scholarly journals Splashing Simulation of Liquid Steel Drops during the Ruhrstahl Heraeus Vacuum Process

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1070
Author(s):  
Zhi-jian Zhao ◽  
Min Wang ◽  
Lei Song ◽  
Yan-ping Bao
Keyword(s):  
Pressure Drop ◽  
Liquid Steel ◽  
Industrial Production ◽  
Vacuum Chamber ◽  
Early Stage ◽  
Vacuum Treatment ◽  
Coupling Model ◽  
Liquid Level ◽  
Vacuum Pressure ◽  
Discrete Phase Model

In view of the serious splashing problem in the 120 ton Ruhrstahl Heraeus (RH) refining process of a special steel company, a coupling model of volume of fluid + discrete phase model was established to study the influence of the vacuum pressure drop mode on the RH vacuum splashing. Three different pressure drop modes were simulated, and the splash situation was described by the fluctuation of the liquid level and the velocity field in the vacuum chamber in this model. The model predicted that the most serious splashing situation of liquid drops would happen at the early stage of vacuum treatment, which was consistent with that found in industrial production. The liquid level in the vacuum chamber maintained a low fluctuation at the late stage of the RH vacuum process. The vacuum pressure drop mode was closely relevant with the splashing situation. The splashing of liquid steel can be effectively improved by controlling the vacuum pressure drop mode, and it can be used in the industrial production situation.

Numerical Study on the Removal of Hydrogen and Nitrogen from the Melt of Medium Carbon Steel in Vacuum Tank Degasser

2013 ◽  
Vol 762 ◽  
pp. 253-260 ◽  
Author(s):  
Shan Yu ◽  
Jyrki Miettinen ◽  
Seppo Louhenkilpi
Keyword(s):  
Carbon Steel ◽  
Liquid Steel ◽  
Gas Flow ◽  
Numerical Study ◽  
Vacuum Treatment ◽  
Medium Carbon Steel ◽  
Transfer Coefficients ◽  
Ansys Fluent ◽  
Medium Carbon ◽  
Cell Expression

The steelmaking field has been seeing an increased demand of reducing hydrogen and nitrogen in liquid steel before casting. This is often accomplished by vacuum treatment. This paper focuses on developing a numerical model to investigate the removal of hydrogen and nitrogen from the melt of medium carbon steel in a commercial vacuum tank degasser. An activity coefficient model and the eddy-cell expression are implemented in the ANSYS FLUENT code to compute the activities of related elements and mass transfer coefficients of hydrogen and nitrogen in liquid steel. Several cases are simulated to assess the effect of gas flow rate and initial nitrogen content in liquid steel on degassing process and the calculated results are compared with industrial measured data.

Selective Catalytic Reduction of NOx over Zeolite-Coated Cordierite-Based Ceramic Foams: Water Deactivation

2008 ◽  
Vol 587-588 ◽  
pp. 810-814 ◽  
Author(s):  
Susana Dias ◽  
Fernando A. Costa Oliveira ◽  
C. Henriques ◽  
F.R. Ribeiro ◽  
Carmen M. Rangel ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Early Stage ◽  
Low Pressure ◽  
Membrane Reactors ◽  
Ceramic Foam ◽  
Catalytic Distillation ◽  
Ceramic Foams ◽  
Stage Of Development

The reactors used for Selective Catalytic Reduction (SCR) of NOx require low pressure drop structured catalyst packing. Structured packings, such as ceramic foams, are gaining increasing interest for application in low pressure drop reactors, membrane reactors and catalytic distillation units. In this work, cobalt ion exchanged mordenite (Co-HMOR)-coated cordierite-based foams produced by the replication method were evaluated for catalytic reduction of NOx with methane. The addition of 0.3 wt.% Pd to 2 wt.% Co-HMOR leads to a material that can convert 50 % NOx to N2 at 450 °C in a reaction mixture containing 2000 ppm CH4, 1000 ppm NOx, 5 % O2 and balance helium, at GHSV=17000 h-1. Although in an early stage of development, an efficient coating procedure was explored and different ways of exchange of Co and Pd cations into mordenite (Si/Al=10) were studied. Additions of 2 wt.% fumed silica enhanced adhesion of the zeolite onto the ceramic foam. Pd-exchanged Co-HMOR showed to be very sensitive to steam. A 50 % decrease in NOx conversion to N2 was observed after Pd/Co-HMOR samples were exposed at 450 °C to a reaction mixture containing 2 vol% H2O. Although further research is needed to ascertain the mechanism of this deactivation behaviour, agglomeration of Pd forming PdO particles is envisaged.

Study of the pressure drop in dust scrubber affected by liquid flowability

2019 ◽  
Vol 233 (5) ◽  
pp. 1066-1073 ◽  
Author(s):  
Xiaochuan Li ◽  
Tao Wei ◽  
Xinhao Xu ◽  
Reyna M Knight ◽  
Jiahang Li
Keyword(s):  
Pressure Drop ◽  
Drag Coefficient ◽  
Linear Relationship ◽  
Gas Phase ◽  
Force Balance ◽  
Liquid Level ◽  
Gas Velocity ◽  
Two Phase ◽  
Total Drag ◽  
Quadratic Curve

The complexity of the gas-liquid two-phase flow results in equally complicated pressure drop characteristics for self-excited wet dust scrubbers. In this paper, the pressure drop of the dust scrubber was studied by measuring the total pressure drop R and the differential liquid level Δ H versus the gas velocity v at different initial liquid level b0 values, combined with the liquid flowability. The results showed that the dust scrubber varied its total drag coefficient by changing the differential liquid level Δ H of the liquid-phase and then adjusting the gas-liquid two-phase force balance ahead of and behind the choke. Under the influence of liquid flowability, the throttling strength α exhibited a linear relationship with the gas velocity of the dust scrubber when b0 ≤ 0 mm. The Δ H-v and R- v characteristics of the dust scrubber varied with different values of b0 and v. When b0 > 0, the Δ H-v curve and R- v curve exhibited an explicit quadratic curve relationship. When b0 ≤ 0 mm, the Δ H-v curve and R- v curve exhibited an explicit linear relationship, where the Δ H-v curves can be expressed by a linear equation Δ H = khv+Δ H0, and the gas-phase pressure drop R can be approximately calculated using the differential liquid level Δ H. The liquid flowability can change the choke-sectional to change the total drag coefficient, which reduced in multiple folds with an increase in the gas velocity.

