process

17. (Mass-Separating Agent)
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Extractive Distillation
○ Liquid solvent(MSA) and
Heat transfer(ESA)
○ When the volatility
difference among species
are so small. (More than
100 trays are required)
○ MSA is used to increase
volatility difference (to
reduce the number of trays)
○ Minimizing MSA loss
(recycling) L
MSA
(Mass-Separating Agent)
V/L L
Ex) Separation of acetone and methanol
Separation Process

18. (Mass-Separating Agent)
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Reboiled Absorption
○ Liquid absorbent(MSA)
and Heat transfer(ESA)
○ When condensation of
vapor is not easily
accomplished
○ Removal of ethane and
lower molecular
hydrocarbons from LPG V
MSA
(Mass-Separating Agent)
(L)
V/L L
Ex) Removal of ethane and lower molecular weight hydrocarbons for LPG production
Separation Process

19. (Mass-Separating Agent)
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Absorption
○ Liquid absorbent(MSA) V
MSA
(Mass-Separating Agent)
(L) V L
Ex) Separation of carbon dioxide from combustion products by absorption with aqueous solutions of an ethanolamine
Separation Process

20. (Mass-Separating Agent)
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Stripping
○ Stripping agent(MSA) V L
MSA
(Mass-Separating Agent)
(V) L
Ex) Stream stripping of naphtha, kerosene, and gas oil side cuts from crude distillation unit to remove light ends
Separation Process

21. (Mass-Separating Agent) (Mass-Separating Agent)
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Refluxed Stripping (Steam Distillation)
○ Stripping vapor(MSA) and
heat transfer(ESA)
L/V
MSA
(Mass-Separating Agent)
V/L
MSA
(Mass-Separating Agent) L
Ex) Separation of products from delayed coking
Separation Process

22. Ex) Recovery of amine absorbent
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Reboiled Stripping
○ Heat transfer V L L
Ex) Recovery of amine absorbent
Separation Process

23. (Mass-Separating Agent) (Mass-Separating Agent)
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Azeotropic Distillation
○ Liquid entrainer(MSA)
and heat transfer(ESA)
Recycle MSA
(Mass-Separating Agent) L
Makeup MSA
(Mass-Separating Agent)
V/L L
Ex) Separation of acetic acid from water using n-butylacetate as an entrainer to form an azeotrope with water
Separation Process

24. (Mass-Separating Agent)
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Liquid-Liquid Extraction
○ Liquid solvent(MSA) L1
MSA
(Mass-Separating Agent)
(L) L1 L2
Ex) Recovery of aromatics
Separation Process

25. (Mass-Separating Agent) (Mass-Separating Agent)
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Liquid-Liquid Extraction (Two Solvent)
○ Two solvent L
MSA 1
(Mass-Separating Agent)
(L) L
MSA 2
(Mass-Separating Agent)
(L) L
Ex) Use of propane and cresylic acid as solvents to separate paraffins from aromatics and naphthenes
Separation Process

26. 1.3 Separation by Phase Addition or Creation 1. Separation Methods
Drying
○ Heat transfer(ESA) V
(V)
L/(S) S
Ex) Removal of water from polyvinylchloride with hot air in a fluid-bed dryer
Separation Process

27. Ex) Evaporation of water from a solution of urea and water
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Evaporation
○ Heat transfer(ESA) V L L
Ex) Evaporation of water from a solution of urea and water
Separation Process

28. Ex) Crystallization of p-xylene from a mixture with m-xylene
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Crystallization
○ Heat transfer(ESA)
(V) L L S
Ex) Crystallization of p-xylene from a mixture with m-xylene
Separation Process

29. Ex) Recovery of phthalic anhydride from noncondensible gas
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Desublimation
○ Heat transfer(ESA) V V S
Ex) Recovery of phthalic anhydride from noncondensible gas
Separation Process

30. (Mass-Separating Agent)
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Leaching (Liquid-Solid Extraction)
○ Liquid solvent S L
MSA
(Mass-Separating Agent)
(L) S
Ex) Extraction of sucrose from sugar beets with hot water
Separation Process

