cstr 40 L

CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] ABSTRACT: Based on the tittles, we had done this experiment in order to fulfil the syllabus of Chemical Engineering Laboratory subject. Thus, we had to know more detail about the Continuous Stirrer Tank Reactor (CSTR) 40 L and we had to carry out the operation for the saponificaton of NaOH and Et(Ac). This experiment had been done to achieve the objectives that had been considered which are to determine the effect of the residence time onto the reaction extend of conversion, to carry out a saponification reaction between NaOH and Et (Ac) in a CSTR and lastly to determine the reaction rate constant for the reaction in continuous stirrer tank reactor (CSTR). This experiment used model BP 143 as the mechanism to run the reaction. We conducted the experiment on 12nd April 2013 at Pilot Plant Laboratory, UiTM Shah Alam. Based on the processing, we had been divided into 2 groups which first group prepare the calibration curve for the saponification between NaOH and Et (Ac) while the other one is running the machine in order to determine the effect of the residence time onto the reaction. Before we started, we ensured that all the general start up was carried out properly according to the consultation before with lab assistant, Mr Jamil in order to avoid any disturbance that may affect our result. After the methodology for general start up settled, we continued by start up the experiment by open fully V5 and V10 to obtain adjustable flow rate which are 0.15, 0.20, 0.25 and 0.30. For each flow rate, 100 mL of the sample are collected at V12 that used in the back titration. Then, the stable conductivity is recorded into a data for every 5min before collect the samples. In the back titration, the samples that had been collected are titrated with NaOH for saponification reaction until it change colour from colourless into light pink. Then, the amount of NaOH titrated were recorded. From the tabulated data, a few of calculation are carried out and graph had been plotted.

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] INTRODUCTION: Based on all industrial sector, mostly reactor is the main equipment that are used where it changes from the raw materials into the desire product that are needed. The criteria for the good reactor is it produced a high production and also economical. There are many types of reactor depending on the nature of the feed materials and products. The rate of reaction is the most important thing that we are considered in the reactor because it showed the effectiveness of the processing of the reactor. A most common ideal reactor type in chemical engineering is the continuous stirred tank reactor or known as CSTR. In a continuous stirred tank reactor (CSTR), reactants and products are continuously added and withdrawn from the reactor. The CSTR is the idealized opposite of the weel-stirred batch and tubular plug flow reactors. Analysis of selected combination of these reactors types can be useful in quantitatively evaluating more complex gas-, liquid-, and solid-flow behaviours. Furthermore, the continuous stirred tank reactor (CSTR) which is also known as vat-or backmix reactor and this kind of model used to estimate the key unit operation variables when using a continuous agitated-tank reactor to reach a specified output. This reactor can be used for all fluids, gases and slurries. In a perfectly mixed reactor, thus the output composition is identical to the composition of the materials inside the reactor which is a function of residence time and rate of reaction that had been considered in this experiment. CSTR that used in the experiment, (model: BP 143) is designed for student’s experiments on chemical reaction in liquid phase which is under adiabatic and isothermal conditions. CSTR consists of two tanks of solutions and one reactor. The model also consists of jacketed reaction fitted in the agitated and condenser. The unit comes complete with vessels for raw materials and products, feed pumps and thermostat that set at 500C.

The reactor is modelled in order to perform the

saponification reaction where the reaction is occur between the sodium hydroxide,NaOH and ethyl acetate, Ac. The saponification process between this compounds produced sodium acetate in a batch and the continuous stirred tank reactor evaluate the rate data needed to design a production scale reactor.

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] OBJECTIVES: 1. To verify the conductivity values by manual determination on experimental samples. 2. To carry out saponification reaction between NaOH and Et(Ac) in CSTR. 3.

To determine the effect of residence time onto the reaction extent of conversion.

