A review on advancement in strategies for low-NOx hydrogen combustion with micromix technology

Abstract Micromix combustion technology emerges as a promising solution to address challenges in achieving clean combustion, particularly for hydrogen utilisation. This review provides a critical analysis for the potential of micromixing by delving into its core principles, diverse applications and the factors influencing its performance. The paper focuses on injector design, flame stabilisation and NOx mitigation strategies within the micromixing framework. Key findings include innovative burner designs, optimised air distribution techniques and the crucial role of fuel properties, especially for hydrogen combustion. The review highlights significant reductions in NOx emissions achieved through micromix combustion technology. For instance, NOx emissions were lowered to 2.2 ppm at φ = 0.4, representing a 45% improvement compared to conventional design configurations. Furthermore, a reduction of 40% in NOx emissions compared to standard configurations was observed at an equivalence ratio of 0.65. The study also compares NOx emissions between hydrogen and its blended fuels, showing lower emissions for methane. By highlighting the importance of optimising fuel mixture formation and flame stability for various operating conditions, this review underscores the significance of micromix combustion for advancing sustainable combustion technologies with low NOx emissions and reduced chance of flashback in hydrogen combustion.