Sample Lab Reportlj

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EXPERIMENT: 1| (SECTION 02) 2

TABLE OF CONTENT

NUM CONTENTS PAGE

1.0 Abstract

2.0 Introduction

1.1Experimental background1.2Objective1.3Experimental scope

3.0 Theory/Literature Study

4.0 Methodology3.1 Equipment and Materials

3.2 Experimental procedure/methodology

5.0 Result and Discussion

4.1Experimental data

4.2 Data analysis and discussion

4.3 Answer to the question in the experimental module

6.0 Conclusion

7.0 References

8.0 Appendices


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1.0 ABSTARCT

This experiment is carried out to understand the CSTR system, study the use of a CSTR and

the effects of flow changes. Other significance of doing this experiment is to determine rate

constant from data and also to study the temperature effects for reaction. The real objective of

conducting the experiment is to study the reaction process of saponification reaction between

sodium hydroxide and ethyl acetate in CSTR.

The first things before all the apparatus is set-up, the conductivity calibration curve is

prepared using different molar concentration of sodium hydroxide and sodium acetate. This

calibration curve can be used to determine the reaction kinetics and the rate law of the process.

Then, both sodium hydroxide and ethyl acetate is prepared according to the given volume and

molar concentration before it is transferred into the tank. When the process started, the

conductivity and temperature of the reaction is recorded for every two minutes for over 30

minutes. The space time as well as the conductivity and the temperature of the reaction

medium are recorded when the liquid level in the CSTR reach two litres. After flow the

reaction into the buffer tank, the readings are recorded for another ten minutes. The process

are repeated for different amount of feed flow rates.

Based on methodology section in the report, it tells about the steps involved while conducting

the experiment while the results section shows the recorded value of conductivity and

medium reaction temperature. In addition, it also shows the calculated concentrations of the

input and output chemicals, rate of reaction and theoretical space time of the CSTR. Instead

of that, the discussion section shows the graph plotted using the result obtained and discussed

it more detail based on chemical reaction engineering theory. The error and recommendation

to avoid mistakes while doing the experiment is also shared in the discussion. The conclusionsection concludes all the objectives and calculations of this experiment.


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2.0 INTRODUCTION

A common type of reactor used in industrial processing is the continuous-stirred tank reactor

(CSTR) which is used primarily for liquid phase reaction. It is normally operated at steady

state and assumed to be perfectly mixed. Usually there is no time dependence or position

dependence of the temperature, the concentration or the reaction rate inside the tank. This

means that every variable is the same inside the reactor. Because the compositions of

mixtures leaving a CSTR are those within the reactor, the reaction driving forces, usually the

reactant concentrations, are necessarily low. Therefore, except for reaction orders zero- and

negative, a CSTR requires the largest volume of the reactor types to obtain desired

conversions. However, the low driving force makes possible better control of rapid

exothermic and endothermic reactions. When high conversions of reactants are needed,

several CSTRs in series can be used. Equally good results can be obtained by dividing a

single vessel into compartments while minimizing back-mixing and short-circuiting. The

larger the number of CSTR stages, the closer the performance approaches that of a tubular

plug-flow reactor.

Figure shows Continuous stirred tank reactors, (a) With agitator and internal heat

transfer surface, (b) With pump around mixing and external heat transfer surface.

This experiment was conducted to study the saponification reaction between sodium

hydroxide and ethyl acetate in a continuous-stirred tank reactor (CSTR). The saponification

process is a process that produces soap, usually from fats and lye. In technical terms,

saponification involvesbase (usuallycaustic sodaNaOH)hydrolysis of triglycerides,which

