this report made by koya university student of chemical engineering (shwan sarwan ).

1. Continuous stirred tank reactor (CSTR):
Conductivity measurement
Name of student: Shwan Sarwan Sadiq
Group: B
Date of Exp. OCT 28th
2015
Submission date: NOV 11th
2015
Supervisor: ms.lameha
Chemical Engineering Department
Chemical reactors lab
3rd stage
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2. Table of content:
Aim of the experiment 3
Theory 4 &5
Apparatus 6&7
Methodology
8,9,10,11,12,13,14,15,16,17,18
Data sheet 19
Graphs 20
Discussion 21,22&23
References 24

3. Aim of the experiment:
Measurement of the conductivity for a base – water
Mixture along time at high temperature using different
Concentrations.

4. Theory:
CSTR:
_it’s called ‘mixed reactor ‘, ‘back mix reactor’, ‘Continuous stirred
Tank reactor CSTR ‘. It’s a reactor in which contents are
well mixed And uniform throughout. Thus, the exit stream
from the reactor has the same composition as the fluid
within the reactor. The pattern of flow is mixed flow and is
used primarily for liquid phase reactions.
More specifically, continuous stirred tanks are used for
relatively slow reactions of liquids and slurries. .
_Its normal operation is at steady state, where the conditions
in the
Reactor don't change with time and it’s assumed to be
perfectly mixed,
So the contents have relatively uniform properties such as
temperature, Density, etc.
Conductivity:
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

5. Continue..
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.
_In conductivity works, it is necessary to work with as pure
As possible solvents because any impurity affects to
Conductivity therefore, the distilled water has to be used
During the experiments rather than tap water.

6. Apparatus:
To study CSTR reactor, it is necessary to use a service
Module and Interface called QUSC. This unit provides the
reagents and the thermostatized water to the reactor under
study.
Base module and interface, QUSC:
QUSC. Service Unit:
_This unit is common for the Chemical Reactors, and can
work with one or several reactors.
_ Accommodation and exchange system of the reactors,
quick and easy to handle.
_It supplies all the services for the operation of each reactor
_ Anodized aluminum structure and panels of painted steel.
_ Main metallic elements in stainless steel.
_ Diagram in the front panel with similar distribution to the
elements in the real unit.

7. Continue..
_2 Peristaltic dosing pumps with variable speed. Flow rate
up to 3 l. /h.
(Unit standard disposition). With another disposition, they
could reach a flow rate up to 10 l./h.
_ Thermostatic bath of 6 l. capacity. Temperature control of
hot water in order to maintain the reactor temperature.
_Pump of 3 l. /min., to impel the thermostatization water
from the bath to the reactor.
_2 Tanks for the reagents, of 1 l. capacity each one, made in
Pyrex glass.
_The control of the reaction is carried out by a conductivity
sensor,
Which allows the reaction evolution parameterization in real
time.
_ Three “J” type temperature sensors, one to know the
thermostatic
bath temperature in a continuous way and two sensors
to know the

8. Continue..
Water temperature at the thermostatic bath water inlet and
outlet.
_ Quick connectors with shutoff valve that enable an easy
coupling of
The Service Unit to the chosen reactor.
_All elements of this unit are chemically resistant.

9. Continue..
Electronic Console:
Metallic box.
_ Temperature sensors connectors.
_ Digital display for temperature sensors.
_ Selector for temperature sensors.
_ Peristaltic pumps controllers and switches.
_ Water pump switch.
_ Stirrer switches.
_heating element controller.
The reagents supply circuit is constituted by a PTFE pipe of 6
mm. The reagents are introduced into two Pyrex vessels
of 1 liter each placed at the rear part. There are two

10. Continue..
Peristaltic pumps to move the reagents. The following valves
are located at the Module’s base:
_The 6 mm valves (1) are mounted at the peristaltic
pumps outlet and they must be connected to the reagent
inlet of the Reactor.
_The ball valves with the mark (2) are of water outlet and
inlet.

11. Continue..
They have a tube of 8 mm which must be connected to
the water inlet and outlet of the reactors. The
connections are Interchangeable between them.
_The temperature control system consists of a thermostatic
Bath, whose temperature is controlled by means of a PID
Control on this bath temperature. The thermostated water
System is also composed of a thermostatization water
impeller pump, with variable flow by means of the valves (2).
_The data acquisition and process control system is
Centralized in the electronic interface connected to the
different elements which constitute both the base
module and the reactor module.
Continuous Stirred Tank Reactor Module:
The body of the reactor, made in Pyrex glass, has a capacity
of 2 liters and it is specially designed to work in
continuous, although it also allows to work in discontinuous
if the reagents are introduced to the desired volume and

12. Continue..
the pump are stopped. There is a manual discharge valve at
the lower part for this purpose.
_During the operation in continuous, the final product outlet
is carried out by the stainless steel tube (4) which is
regulable in height, loosening the brass nut.
This allows to work with different reaction volumes.
_The stirring system (1) with speed control and indication
allows The study of the influence of both continuous and
discontinuous Agitation in the reaction kinetics.

