Modeling Study of Nitrogen Removal from the Vacuum Tank Degasser

Yu, Sophia; Miettinen, Jyrki; Louhenkilpi, Seppo

doi:10.1002/srin.201300262

Cited by 11 publications

(4 citation statements)

References 25 publications

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“…The CFD model has been tested with a set of examples and it has proven to be capable of capturing the main features of multiphase flows in the VTDs and of predicting final [H] or [N] content by comparisons with some industrial data. [21,22,34] In this paper, the convergence criteria of all simulations are 10 À3 for mass, momentum, and turbulence equations and 10 À6 for species equations. A base case is firstly simulated to demonstrate the integrated model.…”

Section: Cfd Resultsmentioning

confidence: 99%

“…[14] Some related experiments on a laboratory scale have been conducted using a constant amount of surfaceactive elements and the results showed that the denitrogenation can be described as a second-order reaction. [8,15,16] The effect of some alloying elements on nitrogen removal behavior has also been examined [17][18][19][20][22][23][24] and the results revealed that the elements such as titanium (Ti), zirconium (Zr), vanadium (V), manganese (Mn), and chromium (Cr), which have stronger affinity with nitrogen than iron, would enhance the nitrogen dissociation rate (the reaction rate for the reverse reaction of nitrogen desorption), whereas the elements such as aluminum (Al), silicon (Si), boron (B), (copper) Cu, wolfram (W), and tin (Sn) having stronger repulsive force against nitrogen would retard the dissociation rate.…”

Section: Introductionmentioning

confidence: 99%

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Mathematical Modeling of Nitrogen Removal from the Vacuum Tank Degasser

Miettinen

Shao

et al. 2014

steel research int.

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The removal of nitrogen from an industrial vacuum tank degasser depends on a series of operational parameters, steel composition, and contents of surface-active elements in liquid steel, e.g., oxygen and sulfur. The effect of some specific elements on nitrogen removal in the vacuum degasser has been (well) examined. Still, it is quite challenging to assess the overall effect of the whole steel composition on the process. The focus of the present work was to predict nitrogen removal from the vacuum degasser specially taking into account the multi-component effect of steel composition. An integrated computational fluid dynamics (CFD) model for simulating nitrogen (and hydrogen) removal in industrial vacuum tank degassers was therefore developed based on theories and methods that are relatively separate in the literature. In order to include the multi-component effect, the model is coupled with an in-house thermodynamics code that can be used to determine the activity coefficient of nitrogen, oxygen, or sulfur as a function of steel composition and temperature. The code was verified by comparing the calculated activity coefficients against experimental measurements from various sources. Efforts were also put into developing an on-line use concept to control the nitrogen removal. The gas plume, flow field, and evolutions of nitrogen and hydrogen during vacuum treatment were predicted and the on-line concept was demonstrated by presenting two operating diagrams. The results showed that the final nitrogen content decreases with an increase in the chemical reaction rate constant and a decrease in the initial nitrogen content. By contrary, the final nitrogen content increases with a decrease in the chemical reaction rate constant and an increase in the initial nitrogen content. Finally, the operating diagrams were validated by industrial data and observations.

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Section: Cfd Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mathematical Modeling of Nitrogen Removal from the Vacuum Tank Degasser

Miettinen

Shao

et al. 2014

steel research int.

Self Cite

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“…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.…”

Section: The Overview Of the Problemmentioning

confidence: 99%

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

Смирнова

Eliseeva

Shapovalov

2021

DDF

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The research presents the results of data analysis on degassing of wheel grades of steels in a tank degasser with a capacity of 120 tons, operated at the JSC “Ural Steel”. The volume of the analyzed sample included 754 steels for railway wheels (steel grades “2” and “T” according to State standard GOST 10791-2011) weighing more than 80 thousand tons received in November-December 2019.It was established that in order to guarantee the production of hydrogen content of less than 1.5 ppm and nitrogen before 0.007%, it is necessary to carry out vacuum treatment of metal with overheating of 110-130°C at the residual pressure of up to 3 mbar for 20-25 minutes and argon flow rate of at least 0.05 m3/ton. The regression equation was obtained, which allows to predict the results of degassing, as well as select the values of vacuum treatment parameters in order to achieve a given content of dissolved gases - hydrogen and nitrogen.

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“…Based on previous work on the E-E model, the simultaneous reaction model (SRM) coded by these researchers was added to investigate the metal-slag reactions. In contrast, Yu et al [118][119][120][121][122] mainly focused on investigating the dehydrogenation and denitrogenation behaviors in an industrial vacuum tank degasser with different operating conditions. A recent work by Li et al [39] used the PBM to calculate the bubble size distribution affected by the coalescence and breakage in the plume.…”

Section: E-e Modelmentioning

confidence: 99%

A Review of Physical and Numerical Approaches for the Study of Gas Stirring in Ladle Metallurgy

Liu

Ersson

et al. 2018

Metall Mater Trans B

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This article presents a review of the research into gas stirring in ladle metallurgy carried out over the past few decades. Herein, the physical modeling experiments are divided into four major areas: (1) mixing and homogenization in the ladle; (2) gas bubble formation, transformation, and interactions in the plume zone; (3) inclusion behavior at the steel-slag interface and in the molten steel; and (4) open eye formation. Several industrial trials have also been carried out to optimize gas stirring and open eye formation. Approaches for selecting criteria for scaling to guarantee flow similarity between industrial trials and physical modeling experiments are discussed. To describe the bubble behavior and two-phase plume structure, four main mathematical models have been used in different research fields: (1) the quasi-single-phase model, (2) the volume of fluid (VOF) model, (3) the Eulerian multiphase (E-E) model, and (4) the Eulerian-Lagrangian (E-L) model. In recent years, the E-E model has been used to predict gas stirring conditions in the ladle, and specific models in commercial packages, as well as research codes, have been developed gradually to describe the complex physical and chemical phenomena. Furthermore, the coupling of turbulence models with multiphase models is also discussed. For physical modeling, some general empirical rules have not been analyzed sufficiently. Based on a comparison with the available experimental results, it is found that the mathematical models focusing on the mass transfer phenomenon and inclusion behaviors at the steel-slag interface, vacuum degassing at the gas-liquid interface, dissolution rate of the solid alloy at the liquid-solid interface, and the combination of fluid dynamics and thermodynamics need to be improved further. To describe industrial conditions using mathematical methods and improve numerical modeling, the results of physical modeling experiments and industrial trials must offer satisfactory validations for the improvement of numerical modeling.

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Modeling Study of Nitrogen Removal from the Vacuum Tank Degasser

Cited by 11 publications

References 25 publications

Mathematical Modeling of Nitrogen Removal from the Vacuum Tank Degasser

Mathematical Modeling of Nitrogen Removal from the Vacuum Tank Degasser

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

A Review of Physical and Numerical Approaches for the Study of Gas Stirring in Ladle Metallurgy

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