Template-based Authoring Knowledge Systems Laboratory Stanford.
Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
-
Upload
maureen-direro -
Category
Documents
-
view
215 -
download
0
Transcript of Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
1/38
FACULTY OF ENGINEERING AND THE BUILT ENVIRONMENT
DEPARTMENT OF CHEMICAL AND METALLURGICAL ENGINEERING
NAME OF COURSE:
CHEMICAL ENGINEERING PLANT (IIIA)
NQF
LEVEL
NQF
CREDIT
S
QUALIFICATION & SAQA IDCOURSE
CODE
Diploma In CHEMICALENGINEERINGSAQA ID No.: NLRD49744..
(CMP33AT)
COMPILED BY : Mr M. Mosesane 2009
REVISED BY : Mr V. Hlongwane 2010
STUDENT LABORATORY
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
2/38
PAGE 2OF 42
COPYRIGHT : Tshwane University of Technology
Private Bag X680
PRETORIA
0001
Printed and distributed by :
FACULTY OF ENGINEERING AND
BUILT ENVIRONMENT
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
3/38
ORGANISATIONAL COMPONENT CONTENTS:
1. Welcome.....................................................................................................................5
2. LABORATORY Staff...................................................................................................6
2.1 Contact Details......................................................................................................6
2.2 Staff availability.....................................................................................................6
3. Requirements, resources and recommended material.............................................7
3.1 Requirements for the course.................................................................................8
4. Code of conduct.......................................................................................................10
5 Attendance............................................................................................................14
5.1 LABORATORY, HEALTH & SAFETY RULES AND REGULATIONS...............14
BASIC RULES...........................................................................................................14
5.2 Responsibilities of students................................................................................14
6. Assessment..............................................................................................................15
6.1 Assessment methods and criteria......................................................................15
6.2 Assessment rules................................................................................................15
6.3 Marking system .................................................................................................15
6.4 predicate/Year mark...........................................................................................16
PAGE 3OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
4/38
6.5 Moderation ........................................................................................................17
6.6 Promotion requirements.....................................................................................17
7. laboratory course content and schedule..................................................................17
7.1 schedule of laboratory sessions and assignments.............................................17
7.2 Learning outcomes and assessment criteria.....................................................19
7.3 Generic outcomes and critical cross-field outcomes.........................................21
8. Glossary of terms ....................................................................................................21
9. Assessment Records ..............................................................................................21
10 Example of a practical report...............................................................................22
11. Appendices ...........................................................................................................26
11.1 Flocculation and coagulation.............................................................................26
11.2 sedimentation experiment.....................................................................................29
Up = true particles hindered velocity (m/s).................................................31
12. Example of a practical report.................................................................35
PAGE 4OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
5/38
SECTION A ORGANISATIONAL COMPONENT
1. WELCOME
Welcome to laboratory session of Chemical Engineering Plant IIIA. This part
of the course provides an introduction and represents advanced knowledge
in unity operation and is offered via experimental work, problem-based
work or project-based work over 8 weeks. The course is structured in such
a way as to master theoretical concepts and principles and various
practical skills to provide a sound foundation for the study of Distillation,
Absorption and Drying to complement the major courses in the qualification
and pave the way for more advanced learning in B-Tech in Chemical
engineering. We trust you will enjoy the course, and find it interesting and
informative.
PAGE 5OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
6/38
2. LABORATORY STAFF
2.1 CONTACT DETAILS
NAMECAMPU
S
ROOM
NO
TEL NO
E-MAIL
CONSULTA
TION
TIMES
ACADEMIC
FUNCTION
Dr R.
MbayaPretoria
(012) 382 3513
.za
Lecturer
Mr M.J
MosesanePretoria
B2
R127
(012) 382 4655
mosesanejm@t
ut.ac.za
08H00
16H00
Technologis
t
Mentors
2.2 STAFF AVAILABILITY
PAGE 6OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
7/38
If, after attending class and making every effort from your side to master
content, you still have problems with understanding key concepts or
principles or their application, lecturers are available for consultation.
To consult your lecturer, make an appointment by calling his office or see/
call the secretary at (012) 382 3597/3514 for an appointment.
To consult your technologist, make an appointment by calling his office at (
012) 382 4655 or call the secretary at (012) 382 3514.
3. REQUIREMENTS, RESOURCES AND RECOMMENDED
MATERIAL.