4. To determine the reaction rate constant.

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] THEORY: Rate of equation and rate law The rate of reactions or speed of reaction for a reactant and products in particular reactions can be defined as how fast or slow the reaction takes place. For examples is about he oxidation process between iron under the atmospheric is undergoes a slow reaction compare to the combustion of butane in a fire that can be categories as fast reaction. Consider the chemical reaction as below: aA + bB

 pP + qQ

………………..(eq 1)

The lowercase letter which are a,b,p,and q refer to the stoichiometric coefficient while the capital letter which are A,B,P and Q refer to the reactants and products. According to the IUPAC’s Gold Book definition the rate of reaction, r in the chemical reaction is occur in a closed system which is under a constant –volume conditions, whitout build up of reaction intermediates, is defines as:

Where [A], [B], [P] and [Q] are referred to the molarity of the substances. Based on IUPAC the times must be in second and the rate of reaction is in a positive sign. The mass balance for any system in general is: IN - OUT + GENERATION -CONSUMPTION= ACCUMULATION Mass is a conservative entity, hence given a control volume V the sum of mass flows entering the system will be equal to the sum exiting minus (plus) the consumed (generated) or accumulated fractions.

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] Continuous Stirred Tank Reactors (CSTR)

CSTR runs at steady state with continuous flow of reactants and products; the feed assumes a uniform composition throughout the reactor, exit stream has the same composition as in the tank.

General Mole Balance Equation

Assumptions Steady state, therefore dNA/dt = 0

Well-mixed therefore is the same throughout the reactor. Rearranging the generation, V = (FAo – FA)/ -rA In terms of conversion,

X = (FAo – FA) / FAo V = (FAoX) / -rA

A calibration curve is a method used in analytical chemistry to determine the concentration of an unknown sample solution. It is a graph generated by experimental means, with the concentration of

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] solution plotted on the x-axis and the observable variable — for example, the solution’s absorbance — plotted on the y-axis. The curve is constructed by measuring the concentration and absorbance of several prepared solutions, called calibration standards. Once the curve has been plotted, the concentration of the unknown solution can be determined by placing it on the curve based on its absorbance or other observable variable.

Residence Time The reactor’s residence time is defined as the reactor volume divided by the total feed flow rates. Residence time, τ =

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] PROCEDURES: General start-up Procedures: 1. The following solution were prepared: i-

40L of sodium hydroxide, NaOH (0.1 M)

ii-

40 L of ethyl acetate, Et (Ac) (0.1M)

iii-

1 L of hydrochloric acid, HCl (0.25M) , for quenching.

2. All valves were initially closed. 3. The feed vessels were charged as follows: i-

The charge port caps for vessels B1 and B2 were opened.

ii-

The NaOH solution was carefully poured into vessel B1 and Et (Ac) solution was poured into vessel B2.

iii-

The charge port caps for both vessels were closed.

4. The power for control panel was turned on. 5. Sufficient water in thermostat T1 was checked. Refill as necessary. 6. The overflow tube was adjusted to give a working volume of 10L in the reactor R1. 7.

Valves V2, V3, V3, V7, V8 and V11 were opened.

8. The unit was ready for experiment. General shut-down Procedures: 1. The cooling water valve V13 was kept open to allow the cooling water to continue flowing. 2. Pumps P1 and pumps P2 were switched off. Stirrer M1 was switched off. 3. The thermostat T1 was switched off. The liquid in the reaction vessel R1 was let to cool down to room temperature. 4. Cooling water V13 was closed. 5. Valves V2, V3, V7, and V8 were closed. Valves V4, V9 and V12 were opened to drain any liquid from the unit. 6. The power for control panel was turned off.

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] Preparation of Calibration Curve for Conversion vs Conductivity: 1. The following solution were prepared: i-

1 L of sodium hydroxide, NaOH (0.1M)

ii-

1 L of sodium acetate , Et (Ac) (0.1M)

iii-

1 L of deionised water, H2O.

2. The conductivity and NaoH concentration for each valu were determined by mixing the following solution into 100 mL of deionised water. i-

0% conversion

: 100 mL NaOH

ii-

25% cinversion

: 75 mL NaOH + 25 mL Et (Ac)

iii-

50% conversion

: 50 mL NaOH + 50 mL Et (Ac)

iv-

75% conversion

: 23 mL NaOH + 75 mL Et (Ac)

v-

100% conversion

: 100 mL Et (Ac)

