Abstract:The flow characteristics and postcombustion behavior of a single‐flow postcombustion (PC) oxygen lance are of paramount significance to optimal design and operation of the lance but not well understood, and there is also no well‐known design criterion for the optimization of the single‐flow PC lance. Herein, the design criteria of a single‐flow PC lance are first proposed. Then, a 3D fluid model is established combined with a 120 t top‐blown converter. The influences of the key parameters of secondary nozzles … Show more
“…Meanwhile, as mentioned earlier, the velocity and dynamic pressure of PC oxygen lance are greater than that of conventional oxygen lance in the radial and axial directions, and it has a more significant impact on performance. In the smelting process, good impact performance and furnace conditions can accelerate the decarburization reaction, leading to smelting steel meeting the requirements of steel production in advance [25,37]. The potential values of PC oxygen lance are reflected by increasing oxygen supply intensity, shortening the smelting cycle and improving oxygen utilization rate. Figure 13. Blowing time (a) and actual oxygen consumption (b) of a single heat of the two oxygen lances.…”
“…Ke et al [21] applied the singleflow PC lance to 30-ton combined blowing converter and found that it had the advantages of rapid slagging, less splashing and smooth blowing. The authors [22][23][24][25] first proposed the design criteria of a single-flow PC oxygen lance and studied the influences of different secondary nozzle parameters on jet characteristics and PC behaviour by numerical simulation; then the optimized PC oxygen lance was applied to the top-blown converter and its metallurgical effects were compared with that of the conventional oxygen lance. Currently, there are few reports on the comparison of flow field characteristics between the single-flow PC oxygen lance and the conventional lance at steelmaking temperature as well as their industrial application.…”
Flow field characteristics of conventional four-hole oxygen lance and single-flow post-combustion (PC) oxygen lance at steelmaking temperature are studied by numerical simulation, and the industrial trials are carried out in the 120 t top-blown converter to evaluate their metallurgical effects. The simulation results indicate that with the increase of ambient temperature, the potential core length of oxygen jet, jet velocity and radial width (jet diameter) increase. And the jet characteristics of PC oxygen lance are better than those of conventional lance in the radial and axial directions. The industrial trials show that, compared with the conventional lance, using the PC oxygen lance can shorten blowing time by 93 s, reduce actual oxygen consumption by 3.56 m 3 t −1 and increase dephosphorization rate by 1.67%. Meanwhile, PC oxygen lance is better for slagging and solves the problem of splashing or drying caused by increasing the oxygen flow rate of the conventional lance.
“…Meanwhile, as mentioned earlier, the velocity and dynamic pressure of PC oxygen lance are greater than that of conventional oxygen lance in the radial and axial directions, and it has a more significant impact on performance. In the smelting process, good impact performance and furnace conditions can accelerate the decarburization reaction, leading to smelting steel meeting the requirements of steel production in advance [25,37]. The potential values of PC oxygen lance are reflected by increasing oxygen supply intensity, shortening the smelting cycle and improving oxygen utilization rate. Figure 13. Blowing time (a) and actual oxygen consumption (b) of a single heat of the two oxygen lances.…”
“…Ke et al [21] applied the singleflow PC lance to 30-ton combined blowing converter and found that it had the advantages of rapid slagging, less splashing and smooth blowing. The authors [22][23][24][25] first proposed the design criteria of a single-flow PC oxygen lance and studied the influences of different secondary nozzle parameters on jet characteristics and PC behaviour by numerical simulation; then the optimized PC oxygen lance was applied to the top-blown converter and its metallurgical effects were compared with that of the conventional oxygen lance. Currently, there are few reports on the comparison of flow field characteristics between the single-flow PC oxygen lance and the conventional lance at steelmaking temperature as well as their industrial application.…”
Flow field characteristics of conventional four-hole oxygen lance and single-flow post-combustion (PC) oxygen lance at steelmaking temperature are studied by numerical simulation, and the industrial trials are carried out in the 120 t top-blown converter to evaluate their metallurgical effects. The simulation results indicate that with the increase of ambient temperature, the potential core length of oxygen jet, jet velocity and radial width (jet diameter) increase. And the jet characteristics of PC oxygen lance are better than those of conventional lance in the radial and axial directions. The industrial trials show that, compared with the conventional lance, using the PC oxygen lance can shorten blowing time by 93 s, reduce actual oxygen consumption by 3.56 m 3 t −1 and increase dephosphorization rate by 1.67%. Meanwhile, PC oxygen lance is better for slagging and solves the problem of splashing or drying caused by increasing the oxygen flow rate of the conventional lance.