PAGE 7OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
8/38
3.1 REQUIREMENTS FOR THE COURSE
3.1.1 PRESCRIBED RESOURCES
The following tables indicate what literature and other resources are
essential for successful completion of this course. You are strongly advised
to acquire all the prescribed resources.
PRESCRIBED RESOURCES
CATEGORY DESCRIPTION WHERE TO FIND COST LEVY
CALCULATOR Scientific Bookstore
COMPUTER Computer lab
HARDWARE Laboratory
Journal/Notebook ( not a
page or exam pad )
SOFTWARE
PAGE 8OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
9/38
EQUIPMENT SedimentationStudy Kit and
Jar test
equipment
COMPONENTS
3.1.2 RECOMMENDED RESOURCES
The following recommend resources will enhance your understanding andknowledge in this course, and you are encouraged to use the following
additional resources.
RECOMMENDED RESOURCES
CATEGORY AUTHOR NAME PUBLISHE
R
ISBN NO
BOOKS
MANUALS Laboratory
Manual
PAGE 9OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
10/38
GUIDES
RECOMMENDED ELECTRONIC MATERIAL & WEBSITES
VIDEO
CD
DVD
WEBSITES
4. CODE OF CONDUCT
Safety
Laboratory safety is the top priority and this requires all people in the lab to
be observing safe practices at all times!
PAGE 10OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
11/38
Safety glasses must always be worn by everyone in the laboratory.
Make sure you understand how the experimental apparatus works and
what all
of the adjustments do before you attempt to operate it.
Be sure you have asked, and received an answer, from the Technician
about any possible hazards related to your experiment before attempting
to operate it.
Care must be used in the handling of chemicals to avoid spills and to
avoid contact with the skin.
B. Laboratory Format and Procedures
1. Organization of Student Groups and Laboratory Projects
Students will organize into groups of five persons. Each group is to perform
three projects during the semester. (A roster of the groups and a schedule
of projects will be supplied separately.)
A group leader, who is in charge of directing the work for the lab,
should be selected by, and from among, the members of the group.
(This responsibility should rotate among the members.) All group
members must be prepared for the laboratory and contribute equally
to the laboratory work and preparation of the reports. However, the
group leader is in charge of assigning and coordinating tasks for the
laboratory period and maintaining the group notebook. He or she is
ultimately responsible for making sure that everything is done to
ensure a successful experiment.
2. Laboratory Session 1
At the beginning of the first session for a given experiment, a
paragraph describing the experimental plan and procedure
should be submitted to the Technician who is in charge at
PAGE 11OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
12/38
that time. A discussion between the Technician and the
students will take place to ensure that students have an
accurate plan of action.
3. Laboratory Session 2
The Technical report should be submitted to the Technician in charge of the
experiment. A summary discussion of the report with the instructor will be
conducted in the laboratory.
4. Session 3
The laboratory will be open to gather additional data if needed. The
lecturer will be available for consultations during the first hour of the
laboratory period. During this session examination of the experimental
apparatus for the next assigned project should be performed by each
group.
5. Final Technical Report .
The final Technical report is due at the beginning of the next scheduled
laboratory period following Session 3. There are no exceptions to this
deadline. The reports are to be submitted to one of the department
secretaries in the Chemical Engineering office or to the Technician. During
the week following the day on which the final report was submitted, the
group should schedule a meeting with the lecturer for the discussion of the
written report. Each member of the group should be prepared to defend
and/or discuss any part of the final report.
6. Laboratory Notebook
Part of the purpose of the chemical engineering laboratories is to learn
good laboratory and research practices. An important aspect of this is
safety. Another important aspect is record-keeping and documentation. In
industry you will find that all experiments have to be carefully recorded in
an official laboratory notebook and signed by the investigator on a daily
basis. To help foster these professional practices, each group is required to
PAGE 12OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
13/38
keep a laboratory notebook documenting the group's work. In the notebook
should be kept a neat, labeled and dated record of all work associated with
the experiment, including a copy of the precis, all raw data, the settings on
the experimental controls, any problems encountered in the experiment
and what was done to fix them and why, all calculations, a copy of your
progress report, etc. The laboratory notebooks will be handed in at the endof the semester and will contribute to the laboratory participation portion of
your grade.
