Journal of The Korean Society Combustion ISSN:1226-0959(Print) 2466-2089(Online) 한국연소학회지

Because of increasing demand to utilize the coke oven gas (COG) for hydrogen production, there is a need to replace COG with natural gas (NG) in the steel making industry. In this study, ideal combustion condition and impact on NOx emission were evaluated in a burner to preheat a ladle used for transport of molten iron. Computational fluid dynamics (CFD) were employed to analyze the distribution of temperature and heat flux in the refractories of an existing ladle. Then, different combustion conditions were assessed for the burner introducing NG. It was found that the same thermal condition of the refractories with the reference case can be achieved for NG combustion by reducing the excess air ratio to match the adiabatic flame temperature. A major NOx reduction was expected by the fuel switching because of lower peak temperatures and reduced contribution of NNH mechanism, which agreed with the field data. Increasing the thermal input of the burner led to a linear increase in the wall temperature and decrease in the thermal efficiency while NOx emission remained steady. Further investigations are required to improve the thermal efficiency by utilizing the enthalpy of the hot flue gas.