Propane adsorption

Preferential sorption in the sinusoidal channels was confirmed by Nicholas et al. (67) in an MD study of methane and propane adsorption. This preference was most noticeable at infinite dilution at a loading of 12 molecules per unit cell the distribution of molecules over the channels was found to be close to that expected from the relative volumes of the channel segments. The propane molecules were predicted to spend more time in the intersections than the straight channel at infinite dilution. This result is rationalized by considering the slow motion of the molecules and the conformational changes necessary to move from one channel type to another via an intersection. The distribution of propane backbone bond angles was predicted to be similar to that of gas-phase propane, indicating the rather minor effect of the zeolite on the internal coordinates of propane. 

V + and V + /Mo + center provides a particnlarly nncleophilic bridging oxygen critical for propane activation. The Mo + sites have been shown to act as propane adsorption and nitrogen insertion sites in bismnth molybdates, which are also used for propane anunoxidation. 

As judged by propane adsorption at —78°, almost all of the micropore structure is accessible to propane but, since equilibrium with... 

Figure 3.2-5 Plot of ln(K) versus 1/n for propane adsorption on activated carbon...

Characterisation of Nanoporous Aluminosilicate Monoliths Derivatised with Metal Cations for Selective Propene-Propane Adsorption... 

McMaster MC, Ammainayagam CR, Madix RJ Molecular propane adsorption dynamics on Pt(lll), Chem Phys 177(2) 461M72, 1993. 

Fig. 4J Langmuir plots (a) for propane on 5A zeolite (courtesy Ruthven) (fc) for carbon monoxide on zeolite CaY-54 (courtesy Stone). In (a) the adsorption is expressed in terms of number C of molecules of adsorbate per cavity in (b), as m (stp).

Fig. 3. Adsorption of hydrocarbons by 2eobtes is much greater for unsaturated hydrocarbons whose molecules contain double or triple bonds. From top to bottom, the curves show adsorption (at 150°C) of propjiene, ethylene, acetjiene, and isobutjiene (unsaturated) and propane, ethane, and methane...

Many simple systems that could be expected to form ideal Hquid mixtures are reasonably predicted by extending pure-species adsorption equiUbrium data to a multicomponent equation. The potential theory has been extended to binary mixtures of several hydrocarbons on activated carbon by assuming an ideal mixture (99) and to hydrocarbons on activated carbon and carbon molecular sieves, and to O2 and N2 on 5A and lOX zeoHtes (100). Mixture isotherms predicted by lAST agree with experimental data for methane + ethane and for ethylene + CO2 on activated carbon, and for CO + O2 and for propane + propylene on siUca gel (36). A statistical thermodynamic model has been successfully appHed to equiUbrium isotherms of several nonpolar species on 5A zeoHte, to predict multicomponent sorption equiUbria from the Henry constants for the pure components (26). A set of equations that incorporate surface heterogeneity into the lAST model provides a means for predicting multicomponent equiUbria, but the agreement is only good up to 50% surface saturation (9). 

Natural gas Hquids are recovered from natural gas using condensation processes, absorption (qv) processes employing hydrocarbon Hquids similar to gasoline or kerosene as the absorber oil, or soHd-bed adsorption (qv) processes using adsorbants such as siHca, molecular sieves, or activated charcoal. Eor condensation processes, cooling can be provided by refrigeration units which frequently use vapor-compression cycles with propane as the refrigerant or by... 

Less propane and butanes are produced compared to natural gas Hquids by the adsorption process than are obtained normally for the same gas by the oil-absorption process. Because adsorption efficiency increases with a decrease in temperature, the adsorption cycle should operate at the lowest temperature that is economically feasible. 

Solid-Bed Dehydration. Sihca gel, bauxite, activated alurnina, or molecular sieves can be used for removing dissolved water to meet propane specifications. The soHd-bed dehydrators are used in a cycHc adsorption process. After an adsorption cycle has completed, the bed is heated with a purge gas or a vaporized Hquid-product stream for regeneration. If the latter is used, the Hquid product is condensed, separated from the free water, and returned to the process. After the beds are regenerated, they are cooled and returned to the adsorption cycle. 

Propane-propylene Close-hoihng Acrylonitrile Alternative to simple distillation, adsorption... 

In the first step, in which the molecules of the fluid come in contact with the adsorbent, an equihbrium is established between the adsorbed fluid and the fluid remaining in the fluid phase. Figures 25-7 through 25-9 show several experimental equihbrium adsorption isotherms for a number of components adsorbed on various adsorbents. Consider Fig. 25-7, in which the concentration of adsorbed gas on the solid is plotted against the equilibrium partial pressure p of the vapor or gas at constant temperature. At 40° C, for example, pure propane vapor at a pressure of 550 mm Hg is in equilibrium with an adsorbate concentration at point P of 0.04 lb adsorbed propane per pound of silica gel. Increasing the pressure of the propane will cause... 

Additional adsorption sites are provided on open metal sites, when available. [Cu3(BTC)2] is performant in the selective adsorption and separation of olefinic compounds. The highly relevant separations of propene from propane and of isobutene from isobutane have been accomplished with separation factors of 2.0 and 2.1, respectively [101, 102]. [Cu3(BTC)2] also selectively takes up pentene isomers from aliphatic solvent in liquid phase, and even discriminates between a series of cis- and trans-olefin isomer mixtures with varying chain length, always preferring a double bond in cis-position. This behavior is ascribed to tt -complexation with the open Cu sites [100]. 

We have shown that the steam reforming of propane may be adequately described by LH mechanism involving different adsorption sites for steam and hydrocarbon. The associated model satisfied both statistical compliance and the BMV thermodynamic criterion. 

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