Back Titration Procedures for Manual Conversion Determination: 1. A burette was filled up with 0.1 M NaOH solution. 2. 10 mL of 0.25 M HCl was measured in a flask. 3. A 50 mL sample was obtained from the experiment and immediate the sample was added to the HCl in the flask to quench the saponification reaction. 4. A few drops of pH indicator were added into the mixture. 5. The mixture was titrated with NaOH solution from the burette until the mixture was neutralized. The amount of NaOH titrated was recorded. Effect of Residence Time of The Reaction in a CSTR: 1. The general start-up procedures was performed. 2. Pump 1 and pump 2 were switched on and valves V5 and V10 were opened to obtain the highest possible flow rate into the reactor. 3. The reactor was filled up with both of the solution until it is njust bout to overflow. 4. Valves V5 and V10 were readjusted to give a flow rate of about 0.1 L/min. the flow rate for both valves must be same. The flow rate were recorded into a data. 5. The stirrer M1 was switched on and the speed was set about 200 rpm. 6. The conductivity value at Q1 was started monitoring until id does not change over time. This is to ensure that the reactor has reached steady state. 7. The steady state conductivity value was recorded and the concentration of NaOH and extent of conversion in the reactor was found out from the calibration curve.

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] 8. Sampling valve V12 was opened and 100mL of sample was collected. It directly proceed with the back titration procedures to manually determine the concentration of NaOH in the reactor and extent of conversion. 9. The experiments was repeated (steps 5-9) for different residence times by adjusting the feed flow rate of NaOH and Et(Ac) to about 0.15, 0.20, 0.25, and 0.30 L/min. the flow rate for both must be same.

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] APPARATUS: 1. Continuous stirred tank reactor. Model: BP 143 2. 50 mL burette 3. 200 mL beaker 4. Conical flask 5. Solution : I-

Sodium hydroxide, NaOH (0.1M)

II-

Ethyl acetate, Et (Ac) (0.1M)

III-

Deionised water

IV-

Phenolphthalein

6. Conductivity probe 7. 100 mL measuring cylinder.

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] RESULTS: Preparation of calibration curves:

Solution Mixtures Conversion

Concentration Conductivity

0.1 M NaOH

0.1 M Et (Ac)

H2O

of NaOH (M)

(mS/cm)

0%

100 mL

-

100 mL

0.0500

6.56

25 %

75 mL

25 mL

100 mL

0.0375

4.05

50 %

50 mL

50 mL

100 mL

0.0250

2.11

75 %

25 mL

75 mL

100 mL

0.0125

8.67

100 %

-

100 mL

100 mL

0.0000

19.00

Conductivity versus Conversion 20 18

CONDUCTIVITY (mS/cm)

16 14 12 10 8

Conductivity (mS/cm)

6 4 2 0 0%

20%

40%

60%

80%

100%

120%

CONVERSIONS (%)

Graph 1: conductivity versus conversion

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] Back titration for manual conversion determination:

Sample

Vol. Of NaOH (mL)

1

22.0

2

22.4

3

22.3

4

22.0

5

21.9

Tables of experiment 1: Reactor volume = 10 L Concentration of NaOH in feed vessel = 0.1 M Concentration of Et(Ac) in feed vessel = 0.1 M No.

Flow rate

Flow rate of

Residence

Conductivit

Exit

Conversion, X

Of NaOH

Et(Ac)

time, τ (min)

y (mS/cm)

concentration

(%)

(mL/min)

(mL/min)

of NaOH, CNaOH (M)

1 0.10

0.10

50.00

3.08

0.006

98.80

2

0.15

0.15

33.33

3.01

0.0052

89.60

3

0.20

0.20

25.00

2.95

0.0054

89.20

4

0.25

0.25

20.00

2.93

0.0060

88.00

5

0.30

0.30

16.67

2.94

0.0062

87.60

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title]

Residence time, τ versus convension 60

Residence time (min)

50 40 30 Residence time, τ (min) 20 10 0 86

88

90

92

94

96

98

100

conversion (%)

Graph 2: residence time versus convension.

SAMPLE CALCULATION: 1) F0 = 0.1+0.1 = 0.2 L/min Known quantities: Volume of sample, Vs = 50 mL Concentration of NaOH in the feed vessel, CNaOH,f = 0.1 mol/L Volume of HCL for quenching, VHCl,s = 10 mL Concentration of HCl in standard solution, CHCls = 0.25 mol/L Volume of titrated NaOH, V1= 9.8 mL Concentration of NaOH used for titration, CNaOHs = 0.1 mol/L

i-

Concentration of NaOH that entering the reactor, CNaOH0.

