The current proposed ASTM GT fuel oil specifications for gas turbines imposes certain limits on contaminants. This paper presents some operating experiences with two gas turbines using a fuel oil that approaches these maximum limits for vanadium and sodium for the proposed Nos. 1, 2, and 3 GT fuels. One year’s satisfactory operation was achieved although evidence of minor corrosion was present, but insufficient to cause replacement of components.

This paper describes the actual operating experience of a current technology combustion turbine, burning residual fuel, operating under actual utility conditions. The objective of the program was to demonstrate that combustion turbines utilizing air-cooled blades and vanes were capable of performing in an economical, reliable and satisfactory manner to meet the demands of a utility company in normal daily cyclical duty. Included in the program was an evaluation of a fuel treatment plant with associated fuel-handling requirements, resistance to corrosion of numerous blade and vane alloys both with and without protective coatings, plus optimization of a turbine cleaning system to remove turbine blade path deposition.

In recent years there has been an increased interest in the burning of ash forming liquid fuel oils including applications where fuel treatment is required. The final decision of fuel type to use depends on several economic factors. These include the delivered price, cost of fuel treatment, cost of modifying the fuel handling system, and the increased maintenance costs associated with the grade of fuel. The ultimate decision on the burning of any fuel, including those fuel oils which require treatment is generally an economic choice, rather than a technical choice. There is however a broad end user lack of knowledge and understanding of the implications of burning ash forming liquid fuel oils. There is only limited documentation available detailing the considerations required to allow the upper and lower economic factors to be bounded. It has been demonstrated that with careful attention to the fuel treatment process and the handling and operating practices, combustion turbines can, within certain limitations, successfully burn a wide range of liquid fuels.

Over three years of successful operating experience with a dry low NOx combustor and SCR system used in a combined cycle power plant of a Japanese utility is presented. The dry low NOx combustor with pre-mix fuel nozzles was verified by field test at a NOx level of 65 ppm. The SCP system has been operated with an efficiency between 30% and 90%, and shows no degradation in 20,000 hours operation.

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