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T.P. 3082

PHASE EQUILIBRIA IN HYDROCARBON-WATER SYSTEMSI l l -The Solubility of Methane in Water

at Pressures to 10,000 PSIA

o. L. CULBERSON, GULF RESEARCH AND DEVELOPMENT CORP., HARMARVILLE, PA., AND J. J. McKETTA, JR.,MEMBER AIME, DEPARTMENT OF CHEMICAL ENGINEERING, THE UNIVERSITY OF TEXAS, AUSTIN, TEX.

ABSTRACTExperimental and smoothed data are pre,ented for theO'olubility of methane in water for temperature, of 77. 100.

160, 220, 280, an d 340'F at pre3sures to 10,000 psia.The minimum solubility phenomenon exists within this tem

perature range to pre"ures of 10.000 psia.

INTRODUCTIONThe study of hydrocarbon-water systems has been extendedto the d.etermination of the 80lubility of methane in waterat pressures to 10.000 psia. The experimental apparatus. an dthe technique, are the same as that previously reported.I.'In the determination of the solubility of methane in water,only two phases were present at temperature, between 100

and 340'F. the"e being the vapor phase an d the water-richliquid phase. The determinations involved the agitation ofmethane and water in an equilibrium cell, withdrawal of asample from the liquid phao;e, an d the analysis of the sample.The experimental values determined in this manner are presented in Table I an d in Fig. 1.

Since experimental and analytical techniques have improvedsince the initial experiments with this equipment. it wasdecided to repeat the 77'F iwtherm determination,.' Fig. 1shows that the individual results for this isotherm are much

lReferences given a t en d of paper.Manuscript received in th e office of th e Petroleum Branch Nov. 16. 1950.

,wex:::>II )II )wex:a.

01XlO '3e "", "N,", 1/6 flI} rff5 (// Vi /177 /I jI/), !31XlO2 ~ ) ~ VIr!w~ VIe /760 0 ~~ v: 1/500 ~ ~ ~4

~ l /300W //V/2 ..". -77f.e -100F.4!> -16001'B -220FX -280F

100 -340F0.2 0.3 0.5 0.7 1.0 2.0 3.0 5.0 70 10.0

MOL FRACTION METHANE X 103FIG. 1 - SOLUBILITY OF METHANE IN WATER AT CONSTANT TEMPER.ATURE.

Vol. 192,1951 PETROlEUM TRANSACTIONS, AIME 223

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T.P. 3082 PHASE EQUILIBRIA IN HYDROCARBON-WATER SYSTEMSIII - The Solubility of Methane in Water at Pressures to 10,000 PSIATable I - Experimental Values fo r the Solubility of Methane in Water

Pressure: LbjSq In . Abs (psia)77F 100F 160Fpsia MF CH. psia MF CH, psia MF CH,

341 0.000497 330 0.000440 331 0.000340459 0.000717 477 0.000619 467 0.000470659 0.001000 664 0.000839 659 0.000632934 0.001317 950 0.001123 943 0.0009091290 0.001678 1270 0.001440 1320 0.0011831930 0.002235 1900 0.001890 1880 0.001500

2495 0.002585 2575 0.002290 2555 0.0019243515 0.003110 3535 0.002760 3535 0.0023854810 0.003660 4910 0.003330 4925 0.0027706440 0.004170 6525 0.00391 6525 0.003427795 (0.004370) 7870 0.00417 8220 0.003759300 (0.004450) 9895 0.00465 9865 0.00424

more nearly consistent than the data previously reported.'In Table I the data for the 77F isotherm are in parenthesesfor pressures above 6,800 psia. These parenthetical values arenon equilibr ium solubilities de termined when the liquid phaseco-existed with vapor and hydrate phases. The original purpose of this investigation was the study of vapor-liquid equilibrium. Fo r those pressures at which the hydrate formed,samples of the liquid phase nevertheless were taken. However,the attainment of equilibrium in hydrate systems is a slow

I1,I160,000 I150,(00 \I

./' : ~ , / "V V dcP.......--/~- V'2.r::f:8-.- ~ -I---~ -60 0:>00

MATERIALSThe water used was distilled, and deaerated by boilingbefore use. The methane used had th ; following compositionas analyzed by the Gulf Oil Corp.: nitrogen, 0.27 per cent;

carbon dioxide, 0.21 per cent; methane, 98.72 per cent; ethane,0.60 per cent; propane, 0.13 per cent; butanes plus, 0.07 percent.

ACKNOWLEDGMENTThe writers wish to express their appreciation to the GulfOil Corp. for extending the Gulf Oil Fellowship to Culbersonfor this investigation. The Phillips Petroleum Co. generouslysupplied the pure grade methane used in this work.

REFERENCESo60 100 140 180 220 260TEMPERATURE, oF. 300 34 0 1. Culberson, O. L.. and McKetta, J . .T.: Trans. AIME (1950)FIG. 5 - VOlUMETRIC SOLUBILITY OF METHANE IN WATER.

per barrel (42 gal) of liquid. This has been done in Fig. 5.The volume of methane is referred to 60F and 14.7 psia. Thecurves for the various pressures have the same characteristicsas those of Fig. 3, since the data for Fig. 3 were multiplied by7,370 to obtain the data for Fig. 5. In both Figs. 3 and 5the hydrate region is indicated on the basis of observationsof the authors, but primarily upon the work of Kobayashi andKatz."

189, 319.2. Culberson, O. L., Horn, A. B., and McKetta, J. J.: Trans.

AIME (1950) 189, 13. Dodson and Standing: AP I Drill. and Prod. Prac. (1944)173.4. Frost and Deaton: Oil and Gas Jour. (1944) 45, No. 12,1708.5. Katz, D. L.: Texas A&M Eng. Exp. Sta. Bulletin 114 (1949)30.6. Kobayashi and Katz, D. L.: Trans. AIME, T.P. 2579(March, 1949).7. Winkler: Z. physik. Chem. (1899) 9, 171. * * *

226 PETROLEUM TRANSACTIONS, AIME Vol. 192, 1951