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NATIONAL INSTITUTE OF TECHNOLOGY, TIRUCHIRAPPALLI – 15

DEPARTMENT OF CHEMICAL ENGINEERING

CHEMICAL REACTION ENGINEERING LABORATORY MANUAL

Department of Chemical Engineering 1

Experiments Order

1) Adiabatic Reactor

2) Batch Reactor –I

3) Batch Reactor –II

4) Mixed Flow Reactor

5) Mixed Flow Reactor in Series

6) Plug Flow Reactor

7) Mixed Flow Reactor followed by Plug Flow Reactor

8) RTD Studies in a Plug Flow Reactor

9) RTD studies in a Mixed Flow Reactor


ADIABATIC REACTOR

Aim:

To study the effect of temperature on the rate of reaction between hydrogen peroxide

and sodium thiosulphate under adiabatic reaction conditions and to determine the activation

energy of the reaction.

Theory:

The effect of temperature on the reaction mixture consisting of hydrogen peroxide and

sodium thiosulphate when the reaction is carried out under adiabatic conditions, it can be

observed and correlation with the reaction rate is given. As the exothermic reaction proceeds,

the temperature increases and becomes constant. The rate of the reaction and temperature are

correlated to various temperatures.

Where

TF – Final Temperature (°C)

T0 – Initial Temperature (°C)

K – Rate constant

CA0 – Initial concentration (moles/ litre)

A graph is drawn between lnA Vs.1/T and the slope is equated to -E/R.

Procedure:

Take 30 ml of hydrogen peroxide in a beaker and dilute it into 300 ml by using distilled

water and pour it into the reactor, 300 ml of sodium thiosulphate solution will also be added

in the reactor. Due to exothermic reaction, the temperature of reaction mixture starts

increasing, the rise in temperature is noted at different time intervals as the reaction proceeds.

Tabulation:

Time (sec) Temperature

(°C)

dT/dt (Ts – T)2 1/(T+273)

(k-1)

A ln A

0F

RTEA0

2f TT

KC

dt

dT

TT

1 e


Model Graph:

Model Calculation:

1) t =

2) T =

3) dt

dT

4) (Tf – T)2=

5) 2

f

3

T)(T

10

dt

dTA

=

6) lnA =

7) 273)(T

1

=

8) E= -slope x R=

Result and Inferences:

--------------

Slope = -E/R

1/T (k-1) x 0 ln

A

T°C

Time (s)


BATCH REACTOR -1

Aim:

To verify the order and to determine the rate constants for the reaction between

equimolar quantity of NaOH and ethyl acetate in a batch reactor.

Reaction:

NaOH + CH3COOC2H5 CH3COONa + C2H5OH

Theory:

For a second order reaction, the rate of reaction is as follows

2A

AKC

dt

dC

Integrating,

A

A

A

C

CA

C

CAA

A

x1

x

KC

1t

C1

K

1

KC

dCt

0

A

A0

A

0

2

Procedure:

500 ml of NaOH and 500 ml of ethyl acetate are taken in the batch reactor with the

starting and stop water. Then each 10 ml of the reaction mixture is taken every 5 minutes the

reaction is arrested by adding acetic acid to the sample. The reaction mixture is titrated

against sodium hydroxide of known normality and its concentration found. Samples are taken

up to 50 minutes and the concentration of the reactor is found.

Standard Data:

Normality of NaOH=

Normality of CH3COOC2H5=

Normality of CH3COOH=

Tabulation:

S.No. Reaction

Time (min)

Volume of

NaOH (ml)

Naormality

of NaOH (N)

CA

(mol/lit)×10 -3

1/CA

(lit/mol)

XA

A

A

X1

X

1 5

2 10

3 15

4 20

5 25

6 30

7 35

8 40

9 45

10 50


Model Graph:

Model Calculation:

1) 2

NC

NaOHA0 =

2) VolumeSample

addedNaOHofmolesaddedCOOHCHofmolesC

3A

=

3) AC

1=

4) 0

0

A

AAA

C

CCX

=

5) A

A

X1

X

Result:

Thus the experiment on batch reactor was performed. The value of K found from

graph.

