Phase Equilibria in Hydrocarbon Systems Methaneân-Butane System

Phase Equilibria in Hvdrocarbon Svsterns J

J

Methane-n-Butane System in the Gaseous and Liquid Regions' B. H. SAGE, R. A. BUDENHOLZER, AND w. N. U C E Y California Institute of Technology, Pasadena, Calif.

From these primary data the partial volumetric behaviors of methane and nbutane were calculated throughout the single-phase region a t seven temperatures between 70' and 250° F. The partial enthalpy and the fugacity of these components were computed as functions of state for the greater part of the gaseous region. The partial thermodynamic behavior of each component is recorded in tabular form. Diagrams illustrating the behavior of this binary system are included.

The specific volume of each of twenty-four mixtures of methane and n-butane was determined as a function of pressure and temperature at pressures as high as 3500 pounds per square inch throughout the temperature interval between 70' and 250' F. These experimental results were interpolated to even values of pressure and composition and are presented in tabular form. Derived values of the isothermal enthalpypressure coefficient for several of the mixtures are recorded.

mixtures of methane and ethane (IS) at temperatures from 70" to 250" F. Data relating to the volumetric behavior in the liquid region of several binary systems containing methane were reported (IS). The measurements of Kay (3) upon the ethanen-heptane system included volumetric data relating to the coexisting phases, but the work was not extended into the single-phase regions. Information concerning the volumetric behavior of binary and ternary systems is of value in generalizing the phase behavior of the more complex systems which are of industrial interest. For this reason the volumetric and phase behavior of the methane-n-butane system was investigated in detail a t temperatures between 70" and 250" F. and a t pressures up to 3000 pounds per square inch (pressures in this paper are expressed in pounds per square inch absolute). Values of the volume, composition, and fugacity of the coexisting liquid and gas phases in this system (11), as well as Joule-Thomson coefficients for the gas phase a t pressures below 1500 pounds per square inch are available (1). In the present paper the volumetric behavior in the liquid and gas regions is recorded throughout the above-mentioned ranges of temperature and pressure for a systematic series of mixtures covering the composition interval from pure methane to pure n-butane. Throughout this discussion the terms "volume", "enthalpy", etc., will designate the volume and enthalpy of a unit weight system. The methods and apparatus were essentially the same as those employed in earlier investigations (11, 14,16). I n gen-

XPERIMEKTAL information relating to the volumetric behavior of binary hydrocarbon systems in the liquid or gaseous regions is scarce. Keyes and Burks (4) investigated the behavior of several mixtures of methane and nitrogen at elevated pressures in the gaseous region. Information is available concerning the behavior of gaseous

E

I O 0

0.95

0.90

$ I1 N

0.85

0.80

I

250

500 PRESSURE

I 750

LBS. PER

I 1000

I

I

1250

SO. IN.

FIGURE 1. EFFECT OF PRESSURE UPON THE COMPRESSIBILITY FACTOR OF A GASEOUS MIXTURE CONTAINING 0.6992 WEIGHT FRACTION METHANE

1This is the thirty-second paper in this series. peared during 1934-40, inclusive.

1262

Previous articles ap-

SEPTEMBER, 1940

INDUSTRIAL AND ENGINEERING CHEMISTRY

PRESSURE

L0S PER SQ. IN.

FIGURE2 . TYPICAL EXPERIMENTAL RESULTSFOR A LIQUID MIXTURE COXTAINING 0.1513 WEIGHT FRACTIOX METH~NE

eral, the accuracy of measurement was comparable to that obtained in these studies although numerous refinements in operation were made which increased the precision of measurement markedly. The methane and n-butane employed were the same materials used in the study of this binary system in the two-phase region ( 1 1 ) . At 100' F. the volumetric behavior of the methane was in excellent agreement (0.1 per cent) with the data of Kvalnes and Gaddy (5).

1263

Figure 3 illustrates the general nature of the volumetric behavior of this system. The volume of the methane-nbutane system a t 160' F. is presented as a function of composition and pressure. The state corresponding to the maximum weight fraction of methane for the existence of two phases is designated by n'. The latter state corresponds to the cricondentherm or the maximum temperature for the existence of two phases in a system of fixed composition. The variation in the compressibility factor with composition a t a temperature of 160" F. is presented in Figure 4. These data show an increasing rate of deviation from the perfect gas behavior with a n increase in the quantity of n-butane a t constant pressure and temperature. The variation in the compressibility factor of the dew-point gas with composition is also indicated on Figure 4. The same information is presented in Figure 5, but the residual volume (2) illustrates the behavior. Figures 3, 4, and 5 illustrate different graphical methods of presenting the same volumetric data. Figure 3 has the advantage of giving volume values directly, but from Figures 4 and 5 more accurate values may be obtained. Values may be obtained from Figure 4 with about the same percentage accuracy at all pressures. On the other hand, Figure 5 gives much greater percentage accuracy of reading a t the lower pressures. Points interpolated to even pressures from the directly measured values a t 160' F. are indicated by circles in Figure 4. I n some cases these data indicate a slightly larger disagreement from the smooth values than would be anticipated from a consideration of the estimated uncertainty in the primary variables. Except in a few instances the disagreement from the smooth data was less than 1 per cent while the average deviation of the experimental data in the gaseous region was 0.25 per centi. The values indicated in Figure 4 for pure methane and n-butane were obtained from the measurements of Kvalnes and Gaddy (6) and a study reported in this series (15). The agreement of these two independent sets of

Experimental Results A typical set of experimental results in the gaseous region is shown in Figure 1. The compressibility factor is depicted as a function of pressure for each of several temperatures for a mixture containing 0.6992 weight fraction methane. The experimental measurements for this mixture were not carried to pressures below 300 pounds per square inch, and the curves extending to the lower pressures were obtained by appropriate interpolation from experimental work upon other mixtures. The precision obtained for these results is within the uncertainty involved in the measurements of the individual variables. A similar set of data in the liquid region is presented in Figure 2, where the volume is shown as a function of pressure and temperature for a mixture containing 0.1513 weight fraction methane. The density of the experimental data shown in this diagram is typical of that obtained for the other mixtures in the condensed liquid and critical regions. It appears to be adequate to establish the behavior within the absolute uncertainty of the measurements. Fourteen mixtures were investigated in the gaseous region, and ten were studied primarily in the liquid region. Under some conditions these mixtures were above their critical temperatures.

0 90

0 80

0 70

5 U

0" 080 I-

2 aso

1 Y

040

-

Y

* 030 0 20

0 10

010

020

030

040 WEIGHT

050 FRACTION

060

070

000

O W

MFTHANE

FIGURE 3. SPECIFIC VoLrralE-Co\fPOSITIov DIAGR-IV 4T 160' F.

El

.-

crE

SEPTEMBER, 1940


1265

tainties greater than 0.6 per cent except in the immediate vicinity of the phase boundary where the uncertainty is somewhat larger. 0.90 I n Table I1 the volume in the liquid and critical regions is recorded as a function of 0.80 pressure, temperature, and composition. The values in parentheses are bubble-point pressures except those marked b , which are the 0.70 retrograde dew-point pressures. For the most part these data slightly overlap the states covered by the compressibility factors re0.60 corded in Table I, in order that the two sets c n of data may be compared more easily. It is 2 0.50 believed that the volumes in the liquid phase 1 do not involve uncertainties greater than 0.5 N per cent except in the immediate vicinity of 0.40 the critical state, where they become somewhat larger. The behavior of most materials is somewhat a30 simpler when volume is treated as an independent variable. Figure 7 illustrates the nearly 0.20 linear variation of pressure with temperature under isochoric conditions in the single-phase regions for a mixture containing 0.40 weight 0.10 fraction methane. Within the two-phase regions the isochors would exhibit appreciable curvature without showing rapid changes in this curvature even in the vicinity of the w w n r FRACTION METHANE critical state. FIGURE1. COMPRESSIBILITY FACTOR-COMPOSITION DIAGRAM AT 160" F. I n many engineering calculations i t is desirable to evaluate the effect of pressure upon the enthalpy of the system. Figmeasurements with the present data was an added indication ure 8 shows the variation in the enthalpy-pressure coefficient of the relatively small absolute uncertainty of the measure( b H / d P )T , n with composition for the methane-n-butane system for several pressures, a t 160" F. This coefficient is ments. The effect of composition upon the specific volume of the finite a t infinite attenuation, which is in accordance with reliquid phase a t 160" F. is shown in Figure 6. The points sults obtained from Joule-Thomson measurements ( I ) . shown mere interpolated directly from the experimental reThe latter data mere employed in establishing these coefficients a t the lower pressures, while the coefficients a t the sults without smoothing with respect to temperature. The agreement of the data a t other temperatures is similar to that shown in Figure 6. I n this region the average deviation of the interpolated points from the smooth curves a t all the temperatures was 0.18 per cent, which 0.14 is somewhat better than would be anticipated from the estimated uncertainty of the primary measurements. 0.14 It was not feasible to tabulate the experi5 mental results directly since they were obL tained a t random pressures and compositions. E 0.12 The data in both of the single-phase regions c have been interpolated graphically by residual 3' 0.10 methods t o even values of the pressure and composition. The measurements a t the lower Y pressures and higher weight fractions of 3 OD8 methane indicate fair agreement with Joule9 Thomson data ( I ) . The values recorded in uthis region represent critically chosen quan8 0.06 P VI tities based in part upon the Joule-Thomson -1 data. The results for the gas phase are 0.04 recorded in Table I, where the compressibility v) a factor-i. e., the ratio of the actual specific volume to the specific volume of a perfect gas 0.02 of the same composition-is presented as a function of pressure, temperature, and composition. Information concerning the behavior of the dew-point gas at several comW E I G H 1 F R A C T I O N METHANE positions is included in this table. It is believed that these data do not involve uncerFIGURE 5 . RESIDUAL SPECIFIC VOLUME-COMPOSITIOX DIAGRAM AT 160' F. 1.00

3


1266

VOL. 32, NO. 9

estimation of the residual partial volume of each of the components of this binary system from the residual volume of the mixture. I n the case of the liquid phase the partial volume 0.05 5 may be evaluated conveniently from the volume of the mixture by the direct application of this method. Experimental information concerning the phase behavior of mixtures of methane and nbutane was made available recently (11). These data, together with the information submitted in this paper, suffice to establish the partial volumetric behavior throughout the single-phase regions a t pressures u p to 3000 pounds per square inch in the temperature interval between 70" and 250" F. Residual methods were employed in the gaseous regions while the direct evaluation of the partial volume was utilized in the liquid and critical regions. The results of these calculations for each of the components were independently smoothed graphically. Tests for consistency may be applied to the partial volumes of the components established in this fashion in order to obtain an indication of the precision of the I I I I I 0.30 calculation of the partial volumes from the 0.05 0.10 0.15 0.20 C experimental volumetric data. However, it is WEIGHT FRACTION METHANE difficult to ascertain the absolute uncertainty FIGURE 6. EFFECT O F COMPOSITION UPON THE SPECIFIC VOLUME O F THE involved in the values themselves since they LIQUIDPHASE AT 160" F. result from a large number of graphical manipulations. Values of the residual partial volumes for methane and for higher pressures were determined from the volumetric data n-butane in the gaseous region for mixtures containing more by the use of the following relation: 0.6 weight fraction methane are recorded in parts of than ( d H / b P ) ~ , n= T(d_V/dT)p., - V (1) Tables I V and V, respectively. For the most part the partial volumes of one component computed from the recorded values The values of this coefficient are recorded as a function of presfor the other are consistent within 0.002 cubic foot per pound. sure, temDerature, and composition in Table 111. At the lower pressures uncertaintiesgreater than 3 per cent are unlikely, but at the higher pressures where the coefficient is small and represents the difference between two rather large experimentally determined quantities, the uncertainty may be as great as 5 per cent.

