Dynamic Modeling of the Main Blow in Basic Oxygen Steelmaking Using Measured Step Responses

Abstract

In the control and optimization of basic oxygen steelmaking, it is important to have an understanding of the influence of control variables on the process. However, important process variables such as the composition of the steel and slag cannot be measured continuously. The decarburization rate and the accumulation rate of oxygen, which can be derived from the generally measured waste gas flow and composition, are an indication of changes in steel and slag composition. The influence of the control variables on the decarburization rate and the accumulation rate of oxygen can best be determined in the main blow period. In this article, the measured step responses of the decarburization rate and the accumulation rate of oxygen to step changes in the oxygen blowing rate, lance height, and the addition rate of iron ore during the main blow are presented. These measured step responses are subsequently used to develop a dynamic model for the main blow. The model consists of an iron oxide and a carbon balance and an additional equation describing the influence of the lance height and the oxygen blowing rate on the decarburization rate. With this simple dynamic model, the measured step responses can be explained satisfactorily.

The Influence of Sulfur on Dephosphorization Kinetics Between Bloated Metal Droplets and Slag Containing FeO

“…Several researchers have studied aspects of droplet behavior relevant to steelmaking including, decarburization, [1][2][3][4][5][6] droplet generation, [7][8][9][10][11][12][13][14][15][16] size distribution, [17,18] and residence time. [19] Other workers have developed models [20][21][22][23] and conducted plant trials, [24][25][26][27][28] which considered the role of droplets in the overall process kinetics. Previous work in the authors' laboratory [6] showed that droplet swelling, caused by CO formation inside the droplet, increased the droplet residence time in the slag, thereby favoring decarburization.…”

Thermodynamic and Kinetic Model of the Converter Steelmaking Process. Part 1: The Description of the BOF Model

“…For the automation of converter steelmaking, the process models, based on the statistical researches of the industrial data, the dynamic modeling using the measured step responses, the neural‐network models, are widely applied for the prediction of the main end‐blow parameters such as: End‐blow carbon and phosphorus content, and temperature. The fundamentals of all metallurgical processes are thermodynamic and kinetic processes.…”

Comprehensive Model of Oxygen Steelmaking Part 1: Model Development and Validation

“…There have been a number of process models [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] developed to describe the kinetics of oxygen steelmaking process with an emphasis on the evolution of bath temperature, metal and slag chemistry. The details of these models are not available in the open literature and they are generally used for internal research requirements at steel plants.…”