Field Test Results of a Dry Low NO_x Combustion System for the MS3002J Regenerative Cycle Gas Turbine

A dry low NO_x combustion system for the MS3002J regenerative cycle gas turbine has been developed and successfully installed at two pipeline compressor stations. Preparation for the DLN retrofits began with initial field testing of the conventional system intended to characterize some of the unique features of the two-shaft, regenerative cycle machine that might affect the proposed premixed combustor design. Combustor transition pieces were instrumented with gas sampling probes for CO₂ analysis. Fuel flow to each combustor was measured and controlled. Consequently, the fuel/air ratio, exit temperature, and air flow for each combustor could be determined over the operating range. The dry low NO_x combustion system for the MS3002J R/C is based on an existing system for the MS6001B gas turbine. A description of the hardware and system operation is given, Because of the relatively high inlet temperature of the MS3002J R/C (950°F), some portions of the liner required highly efficient effusion cooling. A new transition piece seal was developed to reduce leakage and ensure uniform air flow throughout the machine. A control strategy was developed to guide the machine through diffusion modes of operation at low load to premixed combustion at higher loads. Results showed acceptable component temperatures throughout. Emissions measurements were consistent with previous laboratory measurements and met design targets of 33 ppm NO_x and 25ppm CO (at 15 percent O₂) over the required range. The fuel split between the two premixed flame zones was controlled over the load range of the turbine to optimize CO, NO_x, and liner temperatures. Because of the high inlet temperature and low overall temperature rise, dynamic pressure activity was low. Following a successful inspection after 6000 hours of operation, the hardware inspection interval has been set at 12,000 h.