T

L

N

2500

Partial Thermodynamic Behavior I n the prediction of the thermodynamic behavior of multicomponent systems i t is advantageous to relate the behavior of the mixture of a system to properties of the individual components. The use of partial quantities (7) in this connection may afford a useful tool in such prediction from experimental information concerning the behavior of the same components in binary and ternary systems. The isobaric, isothermal partial value of any extensive property, G, for a component in a multicomponent system is related to the total value of this property for the system by the following way:

2

2000

$ W [L

a cd

1500

-I W [L v) 3

3

1000

[L

a

Gk = ( a g / d m k ) ~ , ~ . ~ ,

(2) 500

The relation between the residual partial volume (12) and the residual volume is indicated in the following equation: 100

I30

I60

I90

220

TEMPERATURE 'F:

This relation is such that the method of Roozeboom (10) may be applied directly t o the

E'ICrZTRE 7.

PRESSURE-TEMPER.4TURE DIAGRAM FOR A MIXTURE CONTAINIX(: 0.4 WEIGHT FRACTION METHANE

SEPTEMBER, 1940

INDUSTRIAL AND ENGINEERISG CHEZlISTRY

TABLE 11. Temp., a

F. 70

100

Pressure. Lb./Sq. In

-~ 0 025

B;,'. P. 300 400 500 600 800 1000 1250 1500 1750 2000 2250 2500 2750 3000

(903 3) (514 2) (716 I) 0.03030 0 03124 0 03227 . . . . . .. . .. ... ,. . , ..... . . . . . . . . . .. .. , . . , 0.03019 0.02998 0:03ii3 0.02978 0.03088 0 03210 0.02958 0.03062 0 03174 0.02940 0.03038 0 03143 0.02922 0.03017 0 03117 0 02903 0 02997 0 03092 0 02885 0 02976 0.03069 0 02868 0 02956 0.03048 0 02853 0 02938 0.03027 0 02838 0 02920 0 03007

.. ..

500

800 1000

1250 1500 1760 2000 2250 2500 2750 3000 160

B;: P. 400 500

Ann ...

800 1000 1250 1500 1750 2000 2250 2500 2750 3000 190

P. 500

B;:

600

800 1000 1250 1500 1750 2000 2250 2500 2750 3000 220

BU: P. 600 800

1000 1250 1500 1750 2000 2250 2500 2750 3000 250

B;: P. 800 1000 1250 1500 1750 2000 2250 2500 2750 3000

. . . . .. ..

:

600 800 1000 1250 1500 1750 2000 2250 2500 2750 3000

400 500 600

. .... .. ..,

0 030i8 o'o3ik 0.03039 0 03148 0,03020 0.03116 0.03001 0.03090 0.02982 0.03067 0.02963 0.03047 0,02945 0.03027 0,02928 0 03009 0 02911 0.02990

..

BU: P.

. . . ... . . . . ... .

.....

300 400

METHANEAND n-BUT.INE

Sp Vol (Cu Ft /Lb ) with Weight Fraction Methane as Follows 0 100 0 125 0 150 0 200 0 250 0 300 0 400 0 503 0 1603 0 700 0 050 0 075 (1893) (1924)b (1867)b (160O)b (1745) (460,s) (645,4) (819) (1393) (1604) (976) (1122) 0 02902 0 02984 0 03072 0 03167 0 03273 0 03518 0 03804 0 04135 0 05030 0 OB450 0 08441 0 1242

0.02899

Bu. P.

130

SPECIFIC VOLUMES FOR MIXTURES OF

1267

.

(335 0 ) (569 6) (784.0) 0,03061 0.03164 0 03280 . . . .. 0.03052 . . . . . . . ... . . .. . 0 03041 0.03030 0.03162 0.03010 0.03136 0:03i77 0.02992 0.03112 0.03244 0.02970 0.03084 0.03206 0,02948 0.03057 0.03173 0.02928 0.03032 0.03142 0.02907 0.03009 0.03114 0.02889 0.02985 0.03087 0.02872 0.02963 0.03062 0,02854 0.02943 0.03039 0.02837 0.02924 0.03017

..... .. . . . .. . . ...

. . ... , . . .. .. . ..

.

... ,.

..... ..... 0.03255 0.03221 0 '0ii9l 0 03189 0.03437 0,03162 0 03387 0.03137 0.03346 0.03115 0,03312 0.03095 0.03287 0 03076 0 03265

.. . . , . , .. , ., .....

.. .. .. . , . , .....

.

(1565) (1736) (979 5 ) (1153) (1308) (1833)- (1870)b (1712)b 0 03404 0 03540 0 03696 0 04082 0 04647 0 05135 0 06800 0 09744 .... ,.... .... .....

..... 0.03398 0.03346 0.03300 0.03261 0.03227 0.03196 0.03168 0.03143 0.03121

..... . ... 0.03508 0.03447 0 : 03632 0,03397 0.03557 0.03353 0.03496 0.03316 0.03448 0.03282 0.03410 0.03253 0.03374 0 03225 0 03340

,....

....

,....

.....

...

0 ' 0396s 0.03846 0 03761 0 03697 0 03645 0 03597

0.04636 0.04336 0.04184 0.04066 0,03967 0.03884

,.... .. ..

.....

..... .....

0 04910 0 04671 0 04487 0 04343 0 04219

(696.5) (848 6) (1111) (1276) (1409) (1620) (1698) (1645)b 0 03547 0.03721 0.03920 0 04144 0.04397 0.05043 0.05991 0 07570 . , . .. .. . , . ..... ..... . . ..... ..... . . .. . . ... . ..... ..... ..... ..... . . 0.03521 ..... ..... .. .. ..... .. . 0.03470 0 03G58 ..... ..... ..... .. . 0.03410 0.03601 0.03844 ..... ..... , . . . 0.03356 0.03530 0.03728 0'03Q72 0.04286 . . . . . 0.03307 0.03469 0.03645 0.03846 0.04092 0.04835 0 : 05860 0 07030 0.03265 0.03416 0,03580 0 03757 0,03968 0.04541 0.05299 0 06219 0 03230 0.03369 0.03523 0 03682 0.03865 0.04343 0 04948 0 0.5658 0.03200 0.03330 0.03470 0 03613 0.03779 0.04203 0.04715 0 05285 0.03170 0.03293 0.03420 0 03557 0.03708 0.04088 0,04529 0 05030 0 03141 0 03258 0.03379 0 03505 0.03647 0.03980 0.04380 0.04539

.....

,....

0'0i263 0 04052 0 03908 0 03804 0 03720 0 03650 0 03586 0 03527

0.04400 0 04188 0 04043 0 03923 0.03825 0.03747 0 03580

,....

.....

..... . ... 0.04878 0.04544 0.04328 0.04164 0.04036 0.03933 0.03844

(1173) (1255) (1242)b 0 05263 0.05919 0 07020

.....

0.05059 0.04562 0.04243 0.04050 0.03931 0.03833 0.03750 0.03675

.....

..... 0.05152 0.04664 0.04375 0.04200 0.04064 0.03951 0 03860

0 : 06983

0 05851 0 05221 0 04775 0 04507 0 04321 0 04170 0 04053

..... .....

.....

.....

.....

0.08420

0 05132 0.06556 0 04860 0.06040 0.05681 0 04660 0 04499 0.05396

0.05500

0.05036 0.04733 0.04525 0.04362 0.04220

.....

.....

..... .....

0.07968 0 06660 0.05923 0.05437 0.05100 0.04851 0.04674

..... 0.08013 0.06990 0.06289 0.05800 0.06456 0.05199

.. .. ,. .. .. ..... .....

.....

0.06400 0.05829 0.05450 0.05176 0 04952

o o5iio 0.07288

:

(973.1) (1167) (1307) (1422) (1517)b (1349)b 0.04083 0.04360 0.04664 0 05030 0.06204 0.08970 ... .. ..... ,.... ..... .....

.

.....

(1810)b (1689)b 0.05884 0 08773 .....

(449.8) 0.03397 0.03386 0,03363 0.03320 0.03280 0.03234 0.03193 0.03156 0.03126 0.03100 0.03076 0.03052 0 03029

(600, 0) (824.8) (1024) 0.04070 0.04386 0.04768 ..... 0.03893 . . . . . 0.03760 0,04146 . . . . . 0.03640 0.03921 0.04392 0,03554 0.03777 0.04101 0,03481 0.03668 0.03913 0.03418 0.03583 0.03792 0.03373 0.03823 0.03706 0,03338 0 03473 0.03633 0,03300 0.03426 0.03569 0.03262 0.03375 0 03.510

., .,.

. . . .

. . . . .. .

