Experimental Investigation of the 4th Generation DLE Burner Concept: Emissions and Fuel Flexibility Performance at Atmospheric Conditions

Abstract

The “4th Generation DLE” (4G-DLE) gas turbine burner has been developed at Siemens Industrial Turbomachinery AB in Finspong, Sweden (SIT). The present document describes the design concepts of the 4G-DLE burner; emission performance and fuel flexibility capacity. These features were explored at atmospheric conditions at SIT. High concentrations of H2 and N2 mixed with natural gas were used in the experiments. Emissions (NOx, Unburned hydrocarbons, CO), combustion dynamics and temperature operation range were evaluated. Moreover, operation characteristics of the burner were investigated through forced flashback, flameouts and unfavorable ignition situations. The fuel flexibility concerning H2 stretched up to 90% vol. in a mixture with natural gas. In the case of N2 it was possible to use over 50% vol. mixed with natural gas. The operation was stable in all cases. The 4G-DLE burner showed good NOx emission performance that was linearly dependent on the flame temperature, while CO levels were also low. This fact reveals the high mixing level achieved in the burner. Finally; the burner operated over in a wide flame temperature range (approximately 200 K), showing both good stability and good emission levels.

Effect of Change in Fuel Compositions and Heating Value on Ignition and Performance for Siemens SGT-400 Dry Low Emission Combustion System

“…The increase in NOx emissions and reduction in CO emissions is generally reported by buming hydrogen enriched fuel [1][2][3]. NOx was increased by almost 25% when about 10% H2 was added [1]; NOx was increased 50% at 70% H2 and CO was reduced 50% at 90% H2.…”

“…The higher the H2 percentage in the fuel, the more susceptible the system is to flashback. Flashback and fiameholding did occur when 90% H2 was added [2] and it was possible to operate with such high H2 level with carefully control through pilot split and modification of operation parameter; for example, flame temperature. Flashback and fiameholding did occur when 90% H2 was added [2] and it was possible to operate with such high H2 level with carefully control through pilot split and modification of operation parameter; for example, flame temperature.…”

“…The considerations for such nonstandard fuels for industrial gas turbine combustion systems are the robustness of the combustor to autoignition, flashback, acceptable combustion dynamic pressure amplitude, and emissions and neutral flameholding [1][2][3][4][5][6][7][8], This presents a design challenge for industrial gas turbines to ensure reliability with varying fuels across an operational range.…”

“…The benefit of NOx reduction by using normal MCV fuels was widely reported [1,[9][10][11][12][13][14], for example; 20% reduction with 35% N2 in the fuel [1], 40% reduction with 50% N2 in the fuel [2] and about 50% reduction with 35% CO2 in the fuel [6]. NO^ is also sensitive to the selection of diluents, generally more NOx is produced if N2 is selected as diluent [7,9].…”

“…Flameholding is about the flame attachment to bumer and has direct impact on flame instability. This critical point is highly dependent on burner design; for example: 25% of N2 [1]; 55% of N2 [2] with frequency less than 100 Hz (between 45-50% of N2 there is a reasonable safety margin for instability); WI 27 MJ/Sm^ [6] corresponding to 22.8% CO2 and 8.2% N2 in the fuel; 20% CO2 for a 10 MW engine test [13] with a frequency shift towards to the lower value for the frequency band 40 to 45 Hz. Lafay et al [15] identified that flame instabilities, resulting from low frequency pressure oscillation, can appear below a critical equivalence ratio value when diluting premixed flames with CO2.…”