Chapter II. The World Economy

1976 ◽  
Vol 77 ◽  
pp. 33-49
Keyword(s):  
United States ◽  
Industrial Production ◽  
World Economy ◽  
Early Stage ◽  
The United States ◽  
Oecd Countries ◽  
The Third ◽  
The World ◽  
Trading Partners ◽  
To Come

It is now clear that output in the OECD countries rose even faster in the early stage of the recovery than we had previously supposed. Between the third quarter of 1975 and the first quarter of 1976 their aggregate GDP appears to have increased at an annual rate of 7 per cent and their industrial production at 12 per cent. By the second quarter, however, stock movements were probably making a substantially smaller contribution to the expansion of demand. The rate of growth of industrial production has slowed down considerably since the spring and the same is probably true of GDP, particularly in view of the effects of the drought on European agricultural output. By the second half of next year we expect the deceleration to become more pronounced in the major countries, particularly the United States. The smaller countries have, however, been lagging behind their bigger trading partners in the recent cycle and their phase of rapid recovery is probably yet to come. In all we expect OECD countries' aggregate GDP to increase in volume by 5½–6 per cent this year and 5 per cent in 1977.

Design and Fabrication of PDMS Microchamber for Fast Reaction Assays in Biosensing Application

2013 ◽  
Vol 795 ◽  
pp. 329-333 ◽  
Author(s):  
Tijjani Adam ◽  
U. Hashim ◽  
M. Wesam Al-Mufti
Keyword(s):  
Pressure Drop ◽  
Soft Lithography ◽  
Early Stage ◽  
Reaction Diffusion ◽  
Cost Effective ◽  
Open Circuit ◽  
Sensing Element ◽  
Fast Reaction ◽  
Flow Phenomena ◽  
Drop Flow

A simple design of a microchamber for use in reacting assays with limited sample availability has been proposed, analyzed using COMSOL 3.5 Multiphysics simulation and fabricated using soft-lithography technique . The design is based on differential pressure drop flow using capillary effect concept which has facilitated a number of interesting flow phenomena in micro-domains. For an average pressure drop of about 100/m in the setup, flow rates of bout 0.5 to 0.8 μl/s were obtained. The component a microchamber, three designs were tested (50, 70, 90 microns in width) to give a continuous open circuit flow. The system was designed and fabricated for continuous flow across sensing element where there is a requirement for low residence time due to fast reaction/diffusion rates.Also in this paper, is a sensitive and selective, also rapid, reliable, cost-effective, and suitable for in situ analysis polymer biosensor for new bio molecular approach for cancer and cancer related diseases detection at the early stage is demonstrated.

Improvement of the Crystallinity of La2CuO4 Nanoparticles Using the Vacuum Treatment

2021 ◽  
Vol 1028 ◽  
pp. 44-49
Author(s):  
Anita Eka Putri ◽  
Suci Winarsih ◽  
Budhy Kurniawan ◽  
Dicky Rezky Munazat ◽  
Dhawud Sabilur Razaq ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Vacuum Treatment ◽  
Vacuum Pressure ◽  
Morphological Properties ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Xrd Patterns

Nanoparticles of La2CuO4 (LCO) with different particles and crystallite size have been synthesized by the sol-gel method. The samples have been sintered at 600, 650, and 700°C. The sintering process have been performed in atmospheric pressure and vacuum pressure. The structural and morphological properties of the samples have been investigated by the X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM). The XRD patterns of the samples have shown that all samples crystallize in orthorhombic structure with Bmab space group. Additionally, Rietveld refinement process have shown that higher sintering temperature, as well sintering process under vacuum pressure, can improve both phase purity and the crystallinity of the samples. SEM and TEM results have also shown that higher sintering temperature results in a sample with larger particle size.

Optimal Design of Power Transfer Unit Oil Seal Considering Pressure Drop Generated during Water-Way Driving

2017 ◽  
Vol 739 ◽  
pp. 247-251
Author(s):  
Tae Hyung Kim ◽  
Chang Gon Kim ◽  
Eun Min Park ◽  
Sok Choi ◽  
Bo Ram Lee
Keyword(s):  
Optimal Design ◽  
Pressure Drop ◽  
Friction Force ◽  
Vacuum Pressure ◽  
Power Transfer ◽  
Water Intrusion ◽  
Oil Leakage ◽  
Transfer Unit ◽  
Critical Problems

This study investigated the pressure drop generated in the power transfer unit (PTU). During water-way driving, this pressure drop could open the lips of an oil seal and caused critical problems, such as water intrusion into or oil leakage out of the PTU. Optimal design of oil seal shape was proposed in order to prevent the unexpected failure of oil seal. As the result of the test to check the effects of the vacuum pressure, it was found that outside water was flowed into inside at - 0.4 bar for dust lip without any interference, whereas, there was no intrusion of outside weater through the seal with interferences of dust lips even at - 0.8 bar. But the seal with interferences of dust lips had 30~40 % higher than that without interference because the interference of dust lip with shaft made friction force increased at the interface between rubber and shaft.

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