The Experts below are selected from a list of 162831 Experts worldwide ranked by ideXlab platform
Mingjun Chen - One of the best experts on this subject based on the ideXlab platform.
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investigation of enhancing multi Gas Transport ability of coalbed methane reservoir by oxidation treatment
Fuel, 2020Co-Authors: Zhangxin Chen, Mingjun Chen, Yili Kang, Lijun You, Jiang LiuAbstract:Abstract Subbituminous coal (Coal S) and anthracite coal (Coal A) were taken as the coal samples and H2O2, NaClO and ClO2 as the oxidants to investigate multi-Gas Transport ability enhancement of coalbed methane reservoir after oxidation. Thin section, dissolution rate and organic carbon content were measured to analyze the mechanism for different coal ranks and various oxidants. The dissolution rate of Coal A was greater than Coal S because large amounts of ferrous ions in Coal A had strong catalytic effect on Fenton reaction. However, there was large amounts of siderite composed of ferric ions in Coal S, which did not catalyze Fenton reaction. Meanwhile, the adsorption/ desorption behavior of both raw and treated coal samples was measured. Results show that, besides reaction between oxidants and organic matter/ pyrite/ clay minerals could destroy methane adsorption point in coals, weakening methane adsorption capacity. Also, the Gas Transport channels were widened and interconnected due to the oxidation dissolution and significant temperature increment during oxidation reaction. It is indicated that the reaction between coals and oxidants accelerated methane desorption, widened the methane mass transfer channel, and finally enhanced the methane multi-Gas Transport ability of methane in coal. The order of multi-Gas Transport ability enhancement by oxidation treatment under the condition of similar redox potential of oxidants was Coal ASFW > Coal AClO2 > Coal ANaClO > Coal AH2O2 and that of Coal S was Coal SSFW > Coal SH2O2 > Coal SNaClO > Coal SClO2.
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Investigation of multi-scale Gas Transport behavior in organic-rich shale
Journal of Natural Gas Science and Engineering, 2016Co-Authors: Mingjun Chen, Bin Yang, Yili Kang, Weihong Wang, Hua LiuAbstract:Abstract Gas flow in shale is controlled by different space scales and time scales due to its ultra-fine pore structure, high content of clay minerals, high content of organic matter and serious anisotropy. In this work, multi-scale Gas Transport in organic-rich shale is investigated by theoretical modeling and pore structure analysis. Characteristics of multi-scale Gas Transport in shale are sufficiently confirmed through study of multi-scale flow tube, multi-scale pore structure and multi-scale flow regime. The effect of Knudsen diffusion on non-linear Gas flow in shale is analyzed. Contribution of Knudsen diffusion to apparent Gas permeability is calculated to be greater at the lower pressure or permeability. Knudsen diffusion coefficient and its corresponding hydraulic radius are calculated to be lower at the lower permeability or higher pressure. Finally, an equivalent permeability formula is put forward to model the apparent permeability of shale at specific pressure, temperature and petrophysics. The increase multiples of permeability for Gas slippage during the development of the studied shale Gas reservoir is determined, indicating that the effect of non-linear flow on shale permeability measurement and well production forecast should be paid abundant attention. Results from this study are beneficial to comprehensively understand multi-scale Gas Transport in shale.
E A Sedova - One of the best experts on this subject based on the ideXlab platform.
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Gas Transport properties of new aromatic cardo poly aryl ether ketone s
Journal of Membrane Science, 2006Co-Authors: Claudia Camachozuniga, F A Ruiztrevino, Mikhail G Zolotukhin, L F Del Castillo, J Guzman, Juan B Chavez, G Torres, N G Gileva, E A SedovaAbstract:Abstract New cardo poly(aryl ether ketone)s containing side phthalide groups and aryl ether ketones in different lengths have been synthesized and characterized in terms of their thermal, volumetric and Gas Transport properties to H 2 , O 2 , N 2 , CH 4 and CO 2 . The polymers show high glass transition temperature (218–420 °C), good solubility in chlorinated solvents and strong acids as well as excellent thermal stability (decomposition temperatures above 510 °C). The most permeable membrane studied shows permeability coefficients of 11 to O 2 and 72 to CO 2 , with ideal selectivity factors of 4.6 for the pair O 2 /N 2 and 25 for CO 2 /CH 4 . The results, interpreted in terms of chain rigidity and chain packing ability, show that decreasing the length of the connector moieties between the cardo groups increases the fractional free volume, the glass transition temperature and the Gas permeability coefficients.
Falin Chen - One of the best experts on this subject based on the ideXlab platform.