(1796) (1906) (1888)h (1696)b (1074) (1228) (1485) (1672) 0 03337 0 03463 0 03775 0 01167 0 04605 0.05820 0 0748,i 0.10744 , , . .. .. .., . ... ..... ..... ... . .. .. .. .. ,, . .. .. .., , . . . ,.... ..... .. .. . . ... .. .. ..... ..... ..... ..... . .. , . . .. , . . . .. . .. ..,.. .. .. .. . . .. . .. .. . ..... .. .. . . , .. . .. .. .. 0 03298 0 03455 , . ., ..... 0 03256 0 03385 0'03767 . . . . . 0.10395 0 03223 0 03337 0 03660 0.04120 . . . , . 0 03194 0 OR302 0 03586 0.03979 0.04421 0'05610 0 : 07220 0.08966 0 03168 0 03272 0 03533 0.03881 0,04266 0 05214 0.06461 0.07912 0 03144 0 03246 0 03493 0,03808 0.04180 0.04931 0.05934 0.07158 0 03121 0 03220 0 03456 0.03746 0.04064 0 04740 n 05575 o 06634 0 02100 0 03196 0 03420 0,03687 0.03994 0.04607 0 08340 0.06263

(1228) (1377) (1611) (1757) (628.3) (848.5) (1049) 0.03337 0 03477 0 03629 0 03802 0 04001 0 01484 0 05081 ,.... ... . ..... ..... ..... 0.03302 ... . . .. ... . 0.03264 0103441 0.03224 0.03382 0'03%8 0'03790 ..... ..... ..... 0.03192 0.03333 0 03490 0 03664 0 03908 0.03162 0.03294 0 03434 0.03582 0 03775 0,04339 . . . . . 0.03133 0.03258 0 03387 0.03525 0 03687 0.04160 0.04799 0.03104 0.03221 0 03345 0.03477 0 03627 0.04039 0.04663 0.03077 0.03188 0 03308 0 03433 0 93574 0.03948 0 04386 0.03053 0.03160 0 03274 0.03394 0 03523 0 03862 0.04247 0 03034 0.03134 0 03243 0.03356 0 03473 0 03780 0 04130

0:04061 0.03888 0.03771 0.03680 0.03607 0.03544 0.03489 0.03437 0.03387

. . . ..

.. . .. . .. .. . . . . .. . . . .. , . . .

..... ., , .

(378.2) 0.03209 0.03206 0.03189 0.03173 0.03142 0.03115 0.03085 0.03060 0.03038 0.03014 0.02991 0.02969 0.02950 0.02936

(762.0) 0.03848 , . ... 0,03829 0.03730 0.03626 0.03542 0.03476 0.03423 0.03380 0.03340 0.03299 0.03257

,, ,,,

Figures in parentheses indicate Q

0.07546 bubble-point pres0.06404 sures (Bu. P.) In 0.05700 pounds per square 0.05227 inch. h Retrograde dew 0 04898 0.04672 point. 0.04498

..

.....

.....

0.09541 0,08259 0.07331 0.06671 0 05880 0.06210

.. . . . .... .... ,

..... .. ... ..... .. ...

.....


1268

1

r $

1

1

VOL. 32, NO. 9

This was ascertained by the integration of the following relation a t constant temperature and pressure :

0.04

(4)

e a

However, in the vicinity of dew point or a t very low weight fractions of the component in question, the discrepancies from Equation 4 are somewhat larger than the above-mentioned limit. 30attempt was made to reconcile the values with the K W restrictions imposed by Equation 4. a 0.02 The residual partial volumes for methane and for n-butane 3 in gaseous mixtures containing less than 0.5 weight fraction d methane are recorded in parts of Tables VI and VII, re2 0 . 0I 0 60 0 70 oao ago spectively. These data for the most part satisfy Equation 4 =a a50 with an uncertainty of about 0.0025 cubic foot per pound. I WEIGHT F R A C T I O N M E T H A N E However, in the vicinity of the two-phase region the uncerFIGURE 8. EFFECTOF COMPOSITION UPOX THE ENTHALPY- tainty is larger. The partial volumes for both of the cornPRESSURE COEFFICIENTS OF GASEOUS MIXTURES OF METHAXE ponentsin the liquid are listed in Tables VI11 and IX. AND n-BUTANE AT 160" F. The partial volume is -recorded in this instance since the perfect-gas reference volume employed in the evaluation of the residual partial volume given in Tables IV to VII, inclusive, is not suitable for use in the liquid region. TABLE 111. ISOTHERMAL ENTHALPY PRESSURE COEFFICIENTS FOR GASEOUS MIXTURESOF The variation in the residual partial volume of methane METHANE AND BUTANE with composition is presented in Figure 9 for several pressures Coefficient (B. T. C . per Lb./Lb. per Sq. In.) a t a temperature of 160" F. Similar information for nPressure, with Weight Fraction Methane as Follows: Lb./Sq. butane is shown in Figure 10. The rather complex behavior In. 0.60 0.70 0.80 0.90 1.00 indicated in the vicinity of the boundary of the two-phase Temperature, 70' F. region results from the sensitivity of the specific volume to 0.0357 0.0309 0.0282 0.0268 0.0263 0 small changes in environment a t these states. The agreement .... . . . . 0.0322 0,0309 0.0302 500 .... .... 0.0317 0,0300 0.0305 1000 of the data presented in Figures 9 and 10 with Equation 4 0.0288 0.0280 0.0287 1500 may be shown by graphical evaluation of the slopes of the 0:0274 0:0269 0.0246 0.0235 0.0250 2000 0.0167 0,0199 0.0203 0.0195 0.0203 2500 isobaric, isothermal lines on the two diagrams. 0.0097 0.0182 0.0154 0.0154 0.0150 3000 The effect of composition upon the partial volumes of Temperature, 100' F. methane and of n-butane in the liquid phase a t 160" F. is pre0.0244 0.0238 0.0323 0.0264 0.0258 0 sented in Figures 11 and 12, respectively. These figures indi0.0270 .... 0.0328 0.0298 0.0279 500 0.0298 0.0277 0.0269 .... 0.0324 1000 cate a gradual increase in the partial volume of methane with . . . . 0,0292 0.0272 0.0258 0.0284 1500 0 . 0 2 3 7 0.0224 0.0224 0.0254 0.0256 2000 an increase in its weight fraction. However, the partial vol0.0184 0.0203 0.0197 0.0188 0.0186 2600 ume of n-butane decreases with an increase in the weight frac0.0119 0.0142 0.0152 0.0152 0.0148 3000 a

-1

0.03

-3

&

Temperature, 130' F. 0.0235 0.0222 0 . 0 2 7 1 0,0252 0.0277 0.0254 0.0255 0.0237 0.0224 0.0210 0 , 0 1 8 8 0.0178 0,0149 0.0147

0.0215 0.0241 0.0237 0.0217 0.0195 0.0169 0.0142

Temperature, 160° F. 0 . 0 2 1 4 0.0202 0 . 0 2 4 6 0.0229 0 , 0 2 5 5 0.0232 0 . 0 2 3 8 0.0218 0 . 0 2 1 1 0.0196 0.0177 0.0168 0.0143 0.0140

0.0195 0.0218 0.0211 0.0193 0.0175 0,0157 0.0134

0.0214 0.0244 0,0255 0.0239 0.020s 0.0171 0.0134

Temperature, 190" F. 0.0195 0.0184 0.0225 0.0209 0.0234 0.0213 0,0221 0.0199 0.0196 0.0180 0.0166 0.0157 0.0135 0.0131

0.0179 0.0198 0.0189 0.0175 0.0161 0.0146 0.0126

Temperature, 220' F. 0.0194 0.0179 0.0169 0.0222 0,0208 0.0191 0.0236 0.0215 0.0195 0.0222 0,0204 0.0182 0.0195 0.0182 0.0166 0.0160 0,0154 0.0144 0.0126 0.0125 0.0121

0.0163 0.0181 0.0172 0.0158 0.0146 0.0133 0.0115

Temperature, 250' F. 0.0163 0.0154 0.0191 0.0175 0.0197 0.0179 0.0187 0.0166 0.0167 0.0151 0,0151 0.0141 0.0130 0.0116 0 . 0 1 1 3 0,0109

0.0148 0.0163 0.0156 0.0144 0.0134 0.0120 0.0103

0.0292 0.0348 0.0326 0.0286 0.0240 0.0184 0.0130

0,0259 0.0297 0.0299 0.0274 0.0237 0.0196 0.0145

500 1000 1500 2000 2500 3000

0.0267 0.0307 0.0304 0.0271 0.0226 0.0180 0.0134

0.0236 0.0269 0.0276 0.0257 0,0221 0.0184 0.0141

0 500 1000 1500 2000 2500 3000

0.0245 0.0277 0.0285 0.0257 0.0214 0.0174 0.0132

0 500 1000 1500 2000 2500 3000

0.0224 0.0257 0.0268 0.0244 0.0207 0.0168 0.0126

0 500 1000 1500 2000 2500 3000

0.0205 0.0241 0.0253 0.0234 0.0202 0.0161 0.0118

0 500

1000 1500 2000 2500 3000 0

0.0176 0,0205 0.0218 0,0208 0,0183

WEIGHT

FRACTION

METHANE

PARTIAL SPECIFIC FIGURE 9. EFFECTO F COMPOSITIOK UPON THE RESIDUAL VOLUMEOF METHANEIN THE GASPHASE AT 160" F.

INDUSTRIAL AKD ENGINEERING CHEMISTRY

SEPTEMBER, 1940

TABLE Iv. Temp., O

Pressure,

F.

Lb./Sq. In.

70

D. P. 0 100 200 300 400 500 600 800 1000 1250 1500 2000 2500 3000

100

D. P.

130

100 200 300 400 500 GOO 800 1000 1250 1500 2000 2500 3000 0 100 200 300 400 500 600 800 1000 1250 1500 2000 2500 3000

160

n 100 200 300 400 500 600 800 1000 1250 1500 2000 2500 3000 0 100 200 300 400 500 600 800 1000 1250 1500 2000 2600 3000 0 100 200 300

190

220

400

250

-

500 600 800 1000 1250 1500 2000 2500 3000 0 100 200 300 400 500 600 800 1000 1250 1500 2000 2500 3000

1269

PARTIAL THERMODYNAMIC PROPERTIES" O F bfETHANE I N THE GAS PHASE O F THE METHaNE-n-BUTANB PO

-

2

0,016 0.0319 0.0236 0.016

....

.... .... .... .... .... .... .... .... .... .... 0.0126 0,0294 0.0229 0.01s1 0.0150 0.0132

....

.... .... .... .... ....

.... .... ....

