Effect of Main Gas Composition on Flow Field Characteristics of Supersonic Coherent Jets with CO₂ and O₂ Mixed Injection (COMI) at Steelmaking Temperature

Abstract

As an efficient oxygen supplying technology, coherent jets are widely applied in electric arc furnace (EAF) steelmaking processes to strengthen chemical energy input, speed up smelting rhythm and promote the uniformity of molten bath temperature and compositions. Recently, the supersonic coherent jets with CO 2 and O 2 mixed injection (COMI) was proposed and through industrial experiments, it can be found that the supersonic coherent jets with COMI showed remarkable advantages in reducing the dust production during EAF steelmaking. In this study, based on the eddy dissipation concept (EDC) model with the detailed chemical kinetic mechanisms (GRI-Mech 3.0), a computational fluid dynamics (CFD) model of supersonic coherent jets with COMI was built. Compared with one-step combustion reaction, GRI-Mech 3.0 consists of 325 elementary reactions with 53 components and can predict more accurate results. The numerical simulation results were validated by the combustion experiment data. The jet behavior and the fluid flow characteristics of supersonic coherent jets with COMI at steelmaking temperature 1 700 K was studied and the results show that the chemical effect of CO 2 significantly weakens the shrouding combustion reactions of CH 4 and the relative importance of the chemical effect of CO 2 increases with CO 2 concentration increasing. The potential core length of supersonic coherent jets decreases with the volume fraction of CO 2 increasing. Moreover, it also can be found that the potential core length of supersonic coherent jets can be prolonged with higher ambient temperature.

Effect of Furnace Gas Composition on Characteristics of Supersonic Oxygen Jets in the Converter Steelmaking Process

“…Figure 5 and Figure 6 show the axial velocity and axial total pressure distribution of the supersonic oxygen jet in the numerical simulation and combustion experiment of Schemes 1 and 2 [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. Table 4 and Table 5 shows the average and standard deviation of the axial velocity and the axial total pressure at the monitoring point, respectively.…”

“…Liu et al [ 14 ] used a cylindrical combustion device to study the influence of the lance structure on electric furnace steelmaking. During the high temperature experiment, they used pitot tubes and thermocouples to measure pressure and temperature, respectively [ 16 , 17 , 18 , 19 , 20 ]. Therefore, this article used Pitot tubes and thermocouples to measure pressure and temperature.…”

“…At the beginning of the experiment, the combustion furnace was heated to the required temperature with the burner, and at the same time, the ambient gas was added to the furnace from points K and L. After the desired temperature was reached, the burner was removed, and a lance with a water cooling system was installed in its place. Then, the lance was supplied with oxygen and the experimental data was measured [ 16 , 17 , 18 , 19 , 20 ]. In this article, the temperatures at points A, B, C, D, and E were 1873 ± 16 K, 1873 ± 14 K, 1873 ± 10 K, 1873 ± 24 K, and 1873 ± 19 K, respectively.…”

Fluid Dynamics Analysis of O₂–CaO Jet with a Shrouding Flame for EAF Steelmaking

“…Where, C ξ is a volume fraction constant and its value is 2.138; C t is a time scale constant and its value is 0.408. Based on the previous studies, 33,34) the chemical kinetic mechanism of CH 4 combustion with oxygen plays an important role in the accuracy of the numerical results. Hence, the CH 4 -O 2 combustion reaction mechanism adopted in the present study is the detailed chemical kinetic mechanisms (GRI-Mech 3.0), which consists of 325 elementary reactions with 53 components.…”

Development and Application of Converter COMI-B Technology: A New Way of CO₂ Utilization

“…Researchers in the metallurgical field have conducted extensive research on converter top and bottom combined blowing oxygen, including the optimization of high efficiency oxygen supply of converter oxygen lance, converter bottom blowing layout and process optimization, etc., but there is limited research on the industrial application of converter top and bottom blowing CO2 technology (COMI-B). One of the main research directions of the author of this study has been the application of CO2 resources in converter steelmaking process for many years [33][34][35][36][37][38] . This study focused on experimental research on the application of COMI-B technology and converter smelting, and long-term industrial tests and applications were conducted.…”