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.

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.

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.

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.

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>

scholarly journals Effect of Gas Flow Rate on Hydrate Formation Within the Hydrate Stability Zone

2018 ◽  
Vol 123 (8) ◽  
pp. 6263-6276 ◽  
Author(s):  
Dylan W. Meyer ◽  
Peter B. Flemings ◽  
David DiCarlo
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Hydrate Formation ◽  
Stability Zone ◽  
Gas Flow Rate ◽  
Hydrate Stability

scholarly journals Mathematical modeling of the process of decomposition of gas hydrate formation without the influence of various external sources

2019 ◽  
Vol 14 (1) ◽  
pp. 63-66
Author(s):  
V.E. Yuziev ◽  
A.A. Rusinov
Keyword(s):  
Hydrate Formation ◽  
Temperature Fields ◽  
Reservoir Pressure ◽  
Initial State ◽  
Gas Recovery ◽  
Gas Hydrate Formation ◽  
Dimensional Approximation ◽  
Hydrate Saturation ◽  
Basic Equations ◽  
Hydration Layers

The paper considers a homogeneous reservoir in the form of a pancake with characteristic linear dimensions corresponding to real deposits: with a radius of the order of several kilometers, and a height of tens of meters. Since the radii of such layers are much larger than their thickness, this allows one to take into account the thermal interactions of the field with the surrounding rocks through the upper and lower boundaries of the layer in a flat one-dimensional approximation. To describe the model, such basic equations were used as the law of conservation of mass of gas and water in the reservoir, the equation of heat balance and temperature fields near the reservoir boundary, as well as initial and boundary conditions. The constructed theoretical model makes it possible to analyze the possibility of realizing the complete gas recovery of the layers only due to the thermal reserve of the hydration layers themselves, as well as the surrounding mountain massif. For the values of the parameters that determine the initial state of the board, numerical experiments were performed. The dynamics of reservoir pressure and hydrate saturation in the reservoir are presented. As a result of the research, it was established that at a constant gas extraction rate, the achievement of reservoir pressure up to 2.6 MPa and, accordingly, a temperature of 273 K occurred in about 5 years. It is shown that when gas is taken from a reservoir with a radius of 3000 m and a thickness of 50 m, its hydrate saturation decreases by about 38% over 5 years.

scholarly journals Evaluation of the Critical Gas Flow Rate Using Water Model for the Entrapment of Slag into a Metal Bath Subject to Gas Injection

1993 ◽  
Vol 79 (5) ◽  
pp. 569-575 ◽  
Author(s):  
Manabu IGUCHI ◽  
Yutaka SUMIDA ◽  
Ryusuke OKADA ◽  
Zen-ichiro MORITA
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Gas Injection ◽  
Water Model ◽  
Gas Flow Rate ◽  
Metal Bath

High Power Glow Discharge Using Gas Injection Multiple Porous Electrodes

1987 ◽  
Vol 98 ◽  
Author(s):  
J. E. Harry ◽  
D. R. Evans
Keyword(s):  
Glow Discharge ◽  
Flow Rate ◽  
Gas Flow ◽  
Gas Injection ◽  
Porous Electrodes ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Glow Discharges ◽  
Power Loading ◽  
Power Inputs

ABSTRACTGlow discharges have been operated at power inputs of 25 kW at 50 mb and discharge currents up to 2 A at gas flow rates of up to 0.04 kg/s in a 100 mm diameter cavity 0.5 m long. This has been made possible by the use of multiple anodes and cathodes combined with gas injection at the porous anodes. Power loading in excess of 700 kW/kg/s have been achieved. The power density of the gas (W/m3) and the current at which the glow to arc transition occurs scaled with both the number of electrode pairs and the gas flow rate through the porous anodes over the range of investigation.

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