lab manual 2013-r1

Faculty of Engineering and Science (FES) Department of Chemical Engineering

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Table of Content

1.0 UNIT OBJECTIVES ............................................................................................................. 4

2.0 UNIT OUTCOMES ............................................................................................................... 4

3.0 SUBJECT SYNOPSIS ........................................................................................................... 4

4.0 LABORATORY SAFETY, RULES AND REGULATIONS ............................................ 5 4.1 General Rules ............................................................................................................... 5 4.2 Laboratory Safety Rules .............................................................................................. 6

5.0 RESPONSIBILITY OF STUDENTS ................................................................................... 7

6.0 ASSESSMENTS ..................................................................................................................... 8 6.1 Breakdown of Marks ................................................................................................... 8 6.2 Overall Performance in Laboratory during Experiment Session (10 marks) .............. 8 6.3 Laboratory Reports (10 marks) .................................................................................... 9

7.0 LABORATORY REPORT WRITING ............................................................................. 10 7.1 Content ....................................................................................................................... 10 7.2 Specification .............................................................................................................. 12 7.3 Formatting .................................................................................................................. 13

Appendix A: Material Safety Data Sheet (MSDS)..123

1.0 UNIT OBJECTIVES

This subject will help the students to develop their skills of collecting, analysing and presenting the results of data acquired within a well-defined experimental system. The specific objectives are to: combine elements of theory and practice particularly in chemical reaction, process control

fluid mechanics, bioprocess and catalysis, familiarise with laboratory safety procedures, develop and demonstrate a knowledge of experimental error analysis, probability and

statistics, work collaboratively within a group setting, develop skills in handling, manipulating and maintaining basic engineering machinery, develop practical skills to plan and design laboratory experiments.

2.0 UNIT OUTCOMES

On completion of this unit, a student should be able to: collect and analyse experimental data and its relationship to theoretical principles of

chemical reaction control process fluid mechanics catalysis and bioprocess

operate laboratory experiments safely, prepare a written laboratory report that clearly present the experimental results, analysis, and

relationship to theory, develop skills in operating common chemical engineering equipment and measurement

apparatus.

3.0 SUBJECT SYNOPSIS

A laboratory course in pilot-scale processes involving chemical reaction, process control, fluid mechanics, bioprocess and catalysis. Students will acquire the skills in project definition, experimental operation, analytical procedures, data analysis and technical reports preparation.

4.0 LABORATORY SAFETY, RULES AND REGULATIONS

Laboratory safety is the top priority and this requires all people in the laboratory to be observing safe practices at all times!

4.1 General Rules

Students must abide the dress code while working in the laboratory.

Laboratory coat must be worn all the time when working in the laboratory.

Only closed toe shoes are allowed in the laboratory. Do not wear sandals, slippers and high heel shoes inside the laboratory.

Students with long hair must get their hair tied up tidily when doing laboratory work.

Bags and other belongings must be kept at the designated places.

Foods, drinks and smoking are strictly prohibited inside the laboratory.

Noise must be kept to the minimum as a courtesy to respect others.

Students are not allowed to work alone without the supervision of laboratory instructor/officer. There must be at least 2 persons present in the laboratory at the same time.

Students are not allowed to bring any outsiders (non-registered parties) into the laboratory.

Any unauthorized experiment without the knowledge of laboratory instructor is prohibited.

All instrument and equipment must be handled with care.

Workspace has to be cleaned and tidied up after the experiment completed. Instrument and equipment must be returned after used.

Students are strictly prohibited to take any equipment or any technical manuals out from the laboratory without the permission of laboratory instructor/officer.

Students are required to instil an instinctive awareness towards property value of laboratory equipment and to be responsible when using it. Any damages can cause to jeopardise the success of not only the individual work but also to the university.

Do not attempt to remove and dismantle any parts of the equipment from its original design without permission.

Students shall be liable for damages of equipment caused by individual negligence. If damages occurred, an investigation will take place to identify the causes and the names of the involved students will be recorded for faculty attention.

Please check the notice board regularly and pay attention to laboratory announcements.

Disciplinary action shall be taken against those students who are failed to abide the rules and regulations.

4.2 Laboratory Safety Rules

It is always a good practice and the responsibility of an individual to keep a tidy working condition in laboratory.

It is important for each student to follow the procedures given by the laboratory instructor when conducting laboratory experiment.

Before any experiment starts, students must study the information / precaution steps and understand the procedures mentioned in the given laboratory sheet.

Students should report immediately to laboratory instructor/officer if the laboratory equipment is suspected to be malfunctioning or faulty.

Student should report immediately to the laboratory instructor/officer if discovered any damages on equipment or any hazardous situation.

Students should report immediately to the laboratory instructor/officer if any injury occurred. If there is a tingling feel when working with electrical devices, stop and switch off the devices

immediately. Place a warning note before reporting to the laboratory instructor/officer and wait for further instruction.

Do not work with electricity under wet condition in laboratory. Electric shock is a serious fatal error due to human negligence and may cause death.

Students are required to wear goggles, gloves, apron and mask when handling corrosive or active chemicals.

Hazardous chemicals must be properly stored and labelled in a designated place. Students must acquire and study the material safety data sheet of a particular chemical before using it.

(Extracted from Student Laboratory Guidelines. Refer to UTAR Occupational Safety and Health website www.utar.edu.my/osh for complete rules & regulations at the following link: http://www.utar.edu.my/osh/file/Student%20Laboratory%20Guidelines1(07.09.08).doc)

5.0 RESPONSIBILITY OF STUDENTS

Attendance is compulsory. Attendance shall be taken during the laboratory session.

Please sign your attendance when you attend the laboratory session.

Laboratory report can only be accepted for submission if the student has attended the laboratory session.

Student must be punctual to attend laboratory session.

Students who are late for more than 30 minutes will be barred from attending the laboratory session. Only students with valid reason of medical basis or unforeseen circumstances can be considered to apply for laboratory replacement.

Students are expected to study the lab sheet before the laboratory session start.

Student must understand all the safety measures / precaution steps before starting any experiments.

Student must complete the experiment within the allocated duration of laboratory session.

Students are responsible for the condition of their working area at the end of each laboratory session. All power to the equipment and instruments should be turned off, and cooling water flows should be shut off. Glassware used should be cleaned and dried.

Students have to pass up their experiment result to laboratory officer on the same day after every experiment. A copy of the experimental result (with chop) must be attached together with the laboratory report.

Fabricating results and plagiarism are strictly prohibited. Strict action will be taken if student is found fabricating results or copy from others.

Students have to pass up their laboratory report (group report) 1 week after the date of experiment to laboratory officer.

