Journal
of Engineering
andand
Applied
Sciences
, Vol.
3, 3,
Issue
(1)(1)
November,
2016
Journal
of Engineering
Applied
Sciences,
Vol.
Issue
May, 2016
Experimental Study of the Influence of Process Conditions on Tubular
Reactor Performance
M.K.
Al Mesfer
Al Mesfer,
M.K.
Chemical Engg. Deptt., College of Engineering, King Khalid University, P.O.Box 394 Abha 61411 KSA.
[email protected]
M. Danish*
Danish*,
M.
Chemical Engg. Deptt., College of Engineering, King Khalid University, P.O.Box 394 Abha 61411 KSA.
[email protected]
Abstract
This work presents an experimental study of the saponification reaction of ethyl acetate by sodium hydroxide in a tubular reactor at 1 atmosphere (atm) of pressure. The objective of this study
is to analyze the effect of operating conditions on the rate constant and conversion in order to explore the tubular reactor performance. The temperature, reactant flow rate, and residence time are
the parameters considered for analyzing the reactor performance. The steady-state conversion is
achieved after a period of 30 minutes. Conversion decreases with the increased reactant flow rate,
owing to the resulting decrease in residence time. The rate constant first decreases and then increases with feed flow rate. The rate constant and conversion increase with increased temperature
within the studied temperature range. The residence time declines with increased reactants flow
rates leading to decreased NaOH conversion. The obtained NaOH conversion values at different
temperatures have been compared with literature data. The outcomes of this study may be useful
in maximizing the conversion of ethyl acetate saponification reaction for industrial scale synthesis
.of sodium acetate and ethanol synthesis in a tubular reactor
Keywords: Saponification; Plug flow reactor (PFR); Conductivity; Conversion; Hydrolysis.
Article history: Received: May 04, 2016, Accepted: November 08, 2016
1. Introduction
Several types of reactors are used
in chemical or petrochemical industries.
Plug flow reactors (PFRs), also known as
continuous tubular reactors, play a key role
in chemical industries. Tubular reactors are
often used when continuous operation is
required but back-mixing of products and
reactants is not desired. The use of plug flow
reactors becomes especially important when
continuous large-scale production is needed.
PFRs are associated with high volumetric unit
conversion because the occurrence of side
reactions is minimal. In plug flow reactors,
reactants are fed from one end of reactor
and flows continuously through the length of
reactor as a series of plugs and the products
are discharged from the other end of reactor.
Advantages of PFRs include high
volumetric unit conversion and the capability
of running for longer periods without any
maintenance or less maintenance. For the
same conversion and reaction conditions,
PFR volume is usually lower than CSTR
volume for isothermal reactions greater than
zero order (Fogler, 2006). For the industrial
Al Mesfer, M.K. and Danish, M.: Experimental Study of the Influence of Process Conditions on Tubular Reactor Performance
17
Journal
of Engineering
andand
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Sciences
, Vol.Vol.
3, Issue
(1) (1)
November,
2016
Journal
of Engineering
Applied
Sciences,
3, Issue
May, 2016
application, PFRs can be assembled as a
single long tube or in the form of a coil.
PFRs are extensively used in the industry
for gaseous/liquid phase systems. PFRs are
commonly used for gasoline production, oil
cracking, oxidation of sulphur dioxide to
sulphur trioxide, synthesis of ammonia and
polymer manufacturing along with other
applications.
According to Bursali et al., 2006, the
hydrolysis of a fat or oil in alkaline condition
produces soap and the reaction that occurs in
alkaline conditions is known as saponification.
Hydrolysis of an ester to produce an alcohol
and the salt of a carboxylic acid, under basic
conditions, is called saponification and it is
normally referred as the reaction of antacid
in the presence of fat/oil to produce soap.
Saponification is the hydrolysis of ethyl
acetate by sodium hydroxide to produce
sodium acetate and ethanol. A lot of studies
are available in the literature on the process
improvement of this saponification reaction.
The effect of operating conditions on CSTR
performance for ethyl acetate saponification
has been investigated experimentally by
Danish et al., 2015. The parameters selected
for analysis were temperature, feed flow rate,
residence time, reactor volume and stirrer
rate. It was found that conversion decreases
with increased flow rate due to decrease of
residence time and agitation rate has a positive
effect on the conversion and rate constant. It
was also concluded that specific rate constant
and conversion increases with increased
temperature within the studied range.
