Separation Features in Hydrocarbon Media at Thermobaric Regimes of Petroleum Preparation Devices Functioning

2017 ◽  
Vol 743 ◽  
pp. 373-377
Author(s):  
Eugenii V. Nikolayev ◽  
Sergey N. Kharlamov ◽  
Laura Meucci
Keyword(s):  
Physical Properties ◽  
Gas Phase ◽  
Transport Processes ◽  
Gas Mixture ◽  
Multicomponent Systems ◽  
Composition Change ◽  
Separation Processes ◽  
Exchange Processes ◽  
Temperature And Pressure ◽  
Hydrocarbon Media

In this paper the features of separation processes modelling are analyzed in hydrocarbonic media within the limits of thermodynamics of equilibrium states. Approaches to calculation of phase equilibrium in multicomponent systems are discussed. Regularities and peculiarities of composition change of gas mixture depending on the temperature and pressure are studied. It has been established that there are specific conditions of non-monotonic change of composition with extremums for some separation regimes that significantly influences the physical properties and intensity of exchange processes at the heat-and mass transfer in multicomponent hydrocarbon media. In addition, the details of the behavior of gas phase with changing its thermal and physical properties have been discussed. Also, the calculated distributions of Prandtl, Schmidt and Lewis-Semenov numbers essentially influencing on the intensity of transport processes are considered.

scholarly journals An Atmospheric Origin for HCN-Derived Polymers on Titan

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 965
Author(s):  
Zoé Perrin ◽  
Nathalie Carrasco ◽  
Audrey Chatain ◽  
Lora Jovanovic ◽  
Ludovic Vettier ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Gas Phase ◽  
Formation Process ◽  
Upper Atmosphere ◽  
Gas Mixture ◽  
Space Probe ◽  
Atmospheric Haze ◽  
Formation And Evolution ◽  
Haze Formation

Titan’s haze is strongly suspected to be an HCN-derived polymer, but despite the first in situ measurements by the ESA-Huygens space probe, its chemical composition and formation process remain largely unknown. To investigate this question, we simulated the atmospheric haze formation process, experimentally. We synthesized analogues of Titan’s haze, named Titan tholins, in an irradiated N2–CH4 gas mixture, mimicking Titan’s upper atmosphere chemistry. HCN was monitored in situ in the gas phase simultaneously with the formation and evolution of the haze particles. We show that HCN is produced as long as the particles are absent, and is then progressively consumed when the particles appear and grow. This work highlights HCN as an effective precursor of Titan’s haze and confirms the HCN-derived polymer nature of the haze.

DECOMPOSITION PRESSURES OF FERRIC SULPHATE AND ALUMINUM SULPHATE

1960 ◽  
Vol 38 (11) ◽  
pp. 2196-2202 ◽  
Author(s):  
N. A. Warner ◽  
T. R. Ingraham
Keyword(s):  
Gas Phase ◽  
Static System ◽  
Ferric Sulphate ◽  
Kcal Mole ◽  
Aluminum Sulphate ◽  
Temperature And Pressure ◽  
Pressure Changes ◽  
Mercury Manometer ◽  
Decomposition Pressure ◽  
Gas Pressures

The gas pressures over samples of anhydrous ferric sulphate and anhydrous aluminum sulphate have been measured in a static system, using a mercury manometer in which the exposed surface was covered with a flexible Pyrex bellows. The calculated ΔH for the decomposition of Fe2(SO4)3 was +135.4 kcal/mole. It was not possible to calculate the ΔH for the Al2(SO4)3 decomposition, because a discrete aluminum oxide with singular thermodynamic properties was not obtained.In the Fe2(SO4)3 system, the fraction of SO3 in the gas phase was found to be almost constant over the range of temperature and pressure changes used in the study.At any given temperature, the decomposition pressure over a ferric sulphate sample is greater than that over an aluminum sulphate sample, thus indicating that preferential decomposition of ferric sulphate should be thermodynamically feasible in mixtures of ferric sulphate and aluminum sulphate.

