Showing papers in "Journal of Chemical & Engineering Data in 1965"

Stabilization of monoethanolamine solutions in carbon dioxide scrubbers

Abstract: OF THE DISCLOSURE Aqueous monoethanolamine solutions which contain trace amounts of copper and iron compounds are used as absorber solutions for carbon dioxide in air purify ing systems when stabilized to aeration-oxidation by the addition thereto of equal amounts of the monosodium salt of N,N-diethanolglycine and tetrasodium ethylenedi amine tetraacetic acid which are in the range of from 4.8 to 8% by weight on the monoethanolamine content of the solutions. The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the pay ment of any royalties thereon or therefor. This invention relates to a method of stabilizing monoethanolamine to aeration-oxidation during use in aqueous solution as the absorbent in scrubbers for re moval of carbon dioxide from the air-atmosphere of con fined quarters, more particularly of nuclear submarines. Aqueous monoethanolamine has the property of absorb ing carbon dioxide from other gases, such as air and flue gas, under relatively cool conditions to form a solution containing amine carbonate and can be regenerated in whole or in part by heating the solution to release carbon dioxide therefrom. A particular application of aqueous monoethanolamine (MEA) is in the purification of the atmosphere of nuclear submarines. In this application, the submarine is equipped with an apparatus known as a scrubber which consists essentially of an absorber (tower) which contains the aqueous MEA for removal of carbon dioxide from the air of the submarine and means including heat exchangers and a stripper (reboiler) for regeneration of the used MEA soiution and for cooling the regenerated solution and recycling it to the absorber. In operation of the Scrubber System, the atmosphere in the submarine is puimped through the absorption tower containing the aqueous MEA and the resulting amine carbonate-con taining solution delivered to the heat exchangers which preheats it and then to the stripper where it is heated by boiling under pressure to cause release of carbon dioxide therefrom. This carbon dioxide is pumped over board. The regenerated MEA solution is cooled by pass ing through appropriate heat exchangers and returned to the absorber for further removal of carbon dioxide from the atmosphere of the submarine. The process of absorb ing, stripping, cooling and recycling is continued until the carbon dioxide content of the submarine's atmosphere has been reduced to an adequately lower level. The con centration of carbon dioxide in the atmosphere of nuclear submarines is maintained at about 1% by volume. In the operation of the carbon dioxide scrubbers aboard nuclear submarines, it is at present customary to employ aqueous 4 N monoethanolamine solutions in the absorber. However, the concentration of MEA in the solutions may vary somewhat up or down from 4 normal which repre sents a practical concentration for the absorber operation. 0

Hot gas ignition temperatures of hydrocarbon fuel vapor-air mixtures

Abstract: : Laminar hot air jets of 1/8- to 3/4-inch diameter were used to determine the hot gas ignition temperatures of various combustible vapor-air mixtures. The combustibles were n-hexane, n-octane, n-decane, a hydrocarbon jet fuel (JP-6), and an adipate ester aircraft engine oil (MIL-L-7808). Minimum ignition temperatures occurred at a fuel to air weight ratio of about 0.5 and were not greatly sensitive to variations of fuel concentration. Moderate variations of jet velocity also had little influence on these ignition temperatures. However, these temperatures decreased with increase in heat source dimensions (jet diameter). The hot gas ignition temperatures of the combustibles were not necessarily much greater than corresponding autoignition and wire ignition temperatures when the size of the heat source and the ignition criterion were the same. (Author)

Ternary Systems: Water-Acetonitrile-Salts

Abstract: A preliminary series of qualitative tests have shown that some salts produce two liquid phases, some produce one liquid phase, and some precipitated from the aqueous solution by the addition of acetonitrile. Table I shows the effectiveness of the salts survey. The ternary diagrams for water-acetonitrile-NazC03, water-acetonitrile-Na?S?03, water-acetonitrile-NazSO,, water-acetonitrile-Na citrate, and water-acetonitrile-(NH4)2S04 were determined in a laboratory air-conditioned to 25" C. In addition, the equilibria were reached and maintained in a water bath thermostatically controlled at 25" C. f 0.05" C. The well known cloud point method was used throughout in the determination of the binodal curves. Owing to the great volatility of acetonitrile a t room temperature, closed vials were utilized for the weighed components. Tie line data were obtained by preparing mixtures of known composition within the limits of the two-phase region, shaking mechanically to increase the rate of mass transfer and hasten the approach t o equilibrium, and allowing the two layers to separate, immersed in the 25" C. bath. A centrifuge was used occasionally when one phase showed a tendency to emulsify partially with the other. The two layers were analyzed for salt content by evaporation to dryness to constant weight. The method

High-temperature properties of cesium

Abstract: : Experimental results are presented for the density and vapor pressure of the liquid and for various saturation and super-heat properties of the vapor. A virial equation of state is advanced and is used thermodynamically to derive additional properties of the vapor. For example, enthalpy, entropy, specific volume, and specific heat are tabulated for some 1100 selected vapor states in the temperature range from 1250 to 2550 F and in the pressure range from 0.2 to 34.0 atm.

Partial Volumetric Behavior in Hydrocarbon Systems. n-Decane and Carbon Dioxide in the Liquid Phase of the n-Decane-Carbon Dioxide System.

Abstract: 62,579 (1958). Ibid., 63,753 (1959). Francis, A.W., “Physical Chemistry of the Hydrocarbons,” A. Farkas, Ed., Vol. I, p. 265, Academic Press, New York, 1950. Francis, A.W., “Liquid-Liquid Equilibriums,” Wiley, New York, 1963. Francis, A.W., U. S. Patent 2,389,250 (November 20, 1945). Francis, A.W., U. S. Patent 3,003,006 (October 3, 1961). International Critical Tables, Vol. 111, McGraw-Hill, New York, 1928. M i e , R.T., J. Res. Natl. Bur. Std. 13,95 (1934). Satteheld, C.N., Powell, J.H., Jr., Oster, E.A., Jr., Noyes, J.P., Ind. Eng. Chem. 47,1458 (1955). (19) Seidell, A., “Solubilities of Inorganic and Metal-Organic Compounds,” 3rd ed., Van Nostrand, Princeton, N. J., 1940. (20) Spall, B.C.,, Can. J. Chem. Eng. 1963, 79. (21) Terres, E., Riihl, G., Z . Angew. Chem. 47, 331 (1934); through Landolt Biirnstein-Roth-Scheel, “Tabellen,” Julius Springer, Berlin, Erg. IIIa, 672 (1935).