18
The hydrolysis of ethyl acetate is one
of the most important reactions, and it is
characterized as second-order reaction in
the literature (e.g. Kapoor, 2004). Various
measurement techniques (Daniels et al.,
1941; Schneider et al., 2005) have been
used by several investigators at different
temperatures to study saponification reaction.
The techniques depend on the conductometric
measurements to evaluate the composition at
any time was reported by Walker, 1906 and
this measurement approach circumvents
regular removal of product samples for
analysis.
Tsujikawa et al. 1966 estimated the rate
constant and activated energy at an initial
temperature of 25 oC as 0.112x10-3 m3/mol.
sec and 8.37 KJ/mol respectively for alkaline
hydrolysis of ethyl acetate in a polyethylene
batch reactor. It was also observed that the
reaction rate reaction rate of ethyl acetate
saponification is not expressed adequately
by a second-order rate equation as given in
literature (e.g Kapoor, 2004).
Other investigators focused their attention
on online data recording, using a conductivity
measurement technique to make the
procedure much simpler. Researchers have
conducted several studies on saponification
reaction; the data exhibit wide scatter for the
saponification of ethyl acetate with sodium
hydroxide. Kuheli et al. 2011 conducted
studies on the saponification of ethyl
acetate by utilizing innovative conductivitymonitoring instruments. Rate constants
of the saponification reaction at various
Al Mesfer, M.K. and Danish, M.: Experimental Study of the Influence of Process Conditions on Tubular Reactor Performance
Journal
of Engineering
andand
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, Vol.
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November,
2016
Journal
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May, 2016
temperatures (range, 35°C to 55°C) were
evaluated, and observed that outcomes were
in agreement with some of the data reported
in literature.
Ahmad et al. 2013 carried out a
comparative study of ethyl acetate hydrolysis
using full two level factorial design in batch
(volume: 1x10-3 m3 and plug flow reactors
(volume: 0.4 x10-3 m3). The maximum
fractional conversion of 0.97 was obtained at
a residence time of 300 seconds in both type
of reactors under optimum concentrations
of NaOH (0.01 mol/L) and CH3COONa
(0.07 mol/L). It was also concluded that
reaction conversion increases positively with
increased absolute initial concentration of
CH3COOC2H5.
Saponification of ethyl acetate by sodium
hydroxide to optimize the conversion in
a continuous stirred tank reactor (CSTR)
has been studied using two level factorial
design and response surface methodology by
Ullah et al., 2015. The maximum conversion
of 96.71 % was obtained corresponding
to sodium hydroxide and ethyl acetate
concentration of 0.01 mol/L and 0.1 mol/L
while it was suggested that the influence of
feed ratio, agitation rate and temperature was
insignificant which contradicts the findings (
effect of reaction temperature on conversion)
of other researchers (Wijayarathne et al.,
2014; Danish et al., 2015). On other hand,
the reactants concentration to maximize the
conversion of sodium hydroxide reported
by Ahmed et al. 2013 was different from the
concentrations calculated by Ullah et al. 2015.
A comparative study of ethyl acetate
saponification and an-oxidation-reduction
reaction has been conducted in a batch and
semibatch reactor by Grau et al., 2002. It was
concluded that it is practicable to operate the
reactor in both modes of operation to study
the saponification reaction.
Hydrolysis of ethyl acetate by sodium
hydroxide in a tubular reactor using Aspen
Plus has been investigated by Wijayarathne
and Wasalathilake, 2014. The simulated
results were verified by the experimental data
and it proves that predicted results were in
agreement satisfactorily with experimental
results. The model developed can be used as
a reference to comprehend reaction kinetics
of plug flow reactor. The objective of the
current study is to investigate the influence
of operating conditions on tubular reactor
performance using hydrolysis of ethyl acetate
by sodium hydroxide. The temperature,
reactant flow rates and residence time are
the parameters considered for analyzing
the influence on steady-state conversion of
NaOH and rate constant. The obtained result
of sodium hydroxide conversion as a function
of temperature of reaction mixture has been
compared with literature data (Wijayarathne
et al. 2014) in order to validate the outcome
of current study.