Fabrication and Physical Properties of Coatings Belonging to W, Ta, Hf, Ti, Mo, Cr, Al and C Based Multicomponent Systems

2020 ◽  
Vol 42 (6) ◽  
pp. 388-395
Author(s):  
Yu. O. Kosminska ◽  
G. S. Kornyushchenko ◽  
Yu. V. Gannych ◽  
V. I. Perekrestov
Keyword(s):  
Physical Properties ◽  
Multicomponent Systems ◽  
Properties Of Coatings

scholarly journals Pressure dependent low temperature kinetics for CN + CH3CN: competition between chemical reaction and van der Waals complex formation

2016 ◽  
Vol 18 (22) ◽  
pp. 15118-15132 ◽  
Author(s):  
Chantal Sleiman ◽  
Sergio González ◽  
Stephen J. Klippenstein ◽  
Dahbia Talbi ◽  
Gisèle El Dib ◽  
...  
Keyword(s):  
Low Temperature ◽  
Complex Formation ◽  
Gas Phase ◽  
Rate Coefficient ◽  
Flow Reactor ◽  
Slow Flow ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Low Temperature Kinetics ◽  
Temperature And Pressure

The gas phase reaction between the CN radical and acetonitrile CH3CN was investigated experimentally with a CRESU apparatus and a slow flow reactor as well as theoretically to explore the temperature and pressure dependence of its rate coefficient from 354 K down to 23 K.

Transport and reaction of aromatics, O2 and CO2 within a membrane bound biofilm in competition with suspended biomass

1995 ◽  
Vol 31 (1) ◽  
pp. 129-141 ◽  
Author(s):  
Oliver Debus
Keyword(s):  
Gas Phase ◽  
Transport Processes ◽  
Pure Oxygen ◽  
Bulk Liquid ◽  
Bulk Fluid ◽  
Biofilm Thickness ◽  
Suspended Biomass ◽  
Membrane Bound ◽  
Laboratory Reactor ◽  
Experimental Values

The biological removal of volatile o-, m-, p-xylene and ethylbenzene from the bulk fluid was investigated in a stirred laboratory reactor. The biofilm was grown on a gas-permeable silicone membrane tubing through which oxygen was supplied. A mathematical simulation could adequately reproduce the experimental values for the biofilm thickness and the concentrations for several species for both sides of the biofilm: in the bulk liquid and in the gas phase. A high xylene conversion plateau of more than 90% was determined by the chronologically occurrence of two sub-maxima: conversion by suspended biomass and by the biofilm. The two maxima can be explained by the spatial transport processes of oxygen and xylene in the biofilm. The first sub-maximum of the conversion by suspended biomass is determined by a maximum oxygen flux through the membrane-bound biofilm. Later oxygen becomes limiting in the bulk and less xylene is degraded by suspended biomass and a maximum transport of xylene into the biofilm occurred, which led to a maximum conversion of xylene within the biofilm. For biodegradable organic compounds, the biofilm can totally reduce the transfer of these compounds into the gas phase. If compounds are non-degradable a biofilm with a thickness of 2 mm reduces the transfer into the gas phase only by 35%. Therefore, the application of pure oxygen and low volumetric gas rates are necessary to reduce the transfer of compounds that are not biodegradable. The transfer of CO2 into the gas phase of the membrane-bound biofilm is very important for the stabilization of the pH in the biofilm and the bulk. The transfer of CO2 from the biofilm into the gas phase is up to 6 times higher than the transfer of CO2 from the biofilm into the bulk. The pH-minimum in the biofilm is not more than 0.15 pH-units below the pH in the bulk.

scholarly journals Квантово-химическое моделирование эндофуллеренов металлов подгруппы скандия

2020 ◽  
Vol 22 (3) ◽  
pp. 360-372
Author(s):  
Дмитрий Александрович Мачнев ◽  
Игорь Владимирович Нечаев ◽  
Александр Викторович Введенский ◽  
Олег Александрович Козадеров
Keyword(s):  
Gas Phase ◽  
Quantum Chemical ◽  
Chem Phys ◽  
Program System ◽  
Separation Processes ◽  
Molecular Systems ◽  
De Vries ◽  
Free Molecules ◽  
New Form ◽  
Buckminsterfullerene C60