0 0269 0.0248 0.0232 0.0219 0.0214 0.0213 0.0215 0,0225 0.0237 0.0252 0.0258 0.0240 0.0209 0.0176 0.0245 0.0238 0.0232 0.0227 0,0222 0.0218 0,0215 0.0208 0,0202 0.0193 0.0186 0.0171 0.0146 0.0127 0.0222 0.0218 0.0214 0.0210 0.0206 0.0202 0.0197 0.0186 0.0174 0.0159 0.0144 0.0121 0.0100 0.0086 0,0198 0.0195 0.0191 0.0187 0.0182 0.0177 0.0171 0.0159 0.0147 0.0131 0.0116 0.0085 0.0064 0.0052 0.0176 0.0171 0.0166 0.0160 0.0155 0.0150 0.0146 0.0135 0.0126 0.0114 0.0102 0.0078 0.0052 0.0026

GO-

-0.70-

-

--

--

Weight Fraction Methane as Follows: 0s0-090-

SYSTEM

-

HI 5: 3

.. .. .. .. .. .. .. .. .. .. .. .. ..

zi:3 19.9 18.3 16.3 14.1

.. .. .. .. .. .. .. ..

..

37.7 36.7 i35.7 34.6 33.3 31.9 30.2 26.3 21.7 15.4 8.6 -5.2 -18.6 -31.1 54.4 63.9 53.4 52.8 52.0 51.1 50.0 47.4 44.1 39.4 34.2 23.1 11.7 1.1 71.4 71.3 71.0 10.6 (0.1 69.4 68.6 66.6 64.2 60.6 56.5 47.4 38.0 29.2 88.9 88.8 88.6 88.3 87.9 87.3 86.6 84.9 82.9 79.9 76.6 69.2 61.4 54.2 106.7 106.6 106.3 105.9 105.5 104.9 104.2 102.7 100.8 98.2 95.3 89.1 82.8 77.0

0.9844 1.0000 0.9924 0,9868

.... .... ,... ., .. . ... . . .. . . .. .... .... .... . . ..

0 9768 1.0000 0.9931 0.9886 0.9833 0.9798

.... .... .... . .. . .. ,. .... .... .. .. ....

1 0000 0 9932 0.9872 0.9815 0.9762 0.9709 0.9679 0.9549 0.9438 0.9293 0.9144 0.8853 0.8594 0.8398 1.0000 0.9941 0.9885 0.9831 0.9778 0.9727 0.9676 0.9578 0.9483 0.9370 0.9264 0.9667 0.8894 0.8747 1.0000 0.9949 0.9900 0.9852 0.9805 0.9759 0.9714 0.9628 0.9548 0.9458 0.9376 0.9234 0.9118 0.9022 1.0000 0.9957 0.9915 0.9874 0.9831 0.9795 0.9757 0.9686 0.9621 0.9547 0.9482 0.9378 0.9303 0.9245 1.0000 0.9963 0.9929 0,9894 0.9861 0.9828 0.9799 0.9742 0.9688 0.9626 0.9578 0.9496 0.9431 0.9360

0.0288 0.0366 0.0340 0.0318 0.0303 0.0293

....

.. , , .. . . .... .... .... .... .. . . .... 0 10327 0.0293 0.0277 0.0275 0 0281 0.0292 0.0308 0 0342 0.0360 0.0366 0.0344 0.0298 0.0252 0.0203 0.0290 0.0286 0.0282 0.0279 0.0278 0.0277 0.0278 0.0382 0.0286 0.0284 0.0273 0.0248 0.0207 0.0160 0.0256 0.0265 0.0254 0.0252 0.0251 0.0250 0.0248 0.0244 0.0239 0.0232 0.0224 0.0201 0.0164 0.0124 0.0227 0.0225 0.0223 0,0221 0.0219 0.0216 0.0213 0.0207 0,0201 0.0192 0.0183 0.0161 0.0128

0.0090

0.0199 0.0197 0.0194 0,0191 0.0188 0.0186 0.0182 0.0175 0.0168 0.0160 0.0150 0.0128 0.0097 0.0064 0,0180 0.0175 0.0170 0.0165 0.0161 0.0157 0.0153 0.0146 0.0140 0.0131 0.0122 0.0098 0.0068 0.0036

..

0.9583 1.0000 0:OiOG 0.9901 0.0398 0.9807 0.0398 0.9723 0.0404 0.9639 0.0411 . . . . 0.0418 .... 00422 . , . . 0.0422 . . 0.0414 . . . . 0.0400 .. 0,0382 . . .. 0.0336 ... 0,0284 0.0226

5,3 3.2 1.0 --1.3 -3.7

.. .. .. .. .. .. ., ..

1:oOoo

2i:3 19.5 17.5 15.4 13.2 11.0 8 7 3.8 -1.1 -7.5 -13.8 -26.1 -37.6 -48.0 37.7 36.0 34.2 32.2 30.2 28.1 26.0 21.5 16.9 11.0 5.1 -6.2 -16.6 -25.9 54.4 52.8

51.1 49.4 47.5 45.6 43.7 39.6 35.4 30.0 24.7 14.5 5.1 -3.3 71.4 70.0 68.4 66.8 65.2 163.4 61.6 58.0 54.2 49.4 44.6 35.3 26.9 19.4 88.9 87.5 86.2 84.7 83.2 81.6 80.0 16.7 73.3 69.0 64.7 56.5 49.0 42.3 106.7 105.5 104.2 102.9 101.6 100.1 98.7 95.8 92.8 89.0 85.2 77.9 71.2 65.2

0 residual partial specific volume, cubio foot per pound; mole fraction of methane.

0.9887 0.9782 0,9672 0.9561 0,9450 0.9338 0.9118 0.8905 0.8663 0.8416 0,7999 0.7656 0.7385

0:6i55 0.0349 0.0349 0.0353 0.0359 0.0362 0.0363 0.0362 0.0357 0.0345 0.0328 0.0287 0.0239 0.0187 0.0307 0.0307 0.0307 0.0307 0.0307 0.0306 0.0305 0.0301 0.0296 0.0287 0.0277 0.0248 0.0195 0.0154

2i:3 19.1 16.8 14.4 12.0 9.5 7.0 1.9 -3.2 -9.6 -15.7 -26.8 -36.5 -45.2 37.7 36.7 33.6 31.4 29.1 26.8 24.5 19.7 14.9 9.0 3.3 -7.2 -16.4 -24.4

0.9906 0.9812 0.9718 0.9623 0.9530 0.9439 0.9263 0,9090 0.8883 0.8658 0,8339 0.8050 0,7824 1.0000 0.9923 0.9855 0.9768 0.9693 0.9618 0.9544 0,9398 0.9268 0.9080 0.8927 0.8633 0,8396 0.8212

0.0366 0.0366 0.0367 0.0366 0.0366 0.0365 0.0359 0.0352 0.0338 0.0319 0.0275 0.0228 0.0179 0.0317 0.0316 0.0314 0.0313 0.0312 0.0310 0.0308 0.0304 0.0297 0.0285 0.0269 0.0231 0,0190 0.0147

0.0266 0.0265 0.0264 0.0262 0.0261 0.0260 0.0259 0.0256 0.0253 0.0246 0.0235 0.0205 0.0165 0.0122 0.0230 0.0228 0.0227 0.0225 0.0224 0.0222 0.0221 0.0218 0.0215 0.0208 0.0198 0.0169 0.0134 0.0093

54.4 52.5 50.6 48.6 46.6 44.5 42.4 38.1 33.8 28.4 23.1 13.3 4.7 -2.8

1.0000 0.9936 0.9873 0.9811 0.9748 0.9687 0.9626 0.9508 0.9391 0.9251 0.9117 0.8876 0.8681 0.8830

0.0272 0.0271 0.0270 0.0268 0.0266 0.0264 0.0262 0.0256 0.0250 0.0238 0.0224 0.0191 0.0157 0,0118

71.4 69.7 67.9 66.1 64.3 62.4 60.4 56.5 52.6 47.8 43.0 34.0 26.1 19.1

1.0000 0.9947 0.9895 0,9844 0.9793 0,9744 0.9694 0.9596 0,9500 0.9385 0.9276 0.9082 0,8924 0.8807

0.0233 0.0231 0.0230 0.0228 0.0226 0.0224 0.0221 0.0214 0.0207 0.0197 0.0185 0.0156 0.9121 0.0091

0.0200 0.0198 0.0196 0.0194 0.0192 0.0190 0.0188 0.0185 0.0181 0.0174 0.0164 0.0137 0.0104 0.0066 0.0173 0.0170 0.0167 0.0164 0.0162 0.0160 0.0158 0.0154 0.0149 0.0141 0.0132 0.0108 0.0077 0.0042

88.9 87.3 85.7 84.0 82.4 80.6 78.9 75.4 71.8 67.5 63.2 55.2 47.8 41.4 106.7 105.3 103.8 102.4 100.9 99.3 97.8 94.7 91.6 87.7 83.9 76.6 70.0 64.1

0.9956 0.9914 0,9871 0.9829 0.9788 0.9747 0.9667 0.9590 0.9496 0.9408 0.9253 0.9130 0.9046 1.0000 0.9964 0.9930 0.9894 0.9860 0,9827 0,9794 0.9730 0.9675 0.9594 0.9526 0.9406 0.9314 0.9256

.. .. . ....

..

