Modeling the Effect of Plug Positions and Ladle Aspect Ratio on Hydrogen Removal in the Vacuum Arc Degasser

Abstract

The rate of hydrogen removal from molten steel in a vacuum arc degasser (VAD) is simulated using a three‐phase (slag‐argon‐steel) Eulerian model. The time required to degas a 100 tonne melt from 5 to 1.5 ppm is predicted for a series of ladle aspect ratios and plug layouts. Compared to an axisymmetric single plug system, the degassing time can be reduced by 36% with the use of three equiangular plugs. Increasing the aspect ratio (AR) of the melt from 0.8–1.2 leads to an improvement in degassing performance, followed by a reduction in performance between AR = 1.2–1.6. A radial plug position of 0.5R is optimal for achieving low hydrogen levels in the melt. Reducing the inter‐plug angle from θ = 180° (for double plug) and θ = 120° (for triple plug) to θ = 45° further reduces this time by 18 and 3.8%, respectively. The fastest rate of hydrogen removal is obtained through the use of three plugs at positioned at an angle of θ = 45° and plug radial position of 0.5R.

A Parametric Study on the Effects of Process Conditions on Dehydrogenation, Wall Shear and Slag Entrainment in the Vacuum Arc Degasser Using Mathematical Modelling

“…This design was found to produce optimal hydrogen removal rates in a previous study by the authors 28) in comparison to single and double plug designs. Based upon this standard ladle design, the purpose of the current study is to investigate the influence of VAD process conditions (argon flowrate and vacuum pressure) on hydrogen removal.…”

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.…”

“…Yu et al [13,14] simulated hydrogen and nitrogen degassing in the vacuum tank degasser by combining a Eulerian-Eulerian, argon-steel, two-fluid model with thermodynamics. Recently, Karouni et al [15,16] developed a mathematical model accounting for hydrogen degassing in a vacuum arc degasser using a three-phase Eulerian method and a discrete population balance model, and they investigated the effect of plug positions and the ladle aspect ratio on hydrogen removal. More recently, Chen et al [18,19] numerically studied the tracers' transport process in a water model of a vacuum refining unit corresponding to a single-snorkel refining furnace, focusing on the fluid dynamics for degassing.…”

The Degassing Laws for Railway Wheel Steel in a Vacuum Tank Degasser

“…As it is known, vacuum results are influenced not only by technological parameters of processing, but also by a large number of technological and organizational factors [2][3][4][5][10][11][12][13][14][15][16][17][18][19][20]. Therefore, despite a large number of studies on the effects of hydrogen and nitrogen in vacuuming [10][11][12][13][14][15][16][17][18][19][20], the study of the results of steel degassing in specific production conditions allows us to obtain new patterns and improve the production technology.…”