7. Student Responsibilities in the Laboratory
Condition of Working Area. Students are responsible for the condition
of their working area at the end of each laboratory period.
All power to the equipment and instruments should
be turned off, and steam and cooling water flowsshould be shut off.
Glassware used should be cleaned and dried.
Any equipment or instrumentation malfunctionsshould be reported promptly to the Technician orassistants.
Checkout before Leaving Laboratory. The students must have their
notebooks initialed by a Technician prior to leaving at the end of the
laboratory period. At that time the Technician will check the working area
and take information about any equipment or instrumentation problems.
8. Grading/Marking
Report grading is done by the lecturers who are in charge of a given
experiment. This grade will be based on the written report, the oral
defense and other pertinent factors (e.g., if you are totally unprepared to
do an experiment, you will be docked.) Grades for this course will be
determined by the grades on the three experiments as well as your
laboratory participation. The laboratory participation portion of your gradein will include how well you followed laboratory safety guidelines (did you
wear safety glasses at all times in the lab? did you follow the special safety
precautions required for each experiment?), attendance, tardiness,
participation, professionalism, how effective a group leader you were, and
the quality of your laboratory notebook. Both laboratory instructors and
teaching assistants will contribute towards this portion of your grade.
PAGE 13OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
14/38
5 ATTENDANCE
Regular attendance of the chemical engineering plant (IIIA) lectures is of
primary importance. It is the learners responsibility to sign the register
each week. A minimum attendance of 75% is mandatory for all courses
including practical In a 30 week year, 8 classes that have not been
attended and for which you have not furnished a valid doctors letter or
other proof of extenuating circumstances, amounts to 25% absenteeism.
This level of absenteeism will lead to exclusion from the final moderation at
the end of the year, which means that you will fail the course and will have
to repeat it the following year.
5.1 LABORATORY, HEALTH & SAFETY RULES AND REGULATIONS
5.1.1. LABORATORY RULES
BASIC RULES
Always wear a laboratory coat in the laboratory.
Do not wear open shoes in the laboratory.
Do not eat or drink in the laboratory.
No horse-playing in the laboratory.
Always ask the technician if you are not sure of anything.
5.2 RESPONSIBILITIES OF STUDENTS
It is your responsibility to make a success of learning in this course. To this
end you are encouraged to attend class, write practical reports and hand in
your assignments/projects on the set due dates.
PAGE 14OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
15/38
SECTION B LEARNING COMPONENT
6. ASSESSMENT
6.1 ASSESSMENT METHODS AND CRITERIA
Assessment of this laboratory course will include experimental work,problem-based work, Project-based works and assignments, as indicated in
the schedule under section 2.2. The purpose of assessment is to determine
whether you have achieved the learning outcomes. The various assessment
methods therefore will focus on criteria that will enable the lecturer(s) to
determine whether you have achieved the learning outcomes and
mastered the required skills. The assessment criteria relevant to each
learning outcome are detailed in section 2.
6.2 ASSESSMENT RULES
The general rules of TUT regarding assessment apply. You are advised to
familiarise yourself with these rules, as they are applied stringently.
6.3 MARKING SYSTEM
Subject Max Mark Actual Mark
1. Title Page 1
2. Abstract 6
PAGE 15OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
16/38
3. Introduction 2
4. Theoretical Background 3
5. Procedure 2
6. Results 6
7. Discussion of Results 10
8. Conclusion and
Recommendations
4
9. Literature Cited 1
10. Nomenclature 1
11. Organization and Neatness 2
Appendix
A1 Raw Data 2
A2 Data analysis and Sample
Calculations
10
TOTAL 50
6.4 PREDICATE/YEAR MARK
(Indicate how the laboratory mark will be calculated and any rules you have
in this regard. Also indicate the percentage it contributes to the
predicate/year mark. Distinguish between semester modules and year
subjects) Predicate marks are put on the faculty notice boards. If you
PAGE 16OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
17/38
have queries about your mark, you must immediately consult your
course lecturer (contact details are given above), before predicate
day. Once the predicate mark is entered on TUTs mainframe computer,
the mark cannot be changed.
6.5 MODERATION
The lecturer of the subject will be responsible to moderate all practical
report.
6.6 PROMOTION REQUIREMENTS
The leaner has to obtain the minimum of 50% in the practical report in
order to pass.