0.9915 0.9834 0.9755 0 9680 0.9604 0.9528 0.9369 0.9195 0.8981 0,8776 0.8410 0,8107 0,7864 1.0000 0 9928 0.9866 0.9786 0.9717 0.9649 0.9581 0.9446 0.9311 0.9145 0.8994 0.8692 0.8444 0,8249 1.0000 0.9939 0.9878 0.9817 0.9758 0.9699 0.9641 0.9527 0.9417 0.9284 0.9157 0.8923 0.8728 0.8577 1.0000 0.9948 0,9898 0.9846 0.9796 0.9748 0.9699 0.9606 0.9517 0.9411 0.9309 0.9127 0.8976 0.8864 1.0000 0.9956 0.9914 0.9872 0.9831 0.9790 0.9751 0.9675 0,9602 0.9516 0.9435 0.9991 0.9177 0.9098 1.0000 0.9962 0.9927 0.9892 0.9858 0.9825 0.9792 0.9730 0.9673 0.9603 0 9540 0.9430 0.9317 0.9298

a

1:bbOO

5:3 2.9 0.4 -2.2 -4.9 -7.5 -10.2 -15.7 -21.3 -28.1 -34.6 -46.2 -56.4 -65.6

O:b434

0.0433 0.0432 0.0431 0.0429 0.0428 0.0426 0.0420 0.0412 0.0396 0.0376 0.0329 0.0272 0.0212

1:Oooo 010366

1.0000 0.0200

0.0199 0.0198 0.0196 0.0194 0.0191 0.0188 0.0181 0.0173 0.0162 0.0150 0.0126 0.0097 0.0064 0.0171 0.0168 0.0165 0.0161 0.0158 0.0154 0.0151 0.0143 0.0136 0.0127 0.0117 0.0097 0.0072 0.0040

= partial enthalpy, B. t. u. per pound.

i:3 2.7 -0.1 -2.9 -5.8 -8.7 -11.7 -17.6 -23.5 -30.7 -37.6 -49.9 -60.4 -68.8

1:0000 0.9879 0.9789 0.9640 0.9524 0.9409 0.9296 0.9077 0.8866 0.8616 0.8384 0.7977 0.7646 0.7390

0:oiis 0.0446 0.0444 0.0442 0.0439 0.0436 0.0432 0.0422

1:booo

54.4 52.4 50.4 48.3 46.1 43.9 41.7 37.3 32.9 27.5 22.3 12.8 4.5 -2.7 71.4 69.6 67.8 65.9 64.0 62.1 60.1 56.1 52.2 47.3 42.7 34.0 26.4 19.7

0.9901 0.9803 0.9707 0.9611 0.9517 0.9424 0.9243 0.9069 0.8863 0,8670 0.8330 0,8053 0.7836 1,0000 0.9921 0,9842 0.9763 0.9686 0.9610 0.9538 0.9388 0.9246 0.9077 0.8919 0.8640 0.8412 0.8234 1,0000 0.9934 0.9870 0.9806 0.9743 0.9681 0.9620 0.9500 0.9384 0.9247 0.9118 0.8893 0.8707 0.8564 1.0000 0.9946 0.9894 0.9842 0.9790 0.9740 0.9690 0.9593 0.9501 0.9392 0.9289 0.9109 0.8961 0.8850

o:i)i76 0.0374 0.0372 0.0371 0.0368 0.0366 0.0363 0.0355 0.0344 0.0329 0.0313 0.0274 0.0227 0.0176 0.0322 0.0320 0.0318 0.0315 0.0313 0.0310 0.0307 0.0299 0.0289 0.0275 0.0260 0.0227 0.0187 0.0145 0.0276 0.0274 0.0272 0.0270 0.0267 0.0264 0.0261 0.0253 0.0243 0.0229 0.0215 0.0185 0.0152 0.0115 0.0236 0.0234 0.0232 0.0230 0.0228 0.0225 0.0222 0.0213 0.0203 0.0190 0.0176 0.0149 0.0118 0.0087

88.9 87.2 85.6 83.9 82.2 80.5 78.7 75.2 71.7 67.3 63.1 55.3 48.3 42.0 106.7 105.2 103.7 102.2 100.7 99.1 97.6 94.5 91.4 87.6 83.9 76.8 70.4 64.7

1.0000 0.9956 0.9913 0.9870 0.9828 0.9786 0.9746 0.9667 0.9590 0.9503 0.9422 0.9281 0.9168 0.9086 1.0000 0.9964 0.9929 0.9895 0.9862 0.9830 0.9798 0.9737 0.9681 0.9614 0.9550 0.9444 0.9359 0.9303

0.0201 0.0200 0.0199 0.0197 0.0195 0.0192 0.0188 0.0179 0.0169 0.0157 0.0144 0.0117 0,0088 0.0060 0.0170 0.0169 0.0168 0.0166 0.0164 0.0162 0.0158 0.0150 0.0140 0.0127 0.0114 0.0088 0.0061 0.0033

2i:3 18.9 16.4 13.9 11.2 8.6

6.0

0.6 -4.8 -11.3 -17.5 -28.9 -38.6 -46.6

37.7 35.5 33.2 30.9 28.5 26.0 23.6 18.6 13.8 7.8 2.2 -8.2 -17.2 -24.8

0.0410

0.0394 0.0374 0.0327 0.0270 0.0211

5:3 2.9 0.2 -2.6 -5.9 -9.0 -13.0 -21.0 -28.8 -36.4 -43.7 -57.2 -68.6 -77.5

1:oooo 0.9872 0.9759 0.9628 0,9509 0.9394 0.9277 0,9056 0,8847 0.8600 0,8370 0,7964 0,7633 0.7377

2i:3 18.7 16.2 13.7 11.0 8.5 5.6 0.2 -5.1 -11.8 -18.2 -30.2 -40.5 -48.8 37.7 a5.3 33.0 30.6 28.3 26.1 23.5 18.8 14.1 8.3 2.7 -7.5

1:oooo 0.9901 0.9802 0.9703 0.9608 0.9514 0.9422 0.9242 0,9071 0.8871 0.8683 0,8349 0,8073 0.7859 1.0000 0.9919 0.9840 0.9760 0.9682 0.9607 0.9531 0.9386 0.9249 0.9084 0.8932 0.8660

-1 26 4.6 4

0.8261 0,8437

5 4 . 4 1.0000 5 2 . 2 0.9931 5 0 . 1 0.9867 48.0 0.9802 45.8 0.9738 43.9 0.9677 41.5 0.9613 3 7 . 1 0.9497 3 3 . 1 0.9384 2 7 . 9 0.9251 23.0 0.9128 13.7 0.8910 5 . 4 0.8731 -1.8 0.8592 71.4 1.0000 69.5 0.9946 67.6 0.9893 6 5 . 6 0.9839 63.7 0.9788 6 1 . 8 0.9736 5 9 . 8 0.9686 5 5 . 8 0.9588 52.0 0.9496 47.4 0.9389 42.9 0.9290 34.5 0.9118 26.8 0.8979 20.0 0.8874 8 8 . 9 1.0000 87.2 0.9956 85.4 0.9912 83.6 0.9869 81.8 0.9825 8 0 . 1 0.9786 78.2 0.9742 74.6 0.9665 71.2 0.9592 67.0 0.9506 6 3 . 0 0.9427 5 5 . 3 0,9292 4 8 . 4 0.9184 42.1 0.9110 106.7 1.0000 105.2 0.9964 103.6 0.0929 101.9 0.9893 100.2 0.9859 9 8 . 8 0.9827 9 7 . 0 0.9792 9 3 . 8 0.9729 9 0 . 7 0.9673 8 6 . 9 0.9605 8 3 . 2 0.9544 7 6 . 3 0.9444 69.9 0.9370 6 4 . 3 0.9323

In t h e ratio f/nP, composition is expressed a8

IKDUSTRIAL AND ENGINEERING CHEMISTRY

1270

TABLE v.

PARTI.4L

THERMODYKAMIC PROPERTIESa

c

Temp.,

F.

Pressure, Lb./Sq. In.

D. P. 0

70

100 200 300 400 500 600 800 1000 1250 1500 2000 2500 3000

D. P.

100

0 100 200 300 400 500 600 800 1000 1250 1500 2000 2500 3000

---o'sO~-

2

H2

0.1800 0.1804 0,1964 0.1878

h/mP 0.6005 1.0000 0.8221 0,6747

....

....

--2 -

0 1500 0.1704 0.1792 0.1751 0.1633 0.1548

0.70HI

O F %BUTANE I S THE

--

..

0 4449 1 0000 0.8352 0,6961 0.5855 0.4967

..

..

.. .. .. .. .. -14.1 15.7 9.2 2.9 -3.2 -9.2

..

0.4418 1.0000 0.8430 0.7075 0.5958 0,5054

..

..

.. .. ..

.. ....

..

..

....

0.1387 0.1346 0.1305 0,1233 0.1222 0.1185 0.1150 0 1089 0.1036 0,0968 0,0895 0.0753 0,0606 0.0473

....

....

i:9 0.2 -3.6 -7.6 -11.5 -15.5 -19.5 -27.1 -34.3 -42.2 -48.8 -59.3 -67.8 -77.0

1,0000 0.8694 0.7588 0.6656 0.5874 0,5194 0.4609 0,3666 0.2950 0.2283 0.1798 0.1180 0.8333 0.6327

....

....

0,1200 0.1192 0.1183 0.1171 0.1158 0,1144 0.1127 0.1088 0,1044 0,0985 0.0924 0.0787 0.0644 0.0504

....

HI

fZ/nzP

3:9 0.9 -2.2 -5.4 -8.6 -11.7 -14.6 -19.4 -22.9 -25.8 -27.6 -29.7 -33.8 -42.7

1.0000 0 8848 0.7836 0.6947 0.6166 0.5480 0.4879 0.3890 0.3126 0.2411 0.1888 0.1217 0.0845 0.0630

....

....