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reactant Gas Transport and cell performance of proton exchange membrane fuel cells with tapered flow field design
Journal of Power Sources, 2006Co-Authors: Chyi Yeou Soong, Falin ChenAbstract:The objective of this work is to examine the reactant Gas Transport and the cell performance of a proton exchange membrane fuel cell (PEMFC) with a tapered flow channel design. It is expected that, with the reduction in the channel depth along the streamwise direction, the reactant fuel Gas in the tapered channel can be accelerated as well as forced into the Gas diffuser layer to enhance the electrochemical reaction and thus augment the cell performance. The effects of liquid water formation on the reactant Gas Transport are taken into account in the present study. Numerical predictions show that the cell performance can be enhanced with the fuel channel tapered, and the enhancement is more noticeable at a lower voltage. The results also reveal that the liquid water effect in general influences the cell performance and the effect becomes significant at lower voltages.
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analysis of reactant Gas Transport in a pem fuel cell with partially blocked fuel flow channels
Journal of Power Sources, 2005Co-Authors: Chyi Yeou Soong, C Y Tseng, Falin ChenAbstract:Abstract In the present study, we propose a novel configuration of partially blocked fuel channel with baffle plates transversely inserted in the channel. The effects of the blockage with various gap ratios and numbers of the baffle plates, the fuel flow Reynolds number and the porosity of the diffusion layer on the reactant Gas Transport, and the pressure drop across the channel length are explored. A two-dimensional model of one-side porous-walled channel with the presence of baffle plates is considered. An approximate analysis is performed first to examine the qualitative natures of the flow in the gap region and then numerical simulations for the parametric study of the reactant Gas Transport in a half-cell model are carried out. The velocity field, the oxygen mass flux/flow rate reaching the catalyst layer, the concentration of the water vapor produced, the fraction of the fuel Gas entering the diffusion layer, and the pressure drop at various conditions are analyzed. The results reveal that reducing the gap size and/or increasing the baffle number to enhance the reactant Gas Transport results in a penalty of high pressure-loss. Among the parameters considered in the present work, the gap ratio has the most remarkable impact on the variation of the pressure drop. Very high pressure-loss can be generated due to high flow resistance at a low gap ratio combined with a low Gas diffusion layer (GDL) porosity. With the consideration of both high performance and reasonable pressure drop, the present results disclose that designs with the baffle gap ratio no smaller than 0.1, number of baffle plates N = 3–5, and the GDL porosity around 0.7 seem quite appropriate.
Zhangxin Chen - One of the best experts on this subject based on the ideXlab platform.
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investigation of enhancing multi Gas Transport ability of coalbed methane reservoir by oxidation treatment
Fuel, 2020Co-Authors: Zhangxin Chen, Mingjun Chen, Yili Kang, Lijun You, Jiang LiuAbstract:Abstract Subbituminous coal (Coal S) and anthracite coal (Coal A) were taken as the coal samples and H2O2, NaClO and ClO2 as the oxidants to investigate multi-Gas Transport ability enhancement of coalbed methane reservoir after oxidation. Thin section, dissolution rate and organic carbon content were measured to analyze the mechanism for different coal ranks and various oxidants. The dissolution rate of Coal A was greater than Coal S because large amounts of ferrous ions in Coal A had strong catalytic effect on Fenton reaction. However, there was large amounts of siderite composed of ferric ions in Coal S, which did not catalyze Fenton reaction. Meanwhile, the adsorption/ desorption behavior of both raw and treated coal samples was measured. Results show that, besides reaction between oxidants and organic matter/ pyrite/ clay minerals could destroy methane adsorption point in coals, weakening methane adsorption capacity. Also, the Gas Transport channels were widened and interconnected due to the oxidation dissolution and significant temperature increment during oxidation reaction. It is indicated that the reaction between coals and oxidants accelerated methane desorption, widened the methane mass transfer channel, and finally enhanced the methane multi-Gas Transport ability of methane in coal. The order of multi-Gas Transport ability enhancement by oxidation treatment under the condition of similar redox potential of oxidants was Coal ASFW > Coal AClO2 > Coal ANaClO > Coal AH2O2 and that of Coal S was Coal SSFW > Coal SH2O2 > Coal SNaClO > Coal SClO2.
