Hydrogen is an option for storing energy from renewables and surplus electricity. Hydrogen is also a major constituent in various streams in the chemical industry and sometimes available for power and heat generation using gas turbines. Siemens Energy has sold two 24MWe SGT-600 3rd generation DLE to be operated on chemical industrial gas with up to 60 vol-% hydrogen and achieving emissions below 25 ppm NOx@15%O2 to be commissioned summer 2021. The same burner is also used in the 33MWe SGT-700 and the 62MWe SGT-800, and a test performed in summer 2021 using a burner sector in an SGT-800 have led to a sales release on hydrogen contacts up to 75 vol-% hydrogen.
An alternative for hydrogen storage is ammonia, a worldwide commonly distributed chemical. Fundamental combustion tests have been performed in a small-scale SGT-750 burner at NTNU and Sintef laboratories in Trondheim Norway. An experimental study aimed at finding optimal NH3-H2-N2 fuel blends to be used in gas turbines and provide manufacturers with guidelines for their use in retrofit and new combustion applications. The overall behavior of the burner in terms of stability and emissions is characterized as a function of fuel mixtures corresponding to partial and full decomposition of ammonia. It is found that when ammonia is present in the fuel, the NOx emissions although high can be limited if the primary flame zone is operated fuel rich. Increasing pressure has shown to have a strong and favorable effect on NOx formation.
Adjunct Professor, Chalmers University