.... 0 1466 0.1408 0.1352 0.1297 0.1244 0.1195 0.1147 0.1059 0.0985 0 0894 0,0809 0.0665 0.0532 0.0416

15:7 11.4 6 8 2.2 -2.6 -7.4 -12.2 -21.9 -31.5 -42 8 -53.4 -71.7 -85.9 -96.0

1.0000 0.870i 0.7613 0.6697 0,5922 0.5263 0.4756 0,3796 0.3115 0 2481 0,2019 0.1415 0,1059 0.0842

0.1366 0.1313 0.1272 0.1231 0.1192 0.1158 0.1126 0.1065 0,1006 0.0933 0.0867 0,0709 0.0574 0.0440

1517 12.3 8.7 5.0 1.2 -2.6 -6.5 -14.4 -22.2 -31.5 -40.3 -55.9 -69.2 -80.1

1.0000 0.8788 0.7754 0.6870 0.6109 0.5452 0.4881 0,3948 0.3231 0.2554 0.2056 0.1408 0.1032 0.0808

0.1288 0,1266 0.1242 0,1218 0.1193 0.1167 0.1141 0,1089 0.1035 0.0974 0.0915 0,0784 0.0625 0.0464

1517 12.9 10.0 7.0 3.9 0.8 -2.4 -8.7 -14.8 -21.9 -28.5 -40.5 -51.3 -61.7

1.0000 0.8836 0.7825 0.6947 0.6182 0.5514 0.4931 0,3973 0.3235 0.2537 0.2018 0.1335 0.0949 0.0729

1,0000 0.8736 0.7691 0.6818 0.6083 0.5459 0.4926 0.4072 0.3427 0.2824 0,2374 0.1765 0.1388 0.1146

0.1430 0.1352 0.1283 0.1223 0.1170 0,1121 0.1075 0.0989 0,0909 0.0815 0.0730 0.0593 0.0484 0.0392

27.9 24.0 20.0 16.8 12.5 8.1 3.6 -5.6 -14.9 -26.3 -37.3 -56.7 -72.0 -82.8

1.0000 0,8801 0.7870 0.7014 0,6283 0.5656 0 5114 0.4231 0.3553 0.2915 0.2441 0,1804 0.1409 0.1153

0.1362 0.1315 0.1272 0.1228 0.1184 0.1140 0.1100 0.1017 0.0944 0.0868 0.0781 0 0647 0.0525 0,0408

27.9 24.7 21.4 18.0 14.4 10.6 6.8 -1.1 -9.2 -19.2 -29.0 -47.0 -62.0 -73.2

1.0000 0.8840 0,7851 0.6998 0.6264 0.5662 0.5079 0.4182 0.3179 0.2833 0.2346 0.1691 0,1293 0.1043

0.1324 0,1292 0.1259 0,1228 0,1196 0.1166 0.1136 0.1077 0.1020 0,0949 0.0880 0.0743 0.0589 0.0430

27.9 25.4 22.7 19.8 16.8 13.6 10.3 3.3 -4.0 -13.5 -23.0 -40.7 -55.5 -66.7

1.0000 0.8868 0.7887 0.7036 0.6294 0.5647 0,5081 0.4146 0.3419 0.2727 0.2210 0.1521 0.1119 0.0886

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1396 1344 1292 1218 1146 1074 1006 0896 0806 0716 0643 0536 0452 0368

40.4 37.1 33,6 29 9 26.1 22.1 18 1 9 6 1.0 -9.7 -20.0 -38.2 -52 4 -62.7

1.0000 0.8871 0.7907 0.7087 0.6391 0.5799 0 5295 0.4485 0.3868 0.3274 0.2823 0.2183 0.1757 0.1468

0 0 0 0 0 0 0 0 0 0 0 0 0 0

1356 1314 1266 1212 1152 1088 1026 0924 0862 0776 0708 0588 0483 0380

40.4 37.6 34.6 31 5 28.1 24.6 20.9 13.2 5.2 -4.9 -15.0 -33.7 -48.9 -59.6

1.0000 0.8898 0,7947 0.7130 0.6430 0.5830 0.5315 0 4484 0,3907 0.3215 0.2733 0.2060 0.1630 0.1350

0,1328 0.1289 0,1251 0.1208 0.1164 0.1118 0,1074 0.0993 0.0928 0.0864 0.0807 0.0689 0.0552 0.0404

40.4 38.1 35.7 33.0 30.0 26.9 23.5 16.0 7.7 -3.3 -14.6 -35.9 -51.6 -62.5

1.0000 0.8920 0.7982 0.7168 0.6460 0.5846 0.5312 0.4434 0.3749 0.3055 0.2545 0,1834 0,1397 0.1133

1338 1287 1228 1162 1094 1027 0961 0844 0744 0651 0582 0484 0406 0344

53.3 50.5 47.5 44.3 41.0 37.5 33.8 26.2 18.2 8.2 -1.4 -18 5 -31 6 -40.8

1.0000 0.8962 0.8069 0.7303 0.6647 0.6085 0,5601 0.4820 0.4223 0 3653 0.3214 0.2579 0.2144 0.1836

0 0 0 0 0 0 0 0 0 0 0 0 0 0

1316 1270 1220 1165 1108 1051 0994 0890 0797 0704 0633 0526 0437 0356

53.3 50.8 48.1 45.2 42.1 38.7 35.2 27.8 20.0 9.9 0.0 -18.3 -32.9 -43.2

1.0000 0.8978 0.8091 0.7324 0 6661 0.6088 0.5590 0.4777 0.4151 0.3551 0.3089 0.2428 0.2004 0,1684

0.1303 0.1261 0.1216 0.1168 0.1120 0.1070 0.1023 0.0934 0.0858 0.0784 0.0716 0.0592 0.0484 0.0389

53.3 51.3 49.0 46.5 43.7 40.6 37.3 29.8 21.2 9.4 -2.7 -25.3 -41.5 -52.4

1.oooo 0.8986 0.8104 0.7337 0.6669 0.6087 0.5578 0.4740 0.4082 0.3440 0.2942 0.2241 0,1791 0.1493

0 0 0 0 0 0 0 0 0 0 0 0 0 0

1275 1235 1183 1122 1051 0978 0906 0778 0676 0588 0524 0428 0368 0324 1219 1165 1110 1054 0995 0934 0868 0737 0622 0524 0466 0384 0335 0307

66.6 64 1 61.4 58.6 55.5 52.3 48 9 41 9 34.5 25.2 16 1 -0.2 -12.8 -21.8

1 .oooo 0.9047 0.8215 0.7493 0 6873 0.6339 0,5880 0.5143 0.4584 0.4041 0.3619 0.2996 0.2560 0.2231

0 0 0 0 0 0 0 0 0 0 0 0 0 0

1262 1225 1178 1125 1066 1002 0940 0820 0720 0633 0570 0476 0400 0332

66.6 64.4 61.9 59.2 56.3 53.2 49.9 42.8 35.3 25.6 15.9 -1.8 -15.8 -26.2

1.0000 0 .go54 0 8226 0.7503 0,6876 0 6331 0.5860 0.5094 0.4507 0.3940 0.3496 0,2840 0.2386 0.2062

0.1252 0.1228 0.1195 0.1158 0.1111 0.1057 0,0998 0.0882 0.0784 0.0700 0.0638 0.0545 0.0468 0.0354

66.6 64.7 62.6 60.2 57.4 54.4 51.1 43.6 35.1 23.2 10.8 -11.5 -27.2 -37.4

1.0000 0.9058 0.8224 0.7487 0.6839 0.6272 0.5778 0.4974 0.4356 0.3756 0.3289 0.2602 0.2122 0.1799

80.3 0.1223 8 0 . 3 1.0000 0.1225 78.5 7 8 . 2 0 . 9 1 2 3 0.1196 0.1178 76.6 7 5 . 9 0 . 8 3 6 1 0.1160 0.1130 74.3 0.1079 7 3 . 4 0.7676 0 . 1 1 3 8 71.7 0.1024 7 0 . 6 0.7084 0.1070 68.9 0.0966 6 7 . 6 0.6566 0.1013 65.7 0,0901 6 4 . 5 0.6114 0.0945 58.4 5 7 . 7 0 . 5 3 8 0 0.0818 0.0772 50.2 0.0660 5 0 . 4 0 , 4 8 3 5 0.0714 39.2 41 .O 0.4297 0 . 0 6 2 8 0.0562 27.8 0.0500 3 1 . 6 0.3884 0.0572 6.9 0,0436 1 4 . 4 0.3254 0.0500 -8.4 0 0368 0 . 9 0 , 2 7 9 3 0.0428 0.2457 0.0332 - 1 8 . 2 -7.7 0.0307 enthalpy, B. t . u. per pound. I n the ratio f / n P , composition is expressed

1.0000 0.9117 0.8464 0.7638 0.7025 0.6489 0.6021 0.5263 0.4684 0.4123 0.3677 0.3000 0.2510 0.2171

1.0000 0.8660 0.7538 0.6600 0.5816 0.5160 0.4617 0.3749 0.3109 0.2823 0.2092 0.1520 0.1182 0,0982

0.1315 0.1428 0,1348 0.1274 0,1208 0.1148 0 1089 0 0985 0,0893 0.0798 0.0716 0.0578 0.0468 0.0368

27.9 23.1 18.2 13.0 7.8 2 5 -2.7 -12.9 -22.6 -33.7 -43.9 -60.7 -72.5 -79.4

160

0 100 200 300 400 500 600 800 1000 1250 1500 2000 2500 3000

0.1608 0.1480 0.1409 0.1328 0.1250 0.1177 0.1113 0.0998 0.0903 0.0808 0.0728 0.0604 0.0463 0.0347

40.4 34.3 28.2 22 0 15.9 9.8 3.9 -7.5 -18.0 -29.6 -39.5 -54.6 -63.9 -68.0

1.0000 0.8718 0.7729 0.6857 0.6127 0.5610 0.4985 0.4147 0.3612 0.2914 0.2465 0.1846 0.1459 0.1200

0.1449 0.1400 0,1343 0.1275 0,1200 0.1122 0.1047 0.0920 0.0814 0.0716 0.0644 0.0530 0,0436 0.0356

40.4 36.2 31.8 27.4 22.9 18.4 13.9 4.8 -4.0 -14.5 -24.1 -40.4 -52.6 -60.8

0.7829 0 6981 0.6266 0.5660 0.5148 0.4336 0.3726 0.3164 0.2719 0,2088 0.1692 0.1423

0 100 200 300 400 500 600 800 1000 1250 1500 2000 2500 3000

0.1398 0.1350 0.1293 0.1230 0.1162 0.1092 0.1024 0.0906 0.0815 0.0730 0.0664 0.0554 0.0452 0.0342

53.3 47.5 41.5 35.6 29.7 23.8 18.0 6.8 -3.8 -15.9 -26.7 -43.7 -55.0 -61.3

1.0000 0.8712 0.7984 0.7186 0.6503 0.5920 0.5420 0.4616 0.3999 0,3406 0.2945 0.2296 0.1861 0.1576

0 0 0 0 0 0 0 0 0 0 0 0 0 0

1368 1316 1293 1186 1112 1040 0974 0855 0756 0660 0588 0480 0402 0340

53.3 49.5 45.6 41.6 37.6 33.4 29.3 20.9 12.7 2.7 -6.6 -22.7 -34.9 -43.2

1.0000 0.8941 0.8031 0.7254 0.6591 0.6025 0,5540 0.4757 0.4168 0,3591 0 3153 0.2528 0.2105 0.1803

0 1288 0.1242

66.6 63.2 59.6 55.8 52.0 48.1 44.1 36.1 28 1 18.4 9 2 -6.8 -19.0 -27.4

1.0000 0.9041 0 8210 0 7485 0.6865 0,6334 0.5878 0.5146 0 4588 0.4048 0.3625 0.3003 0 2566 0 2236 1 0000 0.9131 0.8376 0.7716 0.7141 0.6642 0.6208 0.5505 0.4974 0.4465 0.3986 0.3458 0.3017 0.2670

-

1.0000 0.8534 0.7312 0.6309 0.5494 0.4821 0.3951 0.3354 0.2689 0.2082 0.1648 0.1104 0.0796 0.0616

....

