INSTRUMENTATION MANUAL
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TOPIC:
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UKS
ANALYTICAL INSTRUMENTS
1. Introduction to Analytical Parameters :The development and use of process analyzer for on stream applications has been a
contributing factor to the growth of the chemical, petrochemical and refining
industries in recent years. With proper design, installation and use, process
analyzers have proven to be invaluable by providing better quality products and
solutions to many process problems. The transition from laboratory use to process
analysis and control, however, has not been without difficulty. Early model analyzers
were merely
adaptations of laboratory
models , unsuitable for many of their
assigned tasks and often poorly engineered from their conception. While today’s
process analyzers perform capably and have been accepted by operating and
management personnel, an improperly engineered installation can still lead to
wastage of money, mistrust among operators and a maintenance headache.
Analyzer installations require a great amount of study and appraisal if they are to be
properly engineered. Some analyzer applications are straightforward and require
practically no research in order to determine what type analyzer should be used and
under what conditions they will operate. Mostly an investigative program must be
undertaken to determine the best analyzer system to be used as per process
conditions, state of the sample including it’s flow, temperature, pressure, viscosity,
stream composition and steam contamination such as solids, oils, and water.
This estimate, with savings data furnished by the process-engineering group, is used
to determine the economic feasibility. Many analyzers today are justified on the
basis of safety or pollution monitoring rather than economics.
Basically the analyzers can be grouped as per the state of the sample into two i.e.
Gas Analyzer & Liquid Analyzer.
Before going deep into the different analyzer systems we must have some brief idea
on the basic sampling system of the analyzers.
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Sample system: - The design of the sample system for an analyzer is equally as
important as the application of the analyzer itself. The sample system may vary in
complexity from a simple shutoff valve and single tubing connection to a complicated
system consisting of solenoid valves, filters, vaporizers, regulators and other items.
Basic principles of the sampling are as follows:
1. Extraction of a representation sample from the stream.
2. Cleaning the sample.
3. Minimizing the time lag in getting the sample to the analyzer.
4. Meeting the pressure, temperature and sample flow rate requirements of the
analyzer as well as the vaporizing a liquid sample or removing water drops.
5. Disposition of the sample in a safe area.
The application of these basic principles is discussed in the following paragraphs.
Sample location
The sample point must be in an active stream to assure that it provides the
information required by the analysis. Sample points on process lines should always
be installed on the top or side of the pipe, never on the bottom. This prevents the
flow of condensed liquids in vapor streams from entering the sample valve and also
eliminates the entrance of fine solids, which may be swept along the pipe. The side
tap is preferred on liquid streams to minimize the chances of getting entrained
vapors. The probe shown in below is commonly used to extract a sample from the
center of the stream; thereby avoiding condensed liquids in a vapor stream and
solids in a liquid stream. A clean stream is important to successful low maintenance
operation of most analyzers.
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Filters
It should be assumes that all sample streams contain solid contaminates such as
rust particles, polymers, etc; therefore, minimum requirements call for a fine mesh
wire filter. Extremely fine solids sometimes require the use of a porous metallic or
ceramic filter. The gaskets and diaphragms of all pressure regulators, flow
controllers, filters, etc., should be examined to determine that they will not
deteriorate or absorb components from the stream. The filter might be considered as
one of the most critical components in the sample conditioning system simply
because so many other functions are performed after the stream has been cleaned.
Some vapor samples contain so much entrained solids that filtration is not practical
until the vapor is scrubbed either by bubbler devices or by small spray scrubbers.
Sampling Time Lags
Sampling time lags delay the analysis and may reduce the usefulness of the
measurement. The analyzer needs to be located close to the sample point, but that
is not always feasible. A bypass loop such as that shown in the figure below is often
Sample Flowmeter
Analyzer
Bypass Rotameter
used to reduce time lags in long sample runs where the analyzer will handle only a
small flow rate. This system can be used on liquids or gases whenever there is a
point of lower pressure for sample return or when the sample can be vented or run
to a sewer. Installing it in raceway or thin-wall pipe should protect transport tubing.
The tube should be sloped downward toward the analyzer to drain liquids, and no
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INSTRUMENTATION MANUAL
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pockets should be left in the line without a condensate trap. Tube size is determined
by flow conditions. Flow volume should be as low as possible and velocity should be
as high as is practical to minimize lag time.
Sample Conditioning
An effort should be made to match the sample requirements of the analyzer to that
of the stream, there by minimizing extra system components such as vaporizers,
regulators, sample coolers, etc. If a liquid sample pressure is to be reduced , care
should be taken that flashing does not occur. However, it is not always possible to
match the analyzer to the process condition, and the sample must necessarily be
conditioned to meet the analyzer requirements.
The sample parameters like temperature, pressure, flow and etc. are very important
when the sample is processing in to the analyzer .
Temperature
Many manufacturers make small heat exchangers to cool the sample. Cooling water
may be allowed to flow unregulated through the exchanger, leaving the sample
temperature uncontrolled. Some Analyzers are temperature sensitive, however, and
the measurement can be improved by controlling the sample temperature. In some
cases, close temperature control is essential to the separation and measurement of
components.
Pressure
Pressure is also a common mismatch. Regulators are used to reduce high pressure
and to regulate varying low pressure. To prevent maintenance problems and
increase performance, the regulator should be preceded by a fine mesh strainer.
Materials should be noncorrosive.
Single stage regulation is usually sufficient for sample pressure reduction.
On vapor systems the regulator is usually located at the sample point to keep a high
sample velocity with a low flow rate. When the sample pressure increases then there
may require a relief valve or rupture disc for overpressure protection.
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Flow
Many analyzer are sensitive to velocity changes, and the sample flow rate must be
monitored / controlled. Where sample conditions are constant, a simple rotameter
suffices. When sample conditions are not constant, a rotameter ( constant
differential regulator combination ) should be used. The instrument manufacturer
recommends the flow rates of each instrument.
Sample Disposal
This is the last and most critical stage of the sampling system. Sample disposal
sometimes presents significant problems. Safety has always been a consideration
since many samples are either toxic or flammable or both. In some applications the
sample may simply be dumped or vented to the atmosphere. In others, where
venting becomes dangerous, other solutions are required.
Liquids
When disposing analyzed samples of water or other inexpensive, nonpolluting,
nonhazardous liquids, the most common method is to run it to the sewer and then to
the effluent plant. This method may also be used on hazardous or polluting samples
if an appropriate chemical sewer is located nearby. If sample is expensive or cannot
be conveniently run to the sewer, it is commonly returned to the process system at a
point where the pressure is lower than the sample pressure and as steady as
possible.
