Jawaharlal Nehru Engineering College

Transcription

1 Jawaharlal Nehru Engineering College Laboratory Manual CHEMICAL REACTION ENGINEERING For Third Year Students Chemical Engineering 16, Dec 2003 Rev 00 Chem Engg. ISO 9000 Tech Document Author JNEC, Aurangabad

2 FORWARD It is my great pleasure to present this laboratory manual for Final year engineering students for the subject of Chemical Reaction Engineering keeping in view the vast coverage required for visualization of concepts of Industrial Pollution Control with simple language. As a student, many of you may be wondering with some of the questions in your mind regarding the subject and exactly what has been tried is to answer through this manual. As you may be aware that MGM has already been awarded with ISO 9000 certification and it is our endure to technically equip our students taking the advantage of the procedural aspects of ISO 9000 Certification. Faculty members are also advised that covering these aspects in initial stage itself, will greatly relived them in future as much of the load will be taken care by the enthusiasm energies of the students once they are conceptually clear. Principal

3 LABORATORY MANNUAL CONTENTS This manual is intended for the Third year students of Chemical Engineering branch in the subject of Chemical Reaction Engineering. This manual typically contains practical/lab Sessions related Reaction Engineering covering various aspects related to the subject to enhance understanding. We have made the efforts to cover various aspects of the subject Chemical Reaction Engineering in chemical industry to make it meaningful, elaborative understandable concepts and conceptual visualization. Students are advised to go thoroughly through this manual rather than only topics mentioned in the syllabus as practical aspects are the key to understanding and conceptual visualization of theoretical aspects covered in the books. Good Luck for your Enjoyable Laboratory Sessions

4 SUBJECT INDEX 1. Interpretation of batch reactor data. 2. To study the kinetics of liquid phase irreversible reaction in a batch reactor. 3. To study the kinetics of liquid phase reversible reaction in batch reactor. 4. Conversation in CSTR. 5. Conversation in PFR. 6. Saponification of Ethyl Acetate 7. To determine the pseudo first order rate constant. (TBC) 8. To study the kinetics of liquid phase reaction by dilatometer method.

5 DOs and DON T DOs in Laboratory: 1. Do not enter the laboratory without wearing apron, preferably use shoes. 2. Safety should be given topmost priority. 3. Follow the instructions given by the teacher. 4. Do not touch any Equipment/Chemicals without prior permission. 5. Check the glassware before getting issued. 6. Handle the chemicals carefully as per instructions. 7. Do not pipette any solution/chemical with mouth. 8. During performance of the practical if any glassware is broken inform immediately. 9. Return the borrowed apparatus after the expt is over. 10. Observe safety precautions while performing the expts. Instruction for Laboratory Teachers:: 1. Submission related to lab work completed, should be done before the next lab session. 2. The promptness of submission should be encouraged by way of marking and evaluation patterns that will benefit the sincere students. WARMUP EXCERCISES: Define Reaction Rate, Rate constant, Activation Energy, Space Time, Space Velocity, Molecularity, Order Of Reaction, Equation Representing Batch Reactor, CSTR, PFR Different Types of Industrial Reactors, Different Application of Chemical Reaction Engineering.

6 Exercise No1: ( 2 Hours) Interpretation of Batch Reactor data A] Aim: To study the interpretation of Batch Reactor Data. Theory: -- 1) Integral Method of Analysis: 2) Differential Method of Analysis: --- Conclusion--

7 Exercise No2: ( 2 Hours) Batch Reactor for irreversible reaction. A] Aim: To study batch reactor kinetics for ethyl acetate - NaOH and find the value of rate constant. Procedure: 1) Take the solution of NaOH (0.1N) and ethyl acetate (0.1N) of desired concentration inside the batch reactor. 2) The mixture in the reactor is continuously stirred and the stirred is maintained at constant speed 3) Take out sample in a beaker from reactor at constant time difference. 4) Add 20ml of 0.1N HCL in the sample. 5) Titrate the sample against 0.1N NaOH using phenolphthalein as an indicator. 6) Repeat the above procedure six times. Observations: 1) Normality of NaOH solution (N3) = 0.1N 2) Normality of Ethyl acetate solution = 0.1N 3) Normality of HCL solution (N1)= 0.1 N 4) Volume of HCL solution (V1)= 20 ml 5) Volume of NaOH (V3) in burette 6) Volume of sample (V2) = 10 ml Observation Table: Sr.No Time (Sec.) Vol.of NaOH (ml) Normality CA = N2 XA -Ln (1-XA) Calculations: CA= N2 =N1V1-N3V3 / V2 From graph of -Ln (1-XA) Vs Time Calculate the slope K (Sec -1 ) Result:

8 Exercise No3: ( 2 Hours) Batch Reactor for rreversible reaction. A] Aim: To study batch reactor kinetics for Acetic acid - Methanol and find the value of rate constant. Procedure: 1) Take the solution of Acetic acid (0.1 N) - Methanol (0.1 N) of desired concentration inside the batch reactor. 2) The mixture in the reactor is continuously stirred and the stirred is maintained at constant speed 3) Take out sample in a beaker from reactor at constant time difference. 4) Titrate the sample against 0.1N NaOH using phenolphthalein as an indicator. 5) Repeat the above procedure six times. Observations: 1) Normality of NaOH solution (N1) = 0.1N 2) Normality of Acetic acid solution = 0.1N 3) Normality of Methanol solution = 0.1 N 4) Volume of NaOH (V1) in burette 5) Volume of sample (V2) = 10 ml Observation Table: Sr.No Time (Sec.) Vol.of NaOH (ml) Normality CA = N2 XA -Ln (1-XA) Calculations: CA= N2 =N1V1 / V2 CA = CA0-CA/CA0 From graph of -Ln (1-XA) Vs Time Calculate the slope K (Sec -1 ) Result:

9 Exercise No4: ( 2 Hours) Continuous stirred tank reactor A] Aim: To carry out saponification of ethyl acetate in given CSTR and to determine the conversion and to compare with the theoretical Procedure: 1) Standardized solution of 0.1 N ethyl acetate, 0.1 N NaOH and 0.1 N HCL are used. 2) The observed tanks are filled with NaOH and ethyl acetate solution. 3) The mixture in the reactor is continuously stirred and the speed of the stirrer is maintained at constant value. 4) Determine the residence time in the reactor by starting the flow of NaOH solution and measuring the flow rate with rotameter (Vol of reactor/volumetric flow rate = m 3 /sec or liters/lpm) 5) Start the flow of ethyl acetate and check that its flow rate is also the same as of NaOH and such that ample time is allowed for the reaction to reach steady state (Approximately 10 times the residence time)) 6) Take 20 ml of 0.1 N HCL in a flask and add 10 ml of reaction mixture (from outlets) to the flask. 7) Back titrate the mixture in the flask with 0.1 N NaOH using phenolphthalein as an indicator 8) Take five more samples from reacting streams Observations: 1) Standardization NaOH solution 2) Standardization HCL solution 3) Normality of NaOH solution = N 4) Normality of HCL solution = N1 5) Normality of NaOH solution used for back titration = N3 6) Reactor Volume = V 7) Volume of sample collected = V2 8) Volume of HCL taken = V1 9) Volume of NaOH rundown in back titration = V3 10) Concentration of A (i.e. Ethyl Acetate) can be calculated as CA = N1V1 N3V3 / V2 Observation Table: Sr.No Flow Rate of ethyl acetate (LPM) Flow Rate of NaOH (LPM) Sample Collected V2 (ml) NaOH V3 (ml) Time (Sec.) Calculations: F = FA+FB/2 Initial concentration of A = CA0 = FA *N (EA) / FA+FB N (EA) =Normality of ethyl acetate CB = (CB0-CA0) +CA Where CB0 = FB *N (NaOH) / FA+FB And Reaction rate ra =F (CA0-CA)/V

10 XA = CA0-CA/CA0 Prepare a table as follows: Sr.No. CA0 CB0 CA CB XA Result: 1) Report the values of residence times in the reactor. 2) Report the values of average conversion for saponification of ethyl acetate

11 Exercise No5: ( 2 Hours) 1 Practical Plug Flow Reactor A] Aim: To carry out saponification of ethyl acetate in given PFR and to determine the conversion experimentally Procedure: 1) Start the flow rate to achieve steady-state condition. (Flow rate of NaOH) 2) Then start the flow rate of ethyl acetate and ensure NaOH as well as ethyl acetate flow rate are at steady state. 3) Take 20 ml sample of mixture and add 20 ml of 0.1 N HCL and then titrate with NaOH (0.1 N) 4) Continue taking reading until constant burette reading is obtained (at least 10 readings) 5) Find the practical conversion of PFR Observations: 1) Normality of NaOH solution (N3)= 0.1N 2) Volume of NaOH (Burette Reading, V3) = 3) Normality of Ethyl acetate solution = 0.1N 4) Normality of HCL solution (N1)= 0.1 N 5) Volume of HCL solution (V1) = 6) Volume of sample (V2) = - 7) Reactor Volume = ml 8) Flow rate of NaOH solution = LPM 9) Flow rate of Ethyl acetate solution = LPM Observation Table: Sr.No Time (Sec.) Burette Reading (ml) XA Calculations: Limiting reactant is ethyl acetate N2 = N1V1 N3V3 / V2 N2 = Normality of unreacted NaOH CA = CA0 (M-X=) = CA0 (CB0 /CA0 XA) N2 = CA0 (CB0 /CA0 XA) Hence calculate XA i.e. practical conversion. Result: Practical conversion in PFR =

