Effects of Top Layer, Nozzle Arrangement, and Gas Flow Rate on Mixing Time in Agitated Ladles by Bottom Gas Injection

2013 ◽  
Vol 44 (4) ◽  
pp. 914-923 ◽  
Author(s):  
A. N. Conejo ◽  
S. Kitamura ◽  
N. Maruoka ◽  
S.-J. Kim
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Mixing Time ◽  
Gas Injection ◽  
Gas Flow Rate

scholarly journals Numerical Modeling of Equal and Differentiated Gas Injection in Ladles: Effect on Mixing Time and Slag Eye

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 917
Author(s):  
Luis E. Jardón-Pérez ◽  
Carlos González-Rivera ◽  
Marco A. Ramirez-Argaez ◽  
Abhishek Dutta
Keyword(s):  
Numerical Modeling ◽  
Numerical Model ◽  
Physical Model ◽  
Flow Rate ◽  
Gas Flow ◽  
Mixing Time ◽  
Gas Injection ◽  
Steel Slag ◽  
Gas Flow Rate ◽  
Slag Thickness

Ladle refining plays a crucial role in the steelmaking process, in which a gas stream is bubbled through molten steel to improve the rate of removal of impurities and enhance the transport phenomena that occur in a metallurgical reactor. In this study, the effect of dual gas injection using equal (50%:50%) and differentiated (75%:25%) flows was studied through numerical modeling, using computational fluid dynamics (CFD). The effect of gas flow rate and slag thickness on mixing time and slag eye area were studied numerically and compared with the physical model. The numerical model agrees with the physical model, showing that for optimal performance the ladle must be operated using differentiated flows. Although the numerical model can predict well the hydrodynamic behavior (velocity and turbulent kinetic energy) of the ladle, there is a deviation from the experimental mixing time when using both equal and differentiated gas injection at a high gas flow rate and a high slag thickness. This is probably due to the insufficient capture of the velocity field near the water–oil (steel–slag) interface and slag emulsification by the numerical model, as well as the complicated nature of correctly simulating the interaction between both gas plumes.

scholarly journals Effect of Differentiated Injection Ratio, Gas Flow Rate, and Slag Thickness on Mixing Time and Open Eye Area in Gas-Stirred Ladle Assisted by Physical Modeling

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 555 ◽  
Author(s):  
Luis E. Jardón-Pérez ◽  
Daniel R. González-Morales ◽  
Gerardo Trápaga ◽  
Carlos González-Rivera ◽  
Marco A. Ramírez-Argáez
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Mixing Time ◽  
Flow Ratio ◽  
Gas Flow Rate ◽  
Nsga Ii ◽  
Image Velocimetry ◽  
Gas Flow Ratio ◽  
Slag Thickness ◽  
Injection Ratio

In this work, the effects of equal (50%/50%) or differentiated (75%/25%) gas flow ratio, gas flow rate, and slag thickness on mixing time and open eye area were studied in a physical model of a gas stirred ladle with dual plugs separated by an angle of 180°. The effect of the variables under study was determined using a two-level factorial design. Particle image velocimetry (PIV) was used to establish, through the analysis of the flow patterns and turbulence kinetic energy contours, the effect of the studied variables on the hydrodynamics of the system. Results revealed that differentiated injection ratio significantly changes the flow structure and greatly influences the behavior of the system regarding mixing time and open eye area. The Pareto front of the optimized results on both mixing time and open eye area was obtained through a multi-objective optimization using a genetic algorithm (NSGA-II). The results are conclusive in that the ladle must be operated using differentiated flow ratio for optimal performance.

Mixing of Fluids in Tanks by Gas Bubble Plumes

1987 ◽  
Vol 109 (2) ◽  
pp. 186-193 ◽  
Author(s):  
A. M. Godon ◽  
J. H. Milgram
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Mixing Time ◽  
Empirical Relationship ◽  
Scale Model ◽  
Gas Bubble ◽  
Gas Flow Rate ◽  
Dimensionless Variable ◽  
Bubble Plumes ◽  
The Relationship

The need to rapidly mix treating agent into the oil of a ruptured ship tank motivated scale model experiments of mixing in square-bottomed tanks by gas bubble plumes, The mixing time is primarily governed by the gas flow rate, the plume length and the tank base dimensions; and is quite insensitive to tank height. An empirical relationship between the degree of mixing and a single dimensionless variable is developed and an explanation of the relationship in terms of the fundamentals of the flow is provided.