1/CA vs t =

XA /(1-XA) vs t =

----------

t

k AC1

0AC1

0 x

t x

0

kCA0

y y

A

A

X-1

X


BATCH REACTOR – II

Aim:

To verify the order and to determine the rate constants for the reaction between non-

equimolar quantity of NaOH and ethyl acetate in a batch reactor.

Reaction:

NaOH + CH3COOC2H5 CH3COONa + C2H5OH

Theory:

In a batch reactor, the composition of the components is uniform throughout at any

instant of time

A

A

AB

BA A

0A

AA

X1m

Xmln

)C-K(C

1

CKCr-

ProductsB)(Afor

)(-r

kXCt

00

XA

0

Procedure:

400 ml of NaOH and 800 ml of ethyl acetate of known concentration are taken in the

reactor. Samples (10ml) are drawn for every 5 minutes from the reactor up to 50 minutes. The

concentration of reactants in the sample is found out by adding 10 ml of acetic acid and

titrating against sodium hydroxide.

Standard Data:

Normality of NaOH=



Tabulation:

S.No. Reaction

Time (min)

Volume of

NaOH (ml)

Naormality

of NaOH (N)

CA

(mol/lit)×10 -3

CBo

(mol/lit)

XA

)Xm(1

Xmln

A

A

1 5

2 10

3 15

4 20

5 25

6 30

7 35

8 40

9 45

10 50

Model Graph:


Model Calculation:

1) total

NaOHNaOHA

V

NVC 0

=

2)

VolumeTotal

VNVNC

NaOHA.AA

=

3) total

EAEAB

V

NVC 0

=

4) 0

0

A

B

C

CM =

5) 0

0

A

AAA

C

CCX

=

6) 00 AB CC

SlopeK

=

Result:

Thus the experiment on batch reactor – II was performed. The value of k found the

graph is

------------

Time (min) x

0

Slope = K (CB0 – CA0)

y

A

A

X1m

Xmln


MIXED FLOW REACTOR

Aim: To study the performance of a mixed flow reactor using second order saponification

reaction.

Reaction:

NaOH + CH3COOC2H5 → CH3COONa + C2H5OH

Theory:

In a mixed flow reactor, properties of the reaction mixture are uniform. Thus for

example, concentration of the reactants at inlet of the second order reaction and outlet

concentration of the reactants remain the same. The design equation for reaction

CA0 = CB0, CA = CB, 2

A

AA

KC

CC 0

Experimental Setup:

It consists of a 500ml flask with a flow steam. This is attached with the flow meter for

setting the flow rate.

Procedure: The residence time of the reactor is adjusted by adjusting of reactants the flow rate

and keeping the reactor volume constant. When steady state is reached a sample is collected.

Excess acetic acid is added to the sample in order to arrest the reaction. Thus moles of

unreacted reactants and hence the conversion can be found.

Standard Data:

Normality of NaOH=



Flow rate of NaOH

Flow rate of CH3COOC2H5=

Reaction Rate Constant =

Table: 1

S.No. Volume of Sample

(ml)

Burette Reading (ml) Concordant Value (ml)

Initial Final

Model Calculation:

1)

V

=

2)

total

NaOHCOOHCHA

V

NVNVC

3

3) 0

0

A

AAAexp

C

CCX

4) 2AAAtheo X1kTCX 0

Result: Thus the experiment of mixed flow reactor is studied and the conversion is found to be:

XATheo:

XAExp:

---------------


MIXED FLOW REACTOR IN SERIES

Aim: To study the performance of a mixed flow reactor in series, using second order

saponification.

Reaction:


− rA = KCACB = KCA2

Theory:

In a mixed flow reactor, properties of the reaction mixture are uniform. Thus we have

the equimolar concentration of reactant at inlet for the second order reaction. The outlet

concentration will hence be the same.

CA0 = CB0, CA = CB,

2A1

AA1

KC

CC 0τ

2A2

A2A12

KC

CCτ

2AA0

A

X-1KC

Xτ

Procedure: The residence time of the reactor is adjusted by setting the flow rate of reactants and

keeping the reactor volume constant. When steady state is reached a sample is collected and

excess acetic acid is used to arrest the reaction. Thus moles of unreacted reactants and the

conversion can be found.

