The Effects of Gas Mixture Composition on the Mass Transfer and Individual Diffusion Coefficient in CH4-CO2-Light Oil Systems

2021 ◽  
Author(s):  
Taiyi Zheng ◽  
Yongcheng Luo ◽  
Yu Shi ◽  
Xiangui Liu ◽  
Zhengming Yang ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Mass Transfer Rate ◽  
Molar Fraction ◽  
High Mass ◽  
Gas Mixture ◽  
Light Oil ◽  
The Individual ◽  
Tight Formation

Abstract Limited CO2 resources considerably narrow down the field application of CO2 EOR for improving oil recovery in tight formation. Considering that CH4 and CO2 have similar EOR mechanisms, CH4, as a by-product of produced oil, is a relatively cost-efficient agent to be injected into the tight formation with CO2. In this work, experimental and mathematical methods are proposed to probe the effect of CH4 composition on the mass transfer between a CO2-CH4 gas mixture and crude oil collected from a tight oil reservoir. Experimentally, the pressure-decay tests for different CH4-CO2-light oil systems are conducted at a constant temperature in a pressure / volume / temperature (PVT) setup. Also, the gas mixtures’ compositions before and after the experiments are analyzed with gas chromatography to investigate the mass transfer of different components. Theoretically, mathematical formulations are developed to describe the mass transfer between the gas mixture and light oil based on translated Peng Robinson equation of state (PR-EOS), a real gas equation, and one-dimensional convection-diffusion equations. The individual diffusion coefficients of CH4 and CO2 as well as the concentrations distribution can be obtained by minimizing the deviation between the calculated pressure and the measured ones. The results indicate that the higher the content of CO2 in the initial gas phase, the faster the pressure drops are and less time it takes for the oil and gas phases to reach a stable pressure, which implies a high mass transfer rate with an increase in CO2 composition. In particular, the diffusion coefficient of CO2 is found to be about 2 times larger than that of CH4 the same composition condition. However, it is noted that the individual diffusion coefficients of CH4 or CO2 are not constants. A high molar fraction in the initial gas sample will lead to a large diffusion coefficient in different CH4-CO2-light oil systems.

The Influence of Grain Form on Effective Diffusion Coefficient of Polycrystalline

2015 ◽  
Vol 756 ◽  
pp. 529-533
Author(s):  
Marija V. Chepak-Gizbrekht ◽  
Anna G. Knyazeva
Keyword(s):  
Mass Transfer ◽  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Effective Diffusion Coefficient ◽  
Effective Properties ◽  
Mass Transfer Rate ◽  
Effective Diffusion ◽  
High Mass ◽  
Know How ◽  
Nonlinear Character

To study the behavior of materials with special properties, such as micro and nanograin structure, it is necessary to know how the size and the form of grain influences on the effective properties of the material. In particular, for materials with fine-dispersed structure characterized by high mass transfer rate, which could be due to several reasons. To study this kind of materials is necessary to build mathematical models taking into account the peculiarities that arise from the transition to the micro structure of the macrostructure. This paper presents a method of calculating the effective diffusion coefficient, which takes into account the influence of the size and form of grains. This method could be useful for the construction of multilayer models of mass transfer. On the example of hexagonal polycrystalline material shown that the dependence of the effective diffusion coefficient of the angle at the grain boundary acquires nonlinear character with the increase of grain boundary layer.

scholarly journals Optical Low States of the Supersoft X-Ray Source RXJ0513.9–6951

1997 ◽  
Vol 163 ◽  
pp. 787-787
Author(s):  
K. Reinsch ◽  
A. van Teeseling ◽  
K. Beuermann ◽  
T.M.C. Abbott
Keyword(s):  
Mass Transfer ◽  
White Dwarf ◽  
Mass Transfer Rate ◽  
Central Star ◽  
High Mass ◽  
X Ray ◽  
Total Luminosity ◽  
Nuclear Burning ◽  
Sudden Decrease ◽  
Optical Flux