Эндофуллерены, содержащие один или несколько атомов металла внутри углеродного каркаса (металлофуллерены), представляют большой практический интерес в связи с возможностью создания на их основе эффективных контрастирующих агентов для магнитно-резонансной томографии (МРТ), антиоксидантных и противораковых средств. Данные соединения могут быть также использованы в спинтронике для создания наноразмерных электронных устройств. В настоящей работе в рамках теории функционала плотности произведен расчет структурных, электронных и термодинамических характеристик эндофуллеренов металлов подгруппы скандия с числом инкапсулированных атомов от одного до семи в газовой фазе. Описаны стабильные структуры с симметриямиCs, C2, C3 и Ci, соответствующие позициям, занимаемым атомами металла внутри каркаса фуллерена. Установлен теоретический предел числа атомов металла, при котором структура эндофуллерена сохраняет устойчивость – шесть атомов для скандия, четыре для иттрия и три для лантана. Расчет показывает, что наиболее устойчивыми являются структуры с двумя и тремя инкапсулированными атомами. Описана зависимость между числом инкапсулированных атомов металла и характером распределения электронной плотности. Общий заряд на инкапсулированном металлическом кластере положителен для соединений Me@C60 – Me3@C60, слабо положителен для Me4@C60(отдельные атомы имеют отрицательный заряд) и отрицателен для соединений Me5C60 – Me6@C60. Описан эффект спиновой утечки для структур с основным дублетным спиновым состоянием. Для соединений с тремя и более инкапсулированными атомами данный эффект незначителен, что указывает на нецелесообразность создания контрастирующих агентов для МРТ на их основе.         ЛИТЕРАТУРА 1. Kroto H. W., Heath J. R., O’Brien S. C., Curl R. F., Smalley R. E. C60: Buckminsterfullerene. Nature.1985;318(6042): 162–163. DOI: https://doi.org/10.1038/318162a02. Kratschmer W., Lamb L. D., Fostiropoulos K., Huffman D. R. Solid C60: a new form of carbon. Nature.1990;347(6291): 354–358. DOI: https://doi.org/10.1038/347354a03. Buchachenko A. L. Compressed atoms. J. Phys. Chem. B. 2001;105(25): 5839–5846. DOI: https://doi.org/10.1021/jp003852u4. Koltover V. K., Bubnov V. P., Estrin Y. I., Lodygina V. P., Davydov R. M., Subramoni M., Manoharan P. T.Spin-transfer complexesofendohedralmetallofullerenes: ENDOR and NMR evidences. Phys. Chem. Chem. Phys. 2003;5(13): 2774–2777. DOI:https://doi.org/10.1039/b302917d5. Raebiger J. W., Bolskar R. D. Improved production and separation processes for gadoliniummetallofullerenes. J. Phys. Chem. C. 2008;112(17): 6605–6612. DOI:  https://doi.org/10.1021/jp076437b6. Gaussian 09, Revision D.01. M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb,J. R. Cheeseman, G. Scalmani, V. Barone, G. A. Petersson, H. Nakatsuji, X. Li, M. Caricato, A. Marenich, J. Bloino,B. G. Janesko, R. Gomperts, B. Mennucci, H. P. Hratchian, J. V. Ortiz, A. F. Izmaylov, J. L. Sonnenberg, D. Williams-Young, F. Ding, F. Lipparini, F. Egidi, J. Goings, B. Peng, A. Petrone, T. Henderson, D. Ranasinghe, V. G. Zakrzewski,J. Gao, N. Rega, G. Zheng, W. Liang, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida,T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven,K. Throssell, J. A. Montgomery, Jr., J. E. Peralta,F. Ogliaro, M. Bearpark, J. J. Heyd, E. Brothers, K. N. Kudin, V. N. Staroverov, T. Keith, R. Kobayashi,J. Normand, K. Raghavachari, A. Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, J. M. Millam, M. Klene,C. Adamo, R. Cammi, J. W. Ochterski, R. L. Martin, K. Morokuma, O. Farkas, J. B. Foresman, and D. J. Fox,Gaussian, Inc., Wallingford CT, 2016. Available at: http://gaussian.com/g09citation7. Neese F. The ORCA program system. WIREs Computational Molecular Science. 2012;2(1): 73–78.DOI: https://doi.org/10.1002/wcms.818. Laikov D. N., Ustynyuk Y. A. PRIRODA-04: a quantum-chemical program suite. New possibilitiesin the study of molecular systems with the application of parallel computing. Russian Chemical Bulletin.2005;54(3): 820–826. DOI: https://doi.org/10.1007/s11172-005-0329-x9. Chandrasekharaiah M. S., Gingerich K. A. Chapter 86 Thermodynamic properties of gaseousspecies. In: Handbook on the Physics and Chemistry of Rare Earths. 1989;12: 409–431. DOI: https://doi.org/10.1016/s0168-1273(89)12010-810. Kohl F. J., Stearns C. A. Vaporization thermodynamics of yttrium dicarbide–carbon systemand dissociation energy of yttrium dicarbide and tetracarbide. J. Chem. Phys., 1970;52(12): 6310–6315.DOI: https://doi.org/10.1063/1.167294211. Gingerich K. A., Nappi B. N., Pelino M., Haque R. Stability of complex dilanthanum carbide molecules.Inorganica Chimica Acta. 1981;54: L141–L142. DOI: https://doi.org/10.1016/s0020-1693(00)95414-812. Hedberg K., Hedberg L., Bethune D. S., Brown C. A., Dorn H. C., Johnson R. D., de Vries M. S.Bond lengths in free molecules of buckminsterfullerene, C60, from gas-phase electron diffraction.Science. 1991;254(5030): 410–412. DOI: https://doi.org/10.1126/science.254.5030.41013. Bethune D. S., Meijer G., Tang W. C., Rosen H. J., Golden W. G., Seki H., Brown C. F., de Vries M. S.Vibrational Raman and infrared spectra of chromatographically separated C60 and C70 fullereneclusters Chem. Phys. Lett., 1991; 179(1–2): 181–186.DOI: https://doi.org/10.1016/0009-2614(91)90312-w14. Эмсли Дж. Элементы. М.: Мир; 1993. 256 c.15. Раков Э. Г. Нанотрубки и фуллерены. Учебн. пособие. М.: Логос; 2006. 376 с.16. Елецкий А. В., Смирнов В. М. Фуллерены. Успехи физических наук.1993;2: 33–60. Режим доступа: https://ufn.ru/ru/articles/1993/2/b/