7. LABORATORY COURSE CONTENT AND SCHEDULE
This course comprises of an experimental component, problem-based
component and a project-based component. Your mastery of the required
skills is assessed at regular intervals. More importantly, the application of
theory is assessed through problem-based- or project-based assignments
or projects.
The following outline provides an overview of the content to be covered in
this course and the ways in which your progress will be assessed.
7.1 SCHEDULE OF LABORATORY SESSIONS AND ASSIGNMENTS
PAGE 17OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
18/38
DURATION THEME
EXPERIMENTAL/
PROBLEM-
BASED/
PROJECT-BASED
COMPLETION DATE*
Week 1-4SEDIMENTATION
(Learning Outcome 1)
To studydifferent settlingregimes and todetermine the
relationshipbetweenconcentrationand settlingvelocity.
To study theconcepts offlocculation andanti-flocculationand apply themto thickener
operation anddesign.
To be able tosize thickenersbased onparticle sizes,fluid viscosities,and desiredconsistencies.
SEDIMENTATION
Week 5-8Coagulation andflocculation
(Learning Outcomes 2)
To conduct jartest on a natural
Coagulation andflocculation
PAGE 18OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
19/38
surface water inorder toestimate anoptimumdosage ofaluminium
sulphate orferric sulphatefor the removalof suspendedmatter orcolour.
To observe therate of flocformation andsedimentation.
7.2 LEARNING OUTCOMES AND ASSESSMENT CRITERIA
The following tables clearly indicate what you have to achieve (the learning
outcomes) and how you will be assessed (assessment criteria) to determine
whether you have achieved the required knowledge and competences:
PAGE 19OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
20/38
PAGE 20OF 42
LEARNING OUTCOME 1:
SEDIMENTATION, COAGULATION AND FLOCCULATION
Assessment criteria Assessment method
Report writing skills
Data collection and interpretation
Task performance
Written report(marking the report)
Questions and Answers
Observation
LEARNING OUTCOME 2
Assessment criteria Assessment method
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
21/38
7.3 GENERIC OUTCOMES AND CRITICAL CROSS-FIELD OUTCOMES
8. GLOSSARY OF TERMS
The following technical terms are used in this course, and you should be
familiar with these terms and their meanings.
Flocculants, coagulation, settling velocity, rate of settling, sedimentation,
thickener
Sources used for the compilation of the glossary:
9. ASSESSMENT RECORDS
The following guideline for the preparation of report writing are attached to
serve as examples of the implementation of the assessment criteria and
assessment method, as listed in the table 3.1, and you should be familiar
with these examples to prepare and orientate yourself of how the various
assessment criteria are used and applied in the various assessment
methods.
PAGE 21OF 42
Compliance with Critical
cross-field Outcomes
Compliance with Generic
Engineering and Built
Environment Outcomes
Mathematics and Statistics
Communication and written skills
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
22/38
10 EXAMPLE OF A PRACTICAL REPORT
Guidelines for the Preparation of Written Reports
A technical report is a medium commonly used by scientists and engineers
to communicate the results of their work. Frequently the report is the only
tangible product and thus the only evidence for evaluation of the work.
Consequently, it deserves careful attention to quality, packaging, and
distribution.
It is important that the writer(s) of an engineering report keep inmind the needs and interests of the anticipated readers of the
report. The laboratory report should be written with the same
professionalism that would be used to present the results of a major
industrial project. The people who will read it, and need to draw
conclusions from it, can be expected to have technical training, but
probably would not be familiar with the details of the work.
A good report of technical work quantitatively states significant results of
experiments and computations and explains how they were obtained, what
they mean, and how they are useful. The report should be clear, concise,
and accurate. Often the structure of the report must conform to specific
conventions. A format for laboratory reports that is to be used in this
course is given below.
1. Title Page
The title of the report is followed by names of the authors and laboratory
group, the date of submission, and identification of the institution or
organization supporting the work (Tshwane University of Technology,
Department of Chemical & Metallurgical Engineering, CMP33BT).
2. Abstract
PAGE 22OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
23/38
The abstract is a tightly written summary, typically 100 to 300 words long.
This section is important because it is the first impression your report will
make to a reader, and it could very well be the only part of it he or she will
read! (Because of its importance, it is a significant part of the overall
grade.) The abstract should be written as stand alone section of just text.