6.0 ASSESSMENTS

6.1 Breakdown of Marks

Description Marks

Overall Performance during Experiment Session and Laboratory Reports 70%

Laboratory Test 30%

6.2 Overall Performance in Laboratory during Experiment Session (10 marks) This is a group assessment. Each student performance in the laboratory during the experiment session will be observed and marks will be given to the group as a whole.

The performance will be assessed based on the following criteria:

Criteria Description Marks

Safety Awareness

Adhere to laboratory safety, rules and regulation. Abide to dress code (lab coat, shoes, long pants etc.)

while working in the laboratory. Understand all the safety measures / precaution steps

before starting any experiments. Proper safety equipment such as goggles, gloves etc.

were used when necessary. Show precautions when handling chemicals.

10

Punctuality Attend laboratory session on time.

Preparation Show understanding in the experiment that are about to carry out.

Cleanliness and Responsibility

Workspace is clean and tidied up after the experiment completed.

Instrument and equipment are returned orderly after use.

Show instinctive awareness towards property value of laboratory equipment and instruments and their responsibility in handling them.

6.3 Laboratory Reports (10 marks) Laboratory report will be assessed based on the following criteria:

Criteria Description Marks

Overall Presentation of Report

Organisation of report with the correct format and necessary information such as titles, figure explanations.

Report is written in clear and concise English.

2.5

Observations / Data / Result Presentation

Valid observations, consistent with event and demonstrate attention to detail.

Data are presented in an organised manner. Quality of data reflects students ability to perform

experiment successfully and utilise computer software in analysis (if applicable).

All calculations and graphs are correct.

2.5

Discussion Discussion shows complete understanding of experiment and the significance of data.

Logical explanation for problems in the data.

3.5

Conclusion Summary of key findings in a clear statement. Clearly show relationships between data and

conclusion. Express views on the weakness of the experimental

design (if there is any), or what is the implication of the conclusion.

1.5

TOTAL 10

7.0 LABORATORY REPORT WRITING

Laboratory reports are the most frequent document written by an engineering student. A laboratory report should not be used to merely record the expected and observed results but demonstrate the writers comprehension of the concept behind the data. A good laboratory report should address the following questions:

Why? Why did I do this particular experiment?

How? How did I actually carry it out?

What? What did I find? What were my results?

So What? What does my result mean? What is the significance of the result? What are my conclusions?

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The laboratory report should be written with the same professionalism that would be used to present the results of a major industrial project. 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.

7.1 Content

The laboratory report should follow the following format and all the pages should be numbered except the cover page.

Section Max number of lines / pages

UTAR Laboratory Cover Page

1) Title of Experiment 1 2 lines

2) Objectives of Experiment 1 5 lines 3) Introduction

Provide a scientific background related to the experiment and provides the reader with justification for why the work was carried out.

page

Section Max number of lines / pages

4) Materials and Equipment List only the materials/chemicals and equipment/apparatus used in the experiment.

page

5) Results and Calculations Present the data obtained from the experiment. The data have to be presented in a clear and understandable manner. All tables must be clearly labelled with numbers and titles. All necessary calculations based on the raw data should be provided in this section.

depends on results and calculations

6) Discussion This is the most important section where detailed analysis of the experimental data should be provided. Factors/issues related to the obtained results must be explained. Graphic materials based on the experimental data should be presented and discussed in this section. All graphs must be clearly labelled with numbers and titles. Strategies that can use in the discussion: compare expected results with those obtained explain the results in terms of theoretical issues what do the results indicate? what is the significance of the results? relate results to the experimental objectives analyse experimental error what ambiguities exist? find logical explanation for problems in the data what questions might we raise?

3 pages

7) Conclusion Based on the discussion provided, summarise the key findings in a clear statement. Additionally, the conclusion can also be used to express views on the weakness of the experimental design (if there is any), or what is the implication of your conclusion.

5 lines

8) References List all references used in the preparation of the report. Information obtained from any source, including the Internet, is covered by copyright law. Any source referred in the report must be acknowledged, both within the text and at the end of it. The format should follow the American Psychological Association (APA) referencing style.

depends on references

There shall be no appendix for the report. All information should be summarised into the discussion section.

The laboratory reports should be arranged so as to include the major sections described above, but students are free to insert additional subsections if they help to organise and clarify material and information for the reader.

While the results and information contained in the report are of primary importance, students should not underestimate the importance of a neat, easy-to-follow, well-organised presentation. Pay attention to the appearance of the graphs, figures and tables, and to the ease with which the reader can interpret them. Good results can be easily obscured by careless organisation and presentation.

Students should take note on verb tense. These two points should help in writing the report: By the time you get to the stage of writing a laboratory report, the experiment is already

finished. Use past tense when talking about the experiment. Example: The objectives of the experiment were

The report, the theory and permanent equipment still exist; therefore, use present tense: The objective of this report is.. Newtons Law of motion is. The transmission electron microscope produces micrographs

7.2 Specification

Specification Description

Language The report should be written in British (UK) English.

Paper White simile A4 size paper (210 297 mm)

Printing Report must be computer typewritten using word processor and printed preferably double sided.

Printing must be of high quality. Text and figures must be clear and legible.

Binding Staple on top left corner

7.3 Formatting

Formatting Description

Page Margin Left margin : 4.0 cm Right, Top, Bottom margins : 2.5 cm Header and Footer margins : 1.5 cm

Typesetting and Spacing

Font Type : Times New Roman Font Size : 12 pt Section Title : Uppercase, Bold, Align left Subsection Title : Title Case, Bold, Align left Symbol for variable : Italic (e.g. m, P, T, v, , , ) General Spacing : 1.5 lines General alignment for texts in paragraph should be justified.

The format for writing units, symbols, numbers etc. in the report follows the International System of Units (SI). The following sections give some common descriptions of the writing styles. For complete and thorough information, refer to the SI Brochure available online at http://www.bipm.org/en/si/si_brochure/. The use of the correct symbols and names for SI units, and for units in general are mandatory in the report. In this way ambiguities and misunderstandings in the values of quantities can be avoided.

Style Description

Numbers Avoid starting a sentence with a number or symbol.

Number has to be used together with unit; if not it has to be spelled out (e.g. three cats; not 3 cats).

If the number is between +1 and -1, the decimal marker is always preceded by a zero (e.g. 0.15; not .15).

Numbers with many digits may be divided into groups of three by a thin space, in order to facilitate reading. Neither dots nor commas are inserted in the spaces between the groups (e.g. 43 765 589, 58.159 25; not 43,765,589; not 58.159,25).

When there are only four digits before or after the decimal marker, it is customary not to use a space to isolate a single digit (e.g. 5879, 1.5681)

When multiplying numbers, use only the multiplication sign with a space before and after, not centre dot () nor the letter x or X (e.g. 25 5.3; not 25 5.3; not 25 x 5.3).

