Plant Construction and Commissioning - A Manufacturer’s Viewpoint of Pre-operational Cleaning

摘要

Siemens Power Generation (SPG) has considerablernexperience in erection and the startup of combinedrncycle plants. This paper focuses on SPG’s preferredrnpre-operational cleaning concept for new WaterrnSteam Cycle piping systems. During commissioningrnthe plant is transformed from a manufactured andrnerected condition, to a clean condition, fit to run forrnpower production. The steps to achieve thisrntransformation start during the negotiation of the salernand continue through to customer acceptance of thernplant. The concept sets forth the goals and thernimplementation process. Appropriate manufacturingrnand erection cleanliness are critical to the timelyrncompletion of the chemical commissioning of thernplant. In spite of the care in manufacturing, somerndirt does enter the plant during erection and must bernremoved. Contamination is removed in threernstages: 1) Flushing which removes particulate; 2)rnchemical cleaning which removes the solublerncontamination without leaving residues that wouldrnslow startup of the boiler system and; 3) steamrncleaning which further cleans and verifies thernsuccess of particulate removal.rnAn example from the flushing and chemical cleaningrnof systems at a W501G - Combined Cycle PowerrnPlant will be used to illustrate specific points. Thernpre-operational cleaning of this plant with its lowpressurern(LP) steam generator serving as a feedrnwater source for the intermediate-pressure (IP) andrnhigh-pressure (HP) boilers, presence of kettle boilersrnas well as the requirement for Combustion Turbinern(CT) steam cooling above a load of 20% presentedrnmany unique challenges. Such a configurationrnrequired special piping arrangements and cleaningrnmethods to expedite the process. Until now,rnpractitioners have been on a learning curve for thernoptimal cleaning procedures for these units.