Its independence means that the use of symbols, tables, and graphs as wellas literature references should be avoided. A good abstract states the
principal objective of the investigation, describes the methodology used
and summarizes the results and conclusions in statements as quantitative
and as general as possible.
The abstract should provide ranges of the experimental parameters (e.g.
the Reynolds number was varied from 100 to 10000), report the most
important results and state how these values compare to expected (i.e.,
literature) ones. (e.g., values for the friction factor in the laminar flow
regime were consistently 15% higher that the predictions of Poiseuille
flow). If the value of a single variable or a short list of numbers is given,
the numbers should give the uncertainty (e.g., solubility at 25C was 25
3 moles/liter) and of course units should be included.
We recommend that you write the abstract last, when your thoughts are
most clearly in focus (i.e., you know all the answers and thus know what to
say!).
3. Table of Contents
A Table of Contents should be included in the report, including a listing of
the Abstract. Appendices should also be listed. All pages should be
numbered, including tables, figures, and appendices.
4. Introduction
The purpose of the Introduction is to place the work in the perspective of
prior work including key literature references, demonstrate its importance,
and state the specific objectives. The Introduction should not exceed two
pages.
PAGE 23OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
24/38
5. Theory
This section is a short, concise statement of the essential empirical and
theoretical relations to be used in interpreting the data or to be tested by
the data. Equations are usually stated with a reference, along with the
pertinent assumptions and limitations. Brief manipulations may beappropriate, but long derivations are relegated to an appendix. The
physical significance of equation parameters should be pointed out.
6. Experimental
A. Apparatus
The objective of this section of the report is to describe the
experimental set-up in enough quantitative detail to enable thereader to completely understand the experiment. Ranges of
independent variables are cited. The model and supplier of any
unique equipment should be cited. Also, a schematic diagram of the
experimental apparatus should be included.
B. Procedure
The objective of this section of the report is to describe the materials
and methods used to obtain the experimental data. Emphasis isplaced on general procedures that are not routine
7. Results
The data, or a representative fraction of them, must be included in this
section. They should be presented graphically. If there are only a few (i.e.
2-3) numbers, these could put into a table if they can be understood. Data
are often not presented in raw form, but are reduced and shown in the way
most clearly supporting the conclusions. Representation of scatter in datais essential. For example, the experimentally determined heat transfer
coefficient is meaningless unless it is accompanied by units and an
estimated uncertainty. Comparison of data with theoretical predictions
and/or previously published values should be included whenever possible.
This may require searching for information in reference books or research
PAGE 24OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
25/38
articles. Comment briefly on unique aspects of the results, in particular its
accuracy. Also comment on the range of the variables covered.
Each graph or diagram is assigned a number (e.g., Figure 1) and should
have a caption that is descriptive of the information contained in the figure.
A restatement of the information on the axes is not an acceptable title.
8. Discussion
All important interpretations which follow from the results and the
underlying theory are logically and quantitatively compared in the
Discussion section. The positive conclusions, comparison with literature
data, and the significance applicability, and reproducibility of the results
are stressed. Quantitative statements about the accuracy and precision of
the results are required. However, when a detailed error analysis isessential to the work, it should be relegated to an Appendix.
9. Conclusions and Recommendations
This section is a summary of the most significant conclusions developed in
the preceding section. Quantitative statements are best. Useful
recommendations to improve the experiment and to extend the work to
other systems, should be included here.
10. Literature Cited
Only references cited in the report are to be listed is this section since it is
not a bibliography covering all references but only the most pertinent ones.
Footnotes on individual pages of the report are not to be used. References
cited in the text of the final project report should give the last name of the
author (both authors when only two; first author et. al. when more than
two) and the corresponding page numbers. An example is given below.
The Reynolds number can be interpreted as the ratio of inertial to viscous
forces at work in the fluid (Denn 37-39).
References are to be listed in alphabetical order according to author or
equivalent and should not be numbered. Use Chemical Abstracts Service
PAGE 25OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
26/38
Source Index journal abbreviations. For the previous example the citation
would be the following:
Richard, J.F. and Zaki, W.N. 1954. Sedimentation and fluidization, Part 1,Transactions of the Institution of Chemical Engineers
. Coulson, J.M., Backhorst, J.R., Harker, J.H., and Richardson J.F. vol 2
4th ed,. Particle technology and separation process. 1991
11. Nomenclature
Symbols used in the report are defined immediately after they are
presented the first time. This section of the report lists all of the symbols
used. Units should be included.
