Compressor performance Impact on Rundown Characteristics

An important issue related to compressor operation is the behaviour during trip. Experience at Troll Kollsnes gas treatment plant has shown that the compressor characteristics are affected by the operating conditions. These shifts in performance lead to reduced flexibility in the operation of the pipeline compressors. The 40 MW variable speed electric motor driven compressors have therefore been subjected to dynamic simulation analyses to reveal the transient response. An elaborate plant model has been created with the dynamic simulation tool OTISSTM by AspenTech and tuned to represent the plant. The model is validated against actual plant tests and operating data. The paper reports experience from analyses of the compressor behaviour during rundown. The main objective has been to study the impact of altered compressor performance characteristics on the transient behaviour. The impact of performance deterioration and reduced head rise to surge are analysed. Performance variations within the ASME PTC10 and API 617 limitations are included.