Intelligent Operation of Siemens (SGT-300) DLE Gas Turbine Combustion System Over an Extended Fuel Range With Low Emissions

Abstract

The use of an innovative, intelligent control algorithm applied to the Siemens SGT-300 DLE engine is described. The algorithm ensures stable operation and minimises emissions over a wide variation in fuel composition. The Siemens 8MW class SGT-300 gas turbine has been in operation at the University of New Hampshire (USA) since 2006. As well as operating on natural gas or diesel, the engine also operates on a gas processed from a landfill. These gases have a variable Wobbe Index (WI) covering the range 29.7 to 49 MJ/m3. No modifications have been required to the standard DLE combustion hardware. Introduction of the intelligent control algorithm has been instrumental in achieving this tri-fuel capability. Accumulation of more than 10 000 hours running on non-standard fuel has been achieved. The intelligent control algorithm exploits knowledge of the stable operating window through continual modification of the fuel schedule to avoid both lean blow out and high metal temperatures. Operationally, this results in a reduction in the NOx emissions, through controlling the unmixedness, and higher engine reliability, through the response of the algorithm to flame stability. Combining these advantages the control algorithm can deliver reliable engine operation on variable composition fuels when using standard combustion hardware achieving single digit NOx emissions not only on natural gas but also on processed landfill gas. This paper describes the control algorithm and presents results of the development from high pressure combustion rig and engine development test to field operation with both natural gas and processed landfill gas.

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

“…SITL DLE combustion technology is applied across the range of small-scale industrial gas turbines from 5MW to 15 MW (SGT-100 to SGT-400) [12,24,32]. The operational experience on these DLE engines has accumulated more than 20 x 10*h. Figure 1 shows the schematic view of the SITL DLE combustor.…”

“…Tbe radial swirled DLE combustor design is sufficient to generate high swirl number, greater tban 0.6 for a typical gas turbine combustor, to create a vortex breakdown reverse flow feature along tbe axis of tbe combustor [12,24,32]. Tbis flow feature is called as intemal reverse flow zone or central recirculation zone (CRZ).…”

“…Firstly, tbe main injection, which has a bigb degree of premixing and hence low NOx emissions and secondly the pilot, which is increased steadily as tbe load demand decreases, in order to ensure flame stability [12,24,32]. Firstly, tbe main injection, which has a bigb degree of premixing and hence low NOx emissions and secondly the pilot, which is increased steadily as tbe load demand decreases, in order to ensure flame stability [12,24,32].…”

“…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].…”

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

“…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% N 2 in the fuel [1], 40% reduction with 50% N 2 in the fuel [2] and about 50% reduction with 35% CO 2 in the fuel [6]. NOx is also sensitive to the selection of diluents, generally more NOx is produced if N 2 is selected as diluent [7,9].…”