Feasibility study for the utilization of natural gas and hydrogen blends on industrial furnaces

In the deep steel industry decarbonization, green hydrogen plays a pivotal role as alternative energy to replace natural gas and carbon bearing materials. In this frame, technical aspects and in general criticalities relevant to the use of mixtures of hydrogen and natural gas in industrial processes were investigated: in particular its effect was analyzed on employ of existing industrial burners for treatment furnace and on oxidability and descaling susceptibility of forged material as Grade F22V and Inconel(R) 625. The experimental campaign on burner using blends with 30% and 50%vol. of hydrogen in natural gas highlighted that it is possible to ignite the burner for both mixtures, but that the burner is more stable with the 30%vol. of hydrogen in natural gas. The detected emissions of nitrogen oxides compared to the natural gas increase up to 15%. The results indicated that selected high speed burner should be used in industrial plant with a 30% of hydrogen in volume with no need of hardware modifications. The oxidation investigation on atmospheres deriving from the combustion of 100% of hydrogen, at 1230 degrees C, showed a moderate scale increase up to 14% for F22V grade and 8% for Inconel(R) 625. This increase of scale growth has not detrimental effect on the scale removability. For the selected reference industrial scenario, the burner was positively tested in industrial furnace with a 30% of hydrogen in volume with no need of hardware modifications. Moderate scale growth was observed, but with no detrimental effect on the scale removability. Moreover, the H-2 addition allows to get CO2 reductions, without any noticeable drawback on other process parameters or product quality for this industrial scenario.