Study on dehydrogenation behaviour of molten steel in single snorkel refining furnace (SSRF) by a mathematical model

Abstract

A mathematical model of an industrial Single Snorkel Refining Furnace (SSRF) has been developed to investigate dehydrogenation behaviour in the vacuum refining process. Dehydrogenation reactions were considered to take place at three sites: Ar bubble surface, bath surface, and the bulk steel. The effects of Ar bubble behaviour and H2 heterogeneous nucleation behaviour of the bulk steel on dehydrogenation were taken into account specifically. The simulation results are in good agreement with the measured industrial data. Using the model, the dehydrogenation rate at different sites and its contribution to total dehydrogenation value were evaluated in detail. The results indicated that bulk steel dehydrogenation occurred only the high concentration range, while the other two reactions participated in the whole refining process. In addition, the effect of argon flow rate on the dehydrogenation rate was also obtained and the reasonable range of argon flow rate for SSRF treatment has been recommended.

Efficiently Removing Hydrogen of H-Supersaturated Liquid Steel in the Vacuum Degasser with Various Gas Injection Modes

“…In the steel industry, the hydrogen degassing from liquid steel is usually achieved in an exclusive vacuum-degassing apparatus, such as VD or Ruhrstahl-Heraeus (RH), in which liquid steel is subjected to a combination of low pressure and argon-purging, and as a result, the dissolved hydrogen can be considerably reduced. In this direction, a great number of studies [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] have been performed to reveal the dehydrogenation behavior of liquid steel based on the thermodynamics and kinetics related to hydrogen removal in an industrial RH or VD by employing an industrial test or Computational Fluid Dynamics techniques. Steneholm et al [11] calculated the removal rates of sulfur, hydrogen, and nitrogen by collecting slag and steel samples before and after the vacuum treatment.…”

“…Steneholm et al [11] calculated the removal rates of sulfur, hydrogen, and nitrogen by collecting slag and steel samples before and after the vacuum treatment. Zhang et al [12] developed a mathematical model of an industrial single-snorkel refining furnace to reveal the dehydrogenation behavior in the vacuum refining process, by considering three dehydrogenation reaction sites, including the Ar bubble surface, the bath surface, and the bulk steel. The effect of the argon flow rate on the dehydrogenation rate was studied, and a reasonable range of the argon flow rate for the SSRF treatment was recommended by the authors.…”

Analysis of fluid flow characteristics of RH reactor with different bottom-blowing arrangements

“…Ar and other driving gases are blown in from a plurality of nozzles distributed in the up-snorkel and expand under high temperature and low pressure, resulting in the reduction of the density of the mixture in the upsnorkel and the circulation of molten steel between the vacuum chamber and the ladle [1,4,16]. The refining effect of RH reactor is generally improved by increasing the circulation speed of molten steel between vacuum chamber and ladle and reducing the time for melt to reach uniform mixing, that is, circulation flow rate and mixing time [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”