Vapors
Vapor samples present slightly different problems. Non-hazardous gases are
normally vented to the atmosphere while hazardous gases are often vented to a
flare header or returned to the system, whichever is more convenient. Gases, which
cannot be vented to a flare header or returned to the system, may be scrubbed of
the corrosive or toxic components and then vented to the atmosphere or flare
header.
Vent flow can be very critical to the successful performance of an analyzer.
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2. Type of Analyzers in Fertilizer Industries
In the Fertilizer field the most commonly used Analyzer can be grouped as below. This
will mostly cover all type of Analyzers are used in a Chemical Plant like us.
Type of Analyzers
2.1 Gas Analyzer
2.1A Process Gas
2.2 Liquid Analyzer
2.1B Flue Gas
2.1Ai S.G.Analyzer
2.2A BFW / Cooling Water/ Steam / Effluent pH
2.1Aii Gas mol % Analyzer
2.2B BFW / Steam Conductivity Analyzer
2.2C DM Water Silica Analyzer
2.2D Ammonia Analyzer
2.2E Dissolved O2 Analyzer
2.1Bi O2 Analyzer
2.1Bi a Paramagnetic Type
2.1Bii SOX Analyzer
2.1Biii NOX Analyzer
2.1Bi b Zirconium Type
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2.1Ai Specific Gravity Analyzer
Methodology
There are basically three type of methods for measuring of Specific Gravity
Analyzer.
1. Gas Density Detector
2. Gas Impulse Wheel Method
3.Metering Orifice Method
Gas Density Detector
A continuous type of measuring device , where a
continuous flow of known
Reference Gas as well as the Sample Gas are coming in contact with the two
thermistors or hot wires vertically located at Upper and Lower branch / arms , finally
wired to a Wheatstone Bridge , is balanced in exactly equal Density. If the Density of
the sample gas exceeds even slightly than that of Reference Gas, there will be a
Upper Branch
Sample Inlet
Gas Mixture
OUT
Reference Gas
IN
Lower Branch
Detector Element
tendency of Sinking of the Sample Gas into the Lower branch of the vertically
located fluid bridge. This obstructs the flow path, causing a rise in Temperature of
Lower Detector element and unbalancing the Wheatstone Bridge. So in the case of
lighter Sample Gas, the Upper Detector element causes a rise in Temperature due
to flow restriction of the Upper branch of the vertically located fluid bridge and
unbalancing the Wheatstone Bridge .
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Gas Impulse Wheel Method
In this method a continuous stream of gas sample is into the lower measuring into
the lower measuring chamber of the instrument by a gas impulse wheel and put in
whirling motion and driven against the blades of a companion impulse wheel located
in the same chamber . Both wheels exert a torque on each other , each trying to
rotate in an opposite direction . The result is net motion which depends on the
difference in torque between the two impulse wheels and which position the indicator
needle . As the difference between the opposing torque is a function of the specific
gravity of the gas , it is indicated by the indicator needle.
The impulse wheel in the air chamber is produced to compensate for changes in fan
speed , temperature , humidity , and atmospheric pressure . To achieve this , gas
sample and air are brought to the same temperature and humidity by passing them
through separate compartments in the same humidifier . Because of the high rate of
sampling and the small internal volume of the measuring chamber , response to the
gas density changes is almost instantaneous.
Metering Orifice Method:
In this method a continuous sample is drawn from the process by a constant volume
blower , through a pressure reducing valve which is set for constant volume blower,
through a pressure reducing valve which is set for a constant down stream pressure
of about 10cm of water column . In this way the variations in gas supply pressure are
smoothed out , which other wises would affect the gas sampling accuracy. The
sample is then passed through the metering orifice and then through a second
orifice to atmosphere . Between the two orifices plates the line is tapped by a
recycling line that connects back to the suction side of the blower . The atmospheric
discharge is thus limited to about 30% of blower capacity . The differential pressure
of the constant volume flow across the metering orifices varies with changes in the
specific gravity of the sample .
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Functional Operation
Here we are discussing the function of Solartron Make, Model NT3096 , which
measure on the Metering Orifice Method.
By definition ,
Molecular Weight of Gas
Gas Specific Gravity (G) =
MG
=
Molecular Weight of Standard Air
MA
Where MA is taken as 28.96469
The specific gravity transducer consists of a gas reference chamber, constructed
such that it surrounds a vibrating cylinder gas density transducer, thereby helping to
achieve good thermal equilibrium. The gas reference chamber has a fixed volume
which is initially pressurised with the sample gas. It is then sealed by closing the
reference chamber valve, thus retaining a fixed quantity of gas now known as the
reference gas.
The sample gas enters the instrument at the base plate and passes through a spiral
heat exchanger so that it enters the gas density transducer at the equilibrium
temperature. The gas then flows down to a pressure control valve chamber.
The reference gas pressure acts through a separator diaphragm on the pressure
control valve chamber so that the gas pressure on both sides of the diaphragm are
equal, i.e. the gas pressures within the gas density transducer and the reference
chamber are equal.
As the ambient temperature changes, the pressure of the fixed volume of reference
gas will change as defined by the Gas Laws. This change in pressure will affect the
sample gas pressure within the density transducer such that the temperature and
pressure changes are self-compensatory.
If the sample gas pressure rises above that of the reference chamber pressure, the
pressure control valve opens to vent the excess gas via the outlet connection in the
base plate. In this manner the sample gas is made equal to the reference gas
pressure. For gas to flow it is necessary that the supply pressure than the reference
pressure which in turn must be greater than the vent pressure.
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Thermal
Insulation
Density
Transducer
To site
Electronics
Ref Chamber
Valve
Diaphragm
Temp
Stabilizer
PRV
Orifice
PCV
Filter
Control
Pressure
Indicator
C
Outlet
A
Sample
Gas Input
B
Calibration Gas Input
NT 3096 Type Specific Gravity Measuring System
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A pressure gauge is fitted so that the gas pressure within the gas density transducer
can be monitored. This is desirable when charging the reference chamber and
general maintenance use.
A thermal insulation cover is placed over the complete instrument so that rapid
changes in ambient temperature will not upset the temperature equilibrium of the
control assembly. The electrical connections to the transducer are taken to a
terminal box located on the bottom surface of the base plate.
