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