Development of a Liquid-Fueled Dry Low Emissions Combustor for 300kW Class Recuperated Cycle Gas Turbine Engines

Abstract

The authors have developed a liquid-fueled, low-emissions, and single can combustor for the RGT3R, Niigata’s 300 kW class industrial gas turbine engine, with the goal of satisfying the most stringent environmental requirements for distributed power generation systems in Japan. This paper describes these development efforts, which included non-reacting Computational Fluid Dynamics (CFD) analysis and component and engine tests. The emissions target is less than 24 ppm nitrogen oxides (NOx), 60 ppm carbon monoxide (CO) and 60 ppm unburned hydrocarbons (UHCs) at dry 15% O2 correction for kerosene, while operating above 50% load. A lean premixed, pre-vaporized, axially staged combustion concept is used to minimize emissions levels to the strictest emissions regulations in urban areas such as Tokyo, Chiba, Saitama, Yokohama, and Osaka. This combustion system involves two pilot burners and two main mixture injection tubes that are extending into the combustion chamber to inject lean to ultra-lean premixed mixtures into the hot burned gas from pilot burners. Counter rotational swirl vanes are provided to pilot burners and main mixture injection tubes to prevent flashback into the premixing tubes. The RGT3R gas turbine engine operates smoothly with the developed DLE combustion system from idle to full load without combustion-driven pressure oscillations. A two-stage fuel control system employs liquid fuel supply for the pilot and main atomizers. As this paper describes, the emissions data from this engine meet the emissions goals.

Combustion of Cross Impinging Air-sheathed Spray Jets in StagnationPoint Reverse Flow

“…It is characterized by the reactions of lean to ultra-lean secondary mixtures injected into the combustion products from the lean-burn primary stage. Its advantages over the conventional two-stage approach have been demonstrated not only with gas-fueled gas turbines but also for liquid-fueled ones [1] .…”