2. Materials and methods
2.1 Chemicals
Analytical-grade reagents (AR) were used
to carry out the research work. Ethyl acetate
of purity 99.5% and sodium hydroxide of
Al Mesfer, M.K. and Danish, M.: Experimental Study of the Influence of Process Conditions on Tubular Reactor Performance
19
Journal
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, Vol.Vol.
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Journal
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May, 2016
concentration 98.0%-100% were utilized to
conduct the experiments. The distilled water
generated using distilled water unit (Type
2008,GFL) was used to prepare the solutions
of sodium hydroxide NaOH (~0.1 M) and
ethyl acetate CH3COOC2H5 (~0.1 M).
2.2 Experimental Setup
The tubular reactor (reactor coil:
length—20.9 m; internal diameter—5.0x10-3
m; total volume of reactor V—0.41x10-3 m3)
obtained from Armfield (U.K.) has been used
for the experiments for the investigation
as shown in Fig.1 and designed properly to
facilitate the detailed study.
The tubular reactor in which the chemical
reaction takes place made up of a pliable
coil. The volume of the reactor in the form
of coil is 0.41x10-3 m3. The conductivity
and temperature sensors are inserted into
the gland for online data acquisition. In
order to conduct an experiment at a fixed
temperature, the reactor coil is immersed
in water, which is maintained at a fixed
temperature by temperature controller. Water
enters the reactor through non-return valve
and this valve prevents water draining back
from reactor when pump is under switch off
position.
The reactants i.e. NaOH and CH3COOC2H5
enter the reactor coil from one end and leave
the reactor vessel through the other end of the
coil. The conductivity probe housing allows
the conductivity probe to be fixed in the
stream of products mixture coming out from
the reactor coil. The progress of the hydrolysis
reaction is recorded by conductivity probe
as the conductivity of solution varies with
conversion. The conductance of the reaction
mixture varies with conversion. Priming
vessel attached with reactor service unit is
used to fill the reactor coil and returned back
into the hot water circulator system. The
reactants flow rates from the storage vessel
Fig. 1: Setup diagram of tubular reactor (adopted from Armfield, U.K.)
20
Al Mesfer, M.K. and Danish, M.: Experimental Study of the Influence of Process Conditions on Tubular Reactor Performance
conducting the experiments; and the saponification
reaction were performed at a fixed temperature of
30°C. Conductance of reaction mixture was recorded
at 5-minute intervals until steady-state condition was
reached.
The
steady-state
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30 minutes as shown in Fig.2.
3. Results and Discussion
3.1 Steady-State Condition
Feed flow rates of 13.33x10-7 m3/
sec sodium hydroxide and 13.33x10-7 m3/
sec ethyl acetate were fixed using peristaltic
pumps. Solutions of 0.1M NaOH and 0.1M
CH3COOC2H5 were used for conducting the
experiments; and the saponification reaction
were performed at a fixed temperature of 30°C.
Conductance of reaction mixture was recorded
0.84
Conductivity λt ( Siemens/m)
2.3 Experimental Procedure
Solutions of sodium hydroxide and
ethyl acetate were prepared to perform
the experiments under different process
conditions. Two peristaltic pumps were used
to pump the reactant from feed tanks and enter
the reactor vessel. The reactants pass through
pre-heating coils submerged in the water;
here, the reactants are individually brought
up to the desired reaction temperature. The
reactants are mixed together at the inlet of
reactor coil and reaction proceeds as reaction
mixture pass through the reactor coil.
After acquiring the required process
conditions in the reactor, actual-time
conductivity was recorded by the probe
and displayed on control panel. The degree
of conversion and hence, rate constant
are tabulated by utilizing the conductivity
data. One of the products of saponification
reaction i.e. the sodium acetate ascribes for
the conductivity after infinite time.
