Optimum Operation and Maintenance of Gas Turbines Offshore

Abstract

At present, offshore gas turbines are operated encouraging high thermal efficiency and low power consumption. High thermal efficiency normally demands operation close to full load, which may increase the emission of specific components. The present emission tax on CO2 has a substantial impact on gas turbine operation and maintenance costs. At present, it is of great importance to include the influence of emission taxes by focusing on optimum energy operation and maintenance. The influence of gas turbine degradation on operating costs is high. Analysis based on operational experience and field test performance data show an extra cost due to deterioration up to NOK 4.5 million a year. To obtain optimum energy operation and maintenance for the gas turbine drivers on Sleipner A, analysis and developments are based on: • on-line condition monitoring, to detect machinery condition and component degradation • prediction routines, to forecast degradation “development” as a function of time • optimisation routines, to predict optimum intervention time based on operating and maintenance costs • sensitivity analysis, including site performance correction to actual operating condition The developed procedure has resulted in increased flexibility and availability, in addition to reduced operating and maintenance costs. Total potential savings are estimated up to NOK 2.5 mill. per gas turbine a year. The system forms an important tool in future operation of the 60 gas turbines in present service.