....

27.9 21.6 15.3 9.0 2.9 -3.2 -9.1 -20.2 -30.3 -41.2 -50.1 -62.5 -68.9 -69.8

1.0000 0,9031 0.8193 0,7467 0.6840 0.6199 0.5830 0,5068 0.4480 0.3908 0.3456 0.2782 0.2303 0.1979

....

1.00-

1.0000 0 8520 0.7268 0.6266 0,5454 0.4790 0.4240 0.3393 0,2778 0.2218 0.1815 0,1296 0.0987 0.0804

0.1590 0.1538 0.1579 0.1412 0.1340 0.1266 0.1197 0.1072 0.0964 0.0878 0.0776 0.0617 0.0466 0,0336

0 0.1304 66.6 0.1252 61.2 100 0.1194 55.7 200 0.1132 50.2 300 0.1066 44.6 400 0.1002 39 . O 500 0.0937 600 33.5 22.6 0 0821 800 12.1 0.0729 1000 0.0648 -0.2 1250 0.0586 - 1 1 . 4 1500 0.0512 - 2 9 . 6 2000 0 0430 - 4 2 . 3 2500 0.0332 - 5 0 . 3 3000 0 0.1220 80.3 250 75.4 0.1165 100 70.5 200 0.1110 65.5 300 0.1054 60.4 400 0.0994 55.4 500 0,0933 50.3 600 0.0868 40.3 0.0743 800 0.0644 1000 30.6 0.0562 1250 18.9 0.0511 1500 8.0 2000 0.0437 -10.3 0.0372 - 2 3 . 8 2500 0.0315 - 3 2 . 6 3000 a residual partial specific volume. fraction n-butane.

0.1560 3'9 -0.9 0.1535 0.1480 -5.8 0 1398 - 1 0 . 7 0.1310 -15 7 0.1249 -20.7 0.1201 - 2 5 . 7 0.1119 - 3 5 . 5 0.1044 - 4 4 . 9 0.0956 - 5 5 . 7 0.0870 - 6 5 . 4 0.0713 - 8 1 . 2 0.0570 - 9 2 . 7 0.0435 - 1 0 1 . 0

....

5

7 -

f,/n,P

1517 10.4 4.9 -0.8 -6.6 -12.4 -18.3 -29.7 -40.5 -53.0 -64.1 -81.8 -92.8 -97.3

0 100 200 300 400 500 GOO 800 1000 1250 1500 2000 2500 3000

220

....

0.90H2

SYSTEX

0.1614 0.1670 0.1588 0.1481 0.1386 0 .i?OO 0,1221 0.1085 0.0982 0.0880 0.0784 0,0625 0.0492 0.0366

130

190

2

N

-25.0 3.9 -2 0 -8.0 -14 1 -20.4

O F THE METHLUE-n-BUT.INE

Weight Fraction hlethane as Follows: 0.807 JdmP 1'2 H? fZ/nsP

..

0,1588 0.1689 0.1805 0.1801 0.1740 0.1660

GAS PHASE

VOL. 32, NO. 9

0 1184

ssis

0.

0 1120 0 1047 0 0972 0.0900 0 0772 0 0672 0 0588 0 0524 0 0428 0 0368 0 0324 1.0000 0 1218 80.3 77.1 0.9132 0 1160 73.8 0.8374 0 1103 70.3 0.7714 0 1043 66.7 0.7136 0 0982 63.1 0 . 6 6 3 3 0 0920 59.3 0.6195 0 0852 51.7 0.5481 0.0722 44.0 0 , 4 9 3 2 0.0613 34.6 0.4398 0 0524 25.6 0,3970 0 0460 0.3300 0 0384 9.7 -2.6 0.2799 0 0335 0 . 2 4 4 1 0 0307 -10 8 cubic foot per pound: E = partial

0 0 0 0 0 0 0 0 0 0 0 0 0 0

80.3 78.0 75.6 72.9 70.1 67.1 64.0 57.5 50.6 41.9 33.3 17.8 5.6 -2.8

1.0000 0.9130 0.8370 0.7706 0.7126 0.6620 0.6180 0.5469 0.4933 0.4424 0.4029 0.3435 0.2997 0.2653

as mole

SEPTEMBER, 1940


This relation is especially useful in cases where the components do not deviate greatly from the laws of ideal solution and the behavior attributed to perfect gases. The quantity fk/nJ' for methane and for nbutane has been recorded as a function of pressure and temperature in Tables IV and VI and in V and VII. I n general, it is believed that these quantities do not involve uncertainties greater than 0.5 per cent except a t states in the vicinity of the twophase region where the uncertainty is larger. I n each instance where the data extend to the two-phase boundary the value of f,/n,P has been tabulated for dew point. I t should be realized that although the fugacities of a component in coexisting phases a t equilibrium are equal, the values of the abovementioned ratio are not. It was not considered worth while to evaluate the fugacity throughout the liquid region since this may be accomplished readily from the partial specific volumes recorded in Tables VI11 and IX. The operation may be carried out a t any constant temperature and composition in accordance with the following expression :

FIGURE 10. EFFECT OF

COMPOSITION UPON THE RESIDU.4L PARTIAL SPECIFIC VOLUME O F n-BvTaxE I N THE GASPHASE AT 160" F.

tion of methane. This type of behavior was encountered in the liquid region throughout the temperature range of this investigation. I n order t o illustrate the general behavior of partial quantities in this system, the partial volume of methane is shown in Figure 13 as a function of composition in the single-phase regions a t 160" F. The data for the lower pressures were omitted in order to permit representation of the behavior in the liquid region on a suitable scale.

1271

0.0 3

2

Fugacity

E

I n the gaseous region the fugacity of a component (8) may be evaluated conveniently by the solution of the following equation (12) :

0.02

n

c: L

5 0.01

I>N

BUBBLE. POINT

0.00

-0.01 L

I 0.10

I

1

0.20

0.30

WEIGHT FRACTION

\

I

METHANE

FIGURE12. PARTIAL SPECIFIC VOLUMEOF nBUTANE IN THE LIQUID PHASEAT 160" F.

W a

0.15

5 I>*

It is often convenient to compare the behavior of a component in a phase with its behavior in an ideal solution (6). Under these circumstances the concept of the activity coefficient (9)is useful. This quantity may be defined for a component of a phase by the following expression (9):

0.10

~~

0.10

0.20

0.30

WEIGHT FRACTION METHANE

FIGURE11. PARTIAL SPECIFICVOLUME OF METHANEIN THE LIQUID PHASEAT 160" F.

The activity coefficient for methane is presented as a function of composition at 160" F. for several pressures in Figure 14. The fugacity, fiO, of methane in the pure state which was


1272

TABLE VI. Temp.

F,

70

Pressure,

0 100

D: 'P. 0 100 200

130

D: P. 0 100 200 300 400 500

160

D: 'P. 0 100 200 300 400 500 600 800 1000 1250 1500 2000 2500 3000

190

D: 'P

0 100 200 300 400 500 600 800 1000 1250 1500 2000 2500 3000

220

D: P. 0 100 200 300 400 500 600 800 1000 1250 1500 2000 2500 3000

250

D: P.

0

100 200 300 400 500

GOO

-

02, b

-0.00-

-

Vi

Lb./Sq. In

D: P.

100

PARTIAL VOLUMETRIC PROPERTIES" O F M E T H A N E I N THE

800 1000 1260 1500 2000 2500 3000

N

fi/niP

-0.10VI N

GASPHASE

VOL. 32, NO. 9

O F THE METHmE-n-BUTANE

SYSTEM

Weiaht Fraction Methane as Follows:

fi/niP

4 . 2 0 Vi fi/niP N

-

---

0 30fi/niP

VI

N

-0.40-

Vi

N

fi/niP

(31.3)b -0.015 1.0001 0.019 1.0000

(44.5) -0,014 0,9999 0.020 1.0000

(62.1) -0,013 0.9996 0.021 1.0000

(85.2) -0.012 0.9984 0.023 1.0000

(118.9) (171.0) -0.008 0,9979 -0.001 0.9939 0.025 1.0000 0.028 1,0000 0.004 0.9974 -0.010 0,9949

(51.6) -0.020 1.0003 0.019 1.0000

(74.0) -0.017 1.0000 0.020 1.0000

(103.4) -0,014 0,9940 0.021 1.0000 -U.O14 0,9992

(143.5) -0.011 0.9984 0.022 1.0000 -0.003 0.9977

(204.0) -0.006 0.9962 0.024 1.0000 0.006 0.9961 -0.005 0.9961

(300.2) 0.001 0.9911 0.027 1.0000 0.014 0,9947 0.007 0.9921

(165.2) -0.020 1.0018 0.021 1.0000 -0.009 1.0007

(233.8) -0.012 0,9981 0.022 1.0000 0.005 0.9967 -0.008 0.9974

(340.7) -0.002 0.9927 0.024 1.0000 0.013 0.9954 0.005 0.9933 -0.001 0.9929

(536.0) 0.009 0.9794 0.025 1.0000 0.020 0.9948 0.016 0.9898 0.013 0.9860 0.011 0.9829 0.010 0.9798

....

... ...

(80. 8 ) -0.029 1.0035 0.018 1.0000

... ... ... ... ...

.... .... .... .... ....

(121.O) -0.046 1.0024 0.017 1.0000 -0.024 0.9998

... ... ...

... ... ... ... ... ... .. .. .. ...

....

.... .... ....

.. .. .. .. .... .

I

.

.

.... ..... ...

....

(174.4) -0,075 1.0056 0.012 1.0000 -0,007 0,9988

... ...

.... .. .... .. ... ... ... ... ... ...

.... ..... ... .... .... .... .... ....

.... .... .... ....

(243.5) -0.126 1.0107 0.004 1.0000 0.012 0.9972 -0,073 1.0016

...

... ... ... ... ... .... .. ... ... ...

....

.... .... .... .... .... .... .... ....

.... ....