areesters of fatty acids, to form the sodiumsalt of acarboxylate.
http://en.wikipedia.org/wiki/Reaction_orderhttp://en.wikipedia.org/wiki/Soaphttp://en.wikipedia.org/wiki/Lyehttp://en.wikipedia.org/wiki/Base_%28chemistry%29http://en.wikipedia.org/wiki/Caustic_sodahttp://en.wikipedia.org/wiki/Hydrolysishttp://en.wikipedia.org/wiki/Triglyceridehttp://en.wikipedia.org/wiki/Esterhttp://en.wikipedia.org/wiki/Salt_%28chemistry%29http://en.wikipedia.org/wiki/Carboxylatehttp://en.wikipedia.org/wiki/Carboxylatehttp://en.wikipedia.org/wiki/Salt_%28chemistry%29http://en.wikipedia.org/wiki/Esterhttp://en.wikipedia.org/wiki/Triglyceridehttp://en.wikipedia.org/wiki/Hydrolysishttp://en.wikipedia.org/wiki/Caustic_sodahttp://en.wikipedia.org/wiki/Base_%28chemistry%29http://en.wikipedia.org/wiki/Lyehttp://en.wikipedia.org/wiki/Soaphttp://en.wikipedia.org/wiki/Reaction_order


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Instead of carry out the saponification process as the scope of the experiment, it also

conducted to identify the CSTR system and investigate its operational behavior of a reaction

in it, to calculate the reactant conversion based on the conductivity calibration curve and to

verify the reaction order obtained from the hypothesis of the experiment using graphical and

analytical techniques. The results from both techniques are compared. Besides that, the

significance of doing this experiment is to determine the rate constant of saponification

reaction by using both techniques again. In fact, the experiment is carry out to scale-up the

reactor for large scale production and to compare the kinetic reaction, rate law and

conversion in a CSTR to the one in a batch reactor system for the same reaction.

The reaction kinetics and rate law of saponification reaction in a CSTR can be determined

using conductivity calibration curve. Conductivity is a measure of how well a solution

conducts electricity. To carry a current a solution must contain charged particles, or ions.

Most conductivity measurements are made in aqueous solutions, and the ions responsible for

the conductivity come from electrolytes dissolved in the water. Salts like sodium chloride and

magnesium sulfate), acids (like hydrochloric acid and acetic acid), and bases (like sodium

hydroxide and ammonia) are all electrolytes. Although water itself is not an electrolyte, it

does have a very small conductivity, implying that at least some ions are present. The ions are

hydrogen and hydroxide, and they originate from the dissociation of molecular water.

There are two ways to calibrate conductivity sensors. The sensor can be calibrated against a

solution of known conductivity or it can be calibrated against a previously calibrated sensor

and analyser. Normally, the sensor should be calibrated at a point near the midpoint of the

operating range calibration changes the cell constant. In this experiment, the calibration curve

is prepared using different molar concentration of sodium hydroxide and sodium acetate.


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3.0 LITERATURE REVIEW

In the industrial, two type of the reactor that always used are continuous stirred-tank

reactor (CSTR) and packed bed reactor (PBR). The CSTR reactor will operate at the steady

state. The process of the reactants into the reactor bribes and spending is the product of the

reactor along the reactor operates continues. As a whole, the reactor was stirred continues

mixed perfect and there is no distinction in the overall density and temperature in the reactor.

This assumption may be made namely the concentration and temperature is identified in all

regions of the reactor is equal to the temperature and density at the reactor output. Another

advantage of this continuous stirred reactor is a reactor of this type has the ability to escort the

temperature and pressure.


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4.0 METHODOLOGY

A. Calibration graph plot

1. Conductivity calibration curve is prepared using three points:

i. X = 0.0, use 10mL 0.1M NaOH

ii. X = 0.5, use a mixture of 5 mL NaOH and 5 mL sodium acetate

iii. X = 1.0, use 10 mL 0.1M sodium acetate

B. Operating procedure

1. 9L solution of 0.1M NaOH (8g per 2L H2O) and 9L solution of 0.1M EA (19.6mLper 2L H2O) are prepared and these solutions were poured into T1 and T2

respectively.

