Design, Installation, And Test Of A Steam Injection System On An Early Frame 3 Gas Turbine In A Combined Cycle Pipeline Compressor Station.

Abstract

The Frame 3 Gas Turbines have proven to be reliable drivers for pipeline compressor stations over the last 25 years. At Transco's combined cycle compressor station, a steam injection system for power augmentation was developed and found to be a cost effective alternative to the OEM's turbine upgrade offering. The design, build, and test of this unique steam injection system required with the "straight-through combustion" configuration of the early Frame 3 Gas Turbines is described. Due to the unavailability of basic thermodynamic design data and constraints from the OEM, three gas turbines at the station were performance tested. A performance model for the gas turbine was developed and validated. It was supplemented with steam system test data to develop the combined cycle model of the station. The model was used to assess the feasibility of, and to provide a design basis for the steam injection system. Overall combined cycle efficiency changes with steam injection system were evaluated. A steam injection system was designed, fabricated and tested to evaluate its field performance. Field testing confirmed the expected horsepower increase, but an unexpected increase in the exhaust thermocouple spreads at higher steam injection rates was also experienced. Correlation of the combustor liner vs the exhaust thermocouple readings showed some interesting characteristics of these turbines. Operating guidelines for steam injection operation are presented.