Generation Ramp Rate Furnace Protection at Morgantown Generating Station Coal Fired Units through Model Predictive Control

摘要

This paper is an update to the ISA POWID 2010 technical paper presented on the subject of increasinggeneration ramp rate at Morgantown Station. GenOn Morgantown Units 1 & 2 are split furnace 630MW coal fired once-thru units constructed in the 1970’s. The units were recently retrofitted with SCR’swhich altered the boiler gas path. As reported last year, the DCS logic and the dynamic NOx /heat rateoptimization system were successfully configured to improve steam temperature controls and enhanceunit ramp rate capability.Operation over the past year at higher ramp rates exposed additional opportunities for controlenhancements. The split furnace design with dual SCR systems poses unique challenges to balancingsteam temperatures and limiting peak metal temperatures in the various boiler circuits. Since high peakmetal temperatures are often a precursor to premature tube failure, control enhancements to lower peaktemperatures offer a substantial payback to GenOn. Through the expansion of the Model Predictivecontrol with further DCS based process control algorithms, the objectives of improved steamtemperature balance in the boiler circuits and lower peak metal temperatures were achieved. Thesecontrol improvements widened the load range of fast dispatch operation while protecting boiler tubesfrom excessive thermal induced stress promoting long boiler tube life.