93598856-cre-lab-manuals.pdf

7/30/2019 93598856-Cre-Lab-Manuals.pdf

1/18

NATIONAL INSTITUTE OF TECHNOLOGY, TIRUCHIRAPPALLI 15

DEPARTMENT OF CHEMICAL ENGINEERING

CHEMICAL REACTION ENGINEERING LABORATORY MANUAL


2/18

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 inthe 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

Department of Chemical Engineering 2

( ) 0F

RTEA0

2

f TT

KC

dt

dT

TT

1 e

=


3/18

Model Graph:

Model Calculation:

1) t =2) T =

3) =dt

dT

4) (Tf T)2

5) 2f T)(T

1

dt

dTA

=

6) lnA =

7)273)(T

1

+=

8) Slope= -E/R9) E=

Result and Inferences:

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

Department of Chemical Engineering

Slope = -E/R

1/T (k-1) x0

lnA

TC

Time (s)

3


4/18

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:

50 ml of NaOH and 50 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 Acitic Acid:

Normality of Ethyl acetate:

Tabulation:

S.No. Reaction

Time (min)

Volume of

CH3COOH(ml)

Volume of

NaOH (ml)

CA(mol/lit)

1/CA(lit/mol)

XA

A

A

X1

X

1 5

2 10

3 154 20

5 25

6 30

7 35

8 40

9 45

10 50



5/18

Model Graph:

Model Calculation:

1)2

NC

NaOH

0A=

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 order of the reaction was

verified and the value ofKfound from graph.

K=-----------------------(1/CA vs time graph)

K=----------------------- (XA/(1-XA) vs time graph)

**********

BATCH REACTOR II


t

kAC1

0AC1

0

x

t

x

0

kCA0

yy

A

A

X-1

X

5


6/18

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:


Theory:

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

instant of time

( )

( )

=

+

=

=

A

A

A0B0

BAA

0A

AA

X1M

XM

ln)C-KC

1

CKCr-

ProductsB)(Afor

)(-r

kXCt

XA

0

Procedure:

200 ml of NaOH and 400 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 :

Normality of Acitic Acid:Normality of Ethyl acetate:

Tabulation:

S.No. Reaction

Time

(min)

Volume of

CH3COOH

(ml)

Volume

of NaOH

(ml)

CA(mol/lit)

XA M

)XM(1

XMln

A

A

1 5

2 10

3 15

4 20

5 256 30

7 35

8 40

9 45

10 50

Model Graph:



7/18

Model Calculation:

1) total

NaOHNaOH

A V

NV

C 0

=

2)VolumeSample

addedNaOHofmolesaddedCOOHCHofmolesC

3A

=

3)total

EAEAB

V

NVC 0

=

4)0

0

A

B

C

CM =

5)0

0

A

AA

A

C

CCX

=

6)00

AB CCSlopeK=

Result:

Thus the experiment on batch reactor II was performed. The order of the reaction was

verified and the value of k found the graph is

K =

**********


Time (min)x

0

Slope = K (CB0 CA0)

y

( )

A

A

X1M

XMln

7


8/18

MIXED FLOW REACTOR

Aim: To study the performance of a mixed 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, 2A

AA

KC

CCT

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 Ethylacetate =

Tabulation

S.No Sample

Volume (ml)

Burette Reading(ml) Volume of NaOH

consumed (ml)Initial Final

Model Calculation:

1.

2

NC

NaOHA

0=

2.( ) ( )[ ]

total

NaOHCOOHCHA

V

NVNVC

3 =

3.0

0

A

AAAexp

C

CCX

=

4. ( ) 2AAAtheo X1CkX0

=

Result:

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

Theoretically (XAtheo):

Experimentally (XAexp):**********


A0

A

A

X

X


9/18

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 0 =

2A2

A2A12

KCCC =

( )2AA0

A

X-1KC

X =

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 =

Flow rate of Ethylacetate =

Tabulation

For Reactor-I

S.No Sample

Volume (ml)



For Reactor-II

S.No Sample

Volume (ml)



Model Calculation:

NaOH

COOHCHCOOHCHNaOH

V

NVN

33 =



10/18

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

V11 =

( )21

AA0

A1

X-1KC

X =

Reactor II:

V

V22 =

( )

2

12

AA0

AA2

X-1KC

X-X =

Result:

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

found to be:

For Reactor-I

Theoretically :

Experimentally :

For Reactor-I

Theoretically :

Experimentally :

**********



11/18

PLUG FLOW REACTOR

Aim:

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

saponification of ethyl acetate.