“…According to the symmetry of converter, the 1/5 converter shown in Figure 2 was selected for simulation calculation. As shown in the figure, the stagnation pressure of all nozzle was 0.9 MPa and inlet oxygen temperature was 300 K; the gauge pressure of the outlet was 0.098 MPa and ambient temperature was 1773 K. [34] The pressure inlet was selected as the inlet boundary. The pressure outlet was selected as the outlet boundary and the rest set as wall surface.…”
Section: Computational Model and Boundary Conditionsmentioning
confidence: 99%
“…In order to improve scrap ratio, the postcombustion oxygen lance is proposed as a clean heat compensation technology with no pollution, [31][32][33][34] which is characterized by the opening of a certain number of secondary holes on the traditional oxygen lance, thus improving the post combustion area in the space below the oxygen lance. The postcombustion oxygen lance is divided into dual-flow and single-flow channels.…”
Section: Introductionmentioning
confidence: 99%
“…The main jet of the postcombustion oxygen lance had a larger offset from the geometric centerline of the main hole than the normal oxygen lance. The authors of previous studies [34] analyzed the influence of different process parameters of single-flow secondary combustion oxygen lance on jet coalescence for 120 t converter and carried out an industrial test study. As a matter of fact, the jet characteristics of the oxygen lance with an even number of peripheral main holes added to the secondary hole have been studied, but the study of the jet characteristics of the oxygen lance with an odd number of peripheral main holes added to the secondary hole is less.…”
The supersonic jet characteristics of the oxygen lance nozzle play an important role in converter melting. However, limited studies have investigated the different nozzle arrangements to improve the jet characteristics. This study uses FLUENT to establish a compressible nonisothermal computational fluid model with a 250 t converter as the object, and the model first validates and then discusses the effects of the center hole and postcombustion (PC) oxygen lance secondary hole on the aggregation behavior and impact area of the oxygen jet based on the conventional five‐hole oxygen lance. The study shows that, at the same distance, the influence of the peripheral jet offset degree from small to large is secondary hole–center hole–secondary hole with center hole. At the lance height of 1900 mm, compared to the traditional five‐hole oxygen lance offset theoretical axial centerline distance is 1.98, 2.31, and 3.20 times. The larger the jet migration degree of the peripheral hole, the smaller is the velocity of the peripheral jet. The presence of center hole, secondary hole, and center hole with secondary hole encloses 1.04, 1.09, and 1.47 times the area enclosed by the conventional five‐hole oxygen lance at 150 m s−1 isovelocity line, respectively.
The oxygen lance jet plays a crucial role in the steelmaking process in a converter. The quantitative relationship between the operating parameters of the oxygen lance and the volume of the impact cavity is established for the first time, and the leading factors affecting the volume of the impact cavity are identified through correlation analysis. This article examines the influence of operating pressure and lance position on the impact cavity of a 170 t converter in a nonisothermal environment through numerical analysis. The results show that the ambient temperature in the converter presents a layered phenomenon. The temperature near the free surface ranges from 1550 to 1600 K and then gradually decreases to 900 K at the oxygen lance outlet. When the ratio of the operating pressure to the design working pressure is less than 1.0 or greater than 1.3, the cavity volume is significantly affected by the operating pressure but has less of an impact when the ratio is between 1.0 and 1.3. The cavity volume shows a linear relationship with the oxygen lance position. Moreover, the oxygen lance position has a greater influence on the cavity volume and velocity distribution than do the operating pressure.
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