12 Exercise No6: ( 2 Hours) Saponification of Ethyl Acetate A] Aim: To determine that the saponification of ethyl acetate in dilute aqueous solution is a second order reaction and to report the value of the reaction rate constant. Procedure: 1) Prepare 0.1 N NaOH solution 2) Place 400 ml of alkali solution in a clean 1 lit. Flask, which serve as a reactor. Add 25 ml of HCL (0.1 N) solution in to each of 1,2,3.Flask 3) Place the reactor on a magnetic stirrer and start stirring vigorously. Keep a clean and dry 25 ml pipette handy. 4) By using pipette transfer exactly 1.96 ml of ethyl acetate solution in to the reactor and start stopwatch simultaneously. The ethyl acetate itself forms a 0.05 M solution. in a rector itself and the saponification reaction is now on. 5) At a reaction time of 1,2,3. 12 min. pipette out 25 ml of reaction mixture into each one of the labeled conical flask. 6) Back titrate the content of the 12 conical flasks with NaOH using phenolphthalein as an indicator. Observations: 1) Standardization NaOH solution 2) Standardization HCL solution 3) Standardization Ethyl acetate solution 4) Normality of NaOH solution (N3) = N 5) Volume of NaOH solution (V3) = 6) Normality of HCL solution (N1) = 7) Volume of HCL solution (V1)= 8) Volume of reaction mixture (V2)= Observation Table: Sr.No Time Sec Volume of NaOH (ml) CA 1/CA CA 2 -dca/dt Calculations: N2 = CA = N1V1 N3V3 / V2 Graphs: 1) CA Vs Time 2) dca/dt Vs CA 2 3) 1/CA= Vs Time Result:

13 Exercise No7: ( 2 Hours) Hydrolysis of tertiary butyl chloride A] Aim: To determine the pseudo first order rate constant for the hydrolysis of TBC Chemicals required: Solution of TBC in acetone of 0.1N,NaOH solution of 0.05 N, bromophenol blue indicator,250 ml conical flasks, measuring pipette, stop watch, distilled water, standardized oxalic acid Procedure: 1) Pipette precisely 3ml of 0.1 N TBC into a clean and dry 25 ml conical flask (1) 2) Pipette precisely 0.6ml of 0.05 N NaOH into another clean and dry 25 ml conical flask (2).To this add 6.4 ml of distilled water by means of pipette (Use different pipettes for different solutions) 3) Add a drop of bromophenol indicator into flask (No.2). This will give a deep blue indication. Observe the color by placing it on a tile or a plain paper 4) Add contents of flask (2) to flask (1) starting the stopwatch simultaneously mix the solution thoroughly and then pour it back to flask (2) and watch for change of color 5) When the solution color changes from deep blue to greenish yellow stop the stopwatch and note the time. 6) Repeat the experiment with different quantities of NaOH 7) Determine the exact normality of NaOH solution before starting the experiment the experiment. The value of the fraction of conversion XA depends on exact normality of NaOH solution 8) Note the room temperature Observations: Normality of NaOH solution = N Normality of TBC = N Observation Table: Sr.No Volume of TBC (ml) Volume of NaOH (ml) Volume of water (ml) Time Sec XA Ln [1/1-XA] Calculations: XA = NNaOH * VNaOH / NTBC * VTBC CB0 = Concentration of H2O= gmmole /lit ln[1/1-xa] Slope = k time (sec) k I = k / CB0 6) Result: The pseudo first order rate constant = k= 7) The pseudo second order rate constant = k I =

14 7. Quiz on the subject: Quiz should be conducted on tips in the laboratory, recent trends and subject knowledge of the subject. The quiz questions should be formulated such that questions are normally are from the scope outside of the books. However twisted questions and self formulated questions by the faculty can be asked but correctness of it is necessarily to be thoroughly checked before the conduction of the quiz. 8. Conduction of Viva-Voce Examinations: Teacher should oral exams of the students with full preparation. Normally, the objective questions with guess are to be avoided. To make it meaningful, the questions should be such that depth of the students in the subject is tested Oral examinations are to be conducted in co-cordial environment amongst the teachers taking the examination. Teachers taking such examinations should not have ill thoughts about each other and courtesies should be offered to each other in case of difference of opinion, which should be critically suppressed in front of the students. 9. Submission: Document Standard: A] Page Size A4 Size B] Running text Justified text C] Spacing 1 Line D] Page Layout and Margins (Dimensions in Cms) Normal Page Horizantal

15 Desription Font Size Boldness Italics Underline Capitalize College Name Arial Yes Document Title Tahoma Document Subject Century Gothic Capital Class Bookman old Slyle Document No Bookman old Slyle Copy write inf Bookman old Slyle Forward heading Bookman old Slyle Yes Capital Forward matter Bookman old Slyle Lab man Contents title Bookman old Slyle Yes Capital Index title Bookman old Slyle 12 Yes Yes Capital Index contents Bookman old Slyle Heading Tahoma 14 Yes Yes Yes Running Matter Comic Sans MS Evaluation and marking system: Basic honesty in the evaluation and marking system is absolutely essential and in the process impartial nature of the evaluator is required in the examination system to become popular amongst the students. It is a wrong approach or concept to award the students by way of easy marking to get cheap popularity among the students to which they do not deserve. It is a primary responsibility of the teacher that right students who are really putting up lot of hard work with right kind of intelligence are correctly awarded. The marking patterns should be justifiable to the students without any ambiguity and teacher should see that students are faced with unjust circumstances.

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