Heat Transfer and Energy Analysis of a Pusher Type Reheating Furnace Using Oxygen Enhanced Air for Combustion

Oxy-fuel firing is more energy efficient and environmental friendly than conventional air-fuel firing and its application for reheating furnaces has begun since 90s. In this study, a computational methodology is presented to predict the steady heat transfer to the billets and temperature distribution in a continuous Pusher type reheating furnace which combustion air is enhanced by oxygen. The furnace is modeled as 2D radiating medium and Weighted Sum of Gray Gases model is used for absorption coefficient. The billets are moved in constant speed through zones of furnace. Radiative heat flux calculated from the radiative heat exchange within the furnace is modeled using the FVM considering the effects of furnace walls and billets. Energy consumption per ton of steel, production rate and thermal efficiency of furnace, and trend of NOx emission in various levels of oxygen enrichment is investigated by comparison with baseline furnace (21% O2 in air).