Course: CHE442 – SEPARATION PROCESS 1 (3 credits /Compulsory).
Course duration: 15 weeks (45hrs)
As taught in 2011/2012 Session
Lecturers:
1Eletta
O.A.A.
Ph.D. Chemistry (Ilorin), M.Sc. Chemical Engineering (Lagos), B.Sc. Chemical Engineering,
(Lagos)
Email: modeletta@unilorin.edu.ng
Consultation hours: Tuesday 2 -3 pm
2Ajala,
O.E.
M.Sc. Chemical Engineering (Ile-Ife), B.Tech. Chemical Engineering (Ogbomoso).
Email: ajala.oe@unilorin.edu.ng
Consultation hours: Wednesday 2 -3 pm
Developer: Dr O.A.A. Eletta
Location
1: Room 6: Chemical Engineering Building
2: Room 1: Chemical Engineering Building
Course Content
Humidification operations. Drying of solids, evaporation, multiple effect evaporators,
Crystallization, adsorption ion exchange, reverse osmosis, Membrane separation processes.
45h (T) CC: CHE422 C
Course Description
Separation process is defined as that operation which transforms a mixture of substance into
two or more products which differ from one another in composition
The course is designed to introduce students to the physical nature of processes that take place
in industrial units and in particular with determining the factors that influence the rate of
transfer of materials. The factors that affect the operations of the various unit operations are
frequently interdependent in a complex manner and it becomes essential to consider individual
contributions of each of the mechanisms. In a chemical reaction, the final rate of the process
may be governed either by a heat transfer process or by the kinetics and it becomes essential to
decide which of these is the controlling factor. For every operation however, the plant must be
operated in such a way that it does not present an unacceptable hazard to the environment. In
all of these, the control of the effluent generated is of utmost importance in the design of
every plant.
Course Justification: To understand the concept and principles of basic separation processes.
Course Objective (s):
The general objective of the course is for the students to be able at the end of this course to
determine, the best way to handle a separation problem. It could involve, adjustment of
conditions in the reactor or in some cases, there may be a need to use highly sophisticated
separation techniques.
Course Requirements:
All students in chemical engineering are expected to have 75% attendance at lectures besides
writing continuous assessment tests and examination. The 75% attendance qualifies a student
to write the final examination..
Method of grading:
No
Item
1
CA (Quiz, Assignment, Test etc)
2
Examination
3
Total
Score %
30
70
100
Course Delivery Strategies:
The lecture will be delivered through face-to-face method. It is expected that students will
prepare ahead of the class since they have a prepared courseware to guide them. Tutorials will
be handled through interactions in the class after solving examples as a guide.
LECTURES
Week 1: The scope of work, the mode of lecture delivery, the reading texts, the mode of
testing will be introduced. General introduction to separation processes will then be handled.
Objective: To introduce students to the various unit operations employed in the chemical
process industry.
Description: Introduction of the course outline, relevant textbooks and mode of lecture
delivery. The various unit operations will be introduced Chemical Engineering has to do with
the technology of chemical process which is in most cases not easy to define. Unit operations
are a coordinated series of separate operations which are independent of the industries in
which they are used. Unit operations are primarily physical in character. They therefore depend
on the basic laws of physical science.
Study Questions
1. Identify three of the unit operations employed in the chemical process industry and,
describe the working.
Reading list
1. 2Badger, W.L. and Banchero, J.T.; “Introduction to Chemical Engineering”, McGraw Hill
International Book Company, 1 – 26
2. 2Ghosal, S.K., Sanyal, S.K and Datta, S., “Introduction to Chemical Engineering”, Tata
McGraw Hill,
3.
1
4.
1Richardson,
McCabe, W.L., Smith, J.C., and Harriot, P., 2005, “Unit Operations of Chemical
Engineering”, 7th edition, 616 – 642
J.F., Harker, J.H, & Backhurst, J.R., 2005 “ Particle Technology and
Separation Processes” Chemical Engineering volume 2 5th edition Butterworth
Heinemann ; 1 -25
Week 2 -3:
Humidification Operations
Objective: to ascertain the effect of heat and gaseous mass transfer on humidity. Relevance of
humidity chart in determining humidity is to be examined.
Description: Humidification involves the transfer of material between a pure liquid phase and a
fixed gas that is nearly insoluble in the liquid. It is often necessary to prepare air that will have a
known temperature and known humidity by bringing the air in contact with water under such
conditions that the desired humidity is reached. Humidity has been defined as the mass of
vapour carried by a unit mass of vapour – free gas. It depends on only, the partial pressure of
the vapour in the mixture when the total pressure is fixed.
Study Questions
1. Given that the temperature of air in a room is 38 oCand the total absolute pressure is
101.3 kPa, the air is found to contain water vapour with a partial pressure of PA = 3.8
kPa, determine the humidity, the saturation humidity and percentage humidity
2. Flue gas, containing, 5 % O2, 70% N2, 12 % CO2 and 13% H2O at 320o F and atmospheric
pressure,. This gas is to be cooled down by a water spray. Determine the adiabatic
saturation temperature if the water spray enters at 80 o F.