0.9
0.85
Conductivity λt (Siemeens/m)
are controlled by using two peristaltic pumps;
these pumps are calibrated so that any desired
reactants flow rate can be adjusted.
fixed tem
data were
shows th
with vario
0.83
0.82
0.81
0.8
0.79
0.78
0.85
0.8
0.75
0.77
0.76
0.75
0
3
6
Time t
9
x10-2
12
15
0.7
18
(sec)
Fig.2:
Conductivity
versus
curve
for
Fig.2: Conductivity
versus time
curve fortime
CH3COOC
2H5
hydrolysis by NaOH
CH3COOC2H5 hydrolysis by NaOH
Sodium hydroxide
sodium
acetate contributed
at 5-minute
intervalsand
until
steady-state
condition
conductance to the reaction mixture and on the other
was
The and
steady-state
condition
hand,reached.
ethyl acetate
ethyl alcohol
do not. was
The
sodium
hydroxide
solution
conductivity
at
a
given
reached after 30 minutes as shown in Fig.2.
concentration and temperature is not equal to that of
Sodium
and sodium
at the same concentration
and
CH3COON
A solutionhydroxide
reaction conversion.
acetate contributed conductance to the
The rate
constantand
andonreaction
conversion
were
reaction
mixture
the other
hand, ethyl
calculated at steady-state conditions. Reaction mixture
acetate
and ethyl
alcohol
not.asThe
conductivity
decreases
with do
time
the sodium
reaction
proceeds, and
it attains
a steady-state
of
hydroxide
solution
conductivity
at avalue
given
conductivity after approximately 30 minutes. This
concentration
not equal
occurs because and
as temperature
the reaction is
proceeds,
the
concentration
NaOHsolution
decreases,
resulting
to
that of CHof
COON
at
the
same
3
A
indecreased conductivity
values. A conversion of
concentration
and
conversion.
sodium hydroxide
X reaction
~ 0.727; and
rate constant k ~
1.27x10-3 m3/mol.sec were obtained under steady state
The rate constant and reaction conversion
conditions.
were calculated at steady-state conditions.
Reaction mixture conductivity decreases
with time as the reaction proceeds, and it
attains a steady-state value of conductivity
after approximately 30 minutes. This
occurs because as the reaction proceeds,
the concentration of NaOH decreases,
resulting indecreased conductivity values. A
conversion of sodium hydroxide X ~ 0.727;
and rate constant k ~ 1.27x10-3 m3/mol.sec
were obtained under steady state conditions.
Al Mesfer, M.K. and Danish, M.: Experimental Study of the Influence of Process Conditions on Tubular Reactor Performance
21
6.5
Fig.3: Effe
conversion
The co
upto 0.81
equal to
Siemens/
decrease
rate signi
The conv
flow rate
flow rate
value of X
Reside
flow rate
of 10.0x1
ethyl ace
reactants
resulting
reactants
practical
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0.6
0.85
0.55
0.8
0.5
0.75
OC2H5
contributed
n the other
o not. The
at a given
l to that of
tration and
rsion were
on mixture
e reaction
value of
nutes. This
ceeds, the
resulting
version of
onstant k ~
steady state
0.7
0.45
6.5
7
7.5
8
8.5
9
9.5
10
10.5
Reactants flow rate F x 107 (m3/sec)
Fig.3: Effect of reactant flow rates on conductivity and
Fig.3:
Effect of reactant flow rates on conductivity
conversion
and conversion
The conductivity increases with reactant flow rate
upto 0.818 Siemens/m at flow rates of both reactants
The toconductivity
increases
with with
reactant
as compared
0.773
equal
10.0x10-7 m3/sec
-7
3
m
/sec.
Siemens/m
at
a
flow
rate
of
6.67x10
flow rate upto 0.818 Siemens/m at flowA
decrease of conductivity with an increased feed flow
-7
rates
of both the
reactants
equal
to desired
10.0x10
m3/
rate signifies
formation
of less
products.
The conversion curve shows a decline with increased
sec
as compared with 0.773 Siemens/m at
flow rate. Conversion reaches a value of X~ 45% at a
-7
-7
m3/sec
comparison
with a
of of
10.0x10
a flow
flowrate
rate
6.67x10
m3in/sec.
A decrease
value of X~ 58 % at a flow rate of 6.67x10 -7 m3/sec.
of conductivity with an increased feed flow
withofincreased
reactant
rate Residence
signifies time
the decreases
formation
less desired
flow rate and reaches a value of 205 sec at a flow rate
-7
products.
conversion
curvehydroxide
shows and
a
m3/sec
of both sodium
of 10.0x10The
ethyl
acetate,
as
shown
in
Fig.4.