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real Gas Transport in shale matrix with fractal structures
Fuel, 2018Co-Authors: Zhangxin ChenAbstract:Abstract A real Gas Transport model in shale matrix with fractal structures is established to bridge a pore size distribution and multiple Transport mechanisms. This model is well validated with experiments. Results indicate that different pore size distributions lead to various Transport efficiencies of shale matrix. A larger fractal dimension of the pore size and a smaller minimum pore size yield higher frequency of occurrence of small pores and a lower free Gas Transport ratio, which further results in lower Transport efficiency. Gas Transport efficiency due to pore size distribution parameters (a fractal dimension and a minimum pore size) varies with different porosities and pressures. Increasing fractal dimension and decreasing minimum pore size result in a higher contribution of Knudsen diffusion to the total Gas Transport. Decreased pressure and increased porosity enhance the sensitivity of Gas Transport efficiency to a pore size distribution. The relationship between apparent permeability and porosity based on different pore size distributions is also established for industrial application.
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real Gas Transport through nanopores of varying cross section type and shape in shale Gas reservoirs
Chemical Engineering Journal, 2015Co-Authors: Zhangxin ChenAbstract:Abstract A model for real Gas Transport in nanopores of shale Gas reservoirs (SGRs) was proposed on the basis of the weighted superposition of slip flow and Knudsen diffusion, where the ratios of the intermolecular collisions and the molecule–nanopore wall collisions to the total collisions are the weighted factors of slip flow and Knudsen diffusion, respectively. The present model takes account of slip effect and real Gas effect, additionally, the effects of cross-section type and its shape of nanopores on Gas Transport are also considered in this paper. The present model is successfully validated against existing molecular simulation data collected from different sources in literature. The results show: (1) the present model is reasonable to describe all of the Gas Transport mechanisms known, including continuum flow, slip flow and transition flow in nanopores of SGRs; (2) the cross-section type and shape of nanopores both affect Gas Transport capacity: at the same cross-sectional area, Gas Transport capacity of nanopores with a circular cross section is greater than that with a rectangular cross section, and Gas Transport capacity of nanopores with a rectangular cross section decreases with an increasing aspect ratio; compared to the cross-section type, the effect of the cross-section shape on Gas Transport capacity is stronger; (3) a real Gas effect improves Gas Transport capacity, which becomes more obvious with an increasing pressure and a decreasing pore size; (4) and compared to nanopores with a circular cross section, the effect of real Gas effect on Gas Transport capacity of nanopores with a rectangular cross section is stronger, and the effect increases with an increasing aspect ratio. The proposed model can provide some theoretical support in numerical simulation of reservoir behavior in SGRs.
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a model for Gas Transport in microfractures of shale and tight Gas reservoirs
Aiche Journal, 2015Co-Authors: Keliu Wu, Chenchen Wang, Xiangfang Li, Zhangxin Chen, Wei YuAbstract:A model for Gas Transport in microfractures of shale and tight Gas reservoirs is established. Slip flow and Knudsen diffusion are coupled together to describe general Gas Transport mechanisms, which include continuous flow, slip flow, transitional flow, and Knudsen diffusion. The ratios of the intermolecular collision frequency and the molecule-wall collision frequency to the total collision frequency are defined as the weight coefficients of slip flow and Knudsen diffusion, respectively. The model is validated by molecular simulation results. The results show that: (1) the model can reasonably describe the process of the mass transform of different Gas Transport mechanisms; (2) fracture geometry significantly impacts Gas Transport. Under the same fracture aperture, the higher the aspect ratio is, the stronger the Gas Transport capacity, and this phenomenon is more pronounced in the cases with higher Gas pressure and larger fracture aperture. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2079–2088, 2015
Tianlu Chen - One of the best experts on this subject based on the ideXlab platform.
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Gas Transport properties of novel cardo poly aryl ether ketone s with pendant alkyl groups
Macromolecules, 2000Co-Authors: Zhonggang Wang, Tianlu ChenAbstract:Gas Transport of hydrogen, oxygen, nitrogen, carbon dioxide, and methane in four cardo poly(aryl ether ketone)s containing different alkyl substituents on the phenyl ring has been examined from 30 to 100 degrees C. The permeability, diffusivity, solubility, and their temperature dependency were studied by correlations with Gas shape, size, and critical temperature as well as polymeric structural factors including glass transition, secondary transition, cohesive energy density, and free volume. The bulky, stiff cardo and alkyl groups in tetramethyl-substituted TMPEK-C resulted in increased H-2 permeability (by 55%) and H-2/N-2 permselectivity (by 106%) relative to bisphenol A polysulfone (PSF). Moreover, the weak dependence of Gas Transport on temperature in TMPEK-C made it maintain high permselectivities (alpha(H2/N2) in 68.3 and alpha(O2/N2) in 5.71) up to 100 degrees C, exhibiting potential for high-temperature Gas separation applications.
