Thermal conductivities of binary gas mixtures at high pressures: nitrogen-oxygen, nitrogen-argon, carbon dioxide-argon, and carbon dioxide-methane

During the researches upon high-pressure explosions of carbonic oxide-air, hydrogen-air, etc., mixtures, which have been described in the previous papers of this series, a mass of data has been accumulated relating to the influence of density and temperature upon the internal energy of gases and the dissociation of steam and carbon dioxide. Some time ago, at Prof. Bone’s request, the author undertook a systematic survey of the data in question, and the present paper summarises some of the principal results thereof, which it is hoped will throw light upon problems interesting alike to chemists, physicists and internal-combustion engineers. The explosion method affords the only means known at present of determining the internal energies of gases at very high temperatures, and it has been used for this purpose for upwards of 50 years. Although by no means without difficulties, arising from uncertainties of some of the assumptions upon which it is based, yet, for want of a better, its results have been generally accepted as being at least provisionally valuable. Amongst the more recent investigations which have attracted attention in this connection should be mentioned those of Pier, Bjerrum, Siegel and Fenning, all of whom worked at low or medium pressures.

Download Full-text

Volumetric behaviour of (carbon dioxide + hydrocarbon) mixtures at high pressures

The Journal of Supercritical Fluids ◽

10.1016/j.supflu.2016.01.002 ◽

2016 ◽

Vol 110 ◽

pp. 103-109 ◽

Cited By ~ 8

Author(s):

Johnny Zambrano ◽

Franklin V. Gómez-Soto ◽

Daniel Lozano-Martín ◽

M. Carmen Martín ◽

José J. Segovia

Keyword(s):

Carbon Dioxide ◽

High Pressures ◽

Hydrocarbon Mixtures

Download Full-text

The structure of the high pressure carbon bands and the swan system

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1929.0145 ◽

1929 ◽

Vol 124 (795) ◽

pp. 668-688 ◽

Cited By ~ 15

Keyword(s):

Carbon Dioxide ◽

Carbon Monoxide ◽

High Pressure ◽

High Pressures ◽

Carbon Electrodes ◽

High Dispersion ◽

Pressure System ◽

True Nature ◽

Discharge Tubes ◽

Condensed Discharge

The so-called high pressure “ CO ” bands—or high pressure carbon bands, as they are better called—were first found by Fowler* in 1910 in tubes containing carbon monoxide at relatively high pressures. The system was described as consisting of some six apparently double-headed bands degraded to the violet, their wave-lengths being approximately at— 6441 6420 } 5897 5878 } 5431 5413 } 5030 5015 } 4679 4663 } 4365 4353 } Å. U. In 1923 the conditions of production of this spectrum were further investigated by Merton and Johnson who obtained the bands with considerable strength by condensed discharges in capillary tubes fitted with carbon electrodes, and containing CO at pressures of 5 mm. and more. It was found that while the high pressure bands and the Swan bands were mingled in the light from the capillary of the tube, the former bands were isolated in bluish jets where the two ends of the capillary merged into the wider parts of the tube. Further observations indicated that the introduction of a little C0 2 destroyed the bands, but that the system re-apppeared after a few minutes, in which time presumably the carbon dioxide had been reduced to monoxide by the carbon electrodes. A reproduction of these bands photographed under low dispersion is given in the above-mentioned paper. No further experimental work appears to have been done on this system, and it has not been correlated with any other band system or assigned any place in the system of electronic levels of the CO molecule. We have therefore made an attempt to photograph the system under high dispersion with a view to fine structure analysis and identification of the molecular emitter. For this purpose large discharge tubes having a bore of about 15 to 20 mm. and a length of 60 or 70 cm. were used. These had at least one of the electrodes made of carbon and were fitted with side bulbs containing caustic potash and phosphorus pentoxide and a palladium regulator. The tubes were filled with carbon monoxide to such a pressure (probably 20-40 mm.) that a condensed discharge could just be forced through by the ¼ kilowatt 15,000 volt transformer used. Some of the tubes had large side flasks attached to them, increasing thereby the volume of gas in the tube, and giving the tubes a life of 4 to 6 hours during which the high pressure bands were emitted strongly. After some such period the pressure fell below the optimum value, and deposits of carbon had accumulated on the walls of the tube. Impurities such as hydrogen, carbon dioxide, and water-vapour were found to inhibit formation of the high pressure bands, and the tube always attained its best condition after running for about an hour (removing meanwhile any little hydrogen present through the regulator). Under these conditions the wide bore is practically filled with light, and presents a remarkable appearance, as of dense pale blue puffs of smoke (showing the high pressure system), threaded by a narrow green ribbon (showing the Swan system). If side tubes having a fair capacity ( e . g ., flasks) are attached to the discharge tube the high pressure glow is capable of diffusion into these. The appearance is suggestive of an afterglow emitter, but if this is its true nature it is of very short duration. Photographs of the H. P. bands were taken in times varying from 4 to 10 hours in the first order of a 21-foot grating. The green band in the neighbourhood of λ 5000 is exceedingly faint and was not attempted. Before considering the results -obtained it will be an advantage to summarise our present knowledge of the Swan spectrum and its emitter, with which it will subsequently be shown that the high pressure carbon system is intimately related.

Download Full-text

Molecular Simulations of CO2/CH4, CO2/N2 and N2/CH4 Binary Mixed Hydrates

Colloid Journal ◽

10.1134/s1061933x21030145 ◽

2021 ◽

Vol 83 (3) ◽

pp. 372-378

Author(s):

A. A. Sizova ◽

S. A. Grintsevich ◽

M. A. Kochurin ◽

V. V. Sizov ◽

E. N. Brodskaya

Keyword(s):

Carbon Dioxide ◽

Monte Carlo ◽

Monte Carlo Simulations ◽

Gas Hydrates ◽

Molecular Simulations ◽

Gas Mixtures ◽

Gas Mixture ◽

Grand Canonical Monte Carlo ◽

Multicomponent Gas ◽

Grand Canonical

Abstract Grand canonical Monte Carlo simulations were performed to study the occupancy of structure I multicomponent gas hydrates by CO2/CH4, CO2/N2, and N2/CH4 binary gas mixtures with various compositions at a temperature of 270 K and pressures up to 70 atm. The presence of nitrogen in the gas mixture allows for an increase of both the hydrate framework selectivity to CO2 and the amount of carbon dioxide encapsulated in hydrate cages, as compared to the CO2/CH4 hydrate. Despite the selectivity to CH4 molecules demonstrated by N2/CH4 hydrate, nitrogen can compete with methane if the gas mixture contains at least 70% of N2.

Download Full-text