ANALYSERS

Analysers ??

Analysers are analytical instruments used

for the analysis of composition of liquid,gases or solids.They

basically rely on the phenomenon of interaction of energy with

matter to quantify the sample composition.

Analyser classification:

ENERGYINTERACTING

CHEMICALAFFINITY & REACTIVITY

ELECTROMAGNETIC RADIATION

ELECTRIC OR

MAGNETIC FIELD

THERMAL &MECHANICAL

ENERGY

Analysing system schematic:

SAMPLECONDITIONING

SECTION

ANALOG O/P& DISPLAY

ANALYSING SECTION

Practical Consideration

Sample must be representative

Physical state of sample

Uniqueness of specificity of method

SAMPLE CONDITIONING:

Sample extraction

Tuning sample parameters

Stratification free sampling

DRAIN

SAMPLE INLET

COOLING WATER IN

COOLING WATER IN

PRESSURE

TEMP

TO SECONDARY SAMPLE CONDITIONING

Field Sampling Unit:

CONDENSATE POT

DRAIN

TO COMMON VENT

BYPASS ROTAMETER

SiO2 FILTER

ZERO GAS

SPANGAS

SAMPLE INLET

TO ANALYSERSECTION

Secondary Sampling Unit:

IR-Based Analysers:

It is based on the principle of characteristic

absorption of infrared radiation by molecules of the sample.The

molecules absorb infrared radiation at a particular wavelength.the

degree of absorption can be correlated to the composition of that

particular molecule

Reference cell

Sample cellElectronics

O/P

IN OUT PhotodetectorsIR- Source

General Schematic of IR -Analyser

Thermal conductivity based analysers

Distinguishing ability of some gas molecules to get highly excited and conduct large amount of heat.The amount of heat carried away from hot bodies can be used to determine gas molecules.

0

1

2

3

4

5

6

7

1 2 3 4 5 6 7 8

CO

H2

N2 O2CH4

NH3CO2

Thermal conductivityGraph

Unit:ergs/s cm deg

POWER SUPPLY

General Schematic of Thermal Conductivity Based Analysers

O/P

Chemiluminescence Type of Analysers

•Emission of light by electronically excited reaction product

E=hv

Ground state

Excited state

NH3SCRUBBER

S.S CONVERTER

MOLYCONVERTER

ELECTRONICS

OZONATORDRY AIR

REACTION CHAMBER

O/P

DISPLAY

EXTERNAL PUMP

VENT

Thermoenvironmental make NH3 analyser schematic (Location :DAP Stack)

Sample

Chemical Affinity Based O2 Analysers:

Zirconia has a tendency to attract O2 molecules at elevated

Temperatures .When electrodes are placed at both sides of

zirconia probe,an EMF is generated proportional to the difference

in partial pressure of oxygen between the reference and sample

sides.

Pt electrode

Pt electrode

VZrO2 probe

O2 in reference

O2 in sample

O2 anlayser schematic:

Service : Boiler Flue Gas Analysis