Reaction:


Experimental setup:

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

Flow rate of Ethylacetate =

Tabulation:

S.No Sample

Volume (ml)



S.No Reactor volume

(ml)

Space time

(min)Titrant

volume (ml)

CA (N) XA (%)

(expt.)

XA (%)

(theo)



12/18

Model Graph:

Model Calculation:

1. CAo= NNaOH/2

2.

V =

3.( ) ( )[ ]

Volume

NVNVC

NaOHCOOHCHA

3 =

4.0A

AAexp

C

C1X =

5.0

0

A

AAtheo

KC1

CKX

+=

Result:

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

necessary graphs are drawn.

**********


Theoretical

Experimental

XA

x0

y

Time(min)

12


13/18

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.

Formulae:

1) ( )tiEtt ii=

2)2

ii2

i2 ttEt =

3)N

1

t

2

2

02 ==

where,

timeresidencemeant = variance2 =

ti = time interval

numberDispersionUL

D=

Standard data:

Normality of NaOH

Normality of Acitic Acid;

Flow rate of water

Tabulation:

Time

(min)

VNaOH(ml)

VCH3COOH(ml)

NNaOH

max

NaOH

N

N

F = dtdF

Ei =Eiti Eiti

2



14/18

Model Graph:

Model Calculation:

1.NaOH

COOHCHCOOHCH

NaOHV

NV

N

33 =

2. F=N/Nmax. =

3.dt

dFEi =

4. ( )tiEtt ii=

5.2

ii2

i2 ttEt =

6. 2

2

0

t

2 =

7.2

ULD

2

0=

8.N

120 =

Result:

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

were calculated.

**********


F E

y y

x xt t

14


15/18

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 NaOH

Normality of Acitic Acid;

Flow rate of water

Tabulation:

Time

(min)

VNaOH(ml)

VCH3COOH(ml)

NNaOH

max

NaOH

N

NF =

dt

dFEi =

Eiti Eiti2



16/18

Model Graph:

Model Calculation:1.

NaOH

COOHCHCOOHCHNaOH

V

NVN

33 =

2. F=N/Nmax. =

3.dt

dFEi =

4. ( )tiEtt ii=

5.2

ii2

i2 ttEt =

6. 2

2

0

t

2 =

7.2

UL

D 20=

8.N

120 =

Result:

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

N were calculated.

**********


F C

y y

x xt t

x x

yy

16


17/18

SEGREGATED FLOW REACTOR

Aim:

To calculate the performance of a tubular reactor as a segregated flow reactor for the

saponification of ethanol.

Reaction:


Theory:

In laminar flow in a tubular reactor, segregated flow occurs. The conversion is time

dependant as the element moves through the water. The conversion in each element of fluid

depends upon the residence time. Hence, to obtain average uniform conversion model equation

incorporating non ideal flow is used.

Procedure:

NaOH and ethyl alcohol at known concentrations are allowed to enter at a flow rate of

60 cc/min each into the reactors. Sufficient time is allowed to reach steady state. Samples arecollected drop by drop at different points. Concentration is found by the addition of acetic acid

and titration with NaOH.

From the volume and concentration of sample with NaOH, its concentration is found

out.

Formulae:

1)q

V =

2)0

0

A

AAAe

C

C-CX =

3)0A

A0AP

KC1

KCX

+=

4)

+=

0

0

0

21ln

21

A

A

AACK

CKCKX

seg

Standard Data:

Normality of NaOH :



Flow rate of NaOH =Flow rate of Ethylacetate =

Tabulation:

S.No Sample

Volume (ml)





18/18

S.No Reactor

volume (ml)

Space

time

(min)

Titrant

volume

(ml)

CA(mol/lit) XA(Plug) XA (Seg) XA(exp)

Model Calculation:

1. CAo= NNaOH/2

2.

V =

3. ( ) ( )[ ]Volume

NVNVC

NaOHCOOHCHA

3 =

4.0A

AAexp

C

C1X =

5.0

0

A

AAtheo

KC1

CKX

+=

6.

+=

0

0

0

21ln

21

A

A

AACK

CKCKX

seg

Model Graph:

Result:

Experiments were conducted in segregated flow and the conversions at various times were

calculated and graphs of conversion Vs time were drawn.

**********


XAP

XA

x0

y

Time (min)

XAS

XAe

18

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