Style Description

Units If possible, use SI units; although other commonly used non-SI units are also acceptable (e.g. C for temperature, bar for pressure).

Spacing One spacing between number and unit (e.g. 5 cm, 50 C, 30 %; not

5cm; not 50C; not 30%). Exception for angular degree (), minute () and second () (e.g. 3, 45)

which are placed immediately after the number.

Symbols for Units Use symbol for units and not their abbreviation (e.g. 5 s; not 5 sec.). Symbols for units are written in upright type i.e. not italic (e.g. m for

metres, g for grams). This is to differentiate them from italic type symbols used for variables (e.g. m for mass).

Symbols for units are written in lowercase, except for symbols derived from the name of a person, which start with uppercase. However, the unit name itself is written in lowercase. (e.g. the unit for pressure is named after Blaise Pascal; the unit itself is written as pascal whereas the symbol is Pa; 5 Pa or 5 pascal; 5 J or 5 joule; 5 N or 5 newton)

Symbols are not pluralised (e.g. 5 kg; not 5 kgs). Symbols do not have an appended period / full stop (.) unless at the end

of a sentence.

Symbols derived from multiple units by multiplication are joined with a space or centre dot () (e.g. N m for Nm). Hyphens (-) should not be used (e.g. not N-m) [Note: centre dot () is different from period / full stop (.); centre dot is available under command Insert > Symbol].

Symbols formed by division of two units are joined with a solidus ( ) (slash ( / ) is also acceptable) or given as a negative exponent (e.g. m/s or m s-1).

Only one solidus should be used (e.g. kgm-1s-2 or kg/(ms2); not kg/m/s2).

Do not mix unit symbols and unit names within one expression (e.g. coulomb per kilogram; not coulomb per kg).

Style Description

SI Prefixes

Factor Name Symbol Factor Name Symbol 101 deca da 101 deci d 102 hecto h 102 centi c 103 kilo k 103 milli m 106 mega M 106 micro 109 giga G 109 nano n 1012 tera T 1012 pico p 1015 peta P 1015 femto f 1018 exa E 1018 atto a 1021 zetta Z 1021 zepto z 1024 yotta Y 1024 yocto y

Prefix symbols are attached to unit symbols without a space or hyphen (-) between the prefix symbol and the unit symbol (e.g. km; not k m; not k-m).

The same also apply for prefix names (e.g. kilometre; not kilo metre; not kilo-metre)

Prefix symbols are written in upright type, i.e. not italic. (e.g. kPa; not kPa).

All prefix symbols larger than kilo (103) are uppercase; the rest are lowercase (see table above) (e.g. MW, GHz, kW, mg, nm).

All prefix names are lowercase, except at the beginning of a sentence (e.g. megawatt, gigahertz, kilowatt, milligram, nanometre)

A prefix is never used in isolation; and compound prefixes are never used (e.g. 10-9 m is nm or nanometre; not mm or millimicrometre).

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Experiment 1 Batch Reactor

1.0 OBJECTIVES OF EXPERIMENT

To determine the reaction rate of saponification reaction at given temperature by measuring the conversion against reaction time.

To evaluate the reaction rate constant at constant temperature using differential and integral methods of analysis.

To evaluate the rate constant at different temperatures and activation energy determination from Arrehenius Plot.

2.0 INTRODUCTION

In batch reactions, there are no feed or exit streams and therefore the mass balance equation for species A in an element of reactor volume V obeys the following statement:

Rate of A produced within volume element = Rate of A accumulated within volume element

In a batch reactor, the process in the reactor is at unsteady state by its nature. In this process, one or more variables vary with time. The longer the reactant is in the reactor, the more reactant is converted to product until either equilibrium is reached or the reactant is exhausted.

2.1 Theory

In a constant volume reactor, volume element means the volume of reaction mixture, and not the volume of reactor. Thus, this term means a constant-density reaction system. Most liquid phase reactions as well as gas phase reactions occurring in a constant volume reactor falls in this class.

In Constant Volume System:

dtdC

VdtdN

r iii ==/

(1)

Thus, the rate of reaction of any component is given by the rate of change of its concentration or partial pressure no matter how we choose to follow the progress of the reaction.

Suppose that NAo is the initial amount of A in the reactor at time t = 0, and that NA is the amount present at time t. The conversion of A in the constant volume system is then given by

( ) ( )Ao

AAo

Ao

AAoA C

CCN

NNX

=

= (2)

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The rate of reaction (disappearance of component A), is, in general given by

VdtdN

r AA/

= (3)

dtdXNVr AAoA = (4)

Integrating the above equation gives,

( ) = VrdXNt

A

AAo (5)

where t is the time required to achieve a conversion XA for either isothermal or non-isothermal operation.

dtdXCr AAoA = (6)

The time t necessary to achieve a conversion XA is:

=

A

AAo

r

dXCt (7)

In terms of concentrations, if the density of the fluid remains constant.

=

A

A

r

dCt (8)

Figure 2.1 shows the graphical representation of batch reactor Equation (8),

Figure 2.1: Reaction Rate Constant is almost always strongly dependent on Temperature

)(1

Ar

CA CA0 CA

Area = t

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The Arrhenius Law is given by

k (T) = AeE / RT (9)

where A = pre-exponential factor of frequency factor E = activation energy, kJ/mol or cal/mol

3.0 EQUIPMENT BATCH REACTOR

Figure 3.1: Batch Reactor

4.0 OPERATING PROCEDURES

4.1 Pre-experiment Procedures

1. Read and understand the theory of batch reactor. 2. Read and understand the equipment used in the experiment (batch reactor). 3. Read the safety precautions and chemical hazards before conducting the experiment. 4. Read the Material Safety Data Sheet (MSDS) for the chemicals used in the experiment in

Appendix A. 5. Prepare the following apparatus and materials needed for the experiment:

Beaker: 2 L 1, 1 L 1, 250 mL 2 Measuring Cylinder: 100 mL 2 Glass rod Conductivity Meter Electric Stirrer

Overhead Stirrer

Water Bath

Beaker (2L)

Conductivity Meter

Beaker (1L)

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Water bath Stopwatch 5 L of 0.1 M sodium hydroxide, NaOH 2 L of 0.1 M ethyl acetate, Et(Ac) 500 mL of 0.1 M sodium acetate, Na(Ac) 1 L of deionised water, H2O

5.0 CHEMICAL HAZARDS, SAFETY AND PRECAUTIONS

5.1 Chemical Hazards (refer MSDS in Appendix A for more details) Sodium hydroxide (NaOH) solid and its solutions are corrosive. Spilled chemicals may damage

the apparatus. Contact with skin can cause burn and contact with the eyes can cause serious long-term damage. Significant heat is released when NaOH dissolves in water.