13. Continue..
_ System to heat the reaction formed by a stainless steel coil
(3) through which the water from the Service Module bath
circulates. The water inlets to the coil from the service
module will be done through the fittings of 8 mm placed
at the lower part of the reactor.
_The monitoring of the reaction is carried out using a
conductivity cell with conductivity meter, which allows
measuring the evolution of the reaction in real time.
_The thermostatic bath has been designed to keep constant
the temperature around the reactor. A volume of 9 liters has
been taken, because this volume allows the control of the
temperature of water every 0.1ºC.

14. Continue..
The conductivity meter or conductivity sensor:
Applies a temperature compensation factor by default to
Compensate for the change of the measurement due to
Temperature. Such factor has a factory-set value of 2%,
which
implies a correction of 2% per degree increased with respect
to the reference temperature. Depending on the practical
exercise to be performed, we may want this value be 0%, so
that it does not compensate for the temperature influence
(when we want to study ionic conductivities) or have a
specific value between 0 and 5% (when we want to

15. Continue..
associate conductivity and conversion of the reaction directly).
The default factor is 2%, but it can be optimized by
studying the conductivity relation of each species with
the temperature and then adjusting the compensation
factor (between 0 and 5%) that better fits each reaction
1) To compensate for the compensation factor of the
Conductivity meter, press “TEMP”. The value adjusted
At that moment will appear in the screen. Press “TEMP”
Again to exit the screen.
2) To adjust the % of the compensation factor press“TEMP”
and then the key “FACTOR ADJ” successively until obtaining
the desired value (Between 0 and 5%). Press “TEMP” again
to exit.

16. Continue.. (CSTR)

17. Methodology:
1-dissolve 4 grams of NaOH in some distilled water .
2-fill a bottle of 800 ml of the NaOH mixture and
additional distilled water. And another bottle of water.
3-fix the bottles in their places and tide the pipes and
valves.
4-power on the Electronic Console and the heater to
increase the heat of the water in the bath and read the
first temperature reading and its conductivity.
5-open the pump and read the readings of temperature
and the conductivity for every 30 seconds.
6-after finishing readings for several times turn of the
pump and the Electronic Console then pour all the liquid
in the reactor.

18. Graphs:

19. Discussion:
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.
Salts, acids, and bases are electrolytes. They dissolve in water to form ions.
Although water is not an electrolyte, a very small concentration of
hydrogen and hydroxide ions are always present in pure water.
Increasing the temperature of an electrolyte solution always increases the
conductivity. The increase is significant, between 1.5 and 5.0% per °C. To
compensate for temperature changes, conductivity readings are commonly
corrected to the value at a reference temperature, typically 25°C. All
process conductivity sensors have integral temperature sensors that allow

20. Continue..
the analyzer to measure the process temperature and correct the raw
conductivity. Three temperature correction algorithms are in common use.
When we have to repeated conductivity measurement it means that there
is a mistake in increasing temperature so that and it proves that the ions
that conduct in the same temperature are equal in their conductivity
motion.
Position of conductivity cell
Make sure that all the poles of the conductivity cell are completely covered
by the sample. Always position a 2-pole cell in the center of the measuring
vessel.
Low conductivity measurements:
• use a flow-through cell, to avoid atmospheric contamination from carbon
dioxide,
• use cells with low cell constant, 1 cm-1 or lower,
• use non-platinized cells for easier cleaning and faster response,
• make sure that your instrument is able to apply an appropriate
measuring frequency
High conductivity measurements
• Use platinised cells to avoid polarisation errors, preferably 4-pole cells.
• Use cells with a high cell constant (1 cm-1) or higher if possible.

21. Continue..
• Do not dilute samples in order to bring them into measuring range.
Conductivity is not proportional to concentration at high levels.
• Make sure that your instrument is able to apply an appropriate measuring
frequency.
Since the accuracy of any measurement depends on proper calibration, a
fresh standard must always be used. Ideally, sample beakers and sensor
should be rinsed two to three times with the sample as the presence of
contaminants can lead to additional errors in conductivity results
When setting up a conductivity measurement system, the lab manager
must make appropriate choices relating to TC(temperature compensation),
such as o whether TC should be used, o setting the reference temperature,
o choosing a linear or nonlinear TC, and o choosing the appropriate TC
factor.

22. References:
1.http://www2.emersonprocess.com/siteadmincenter/
PM%20Rosemount%20Analytical%20Documents/Liq
_ADS_43-018.pdf
page 1
2.http://us.mt.com/dam/MT-
NA/pHCareCenter/Conductivity_Reduce_Common_E
rrors_WP.pdf
page 3
3.http://igz.ch/de/produkte/uebersicht.asp?action=do
wnload&fileid=8205
page 21
4.http://www.thermofisher.co.nz/Uploads/file/Environ
mental-Industrial/Environmental-Monitoring-
Safety/Water-Monitoring-Treatment/Tech-Tip-Top-
Ten-Conductivity-Mistakes-NZ.pdf
page 1