Hydrogen Enrichment Impact on Gas Turbine Combustion Characteristics

Abstract

The current research provides the impact of hydrogen enrichment on gas turbine combustion characteristics. The uniqueness of this study is it isolates the hydrogen effects while minimizing the impact of other parameters that are known to influence combustion characteristics. Experiments are carried out under high operating pressure and a wide range of firing temperatures that extend from the Lean Blow Out (LBO) limit to beyond J class firing temperature. Aerodynamic effects are isolated by using a perforated plate burner to provide a simple flame structure. The study is conducted under perfectly premixed conditions to exclude the mixing effects from the problem under investigation. Air flow, residence time, pressure and temperature are all held constant to enable back to back comparison. Hydrogen enrichment is varied from 0 to 25 percent by volume while holding the combustor exit temperature constant. No cooling air or effusion air is used in the combustion zone to ensure that there is no impact on the problem under investigation and to focus the study on kinetics effects and flame shape variation. NOx, CO emissions, LBO limits as well as flame luminosity are reported. Oxygen and carbon dioxide are measured at the combustor exit and used to ensure test integrity and for confirmation of the exit temperature. A reactor network model is used to mimic the experimental work and study sensitivity. The effective residence time in the model is varied slightly to mimic the slight change observed in flame length with hydrogen addition. This basic research provides a key resolution to the contradictory results that are typically reported in the literature for the impact of hydrogen on NOx emissions.

Hydrogen Blending into Natural Gas Pipeline Infrastructure: Review of the State of Technology

“…NO x emissions may also increase for lean premixed flame combustion systems using natural gas fuels with increasing hydrogen composition. However, Mohammad et al (2020) observe that this emissions effect is not significant in hydrogen compositions up to 25 vol % where combustion temperatures are controlled.…”

“…Lean premixed systems are heavily optimized in terms of equipment design and control, which lends to limitations in fuel flexibility. Hydrogen impacts both diffusion and lean premixed flame combustion system technologies differently in terms of NO x emissions and fuel compatibility (Kroniger, Lipperheide, and Wirsum 2017;Mohammad et al 2020;Abbott, Bowers, and James 2012).…”