Standard Data:

Normality of NaOH=



Flow rate of NaOH



Table: 1

S.No. Volume of Sample Burette Reading (ml) Concordant Value (ml)

Initial Final

Table: 2

S.No. Volume of Sample Burette Reading (ml) Concordant Value (ml)

Initial Final


Model Calculation:

NaOH

COOHCHCOOHCHNaOH

V

NVN

33

At steady state in Reactor I

Volume

NVNVC

NaOHCOOHCHA

3

1

0

10

1

A

AAA

C

CCX

At steady state in Reactor II

Volume

NVNVC

NaOHCOOHCHA

3

2

0

20

2

A

AAA

C

CCX

Theoretical conversion:

Reactor I:

11

Vτ

21

AA0

A1

X-1KC

Xτ

Reactor II:

22

Vτ

212

AA0

AA2

X-1KC

X-Xτ

Result: Thus the experiment of mixed flow reactor in series is studied and the conversion is

found to be:

Reactor 1

XA,Theo :

XA,Exp :

Reactor 2

XA,Theo :

XA,Exp :

---------


PLUG FLOW REACTOR

Aim:

To study the performance of the plug flow reactor for the second order reaction of

saponification of ethyl acetate.

Reaction:


0A

0A

A

A

A

A

C

CA

C

CAA

A

CK1

CKX

x1

x

KC

1t

C1

K

1

KC

dCt

0

A

A0

A

0

2

Experimental setup:

It consists of a transparent tube provided with glass beads ( = 0.04) sampling can be

done at different points all along the length of the tube.

Procedure:

NaOH and CH3COOC2H5 solution of equal flow rate is allowed to enter at a constant

flow rate until steady state is reached. When the inlet flow rate equals the outlet flow rate, the

steady state is said to be attained. Samples are collected at different position, acetic acid is

added to arrest the reaction. The concentration of unreacted NaOH and conversion in the

mixture is noted.

Standard Data:

Normality of NaOH=



Flow rate of NaOH



Tabulation:

S.No Reactor volume

(ml)

Space time

(min)

Titrant

volume (ml)

CA (N)

×10 – 3

XA (%)

(expt.)

XA (%)

(theo)

Model Graph:


Model Calculation:

1) Initial Concentration= NNaOH/2

2) 0V

Vτ

3)

Volume

NVNVC

NaOHCOOHCHA

3

4) 0A

AAexp

C

C1X

5) 0

0

A

AAtheo

KC1

KCX

ττ

Result: Thus the performance of plug flow reactor under constant flow rate is studied and

necessary graphs are drawn.

-----------

Theoretical

Experimental

XA

x 0

y

Time


MIXED FLOW FOLLOWED BY PLUG FLOW REACTOR

Aim: To study the performance of a mixed flow followed by plug flow reactor using second

order saponification reaction.

Reaction:


Theory:

In a mixed flow reactor, properties of the reaction mixture are uniform. Thus for

example, concentration of the reactants at inlet of the second order reaction and outlet

concentration of the reactants remain the same. The design equation for reaction

CA0 = CB0, CA = CB, V

V11τ

2A1

A1A1

KC

CC 0τ

Whereas in plug flow the concentration of the reactants are changing along with length and

hence the with residence time as volume of the reactor changing with the length for give a

flow rates of reactants

V

V22τ ;

0

0

A2

2AAtheo

KC1

KCX

ττ

Experimental Setup:

It consists of a 1000ml flask attached with stirrer and transparent tube provided with

glass beads ( = 0.04) sampling can be done at different points all along the length of the

tube.

Procedure: The residence time of the reactor is adjusted by adjusting of reactants the flow rate

and keeping the reactor volume constant. When steady state is reached a sample is collected

and excess acetic acid is used to arrest the reaction. Thus moles of unreacted reactants and the

conversion can be found.

Standard Data:

Normality of NaOH=



Flow rate of NaOH



S.No Reactor volume

(ml)

Space time

(min)

Titrant

volume (ml)

CA (N)

×10 – 3

XA (%)

(expt.)