12. Appendices
The appendices contain material of secondary importance: sample
calculations (a sample of all calculations done for the experiment must be
included in the report), error analysis, derivation of theoretical relations,and perhaps graphs, calibration curves and/or schematics. Note that the
appendices should be named in the order of which they appear in the final
project report. In other words Appendix A should be the first appendix
referred to in the text of the report.
11. APPENDICES
11.1 FLOCCULATION AND COAGULATION
JAR TEST PRACTICAL
BACKGROUND
PAGE 26OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
27/38
Coagulation and flocculation processes are an important part of water andwastewater treatment. Coagulation or destabilization of a colloidalsuspension results in joining of minute particles by physical and chemicalprocesses. Flocculation results in formation of a larger settleable structureby bridging. These processes commonly used to remove suspended matteror colour. Adsorption of ionic forms also occurs to varying degrees
depending on the constituents in the water or wastewater.
The jar test is a laboratory technique for determining the most effectivecoagulant, chemical dose, and operating pH for coagulation andflocculation, aluminium or iron salts may be used to coagulate particles andto form settleable flocs composed of the hydrous metal oxide precipitatesand impurities.
Coagulation and flocculation experiments may also be used, in conjunctionwith other tests, to study basic processes including, for example, thekinetics of reaction, and the removal of trace constituents from aqueoussolution.
OBJECTIVES
1. To conduct jar test on a natural surface water in order to estimate anoptimum dosage of aluminium sulphate or ferric sulphate for theremoval of suspended matter or colour.
2. To observe the rate of floc formation and sedimentation.
PROCEDURE
A. DETERMINE OF OPTIMUM COAGULANT DOSAGE
Collect 20 to 50 litres of natural surface water. Analyze the water for pH,turbidity, colour after filtration, and alkalinity. Alternatively, make up asynthetic water sample for testing. Record both the water temperature andambient air temperature.Calculate the amount of alkalinity required to react with the maximumdosage of aluminium or ferric sulphate. If necessary, augment the naturalalkalinity by the addition of 0.1 N Na2CO3 so that the alkalinity will be atleast 0.5 meq/l (25 mg/l as CaCO3).Measure exact 1 litre of water into each jar test reactor. Prepare portions of
the aluminium or ferric sulphate solution which will yield 10 to 50 mg/l asAl2O3 or Fe2O3 when added to the sample aliquots.Mix at 50 rpm to ensure water is completely mixed.Measure chemical volumes to achieve desired dose in each reactor.Increase mixing speed to 250 rpm. Add the chemicals to each reactor nearthe vortex. All reactors should be dosed at the same time.Rapidly mix for 1 min.Reduce mixing to 60 rpm for 9 min.; Observe the reactors at 3 min.
PAGE 27OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
28/38
intervals to detect the formation of flocs. Reduce mixing to 25 rpm for 4min.; Reduce mixing to 10 rpm for 2 min.Turn off mixers and allow particles to settle for 20 min.Measure the turbidity or colour, alkalinity, and pH of the liquid in each jarby sampling at the top, taking care not to disturb the sediment in sampling.Measure the depth of sludge in the beaker.
B DETERMINATION OF OPTIMUM pH
Repeat the jar test of Part A using the observed optimum dosage of ferricsulphate but adjusting sample pH to 6, 7, 8, and 9 with NaOH or H2SO4 priorto adding coagulant.Measure final pH, turbidity or colour of the supernatant of each sample.Measure the depth of sludge in the beaker.Plot turbidity or colour versus pH.
EFFECT OF MIXING (AGGREGATION KINETICS)
Prepare identical (optimum) coagulant dosages for all six beakers.Use the same rapid mix as before but vary the time of slow mix at 30 rpm.Use 5, 10, 15, 20, 30, and 45 minutes for the six jars respectively.Terminate mixing by carefully lifting the paddle from the beaker atappropriate time.Allow 30 minutes for settling.Measure the colour or turbidity and pH of the supernatant in each beaker.