Transducer Sensing Element
The gas density transducer consists of a thin metal cylinder, which is activated so
that it vibrates in a hoop mode at its natural frequency. The gas is passed over the
inner and outer surface of the cylinder and is thus in contact with the vibrating walls.
The mass of gas, which vibrates with the cylinder depends upon the gas density
and, since increasing the vibrating mass decreases the natural frequency of
vibration, the gas density for any particular frequency of vibration can be determined.
A solid state amplifier, magnetically coupled to the sensing element, maintains the
conditions of vibration and also provides the output signal. The amplifier and signal
output circuits are encapsulated in epoxy resin.
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2.1Aii Gas mol % Analyzer
Thermal conductivity Type
If a cylinder has a heated wire placed along its axis and the cylinder is filled with gas,
the wire will lose heat to the surrounding walls by conduction, convection and
radiation.
The motion of the gas molecules is random and their average energy is proportional
to the gas temperature. if some of these molecules collide with the hot wire, they will
acquire an increase in energy, some or all of which may be lost if they subsequently
collide with the cylinder walls.
The amount of heat lost to the cylinder walls is a measure of thermal conductivity of
the gas , depending
on the number of molecules and their velocity
and is
determined by the gas pressure , density and mean temperature.
Measurement of thermal conductivity
Measurement of thermal conductivity of a pure gas ‘sample’ is relatively simple if
the sample pressure is controlled , because the conductivity can then be compared
against a “standard”.
The behavior of a mixture of gases is not entirely predictable with respect to their
total
conductivity. The conductivity curves of many mixtures have been plotted
experimentally but a standard is still required for use with the curves.
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Typical thermal conductivity cell
The temperature of the wire in the cylinder is determined by the balance between
the electrical heat energy supplied and the heat energy removed by the gas. The
resistance of the wire is proportional to temperature and this resistance forms one
arm of the Whetstone bridge.
The wire through a similar cylinder containing a
standard gas is used as another arm of the bridge.
Only a small fraction of the total flow passes over the heated wire.
Heated Wires
Vent
Flow Regulator
Sample Gas
Reference Gas
The katharometer
The katharometer , another name of the Thermal Conductivity Detector, differs from
other cells in that it is independent of sample flow rate. The only contact the wire has
with the sample is by gas diffusion through the glass capillary surrounding the hot
wire. As the wire is heated electrically so one of the arms of a wheatstone brdge
and as well as the thermal conductivity of the gas surrounding changes it’s
temperature and resistance. These changes in resistance are converted into output
voltage changes by the wheatstone bridge. This simple device is capable of
detacting changes in the composition of a gas such as hydrogen or nitrogen in the
order of 1 part per million.
The katharometer employs a bridge circuit comprising two standard cells
and two measuring cells, thus doubling the sensitivity.
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Simple Bridge system for determining Thermal Conductivity
The two cells are hold vertically in a highly thermally conductive metal, so that their
case temperature are the same and only their platinum resistance wires vary in
temperature. The reference ( or standard cell ) is sealed, but the measuring cell is
open to the sample gas. The pressure, inlet temperature and flow of the sample gas
are usually controlled.
Measuring Cell
Reference Cell
Thermal conductivity CO2 analyzer
Although most commonly used as a CO2 analyzer for flue gas analysis this
equipment could be used for any gas with a marked difference in thermal
conductivity to that of reference gas. The reference gas would normally be same as
the gas of the sample point but without having any of the gas being deleted in it.
The two gas flows are drawn through the equipment by an aspirator at regulated
flow rates. They first pass through a cooler to reduce the temperature (if necessary)
of the sample and to ensure that both sample and reference are at the same
temperature. Then the gases pass through humidifiers to ensure that they are both
equally saturated. After passing through the rotameter the gases enter their
respective detector blocks where their thermal conductivity are compared by four
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active elements. One piece of detector block ensures that the wall temperatures of
the enclosures are same. Gas diffuses rather than flows into the chambers
containing the detectors so that the actual flow over the wires is kept to a minimum.
The two regulators maintain constant equal flow and keep side effects due to flow
and pressure changes to a minimum.
TO ASPIRATOR
FLOW REGULATOR
FLOW REGULATOR
DETECTORS
ROTAMETER
COOLER
SAMPLE
REFERENCE
HUMIDIFIERS
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2.1Bi a Paramagnetic Type
The physical property which distinguishes oxygen from most other common gases is
it’s Paramagnetism. The only common gases having comparable Paramagnetic
susceptibility are NO, NO2, and ClO2 .
paramagnetic oxygen analyzer
Faraday showed that all substances are affected by magnetic fields – those
attracted into strong magnetic fields called Paramagnetic and those forced out of
strong field called Diamagnetic. Some substances become magnetized in the
opposite direction to an applied magnetic field and are therefore attracted in to
magnetic field ( Paramagnetic ). Some materials are strongly paramagnetic and
because of their magnetic similarity to iron are called Ferromagnetic materials.
Most gases are diamagnetic (i.e they tends to move away from the most intense part
of a magnetic field ) Oxygen
is distinguished
by being relatively strongly
paramagnetic ( i.e. it is attracted by a magnetic field ). This difference makes it
possible to analyze Oxygen by magnetic methods. The relative magnetic
susceptibilities of a number of gases are given in the table below, normalized to a
scale on which nitrogen = 0,
GAS
Oxygen = 100 .
Percent relative susceptibility
Nitrogen
0
Oxygen
100
Ammonia
-0.26
Carbon dioxide
-0.27
Carbon monoxide
+0.01
Hydrogen
+0.24
Methane
-0.20
Nitric oxide
+43.0
From the table it can be seen that oxygen cannot be analyzed in the presence of
nitric oxide by this method.
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Magnetic Wind O2 Analyzer
This instrument relies for its operation on the fact that oxygen becomes less
paramagnetic with rise in temperature. The sample gas passes round a chamber
and diffuses into the bypass pipe across its center. The heaters raise the
temperature of the gas on the by pass pipe and if there is any oxygen present, its
paramagnetism is reduced. Cool oxygen is drawn in to the bypass tube by the
powerful magnet because it is more paramagnetic than the heated oxygen. The flow
of gas thus created through the bypass tube causes the left hand heater to be cooler
than the right hand and therefore for lower resistance. This puts the whetstone
bridge supplying the current out of balance and generates an out of balance voltage
that can be measured on a conventional mV ( V0 ) indicator.
