Dynamic Modeling and Simulation of Basic Oxygen Furnace (BOF) Operation

Abstract

Basic oxygen furnaces (BOFs) are widely used to produce steel from hot metal. The process typically has limited automation which leads to sub-optimal operation. Economically optimal operation can be potentially achieved by using a dynamic optimization framework to provide operators the best combination of input trajectories. In this paper, a first-principles based dynamic model for the BOF that can be used within the dynamic optimization routine is described. The model extends a previous work by incorporating a model for slag formation and energy balances. In this new version of the mathematical model, the submodel for the decarburization in the emulsion zone is also modified to account for recent findings, and an algebraic equation for the calculation of the calcium oxide saturation in slag is developed. The dynamic model is then used to simulate the operation of two distinct furnaces. It was found that the prediction accuracy of the developed model is significantly superior to its predecessor and the number of process variables that it is able to predict is also higher.

Evaporation of As and Sn from Liquid Iron: Experiments and a Kinetic Model during Top-Blown Oxygen Steelmaking Process

“…The temperature and C content in the droplets are different from those of the remaining hot metal bath. Those reported in the literature were used in the present study [ 21 , 22 , 23 , 27 , 28 ]. As and Sn evaporate during the steelmaking process.…”

“…Temperature and C contents in various places in liquid iron are shown in Figure 6 . Dashed curves and dotted curves were taken from the available literature [ 22 , 23 , 28 ]. Solid curves in the figures will be explained later ( Section 5.1.5 and Section 5.1.6 ).…”

“…Open circles were taken from Dogan et al [ 21 ]. Using the reported relationship between blowing time t (min) and [pct C] [ 22 , 27 , 32 ], as seen in Figure 8 b (closed circles and a dashed curve), a relationship between and t was estimated: which was also shown in Figure 8 b by a solid curve. As seen in Figure 8 a, the droplets do not eject at low [pct C] (approximately less than 1 pct).…”

“…( b ) [pct C] change reported by Cicutti et al (closed circles) [ 27 , 32 ]. Dashed curve was fitted to these two sets of data [ 22 ]. A solid curve is the estimated residence time as a function of the blowing time.…”

“…First, the evaporation rate of these elements was measured experimentally, and the apparent rate constants were obtained. Second, mass, temperature, and surface area of ejected iron droplets during a top-blown oxygen steelmaking process were estimated by utilizing models available in the literature [ 19 , 20 , 21 , 22 , 23 ]. Those two were coupled to simulate the evaporation rate of the tramp elements during the BOF process.…”