Effect of Gas Injection with Multi-hole Orifices on Bubble Behavior during Metal Refining

2011 ◽  
Vol 233-235 ◽  
pp. 1940-1945
Author(s):  
Fang Jiang ◽  
Guo Guang Cheng ◽  
Hai Kuo Yang
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Radial Direction ◽  
Gas Injection ◽  
Hole Diameter ◽  
Bubble Coalescence ◽  
Gas Flow Rate ◽  
Bubble Behavior ◽  
Cold Model ◽  
Optimal Distance

Cold model experiments have been conducted to make clear the effect of orifices on bubble behavior based on the comparison of 1-hole and 4-hole configurations. It is found that this effect is closely related to the gas flow rate and the orifice configuration. For 1-hole orifices, bubble behavior is influenced by the hole diameter at low gas flow rate. Nevertheless, in the region of high gas flow rate, this effect becomes less obvious. However, bubble behavior is strongly affected even at high gas flow rate when 4-hole orifices are used. It is also shown there exists an optimal distance between holes for 4-hole orifices. Below this value, the hole distance is too small to adequately avoid bubble coalescence in the radial direction. Above this value, little further contribution to avoidance of bubble coalescence can be made, but weight and cost of the orifices will increase.

scholarly journals An Experimental and Simulated Study on Gas-Liquid Flow and Mixing Behavior in an ISASMELT Furnace

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 565 ◽  
Author(s):  
Hongliang Zhao ◽  
Tingting Lu ◽  
Pan Yin ◽  
Liangzhao Mu ◽  
Fengqin Liu
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Turbulent Viscosity ◽  
Mixing Time ◽  
Water Model ◽  
Mixing Efficiency ◽  
Gas Flow Rate ◽  
Factors Affecting ◽  
Sufficient Energy ◽  
Gas Liquid Flow

In this study, a water-model experiment and numerical simulation were carried out in a pilot ISASMELT furnace to study the factors affecting mixing time. The experimental results were compared to the simulation results to test the accuracy of the latter. To study the internal factors that affect the mixing time, the turbulent viscosity and flow field were calculated using simulation. In addition, following previous research, external factors that influence the mixing time including the depth of the submerged lance, lance diameter, gas flow rate, and the presence of a swirler were studied to investigate their effect on the flow regime. The results indicated that the mixing time is controlled by the turbulent viscosity and velocity vector. In addition, it was found that the lance diameter should not exceed 3.55 cm to maintain sufficient energy for stirring the bath. Finally, the optimal gas flow rate that offers the best mixing efficiency was found to be 50 Nm3/h.

Experimental Study on Mixing in Gas-Stirred Ladles with and without the Slag Phase through a Water Physical Model

2012 ◽  
Vol 1373 ◽  
Author(s):  
Adrián M. Amaro-Villeda ◽  
Jorge A. González Bello ◽  
Marco A. Ramírez-Argáez.
Keyword(s):  
Physical Model ◽  
Flow Rate ◽  
Gas Flow ◽  
Mixing Time ◽  
Steel Slag ◽  
Slag Layer ◽  
Process Conditions ◽  
Steel Ladle ◽  
Gas Flow Rate ◽  
Water Gas

ABSTRACTA 1/6th gas–stirred water physical model of a 140 ton steel ladle is used to evaluate mixing in air–water and air–water–oil systems to model argon–steel and argon–steel–slag systems respectively. Thickness of the slag layer is kept constant at 0.004 m. The effect of the gas flow rate (7, 17, and 37 l/min), plug position (0, 1/3, ½, and 2/3 of the ladle radius, R), and number of plugs (1, 2, and 3) on mixing time is also analyzed in this work. Gas is injected at the bottom of the ladle under several plug configurations varying both position and number of plugs. Chemical uniformity of 95% is selected as mixing criterion. Mixing times are experimentally determined when a tracer is suddenly injected into the ladle and the model is instrumented with a pH meter to track the time evolution of the tracer concentration (NaOH 1 M solution) in a given location inside the ladle. Process conditions for best mixing in both water–gas and water-gas–slag systems are: a single plug located at 2/3 of the ladle radius with a gas flow rate of 17 l/min.

Factors Influencing Foam Height in Gas Injection Process for Aluminum Foams

2015 ◽  
Vol 1104 ◽  
pp. 33-37
Author(s):  
Jian Yu Yuan ◽  
Yan Xiang Li ◽  
Xiang Chen ◽  
Yu Tong Zhou
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Foam Stability ◽  
Gas Injection ◽  
Foam Height ◽  
Gas Flow Rate ◽  
Aluminum Foams ◽  
Particle Content ◽  
Injection Process ◽  
Factors Influencing

The present study proposed a convenient method to characterize the stability of aluminum foams by utilizing the resulting foam height. The factors influencing foam height in gas injection process was investigated including the blowing gas (N2 and air), particle content (5vol.%-15vol.%), gas flow rate (0.03m3/h-0.3m3/h) and orifice size (0.3mm and 0.5mm). Factors that contribute to the foam stability including oxygen in the blowing gas and larger particle content in the melt was proved to be positively related to the foam height. Moreover, it was found that larger gas flow rate and smaller orifice size lead to larger foam height. The cell wall microstructure and thickness was also analyzed to better understand the foaming behavior. The present study offers favorable proof that the foam height in the gas injection process can be a good index for the foam stability.