As
flow
rates
decline with increased flow rate. Conversionof
0.22
Residence time vs.reactant
flow rate
0.21
Rate constant vs. reactant flow
rate
0.2
300
280
0.19
260
0.18
0.17
240
0.16
220
200
0.4
temperat
specific r
0.15
6.5
7.5
8.5
9.5
10.5
0.14
Reactants flow rate F x 107 (m3/sec)
Fig. 4: Variation of residence time and rate constant with
reactants flow rate
Fig. 4: Variation of residence time and rate constant
Temperature
with3.3
reactants
flow rate
The experiment was conducted at a flow rate of
-7
3.3 Temperature
m3/sec for both reactants i.e., NaOH and
10.0x10
CH3COOC2H5. Concentration of both reactants was
The experiment was conducted at a flow
adjusted equal to 0.1 M NaOH and 0.1 M
-7
of both
rate reactants
constant i.e.,
and
CH3COOC
2H5. Variation
rate
of 10.0x10
m3/sec for
conversion with temperature is shown in Figure 5. It is
NaOH
and
COOC
H . Concentration
of
found that
theCH
reaction
conversion
is a strong function
3
2 5
of
reaction
temperature,
and
variation
is
almost
linear.
both reactants was adjusted equal to 0.1 M
1.2 and 0.1 M CH COOC H Variation
0.75of
NaOH
3
2 5.
Rate constant vs.
rate 1.1
constant and
conversion with temperature
temperature
0.7
1
is shown
in Figure
5. It is found that the
Conversion vs.
0.9
0.65
temperature
reaction
conversion is a strong function of
0.8
reactants are increased, residence time decreases,
0.7
0.6
resulting in decreased conversion value. Thus higher
Al Mesfer, M.K. and Danish, M.: Experimental Study of the Influence of Process Conditions on Tubular Reactor Performance
0.6
22
reactants
flow rates are not always desirable for
0.55
practical application.
0.5
Conversion X
18
320
Conversion X
Conductivity λt ( Siemens/m)
Conversion vs. flow rate
Residence time tR (sec)
Conductvity vs. flow rate
Rate constant k x103 (m3/mol.sec)
0.9
of X~ 58 % at a flow rate of 6.67x10-7 m3/sec.
Residence time decreases with increased
reactant flow rate and reaches a value of
205 sec at a flow rate of 10.0x10-7 m3/sec of
both sodium hydroxide and ethyl acetate, as
shown in Fig.4. As flow rates of reactants are
increased, residence time decreases, resulting
in decreased conversion value. Thus higher
reactants flow rates are not always desirable
for practical application.
0.4
0.3
0.5
The re
reaction
reported
6. Result
obtained
reactor
conversio
higher (8
obtained
be due t
lower re
time incr
to increa
The effec
performa
researche
suggested
temperat
Wijayara
0.85
0.8
0.75
Conversion X
ached after
reaches a value of X~ 45% at a flow rate of
10.0x10-7 m3/sec in comparison with a value
Rate constant k x 103
(m3/mol.sec)
3.2 Reactant Flow Rate
Influence of the flow rates of NaOH and
urnal of Engineering and Applied Sciences 00 (00) 000–000
CH3COOC2H5 on the conversion and rate
constant were investigated. Three different
Reactant Flow Rate
feed3.2flow
rates (i.e. 6.67x10-7 m3/sec,
8.33x10-7
m3/sec
and flow
10.0x10-7
were
Influence
of the
rates m3/sec)
of NaOH
and
CH3COOC2H5 on the conversion and rate constant
selected
to analyze
thedifferent
reaction
were investigated.
Three
feedperformance
flow rates (i.e.
ec sodium
-7
m3/sec, 8.33x10
m3/sec andat 10.0x10
6.67x10
cetate were
and
the experiments
were-7conducted
a fixed -7
m3/sec) were selected to analyze the reaction
s of 0.1M
temperature
Actual-time
performance of
and30°C.
the experiments
wereconductivity
conducted at a
used for
°
C.
Actual-time
conductivity
fixed
temperature
of
30
onification
data were collected with the different flow
rates.
data were collected with the different flow rates. Fig.3
perature of
Fig.3
the variation
of conductivity
and
showsshows
the variation
of conductivity
and conversion
as recorded
with variouswith
reactant
flow rates.
ndition was
conversion
various
reactant flow rates.