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] CNaOHo = ½ CNaOHf = ½ (0.1) = 0.05 mol/L

ii-

Volume of unreacted quenching HCl,V2 V2 = (CNaOHs / CHCls) x V1 = (0.1/0.25) x 22 = 8.8 mL

iii-

Volume of HCl reacted with NaOHin sample, V3 V3 = VHCls – V2 = 10 – 8.8 = 1.20

iv-

Moles of HCl reacted with NaOH in sample, n1 n1 = (CHCls x V3) / 1000 = 0.25 x 1.2/1000 = 0.0003 mol

v-

Moles of unreacted NaOH in sample, n2 n2 = n1 = 0.0003 mol

vi-

Concentration of unreacted NaOH in the reactor, CNaOH CNaOH = n2/Vs x 1000 = 0.0003/50 x 1000 = 0.006 mol/L

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] vii-

Conversion of NaOH in the reactor, X

X = (1- CNaOH / CNaOHo) x 100% = (1 – 0.006/0.05) x 100% = 98.8 %

viii-

Residence time, τ τ = VCSTR / Fo = 10 / 0.20 = 50 min

ix-

Reaction rate constant, k k = ( CAo – CA) / τCA2 = ( 0.05 – 0.006) / (50 x 0.0062) = 24.44 M-1 min -1

x-

Rate of reaction, -rA -rA = kCA2 = 24.44 x 0.0062 = 8.79 x 10 -4 mol/L.min

2) F0 = 0.15 + 0.15 = 0.3 L/min Known quantities: Volume of sample, Vs = 50 mL Concentration of NaOH in the feed vessel, CNaOH,f = 0.1 mol/L Volume of HCL for quenching, VHCl,s = 10 mL Concentration of HCl in standard solution, CHCls = 0.25 mol/L

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] Volume of titrated NaOH, V1= 22.4 mL Concentration of NaOH used for titration, CNaOHs = 0.1 mol/L i-

Concentration of NaOH that entering the reactor, CNaOH0.

CNaOHo = ½ CNaOHf = ½ (0.1) = 0.05 mol/L

ii-

Volume of unreacted quenching HCl,V2 V2 = (CNaOHs / CHCls) x V1 = (0.1/0.25) x 22.4 = 8.96 mL

iii-

Volume of HCl reacted with NaOHin sample, V3 V3 = VHCls – V2 = 10 – 8.96 = 1.04

iv-

Moles of HCl reacted with NaOH in sample, n1 n1 = (CHCls x V3) / 1000 = 0.25 x 1.04/1000 = 0.00026 mol

v-

Moles of unreacted NaOH in sample, n2 n2 = n1 = 0.00026 mol

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] vi-

Concentration of unreacted NaOH in the reactor, CNaOH CNaOH = n2/Vs x 1000 = 0.00026/50 x 1000 = 0.0052 mol/L

vii-

Conversion of NaOH in the reactor, X

X = (1- CNaOH / CNaOHo) x 100% = (1 – 0.0052/0.05) x 100% = 89.6 %

viii-

Residence time, τ τ = VCSTR / Fo = 10 / 0.30 = 33.33 min

ix-

Reaction rate constant, k k = ( CAo – CA) / τCA2 = ( 0.05 – 0.0052) / (33.33 x 0.00522) = 49.709 M-1 min -1

x-

Rate of reaction, -rA -rA = kCA2 = 49.709 x 0.00522 = 1.344 x 10 -3 mol/L.min

3) F0 = 0.20 + 0.20 = 0.4 L/min Known quantities: Volume of sample, Vs = 50 mL Concentration of NaOH in the feed vessel, CNaOH,f = 0.1 mol/L

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] Volume of HCL for quenching, VHCl,s = 10 mL Concentration of HCl in standard solution, CHCls = 0.25 mol/L Volume of titrated NaOH, V1= 22.3 mL Concentration of NaOH used for titration, CNaOHs = 0.1 mol/L i-

Concentration of NaOH that entering the reactor, CNaOH0.