31. (Mass-Separating Agent)
1.3 Separation by Phase Addition or Creation
1. Separation Methods
Foam Fractionation
○ Gas bubbles(MSA) V
L (foam) L
MSA
(Mass-Separating Agent)
(V) L
Ex) Recovery of detergents from waste solutions
Separation Process

32. 1.4 Separation by Barrier 1. Separation Methods
The use of microporous and nonporous membranes
as semipermeable barriers for difficult and highly selective separations
is rapidly gaining adherents.
Separation is effected by differing rates of diffusion through the pores.
Separation occurs because of differences in both solubility in the membrane
and rate of diffusion through the membrane.
Microporous membranes
Nonporous membranes
Separation Process

33. 1.4 Separation by Barrier 1. Separation Methods Osmosis
○ Separating agent
- Nonporous membrane
Solvent
Separation Process

34. Ex) Desalinization of sea water
1.4 Separation by Barrier
1. Separation Methods
Reverse Osmosis
○ Separating agent
- Nonporous membrane
with pressure gradient L L
Solvent L
Ex) Desalinization of sea water
Separation Process

35. Ex) Recovery of caustic from hemicellulose
1.4 Separation by Barrier
1. Separation Methods
Dialysis
○ Separating agent
- Porous membrane
with pressure gradient L L
Small solute L
Ex) Recovery of caustic from hemicellulose
Separation Process

36. Ex) Removal of bacteria from drinking water
1.4 Separation by Barrier
1. Separation Methods
Microfiltration
○ Separating agent
- Microporous membrane
with pressure gradient
○ Particle size
~ 10 μm L L
Solvent L
Ex) Removal of bacteria from drinking water
Separation Process

37. Ex) Separation of whey from cheese
1.4 Separation by Barrier
1. Separation Methods
Ultrafiltration
○ Separating agent
- Microporous membrane
with pressure gradient
○ Particle size
- 1 ~ 20 nm L L
Solvent L
Ex) Separation of whey from cheese
Separation Process

38. Ex) Separation of azeotropic mixtures
1.4 Separation by Barrier
1. Separation Methods
Pervaporation
○ Separating agent
- Nonporous membrane
with pressure gradient L L
Gas
(Evaporation) V
Ex) Separation of azeotropic mixtures
Separation Process

39. Ex) Hydrogen enrichment
1.4 Separation by Barrier
1. Separation Methods
Gas Permeation
○ Separating agent
- Nonporous membrane
with pressure gradient V
Gas mixture V
Gas V
Ex) Hydrogen enrichment
Separation Process

40. Ex) Removal of hydrogen sulfide
1.4 Separation by Barrier
1. Separation Methods
Liquid Membrane
○ Separating agent
- Liquid membrane
with pressure gradient
V/L
V/L
Liquid layer
V/L
Ex) Removal of hydrogen sulfide
Separation Process

41. 1.4 Separation by Barrier 1. Separation Methods Liquid Membrane
Separation Process

42. 1.5 Separation by Solid Agent
1. Separation Methods
Solid Mass Separating Agent
Granular Material
Packing Material
Acting as an inert support for a thin layer of absorbent
Entering directly into the separation operation by selective adsorption of, or chemical reaction with, certain species in the feed mixture
The active separating agent eventually becomes saturated with solute
and must be regenerated or replaced periodically.
Separation Process

43. 1.5 Separation by Solid Agent
1. Separation Methods
Adsorption
Regeneration
Adsorbent
Activated carbon
Aluminum oxide
Silica gel
Zeolite adsorbents(Molecular sieve)
Regeneration methods
Thermal Swing(TSA)
Pressure Swing(PSA)
Inert purge stripping
Displacement desorption
Hydrogen PSA units
Separation Process

44. Ex) Purification of p-xylene
1.5 Separation by Solid Agent
1. Separation Methods
Adsorption
○ Separating agent
- Solid adsorbent
V/L
V/L
V/L
Ex) Purification of p-xylene
Separation Process