0.7
0.65
0.6
0.55
0.5
0.45
0.4
25
Fig.6: Com
temperatu
suggested that conversion increases with increased
temperatures of reaction mixtures (Ullah et al., 2015;
Wijayarathne et al., 2014).
3.3 Temperature
Reactants flow rate F x 107 (m3/sec)
0.4
Conversion X
0.5
Fig. 4: Variation of residence time and rate constant with
reactants0.3
flow rate
0.2
3.3 Temperature
25
30
0.45
35
Temperature T (0C)
40
45
Conversion X
Rate constant k x103 (m3/mol.sec)
The experiment
was conducted
at a flow rate of
ture is more profound
than the change
with
-7
3
m
/sec
for
both
reactants
i.e., NaOH and
rate constant. 10.0x10
Fig.5:
andversus
conversion
versus
Fig.5:
RateRate
constantconstant
and conversion
temperature curves
CH3COOC2H5. Concentration of both reactants was
curves
adjusted
equaltemperatures
to
0.1 M NaOH and 0.1 M
esults obtained
attemperature
different
Conversion
varies fromof52.6% at a temperature of
of rate constant and
3COOC
2H5. Variation
mixture haveCH
been
with
°compared
temperature of 40 °C. The rate
30 C to 73.4% at afindings
conversion
withastemperature
is shown in Figure 5. It is
by Wijayarathne
et
al.
2014
shown
in
Fig.
constant of the saponification reaction increased from
that the reaction
conversion
is a strong
function
varies
52.6%
ts reported byfound
Wijayarathne
et3/mol.sec
al. 2014
were
-3 from
m
to
1.081x10
m3/mol.sec
with
0.228x10-3Conversion
-7
3 and variation is almost linear.
of
reaction
temperature,
m
/s
with
a
under a flow rate
of
6.67x10
°
°
an
increased
temperature
from
30
C
to
40
at
a
temperature
of
30
C
to
73.4%
at°Ca
-3
3
m
.
The
NaOH
volume of 0.44x
10
respectively.
The change
in conversion
1.2
0.75 with
on reported by Wijayarathne
al. 40
2014°C.
is The rate constant
temperatureet of
of
o
Rate
constant
vs.
compared with
the value
80 % at 40 C) 1.1
temperature
the
saponification
reaction increased
0.7 from
in present study (73.4
%
at 40 oC) and it may
1
-3 mixture
to the large volume
of reaction
Conversion
vs. and
0.228x10
m3/mol.sec
to 1.081x10-3 m3/
0.9
0.65
temperature
eactant flow rate compared with.
Residence
0.8
mol.sec
with
an
increased
temperature
from
reases with decreased flow rate and this leads
0.7
0.6
.
ased reaction conversion
30 °C
to 40 °C respectively. The change
0.6
ct of reaction mixture
temperatures
reactortemperature is
0.55 more
in
conversiononwith
0.5
ance have not been explored by the
profound
than theit change
with specific
rate
0.4 2013) although
ers (Ahmed et al.
was
0.5
0.3increases with increased
d that conversionconstant.
tures of reaction mixtures
(Ullah et al., 2015;
0.2
0.45
The30 results
at45 different
35 obtained
40
athne et al., 2014). 25
5
T
temperatures Temperature
of reaction
mixture have
been compared with findings reported by
Fig.5: Rate constant and conversion versus temperature curves
Wijayarathne et al. 2014 as shown in Fig. 6.
Conversion varies from 52.6% at a temperature of
Results
reported
by Wijayarathne
et al.rate2014
to 73.4%
at a temperature
of 40 °C. The
30 °C
constant
of
the
saponification
reaction
increased
from -7
were obtained under a flow rate of 6.67x10
0.228x10-3 m3/mol.sec to 1.081x10-3 m3/mol.sec with
-3
3
°
m3/s withtemperature
a reactor volume
an increased
from of
300.44x
C to1040m°C. The
respectively.