APPARATUS
Jar test apparatus and beakersMagnetic stirrer plus magnetic stirring barsSpectrophotometer or colour comparatorTurbidimeterpH meterAssorted measurement pipettes (1, 5, 10 ml) and volumetric pipettes to 50mlBuretteGlass or plastic funnelsRingstands and rings
MATERIALS
Aluminium sulphate solution, 1 g/l or ferric sulphate solution,1 g/l H2SO4, 2 litres each, 5 x 10-2 M,10-2 M NaOH,, 1 litre, 10-1 MSodium carbonate, 1 litre each, 5 x 10-2 M, 10-2 MIndicators: methyl orange, phenolphthalein
PAGE 28OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
29/38
Synthetic water sample: Add suspended matter with a kaolin,montmorillonite, illite, or bentonite clay and/or the colour with extract fromboiled leaves or with instant coffee to raw water. Turbidity might beincreased to about 40 turbidity units and colour to about 80 colour units(Clay suspension sample should be mixed for 3 days).Buffer solution
Whatman #1 filter paper
REPORT
Prepare tables which facilitate comparisons of coagulant dosages withalkalinity, pH, colour, turbidity, and other changes observed. Plot theinverse of turbidity and colour versus coagulant dosage as part of theanalysis. Plot turbidity versus coagulant dose at different settling times to
determine the influence of floc formation and settling characteristics on theselection of coagulant dosage.Comment on the differences between coagulation with iron and aluminiumsalts. Define the pH ranges over which each salt should result in effectivecoagulation.Determine the rate of aggregation for a particular coagulant dose and pHby plotting the reciprocal of the turbidity versus time. (This would representa second order reaction with respect to turbidity). Also plot the natural logof the reciprocal turbidity (representing a first order reaction) versus time.Determine which gives the best straight line fit of the data and determinethe slope.
References
Richard, J.F. and Zaki, W.N. 1954. Sedimentation and fluidization, Part 1,
Transactions of the Institution of Chemical Engineers.
Coulson, J.M., Backhorst, J.R., Harker, J.H., and Richardson J.F. vol 2 4th ed,.
Particle technology and separation process. 1991.
Geankoplis, C.J Transport Processes and Unit Operations, 3rd., Prantice-Hall,
1993
11.2 SEDIMENTATION EXPERIMENT
1. INTRODUCTION
PAGE 29OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
30/38
Sedimentation is the partial separation or concentration of suspended solid
particles from a liquid by gravity settling. It is a strong function of liquid
viscosity and density, particle size, and concentration of the solution. With
that in mind, experiments can be performed that will allow the engineer to
determine settling times and velocities for liquid-solid suspensions and
slurries. This would enable thickeners to be designed for specific industrialtask.
The sedimentation process is particularly important in the preparation of
industrial or domestic water and purification of wastewater. Many process
applications are also found in metallurgical industry. The beer brewing
industry also has many applications dealing with batch settling and use of
flocculants. Certain clarifiers are added to the beer in order to flocculate
sediment particles so they may later be filtered.
The objective of this experiment is to do settling experiments of the type
that are used to size thickeners for specific industrial applications and to
interpret the results in the context of equipment design.
Objectives:
To study different settling regimes and to determine the relationshipbetween concentration and settling velocity.
To study the concepts of flocculation and anti-flocculation and applythem to thickener operation and design.
To be able to size thickeners based on particle sizes, fluid viscosities,and desired consistencies.
2. Theory
The theoretical ideas used in analysing sedimentation problems
are studied extensively in Chemical Plant course. The methods and
PAGE 30OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
31/38
concepts and concepts covered in this experiment are dealt with in
that class and can be found in the text (2). The main calculations
in the lab are done using the Richardson-Zaki equation and the
Kynch method. The student is urged to have a good grasp of these
concepts when performing this experiment and discuss the aspects
of them thoroughly in the report.
Most correlations used to size thickeners require that the particles behave
according to Stokes law operation is that the Reynolds number must be
less than 0.3. Richardson and Zaki have developed a means to relate the
actual velocity of the particle. With the terminal velocity calculated, Stokes
law can be solved for the diameter of the particle. The Richardson-Zaki
equation is as follows:
=U
UP
T
= Void fraction for the concentration
n = proportional exponent
UP = TRUE PARTICLES HINDERED VELOCITY
(M/S)
UT = terminal velocity, from Stokes law (m/s)
The value of the proportional exponent can be found by:
n = 4.6 + x/D
Where x = particle diameter, in meters
PAGE 31OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
32/38
D = vessel diameter, in meters
Stokes law:
( )v
d g P Ps l=
2
1 8
The Kynch method is a graphical approach that is used to find the settling velocity of a
slurry or suspension over time. However, there are several other constraints that apply
to the Kynch method that should also be kept in mind, such as neglecting wall effects,
assuming uniform particle shape and size, and that the particle velocity reaches zero
at large times .The Kynch method involves constructing tangents to the settling height
and times curves, and the slope of each of these tangents is the velocity at that time.