Ethyl acetate (Et(Ac)) is very flammable, so constitutes a fire risk. It can be ignited by flames, but also by contact with items such as hot plates or hot air guns.

Ethanol (EtOH) is very flammable, so constitutes a fire risk. Ethanol contact with the eyes can cause considerable irritation.

Sodium acetate (Na(Ac)) may be harmful if a large amount is swallowed.

5.2 Safety Precautions

Always wear safety glasses, mask and gloves when handling chemicals. Do not allow the solution to come into contact with your skin or eyes.

Should any chemicals come into contact with the body, rinse off immediately with plenty of water and inform the laboratory instructor/officer. Seek medical treatment if symptoms persist.

Wash away any splashes of chemical immediately. Do not touch the reactor when in operation and beware of scalding. Ensure proper ventilation in laboratory. No open flames or hot items in the vicinity. Dispose of all unused chemicals in an appropriate manner after the experiment. Under no

circumstances should the chemicals be allowed to flow into sinks or drains. Wash your hands thoroughly with soap after the experiment.

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6.0 EXPERIMENTS

6.1 Experiment 1: Calibration Curve Conductivity versus Conversion

The reaction to be studied is the saponification reaction of ethyl acetate Et(Ac) and sodium hydroxide NaOH. Since this is a second order reaction, the rate of reaction depends on both the concentrations of Et(Ac) and NaOH. However, for analysis purposes, the reaction will be carried out using equimolar feeds of Et(Ac) and NaOH solutions with the same initial concentrations. This ensures that both concentrations are similar throughout the reaction.

NaOH + Et(Ac) Na(Ac) + EtOH

Create a calibration curve: conductivity vs conversion for the reaction between 0.1M Et(Ac) and 0.1M NaOH.

6.2 Experiment 2: Determine the Rate of Reactions

Setup the apparatus as per Figure 3.1. Conduct the experiment with at least Four different temperatures.

7.0 RESULTS ANALYSIS AND DISCUSSION

Discuss all your results. The questions below only serve as a guideline. Your discussion should not only limit to these questions.

1. Evaluate the rate constants for forward and reverse reaction treating the saponification reaction as reversible reaction.

2. What is the time required for 95% conversion?

3. What are the advantages and disadvantages of obtaining kinetic data in a batch reactor?

4. What is the most appropriate method of continuously monitoring the concentration of reactants during saponification reaction?

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Experiment 2 Continuous Stirred Tank Reactor (CSTR)


To observe and control the operation of a continuous-stirred tank reactor. To determine the effects of flow rate on conversion rate in a continuous-stirred tank reactor.

2.0 INTRODUCTION

The main feature of CSTR is that mixing is complete so that properties such as temperature and concentration of the reaction mixture are uniform in all parts of the reactor. By studying the rate data for saponification reaction of ethyl acetate and sodium hydroxide to form sodium acetate in a continuous stirred tank reactor (CSTR), one can design a CSTR from the rate data.

In kinetic studies each steady-state run gives, without integration, the reaction rate for the conditions within the reactor. The ease of interpretation of data from a CSTR makes its use very attractive in kinetic studies.

The reaction rate constant can be evaluated from the reaction rate data at a given temperature. The rate data analysis depends on the type of reaction and rate constant can be evaluated by integral method of analysis. The rate constant is determined at different temperatures. The effect of mixing over kinetic data in CSTR is also determined. The reaction activation energy can be determined from Arrhenius plot of reaction rate constant against reaction temperature.

2.1 Theory

The reaction rate constant is independent of the concentrations of the species involved in the reaction and strongly dependent on the temperature. The reaction rate constant dependence on temperature is given as

=

RTEATk exp)( (1)

where A = pre-exponential factor of frequency factor E = activation energy, kJ/mol or cal/mol

The conservation principle requires that the mass of species A in an element of reactor volume V obey the following statement:

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=

+

element umewithin voldaccumulateA of Rate

element umewithin volproducedA of Rate

element volumeofout A of Rate

element volume intoA of Rate

Applying the above equation to CSTR with no accumulation of material A in the reactor, the CSTR volume necessary to achieve a specified conversion XA is

( )AAA

r

XFV

=0

(2)

where FA0 = initial feed rate of A rA = rate of reaction

Since the exit composition from the reactor is identical to the composition inside the reactor, the rate of reaction is evaluated at the exit conditions.

For a typical reaction

Products BA + k (3)

the rate of reaction (rA) treating the reaction as first order with respect to A and B is

( )( )AAABAA

XXkCCkCr

=

=

102 (4)

Assuming CB0 = CA0, M0 = CB0/CA0 = 1, CB0 CA0= CA02.

Once the rate of reaction (rA) is obtained from Eq. (2), the value of k can be obtained from Eq. (4).

Consider a chemical reaction between ethyl acetate and sodium hydroxide. This process is also known as saponification. The reaction is reversible, and is described by

CH3COOCH2CH3 + NaOH HOCH2CH3 + CH3COONa (ehtyl acetate) (sodium hydroxide) (ethanol) (sodium acetate)

The ethyl acetate molecules split into acetate ions and ethanol molecules, consuming hydroxide ions provided by sodium hydroxide in the process. The progress of the reaction can thus be tracked accurately by the change in hydroxide ions. This can be observed by the conductivity change in the reactor vessel, since the presence of hydroxide ions increase the conductivity in a solution.

As the conversion increases, the hydroxide ions deplete to form ethanol, and this should be observed by a decrease in conductivity. The percentage conversion of the reactants can thus be determined from the conductivity values as follows:

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( )( ) %1001

=

eo

eX

(5)

where = measured value for conductivity (mS/cm) o = initial conductivity for 2.3% sodium hydroxide solution (128.2 mS/cm) e = conductivity of the end product (1 mS/cm for a 5% sodium acetate solution)

It can be observed that for each mole of sodium acetate and ethanol produced, one mole of ethyl acetate and sodium hydroxide is consumed.

3.0 EQUIPMENT CONTINUOUS STIRRED TANK REACTOR (CSTR) This CSTR unit is used to demonstrate the basics of chemical processing in continuous flow reactors. The apparatus comprised of two glass feed tanks, a chemical reactor, a cooling/heating water reservoir, pumps and a process control console.

The reactant tanks are provided with heating coils to bring reactants to reaction temperatures before dosing into the reactor. The dosing peristaltic pumps are fitted with speed controls to adjust the feeding rate while the control console is fitted with a temperature control, conductivity meter and a stirrer control unit.