45. Ex) Separation of xylene isomers and ethylbenzene
1.5 Separation by Solid Agent
1. Separation Methods
Chromatography
○ Separating agent
- Solid adsorbent or
liquid adsorbent
on a solid support
V/L
V/L
Ex) Separation of xylene isomers and ethylbenzene
Separation Process

46. Ex) Demineralization of water
1.5 Separation by Solid Agent
1. Separation Methods
Ion Exchange
○ Separating agent
- Resin with ion-active sites
○ Ion exchange resembles
adsorption but it involves
chemical reaction L L L
Ex) Demineralization of water
Separation Process

47. 1.6 Separation by External Field or Gradient 1. Separation Methods
Separation Process

48. 1.6 Separation by External Field or Gradient 1. Separation Methods
Centrifugation
Separation Process

49. 1.6 Separation by External Field or Gradient 1. Separation Methods
Electrodialysis
Separation Process

50. 1.6 Separation by External Field or Gradient 1. Separation Methods
Electrophoresis
Using different migration velocities of charged colloidal
or suspended species in a electric field
○ Application
- Biochemicals
Separation Process

51. Field Flow Fractionation (FFF)
1.6 Separation by External Field or Gradient
1. Separation Methods
Field Flow Fractionation (FFF)
○ Micromolecular and
colloidal materials
Separation Process

52. 1. Separation Methods 1.7 Component Recoveries and Product Purities
No reaction
Continuous and steady state
Separation operations are subject to the conversion of mass.
i : 1 ~ C  Number of Components
p : 1~ N  Product phases
F : feed
Separation Process

53. Example – Hydrocarbon Recovery Plant
1.7 Component Recoveries and Product Purities
1. Separation Methods
Example – Hydrocarbon Recovery Plant
Separation Process

54. 1. Separation Methods 1.7 Component Recoveries and Product Purities
Split Fraction
i : component
k : separator
(F) : feed
: first product (ex: top product)
: second product (ex : bottom product)
Split Ratio
0 < SF < 1
0 < SR ~ very large value
SF may be a better quantitative measure of
degree of separation than SR
Separation Process

55. 1. Separation Methods Material Balance
1.7 Component Recoveries and Product Purities
1. Separation Methods
Material Balance
Separation Process

56. Split Fraction / Split Ratio / Percent Recovery
1.7 Component Recoveries and Product Purities
1. Separation Methods
Split Fraction / Split Ratio / Percent Recovery
Flow rate in the desired stream / Feed X 100
Good separation
SR is not sharp ( )
→ Significant in product
SF > 0.95 → Light key
SF < 0.05 → Heavy key
Separation Process

57. Product Specification
1.7 Component Recoveries and Product Purities
1. Separation Methods
Product Purity
Product Specification
Separation Process

58. 1.8 Separation Power 1. Separation Methods Separation Power
C is some measure of composition such as
mole fraction, mass fraction,
or concentration in moles or mass per unit volume.
Separation Process

59. Selection of a best separation processes
1.9 Selection of Feasible Separation Processes
1. Separation Methods
Selection of a best separation processes
○ Selection among a number of feasible candidates
○ Combination of operations may be considered (Hybrid process)
Important factors that influence the selection of feasible separation operations
○ Feed conditions
○ Product conditions
○ Property differences
○ Characteristics of separation
Separation Process

60. 1.9 Selection of Feasible Separation Processes 1. Separation Methods
○ The most important
feed conditions are
composition and flow rate.
○ The other conditions
can be altered by
pumps, compressors, and
heat exchangers.
Separation Process

61. 1.9 Selection of Feasible Separation Processes 1. Separation Methods
Keller’s Correlation
○ The cost of recovering and
purifying a chemical
contained in a mixture can
depend strongly on
the concentration of that
chemical in the feed mixture.
○ The more
dilute the chemical is,
the higher
its price is.
Separation Process

62. 1.9 Selection of Feasible Separation Processes 1. Separation Methods
Technological and Use Maturity of Separation Processes
Expensive
Separation by barrier
Separation by solid agent
Creation of addition of second phase
Cheap
Separation Process

63. 1.9 Selection of Feasible Separation Processes 1. Separation Methods
Ease of Scale-up
200%
150%
Separation Process