V0
Magnet
Pole
VI
An increase in ambient temperature reduces the indication by about 1.5% C. This
can be offset electronically using a resistance thermometer or by using a
temperature controlled housing. The temperature of sample gas should not exceed
75 C and its pressure should be between 1 p.s.i. of the pressure at which the
instrument has been calibrated. The other gases in the sample must be able to
withstand 250
without degrading. Ranges between 0 to 3% and 0 to 25% are
typical.
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2.1Bi b Zirconium Type
Principle of Operation
The solid electrolyte (zirconium porcelain) exhibits conductivity to oxygen ions at
high temperatures. Accordingly, if a zirconia element with platinum electrodes on the
internal and external surface is heated and gases with different oxygen partial
pressures are allowed to contact the surfaces, the zirconia element will exhibit the
properties of an oxygen concentration cell.
More specifically , oxygen molecules turn into
oxygen ions with the addition of
electrons at the electrode (cathode) with a higher oxygen partial pressure. The
oxygen ions then move through the solid electrolyte to the anode where they release
electrons and thus turn back into oxygen molcules.
Cathode : O2 + 4e ------------ 2O2
Anode:
2O2 --------------- O2 + 4
Electromotive force E(emf) mV developed across the two electrodes through this
reaction is obtained by Nernst ‘s formula as follows:
E = - (RT/Nf )ln (PX/PA)
Where ,
R = Gas constant
T = Absolute Temperature
N=4
F = Farady constant
PX = Oxygen concentration (%) on comparison air for zirconia element
PA = Oxygen concentration (%) on comparison air for
zirconia element – normally 20.95% O2.
If the cell set temperature is 750 ºC , the above formula is transformed as follows:
E = - 50.74 log (PX/PA)
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Heater Power Supply
4 ~ 20mA O/P
Cell Output ,
20.6% O2
T/C ,
Output , Ref.Junction
Contact O/P
Ejector
Power Supply
Stop Valve
Air Supply
/ Zero Span Gas
This analyzer heats the zirconia element to a specified temperature. The
measurement gas then flows on side of the element and the reference air flows on
the opposite side . Consequently , an emf proportionally to the ratio of oxygen
concentration in the measurement gas to the oxygen concentration in the reference
air is developed , which enables the oxygen concentration in the reference
measurement gas to be measured .
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2.1Bii SOX Analyzer
The ultraviolet analyzer is designed to determine continuously the concentration of
SO2 in a flowing gaseous mixture. The analyzer is capable of measurement in the
50 to 5000 ppm range. Here we discussed about the UV SO 2 Analyzer Rosemount
Make, Model 890.
Operational Principal
The model 890 employs a pulsed UV lamp with peak wavelength generation from
225 to 650 nanometers. The pulsed lamp eliminates the requirement for a
mechanical chopper and the attendant noise and stability problem. The ultraviolet
source emits a pulsed (30Hz) beam of energy. This energy is split by a beam
splitter, each beam being directed to pairs of detectors before and after the sample
cell.
One of the unique features of the model 890 is the use of spectrally selective,
“Transflectance”, mirrors. These mirrors isolate the sample and reference spectral
passbands for the detectors. They reflect energy below a wavelength region and
transmit the remaining, higher wavelengths, all with much lower energy loss than the
more commonly used bandpass interference filters.
This measurement bench provides a number of unique advantages over
conventional ultraviolet photometers. Increased radiation transmission at the
measurement, reference and interferent compensation wavelengths provides 4 to 5
times the energy transmitted in conventional benches employing optical filters. This
increase yields an extremely stable, sensitive and drift-free analysis.
Four detectors are used in this system, two before the sample cell ( sample before
[ Sb ] and reference before [ Rb ] ) and two after ( sample after [ Sa ] and reference
after [ Ra ] ) .
Sb and Sa receive energy in the 265 to 310 nm wavelength region, Rb and Ra in the
310 to 355 nm region.
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These four detectors measure SO2 concentration and correct for NO2 interference
and UV lamp fluctuations. The difference between detector determinations is the
SO2 concentration, following this formula :
SO2 = [ f (Rb) – Sb ] - [ f (Ra) – Sa ]
The sample gas is introduced to the sample cell, and the component of interest
absorbs ultraviolet energy in proportion to the concentration in the gas. This
difference between the signals of the detectors located at both ends of the sample
cell determines the concentration of SO2 in the sample.
Working Principal ( Optical Bench )
A collimating mirror is used to focus and direct the pulsed UV energy. Just prior to
entering the sample cell, a planner, non-position-sensitive beam splitter is utilized to
direct 50% of the transmitted energy to the first detector block assembly.
In the detector block, transflective mirrors with selective wavelength reflection
characteristics are used instead of optical filters. Theses mirrors further isolate the
radiation into the required measurement and reference wavelengths, and reflect it
onto a set of matched silicon photodiode detector assemblies.
A second detector block located just after the sample cell is an exact duplicate of the
first. This dual detector array allows the signal processing circuitry to yield a highly
sensitive and accurate SO2 analysis.
Additionally, utilizing this same technique on a second set of adjacent wavelengths
allows accurate measurement and elimination of the effects of absorption by
interferent gas or gases such as nitrogen dioxide.
Coupled with the four-detector , multiple wavelength analysis technique described
above, a unique detector output signal integration and de-integration signal
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DETECTOR
DETECTOR
Sb
Ra
Transflectance
Mirrors
Sa
Beam Splitter
Sample Cell
Transflectance
Mirrors
U V Lamp
Model 890 Optical bench
processing scheme allows a continuous on-line correction of dark current and
electronic noise errors. This effectively resets the electronic zero every 30
milliseconds, and yields a measurement which is virtually free of instability and drift.
Additionally, the adjacent ( non - SO2 - absorbing) reference wavelengths are used
as a baseline for measurement and correction of sample interferent components,
particularly NO2 .
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2.1Biii NOX Analyzer
Overview
The NOX analyzer continuously analyzes a flowing gas sample for NO X  nitric oxide (
NO ) plus nitrogen dioxide (NO2 ) . The sum of the concentrations is continuously
reported as NOX.
The analyzer is based on the chemiluminescence method of NO detection. The
sample is continuously passed through a heated bed of vitreous carbon, in which
NO2 is reduced to NO. Any NO initially present in the sample passes through the
converter unchanged, and any NO2 is converted to an approximately equivalent (
95%) amount of NO.
