Design and Scale-up of a Hydrogen Oxy-fuel Burner for High-temperature Industrial Processes

The present study investigates the design and scale-up of a pure hydrogen oxy-fuel combustion burner for industrial applications. In recent years, this technology has garnered attention as an effective approach to the decarbonisation of high-temperature industrial processes. Replacing air with oxygen in combustion processes significantly reduces nitrogen oxides emissions and leads to sustainable energy use. A laboratory-scale burner was designed with inlet nozzle dimensions adapted to the specific properties of hydrogen and oxygen as fuel and oxidant, respectively. Implementing oxy-fuel combustion requires addressing several technical issues to prevent the burner wall from overheating and to ensure a stable flame. An infrared camera was used to characterise the performance and operating conditions of the laboratory-scale burner in the range of 2.5–30 kW. The 10 kW baseline case was analysed numerically and validated experimentally using thermocouples. This revealed stable lifted flames with maximum temperatures of 2800 K and a flame length of 0.15 m. A key challenge in engineering is transferring results from laboratory-scale to large-scale industrial applications. Once validated, the prototype design was scaled up numerically from 10 kW to 1 MW, investigating the feasibility of different scaling criteria. The impact of these criteria on flame characteristics, mixing patterns, and the volumetric distribution of the reaction zone was then assessed. The constant velocity criterion yielded the lowest pressure drops, although it also resulted in longer flame lengths. In contrast, the constant residence time criterion generated the highest pressure drops. The increased velocities associated with this criterion enhanced mixing, leading to shorter flame lengths, as noted in the cases of 200 kW, decreasing from 0.98 m under constant velocity criterion to 0.46 m. The intermediate criteria demonstrated a feasible alternative for scaling up the burner by effectively balancing flame length, mixing rate, and pressure losses. Nevertheless, all criteria enabled the burner to sustain high combustion efficiency. Overall, this investigation provides valuable insight into the potential of hydrogen oxy-fuel combustion technology to reduce carbon emissions in high-temperature processes.