2. Pumps P1 and P2, and stirrer S1 are switched on. The feed flow rates into the CSTRare adjusted to be at 40 cm3/min using valves F1 and F2. The stopwatch was started

immediately as the pumps and stirrer were switched on. The conductivity and

temperature of the reaction medium in the CSTR were measured for every 2 minutes

for over 30 minutes.

3. When liquid level inside the CSTR reached 2000cm3 (2L), the space time,conductivity and temperature of the reaction medium were recorded.

4. Then, the reaction is flowed into the buffer tank by opening valve V3. Measurementswere continued taken for 10 minutes.

5. When 30 minutes of reaction is over, valves F1 and F2 were closed, and pumps P1and P2 were stopped. All liquids were discharged through valve V4.

6. The experiment was repeated for different feed flow rates: 60, 100 and 120 cm3/min.7. Once the experiments were done, all residual NaOH and EA were discharged.8. The pilot plant was cleaned up.


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Table 4 Experimental data: flow rate = 100cm3/min

Time,

t (min)

Conductivity

Temp.

(oC)

Conversion

(mol)

CA(mol/L)

CB(mol/L)

CC(mol/L)

CD

(mol/L)

1/rAx10-

0 12.9 27.0 0.251 0.0749 0.0749 0.0251 0.0251 1.2550

2 11.0 27.1 0.448 0.0552 0.0552 0.0448 0.0448 2.24004 14.2 27.2 0.115 0.0885 0.0885 0.0115 0.0115 0.0575

6 12.2 27.0 0.323 0.0677 0.0677 0.0323 0.0323 1.6150

8 11.80 27.2 0.365 0.0635 0.0635 0.0365 0.0365 1.8250

10 11.47 27.3 0.399 0.0601 0.0601 0.0399 0.0399 1.9950

12 9.75 27.3 0.578 0.0422 0.0422 0.0578 0.0578 2.8900

14 9.42 27.3 0.613 0.0387 0.0387 0.0613 0.0613 3.0650

16 9.19 27.3 0.637 0.0363 0.0363 0.0637 0.0637 3.1850

18 9.08 26.7 0.648 0.0352 0.0352 0.0648 0.0648 3.2400

20 9.51 27.5 0.603 0.0392 0.0392 0.0603 0.0603 3.0150

22 9.47 27.4 0.607 0.0393 0.0393 0.0607 0.0607 3.0350

Table 5 Experimental data: flow rate = 120cm3/min

Time,

t (min)

Conductivity

Temp.

(oC)

Conversion

(mol)

CA(mol/L)

CB(mol/L)

CC(mol/L)

CD

(mol/L)

1/rAx10-

0 12.06 27.1 0.338 0.0662 0.0662 0.0338 0.0338 1.4083

2 9.29 27.3 0.626 0.0374 0.0374 0.0626 0.0626 2.6083

4 10.71 27.4 0.478 0.0522 0.0522 0.0478 0.0478 1.9917

6 11.43 27.3 0.404 0.0596 0.0596 0.0404 0.0404 1.6833

8 11.24 27.4 0.423 0.0577 0.0577 0.0423 0.0423 1.7625

10 10.57 27.3 0.493 0.0507 0.0507 0.0493 0.0493 2.054212 10.57 27.1 0.493 0.0507 0.0507 0.0493 0.0493 2.0542

14 10.44 27.1 0.507 0.0493 0.0493 0.0507 0.0507 2.1125

16 10.35 27.1 0.516 0.0484 0.0484 0.0516 0.0516 2.1500

18 10.48 26.8 0.502 0.0498 0.0498 0.0502 0.0502 2.0917

20 10.33 27.6 0.518 0.0482 0.0482 0.0518 0.0518 2.1583

Table 6 Experimental data: space time

Flowrate

vo

(cm

3

/min)

Theoretical

Space time

(min)

Actual

Space time

(min)

Conductivity

Temp.

(oC)

Conversion

X

(mol)

40 50.00 20 9.91 26.2 0.562

60 33.33 18 7.65 27.1 0.797

100 25.00 12 9.75 27.3 0.578

120 16.67 10 10.57 27.3 0.493


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