XA (%)

(theo)

Model Calculation:

NaOH

COOHCHCOOHCHNaOH

V

NVN

33


At steady state in Reactor I

Volume

NVNVC

NaOHCOOHCHA

3

1

0

10

1

A

AAA

C

CCX

At steady state in Reactor II

Volume

NVNVC

NaOHCOOHCHA

3

2

0

20

2

A

AAA

C

CCX

Theoretical conversion:

Reactor I:

V

V11τ

21

AA0

A1

X-1KC

Xτ

Reactor II:

V

V22τ

4) 0

0

A2

2AAtheo

KC1

KCX

ττ

Result: Thus the performance of mixed flow followed by plug flow reactor under constant flow

rate is studied and necessary graphs are drawn.

----------

Theoretical

Experimental

XA

x 0

y

Time


RTD STUDIES IN A PLUG FLOW REACTOR

Aim:

To study the behavior of a plug flow reactor by RTD studies.

Theory:

Elements of fluid taking different routes through the reactor may take different lengths

of time to pass through the vessel. The distribution of these times for the stream of fluid

leaving the vessel is called the exit age distribution E, or the residence time distribution

(RTD) of the fluid. From E mean residence time, flow pattern, model parameters can be

evaluated.

Procedure:

In a plug flow reactor, a tube packed with particles is used. To start with reactor is

filled with 0.05N of NaOH Water flow is allowed from a water tank above the reactor. The

variation of concentration of sodium hydroxide in the each taping point is noted. The

dispersion number is obtained from the graph.

Standard Data:

Normality of CH3COOH =

Flow rate of Water =

Normality of NaOH (Nmax) =

Formulae:

1) ΔtiEtt ii

2) 2

ii2

i2 tΔtEtσ

3) 2

2

0

t

σσ 2

4) 2

σ

UL

D 20

5) N

1σ 2

0

where,

timeresidencemeant

varianceσ2

∆ti = time interval

numberDispersionUL

D

Tabulation:

Time

(min)

VCH3COOH

(ml)

NNaOH

max

NaOH

N

NF

dt

dFEi

Eiti Eiti2


Model Graph:

Model Calculation:

1) 1 NNaOH =

2) maxN

NF

3) F = y (t)

4) dt

dFE

5) ΔtiEtt ii

6) 2

ii2

i2 tΔtEtσ

7) 2

2

0

t

σσ 2

8) 2

σ

UL

D 20

9) N

1σ 2

0

Result:

Thus, the experiment of plug flow RTD was conducted and the dispersion number and

N were calculated.

F E

y y

x x t t


RTD STUDIES IN MIXED FLOW REACTOR

Aim: To study the behavior of the mixed flow reactor through RTD studies.

Theory:

Elements of fluid taking different routes through the reactor may take different lengths

of time to pass through the vessel. The distribution of these times for the stream of fluid

leaving the vessel is called the exit age distribution E, or the residence time distribution

(RTD) of the fluid. From E mean residence time, flow pattern, model parameters can be

evaluated.

Experimental setup and procedure: Reactor consists of 500 ml beaker attached with stirrer. The flow of water is allowed

from a bottle packed above the level of the reactor. The concentration of NaOH in the exit

stream is determined in the samples collected at intervals the graphs are hence obtained.

Standard Data:

Normality of CH3COOH =

Flow rate of Water =

Normality of NaOH (Nmax) =

Formulae:

1) ΔtiEtt ii

2) 2

ii2

i2 tΔtEtσ

3) 2

2

0

t

σσ 2

4) 2

σ

UL

D 20

5) N

1σ 2

0

where,

timeresidencemeant

varianceσ2

∆ti = time interval

numberDispersionUL

D

Tabulation:

Time

(min)

VCH3COOH

(ml)

NNaOH

max

NaOH

N

NF

dt

dFEi

Eiti Eiti2


Model Graph:

Model Calculation:

1) maxN

NF

2) F = y (t)

3) dt

dFE

4) ΔtiEtt ii

5) 2

ii2

i2 tΔtEtσ

6) 2

2

0

t

σσ 2

7) 2

σ

UL

D 20

8) N

1σ 2

0

Result:

Thus, the experiment of mixed flow RTD was conducted and the dispersion number

and N were calculated.

--------------

F C

y y

x x t t

x’ x’

y’ y’

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