Experimental investigation on the oxidation process and mechanism of steel billet under oxygen-enriched combustion atmosphere

Abstract

ABSTRACT Oxygen-enriched combustion is a promising next-generation combustion technology for the metallurgy industry, allowing net efficiency improvement compared to traditional combustion technology. In this paper, an experimental investigation of the Q235 billet oxidation process for oxygen-enriched combustion, based on a thermogravimetric furnace, is carried out to comprehend the scaling kinetic reheat by oxygen-enriched combustion. The formation of iron oxide scale under different temperatures (800–1200°C) and atmospheric combustion conditions was investigated by an isothermal kinetic experiment to simulate an oxygen-enriched combustion atmosphere (21–40%O2). This experiment observed the effects of heating time, surface temperature, combustion oxygen content, and oxidizing gas composition in the flue gas (H2O, CO2) on weight gain of billet oxidation. Conducted investigations demonstrate that the surface temperature of the billet and the oxygen content of the combustion is positively related to the oxidation rate. Temperature is the primary factor affecting the oxidation of billet. The oxide scales gaining weight in the component of oxygen-enriched combustion flue gas, O2, H2O, and CO2 are 26, 62, and 39 (mg/cm2), respectively. Although oxygen oxidation is the most vital factor among the flue gas, the water vapor is the dominant factor in the oxidation degree of the billet as its highest content. Moreover, the dynamic curve under different atmosphere and temperature conditions was investigated. Kinetic analysis shows that the billet oxidation process with oxygen-enriched combustion is closer to the SCM model.