scholarly journals Influence of Vibration on Diffusion in Liquid Mixtures On-Board the International Space Station

2021 ◽  
Author(s):  
Aram Parsa
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Physical Properties ◽  
International Space Station ◽  
Diffusion Coefficients ◽  
Space Station ◽  
Flow Patterns ◽  
Transport Processes ◽  
International Space ◽  
Different Levels

Experiments on-board the International Space Station experience a convective flow due to the oscillatory g-jitters induced by several sources such as crew activities, mechanical systems, thrusters firing, spacecraft docking, etc. Although g-jitter seems to have a major impact on diffusion-related experiments in Space, very few experimental studies have addressed this topic. This study examined the effect of oscillatory g-jitters on transport processes (fluid flow, heat transfer and mass transfer). Cubic rigid cells filled with water and isopropanol at different concentrations were subjected to thermal gradients and forced vibrations. The cells were exposed to different levels of vibration in terms of frequency and amplitude, which were applied perpendicular to the temperature gradient. The full transient Navier Stokes equations coupled with the mass and heat transfer formulas were solved numerically using the control volume technique. The physical properties of the fluid mixture such as the density were determined using two different models. The effect of different levels of vibration on the flow was analysed and the results were compared in a benchmark study with other scientific groups. The effect of the diffusion coefficients variation and other physical properties on the temperature and concentration distribution was compared to those results obtained with constant diffusion coefficients. Results show that use of variable physical properties in the modelling produces different flow patterns and component concentration. By examining different flow patterns, it was found that the effect of using variable coefficients is much more significant in the cases with high Rayleigh vibration that result in strong flow when compared with numerical analysis using constant variables. The numerical analysis was also performed for the actual experiment on board the International Space Station. The same trend was seen for both the numerical and experimental results. However, the separation of components was higher in the experiment in comparison with the numerical analysis. This was discussed in detail for various scenarios in terms of the applied frequency and amplitude. Recommendations are made according to the findings from this study for the improvement of accuracy in the numerical and experimental analyses of future diffusion experiments in Space.

