Second-Generation Low-Emission Combustors for ABB Gas Turbines: Burner Development and Tests at Atmospheric Pressure

Based on fundamental research concerning swirling flows, including the vortex breakdown phenomenon, as well as on stability considerations of premixed flames, a second generation of low-emission burners has been developed. The lean premixing technique provides NO_x emissions below 25 ppmv for natural gas. For liquid fuels the oxides of nitrogen are limited to 42 ppmv (oil No. 2). The novel burner technology will be applied to the well-known ABB silo combustor. As a first step the Conical Premix Burner will be used to retrofit the ABB type 11N. For the ABB gas turbine type 8 the design of a novel fully annular combustor is in progress. Most of the conceptual work concerning burner aerodynamics and burner-burner interaction has been carried out on scaled-down burner and combustor models. For a second step a sector of the combustor in 1:1 scale has been tested at atmospheric pressure. Additional high-pressure tests provide information about the combustor performance at engine conditions. The present paper summarizes the results of the first two steps beginning with the early ideas in the conceptual phase up to the 1:1 tests, which prove the low-NO_x capability for both gaseous and liquid fuels under atmospheric pressure conditions.