. The analyzer is capable of measurement in the 50 to 5000 ppm range. Here we
discussed about the UV SO2 Analyzer the NO is quantitatively converted to NO2 by
gas-phase oxidation with molecular ozone produced within the analyzer from air
supplied by an external cylinder. During this reaction, approximately 10% of the NO2
molecules are elevated to an electronically excited state, followed by immediate
decay to the non-excited state, accompanied by emission of photons. These photons
are detected by a photo multiplier tube, which in turn generates a DC current
proportional to the concentration of NOX in the sample stream. The current is then
amplified and used to drive a front panel display and to provide potentiometric and
isolated current outputs.
To minimize system response time, an internal sample by-pass feature provides
high-velocity sample flow through the analyzer.
The analyzer is capable of measurement in the 10 to 2500 ppm range. Here we
discussed about the UV NO2 Analyzer Rosemount Make, Model 951C.
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Operational Principal
The chemiluminescence method for detection of nitric oxide ( NO ) is based on its
reaction with ozone ( O3 ) to produce nitrogen dioxide ( NO2 ) and oxygen ( O2 ).
Some of the NO2 molecules thus produced are initially in an electronically excited
state ( NO2* ). These revert immediately to the ground state, with emission of
photons ( essentially red light ). The reactions involved are:
NO + O3
NO2* + O2
NO2*
NO2
+ Red Light
As NO and O3 mix in the reaction chamber, the intensity of the emitted red light is
proportional to the concentration of NO .
( Any NO2 initially present in the sample is reduced to NO by a heated bed of
vitreous carbon through which the sample is passed before being routed to the
reaction chamber.)
The intensity of the emitted red light is measured by a photo multiplier tube ( PMT ) ,
which produces a current of approximately 3 X 10‾9 amperes per part- per-million of
NO in the reaction chamber.
Ozone Generation
Suitably pressurized air from an external cylinder is supplied to the rear panel AIR
inlet. The proper pressure setting is 20 to 25 psig. Within the ozone generator, a
portion of the oxygen in the air is converted to ozone by exposure to an ultraviolet
lamp. The reaction is:
3O2 UV
2O3
From the generator, the Ozonized air flows into the reaction chamber for use in the
chemiluminescence reaction.
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Signal Processing in Electronics System
A block diagram of the Analyzer signal-processing electronics is shown in the figure
below:
SIGNAL / CONTROL PC BOARD
Photomultiplier Tube
PMT
Programmable
Amplifier Gain Amplifier
Span
Amplifier
DISPLAY
Potentiometric
Output
Zero Control
Range Switch
Span Control
Isolated
Current Output
High Voltage Supply
Voltage-to-Current Converter
PART OF POWER SUPPLY PC BOARD
Basic functions of these electronics are acceptance of PMT output and conversion of
it to potentiometric and isolated current outputs, and providing a visual display of the
concentration of the NOX in the sample stream. All function except the high-voltage
source and the voltage-to-current converter are contained on the Signal Control PC
board.
The PMT drives a high input impedance amplifier which produces a voltage between
0 and approximately 5 volts. The zero control injects a small current into PMT
amplifier to null any current from the PMT. The gain of the programmable gain
amplifier ( PGA ) is controlled by the range switch as well as the Span Control switch.
The Analyzer has a thermal system to provide a stable Thermal environment for the
PMT.
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2.2A BFW / Cooling Water/ Steam / Effluent pH Analyzer
What is pH Value?
pH, term indicating the hydrogen ion (positively charged hydrogen atom)
concentration of a solution, a measure of the solution’s acidity. Hydrogen ions are
usually represented by the symbol H+. The term (from French pouvoir hydrogène,
“hydrogen power”) is defined as the negative logarithm of the concentration of H +
ions: pH = -log10[H+], where [H+] is the concentration of H+ ions in moles per liter .
Because H+ ions associate with water molecules to form hydronium (H3O+) ions ,
pH also is often expressed in terms of the concentration of hydronium ions.
In pure water at 22° C (72° F), H3O+ and hydroxyl (OH-) ions exist in equal
quantities; the concentration of each is 1 x 10 -7 moles/liter, creating a neutral
solution. Consequently, the pH of pure water is –log (1 x 10-7), which equals log (1 x
107), or 7. If acid is added to water, however, an excess of H 3O+ ions is formed: H+
(acid) plus H2O (water) yields H3O+ (hydronium ions). When the concentration of
H3O+ exceeds the concentration of OH-, the solution becomes acidic. In an acidic
solution, the concentration of hydronium (H3O+) ions can range from 1 to 1 x 10-7
moles/liter (but not including 1 x 10-7), depending on the strength and amount of the
acid. Therefore, acid solutions have a pH ranging from 0 up to, but not including, 7.
Acids with lower numbers are stronger. Inversely, when the concentration of OHexceeds the concentration of H3O+, the solution becomes basic. In a basic solution,
the concentration of hydroxyl (OH-) ions can range from 1 to 1 x 10-7 moles/liter (but
not including 1 x 10-7). This corresponds to a concentration of hydronium ions that
ranges from 1 x 10-14 to (but not including) 1 x 10-7 moles/liter. Therefore, basic
solutions can have a pH ranging from 14 down to, but not including, 7. Bases with
higher numbers are stronger.
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The pH of a solution can be measured by titration, which consists of the
neutralization of the acid (or base) by a measured quantity of base (or acid) of
known concentration, in the presence of an indicator (a compound the color of which
depends on the pH). The pH of a solution can also be determined directly by
measuring the electric potential arising at special electrodes immersed in the
solution .
Working Principle
The most common industrial method of measuring pH is by glass-cell and calomelcell electrodes used with a potentiometer instrument. In brief, this method requires
that an electrode be immersed in the solution. An electric potential is produced at the
electrode which forms an electrolytic half-cell. This is the measuring cell. A second
electrode is required to provide a standard potential and to complete the cell. This is
the reference cell. The algebraic sum of the potentials of the two half-cells is
proportional to the concentration of hydrogen ions in the solution.
Glass Electrode
The glass electrode is the measuring electrode in common use; it is shown in the
figure below:
Electrode Lead
Glass Envelope
Buffer Solution
Platinum Wire
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The glass electrode operates on the principle that a potential is observed between
two solutions of different hydrogen-ion concentration when they are separated by a
thin glass wall. This potential is a function of the two concentrations. A buffer
solution is contained in the permanently sealed glass electrode, which is surrounded
by the solution whose pH is being measured. The buffer solution in the electrode has
a constant hydrogen-ion concentration. The potential at the electrode therefore
depends on the hydrogen-ion concentration of the measured solution.
