Gas separation membrane

A method of fabricating a gas separation membrane includes providing a coextruded multilayer film that includes a first polymer layer formed of a first polymer material and a second polymer layer formed of a second polymer material, the first polymer material having a first gas permeability. The coextruded multilayer film is axially oriented such that the second polymer layer has a second gas permeability that is greater than the first gas permeability.Board of Regents, University of Texas Syste

Karakterrisasi membran selulosa Asetat untuk pemisahan gas.

Proses peraisahan gas banyak dijumpai dalam proses pembuatan zat kimia seperti: pemurnian gas CO2 dari unsur-ungur pembentuknya, penyediaan N2 dan 02 dari udara. sering dipakai sistem destilasi. Dikarenakan biaya pada proses destilasi mahal, mica dicoba digunakan membran sebagai alternatif 1Cinerja membran yang dignnakan untuk pemisahan gas tergantung dad jenis membran, komposisi dan proses pembuatannya Penelitian ini bertujuan untuk mengetahui pengaruh komposisi dan perlakuan pada proses pembuatan membran selulosa asetat terhadap koefisien permeabilitas dan koefisien selektifitas pada pemisahan campuran gas CO2, N2 dan 02. Penelitian dilakukan dengan mengukur besarnya finks gas CO2, 02 dan N2 pada tekanan 0,1; 0,5; 1; 1,5; 2; 2,5 dan 3 atm. Dari harga fluks dapat ditentukan koefisien permeabilitas yang digunakan untuk menentukan koefisien selektifitas yang menunjukkan kemarnpuan pemisahan campuran gas. Dari penehtian jai didapatkan seleklifitas ideal campuran CO2 dengan 02 dengan kemanipuan pemisahan terendah yaitu 1,0198 pada membran dengan komposisi selulosa asetat aseton : air yaitu 11% : 79% : 10%, pada tekanan 1,5 atm, sedangkan tertinggi yaitu 0,000 pada komposisi 10% : 80% : 10%, pada tekanan 1 attn. Selektivitas ideal campuran CO2 dengan N2 dengan kemampuart pemisahan terendah yaitu 0,955 pada membran dengan komposisi selulosa asetat : aseton : air yaitu 11% : 76% : 13%, pada tekanan 3 atm, sedangksn tertinggi yaitu 0,000 pada komposisi 10% : 80% : 10%, pada tekanan 1 atm. Selektivitas ideal campuran 02 dengan N2 dengan ketnampuan pemisahan terendah yaitu 1,00 pada membran dengan komposisi selulosa asetat aseton : air yaitu 9% : 89% : 100/o, pada tekanan 0,5 atm, sedangkan tertinggi yaitu 0,00 pada komposisi 11% : 78%: 11%, pada tekanan 1 atm. Hasil dari penelitian yang telah dilakukan menunjukkan bahwa membran selulosa asetat dapat dipergunakan untuk pemisahan gas. Kernampuan dan finigsi dari membran tergantung clan- komposisi bahan selulosa asetat, aseton dan air serta perlakuan dalam pembuatan membran selulosa asetat tersebut. Pemisahan campuran dua gas dapat diketahui Bari perbandingan koefisien permeabilitas maxi ng-masing gas. Pengaturan tekanan dapat mengoptimalkan basil pemisahan_ Separation process of gas is found in a lot of synthesis of chemical substance, like in purification of CO2 from reactans, separation N2 and 02 from air usually is carried out by distillation system, but its an expensive process. Therefore as an alternative process it is used membranes. Membrane performance tbat is used for gas separation depends on membrane type, composition and the process of membranes production. The objective of this research is to find out the influence of cellulose acetate membrane composition to its performance in separation behaviour of mixture of CO2 with 02, CO2 with N2 and 02 with N2 Each of CO2, 02 and N2 flux was measured at 0,1; 0,5; 1; 1,5; 2; 2,5 and 3 atm respectively. The permeability coefficient was calculated from the flux, which then could be used to determine selectivity coefficient which show the ability of membranes to separate gas mixture. It was found that the ideal selectivity was 1.0198 for mixture of CO2 with 02 for membrane with composition of cellulose acetate : acetone : water 11% : 79% : 100/0 at 1.5 atm. It was the lowest separation ability. While the highest separation ability was 0.000 for membrane with composition of cellulose acetate : acetone : water 10% : 80% : 10% at 1 atm. The ideal selectivity is 0.955 for mixture of CO2 with N2 for membrane with composition of cellulose acetate : acetone : water 11% 76% : 13% at 3 atm. It was the lowest separation ability. While the highest separation ability was 0.000 for membrane with composition of cellulose acetate : acetone : water 10% 80%: 10% at 1 atm. The ideal selectivity was 1.00 for mixture of 02 with N2 for membrane with composition of cellulose acetate : acetone : water 9% : 89% : 10% at 0.5 atm. It was the lowest separation ability. While the highest separation ability was 0.000 was gave by membrane with composition of cellulose acetate : acetone : water 10% : 80% : 10% at 1 atm.. The result of this research show that cellulose acetate membrane could use for gas separation. Capability and function of membrane depend on membrane composition, cellulose acetate, acetone and water, beside these, treatment in membrane synthesing could affect the membrane performance Separation the mixture of two gases could see from comparation of permeability coefficient both of them. Pressure regulation can optimizing the separation resul

