Infrared gas analyzer

Infrared Gas Analyser

IR Gas analyzer:

An infrared gas analyzer measures or traces a specific gas in a sample gas, this measurement is comprised by determining the absorption of an emitted infrared light source. Gases on Earth's atmosphere are getting excited to a specific wavelength in the infrared range. So by testing how much of the infrared light of a specific wavelength is absorbed by the sample we can measure a specific gas concentration.

Fortunately, different molecules of gases in the atmosphere absorb different frequencies of infrared light. Air with a high concentration of a certain gas will absorb more quantity of a certain frequency of infrared light, allowing the sensor to report a high concentration of the corresponding molecule of gas in the sample,

Types of Infrared analyzer

Infrared or IR Gas analyzer are divided into two main types

1. Non-Dispersive IR-Analyzer

2. Dispersive IR analyzer

Working Principle of infrared gas analyzer

The main components of an Infrared analyzer are

1. an infrared source

2. sample chamber or light tube

3. wavelength sample chamber

In an IR gas analyzer concentration of a specific gas is measured electro-optically by its absorption of a specific wavelength in the infrared (IR).

First of all IR light produced by an IR source is directed through the sample chamber towards the detector. This sample chamber contains the sample gas.

In parallel with this chamber is another chamber called reference chamber, with an enclosed reference gas, typically this reference as is nitrogen.

An optical filter is placed in the front detector, function of the filter is to eliminate all IR wavelengths except the wavelength that the selected gas molecules can absorb.

Thinking ideally other gas molecules present in the sample gas do not absorb this wavelength of IR light.

The IR signal from the IR source is usually chopped or modulated so that thermal background signals can be offset from the desired signal.

NDIR Non dispersed Infra Red analyzer

A non-dispersive infrared sensor or NDIR sensor is a simple spectroscopic device often used as gas. detector. It is called non-dispersive because the wavelength which passes through the sampling chamber is not pre-filtered instead a filter is used before the detector

This analyzer measure or traces the gas by determining the absorption of an emitted infrared light source through a sample gas. Different gases absorb a specific wavelength of infrared range so to measure a specific gas a specific wavelength of infrared is emitted to measure that gas. Analyzers usually have two chambers a reference chamber and a measuring chamber.

Parts of the gas analyzer sampling system

- Sampling probe made up of SS (diameter 60 mm total diameter 100mm thickness 20mm)

- Gas extractor heater and SS filter temperature up to 150 centigrade

- Sampling tube PVC or copper is heated up to 100

- MOV (motor-operated valve) for purging 110v limit switches for close and open indication

- Drain separator having drain pot filled with water

- Gas conditioner

- sampling Pump or gas aspirator suction -250m bar

- Gas cooler temperature 2 centigrade

- SOV for calibration gases

- Rota Flowmeter 0.6 liters per mint

Membrane filter

- IR analyzer unit 1

- NO2 to NO converter

- Membrane filter

IR unit 2

- Oxygen zirconium analyzer 800 centigrade temperature

- Drain out

Calibration of gas analysis

Zero calibration of gas analyzer

The flow of gas should be set to 0. 60 L/ minute

For zero calibration a gas having nil gas is used

For Oxygen CO 1% is used, For CO and NOX Oxygen 21 %is used

Span Calibration of gas analyzer

For Span calibration, a gas having a maximum concentration of that gas which is being calibrated is used Oxygen 21 %, CO 1 %, NOX 2000 PPM

Calibration gases

N2+CO Gas 1% CO, N2 Balance Cylinder V: 3.4 Weight: 6.2 Required Pressure: 150Bar

Air Dry And Higher than 90% Cylinder V: 3.4 Weight: 6.2 Required Pressure: 150Bar

N2+O2 Gas 1% O2, N2 Balance Cylinder V: 3.4 Weight: 6.2 Required Pressure: 150Bar

N2+NOx Gas 2000ppm NOx, N2 Balance Disposable Cylinder

N2 Gas Cylinder V: 3.4 Weight: 6.2 Required Pressure: 150Bar

NOX SPAN 2000 PPM

CO SPAN 1 %

O2 SPAN 1% for fuji

zero gas is balanced nitrogen

abb analyzer el 3020

zero gas is No2

SO2 4946mg/cm2

co 1913 mg/cm2

No 2991mg/cm2

Common faults in gas analyzer

* Probe chokes.

* Primary SS filter choke

* Mist filter choke

* Membrane filter damaged or choke

* Flow is less

* Water level is less

* Leakage in the sampling system

* Pump faulty

* Calibration is out

* SOV faulty

* Purging MOV leak

kiln inlet analyzer details

probe pipe wid inlet body

dia is 130 mm

PID settings of oxygen temp controller pxr4 fuji

p=12

i=51

d=10

coal bag house analyzer

oxygen analyzer was off its temperature controller was faulty replaced with a new controller. PID

adjusted and normally open contact is used. thermocouple type is R.

NO2/ NO convertor

uses a catalyst its temperature is maintained to 220 degrees centigrade. if the temperature is not ok it will give a wrong value of NOX. and if calibrated it will show error 15 means the sensor is not cleaned etc. control voltages of fuji are 110 V AC . so all parts are if 110-volt rating.

The oxygen analyzer temperature must be 800 degrees centigrade.

the cooler temperature in ABB

is maintained to 2 to 5-degree centigrade.

the temperature of the sampling line is maintained to 100 degrees centigrade. to avoid the formation of moisture in the line.

N2+CO Gas 1% CO, N2 Balance Cylinder V: 3.4 Weight: 6.2 Required Pressure: 150Bar

Air Dry And Higher than 90% Cylinder V: 3.4 Weight: 6.2 Required Pressure: 150Bar

N2+O2 Gas 1% O2, N2 Balance Cylinder V: 3.4 Weight: 6.2 Required Pressure: 150Bar

N2+NOx Gas 2000ppm NOx, N2 Balance Disposable Cylinder

N2 Gas Cylinder V: 3.4 Weight: 6.2 Required Pressure: 150Bar