Optimization of SCR system at Cayuga Unit 1
Carlos E. Romero, Zheng Yao, Fengqi Si, Eugenio Schuster, Robert L. Morey, Jacob A. Peter, Barry N. Liebowitz
International Pittsburgh Coal Conference
Pittsburgh, Pennsylvania, September 29-October 2, 2008
Abstract
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AES Cayuga Unit 1 is a 160 MW unit, equipped with a low-NOx firing
system and an anhydrous ammonia (NH3), Selective Catalytic Reduction
(SCR) system for NOx emissions control. A combined boiler/SCR/air
preheater (APH) optimization was performed to minimize the cost of
NOx emissions control. Boiler and low-NOx system control settings, and
SCR and air preheater (APH) operating conditions were included in a
parametric test program. Information from a Breen Energy Solutions
ammonium bisulfate (ABS) probe was also included for monitoring of ABS
formation in real-time and as a constraint to the SCR optimization.
The parametric test data were used as the basis for the optimization
that consisted of an approach that incorporates accurate on-line
support vector regression (AOSVR) modeling for adaptive learning, and
genetic algorithms for implementation of the multi-objective
optimization. The results indicate that optimal operating conditions
can be achieved for a coordinated boiler/SCR/APH operation, and minimal
NH3 consumption, maximum SCR performance, and optimal net unit heat
rate, subject to minimal impact on fly ash unburned carbon content,
mitigated ABS formation, and other operational and environmental
constraints. The optimal conditions resulted in reduced NH3 usage of
the order of 25 percent, with improved APH fouling management.