Gas separation through carbon nanotubes

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.Layering phenomena of carbon dioxide and methane transported through carbon nanotubes are being examined through molecular dynamics. The layering formation is investigated for carbon nanotubes ranging from (6,6) to (20,20) subjected to pressures spanning between 5-20 bar at 300 K. Well defined layers are developed both in the internal and external surface of the nanotubes for all the examined cases. It is also shown that the number of layers along with their absolute strength varies as a function of the nanotube's diameter, carbon dioxide and methane's density and gas-structure interactions. Finally, the diffusion inside the interior of the nanotubes has been examined showing a Fickian diffusion mode

Separation of gas mixtures by centrifugation

Magnetohydrodynamic (MHD) centrifuge utilizing electric currents and magnetic fields produces a magnetic force which develops supersonic rotational velocities in gas mixtures. Device is superior to ordinary centrifuges because rotation of gas mixture is produced by MHD force rather than mechanical means

Ownership Unbundling of Gas Transmission Networks - Empirical Evidence

The European Commission has intensively discussed the mandatory separation of natural gas transmission from production and services. However, economic theory is ambiguous on the price effects of vertical separation. In this paper, we empirically analyse the effect of ownership unbundling of gas transmission networks as the strongest form of vertical separation on the level of end-user prices. Therefore, we apply different dynamic estimators as system GMM and the bias-corrected least-squares dummy variable or LSDVC estimator on an unbalanced panel out of 18 EU countries over 19 years, allowing us to avoid the endogeneity problem and to estimate the long-run effects of regulation. We introduce a set of regulatory indicators as market entry regulation, ownership structure, vertical separation and market structure and account for structural and economic country specifics. Among these different estimators, we consistently find that ownership unbundling has no impact on natural gas end-user prices, while the more modest legal unbundling reduces them significantly. Furthermore, third-party access, market structure and privatisation show significant influence with the latter leading to higher price levels.Natural gas; Networks; Regulation; Ownership unbundling; Panel data

Criticality in strongly correlated fluids

In this brief review I will discuss criticality in strongly correlated fluids. Unlike simple fluids, molecules of which interact through short ranged isotropic potential, particles of strongly correlated fluids usually interact through long ranged forces of Coulomb or dipolar form. While for simple fluids mechanism of phase separation into liquid and gas was elucidated by van der Waals more than a century ago, the universality class of strongly correlated fluids, or in some cases even existence of liquid-gas phase separation remains uncertain.Comment: Proceedings of Scaling Concepts and Complex Systems, Merida, Mexic

