Effect of Gas Bottom Blowing Conditions on Mixing of Molten Iron inside an Ironmaking Smelter

Abstract

To aid efficient use of the gas flow rate for a smelting reduction furnace, this study investigates the effect of gas bottom blowing and stirring on the mixing time of the molten iron phase. In this study, transparent acrylic is used to construct a water model, which is 60% as big as the original experimental melting reduction furnace of the China Steel Corporation. The mixing time of the molten iron phase in the water model is measured by using gas bottom blowing and changing the number of tuyeres (from three to five), the tuyere placement, the tuyere size (6.0-15.0 mm), and the gas flow rate per tuyere (80-120 NL/min).The mixing trials adopt KCl as an indicator and use water filtrated using reverse osmosis (RO) in place of liquid iron to investigate the effect of gas bottom blowing conditions on mixing of the molten iron phase. The experimental results indicate that in the cases of four tuyeres in the square-corner and triangle-corner-center placements, 10.0 mm tuyeres yield the shortest mixing time (and thus the best mixing effect) under different total gas flow rates. In the case of five tuyeres in the square-corner-center placement, 10.0 mm tuyeres also have the shortest mixing time under total gas flow rates of 400 NL/min and 500 NL/min. However, 12.5 mm tuyeres have the shortest mixing time under a total gas flow rate of 600 NL/min. In addition, in the case of three tuyeres in the triangle-corner placement, 12.5 mm tuyeres have the shortest mixing time under different total gas flow rates. When the gas flow rate per tuyere is 80 NL/min, the fewer the tuyeres, the shorter the mixing time. Depending on tuyere placement, some of the energy injected by the gas may be counteracted. For example, when a bottom-blowing tuyere exists in the center, the gas injection from that tuyere may be counteracted by that of adjacent tuyeres such that energy dissipates. In contrast, a tuyere placement without a center tuyere may yield better mixing effects. In this study, the best combination for mixing in the liquid phase is four 10.0 mm tuyeres in the square-corner placement and a total gas flow rate of 480 NL/min.

Mixing Phenomena in a Bottom Blown Copper Smelter: A Water Model Study

“…It is noted that the function of bottom blowing in copper smelter is different from steelmaking vessels. [23][24][25] In steelmaking, a combination of top oxygen lance blowing and bottom argon or nitrogen blowing/stirring is widely applied. The purpose of bottom blowing is to supplement the limited stirring created by top oxygen lance.…”

Modelamento Da Formação Do “Olho” E Comportamento De Misturamento Em Panelas De Aciaria

“…Os resultados experimentais indicam ainda que, para as condições operacionais investigadas, a mudança de um plugue poroso excêntrico para dois plugues porosos excêntricos de mesmos diâmetros incorreu em decremento do tempo de misturamento. Este comportamento, por sua, vez, foi observado por Mandal et al [6] e Su et al [10], quando de altas vazões de borbulhamento do gás inerte. Contudo, Zhu et al [5] salientam que um arranjo inadequado do sistema de borbulhamento pode ocasionar o aumento do tempo de misturamento do aço na panela.…”