A - Main Power Switch

B - Conductivity and Temperature Meters

C - Hot Water Pump

D - Sump Tank

E - Hot Water Tank

F - NaOH Feed Tank

G - Et(Ac) Feed Tank H - Reactor Vessel

I - Dosing Pumps

J - Tank Drain Valves

K - Hot Water Valves

L - Pump Bypass Valve

Figure 3.1: Continuous Stirred Tank Reactor

J

K

L

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1. Read and understand the theory of CSTR. 2. Read and understand the equipment used in the experiment (CSTR). 3. Read the safety precautions and chemical hazards before conducting the experiment. 4. Read the Material Safety Data Sheet (MSDS) for the chemicals used in the experiment in


Beaker: 2 L 2

Measuring Cylinder: 100 ml 1 Volumetric Flask: 1 L 1 Glass rod Stopwatch 15 L of 2.3% sodium hydroxide (NaOH) solution 15 L of 5% ethyl acetate (Et(Ac)) solution 500 mL of 0.5 M sodium acetate, Na(Ac) 1 L of deionised water, H2O










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Wash away any splashes of chemical immediately. Do not touch the reactor when in operation and beware of scalding. Ensure proper ventilation in laboratory. No open flames or hot items in the vicinity. Ensure that the drain valves (J) for the sump tank and hot water tank are fully closed. Ensure that the drain valve for the reactor vessel (H) is fully closed. Ensure that all the hot water valves (K) are fully closed. Leave the pump bypass valve (L)

partially open.

Fill the hot water tank with water until 80% full.

Dispose of all unused chemicals in an appropriate manner after the experiment. Under no circumstances should the chemicals be allowed to flow into sinks or drains.

Wash your hands thoroughly with soap after the experiment.

6.0 EXPERIMENTS





6.2 Experiment 2: Determine the Effects of Flow Rate on Conversion Rate

Prepare the equipment until the set temperature. Conduct the experiment with at least Three different dosing rates.

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1. Define residence time. How do you determine the residence time of a CSTR with fixed volume?

2. How does the volume of a CSTR affect the conversion of reactants into products?

3. Does temperature affect the conversion and conversion rate? Discuss the temperature effects on chemical reactions.

4. Le Chateliers principle states that chemical reactions favour the direction which opposes changes to a system in equilibrium. How would you increase the conversion in a system that produces ammonia? (Note - the production of ammonia from nitrogen and hydrogen gas is exothermic.)

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Experiment 3 Plug Flow Reactor (PFR)


To carry out a saponification reaction between NaOH and Et(Ac) in a PFR. To determine the reaction rate constant. To determine the effect of residence time on the conversion in a PFR.

2.0 INTRODUCTION

The plug flow reactor (PFR) (or sometimes called the tubular flow reactor (TFR)) is commonly used in industry in addition to continuous stirred tank reactor (CSTR) and batch reactor. It consists of a cylindrical pipe and is normally operated at steady state. For analysis purposes, the flow in the system is considered to be highly turbulent and may be modelled by that of plug flow. Thus, there is no radial variation in concentration along the pipe.

In a PFR, the reactants are continually consumed as they flow down the length of the reactor. In modelling a tubular reactor, the concentration is assumed to vary continuously in the axial direction through the reactor. Consequently, the reaction rate, which is a function of concentration for all but zero order reactions, will also vary axially.

2.1 Theory

Figure 2.1: Plug Flow Reactor

To develop the PFR design equation, the reactor volume shall be divided into a number of sub-volumes so that within each sub-volume V, the reaction may be considered spatially uniform. Assuming that the sub-volume is located a distance y from the entrance of the reactor, then FA(y) is the molar flow rate of A into volume V and FA (y + y) is the molar flow rate of A out of the volume.

FA0 FA

FA(y) V

FA (y+ y)

y y

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In a spatially uniform sub-volume V,

=V

AA VrdVr (1)

For a plug flow reactor at steady state, the general mole balance is reduced to

0=dt

dN A

0)()( =++ VryyFyF AAA (2)

In the above expression, rA is an indirect function of y. That is, rA is a function of reactant concentration, which is a function of the position, y down the reactor. The volume, V is the product of the cross-sectional area, A of the reactor and the reactor length, y,

yAV = (3)

Substituting Eq. (3) into Eq. (2) and taking the limit as y approaches zero yields

AAAA

yAr

dydF

yyFyyF

==

+

)()(lim0

(4)

It is usually most convenient to have the reactor volume, V rather than the reactor length, y as the independent variable. Accordingly, the variables Ady can be changed to dV to obtain this form of the design equation for a PFR,

AA r

dVdF

= (5)

Note that for a reactor in which the cross-sectional area, A varies along the length of the reactor, the design equation remains unchanged. This means that the extent of reaction in a plug flow reactor does not depend on its shape, but only on its total volume.

If FA0 is the molar flow rate of species A fed to a system operating at steady state, the molar flow rate at which species A reacting within the entire system will be FA0X. The molar feed rate of A to the system minus the rate of reaction of A within the system equals the molar flow rate of A leaving the system, FA. This is shown in mathematical form to be

( )XFXFFF AAAA == 1000 (6)

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The entering molar flow rate FA0 is just the product of the entering concentration CA0 and the entering volumetric flow rate V0 ,

000 VCF AA = (7)

AA rdVdXF =0 (8)

Rearranging and integrating Eq. (8) with the limit V = 0 when X = 0, we obtain the plug flow reactor volume necessary to achieve a specified conversion X,

=

X

AA

r

dXFV0

0 (9)

3.0 EQUIPMENT PLUG FLOW REACTOR This Plug Flow Reactor has been designed for experiments on chemical reactions in liquid phase under isothermal and adiabatic conditions. The unit comes complete with a jacketed plug flow reactor, individual reactant feed tanks and pumps, temperature and conductivity measuring sensors.

V1

V5

FI02

TIC01

V7

V14

PumpP1

Feed TankB1(30-L)

Feed TankB2(30-L)

PumpP2

LS1

LS2

Vent

Tubular ReactorR1(0.4-L)

M1

V13

V19

V20

Drain

Waste TankB3

(60-L)

WaterDe-ionizer

c.w.

PumpP3

V17

V18

V11V10V12

V15

QI02

V9

FI01

Drain

Drain

Drain

Sampling

QI01

V8

V4

V3

V16

Water JacketB4(10-L)

Pre-heaterB5(3-L)

ElectricalCart. HeaterW1, W2(2x1.0 kW)

V2

V6

c.w.V21

Drain

TI02

Figure 3.1: Process Flow Diagram for Plug Flow Reactor Unit

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1. Read and understand the theory of plug flow reactor. 2. Read and understand the equipment used in the experiment (plug flow reactor). 3. Read the safety precautions and chemical hazards before conducting the experiment. 4. Read the Material Safety Data Sheet (MSDS) for the chemicals used in the experiment in


Beaker: 100 mL 2

Measuring Cylinder: 50 mL 2 Conical Flask: 250 mL 2 Burette pH Indicators 30 L of 0.1 M sodium hydroxide, NaOH 30 L of 0.1 M ethyl acetate, Et(Ac) 500 mL of 0.1 M sodium acetate, Na(Ac) 1 L of 0.25 M Hydrochloric Acid, HCl 1 L of deionised water, H2O

4.2 General Shutdown Procedures

1. Switch off all the pumps P1, P2 and P3. Close valves V2 and V6. 2. Switch off the stirrer. 3. Switch off the main power switch at the control panel and power supply. 4. Dispose all chemicals into the container provided.