3. Given that the dew point and temperature of the air entering a certain dryer are 25 and
70 o C, determine from the humidity chart, what other additional data the other data
that can be read from the chart.
Reading list
1.
1Badger,
W.L. & Banchero, J.T.; “Introduction to Chemical Engineering”, McGraw Hill
International Book Company, 391 - 425
2. 1McCabe, W.L., Smith, J.C., & Harriot, P., 2005, “Unit Operations of Chemical
Engineering”, 7th edition, 3 – 28
3. 1Ghosal, S.K., Sanyal, S.K & Datta, S., “Introduction to Chemical Engineering”, Tata
McGraw Hill
Week 4 - 5: Drying of solids; evaporation: multiple effect evaporators.
Objective: to ascertain the relevance of drying in the chemical process industry.
Description: This involved the removal of relatively small amount of liquid from a solid material
by means of thermal energy. During drying, mass and heat transfer take place simultaneously.
It is usually the final step in a series of operations and the product is usually ready for
packaging. Solid to be dried may be in different forms; flakes, granules, powder etc.
Evaporation is used for concentration of aqueous solutions, it involves the removal of water
from a solution by boiling in an evaporator and removing the vapour. The heat is supplied
principally to provide the latent heat of vapourisation. We have the single and multiple effect
evaporators.
Study Questions:
1. A 50 kg batch of granular solids containing 25% moisture is to be dried in a tray drier to
12 % moisture by passing a stream of air at 92 oC tangentially across its surface at a
velocity of 1.8 m/s. if the constant rate of drying under these conditions is 0.0008 kg
moisture /m2s, and the critical moisture content is 10%, calculate the drying time. The
surface area available for drying is 1m2.
2. A wet solid is to be dried from 80 to 5% moisture on wet basis, calculate the amount of
moisture to be evaporated per 100 kg of the dried product.
3. A solution of organic colloids is to be concentrated from15 to 50% solids in a vertical –
tube evaporator. The solution has a negligible elevation in boiling point, and the specific
heat of the feed is 0.93 . Saturated steam is available at at 0.8 atm abs, and, the
pressure in the condenser is 100 mm Hg absolute. The feed enters at 15 oC. The overall
heat transfer coefficient is 2000 W/m2./C. The evaporator must evaporate 15,000 kg of
water per hour .what is the steam consumption in kg/hr and the surface area required.
Reading list
1.
2Badger,
W.L. & Banchero, J.T.; “Introduction to Chemical Engineering”, McGraw Hill
International Book Company, 181 – 234; 469 - 519
2. 2Ghosal, S.K., Sanyal, S.K & Datta S., Introduction to Chemical Engineering, Tata
McGrawHill, 202 – 206; 277 – 286
3.
1McCabe,
4.
1Richardson,
W.L., Smith, J.C., & Harriot, P.,
Engineering”, 7th edition, 796 -835
2005, “Unit Operations of Chemical
J.F., Harker, J.H, & Backhurst, J.R., 2005 “ Particle Technology and
Separation Processes” Chemical Engineering volume 2 5th edition Butterworth
Heinemann ; 771 - 823; 901 – 967
Week 6 - 7: Crystallization and Adsorption
Objective: To make the students study unit operations that can be employed in solid liquid
separation processes in which, solid particles are formed within a homogeneous phase.
Description: crystallization usually involves the concentration of solution and cooling of the
solution until the solute concentration becomes greater than the solubility at that temperature.
A t this stage, the solute comes out of the solution in the form of pure crystals. It is important
industrially since the crystals formed are pure. Adsorption on the other hand refers to the
collection and concentration of a particular type of molecules contained in a fluid phase unto a
solid surface. The molecules of the adsorbate come from the liquid phase into the interface
where they remain for a period of time. On reaching the solid surface, the adsorbed molecules
exchange energy with the structural atoms of the surface and if sufficient time is given for
adsorption, the adsorbed molecules arriving at the interface in a given period of time is equal to
the number of molecules leaving the interface to go into the fluid phase.
Study Questions:
1. Given that the molecular weight of sodium carbonate is 106, m.wt of water is 18 and
the m.wt of sodium carbonate decahydrate is 286, determine the yield of crystals
obtained if 15% of the original water in the system evaporates on cooling when a hot
solution containing 2500kg of hot, 25 wt % sodium carbonate solution is cooled to 20 oC
and crystals of sodium carbonate decahydrate are precipitated. You are given the
solubility at 20 oC is 21kg anhydrous /100 kg of total water.
2. If 1 kg of activated carbon is used to adsorb benzene from 2.5 m 3 of an air – benzene
vapour mixture containing 5 % of benzene by volume at 20oC. Benzene is desorbed
from the activated carbon by superheated steam at 200 o C. Given that the adsorption
capacity of activated carbon at 20 oC is 382 g and at 200o C is 69.6 g of benzene per 1 kg
of activated carbon, calculate the benzene content of the of the air after the adsorption
process, and the degree of utilization of activated carbon in the adsorption of benzene.
