Performance Benefits Using Siemens Advanced Compressor Cleaning System

Abstract

Extensive operational performance data from the Siemens Power Generation V64.3 unit in Obernburg, Germany (operated by Kraftwerk Obernburg GmbH) is evaluated. The unit was commissioned in 1996 and has been running continuously in base load operation with fuel gas to supply heat and power to a nearby chemical plant. In rare cases, fuel oil is used as a backup fuel. During the first major outage after approximately 25,000 equivalent operating hours (EOH), the Siemens PG Advanced Compressor Cleaning System (ACCS) was implemented at Obernburg. ACCS features separate nozzle systems for online and offline compressor cleaning accounting for different operating conditions. For online cleaning, the droplet size is optimized for the droplets to remain in the main air flow in order to minimize erosion effects while providing a homogeneous field over the whole air intake. With reduced rotational speed during offline compressor cleaning, erosion is less critical. Offline nozzles therefore provide higher mass flow and larger droplets in order to maximize cleaning performance for all compressor stages. ACCS, in its maximum automated version, features operation from the control room, online-washing at low ambient temperatures (officially released down to −15 °C without GT anti-icing) and minimum use of manpower. The ACCS system in Obernburg was operated according to the recommended online washing procedure. By June 2002, the V64.3 unit in Obernburg reached 50,000 EOH and the second major inspection was carried out. For this paper, operational data from the second inspection intervals (24,350–49,658 EOH) and from three performance tests with calibrated equipment are compared in order to evaluate the effectiveness of the advanced compressor cleaning system. Statistical evaluation of single-wash performance recovery and the evolution of long-term performance are presented. The effects of degradation and fouling are differentiated. It is shown that ACCS has a significant benefit for long-term engine performance.