The theory of injection of a hydrate-forming gas into a snow massif saturated with the same gas

2018 ◽  
Vol 13 (4) ◽  
pp. 92-98 ◽  
Author(s):  
A.S. Chiglintseva ◽  
V.Sh. Shagapov
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Gas Injection ◽  
Hydrate Formation ◽  
Temperature Fields ◽  
Gas Flow Rate ◽  
Initial State ◽  
Gas Hydrate Formation ◽  
Temperature And Pressure ◽  
The Mathematical Model

The mathematical model of the process of gas hydrate formation during gas injection into a snow massif, saturated with the same gas, is constructed. In axisymmetric formulation, analytical solutions are obtained for the distribution of temperature fields, pressures and phase saturations. It is shown that the appearance of various characteristic zones in a snow massif depends on the initial state of the gas–snow system, determined by temperature and pressure, and the mass flow rate of the injected gas. It has been established that an increase in the intensity of gas injection (gas flow rate) leads to an increase in both the length of the bulk zone of hydrate formation and the increase in the fraction of hydrate at the boundary separating the near and intermediate zones.

Effect of Hole Distance and Hole Number on Bubble Behavior during Gas Injection with Multi-Hole Orifices

2011 ◽  
Vol 295-297 ◽  
pp. 1113-1119 ◽  
Author(s):  
Fang Jiang ◽  
Guo Guang Cheng
Keyword(s):  
Physical Model ◽  
Flow Rate ◽  
Gas Flow ◽  
Gas Injection ◽  
Critical Value ◽  
Refining Process ◽  
Hole Diameter ◽  
Gas Flow Rate ◽  
Bubble Behavior ◽  
Hole Number

Physical model experiments have been performed to clarify the effect of hole distance and hole number of multi-hole orifices on bubble behavior during metal refining process. It is found kA/V firstly decreases and then increases with the hole distance increasing. However, kA/V shows little further increase when hole distance exceeds a critical value. There exists an optimal hole distance for the multi-hole orifice, which is dependent on the gas flow rate, the hole diameter and the hole number in the multi-hole orifice. kA/V firstly increases with the hole number increasing, and then remains unchanged when hole number exceeds a critical value. There also exists an optimal hole number for the multi-hole orifice, which is closely related to the gas flow rate.

scholarly journals Geometry Modified Square Edge Orifice Valve Study for Efficiency Gas Lift with Computational Fluid Dynamic (CFD) Method

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Adam Fatchur Rohman ◽  
Sugiatmo Kasmungin ◽  
Dwi Atty Mardiana
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Gas Injection ◽  
Gas Flow Rate ◽  
Design Modification ◽  
Geometry Design ◽  
Production Wells ◽  
Gas Lift ◽  
Orifice Valve

<em>The gas lift lifting system is widely used as an artificial lift on the X Field, with an average depth of gas lift production wells of 3,000-3,500 ft. Design of 3 to 5 Gas lift Valves (GLV) designwith size of 1 inch is ussualy applied. While at the point of gas injection, the GLV square edge orifice is applied. The problem in the optimization of gas lift wells is the flow instability due to gas flow rate fluctuations, the limited volumetric gas injection and limited gas compressor pressure. With the limited compressor pressure, the lift flow and gas design speed is very dependent on the amount of pressure on the compressor, the production wells with limited injection pressure will result in a limited amount of gas injection, the square edge orifice requires a pressure difference of 40% to achieve the maximum gas flow rate. This study aims to find the modification of the GLV orifice geometry to improve the efficiency of the gas lift system so that it can get optimal production. This GLV design modification includes changing the GLV orifice geometry. Design studies using Computational Fluid Dynamic (CFD) simulations aim to analyze any changes in GLV geometry design to the performance of the gas flow rate in the orifice valve described in the valve performance curve. The design modification approach is in accordance with the GLV venturi orifice geometry and the availability of equipment for GLV modification. The CFD simulation results of the first modification geometry by increasing the orifice diameter from 0.25 to 0.5 inch with the condition of upstream 650 psig and downstream 625 psig pressure increasing the injection gas flow rate capacity by 355% and modifying the second geometry with the venturi orifice form by 280%. In modifying the shape of the orifice venture to reach critical flow requires a pressure difference of 10%. Based on simulation results, the modified orifice application is able to increae production up to 44%.</em>

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