CNaOHo = ½ CNaOHf = ½ (0.1) = 0.05 mol/L

ii-

Volume of unreacted quenching HCl,V2 V2 = (CNaOHs / CHCls) x V1 = (0.1/0.25) x 22.3 = 8.92 mL

iii-

Volume of HCl reacted with NaOHin sample, V3 V3 = VHCls – V2 = 10 – 8.92 = 1.08

iv-

Moles of HCl reacted with NaOH in sample, n1 n1 = (CHCls x V3) / 1000 = 0.25 x 1.08/1000 = 0.00027 mol

v-

Moles of unreacted NaOH in sample, n2 n2 = n1 = 0.00027 mol

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title]

vi-

Concentration of unreacted NaOH in the reactor, CNaOH CNaOH = n2/Vs x 1000 = 0.00027/50 x 1000 = 0.0054 mol/L

vii-

Conversion of NaOH in the reactor, X

X = (1- CNaOH / CNaOHo) x 100% = (1 – 0.0054/0.05) x 100% = 89.2 %

viii-

Residence time, τ τ = VCSTR / Fo = 10 / 0.40 = 25.0 min

ix-

Reaction rate constant, k k = ( CAo – CA) / τCA2 = ( 0.05 – 0.0054) / (25 x 0.00542) = 61.17 M-1 min -1

x-

Rate of reaction, -rA -rA = kCA2 = 61.17 x 0.00522 = 1.654 x 10 -3 mol/L.min

4) F0 = 0.25 + 0.25 = 0.5 L/min

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] Known quantities: Volume of sample, Vs = 50 mL Concentration of NaOH in the feed vessel, CNaOH,f = 0.1 mol/L Volume of HCL for quenching, VHCl,s = 10 mL Concentration of HCl in standard solution, CHCls = 0.25 mol/L Volume of titrated NaOH, V1= 22.0 mL Concentration of NaOH used for titration, CNaOHs = 0.1 mol/L i-

Concentration of NaOH that entering the reactor, CNaOH0.

CNaOHo = ½ CNaOHf = ½ (0.1) = 0.05 mol/L

ii-

Volume of unreacted quenching HCl,V2 V2 = (CNaOHs / CHCls) x V1 = (0.1/0.25) x 22.0 = 8.80 mL

iii-

Volume of HCl reacted with NaOHin sample, V3 V3 = VHCls – V2 = 10 – 8.80 = 1.20

iv-

Moles of HCl reacted with NaOH in sample, n1 n1 = (CHCls x V3) / 1000 = 0.25 x 1.20/1000 = 0.00030 mol

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title]

v-

Moles of unreacted NaOH in sample, n2 n2 = n1 = 0.00030 mol

vi-

Concentration of unreacted NaOH in the reactor, CNaOH CNaOH = n2/Vs x 1000 = 0.00030/50 x 1000 = 0.006 mol/L

vii-

Conversion of NaOH in the reactor, X

X = (1- CNaOH / CNaOHo) x 100% = (1 – 0.006/0.05) x 100% = 88.0 %

viii-

Residence time, τ τ = VCSTR / Fo = 10 / 0.50 = 20.0 min

ix-

Reaction rate constant, k k = ( CAo – CA) / τCA2 = ( 0.05 – 0.006) / (20 x 0.0062) = 61.11 M-1 min -1

x-

Rate of reaction, -rA -rA = kCA2 = 61.11 x 0.0062 = 2.20 x 10 -3 mol/L.min

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] 5) F0 = 0.30 + 0.30 = 0.6 L/min Known quantities: Volume of sample, Vs = 50 mL Concentration of NaOH in the feed vessel, CNaOH,f = 0.1 mol/L Volume of HCL for quenching, VHCl,s = 10 mL Concentration of HCl in standard solution, CHCls = 0.25 mol/L Volume of titrated NaOH, V1= 21.9 mL Concentration of NaOH used for titration, CNaOHs = 0.1 mol/L i-

Concentration of NaOH that entering the reactor, CNaOH0.

