Chemical engineering involves designing processes to transform raw materials into useful products through separation processes. Separation processes are based on differences in physical or physicochemical properties between components in a mixture. There are three main types of separation processes: mechanical separations which separate based on size or density differences; diffusional separations which separate dissolved components using mass transfer; and membrane separations which use semipermeable membranes. Common separation unit operations include distillation, crystallization, filtration and centrifugation. The selection of a separation process depends on factors like the composition and properties of the feed and desired products, the required purity levels, and the energy and equipment needs of the process.

1. EP 325 / BEP 3043
Separation Process
LESSON 1
INTRODUCTION TO
SEPARATION PROCESS

3. EMPLOYMENT SECTORS

5. CHEMICAL ENGINEERING ?
Chemical engineering is a discipline influencing numerous areas
of technology. In broad terms, chemical engineers conceive and
design processes to produce, transform and transport materials –
beginning with experimentation in the laboratory followed by
implementation of the technology in full-scale production.

6. Chemical Engineering ???
• Chemical Engineering has to do with industrial
processes in which raw materials are changed
or separated into useful products.

7. Chemical Engineer play a vital role in:
• Production and processing of food products
• Manufacture of fertilizers, insecticides, pesticides, plastics,
synthetic fibers, elastomers drugs, pharmaceuticals, pulp,
paper etc.
• Processing of petroleum crude, production of synthetic fuels,
utilization of biomass, wind, solar, geothermal energy.
• Developing methods and equipments to control the release of
harmful substances to protect the environment.

8. Who is Chemical Engineer ?
• Work scope for Chemical Engineer :
✓ Develop, design and engineering both the complete process and the
equipment used;
✓ Choose the proper raw materials;
✓ Operate the plants efficiently, safely and economically;
✓ Ensure the products meet the requirements set by the customers.
• The professional stature of an engineer depends on skill in
utilizing all sources of information to reach practical solutions
and problems solving.
• Chemical engineers work in four main segments of chemical
process industries i.e. R&D, design, production and sales.

9. What does a Chemical Engineer do?

10. Unit Operations
• In most chemical and biochemical production
processes, the desired products are in mixture with
other components, such as un-converted reactants,
by-products and others.
• Therefore, separation is needed to attain the products
in desired purity and form.
• The term “UNIT OPERATION” has been used for a
time to refer to the various separation processes for
the recovery and purification of products.

11. • Common separation processes/ unit operations
are:
• Separation processes are primarily based on
physical means and some on physico-chemical
means.
Evaporation Distillation
Adsorption Crystallization
Filtration Centrifugation
Spray Drying Membrane Separation

12. General Concept & Characteristics of Separation Processes/
Unit Operations
• Separation of components in a mixture is always
based on the difference in a physical and/or
physicochemical properties among the mixture
components.
• Based on the nature or physical mechanism of
separation, various separation processes can be
classified into:

14. Separation Processes
Mechanical
Separation
Separations based on size and/or density differences of different
components in a mixture, for separation of solid-solid or solid-liquid (e.g.
sieving, filtration and centrifugation)
Diffusional
Separations
(Mass transfer
operations)
Separations based on molecular movement towards a favorable phase,
for separation of dissolved components (e.g. distillation, absorption,
extraction).
(Note: Mass transfer is the transfer of solute molecules from one point to
another or from one phase to another).
Membrane
Separations
Use of a semipermeable membrane to separate molecules with difference
in size or some other properties.

15. Membrane Separation

16. Mechanical Separations
• Mechanical operations that involving particulate solids are:
Size reduction Crushing, grinding
Mixing Solid-solid, solid-liquid
Classification Screening, forth flotation, magnetic
separation, jigging, tabling, electrostatic
separation, wet classification
Solid-fluid
separations
Filtration, sedimentation, centrifugal
separation
Gas-solid separations Dust collection, bag filtration, electrostatic
precipitation
Solid handling Storage feeding, conveying
Size enlargement Pelletization, agglomeration, granulation,
extrusion

17. Factors Affecting the Selection of Separation Process
A. Feed conditions
1. Composition, particularly
concentration of species to be
recovered or separated.
2. Flow rate
3. Temperature
4. Pressure
5. Phase state (solid, liquid, and/or
gas)
B. Product conditions
1. Required purities
2. Temperature
3. Pressure
4. Phase states
C. Property differences that may
be exploited
1. Molecular
2. Thermodynamic
3. Transport
D. Characteristics of separation
operation
1. Ease of scale-up
2. Ease of staging
3. Temperature, pressure and phase-
state requirements
4. Physical size limitations
5. Energy requirements

18. Sieve Diameter
• A sieve diameter is defined as the width of the minimum square aperture
through which the particle will pass.
• A common sizing device associated with this definition is a series of sieves
with square women meshes.
• Two sieve standards, i.e., Tyler Standard and American Society for Testing
and Materials (ASTM) Standard.

20. Prepared by:
Dr. Ng Ching Yin
ngcy@ucsiuniversity.edu.my