The transient luminous soft X-ray source RXJ0513.9–6951 (Schaeidt et al., 1993, A&A 270, L9) is a high-mass-transfer binary system (Cowley et al., 1993, ApJ 418, L63; Pakull et al., 1993, A&A 278, L39) with a probable orbital period of 0.76 days (Crampton et al., 1996, ApJ 456, 320). Here, we summarize the results of a quasi-simultaneous optical and X-ray monitoring (see Fig. 1). The sudden decrease of the optical flux, the accompanying reddening, and the turn-on in the soft X-ray band can be quantitatively described by variations in the irradiation of the accretion disk by the hot central star (Reinsch et al., 1996, A&A 309, L11). In this simple model, we consider a white dwarf with nuclear burning of accreted matter (van den Heuvel et al., 1992, A&A 262, 97), surrounded by a flat standard disk. In the optical high state, accretion at near-Eddington rate occurs and the white dwarf photospheric radius must be considerably expanded causing an enhanced illumination of the disk and the secondary. In the optical low state, the photosphere shrinks in response to a temporarily slightly reduced mass-transfer rate. At the same time, the effective temperature increases, and the soft X-ray flux becomes detectable with ROSAT. This model does not depend on the particular cause for the drop in the accretion rate and can describe the optical/ X-ray variability with the total luminosity changing by less than 20 %.

A Power-Law Mixing Rule for Predicting Apparent Diffusion Coefficients of Binary Gas Mixtures in Heavy Oil

2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Hyun Woong Jang ◽  
Daoyong Yang ◽  
Huazhou Li
Keyword(s):  
Diffusion Coefficient ◽  
Apparent Diffusion Coefficient ◽  
Heavy Oil ◽  
Diffusion Coefficients ◽  
Gas Mixtures ◽  
Gas Diffusion ◽  
Gas Mixture ◽  
Mixing Rule ◽  
Heavy Oils ◽  
Apparent Diffusion

A power-law mixing rule has been developed to determine apparent diffusion coefficient of a binary gas mixture on the basis of molecular diffusion coefficients for pure gases in heavy oil. Diffusion coefficient of a pure gas under different pressures and different temperatures is predicted on the basis of the Hayduk and Cheng's equation incorporating the principle of corresponding states for one-dimensional gas diffusion in heavy oil such as the diffusion in a pressure–volume–temperature (PVT) cell. Meanwhile, a specific surface area term is added to the generated equation for three-dimensional gas diffusion in heavy oil such as the diffusion in a pendant drop. In this study, the newly developed correlations are used to reproduce the measured diffusion coefficients for pure gases diffusing in three different heavy oils, i.e., two Lloydminster heavy oils and a Cactus Lake heavy oil. Then, such predicted pure gas diffusion coefficients are adjusted based on reduced pressure, reduced temperature, and equilibrium ratio to determine apparent diffusion coefficient for a gas mixture in heavy oil, where the equilibrium ratios for hydrocarbon gases and CO2 are determined by using the equilibrium ratio charts and Standing's equations, respectively. It has been found for various gas mixtures in two different Lloydminster heavy oils that the newly developed empirical mixing rule is able to reproduce the apparent diffusion coefficient for binary gas mixtures in heavy oil with a good accuracy. For the pure gas diffusion in heavy oil, the absolute average relative deviations (AARDs) for diffusion systems with two different Lloydminster heavy oils and a Cactus Lake heavy oil are calculated to be 2.54%, 14.79%, and 6.36%, respectively. Meanwhile, for the binary gas mixture diffusion in heavy oil, the AARDs for diffusion systems with two different Lloydminster heavy oils are found to be 3.56% and 6.86%, respectively.

Vapor Condensation and Absorption of SO2 in Wet Flue Gas

2003 ◽  
Author(s):  
Li Jia ◽  
Xiaofeng Peng
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Flue Gas ◽  
Phase Interface ◽  
Vapor Condensation ◽  
High Mass ◽  
Condensation Process ◽  
Gas Mixture ◽  
Vapor Fraction ◽  
So2 Absorption

The convection-condensation heat transfer mechanism of the gas mixture and its influence on SO2 absorption were theoretically analyzed with vapor fraction of 8% to 28%. A modified film model of mass transfer in mixture gas and Nusselt theory were used to describe the characteristics of mass, momentum and energy transfer at the phase interface. The effects of the velocities induced by mass transfer (vapor condensation and SO2 absorption) were included in conducting governing equations. Vapor condensation improves the SO2 absorption in the wet flue gas. Vapor fraction in the gas mixture would alter the mechanism of heat transfer modes, single-phase convection or condensation. But for high mass fraction of vapor the SO2 absorption will be an important phenomenon in the condensation process. Another important factor influencing the SO2 absorption is the Re number of bulk flow of wet flue gas.

scholarly journals SWSex Stars, Old Novae, and the Evolution of Cataclysmic Variables

2015 ◽  
Vol 2 (1) ◽  
pp. 188-191 ◽  
Author(s):  
L. Schmidtobreick ◽  
C. Tappert
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Cataclysmic Variables ◽  
High Mass ◽  
Period Range ◽  
Transfer Rates ◽  
Low Mass ◽  
Orbital Periods ◽  
Nova Outburst

