Development Of Fuel-Flexible Gas Turbine Combustor

LectureGrowing global energy demands are motivating the gas turbine industry to seek fuel-flexible gas turbines capable of burning a wide variety of fuels as a means of increasing energy supply stability and security. These fuel-flexible gas turbines require diluent-free (“dry”), low nitrogen oxide (NOx) and flashback-resistant combustors for various fuels in order to achieve low NOx emissions and high plant efficiency for low carbon dioxide (CO2) emissions. This paper describes the development of a state-of-the-art dry low-NOx and flashback-resistant combustor for fuel-flexible gas turbines. This advanced combustor consists of multiple fuel nozzles and multiple air holes. One fuel nozzle and one air hole are installed coaxially to give one key element, and a cluster of key elements constitutes one burner, which forms one flame. Multiple cluster burners constitute a can combustor, and several can combustors are installed on a gas turbine. In this paper, the burner is called a “cluster burner,” and the combustor is called a “multi-cluster combustor.” The essence of the burner concept is the integration of two key technologies: low-NOx combustion due to the enhancement of fuel-air mixing; and flashback-resistant combustion due to short premixing sections, air-stream-surrounded fuel jets and lifted flames. The development approach of the multi-cluster combustor consists of three steps: burner development; combustor development; and feasibility demonstration for practical plants. The first step optimizes burner configurations by fundamental research at atmospheric pressure. The second step optimizes combustor configurations by single-can combustor testing at medium to high pressures. The third step demonstrates the feasibility of the combustor by field testing with real gas turbines. This paper describes the development work in each step of the multi-cluster combustor developed particularly for hydrogen content syngas fuels in a coal-based integrated gasification combined cycle (IGCC), and the field test in an IGCC pilot plant demonstrates the feasibility of the combustor for practical plants. This paper also describes applications of this combustion technology to expand fuel flexibility