The change
in conversion with
NaOHCurrent
conversion
work (Volume reported by Wijayarathne
V=0.41 L)
et al.Wijayarathne
2014 etisal. 2014
higher
(80 % at 40 oC)
(
Volume V=0.44 L)
compared with the value obtained in present
(0C)
30
Temperature T (oC)
The
of reaction
mixture temperatures
on reactor
et effect
al. 2013)
although
it was suggested
Fig.6: Comparison
conversion
at different
performance
have of NaOH
not been
explored
by the
of reaction
mixture withwith
literature
data
thattemperatures
conversion
increases
increased
researchers
(Ahmed
et
al. 2013) although
it was
(Wijayarathne
et al. 2014)
suggested
that
conversion
increases
with
increased
temperatures of reaction mixtures (Ullah et
temperatures
of reaction mixtures (Ullah et al., 2015;
Conclusions
al.,4.2015;
Wijayarathne
Wijayarathne
et al., 2014). et al., 2014).
In this investigation, hydrolysis of ethyl acetate (~0.1
0.85 with sodium hydroxide (~0.1 M) has been studied.
M)
The advancement of the saponification reaction was
0.8
observed by monitoring conductivity data under
different
process conditions. Sodium hydroxide and
0.75
sodium acetate impart conductance to the hydrolysis
0.7
reaction. Experiments were performed at a pressure of
10.65
atmosphere (atm) and a concentration of 0.1 M of
both reactants. The influence of operating conditions
Conversion X
0.5
Conversion X
Rate constant k x 103
(m3/mol.sec)
Rate constant k x103 (m3/mol.sec)
Residence time tR (sec)
The experiment was conducted at a flow rate of
10.0x10-7 m3/sec for both reactants i.e., NaOH and
temperature
isIssue
more
profound
than the change with
0.85
Journal
of Engineering
andand
Applied
, Vol.
3, 3,
Issue
(1)(1)
November,
2016
ofEngineering
both reactants
was Sciences
CH3COOC2H5. Concentration
Journal
of
Applied
Sciences,
Vol.
May, 2016
specific
rate
constant.
320
0.22
adjusted
equal to 0.1 M NaOH and
0.1 M
0.8
Residence time vs.reactant
COOC
H
Variation
of
rate
constant
and
CH
3
2temperature,
5.
flow rate and variation
reaction
0.21is almost
study
(73.4 obtained
% at 40atoC)
and ittemperatures
may be due
The 0.75
results
different
of
300
conversion
with temperature
is reactant
shownflow
in Figure 5. It is
Rate constant vs.
reaction
mixture
have
been
compared
with
findings
rate
linear.
to the large volume of reaction mixture and
0.2 function
found
that the reaction conversion is a strong
reported0.7by Wijayarathne et al. 2014 as shown in Fig.
of
280reaction temperature, and variation is almost linear.
lower
reactant
flow
rate compared
6.
Results
reported by
Wijayarathne
et al. 2014 with.
were
0.19
0.65
-7
m3/s with a
obtained
under
a
flow
rate
of
6.67x10
1.2
0.75
Residence time increases with decreased
260
0.18
reactor 0.6volume of 0.44x 10-3 m3. The NaOH
Rate constant vs.
1.1
Current
(Volumeis
temperature
conversion
reported
Wijayarathne
et work
al.reaction
2014
flow rate
and
this by
leads
to increased
0.7
0.17
0.55
V=0.41 L)
1
240
with theet al.
value
higher (80 % at 40 oC) comparedWijayarathne
2014 (
conversion.
o
Conversion vs.
0.9
0.5
0.16
C)
and
it
may
obtained
in
present
study
(73.4
%
at
40
Volume
V=0.44
L)
0.65
temperature
be due toThe
the large
volume
reaction mixture
and
220 0.8
effect
of of reaction
mixture
0.45
0.15
lower
reactant
flow
rate
compared
with.
Residence
0.7
0.6
temperatures
ondecreased
reactor flow
performance
0.4
time
increases
with
rate and this have
leads
200
0.14
0.6
25reaction conversion
30
35
40
45
6.5
7.5
8.5
9.5
10.5
.
to
increased
not
been
explored
by
the
researchers
(Ahmed
0.55
0.6
Current work (Volume
V=0.41 L)
Wijayarathne et al. 2014 (
Volume V=0.44 L)
0.55
0.5
0.45
0.4
25
30
35
40
Fig.6:
of NaOH
conversion
at different
Fig.6:Comparison
Comparison
of NaOH
conversion
at different
temperatures
of reaction
mixture mixture
with literature
data
temperatures
of reaction
with
literature
(Wijayarathne et al. 2014)
data (Wijayarathne et al. 2014)
4. Conclusions
In
investigation, hydrolysis of ethyl acetate (~0.1
4. this
Conclusions
M) with sodium hydroxide (~0.1 M) has been studied.