The population of cataclysmic variables with orbital periods right above the period gap are dominated by systems with extremely high mass transfer rates, the so-called SW Sextantis stars. On the other hand, some old novae in this period range which are expected to show high mass transfer rate instead show photometric and/or spectroscopic resemblance to low mass transfer systems like dwarf novae. We discuss them as candidates for so-called hibernating systems, CVs that changed their mass transfer behaviour due to a previously experienced nova outburst. This paper is designed to provide input for further research and discussion as the results as such are still very preliminary.

scholarly journals Heat and mass transfer in 3-D MHD Williamson-Casson fluids flow over a stretching surface with non-uniform heat source/sink

2019 ◽  
Vol 23 (1) ◽  
pp. 281-293 ◽  
Author(s):  
Chakravarthula Raju ◽  
Naramgari Sandeep ◽  
Mohamed Ali ◽  
Abdullah Nuhait
Keyword(s):  
Mass Transfer ◽  
Heat Source ◽  
Heat And Mass Transfer ◽  
Mass Transfer Rate ◽  
Casson Fluid ◽  
Heterogeneous Reactions ◽  
Stretching Surface ◽  
Flow Heat ◽  
The Individual ◽  
Source Sink

A mathematical model has been proposed for investigating the flow, heat, and mass transfer in Williamson and Casson fluid-flow over a stretching surface. For controlling the temperature and concentration fields we considered the space and temperature dependent heat source/sink and homogeneous-heterogeneous reactions, respectively. Numerical results are carried out for this study by using Runge-Kutta based shooting technique. The effects of governing parameters on the flow, heat and mass transfer are illustrated graphically. Also computed the skin-friction coefficients for axial and transverse directions along with the local Nusselt number. In most of the studies, homogeneous-heterogeneous profiles were reduced into a single concentration equation by assuming equal diffusion coefficients. For the physical relevance, without any assumptions we studied the individual behavior of the homogeneous-heterogeneous profiles. It is found that the rate of heat and mass transfer in Casson fluid is significantly large while equated with the heat and mass transfer rate of Williamson fluid.

scholarly journals MASS TRANSFER CORRELATION FOR THE REMOVAL OF COPPER IONS FROM WASTEWATER

2010 ◽  
Vol 9 (1-2) ◽  
pp. 63
Author(s):  
N. M. S. Kaminari ◽  
M. J. J. S. Ponte ◽  
H. A. Ponte
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Copper Ions ◽  
Mass Transfer Rate ◽  
Reynolds Numbers ◽  
Electrochemical Reactor ◽  
High Mass ◽  
Ore Processing ◽  
Lead Nickel ◽  
Copper Lead

One of the biggest problems with ore processing in extractive metallurgical industries is the high toxicity of the heavy metals waste content (e.g., copper, lead, nickel and chrome). This work investigates the copper (II) íons removal from aqueous solutions in concentrations up to 1000 ppm. Therefore, a fluidized bed electrolytic reactor was used with flow-by configuration considered as a hopeful method due to the large specific surface area and the high mass transfer rate. The performance of the electrochemical reactor was investigated by using different porosities. Dimensionless Sherwood and Reynolds numbers were correlated to characterize the mass transport properties of the reactor, and they were fitted to the equation Sh = a.Reb.Sc1/3.

scholarly journals 1RXS J232953.9+062814: A Possible Progenitor of AM CVn Stars

2004 ◽  
Vol 194 ◽  
pp. 109-110
Author(s):  
M. Uemura
Keyword(s):  
Mass Transfer ◽  
Mass Transfer Rate ◽  
Cataclysmic Variables ◽  
High Mass ◽  
Recurrence Time ◽  
Apparent Magnitude ◽  
Evolutionary Status ◽  
Transfer Rates ◽  
Secondary Star ◽  
Orbital Periods

AbstractWe revealed that the hydrogen-rich cataclysmic variable lRXS J232953.9+062814 is an SU UMa-type dwarf nova with a superbump period of 66.774±0.010 min. A photometric orbital period is determined to be 64.184± 0.003 min, which is below the period minimum. Although the standard evolutionary scenario of cataclysmic variables predicts lower mass-transfer rates in systems with shorter orbital periods, its short recurrence time of outbursts and bright apparent magnitude indicate that this object has a relatively high mass-transfer rate. With the analogous system V485 Cen, these objects establish the first subpopulation in hydrogen-rich cataclysmic variables below the period minimum. Concerning the evolutionary status of them, we propose that they are progenitors of AM CVn stars on evolutionary courses in which systems have an evolved secondary star with a hydrogen-exhausted core.

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