Post on 05-Apr-2018
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H2 PURITY ANALYZER
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WHY H2 USED AS COOLANT?
HIGH THERMAL CONDUCTIVITY
HEAT TRANSFER RATE WILL BE HIGH HENCE INCREASE
GENERATOR EFFICIENCY.
LOW DENSITY
WINDAGE/FRICTIONAL LOSSESS WILL BE REDUCED
HENCE INCREASE TURBINE EFFICIENCY.
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ON-LINE GAS ANALYSIS
1. It is used to maintain a high concentration of hydrogen coolant toensure cooling efficiency and maintain safe conditions duringnormal running.
2. Turbine needs to be opened for maintenance,the hydrogen is firstreplaced with inert CO2 and this process is tracked with theanalyzer, 0-100% H2 (with CO2 as background gas). Once all ofthe hydrogen is removed, air is injected to displace the CO2 andthis is tracked 0-100% CO2 (with air as background gas). Whenall of the CO2 has been replaced with breathing air, it is safe toopen the turbine. To restart the turbine, this process is reversed.
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TYPE OF ANALYZER
THERMAL CONDUCTIVITY ANALYZER
GAS DENSITY ANALYSER
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THERMAL CONDUCTIVITY ANALYZER
Thermal conductivity is the rate of heat transfer through asubstance. Each gas has it's unique thermal conductivity Thermalconductivity gas analyzers use this property to measure binary gasmixtures.
Typically, thermal conductivity detectors (TCD) have four filamentwires. The four filaments are arranged in a Wheatstone bridgeconfiguration.
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A current is induced through the filaments by a power supplyheating the filament wire. The temperature of the wire depends onthe thermal conductivity of the gas, which allows heat to be
transferred from the wire to the walls of the thermal conductivitydetector. Gases with high thermal conductivity, such as hydrogenconduct heat away from the wire at a high rate, and the wire cools,lowering the resistance of the wire.
Gases with low thermal conductivity, for example argon or carbon
dioxide, conduct heat away at a lower rate, causing the wire to heatup and the wire resistance to increase.
Initially, passing the reference gas through both sides of the detectorwhile the circuit is electrically zeroed with a potentiometer zeroes theWheatstone bridge circuit. Then the sample gas is introduced into
one side of the detector, causing the filaments to heat up or cooldown, resulting in a resistance change and corresponding outputfrom the bridge circuit.
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LIMITS OF USE
EXPLOSION RISK:THIS TYPE OF ANALYSER USES HOT FILAMENT SENSOR ANDUSED FOR THE MEASUREMENT OF GAS WHICH WHEN MIXEDWITH AIR CAN BUILD A COMBUSTIBLE MIXTURE.
HENCE ADDITIONAL SAFETY MEASURED SHOULD BE TAKEN.
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GAS DENSITY ANALYSER
Gas density analyzer is based on theprinciple that the resonance frequency of athin-film cylindrical vessel varies with the
density of ambient gas. It can measure thedensity of all gases, with the exception ofcorrosive gases.
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It is intrinsically safe and flameproof,explosion protected. It is designed to bevirtually maintenance free for all acceptedapplications.
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HYGROMETERS
THE PANAMETRICS MOISTURE IMAGE IS A
MICR.PROCESSOR BASED MULTICHANNEL ANALYSER
DESIGNED TO MEASURE DISSOLVED MOISTURE
CONCENTRATION IN GAS.
PROBE: IT IS A PART OF THE ANALYSER THAT COME
INTO CONTACT WITH THE PROCESS FLOW.
PROBE USE ALUMINIUM OXIDE SENSOR TO MEASURE
MOISTURE AND THERMISTOR BEADS TO MEASURE
TEMPERATURE.
MOISTURE IMAGE PROBE MEASURE MOISTURE
CONTENT IN A STANDARD RANGE FROM -110 DEGC
TO 20 DEGC DEW POINT TEMP.