Bernhard Schetter

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

A FUEL OILPREMIX BURNER FOR GAS TURBINES - DEVELOPMENT AND INITIAL OPERATING EXPERIENCE

Premix combustion of natural gas in Siemens hybrid burners has been carried out successfully in gas turbine power plant since 1986 and has enabled NOx emissions below 10 ppm to be achieved without additional water or steam injection.Based on this experience, the hybrid burner has been further developed for the premix combustion of fuel oil and is now in commercial operation in a Siemens Model V94.2 gas turbine at the Halmstad power plant in Sweden. The final testing of the new burners on site was carried out from January to September 1993 by courtesy of and in a fruitful cooperation with the client, SYDKRAFT AB.This paper sets out a number of requirements for successful premix combustion of fuel oil, describes how these requirements have been met and concludes with the results of site measurements of NOx and CO emissions.Base load NOx emissions were reduced to less than a quarter of their previous values without additional water or steam injection.Copyright

A 9.25 MW Industrial Gas Turbine With Extreme Low Dry NOx and CO Emissions

In cooperation between Siemens and MAN GHH an industrial gas turbine with an ISO rating of 9.2 5 MW was equipped with a dry low NOx combustion system. Using the hybrid burners of Siemens gas turbines, a new combustion chamber was developed for the gas turbine THM 1304 of MAN GHH. This gas turbine has two V-like arranged combustion chambers, which allow a redesign of the combustion chamber, without changing the remaining parts of the gas turbine and its casing. So it is possible as well, to fit present machines with new combustion chambers. The combustion chambers contain flame tubes of Siemens technology with ceramic tiles and the well proved hybrid burners. After calculation and design the air flow was examined in an isothermal flow model. Finally two prototypes of the combustion chamber mounted on a THM 1304 gas turbine were tested at the MAN GHH gas turbine test bed. Success came very quickly and the test runs are finished now. So for the first time the transfer of the well-known low emission values of the Siemens large scale gas turbines succeeded to an industrial gas turbine of the 10 MW class.Copyright