Testing of a Hydrogen Diffusion Flame Array Injector at Gas Turbine Conditions

Abstract

High-hydrogen gas turbines enable integration of carbon sequestration into coal-gasifying power plants, though NO_x emissions are often high. This work explores nitrogen dilution of hydrogen diffusion flames to reduce thermal NO_x emissions and avoid problems with premixing hydrogen at gas turbine pressures and temperatures. The burner design includes an array of high-velocity coaxial fuel and air injectors, which balances stability and ignition performance, combustor pressure drop, and flame residence time. Testing of this array injector at representative gas turbine conditions (16 atm and 1750 K firing temperature) yields 4.4 ppmv NO_x at 15% O₂ equivalent. NO_x emissions are proportional to flame residence times, though these deviate from expected scaling due to active combustor cooling and merged flame behavior. The results demonstrate that nitrogen dilution in combination with high velocities can provide low NO_x hydrogen combustion at gas turbine conditions, with significant potential for further NO_x reductions via suggested design changes.

Keywords:

• Array injector
• Diffusion flame
• Dilute fuels
• Gas turbine combustor
• Hydrogen

ACKNOWLEDGMENTS

The authors gratefully acknowledge the support of Rich Dennis and the DOE Office of Fossil Energy's Advanced Hydrogen Turbine program. The authors also wish to thank Mark Tucker and Jeff Riley for assistance with and operation of the SimVal combustor, and Steve Beer for assistance with the mass spectrometer and gas sampling system.

As part of the National Energy Technology Laboratory's Regional University Alliance (NETL-RUA), a collaborative initiative of the NETL, this technical effort was performed under the RES contract DE-FE0004000. This project was funded by the Department of Energy, National Energy Technology Laboratory, an agency of the United States Government, through a support contract with URS Energy & Construction, Inc. Neither the United States Government nor any agency thereof, nor any of their employees, nor URS Energy & Construction, Inc., nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Notes

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