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GE Oil&Gas has recently launched a new heavy-duty gas turbine, the MS5002E, which underwent an extensive theoretical and experimental study on fuel flexibility. Today, fuel flexibility is one of the most challenging requirements in the Oil&Gas market. The fuel flexible operation demands a wide variety of assessments, ranging from rig tests of the combustor to theoretical consolidation of the results. The present paper describes the used methodology to increase the capabilities of burning diverse gaseous fuels, at fixed geometry. It analyzes all factors affecting the operation of the combustor with the goal to identify and extend the boundaries. Such boundaries are a result of multiple variables, like resistance to flashback and autoignition, emissions, pressure pulsations and capability of igniting. Flashback is when the reaction velocity overtakes the flow velocity and the flame moves back to the fuel injection points, threatening the integrity of the hardware. The resistance of the MS5002E to flashback and flame holding was evaluated by performing extensive experiments on a single fuel nozzle. Flame holding test results were then used to develop a transfer function for the prediction of the flame holding behavior of different mixtures. Another variable of interest is the resistance to autoignition: MS5002E took advantage of previously defined transfer functions from GE Energy that estimate the temperature above which a given mixture is likely to autoignite, at fixed pressure. Since the MS5002E is a DLN machine, it was also necessary to exclude the possibility of lean-blow-out in the whole operating range: dedicated tests on a single-can basis were used for this scope. Emissions and pressure pulsations were extensively measured on a single-can basis, since these parameters are fundamental for a lean premixed combustor. For particular mixtures, like those with high content of inert gases, the capability of igniting repeatably and reliably is an additional requirement that needs experimental validation. The combination of all the aforementioned variables determines the composition limit of the fuel mixture that the machine can tolerate. As a result of all the assessment, it was possible to achieve an increase in the maximum allowable concentrations for the following constituents: propane (up to 20%), nitrogen (up to 20% with no modifications to the control algorithms; up to 25% with minor modifications to the control algorithms) and hydrogen (up to 5%). Future tests will deliver increased capabilities also for ethane and butane.

Interest in hydrogen as a primary fuel stream in heavy-duty gas turbine engines has increased as pre-combustion carbon capture and sequestration (CCS) has become a viable option for integrated gasification combined cycle (IGCC) power plants. The US Department of Energy has funded the Advanced IGCC/Hydrogen Gas Turbine Program since 2005 with an aggressive plant-level NOx target of 2 ppm @ 15% O2 for an advanced gas turbine cycle. Approaching this NOx level with highly-reactive hydrogen fuel at the conditions required is a formidable challenge that requires novel combustion technology. This study begins by measuring entitlement NOx emissions from perfectly-premixed combustion of the high-hydrogen fuels of interest. A new premixing fuel injector for high-hydrogen fuels was designed to balance reliable, flashback-free operation, reasonable pressure drop, and low emissions. The concept relies on distributed, small-scale jet-in-crossflow mixing that is a departure from traditional swirl-based premixing concepts. Single nozzle rig experiments were conducted at pressures of 10 atm and 17 atm, with air preheat temperatures of about 650K. With nitrogen-diluted hydrogen fuel, characteristic of carbon-free syngas, stable operation without flashback was conducted up to flame temperatures of approximately 1850K. In addition to the effects of operating pressure, the impact of minor constituents in the fuel — carbon monoxide, carbon dioxide, and methane — on flame holding in the premixer is presented. The new fuel injector concept has been incorporated into a full-scale, multi-nozzle combustor can with an energy conversion rate of more than 10 MW at F-class conditions. The full-can testing was conducted at full gas turbine conditions and various fuel compositions of hydrogen, natural gas, and nitrogen. This combustion system has accumulated over 100 hours of fired testing at full-load with hydrogen comprising over 90 percent of the reactants by volume. NOx emissions (ppm) have been measured in the single digits with hydrogen-nitrogen fuel at target gas turbine pressure and temperatures. Results of the testing show that small-scale fuel-air mixing can deliver a reliable, low-NOx solution to hydrogen combustion in advanced gas turbines.

Interest in hydrogen as a primary fuel stream in heavy-duty gas turbine engines has increased as precombustion carbon capture and sequestration (CCS) has become a viable option for integrated gasification combined cycle (IGCC) power plants. The U.S. Department of Energy has funded the Advanced IGCC I Hydrogen Gas Turbine Program since 2005 with an aggressive plant-level NO^ target of 2 ppm at 15% O2for an advanced gas turbine cycle. Approaching this NO^ level with highly reactive hydrogen fuel at the conditions required is a formidable challenge that requires novel combustion technology. This study begins by measuring entitlement NO^ emissions from perfectly premixed combustion of the high-hydrogen fuels of interest. A new premixing fuel injector for highhydrogen fuels was designed to balance reliable flashback-free operation, reasonable pressure drop, and low emissions. The concept relies on small-scale jet-in-crossflow mixing that is a departure from traditional swirl-based premixing concepts. Single nozzle rig experiments were conducted at pressures of 10 atm and 17 atm, with air preheat temperatures of about 650 K. With nitrogen-diluted hydrogen fuel, characteristic of carbon-free syngas, stable operation without flashback was conducted up to flame temperatures of approximately 1850 K. In addition to the effects of pressure, ihe impacts of nitrogen dilution levels and amounts of minor constituents in ihe fuel-carbon monoxide, carbon dioxide, and methane-on flame holding in the premixer are presented. The new fuel injector concept has been incorporated into a full-scale, multinozzle combustor can with an energy conversion rate of more than 10 MW at F-class conditions. The full-can testing was conducted at full gas turbine conditions and various fuel compositions of hydrogen, natural gas, and nitrogen. This combustion system has accumulated over 100 h of fired testing at full load with hydrogen comprising over 90% of the reactants by volume. NOê missions (ppm) have been measured in the single digits with hydrogen-nitrogen fuel at target gas turbine pressure and temperatures. Results of the testing show that small-scale fuel-air mixing can deliver a reliable, low-NO^ solution to hydrogen combustion in advanced gas turbines.

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