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

1929 ◽  
Vol 124 (795) ◽  
pp. 668-688 ◽  
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.

scholarly journals Gaseous combustion at high pressures. —Part X. The co-volume corrections, maximum temperatures and dissociation of steam and carbon dioxide in explosions

1928 ◽  
Vol 119 (782) ◽  
pp. 464-480
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Internal Energy ◽  
High Temperatures ◽  
High Pressures ◽  
Internal Combustion ◽  
Systematic Survey ◽  
Explosion Method ◽  
Maximum Temperatures ◽  
Very High

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.

The Reaction of Carbon with Carbon Dioxide at High Pressure

1960 ◽  
Vol 13 (2) ◽  
pp. 194 ◽  
Author(s):  
JD Blackwood ◽  
AJ Ingeme
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Active Sites ◽  
High Pressures ◽  
Carbon Dioxide Molecule ◽  
Partial Pressures ◽  
Different Temperatures ◽  
Adsorbed Carbon ◽  
Forward Process ◽  
High Carbon Dioxide

A study has been made of the reactions of purified carbon with carbon dioxide at pressures up to 40 atm and in the temperature range 790-870 �C. The effect of carbon monoxide has been examined by adding varying proportions of this gas to the carbon dioxide supplied to the reactor bed. At high carbon dioxide and carbon monoxide partial pressures, the rate of formation of carbon monoxide is greater than would be expected from the mechanism proposed by Gadsby et al. (1948). A mechanism has been proposed whereby the increased rate may be explained by additional steps involving the interaction of a carbon dioxide molecule with an adsorbed carbon monoxide to produce adsorbed oxygen, thus : ������������������ CO2 + (CO) → 2CO +(O) A general rate equation has been derived which includes this step and satisfies the experimental results. The reverse mechanism by which carbon monoxide can disappear is not the simple reverse of the forward process and at high pressures equilibrium cannot be expressed by the usual expression derived for the simple single-stage reversible process. The possible nature of active sites has been examined by studying the reactivity of a series of chars prepared at different temperatures. The reactivity appears to be related to the oxygen content of the chars and the type of active centres involved may be different from those which control the carbon-steam mechanism.

High Pressure Solubility of Carbon Dioxide and Carbon Monoxide in Dimethyl Ether

1995 ◽  
Vol 40 (1) ◽  
pp. 296-300 ◽  
Author(s):  
Ari Jonasson ◽  
Ole Persson ◽  
Aage Fredenslund
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
High Pressure ◽  
Dimethyl Ether

scholarly journals Synthesis and Characterization of Nanosize Catalyst for the RWGS Process and Performance Examination using a Pilot-Scale High-Pressure Reactor

2019 ◽  
Vol 9 (1) ◽  
pp. 5215-5220
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
High Pressure ◽  
Raw Materials ◽  
Chemical Characterization ◽  
Calorific Value ◽  
Pilot Scale ◽  
Ammonium Molybdate ◽  
X Ray

Catalyst reduces the activation energy of molecules and is generally composed of an active part distributed on a large surfaced stable support or ligand. Since the catalytic reactions occur at the surface of the catalyst, this necessitates the method of catalysts preparation after suitable pretreatment to have an active, moderately high and accessible surface area. Also, the pretreated catalysts should have sufficient mechanical strength and stability so that the particles will remain relatively unchanged during their use as catalysts. Nanosize metal oxide catalysts deposited on alpha-alumina are prepared using combustion synthesis in the present work. Alumina acts as support, a promoter as well as a catalyst in this process. Aluminum nitrate, cobaltous chloride, nickel chloride, ammonium molybdate, and urea are used as raw materials to synthesize cobalt-nickel-molybdenum on alumina by combustion method. The solution at 500oC in a muffle furnace produced voluminous solid within 5 minutes. Particle size, morphology, chemical characterization of the sample were analyzed by scanning electron microscopy (500 nm), X-ray diffraction, and energy disperses X-ray analysis techniques. The results showed that the concentration of nickel among all three promoters was the least. Increasing levels of carbon dioxide in the atmosphere have detrimental effects such as an increase in temperatures, melting of glaciers, the rise in the levels of seas and oceans, submergence of low-lying land areas and disruptions in the ecological cycles. In order to combat this, the present work was extended to convert carbon dioxide to carbon monoxide by reverse water gas shift reaction. Carbon monoxide can be later used to produce methanol and dimethyl ether which has a higher calorific value. Present process was carried out in a pilot-scale high-pressure reactor at 400 ℃ and 7 bar using nanoparticles of nickel-cobalt-molybdenum on alumina. Product stream was analyzed by gas chromatography with a thermal conductivity detector.

Tribological Studies of Compressor Surfaces in the Presence of Carbon Dioxide Under Extreme Environmental Pressure Conditions

2005 ◽  
Author(s):  
Nicholaos G. Demas ◽  
Andreas A. Polycarpou
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
High Pressures ◽  
Environmental Pressures ◽  
Thermodynamic Studies ◽  
Environmental Pressure ◽  
Ultra High Pressure ◽  
Carbon Dioxide Co2 ◽  
Internal Pressures ◽  
Very High

The refrigeration industry has shown an inclination towards the use of carbon dioxide (CO2) as a refrigerant in some applications. While extensive thermodynamic studies exist, tribological studies with CO2 are limited and tribological testing has further been restricted to low environmental pressures up to 1.38 MPa (200 psi) due to limitations in equipment capabilities. In this work, experiments were performed using an Ultra High Pressure Tribometer (UHPT) that was custom designed and built for tribological testing of compressor contact interfaces at very high environmental pressures up to 13.8 MPa (2000 psi). These tests demonstrate the possibility of testing at very high pressures similar to the internal pressures of CO2 compressors.

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