Shinichi Kajita

Evaluation of a Catalytic Combustor in a Gas Turbine-Generator Unit

As a final step of the Catalytic Combustor Development Program, a catalytic combustor developed was tested in a 150-kW gas turbine-generator unit. A digital control system was developed to improve its controllability for a transient operation, and a 200-hr continuous operation test was performed to asses the durability of the catalyst. During the test, an excellent performance of the control system was verified, and a very high combustion efficiency of more than 99% and a ultra-low NOx level of less than 5.6 ppm (at 15% O2) were achieved at a 150-kW generator output. In addition, the combustion efficiency has been maintained at over 98% for 200 hours of operation. However, the catalyst exposed to 200 hours of operation showed signs of deactivation.Copyright

Development of a Second Generation Dry Low NOx Combustor for 1.5MW Gas Turbine

Development of a second generation dry low NOx combustor for KHI’s 1.5MW industrial gas turbine M1A-13A is described. A lean pre-mix and multiple burners design was tested on a bench-scale can combustor using methane gas for fuel. Effects of key design variables on combustion characteristics are evaluated. The key design variables include the air flow distribution within the combustor, swirler angle, injector position relative to the swirler, and air/fuel distribution. Emission results obtained by the optimization of these design parameters were NOx < 10 ppm (at 15 % O2), CO < 15 ppm (15% O2), and negligible THC at the rated load in the engine test.Copyright

Development of a Catalytic Combustor for Small Gas Turbines

To reduce NO/sub x/ emissions significantly, a catalytic combustor was developed. Full scale tests of catalytic combustors designed for application in Kawasaki S1A-02 type gas turbines were conducted. The combustor consisted of a pre-combustion zone, a premixing zone, a catalytic combustion zone, and a variable geometry dilution zone. Liquefied Natural Gas (LNG) was burned in combustor rig tests and results indicated low NO/sub x/ emissions and high combustion efficiencies over a wide range of air/fuel ratios and that the catalytic combustor can be applied to the engine tests.

An Advanced Development of a Second-Generation Dry, Low-NOx Combustor for 1.5MW Gas Turbine

Advanced development of a second-generation dry, low-NOx combustor for KHI’s 1.5MW industrial gas turbine, M1A-13A, is described. In this advanced development, efforts were made mainly to improve combustion efficiency in addition to NOx reduction experimentally. The combustion liner was extended to increase combustion volume, and supplemental burners were installed downstream of multiple main burners to broaden low-NOx operation range. In consequence of the optimization of the fuel allotment, air/fuel ratio at each burner, cooling air, and so on, the engine showed NOx emissions under 15 ppm (15% O2), and a combustion efficiency more than 99.5% over the range between 75% and 100% load. Finally, by means of a 300-hour operation at full load and a 500-cycle endurance test, the total reliability of this combustion system was ensured.© 1996 ASME

Development of a Dry Low NOx Combustor for 1.5 MW Gas Turbines

To meet strict NOx regulations, Kawasaki Heavy Industries, Ltd. has been conducting a development program of dry, low-NOx combustion system since 1989. In a first step of the development program, a multi-burner type, can combustor has been developed. The test engine, with an output of 1.5 MW, demonstrated NOx emissions below 42 ppm at 15% O2. Following the engine performance tests, a 500 cycle endurance test and a 300 hour test at full load have been conducted to assess the reliability of the combustion system developed. During these tests, no mechanical durability issues arose.Copyright

Prediction of NO and CO Distribution in Gas Turbine Combustors

An experimental and numerical investigation was conducted to assess the validity of a prediction procedure of NO and CO formed in gas turbine combustors. A premixed gas turbine combustor burning propane was used in the experimental program, and the flow, temperature and pollutants fields were measured. The prediction procedure solves the governing conservation equations of mass, momentum, energy and chemical species simultaneously by means of finite difference solution algorithm. Two main mathematical models were employed in the procedure to represent the turbulent nature of the flow and the chemical reaction rates. For the turbulence model, the two-equation k-epsilon model was applied. The chemical reaction model assumed a two step reaction, and the effect of turbulence on reaction rates is taken into account by employing the modified eddy-break-up model which considers the dissipation rate of eddy and the concentrations of fuel and combustion products. The prediction results were compared with those obtained from the corresponding experiment. The prediction results showed the correct overall features, but a quantitative agreement was not obtained for NO and CO concentrations.