(222am) Optimal Heating and Energy Management for the Reheating Furnace Using Oxygen Enhanced Combustion

Oxygen enhanced combustion techniques can be applied to reheating furnaces by reducing nitrogen of combustion air, either partially or completely, for reducing gas emissions and improving the thermal efficiency and productivity. However, with the increase of the oxygen concentration, the furnace temperature and the heat transfer characteristic are different from conventional air combustion, and the heating process of billets in the furnace will be affected, which is a challenge to the optimized control of  the reheating furnace.

The optimization of the furnace temperature system is the basis of optimized control． In this paper，the dynamic model and furnace temperature optimization model were established． According to the mathematical model steady quantitatively analyze the heating process influence that change of each billet temperature，the heuristic algorithm rule sets was formed，and the furnace temperature of the reheating furnace using oxygen enhanced combustion was optimal analyzed by the object function under various operation conditions．

Optimal heating and energy management are identified via a constrained, multi-parametric optimization approach. The objective function is the minimization of total process energy consumption (both oxygen-making device and reheating furnace) per ton of steel. The optimal variables are the oxygen concentration and production rate.  Key performance indicators such as temperature uniformity, the discharging target temperature as well as the minimization of steel mass loss and also the minimization of CO2 emissions to the atmosphere are included in the optimality criteria.

Energy consumption per ton of steel, production rate and thermal efficiency of furnace in various levels of oxygen enrichment were investigated by comparing with baseline furnace (21 % of O2 in air). The results showed that the best range of oxygen enrichments was between 21% and 45% by volume, as the higher slope of energy consumption decrease and production increase occurs in this range.