Composition of Guests in Hydrates from Gas Mixture
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In industrial and commercial facilities, gas composition must be carefully maintained during storage and transportation to guarantee the gas quality. In this study, we investigated composition of gas in hydrate phase formed from city gas and gas phase. As a result, it was found that the thermodynamic stability is greatly influenced by the heavier components, such as ethane, propane and iso-butane that are contained in a natural gas and a city gas. Also it was found that the equilibrium line of hydrates with methane as the main component was shifted to the low-pressure and high temperature side. Especially, in the formation of mixed gas hydrates, it was shown that inclusion rate of methane, the main ingredient, is comparatively low.Keywords:
Clathrate hydrate
Propane
Gas composition
Butane
Methane gas
Was offered a complex of measures to rise up the safety of work technological equipment by receiving propane-butane on entrails of natural gas in condition of compressornal station.
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Butane
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Abstract Utilising a visual PVT cell, experimental values have been established for the critical temperatures and critical pressures of five mixtures containing ethane, propane and n‐butane, and of two mixtures containing propane and n‐butane. The results are extended by use of experimental critical values reported in the literature for the ethane‐propane, ethane‐n‐butane, and propane‐n‐butane binary systems; a unique graphical technique is applied to generate triangular composition diagrams containing parameters of critical temperature and pressure. These diagrams accurately establish the critical point of ethane‐propane‐n‐butane mixtures over the entire composition range.
Propane
Butane
Alkane
Critical point (mathematics)
Ternary numeral system
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Propane
Butane
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Propane
Butane
Liquefied petroleum gas
Carbon fibers
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ABSTRACT We studied the production of ethylene (C2") and propylene (C3") by the decomposition of pure ethane, propane, and n-butane, mixed with steam, in a microwave-irradiated fixed bed reactor packed with silicon carbide. We found that ethylene production was maximized using ethane as the feed, with per pass yields as high as 63% at an ethane conversion level of 74%. With propane and n-butane feeds, more ethylene than propylene was produced, but the propylene amounts were significant. Combined per pass yields of C2" and C3" were 56% at a butane conversion of 99%, and 50% at a propane conversion of 93%. This microwave process appears to be a viable way of producing ethylene and propylene.
Propane
Butane
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Experiments are reported that show propane is incorporated into clathrate hydrate cages much more rapidly using propane−xenon mixtures than for pure propane gas. Uptake rates for pure propane type II clathrate hydrate, pure xenon type I clathrate hydrate, and propane and xenon binary type II clathrate were studied for several different synthesis procedures. Upon adding a 0.92 xenon:propane ratio gas mixture to ice particles, the time required for achieving 62% of the theoretical yield of propane enclathration is 20 min, versus 3 days for pure propane. Although the acceleration of clathrate formation decreases as xenon is depleted, enhancement continues even after the composition falls below 3% Xe. It appears that xenon serves to nucleate the dodecahedral 512 cages while propane nucleates the larger 51264 cages. The type II xenon−propane structure is not only more thermodynamically stable than either pure hydrate; it is also formed much more quickly than propane clathrate, nearly as fast as type I xenon clathrate.
Clathrate hydrate
Propane
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Experimental NMR measurements for 13C chemical shifts of propane molecules encaged in 16-hedral cages of structure II clathrate hydrate were conducted to investigate the effects of guest−host interaction of pure propane clathrate on the 13C chemical shifts of propane guests. Experimental 13C NMR measurements revealed that the clathrate hydration of propane reverses the 13C chemical shifts of methyl and methylene carbons in propane guests to gaseous propane at room temperature and atmospheric pressure or isolated propane, suggesting a change in magnetic environment around the propane guest by the clathrate hydration. Inversion of the 13C chemical shifts of propane clathrate suggests that the deshielding effect of the water cage on the methyl carbons of the propane molecule encaged in the 16-hedral cage is greater than that on its methylene carbon.
Propane
Clathrate hydrate
Chemical shift
Methylene
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(1) [Mo{(C 6 H 5 ) 2 PC 3 H 6 (C 6 H 5 ) 2 }(CO) 4 ], C 31 H 26 MoO 4 P 2 , cristallise dans Pmma avec a=16,854, b=21,970, c=7,723 A, Z=4; affinement jusqu'a R=0,033. (2) [Mo{(C 6 H 5 ) 2 PC 4 H 8 P(C 6 H 5 ) 2 }(CO) 4 ], C 32 H 28 MoO 4 P 2 , cristallise dans P2 1 /m avec a=12,072, b=15,379, c=16,607 A, β=104,65°, Z=4; affinement jusqu'a R=0,032. Ces deux composes se distinguent par le nombre de chainons du cycle forme par le coordinat et le metal. L'augmentation de l'angle P-Mo-P et la diminution de l'angle cis C-Mo-C entre les composes (1) et (2) proviennent d'un effet du cycle
Butane
Propane
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Vapor pressures of n-butane-ethane, isobutane-ethane, and n-butane-isobutane-propane-ethane systems.
LPG中には最大数%のエタンが含まれており, これが蒸気圧に与える影響は比較的大きい。そこで, 本研究では前報に引きつづいて, n-ブタン-エタン, イソブタン-エタン, n-ブタン-イソブタン-プロパン-エタン4成分系の蒸気圧を, 前報同様273.15～323.15Kの範囲で, 沸点法により測定した。その結果, 実際の蒸気圧は加成的に求めた蒸気圧より低くなることがわかった。さらにこれらの測定結果から, n-ブタン-エタン, イソブタン-エタン系のエタンのヘンリー定数を求めた。また, 前報も含めて, LPGの蒸気圧は各物質ごとにきめたΩa, Ωbを用いた修正 Redlich Kwong 状態式により十分実用的な精度で推算できることがわかった。
Isobutane
Propane
Butane
Alkane
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Hydrogenolysis of propane and n-butane has been studied on highly dispersed Rh on SiO2, Al2O3 and TiO2 catalysts prepared by conventional impregnation, using thermal cycling between ca. 410 and 520 K. Rh/SiO2 is initially the most active for n-butane, but during thermal cycling it deactivates the fastest, with decrease in ethane selectivity S2. Apparent activation energies are ca. 200 kJ mol–1 for propane and ca. 190 kJ mol–1 for n-butane. After the first high-temperature reduction (HTR1), values of S2 in the n-butane reaction are between 1.1 and 1.6; they decrease significantly following oxidation and low-temperature reduction (O/LTR), but rise again after a second high-temperature reduction (HTR2).Dependence of rates of both reactions on H2 pressure at ca. 430 K have been determined for each catalyst after HTR1, and also for Rh/TiO2 after O/LTR. Orders in H2 are strongly negative; the results are modelled by a rate expression derived from a mechanism that assumes activation of the alkane by loss of several H atoms, and values of constants k1(rate constant), KH(H2 chemisorption) and KC(alkane activation), are determined. KH generally exceeds KC, which on Rh/TiO2 is increased by O/LTR treatment. On Rh/SiO2, S2 for the n-butane reaction is independent of H2 pressure, but for the other systems it decreases as the H2 pressure is raised. It is proposed that the chance of central C—C bond splitting in n-butane depends inter alia on the cleanliness of the Rh surface. Ethane selectivity in the propane reaction shows small dependence on either temperature or H2 pressure for all systems, and is typically 0.98–0.99. The lack of a marked dependence of product selectivities on temperature and, except where noted, on H2 pressure is attributed to the strong chemisorption of H2 on these catalysts.
Butane
Hydrogenolysis
Propane
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