Emission Measurement Techniques and Standards
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Transcript of Emission Measurement Techniques and Standards
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Emission MeasurementTechniques
N . S . K r i s h n a n
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NDIR
Non Dispersive Infra Red Sensors
Electro optical measurement of gas by IRabsorption
Spectroscopic Device
CO2 , NO2 , CH4, SO2, etc.,
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NDIR
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NDIR Components
Infrared Source
Sample Chamber
Wavelength Filter
Infrared Detector
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NDIR Working
Sample gas into chamber
Reference gas Nitrogen
CO2 absorbs IR radiation
Amount of absorption is measuredby optical sensor
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NDIR Working
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Advantages of NDIR
High Accuracy
Extremely versatile
Less time for measurement
Low power consumption
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Disadvantages of NDIR
Needs compensation since H2O also absorbs
IR radiation of same wavelength
Low concentration of NOx and SOx cannot be
determined in case of high COx
Expensive
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FID
Flame Ionization Detector
Gas detector used in gas chromatography
Effective method for detecting Organic Compound
Presence of carbon makes FID more suitable thanany other element
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FID Principle
Hydrogen Oxy flame or Compressed air flame
Pyrolyze the organic compound
Positive Ions and Electrons are formed
Tubular Electrodes produce current from the ions
Current is fed to pico ammeter
Carrier gas flow is not a constraint
Detector is more sensitive to mass rather thanconcentration
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FID
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Advantages ofFID
Contaminated effluents can be measured
accurately
More rugged High concentration can be
measured
Sensitive measuring elements after the FIDare not damaged by the intensity of the
effluent
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Disadvantages ofFID
Insensitive to Metallic and Organic Oxides (Alcohol,
Ketone, Aldehyde , Acid, Carbonyl, Amines, Halogens,
etc.,)
FID destroys the sample so it cannot be used for any
further analysis
It should be the last stage of measuring the gas
sample
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ChemiluminescentAnalyzers
Most used method for measuring Oxides of
Nitrogen
Reaction between Ozone and NO forming
exited NO2
NO emits light with intensity proportional to
NO concentration
Photo multiplier tube for light measurement
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Advantages of ChemiluminescentAnalyzers
Internationally accepted method for
measuring oxides of nitrogen
Accurate measurement of NO
Sulfur can also be analyzed by this process
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Disadvantages of ChemiluminescentAnalyzers
Only NO and N2O can be measured
NOx has to be converted into NO for
measuring
Ozone is expensive at this rate of use
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Gas Chromatography
Gas chromatography is used for analyze compounds
that vaporize without decomposition
Separates gases with different chemical composition
and adsorption of gas with respect to temperature
It is dependent on vapour pressure of the gas
Similar to fractional distillation
Vapour phase chromatography or Gas - Liquid
partition chromatography
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Gas Chromatography
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Smoke Meter
Smoke is Visible part of the emission
Incomplete combustion
Comparison method
Obscuration method
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Ringelmann Chart
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Light Extinction Method
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Hartridge Smoke meter
Similar to Light Extinction method
Reference tube
Light source and Photo electric cell
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Continuous Filter Type Smoke meter
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SpotFiltering Type Smoke Meter
Exhaust forced to a spot of the filter paper
Pump is used to force the air
Bosch Smoke meter is an advancement of this
type
It consists of pneumatic tripping devices andelectric output instead of comparison
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Thank You