Reference Electrode
The calomel electrode is the reference electrode in common use; it is shown in the
figure below:
Electrode Lead
Glass Envelope
KCl Solution
Hg + HgCl Solution
Ground-Glass Joint for
Liquid Junction
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The calomel electrode is in common use as a reference electrode. The calomel (
mercury and mercurous chloride ) is contained in the inner tube and covers a
platinum wire. The potassium chloride, a saturated solution, is in liquid contact with
the measured solution, which surrounds the reference electrode. The liquid junction
is provided by a small hole in the electrode, over which a ground-glass cap is
placed, the junction to the outside provided by the liquid film in the glass joint. The
potential at the reference electrode is constant.
Cell Potential Measurement
The cell potential is measured by means of a potentiometer type instrument
operated from an amplifier connected to both electrodes. The amplifier is required
because the cell potential is very small and because practically no current through
the cell can be allowed.
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2.2B BFW / Steam Conductivity Analyzer
The measurement of conductivity
Ohms law :
For a circuit element Ohms law states that I = V / R where V is the
potential
difference in volts applied across resistor of resistance R in ohms to produce a
current I in amperes.
It is sometimes thought more convenient to write Ohms law as I = GV where G is
the conductance (or conductivity ) in Siemens and G= I / R.
Older texts refer to a siemens as Mho . Although applying equally as well as to
liquids and solids for all the applications that follow it will be the conductivity of a
liquid that is being measured .
Specific conductivity :
The conductivity of a liquid may be used to in for the amount of impurities that it
contains .The conductivity of a particular sample depends on its size & shape .To
make comparisons meaningful meters are designed to measure specific conductivity
, K, where K is the conductivity of a cube of fluid each edge of which measures 1
cm.
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Cell Constant :
The conductivity cell simply consists of two metal electrodes which will not corrode
such as gold coated with platinum black, A voltage is applied to the cell and current
is measured to find its conductance . The conductance depends upon the area , A ,
of the electrodes , their distance apart ,d , and the specific conductivity of the fluid ,
K , according to the formula
G=KA/d
Since G is measured but K is indicated the scaling of the instrument uses the
formula in the form
K= G d / A
Where d / A is called cell constant.
In a commercial cell k is impractical to find the cell constant by measuring A & d.
The cell constant is determined using a standard fluid of known conductivity . The
resistance of the cell can easily be measured over a range of 10 to 10,000 ohms but
the conductivity’s vary over a much wider range than this so that it is necessary to
have a cell constant from 0.1 to 100 .
Polarization error :
If a dc current is used in the measurement of conductivity the electrodes acquire
local emf’s due to electrolysis which tends to reduce the current and the apparent
conductivity . AC is the current used in measuring circuits to reduce the effects due
to polarization . The higher the frequency and the larger the electrode area the less
the polarization error. 1000 c/s is a suitable frequency ; above this value defects
arise from stray capacitance in the leads , etc.
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Installation of conductivity analyzer
Being generally mode of glass the cells are fragile and should be protected from
buffering by pulsating flow or suspended solids .
The holes in the glass cover should face the flow to ensure proper circulation and no
air should be trapped in the cell .
The electrodes should be periodically inspected for cleanliness and if they are not
protected by a glass shield they must be inspected for shape and position as
changes affect the cell constant.
When installed downstream of conductivity correcting influent to the main stream
sufficient space for adequate mixing must be allowed but at the same time the cells
must be so far down stream as to introduce so large a distance velocity log that
control becomes impossible .
The cell should not be allowed to dry out as if the pipe is not always full the cell
should be fitted pointing upwards at the bottom of U bend.
The maximum permissible temperature is typically 100 C and the maximum
pressure depends upon the seals used for the glass but say 40 psi . Consequently
for many applications it is necessary to transport a cooled sample at the low
pressure .
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Applications of conductivity analysis :
Boiler Feed water ( BFW ) :
Normal tap water contains dissolved salts that have to be removed before water can
be boiled to provide steam for turbines , etc. , other wise the salts would be
deposited on the surface of the heat exchangers or turbine blades , impairing their
efficiency . In such very dilute solutions all the impurities are ionized and the
conductivity is linearly proportional to the proportion of dissolved solid. It is possible
to measure as little as 0.1 ppm of impurity . If, as in marine applications , sea water
is used for cooling then the slightest leaks of salt water into the boiler water may be
detected by the conductivity analyzer.
Washing water :
Continued washing of a product with fresh water after it is clean , washes both lime
and water and places as necessary load on the effluent treatment plant .
Comparison of wash water conductivity before and after a washing operation will
indicate when the washing is complete.
Acid manufacture :
In the manufacture of sulphuric acid the optimum conditions require an acid strength
in the process of 98.5 % . This can be controlled by a conductivity analyzer.
Trace gas detection :
Atmospheric impurity at a very low level can be detected by bubbling the air in the
water and measuring its change in conductivity.
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Conductivity cell :
The cell shown are Bishop cells and are just one of a number of types available.
The two electrodes are insulated by glass and surrounded by a glass tube which
helps to isolate the cell from the effect of conductive paths around it such as the pipe
walls . The cell constant of the measuring cell can be adjusted in use by moving the
position of tapered plug . The
reference cell may be used for temperature
compensation where required .
Glass
Holes
REFERENCE CELL
MEASURING CELL
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Potential difference method :
W1 applies a voltage to the cell and the current that flows cause a P.D. across the
resistor SR. The amplifier drives the slider along the slide wire S until it finds the
same P.D. on S . The drive motor then stops as there is no input to the amplifier .
W2 provides volts for the slide wire . T he actual voltage across it being set by the
span resistor . W3 , RT , and its associated bridge supplies a small series voltage
that varies with temperature and adjusts the range of measuring slide wire .This
refers the indication of conductivity to a reference temperature .Rc is set for the
temperature coefficient of the liquid under test .
When the conductivity changes the out of balance voltage drives the slider to
rebalance the bridge . The conductivity scale is marked out along the length of the
slide wire . The reference cell contains a fluid with the same temperature coefficient
as the fluid with under test so both the lower arms of the bridge are equally altered
by temperature changes and there is no change in reading . If the true conductivity
at process condition is required the reference cell is replaced by a resistor.