The most important restriction of the Kynch method is that system must
obey Stokes law. Stokes lawcompares the drag force that resists a settling sphere in
a fluid .the viscosity of that fluid and the shear it creates, and the pressure drag of the
moving sphere, to the terminal velocity of the particle. To prove that a given system of
the particles are within the
Stokes law region, the single particle Reynolds number is calculated. This value must
be below 0.3 for Stokes law to the valid. If this is true, then the settling velocity of the
PAGE 32OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
33/38
particles can be as a function of system characteristics, like particle and fluid densities,
as well as the diameter of the particle.
4. APPARATUS:
To perform this experiment, graduated glass cylinders with a total height of
approximately 1 m are used. The diameter of the cylinder is 0.05 m. The cylinders
should be thoroughly washed and filled with varying concentration of a suspension and
glass beads for the experiment. The suspension to be examined is aC a C O
3 , which is
combined with water to simulate batch settling of fine particles, while glass beads are
mixed with octanol to simulate coarse particles. The settling times are kept by using
the stopwatches provided.
5. METHOD:
The settling experiment is conducted in a cylinder. The suspension C a C O 3 is prepared
at different concentration by weight (to be determined by laboratory supervisor). The
suspension is prepared by mixingC a C O
3 of known quantity with water. The test
column is filled with the suspension up to 0.7 m and agitated with compressed air or
well shaken for about 1 min to provide uniform concentration throughout the depth.
The solids profiles are then determined at different moments of time after agitation.
In addition to profile determination settling of the interface is measured as a function
of time to estimate settling parameters. Graphs at height against time are plotted as
the experiment proceeds. for final compaction reading, a period of 24 hours should
PAGE 33OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
34/38
elapse. Gradients of the initial settling period should be deduced, in order to plot the
initial mass settling rate against concentration.
To determine concentration at any point on the settling curve, a graphical method
employed by Kynch is employed. On the time vs. height graph, a tangent is drawn to
the settling curve, it cuts the vertical axis at a certain point.
The following quantities should be tabulated from reassured data:
Concentration %
Initial solid weight
used (kg)
Volume per unit
weight (m3/kg) *
Height when critical
point reached (m)
Sedimentation Volume
=
H T u b e A r e a
I n i t i a l S o l i d s W e i g h t
C R
Final Sedimentation
height (m)
PAGE 34OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
35/38
Final Volume =
H T u b e A r e a
I n i t i a l S o l i d s W e i g h t
f
Richard, J.F. and Zaki, W.N. 1954. Sedimentation and fluidization, Part
1, Transactions of the Institution of Chemical Engineers.
Coulson, J.M., Backhorst, J.R., Harker, J.H., and Richardson J.F. vol 2 4th ed,.
Particle technology and separation process. 1991.
Geankoplis, C.J Transport Processes and Unit Operations, 3rd., Prantice-Hall,
1993
12. EXAMPLE OF A PRACTICAL REPORT
TSHWANE UNIVERSITY OF TECHNOLOGY
DEPARTMENT OF CHEMICAL AND METTALURGICAL ENGINEERING
REPORT GRADING FORM
Name of Student: ____________________________________________________
PAGE 35OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
36/38
Student Number: _____________________________________________________
Title of Report: ______________________________________________________
Term: _______________________________ DATE: __________________
Subject Max Mark Actual Mark
1. Title Page 1
2. Abstract 6
3. Introduction 2
4. Theoretical Background 3
5. Procedure 2
6. Results 6
7. Discussion of Results 10
8. Conclusion and
Recommendations
4
9. Literature Cited 1
10. Nomenclature 1
11. Organization and Neatness 2
PAGE 36OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
37/38
Appendix
A1 Raw Data 2
A2 Data analysis and Sample
Calculations
10
TOTAL 50
Signed: ____________________________________
Comments:
PAGE 37OF 42
-
7/28/2019 Template Student Laboratory Guide Oct 08 Plant 3A.doc2013 (1)
38/38