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Wash away any splashes of chemical immediately. Do not touch the reactor when in operation and beware of scalding. E Ensure that the drain valve (V16) of waste tank B3 is fully closed. Ensure that all valves are initially closed except pump bypass valves V3, V7 and V17. Fill feed tank B1 with the NaOH solution and feed tank B2 with the Et(Ac) solution. Fill up the water jacket B4 and pre-heater B5 with clean water. Ensure proper ventilation in laboratory. No open flames or hot items in the vicinity. Dispose of all unused chemicals in an appropriate manner after the experiment. Under no

circumstances should the chemicals be allowed to flow into sinks or drains. Wash your hands thoroughly with soap after the experiment.

6.0 EXPERIMENTS





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Experiment 2: Investigate the Effect of Residence Time on the Reaction in a PFR

Conduct the experiment with Five different flow rates (ensure both feed flow rates are the same all the time). Record both the inlet and outlet steady state conductivity values then collect a 50 ml sample and immediately run Experiment 3.

Reminder:

Open valves V2 & V6 (feed pumps suction), V4 & V8 (feed pumps discharge), and V9 & V11 (feed to reactor). Switch on both the feed pumps P1 and P2. Adjust valves V4 and V8 to obtain the pre-set flow rate. Then close valves V9 and V11 follow by open valves V13 & V18 (pump P3 suction and discharge), and switch on pump P3 (to circulate the water through pre-heater B5) and stirrer. Lastly, open valves V9 and V11 again where allow both solutions to enter reactor R1 and overflow into the waste tank B3. Record the flow rates of the feeds and start monitoring the inlet (QI-01) and outlet (QI-02) conductivity.

6.2 Experiment 3: Back Titration

This experiment is carried out to verify the conductivity on the conversion of NaOH in the reactor. It is based on the principle of quenching the sample (from Exp 2) with excess acid (10 ml 0.25M HCl) to stop any further reactions and then back titrating with a base (0.1 M NaOH) to determine the amount of unreacted acid.



Determine the different reactor residence times, the value of the reaction rate constant, k and the rate of reaction, rA.

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Experiment 4 Level Process Control


To understand the characteristic of proportional (P), proportional-integral (PI) and proportional-integral-derivative (PID) controller in a level control loop.

To observed the different types of process level responses to P, PI and PID controller. To determine the optimum controller tuning parameter(s) for P, PI and PID controller.

2.0 INTRODUCTION

A fundamental component of any industrial process control system is the feedback control loop. It consists of the process, the measurement, the controller, and the final control element. If all these elements are interconnected, that is, if information can be passed continuously around the loop, this is closed-loop control and automatic feedback generally exists.

Automatic control requires signal system to close the loop and provide the means for information flow. This means that the controller must be able to move the valve, the valve must be able to affect the measurement, and the measurement signal must be reported to the controller. Without this feedback, we do not have automatic control.

2.1 Proportional Control

When a process has small capacity, it usually responds quickly to upsets. Proportional control attempts to stabilise the system and avoid fluctuations by responding to the magnitude as well as the direction of the error.

The relationship between the output and the width of the measurement span is called the proportional band (PB) and is expressed in percentage. For example, a 20% proportional band is narrow; it provides sensitive control because 100% output change is produced by only 20% measurement change. Conversely, a 500% proportional band is very wide with only 20% of the possible output produced by 100% change in measurement.

The proportional controller calculates the amount of error between the measurement and set point, amplifies it, and positions the final control element to reduce the error. The magnitude of the corrective action is proportional to the error. When there is a process upset, the valve must change position to keep the controlled variable at the set point. The output from the controller (which controls the valve position) must assume a new value, different from the original (the set point), before equilibrium can again be reached. This new value of the controlled variable is offset from the set point.

Curve C in Figure 2.1 shows system response when the proportional band in which the oscillations settle out quickly. If the PB is too wide (insensitive), the offset will be much larger, reducing the

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amount of control over the process. Narrowing the PB (increasing the gain) can reduce the amount of offset, but too narrow a band will creates cycling.

Figure 2.1: Proportional Only System Response to a Process Upset with Different Proportional Band Widths

2.2 Proportional-Integral (PI) Control Integral action avoids the offset created in proportional control by bringing the output back to the set point. It is an automatic rebalancing of the system, which operates as long as an error exists. Therefore, integral control responds to the duration of the error as well as its magnitude and direction. Integral control is almost never used alone; rather, it is combined with proportional control.

Proportional-plus-integral (PI) control is generally used on processes where no amount of offset can be tolerated. Other applications include those where such a wide PB would be required for stability that the amount of offset created would be unacceptable. When a process upset occurs, the proportional controller registers an error and responds to it as shown in Figure 2.2. The integral control mode detects the offset error in the proportional mode and tries to eliminate the error.

In PI controller, integral action can be expressed in terms of minutes per repeat the amount of time necessary to repeat the response caused by the proportional mode for a step change in error. The smaller the time value, the faster the integral action. Some controller manufactures express integral action in repeats per minute, which is the reciprocal of minutes per repeat.

Ideally, the minutes per repeat chosen for the integral controller should bring the control point back to the set point quickly. If the integral time is too long, the system will not perform at maximum efficiency. If the time is too short, it will overshoot the set point and a continuous cycle may result.

One problem with integral control is that when a deviation cannot be eliminated over a period of time (as with batch processes when a tank is empty), the controller continues to see an error and tries to correct for it, saturating it and driving the output to its maximum value. This is called integral windup.

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Figure 2.2: PI Control System Response to a Process Upset with Different Integral Times

2.3 Proportional-Integral-Derivative (PID) Control The proportional and PI controller have limitations which may not be significant if the process and controller are carefully matched. However, some processes are so difficult to control or so critical to maintain at set point, that the use of all three modes will be helpful in maintaining desired control.

PID control responds to all aspects of process error direction, magnitude, duration and rate of change. The output of a PID controller is a linear combination of P, I, and D modes of control. PID control can be advantageous on many processes. Processes that benefit most from PID control have rapid and large disturbances in which derivative action can respond to the rapidity of the changes, and integral action can respond to the its duration.

Derivative action permits an increase in proportional gain, offsetting the decrease necessitated by integral action; where integral action tends to increase the period of cycling, derivative action tends to reduce it, thereby producing the same speed of response as with proportional action but without offset.