CNaOHo = ½ CNaOHf = ½ (0.1) = 0.05 mol/L

ii-

Volume of unreacted quenching HCl,V2 V2 = (CNaOHs / CHCls) x V1 = (0.1/0.25) x 21.9 = 8.76 mL

iii-

Volume of HCl reacted with NaOHin sample, V3 V3 = VHCls – V2 = 10 – 8.76 = 1.24

iv-

Moles of HCl reacted with NaOH in sample, n1 n1 = (CHCls x V3) / 1000 = 0.25 x 1.24/1000 22

CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] = 0.00031 mol

v-

Moles of unreacted NaOH in sample, n2 n2 = n1 = 0.00031 mol

vi-

Concentration of unreacted NaOH in the reactor, CNaOH CNaOH = n2/Vs x 1000 = 0.00031/50 x 1000 = 0.0062 mol/L

vii-

Conversion of NaOH in the reactor, X

X = (1- CNaOH / CNaOHo) x 100% = (1 – 0.0062/0.05) x 100% = 87.6 %

viii-

Residence time, τ τ = VCSTR / Fo = 10 / 0.60 = 16.67 min

ix-

Reaction rate constant, k k = ( CAo – CA) / τCA2 = ( 0.05 – 0.0062) / (16.67 x 0.00622) = 68.352 M-1 min -1

x-

Rate of reaction, -rA -rA = kCA2 = 68.352 x 0.00622 = 2.627 x 10 -3 mol/L.min

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] DISCUSSION: According to the experiment that had been conducted, we need to achieve three objectives which are to carry out the saponification process between NaOH and Et (Ac) in a CSTR reactor, to determine the effect of the residence time onto the reaction extent of conversion and lastly to determine the constant rate of reaction. From the data collected, two graph had been plotted which are conductivity versus conversion and residence time versus conversion. From the graph 1, we can conclude that the conductivity is not consistent which are the line slow down at 50% conversion which is the conductivity is 2.11 but then it increase until 100% conversion. While for the second graph which is residence time versus conversion. For this graph we can see that the residence time is increase proportionally to the conversion. It can be conclude that that residence is higher if the conversion is higher. But there are certain fluctuate peak which due to the error that may be affects the result and graph. For the saponification process, it is one kind of process to make a soap. Saponification process is a continuous reaction. In this experiment, the reaction of saponification is quenching with hydrochloric acid to stop the reaction. The reaction rapidly reacts in increasing of experiment. Back titration is done to investigate if the reaction is stop. As the result for rates of constant is not correspond to the theory, thus there are some errors occurred during this experiment such as while taking the reading of the burette the position of the eyes is not at the same level of the meniscus. So, to improve the reading and get the better results, the positions of the eyes must be parallel to the meniscus. Besides, we have to rinse all the apparatus before we use it. This is to ensure that all the beakers, or burette is clean so that any chemical that we put into these apparatus does not react with any others chemicals.by doing all these precaution, we can get more accurate reading and thus improve the results.

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] CONCLUSION: Based on the objectives of this experiment, which is to determine the residence time onto the reaction extent of conversion, the relationship conversion and residence time was directly proportional. But the reaction rates constant were determined for all varies flow rate. From the calculated data, the rate constant of reaction is increasing when the conversion is higher. We can conclude that the experiment was successfully conducted since we get the right conclusion.

RECOMMENDATIONS: 1. Make sure reactor does not have any leaks and valve closed and opened as needed, controlled the valve carefully and slowly when adjusting the flow rate to obtain 0.10 L/min. It is to make sure flow rate will stabilize and the experiment will run smoothly. 2. Repeat titrations two or three times because a lot of error comes from titration or use another method other than titration. 3. Divide into two teams which is the first team in charge of the CSTR 40 liters machine while the second team would carry out the back titration procedures. 4. Take conductivity reading when the conductivity not changes in time because it can change rapidly in short of time. 5. Make sure CSTR 40 liters machine is running appropriately, it to prevent harm to the machine and individual that used the machine.

REFERENCES: 1. http://www.metal.ntua.gr/~pkousi/e-learning/bioreactors/page_06.htm 2. http://www.wisegeek.com/what-is-a-calibration-curve.htm

3. http://www.engin.umich.edu/~cre/asyLearn/bits/cstr/index.htm

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title] APPENDICES:

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CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title]

27

CONTINUOUS STIRRED TANK REACTOR (CSTR) 40 LITRES 2013 [Type the document title]

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