SPAN
S
P
A
N
W1
W
2
SR
W3
M
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2.2C DM Water Silica Analyzer
Here we discussed about the Silica Analyzer HACH Make , Model 60000 used in
our DM water plant.
silica analyzer
The series 5000 Silica analyzer is a continuous reading , wet – chemical ,
colorimetric analyzer for determining silica concentration in water . It has automatic
decimal point positioning to provide optimum resolution over the total analysis range
of 0 to 5,000 micrograms per litre ( µg/L or ppb) silica (SiO2) . Chemical analysis
utilizes the Heteropoly blue method (also called molybdenum method ) adapted
from Standard Methods for the examination of Water and Wastewater.
Method of analysis :
The Heteropoly blue method is used to measure molybdate –reactive silica.
Molybdate 3 Reagent , an acidic molybdate solution , is added to the sample to react
with any silica and phosphate present to form molybdosilicic and molybdophosphoric
acids.
Then , citric acid
/ surfactant reagent is added .Citric acid masks any
molybdophosphoric acid present and reacts with excess molybdate . This prevents
molybdate from producing an interfering blue – colored compound. The surfactant ,
a wetting agent , minimizes air bubble
absorbance through
formation on the sample walls . Light
this solution is measured to determine a sample blank
reference absorbance . Color formed at this point is identical to the final color of a 0
µg/L silica sample . This provides a zero reference and compensates for any
background turbidity and color inherent in the sample , change colorimetric lamp
output or contamination of the sample –cell walls.
Amino acid F reagent is added to reduce molybdosilicic acid to a blue – colored
solution .The amount of color formed is directly proportional to the silica
concentration of the sample . Light absorbance through the solution is measured at
810 nm . This absrobance , and the silica concentration is calculated .
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Principle of operation :
Operation series 5000 silica analyzer is semi continuous where discrete portions of
sample are captured and analyzed in a time sequence .When an analysis is
complete , new sample flow purges the sample cell , and the analysis cycle repeats
automatically .If the sample is maintained at inlet temperature of 30 to 50 deg C by
normal user or by a sample heater , set the measurement cycle time to 8.8 minutes
to take advantage of the faster reaction time at this temperature. Otherwise , when
the sample temperature is in the range of 5 to 40°C, set the measurement cycle time
to 15 minutes to ensure adequate reagent / sample reaction times.
Sample In
Drain Block
External Pr.
Regulator
Sample
Pressure Sensor
Sample Valve 1
2
3
4
5
Pr. Relif
Exhaust
Reagent Pr.
Manifold
Reagent Take-Up Tubing
Sensor
1
2
3
4
Amino
Acid F
Reagent
Citric
Acid /
Surfactant
Reagent
Molybo
ate 3
Reagent
Silica
Standar
d
FLOW DIAGRAM
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A constant flow is directed through 2 way valve to the sample cell. To keep fresh
sample available to the analyzer on a continual basis , a sample pressure
conditioning kit is provided with an adjustable needle valve for by pass flow
eliminating dead legs. A sample inlet pressure of 5+/- 3 psig (100 to 300 mL /min ) is
required to ensure adequate flow . At the beginning of each measurement cycle ,
incoming sample flows is directed to the sample cell. The sample is cell filled 10
times. The excess sample flows through an overflow weir to drain . A precise sample
volume is maintained by the overflow weir. Reagents are stored in containers
pressurized at a nominal 12+/-3 psig. By monitoring reagent pressure and
temperature , the analyzer can dispense reagents accurately by timing the opening
of the solenoid valves. Once the sample cell has been filled , reagents are added in
the sequence .
A magnetic stirring motor is activated after reagents are added to ensure good
mixing . It is turned off to allow sample to stabilize and air bubbles to rise before
taking color measurements .
During a calibration cycle , standard solution stored in a reagent bottle is added to
sample cell in place of normal sample.
exactly as
The standard solution is analyzed ,
sample would be , and the result is used to calculate the slope of
calibration curve. This slope factor is used in all future measurements to calculate
sample concentration as shown in the following formula:
SiO2 = Slope X log(Reference /Sample)
Analysis module:
The analysis module contains the solenoid valves controlling sample and reagent
flow and the colorimetric measuring system. A sample measurement cell is placed
between a light source and a photodetector and filtered to measure light 810 nm .
Sample and reagents enter the cell through fittings in the cell cover , which prevents
external contamination . A magnetic stirrer is activated during reagent additions to
mix sample and reagents thoroughly .
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2.2D Ammonia Analyzer
ANALYSIS : AMMONIA
RANGE : 0.5 ~ 10 ppm N
SAMPLE : PROCESS WATER
Principle
The automated procedure for the determination of ammonia is based on the
modified Berthelot reaction; ammonia is chlorinated to monochloramine which reacts
with salicylate to 5-aminosalicylate. After oxidation and oxidative coupling a green
colored complex is formed. The absorption of the formed complex is measured
photometrically at 660 nm.
Here we are discussing the On-line Ammonia Analyzer ,SKALAR Make, Model
SA9000. The Analyzer is working on the principle of above Photochlorametrically.
Working Principle
Automatic segmented flow analysis is a method of chemical analysis in which a
stream of reagent and samples are pump through a manifold where the stream is
segmented with air bubbles. The segmented stream then enters the chemistry
module where it is treated, examples of treatments are mixing, heating, dialysis etc.
After treatment the stream enters a flow cell to be detected.
The air segmentation is used to eliminate cross contamination and to provide an
aliquot to mix different reagents.
Sample
Chemical
Treatment
Detection
Data
Handling
Reagent
The Principle of Segmented Flow Analysis
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Line Diagrams & Reagent Details
0.42 ml /min
Waste
Orange / Orange
Sodium
Dichlorolsocyanurate
40°C
Reactor
Flow Cell
10 mm
Filter
660nm
6401
5522
0.32 ml /min
Black / Black
Sodium
Nitroprusside
5246
0.23 ml /min
5201
Orange / White
5246
0.32 ml /min
Sodium
Salicylate
Black / Black
Sample / High st.
5246
0.16 ml /min
/ Low st.
