ANALYZERS USED IN COMBUSTION AND POST- COMBUSTION OPTIMIZATION
2
BTU , C1-C5 +
SERVOTOUGH Laser 3 Plus Combustion
SERVOTOUGH SpectraScan 2400
O 2
AIR
CO + CH 4
3
NH 3 Dilution Air
SERVOTOUGH FluegasExact 2700
Properties of the incoming natural gas fuel can be used to optimize the combustion process along with monitoring the fuel / air ratio , especially when using a DLN combustor . This is important with the advent of fracking , as pipeline gas quality had been very predictable , but now propane or ethane increases are unexpectedly seen .
The SERVOTOUGH SpectraScan 2400 analyzer [ 1 ] provides BTU , caloric value and Wobbe index information allowing for rapid adjustments ensuring that the turbine is not running too hot .
Extreme care is needed upon start-up of the GTCC in order to not damage the steam turbine ( ST ) equipment . Therefore , the plant generally starts in a simple cycle mode using the gas turbine ( GT ) only until it is fully up and running . Only then will the ST be turned on , allowing the plant to now function as a GTCC plant .
The SERVOTOUGH Laser 3 Plus CO + CH 4 Combustion analyzer provides the CH 4 signal for safe operation during start-up , providing significant saving in the amount of air required to flush the HRSG . Once the turbine is operational , the CO signal is then used to monitor fuel combustion efficiency [ 2 ].
On the air inlet side , the open path Tunable Diode Laser ( TDL ) SERVOTOUGH Laser 3 Plus Combustion analyzer for O 2 or the SERVOTOUGH FluegasExact 2700 provides fast response for measuring or determining the fuel / air ratio needed in the feedback control [ 3 ]. Where the shear forces are high due to the turbine flow , the Laser 3 Plus analyzer is the best option for an accurate , long-lasting analyzer .
Selective Catalytic Reduction ( SCR ) and Selective Non-Catalytic Reduction ( SNCR ), uses NH 3 and O 2 to reduce any NOx present in the turbine exhaust into N 2 and water . Most GT use SCR ; however both processes rely on accurate NH 3 dosing levels to remove NOx and limit the amount of NH 3 that gets past the catalyst ( called NH 3 slip ).
Monitoring prevents downstream equipment fouling from acid formation or particulate from reactions with ammonia .
P12