Douglas Anthony Pennell

On Key Features of the AEV Burner Engine Implementation for Operational Flexibility

Modern gas turbine combustors have to fulfill two major requirements. On the one hand they have to provide reliable operation with low emissions; on the other operational flexibility is of utmost importance. Alstom’s new AEV (Advanced EnVironmental) burner — an evolution of the proven EV burner technology — is one key feature to fulfill both on engine level. It can be operated on fuel gas and oil. In order to achieve low NOx emissions, modern combustors are operated in lean-premixed mode which is prone to thermoacoustic instabilities. This is accounted for by the implementation of multi-volume dampers. These dampers feature high damping performance in a broad low-frequency range thus widely enlarging the operating window. During transient operation, especially when switching from gaseous to liquid fuel and vice versa, the specific switching procedure with sophisticated fuel flow control schemes allows for a very smooth transmission. Another very important aspect is the optimization of leakage and cooling air into the combustion chamber. In order to validate the reduction of both, multiple thermal paint applications for fuel gas and oil operation in the full scale engine were performed at different engine loads up to baseload. In this paper, the AEV burner, broadband acoustic dampers, optimized cooling and leakage schemes, as well as innovative fuel switchover and operation concepts are described. It is shown that the combination of all of them makes the GT13E2 outstanding in fuel and operational flexibility featuring low emissions over the whole operating window.Copyright

Development and Implementation of the Advanced Environmental Burner for the Alstom GT13E2

Increasing public awareness and more stringent legislation on pollutants drive gas turbine manufacturers to develop combustion systems with low NOx emissions. In combination with this demand, the gas turbines have to provide a broad range of operational flexibility to cover variations in gas composition and ambient conditions along with varying daily and seasonal energy demands and load profiles. This paper describes the development and implementation of the Alstom AEV (advanced environmental) burner, an evolution of the envorinmental (EV) burner. A continuous fuel supply to two fuel stages at any engine load simplifies the operation and provides a fast and reliable response of the combustion system during transient operation of the gas turbine. Increased turndown with low emissions is an additional advantage of the combustion system upgrade.

Development and Implementation of the AEV Burner for the Alstom GT13E2

Increasing public awareness and more stringent legislation on pollutants drive gas turbine manufacturers to develop combustion systems with low NOx emissions. In combination to this demand the gas turbines have to provide a broad range of operational flexibility to cover variations in gas composition and ambient conditions as well as varying daily and seasonal energy demands and load profiles.This paper describes the development and implementation of the Alstom AEV (Advanced EnVironmental) burner, an evolution of the EV. Continuous fuel supply to two fuel stages at any engine load simplifies the operation and provides a fast and reliable response of the combustion system during transient operation of the gas turbine. Increased turndown with low emissions is an additional advantage of the combustion system upgrade.© 2012 ASME

Reduction of NOx Emission of Heavy Duty Gas Turbines by Improving Mixing Quality Using CFD Tools

Jets in cross flow are one of the fundamental issues for mixing studies. As a first step in this paper, a generic geometry of a jet in cross flow was simulated to validate the CFD (Computational Fluid Dynamics) tool. Instead of resolving the whole injection system, the effective cross-sectional area of the injection hole was modeled as an inlet surface directly. This significantly improved the agreement between the CFD and experimental results. In a second step, the calculated mixing in an ALSTOM EV burner is shown for varying injection hole patterns and momentum flux ratios of the jet. Evaluation of the mixing quality was facilitated by defining unmixedness as a global non-dimensional parameter. A comparison of ten cases was made at the burner exit and on the flame front. Measures increasing jet penetration improved the mixing. In the water tunnel the fuel mass fraction within the burner and in the combustor was measured across five axial planes using LIF (Laser Induced Fluorescence). The promising hole patterns chosen from the CFD computations also showed a better mixing in the water tunnel than the other. Distribution of fuel mass fraction and unmixedness were compared between the CFD and LIF results. A good agreement was achieved. In a final step the best configuration in terms of mixing was checked with combustion. In an atmospheric test rig measured NOx emissions confirmed the CFD prediction as well. The most promising case has about 40% less NOx emission than the base case.© 2003 ASME