Figure 2.3 shows the effect of the addition of derivative action to a properly adjusted PI controller. The period (time to complete a cycle) is shorter than with PI-only control.

Figure 2.4 shows the response of a system to a process upset in the primary analogue control mode: proportional, integral, and PID.

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Figure 2.3: Comparison of System Response to a Process Upset with PI and PID Control

Figure 2.4: System Response to a Process Upset with Different Modes of Analogue Control

3.0 EQUIPMENT LEVEL CONTROL UNIT/TRAINER The Level Control Unit/Trainer consists of a process vessel connected to main reservoir with water pump, level sensor and electro-pneumatic proportional control valve (air supplied by a compressor). The liquid level rate is monitored by the sensor with digital signal output to the monitoring console at the computer.

An electronic controller is connected to the computer software for data logging and remote control. The proportional, PI and PID modes are preset into the system. The PID parameter may be continuously varied for optimum controller tuning. Demonstration of disturbance effect on the tank water level may be done with a disturbance valve to reduce the level in the tank.

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A - Process Tank Level Indicator

B - Process Tank

C - Pneumatic Pressure Regulator

D - Level Sensor

E - Water Pump

F - Control Panel

G - Electro-pneumatic Rotary Actuator with Positioner (proportional valve)

H - Reservoir Tank

I - Disturbance Valve

4.0 OPERATING PROCEDURE


1. Read and understand the theory of level process control. 2. Read and understand the equipment used in the experiment (level control unit). 3. Read the safety precautions before conducting the experiment.

4.2 General Start-Up Procedures

1. Fill the reservoir tank (H) with water to at least 3/4 of its maximum height. 2. Ensure that the disturbance valve (I) is in fully closed position. 3. Ensure that the pneumatic pressure regulator (C) is connected to the air compressor. Set the

pressure to 0.25 MPa ~ 0.3 MPa. 4. Ensure that the communication cable is connected from the side of the apparatuss control

panel (F) to computer PCI slot.

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1. Switch off the water pump (E). 2. Switch off the power at the control panel and the main power supply. 3. Turn off the compressed air supply valve at the compressor and switch off the compressor

main power supply.

5.0 SAFETY PRECAUTIONS

Do not switch on the water pump if there is no water in the reservoir tank or the water level is low.

Do not apply pressure more than 0.4 MPa to the electro-pneumatic proportional valve. Do not attempt to change the setting of the control valve and sensor. Switch off the apparatus if there is any water leakage.

6.0 EXPERIMENTS

Conduct the experiment with closed loop control without PID tuning and level value at 100 mm.

Reminder:

Click the Start button and save the file before turn on the water pump (E). WARNING: keep an eye on the process tank level indicator (A) on the right hand side of the equipment. Stop the pump immediately if the tank level reaches 250 mm to avoid tank overflow. Press Alt + Print Screen button on the computer keyboard and paste the graph in Paint or WordPad.

6.1 Experiment 1: Proportional-only (P) Mode Run the experiment with different P values (1 to 100).

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6.2 Experiment 2: Proportional-Integral (PI) Mode Run the experiment with different I values (0.05 to 2).

6.3 Experiment 3: Proportional, Integrative, Derivative (PID) Mode Run the experiment with different D values (0.05 to 2). Adjust all the three parameters to achieve the best system response.

7.0 RESULTS ANALYSIS AND DISCUSSIONS


Compare all the graphs obtained and explain the effect of the P, I and D action on the set-point selected. Figure out the system overshoot percentage and settling time.

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Experiment 5 Temperature Process Control


To understand the characteristic of proportional (P), proportional-integral (PI) and proportional-integral-derivative (PID) controller in a temperature control loop.

To observed the different types of temperature responses to P, PI and PID controller.

2.0 INTRODUCTION


2.1 On/Off Control

On/Off control is generally both the simplest and the least expensive type of process, but response of an on/off controller almost always has some error in it. The controller turns on or off only when the measurement crosses its set point on its way from one extreme error to another. At that point, the valve goes either fully open (on) or closed (off), depending on the direction of the error. The size of the error is not recognised and the energy or material supplied to the process is always either too much or not enough. The measured variable also cycles continuously. On/Off control best applied to a large capacity process that has relatively little dead time and a small mass or energy inflow with respect to the capacity of the system.

Figure 2.1: System Response to a Process Upset with ON/OFF Control

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Curve C in Figure 2.2 shows system response when the proportional band in which the oscillations settle out quickly. If the PB is too wide (insensitive), the offset will be much larger, reducing the amount of control over the process. Narrowing the PB (increasing the gain) can reduce the amount of offset, but too narrow a band will creates cycling.


2.3 Proportional-Integral (PI) Control Integral action avoids the offset created in proportional control by bringing the output back to the set point. It is an automatic rebalancing of the system, which operates as long as an error exists. Therefore, integral control responds to the duration of the error as well as its magnitude and

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direction. Integral control is almost never used alone; rather, it is combined with proportional control.





2.4 Proportional-Integral-Derivative (PID) Control PID control responds to all aspects of process error direction, magnitude, duration and rate of change. The output of a PID controller is a linear combination of P, I, and D modes of control. PID control can be advantageous on many processes. Processes that benefit most from PID control have rapid and large disturbances in which derivative action can respond to the rapidity of the changes, and integral action can respond to the its duration.


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2.5 Control Loop Tuning

Tuning process adjusts the controlled variable to the set point so it can achieve that balance as quickly as possible. This is done when the instrument is first put in service and, later, on a periodic basis, tune as part of preventive maintenance. When tuning, remember that each controller is part of a closed loop: all the parts of the loop are interactive. The controller response must be matched

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to that of the process. There are several procedures for doing this, some mathematical, most using trial and error.

3.0 EQUIPMENT TEMPERATURE CONTROL UNIT/TRAINER The Temperature Control Unit/Trainer consists of a heat exchanger with two input/output ports for hot and cold water as the medium. Water is heated by a submersion heater in the hot water tank and is circulated in the system by pump P1. Cold water, supplied by the cold water tank which connects directly to a water supply, is pump into the heat exchanger by pump P2 and then discharge into drain.

Temperature transmitter TT01 is used to measure the cold water outlet temperature from the heat exchanger and is linked to a microprocessor based controller. The controller output is linked to a pneumatic control valve (air supplied by a compressor) to manipulate the hot water flow rate into the heat exchanger which will affect the cold water outlet temperature.

The unit is supplied with a chart recorder. The pump has its own starter. The control panel and patch panel are safely protected against water splashes.

Figure 3.1: Schematic Diagram of Temperature Control Unit / Trainer

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1. Read and understand the theory of temperature process control. 2. Read and understand the equipment used in the experiment (temperature control unit). 3. Read the safety precautions before conducting the experiment.