Orange / Yellow
Air
0.23 ml /min
Orange / White
Buffer
Solution
1.20 ml /min
Yellow / Yellow
9245
5325
5201
5325
5201
Sodium Salicylate
Required Chemicals: Sodium Hydroxide
Sodium Salicylate
NaOH
C7H5NaO3
Distilled Water
Sodium Nitroprusside
Required Chemicals: Sodium Nitroprusside Na2 [ Fe ( CN )5 NO ]. 2H2O
Distilled Water
Sodium Dichloroisocyanurate
Required Chemicals: Sodium Dichloroisocyanurate C3N3O3Cl2Na. 2H2O
Distilled Water
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Overview of the Process Analysis
This on-line process analysis is divided into three parts:
1. Sampling, sample transport and sample pre-treatment
2. Analysis and measurement
3. Data acquisition.
  
Sampling Pump
Reservoir
Sample
TOC Monitor
Pre-treatment
SA 9000
Data Acquisition
Computer
Printer
Filter
This three parts involve the following:
1. Preconditioning of the sample may involve filtration, cooling to ambient, dilution,
pressure regulation, transport to the analyzer system and multi point sample
selection.
2. For the analysis system, reliability, response time, reproducibility, calibration and
user friendliness are amongst the most important factors.
3. Analytical data may be presented in different ways, a visual display on the
instrument showing the present status of the instrument and the measured value,
an analog output , RS232C for connection to printers and/ or host computers with
alarms for feedback.
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2.2E Dissolved O2 Analyzer
Elements of dissolved oxygen analyzer
Application :
The measuring equipment is mainly employed for oxygen measurement and
supervision of various points in the water system of steam boilers. It is however
equally suitable for oxygen measurements in heavy water of nuclear reactors.
Principle of operation :
The measuring principle is based on the characteristic of the lead type metal
,Thallium i.e It is only corroded by water if the water contains dissolved oxygen. The
product of this reaction ,Thallium oxide ,Combines with water to form Thallium
hydroxide which is well water soluble and is a very strong electrolyte. By allowing
water with dissolved Oxygen to pass through a Cartridge containing Thallium fillings
the electrical Conductivity of water Increases .The conductivity increase is a
measure of Oxygen content.
The Schematic arrangement of the measuring equipment ,comprising an analyzer
and a measuring unit is shown. The main components of the analyzer and the
thallium reactor (7) consisting of a cartridge filled with thallium filings and the
connected conductivity measuring cell (8) .Up-stream of the Thallium reactor an ion
exchanger cartridge (4) is provided which reduces the conductivity of the sample to
between 0.01 and 0.1 micro mho/cm .(In the case of heavy water to 0.001 micro
mho /Cm ) and keeps it practically constant.
The low remaining water conductivity can be measured by means of the conductivity
cell
(5) and can be deducted electrically from the conductivity value measured
behind the Thallium reactor by means of a potentiometer graduated in Mho/Cm
.Thus only the conductivity of the water down stream of thallium reactor is evaluated
as the measured value for the Dissolved oxygen. On the inflow side o\f the analyzer
, a further conductivity meter (3) is provided by means of which the electrical
conductivity of the incoming sample water stream can be measured. In the case of
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Boiler feed water with the hydrazine addition it is advisable to connect a cation
exchanger in front of the analyzer.
SAMPLE INLET
1. Solenoid Valve
1
2. Sieve
3. Conductivity Meter
4. Ion Exchanger Cartridge
Bypass
2
5. Conductivity Cell
6. Conductivity Cell
7. Thallium Reactor
3
8. Conductivity Measuring Cell
9.
Flow Controllor
10. Flow Indicator
10
4
9
8
7
5
To stop the sediments and dirt , a sieve (2) is connected in front of the conductivity
cell (3) and to protect the ion exchanger filling as well as plastic pipe against too
high temperatures , a temperature monitor is provided in the inflow pipe , consisting
of solenoid vale (1) with bimetallic release.
In the measuring branch a flow controller (9) and a flow indicator (11) are further
more built in. The water flow must be within the range of 40 ~ 120 cc/ Min. Since a
small flow extend the life of the cartridge, and of the thallium cartridge .The larger
flow results in the more rapid response , a flow rate of 80 cc /Min should normally
be selected.
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3.GAS CHROMATOGRAPHY
Gas chromatography is the name given to a method of analysis that permits the
continuous measurement of the amounts of each constituent in a complex vapour or
gas mixture. It is the method which physically separates and quantitatively identifies
two or more components of a mixture. This method involves combining the sample
gas with a carrier gas (such as helium , nitrogen , air or hydrogen and passing the
combination of gasses through a packed chromatographic column , which is made of
metal tubing and filled with an adsorbent such as activated alumina , silica gel , or
activated carbon and operated at a suitable temperature . The rates at which
individual components move through the column depend on their respective affinities
for the column material . Therefore , the different components emerge from the
column in a sequence which depends on the relative affinity of these components for
the particular column packing . Generally the lighter components are swept always
(eluted ) faster than the heavier. In other words as carrier gas transports the sample
through the column , the column packing exerts a differential retarding effect on the
sample components , separating and regrouping them so that all molecules of an
individual component emerge in a discrete bunch . By use of the proper column
length, the components are separated from each other , and the individual elution
time serves to identify the particular component. The efficiency of separation
depends on the size , composition and made of injection of the sample : type and
rate of flow of carrier column length , area and packing material ; column
temperature.
Thus when a gasses passes through the column , its constituents get separated out
and each constituents travels through the column at a different rate , because each
is retained for a different period of time by the column adsorbent . A gas
chromatograph neither identifies nor measures components directly. For this
purpose it employs a device which detects each component as it emerges out of the
column and sends a signal to recording device that records the effect as a physical
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ANALYTICAL INSTRUMENTS
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PACKED
COLUMN
Thermal Conductivity
Detector
CARRIER
GAS
Vent Gas
Regulating
Valve
measurement (peak) which can be calibrated to yield a quantitative value. Thus
identification of a component is made by measuring the time required for a
component to move through a column operating under specified conditions; and a
quantitative determination is made by measuring peak area or height . Calibration of
peaks is accomplished by inferential methods like running a sample of known
composition and comparing the results with those obtained by other analytical
methods .Chromatograph consists of two basic sections : analysis which is located
in the field near the sample point , and control section which is located in a central
control room. The analysis portion consists of valves , columns , detectors etc. . The
control room section consists of programmer , recorder, stream selector, peak picker
memory unit, and other auxiliary units. The carrier gas is used to force the sample
gas through the column and thus the constituents of the sample gas leave the
column in combination with the carrier gas . For best results , the flow, pressure and
temperature must be controlled and recorded.
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IFFCO
AONLA
09
TOPIC:
ANALYTICAL INSTRUMENTS
Page 46 of 46
UKS