scholarly journals Influence of Vibration on Diffusion in Liquid Mixtures On-Board the International Space Station

2021 ◽  
Author(s):  
Aram Parsa
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Physical Properties ◽  
International Space Station ◽  
Diffusion Coefficients ◽  
Space Station ◽  
Flow Patterns ◽  
Transport Processes ◽  
International Space ◽  
Different Levels

Experiments on-board the International Space Station experience a convective flow due to the oscillatory g-jitters induced by several sources such as crew activities, mechanical systems, thrusters firing, spacecraft docking, etc. Although g-jitter seems to have a major impact on diffusion-related experiments in Space, very few experimental studies have addressed this topic. This study examined the effect of oscillatory g-jitters on transport processes (fluid flow, heat transfer and mass transfer). Cubic rigid cells filled with water and isopropanol at different concentrations were subjected to thermal gradients and forced vibrations. The cells were exposed to different levels of vibration in terms of frequency and amplitude, which were applied perpendicular to the temperature gradient. The full transient Navier Stokes equations coupled with the mass and heat transfer formulas were solved numerically using the control volume technique. The physical properties of the fluid mixture such as the density were determined using two different models. The effect of different levels of vibration on the flow was analysed and the results were compared in a benchmark study with other scientific groups. The effect of the diffusion coefficients variation and other physical properties on the temperature and concentration distribution was compared to those results obtained with constant diffusion coefficients. Results show that use of variable physical properties in the modelling produces different flow patterns and component concentration. By examining different flow patterns, it was found that the effect of using variable coefficients is much more significant in the cases with high Rayleigh vibration that result in strong flow when compared with numerical analysis using constant variables. The numerical analysis was also performed for the actual experiment on board the International Space Station. The same trend was seen for both the numerical and experimental results. However, the separation of components was higher in the experiment in comparison with the numerical analysis. This was discussed in detail for various scenarios in terms of the applied frequency and amplitude. Recommendations are made according to the findings from this study for the improvement of accuracy in the numerical and experimental analyses of future diffusion experiments in Space.

scholarly journals Numerical Simulation of a New Porous Medium Burner with Two Sections and Double Decks

Processes ◽  
2018 ◽  
Vol 6 (10) ◽  
pp. 185 ◽  
Author(s):  
Zhenzhen Jia ◽  
Qing Ye ◽  
Haizhen Wang ◽  
He Li ◽  
Shiliang Shi
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Porous Medium ◽  
Industrial Development ◽  
High Efficiency ◽  
Methane Combustion ◽  
Combustion Mechanism ◽  
Gas Mixture ◽  
Temperature And Pressure ◽  
Save Energy

Porous medium burners are characterized by high efficiency and good stability. In this study, a new burner was proposed based on the combustion mechanism of the methane-air mixture in the porous medium and the preheating effect. The new burner is a two-section and double-deck porous medium with gas inlets at both ends. A mathematical model for the gas mixture combustion in the porous medium was established. The combustion performance of the burner was simulated under different equivalence ratios and inlet velocities of premixed gas. The methane combustion degree, as well as the temperature and pressure distribution, was estimated. In addition, the concentrations of emissions of NOx for different equivalence ratios were investigated. The results show that the new burner can not only realize sufficient combustion but also save energy. Furthermore, the emission concentration of NOx is very low. This study provides new insights into the industrial development and application of porous medium combustion devices.

Sign in / Sign up

Export Citation Format

Share Document