1. Switch ON the computer and start the temperature control unit software (SE-404). 2. Ensure that all valves are set according to the position outlined in table below:

Open Close Partially Open HV1

(hot water pump inlet) HV3

(cold water tank drain valve) HV2

(hot water pump bypass) HV6

(cold water pump inlet) HV4

(hot water tank drain valve) HV7

(cold water pump bypass) HV9

(cold water discharge to drain) HV5

(hot water tank supply valve)

HV10 (cold water tank supply valve)

3. Fill up Tank TN1 and TN2 with water by opening valve HV5 and HV10 until the tanks are full. Close valve HV5 and leave valve HV10 open.

4. Turn on the power supply and main power switch at the front of the control panel 5. Turn on the water heater. 6. Set the temperature controller TIC 02 set point to 55C and wait until the temperature reaches

55C (temperature of hot water tank). 7. Switch on Pump P2 and adjust the flow rate to ~ 5 LPM by using valve HV8. 8. Turn on the hot water circulation pump P1. 9. The unit is now ready.


1. Switch off pump P1, P2 and water heater E1. 2. Switch off the power at the control panel and the main power supply. 3. Turn off the compressed air supply valve at the compressor and switch off the compressor

main power supply. 4. Turn off the main water supply.

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Do not switch on the water pump if there is no water in the tank or the water level is low. Do not apply pressure more than 0.4 MPa to the electro-pneumatic proportional valve. Do not attempt to change the setting of the control valve and sensor. Switch off the apparatus if there is any water leakage.

6.0 EXPERIMENTS

6.1 Experiment 1: Closed Loop Proportional (P) Control 6.1.1 Load Change

Simulate a load change by increasing the cold water flow rate for 20 seconds by using valve HV8. Repeat the experiment with Three different PB values while keeping the I and D values constant.

Reminder:

Start with Manual Mode where Proportional (PB) value of 100, Integral (I) value of 600 seconds and Derivative (D) value of 0 second. Set the Set Point value and slowly adjust the control valve opening until the Process Value matches the Set Point. Let the system stabilise for 5 minutes.

Then continue with Auto Mode where at Data Logging, click New and then Record. Set the time interval and check the box Auto. When the cold water outlet temperature (TIC 01) become constant for about 15 readings, stop the recording by un-checking the box Auto and save the data. Go to Trend, set the x-axis duration and print the graph (to PDF format).

6.1.2 Set Point Change

Conduct the experiment as in section 6.1.1 but change the Set Point value and fix the flow rate.

6.2 Experiment 2: Closed Loop Proportional-Integral (PI) Control Run experiment by changing the I values while keeping the PB and D values constant.

6.3 Experiment 3: Closed Loop Proportional-Integral-Derivative (PID) Control Run experiment by changing the D values while keeping the PB and I values constant.

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Comment on the differences in terms of controller mode (P, I and D) set values, offsets, response times and response behaviours. Figure out the system overshoot percentage and settling time.

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Experiment 6 Pressure Process Control


To understand the characteristic of proportional (P), proportional-integral (PI) and proportional-integral-derivative (PID) controller in a pressure control loop.

To observed the different types of process pressure responses to P, PI and PID controller. To determine the optimum controller tuning parameter(s) for P, PI and PID controller.

2.0 INTRODUCTION








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3.0 EQUIPMENT PRESSURE CONTROL UNIT/TRAINER The Pressure Control Unit/Trainer consists of a gas vessel connected to main reservoir vessel, pressure sensor and electro-pneumatic proportional control valve (air supplied by a compressor). The air pressure reading is continuously monitored by the pressure sensor with digital signal output to the monitoring console at the computer.

An electronic controller is connected to the computer software for data logging and remote control. The proportional, PI and PID modes are preset into the system. The PID parameter may be continuously varied for optimum controller tuning. Demonstration of disturbance effect on process pressure may be done with a disturbance valve to reduce the pressure of the vessel.

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A - Safety Valve

B - Process Tank

C - Pneumatic Pressure Regulator

D - Pressure Sensor

E - Inlet Valve

F - Control Panel

G - Electro-pneumatic Rotary Actuator with Positioner (proportional valve)

H - Reservoir Tank

I - Disturbance Valve

4.0 OPERATING PROCEDURE


1. Read and understand the theory of pressure process control. 2. Read and understand the equipment used in the experiment (pressure control unit). 3. Read the safety precautions before conducting the experiment.


1. Ensure that the inlet valve (E) is in fully closed position. 2. Ensure that the disturbance valve (I) is in fully closed position. 3. Ensure that the pneumatic pressure regulator (C) is connected to the air compressor. Set the

pressure to 0.25 MPa ~ 0.3 MPa. 4. Ensure that the communication cable is connected from the side of the apparatuss control

panel (F) to computer PCI slot.

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1. Switch off the power at the control panel and the main power supply. 2. Turn off the compressed air supply valve at the compressor and switch off the compressor

main power supply. 3. Release all the pressure from both the Process Tank (B) and Reservoir Tank (H) by using the

Safety Valve (A) or Disturbance Valve (I).


Do not apply pressure more than 0.4 MPa to the electro-pneumatic proportional valve and the system tanks.

Do not attempt to change the setting of the control valve and sensor.

6.0 EXPERIMENTS

Conduct the experiment at closed loop control option where the controller under an idle mode and set value is between 1.5 to 2.5 bar.

Reminder:

Click the Start button and save the file. Open the inlet valve E to allow the compressed air to flow into the process tank. Allow the system to reach steady state (where the response has stabilised). Press Alt + Print Screen button on the computer keyboard and paste the graph in Paint or WordPad.

Press the Stop button and close the inlet valve E.

6.1 Experiment 1: Proportional-only (P) Mode Input the set point. Repeat the experiment with different P values (1 to 100) and different set points.

6.2 Experiment 2: Proportional-Integral (PI) Mode Run the experiment by introducing different I value (0.05 to 2).

6.3 Experiment 3: Proportional, Integrative, Derivative (PID) Mode Run the experiment by introducing different D value (0.05 to 2). Adjust all the three parameters to

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achieve the best system response. The control system must be able to eliminate any offset.

7.0 RESULTS ANALYSIS AND DISCUSSIONS

Discuss all your results.

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Experiment 7 Flow Process Control


To understand the characteristic of proportional (P), proportional-integral (PI) and proportional-integral-derivative (PID) controller in a flow control loop.

To observed the different types of process flow rate responses to P, PI and PID controller. To determine the optimum controller tuning parameter(s) for P, PI and PID controller.

2.0 INTRODUCTION








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3.0 EQUIPMENT FLOW CONTRO

lab manual 2013-r1

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