Reduction of NOx Emissions in Alstom GT11NM Engines: Development, Validation and Engine Operation Experience of the EV-Alpha Burner

Abstract

The first Alstom GT11N engine was introduced to the market at the end of the eighties. In order to keep our base fleet engines (aged fleet) attractive for dispatch and therefore for operation, one of the key issues of the service business is the development of upgrade packages. For the GT11N fleet an emission reduction package was worked out in recent years with the target of single digit NOx at base load (<10 ppm NOx @15%O2). The purpose of this paper is to present the performed development work, starting from the R&D work with the CFD optimization of the mixing quality, going to the atmospheric combustion tests and finally to the engine validation tests on site. The first section of the paper focuses on the performed R&D work, mainly on the improvement of the gas/air mixing quality of the EV burner. For the down selection of the most promising configurations the calculated unmixedness at different places of the burner and the hottest flame zones were analyzed and evaluated. The second part of the paper focuses on the results of the atmospheric burner combustion tests. The last part of the paper is focusing on the verification phase and on the achieved results during the engine validation tests on site. The EV-alpha burners were implemented during an A-inspection. Before the implementation a reference measurement with the standard EV burners was carried out. This section gives an overview of the performed engine tests and achieved emissions at base load and part load, about flame stability behaviour and transient operation results. With the implementation of the EV-alpha burner the target “single digit NOx” could be achieved and the combustion stability kept at comparable levels.