Phase separation and pair condensation in a spin-imbalanced 2D Fermi gas

We study a two-component quasi-two-dimensional Fermi gas with imbalanced spin populations. We probe the gas at different interaction strengths and polarizations by measuring the density of each spin component in the trap and the pair momentum distribution after time of flight. For a wide range of experimental parameters, we observe in-trap phase separation characterized by the appearance of a spin-balanced condensate surrounded by a polarized gas. Our momentum space measurements indicate pair condensation in the imbalanced gas even for large polarizations where phase separation vanishes, pointing to the presence of a polarized pair condensate. Our observation of zero momentum pair condensates in 2D spin-imbalanced gases opens the way to explorations of more exotic superfluid phases that occupy a large part of the phase diagram in lower dimensions

Modeling the gas-particle partitioning of secondary organic aerosol: the importance of liquid-liquid phase separation

The partitioning of semivolatile organic compounds between the gas phase and aerosol particles is an important source of secondary organic aerosol (SOA). Gas-particle partitioning of organic and inorganic species is influenced by the physical state and water content of aerosols, and therefore ambient relative humidity (RH), as well as temperature and organic loading levels. We introduce a novel combination of the thermodynamic models AIOMFAC (for liquid mixture non-ideality) and EVAPORATION (for pure compound vapor pressures) with oxidation product information from the Master Chemical Mechanism (MCM) for the computation of gas-particle partitioning of organic compounds and water. The presence and impact of a liquid-liquid phase separation in the condensed phase is calculated as a function of variations in relative humidity, organic loading levels, and associated changes in aerosol composition. We show that a complex system of water, ammonium sulfate, and SOA from the ozonolysis of α-pinene exhibits liquid-liquid phase separation over a wide range of relative humidities (simulated from 30% to 99% RH). Since fully coupled phase separation and gas-particle partitioning calculations are computationally expensive, several simplified model approaches are tested with regard to computational costs and accuracy of predictions compared to the benchmark calculation. It is shown that forcing a liquid one-phase aerosol with or without consideration of non-ideal mixing bears the potential for vastly incorrect partitioning predictions. Assuming an ideal mixture leads to substantial overestimation of the particulate organic mass, by more than 100% at RH values of 80% and by more than 200% at RH values of 95%. Moreover, the simplified one-phase cases stress two key points for accurate gas-particle partitioning calculations: (1) non-ideality in the condensed phase needs to be considered and (2) liquid-liquid phase separation is a consequence of considerable deviations from ideal mixing in solutions containing inorganic ions and organics that cannot be ignored. Computationally much more efficient calculations relying on the assumption of a complete organic/electrolyte phase separation below a certain RH successfully reproduce gas-particle partitioning in systems in which the average oxygen-to-carbon (O:C) ratio is lower than ~0.6, as in the case of α-pinene SOA, and bear the potential for implementation in atmospheric chemical transport models and chemistry-climate models. A full equilibrium calculation is the method of choice for accurate offline (box model) computations, where high computational costs are acceptable. Such a calculation enables the most detailed predictions of phase compositions and provides necessary information on whether assuming a complete organic/electrolyte phase separation is a good approximation for a given aerosol system. Based on the group-contribution concept of AIOMFAC and O:C ratios as a proxy for polarity and hygroscopicity of organic mixtures, the results from the α-pinene system are also discussed from a more general point of view

Bose-Einstein condensation in multilayers

The critical BEC temperature $T_{c}$ of a non interacting boson gas in a layered structure like those of cuprate superconductors is shown to have a minimum $T_{c,m}$, at a characteristic separation between planes $a_{m}$. It is shown that for $a<a_{m}$, $T_{c}$ increases monotonically back up to the ideal Bose gas $T_{0}$ suggesting that a reduction in the separation between planes, as happens when one increases the pressure in a cuprate, leads to an increase in the critical temperature. For finite plane separation and penetrability the specific heat as a function of temperature shows two novel crests connected by a ridge in addition to the well-known BEC peak at $T_{c}$ associated with the 3D behavior of the gas. For completely impenetrable planes the model reduces to many disconnected infinite slabs for which just one hump survives becoming a peak only when the slab widths are infinite.Comment: Four pages, four figure