Reading list
1.
2Badger,
W.L. & Banchero, J.T.; “Introduction to Chemical Engineering”, McGraw Hill
International Book Company,
2. 2Ghosal S.K., Sanyal S.K & Datta S., “Introduction to Chemical Engineering”, Tata
McGraw Hill, 287 - 303
3.
1McCabe
4.
1Richardson
W.L., Smith J.C., and Harriot P., 2005, “Unit Operations of Chemical
Engineering”, 7th edition, 836 – 881; 929 - 964
J.F., Harker J.H, and Backhurst J.R., 2005 “ Particle Technology and
Separation Processes” Chemical Engineering volume 2 5th edition Butterworth
Heinemann ; 827 – 897; 970 - 1049
Week 8: Mid Semester Test
Week 9: solution to continuous assessment questions. Revision of work done so far and
tutorials.
Objective: To determine the extent to which the students have been able to understand work
done so far and get the student involved in the practical area of lecture so far.
Description: Solution to the test done by the student in the previous week will be done after
which, the students will be actively involved in the proffering solutions to questions prepared
to the tutorial class.
Reading List:
1. 2Badger, W.L. & Banchero, J.T.; “Introduction to Chemical Engineering”, McGraw Hill
International Book Company, 1 – 26
2. 2Ghosa,l S.K., Sanyal S.K & Datta S., 2006, “Introduction to Chemical Engineering”, Tata
McGraw Hill,
3.
1McCabe,
4.
1Richardson,
W.L., Smith, J.C., & Harriot P., 2005, “Unit Operations of Chemical
Engineering”, 7th edition, 616 – 642
J.F., Harker, J.H, & Backhurst, J.R., 2005 “ Particle Technology and
Separation Processes” Chemical Engineering vol(2) 5th edition Butterworth Heinemann
; 1 -25
Week 10 - 11: Ion exchange and Reverse Osmosis
Objective: To relate mass transfer operations to its application in ion exchange and Reverse
osmosis operations.
Description: Ion exchange which is a process in which solid particles containing exchangeable
cations or anions are contacted with an electrolyte solution to change the composition of the
solution. It is employed in the removal of inorganic wastes from waste water. We could have
the mixed bed unit or the two- bed deionizer. Major applications are seen in the softening of
water and, in the recovery of metals from dilute solutions.
The pressure driven transport of water from a solution through a membrane is referred to as
reverse osmosis. It is used in industrial processes for the concentration of low molecular
weight solutes and especially for the demineralization of water. Reverse osmosis is a major
process employed in the purification of saline water. Here pressure is applied to an aqueous
salt solution to cause portable water to flow through a semi permeable membrane in osmotic
flow a direction opposite to the normal
Study Questions:
1. Differentiate between osmosis and reverse osmosis. Give emphasis on water treatment.
2. Discuss the application of Ion exchange in separation
Reading List:
1. 2Ghosal S.K., Sanyal S.K & Datta S., 2006, “Introduction to Chemical Engineering”, Tata
McGraw Hill, 540 – 543
2.
1McCabe,W.L.,
Smith J.C., & Harriot P.,
2005, “ Unit Operations of Chemical
Engineering”, 7th edition 864 -881
3.
1Richardson
J.F., Harker
J.H, & Backhurst J.R.,
2005 “ Particle Technology and
Separation Processes” Chemical Engineering Vol (2),
5th edition
Butterworth
Heinemann ; 452 - 464
Week 12 – 13: Membrane Separation Processes:
Objective: To discuss the separation of liquid or gaseous mixtures (crucial economic operation)
by employing semi permeable membranes.
Description: Industrial membrane processes maybe classified according to the size range of
materials they are to separate and the driving force used in separation. It involves pressure
driven processes. For this process, the membranes employed allow one or more constituents of
the mixture to pass through more readily than the others. The membranes employed are
usually polymeric materials.
Study Questions:
1. Differentiate between osmosis and reverse osmosis. Give emphasis on water treatment.
2. Discuss the application of Ion exchange in separation
Reading List:
1. If a membrane has a selectivity of 8 for air separation, what is the maximum oxygen
concentration that can be obtained for a single – stage, device.
2. Laboratory tests of a membrane for hydrogen/methane separation gave a permeate
composition of 80%, hydrogen and a residue of 42% hydrogen when the feed had 50%
hydrogen and the feed and permeate absolute pressure was 100 and 15 ibf/in2. The permeate
flow was 20% of the feed flow. What is the membrane selectivity.
1.
1McCabe,
W.L., Smith J.C., & Harriot P.,
2005,
“Unit Operations of Chemical
Engineering”, 7th edition, Ghosal S.K., Sanyal S.K & Datta S., “ Introduction to Chemical
Engineering”, Tata McGraw Hill, 882 - 928
2.
1Richardson
J.F., Harker J.H, & Backhurst J.R., 2005 “ Particle Technology and Separation
Processes” Chemical Engineering volume 2 5th edition Butterworth Heinemann ; 437 –
475
Week 14: General revision and tutorials
Week 15: Examination