In this ofinvestigation,
hydrolysis
of
The advancement
the saponification
reaction was
observed
by monitoring
conductivity
data under
ethyl acetate
(~0.1 M) with
sodium hydroxide
different process conditions. Sodium hydroxide and
(~0.1 M)
has impart
been studied.
Thetoadvancement
sodium
acetate
conductance
the hydrolysis
reaction. Experiments were performed at a pressure of
of the saponification reaction was observed by
1 atmosphere (atm) and a concentration of 0.1 M of
both
reactants.conductivity
The influence of
operating
monitoring
data
under conditions
different
process conditions. Sodium hydroxide and
sodium acetate impart conductance to the
Al Mesfer, M.K. and Danish, M.: Experimental Study of the Influence of Process Conditions on Tubular Reactor Performance
35
40
Temperature T (oC)
mparison of NaOH conversion at different
ures of reaction mixture with literature data
45
45
Temperature T (oC)
23

range of temperatures.
The specific rate constant also increases with
increased temperature but not as profoundly as
does conversion.
Journal
of Engineering
andand
Applied
Sciences
, Vol.Vol.
3, Issue
(1) (1)
November,
2016
Journal
of Engineering
Applied
Sciences,
3, Issue
May, 2016
hydrolysis reaction. Experiments were
performed at a pressure of 1 atmosphere (atm)
and a concentration of 0.1 M of both reactants.
The influence of operating conditions such
as reactant flow rate, residence time, and
temperature on conversion and specific rate
constant has been analyzed. The research
outcomes may be outlines as follows:
•
Decline in the value of actual
•time
Decline
in thewith
value
actual the
time
conductivity
time of
signifies
conductivity
with time
signifies the
progress
of the hydrolysis
reaction.
of the hydrolysis
reaction.
• progress
A steady-state
conversion
value of
• A and
steady-state
conversion
valueto of
72.7%
specific rate
constant equal
72.7%mand
specific
rateachieved
constantafter
equal
1.27x10
/mol.sec
were
1.27x10-3
timetointerval
of 30m3/mol.sec
minutes. were achieved
• afterThe
reaction
conversion
time interval
of 30 minutes.
diminishes
with anconversion
increased diminishes
reactant
• The reaction
flowwith
rate;anthis
is due reactant
to the decrease
increased
flow rate;ofthis
residence
is due time.
to the decrease of residence time.
•
the hand,
other the
hand,
the ratefirst
• On On
the other
rate constant
constant
first decreases
then increases
decreases
and then and
increases
within the
within
the studied
of reactant
flow
studied
range ofrange
reactant
flow rates.
•rates.
Conversion increases almost linearly
• withConversion
temperature, increases
from 0.526 almost
to 0.734
linearly
with
temperature,
from
0.526
for a temperature change from
30°C
to 0.734
for
a
temperature
change
from
to 40°C. The maximum factional
30°Cconversion
to 40°C. The
maximum
factional at
of 0.734
was achieved
conversion of 0.734 was achieved at a
a temperature of 40 oC under studied
temperature of 40 oC under studied range
range of temperatures.
of temperatures.
• The specific rate constant also increases
•
The specific rate constant also
with increased temperature but not as
increases with increased temperature but
profoundly as does conversion.
not as profoundly as does conversion.
-3
3
Acknowledgement
The authors are thankful for the support of
24
Grau
Schn
Acknowledgement
the laboratory staff at King Khalid University,
The authors are thankful for the support of the
Abha
KSA.staff at King Khalid University, Abha KSA.
laboratory
Tsuj
Nomenclature
Nomenclature
Ulla
M
V
F
X
tR
k
T
t
Reactants concentration
Volume of reactor
Reactant flow rate
Reaction conversion
Residence time
Rate constant
Temperature
Time
mol/liter
m3
m3/sec
(-)
sec
m3/mol.sec
o
C
sec
Wija
Wal
Greek Symbols
λ
Conductivity
Siemens/m
References
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25