Influence of nozzle design parameters on exhaust gas characteristics in practical-scale flameless hydrogen combustion. (8th June 2022)

• Record Type: Journal Article
• Authors: Kikuchi, Kenta; Motegi, Toru; Hori, Tsukasa; Akamatsu, Fumiteru
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 49(2022)
• Page Start: 21287
• Page End: 21297
• Publication Date: 2022-06-08
• Subjects: NOx -- Hydrogen -- Flameless combustion -- MILD combustion -- Fuel direct injection -- Burner; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.04.230
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Considering the trend toward decarbonization, hydrogen is expected to be used as a fuel in industrial furnace burners. One of the challenges in using hydrogen as a fuel is the increase in thermal-NOx emission compared to hydrocarbon fuel owing to its high flame temperature. This study experimentally evaluated the combustion characteristics of flameless combustion, which is a low-NOx combustion technology, with hydrogen as a fuel in a practical-scale experimental furnace as well as the effect of nozzle design parameters on the combustion characteristics. Through comparative tests with city gas by considering parameters, such as the fuel gas velocity, combustion air velocity, and air nozzle pitch, the low-NOx effect of flameless combustion was confirmed in hydrogen combustion with appropriate nozzle design parameters. The optimal nozzle design parameters to achieve this effect differ from those for city gas, and the design guidelines are summarized. Highlights: NOx emissions from hydrogen combustion in industrial furnaces could be reduced. More than 80% reduction of NOx emission in hydrogen combustion was achieved. The optimal nozzle design that maximizes NOx reduction depends on the fuel type. Higher fuel flow velocity is required for hydrogen combustion. The optimum nozzle design guidelines for practical use were summarized.