Bernard Becker

Combustion System Development for Dry Low-NOx Emission and High Turbine Inlet Temperatures

The last 10 years of combustor development are characterised by the introduction of lean premixed burners for dry low-NOx emissions. This was easy to achieve as long as sufficient excess air was available. The modern gas turbine with its high turbine inlet temperature and increased need for component cooling sees a competition for air between combustion and requirements in other areas.The paper describes how these problems have been solved by changing the design of burners and combustion chambers. The goal of minimising the hot surface area for a given combustor volume is achieved with the annular combustors. The number of burners has been selected in order to achieve good cross ignition, uniform temperature distribution and reasonably short residence times with the minimum of components. Test results and experience with operation and maintenance are also reported.Copyright

Robust Gas Turbine Design

Industrial gas turbines utilize numerous design features that cannot be implemented in jet aircraft turbines for weight reasons, but because of their straight-forward and robust nature trim costs and reduce both maintenance effort and operating risks. Regardless of manufacturer, the following design features, for example, have become the established industry standard: • single-shaft rotor; • 2 bearings at atmospheric pressure; • Journal bearing instead of ball bearings; • steel blading in the compressor. For the key components compressor, turbine, rotor, and combustion chamber of its 3A family (Fig. 1 ), Siemens has developed and tested additional features that reduce wear further and improve operational reliability. Operating experience gathered to date has shown that these features enable achievements of very high reliability and availability. Some of the measures described also contribute to enhanced output and efficiency.© 2002 ASME