(330.4) -0,182 1.0160 0.008 1 . 0000 0.035 0.9946 0.012 0.9901 -0,144 0.9937

-

... ... ... ... ... ... ... ... ... ...

.... .... .... .... .... ....

.... ....

.... ....

...

....

...

(116.5) -0.027 1.0027 0.019 1.0000 -0.023 0.9983

...

.... ....

....

... .... .. .... .. ... ... ... ...

.... .... ..... ... ....

.... ..

.... ....

... ...

....

.... ....

... ...

...

... .... .. ... ...

...

.... .... ....

... ... ... ... ... .... ..

... ... ...

... ...

.... ....

... ... .... ..

.... .... .... ....

...

residual partial volume, cubic foot per pound.

....

... ...

....

....

....

.... .... ....

.. .. .. .. .... .... .... .... .... .... ....

... ... ...

....

*..

... ... ... ... ... ...

(590) -0.129 1.0680 0.013 1.0000 0.014 0.9965 -0,021 0.9969 -0.058 1.0059 -0.083 1.0217 -0.107 1.0433

.... .... .... .... .... ....

.... ....

... ...

....

- 0 . 19(!21)1 ,0786 -0.002 1.0000 0.022 0.9966 -0,012 0.9977 -0.093 1.0058 -0,145 1.0315 -0,189 1.0686

.... .... .... .... ....

(389.5) -0.056 1.0178 0.017 1.0000 0.006 0.9971 -0.025 0.9993 -0,044 1.0073

.... ..... ... .... .... .... ....

.... .... .... .... .... .... .... .... ....

... ... ... .. .. .. ... ... ... ...

....

(371.8) -0,139 1.0386 0.010 1.0000 0.013 0.9968 -0.047 1.0000 -0.112 1.0182

...

.... ....

(259.0) -0.030 1.0037 0.020 1.0000 0.001 0.9975 -0.022 1,0001

....

(261.O) -0,069 1,0117 0.015 1,0000 0.000 0,9967 -0.054 1.0030

....

... ...

.... ....

(180.0) -0.039 1.0034 0.019 1.0000 -0.010 0.9988

.*.

....

...

...

... ... ...

...

: 0.010 0 004

-0.009 -0.048 -0.070 -0.086

-0.100 -0.116 -0.114 -0.085 -0.046 0.014 0.033 0.033

....

1 . 0000 0.9983 0.9973 1.0037 1.0162 1.0331 1.0537 1 ,0803 1.1108 1.1718 1.2111 1.2306 1.1997 1.1603

...

....

...

....

...

....

.... ....

... ...

(379.2) -0,021 1.0015 0.021 1.0000 0.009 0.9963 -0,004 0,9957 -0.015 0.9981

.... .... ....

... ..... *

... ... ... ... ...

.... .... .... .... .... .... ....

... ...

-o.04b612)1.0154 0.019 1.0000 0.012 0.9964 0.001 0.9948 -0.012 0.9962 -0.022 1.0002 -0.031 1.0062 -0.040 1.0143

... 0:0i5 0.015 0.004 -0,009 -0.021 -0,030 -0.038 -0.048 -0.048 -0.036 -0,019 -0.010 0.019 0.022

.... .... .... .... .... .... i:0060

0.9641 0.9941 0.9948 0.9981 1.0038 1.0114 1.0310 1.0536 1.0789 1.0953 1.0992 1.0789 1.0534

.., .... 0:0o9 1.0000 0.004 -0,003 -0.009 -0.015 -0,021 -0.026 -0.033 -0.036 -0.030 -0.017 -0.011 0.009 0.014

0.9987 0.9986 0.9998 1.0024 1.0061 1.0112 1,0238 1,0384 1.0570 1.0702 1.0773 1.0705 1.0567

... ...

.... ....

-o.01(1588)o.9920 0.022 1.0000 0.017 0.9952 0.011 0.9920 0.006 0.9899 -0.001 0.9893 -0.006 0,9901

... ... ... ... ...

... ... ...

0:ljio 0.018 0.015 0.011 0.007 0.003 0.000 -0.006 -0.009 -0.008 -0.003 0.008

0.017 0.019

0:0i7 0.017 0.015 0.013 0.010 0.008

0.006 0.001 -0.004 -0.006 -0.004 0.006 0.010 0.014

o:oi3 0.012 0,010 0.008

0.005 0.003 0,001 -0.004 -0.006 -0.005 -0.003 0.000 0.003 0.006

.... .... ....

..... ... .... ....

.... ....

1.0000 0.9956 0.9919 0,9889 0.9870 0.9858 0.9854 0.9868 0.9902 0.9950 0.9983 0.9952 0.9830 0.9667

....

1.0000 0.9962 0.9928 0.9898 0.9873 0.9854 0.9838 0.9824 0.9832 0.9857 0.9884 0.9876 0.9788 0.9658

....

1.0000 0.9974 0.9952 0.9933 0.9920 0.9911 0.9907 0.9915 0.9934 0.9963 0.9985 1.0001 0.9981 0.9930

... ....

0:023 0.022 0.020 0.018 0.016 0.014 0,011 0.006 0.003 0.003 0.007 0.011 0.016 0.016

1.0000 0.9995 0.9895 0.9849 0.9809 0.9773 0.9744 0.9680 0.9660 0.9643 0.9614 0.9509 0.9365 0.9201

... o:lji1 0.020 0,019 0.018 0.016 0.015 0.013 0.010 0.008

0.007 0.007 0.008

0.010 0.011

o:ois

0.018 0.017 0.016 0.015 0.014 0.013 0.011 0.009 0.007 0.006 0.005 0.006 0.008

0.9605 0.9547 0.9487 0.9414

.. o:Ois

0.015 0.014 0.013 0.012 0.011 0.010 0,009 0.007 0.007 0.005 0.004 0.003 0.003

I n the ratio f / n P , composition is expressed as a mole fraction of methane.

Figures in parentheses indicate dew-point pressures in pounds per square inch.

required in the evaluation of this quantity was obtained from published data (19). It is difficult to estimate with accuracy the fugacity of pure gaseous n-butane at pressures above its vapor pressure a t the temperature in question. For this reason the quantity

fi/noP was employed in Figure 15 instead of the activity coefficient to depict the fugacity of n-butane a t 160" F. This quantity is not markedly affected by composition except in the liquid region. The data used in locating the phase boundaries were taken from a recent publication (11)

SEPTEMBER, 1940 TABLE VII. Temp.,

' F.

io

100

130

Pressure,

D: P. 0 100

D: P. 0 100 200 D: 'P. 0 100 200 300

D: P. 0 100

zoo -.. 300 400 500 600 800 1000 1250 1300 2000 2300 3000

190

D.' P. 100 200

300

400 500 600

Ron 1000 12.50 I500 2000 2500 3000

220

D'.'P. 100 200

300 400

500 600 800 1000 1260 1500

2000 2500 3000 250

D: P . 0 100 200 300 400 500 600 800 1000 1250 1500 2000 2500

3000

-

a 7

2

VOLUMETRIC PROPERTIES5

PARTIAL

OF

n-BcT.0-E

--0.10~

4 . 0 0 -

I N THE

GASPHASE

O F THE

1273

METHANE+-BUTANE SYSTEM

K e i s h t Fraction RIethane as Follows: 20--0 30-

-a,

Lb./Sq. I n

400 500

160

IKDUSTRIAL AND ENGINEERING CHEMISTRY

, 4 0 7

--0

-

fdmP

T'?

(31.316 0.216 0.9369 0.189 1.0000

....

...

(51.6) 0.200 0.9101 0.177 1.0000

... ...

.... ....

(80.8) 0.185 0.8784 0.165 1.0000

...

....

... ... ...

....

....

...

....

....

(121.0) 0.170 0 8338 0.153 1.0000 0.165 0.8712

... ...

.... ....

...

.... .... .... .... .... .... .... .... ....

... ...

...

... .

.

I

... ... ...

...

....

(44.51

0 219 0.189

...

0.201

0.176

... ...

....

... ... ...

... ...

.. .. .. .. .... ....

... ... ...

.... ....

.. .. ..

.... .... .... .. .. .. ..

... ... ... ...

.... (218.5)

0.135 0,136 0.132 0.143

... ... ... ... ... ... ...

...

...

...

...

0.7S78 1.0000 0 8951 0.8070

.... .... .... ....

.... ....

.... .... .... ....

....

(330.4) 0,154 0,7256 0.127 1.0000 0.120 0.9107 0.128 0.8304 0.146 0,7492

... ... ... ... ... ... ... ...

...

.... ....

.... ....

...

.... ....

.... .... ....

... ... .... .. ... ... ... ......

.... .... .... .... .... ....

...

... ... ... ...

0.7208

i.onoo

0.8864 0.7808

.... .... .... ....

...

(371.8) 0.157 0.6561 0.13,; 1.0000 0.133 0.8991 0.140 0.5069 0.154 0.7174

....

...

.... .... .... .... ....

... ... ...

.. .. .. ... ... ... ...

0.161

...

....

... ... ... ... ....

....

.... .... .... .... ....

...

... . . ... ... ... ...

....

.... ....

...

....

....

...

....

...

(?,SO. 5 )

0 189

1.0000

....

...

....

...

(233.5) 0.175 0.6861 0.164 1,0000 0.173 0.8535 0,177 0.7249

... ...

.... ....

...

....

(379.2) 0,153 0.5929 0.153 1.0000 0.159 0,8725 0.161 0.7583 0.157 0.6598

...

.... .... .... .... ....

... ... ... ... .. .. .. ... ...

.... .... .... ....

....

...

(115.9) 0.211 0.7770 0.189 1.0000 0.214 0.8095 (204.0)

0.193 0.173 0.195 0.193

...

....

....

...

(5R8) 0.4628

0.141 0.153

I

.

0.151 0.154

0.6896

0.145 0.145

0.6992

0.136 0.134 0.131 0.128 0.121 0.113

I

.

.

... I

.

.

... .. .. ..

...

... ... ...

0.143 0.135

0,5169 1.0000 0.8957

0.136 0.143 0.146 0.143

0.8074 0,7220

0.6431 0.5724

.... .... .... .... ....

...

...

.... .... ....

...

. . . .... 1.0000

o:iii

0.123 0.123 0 125 0.134 0.138 0.139 0.136 0.126 0.106

0.085

0.047 0.030 0.018

0.9088 0.5275 0.7520 0.6805 0.6134 0.5520 0.4475 0.3660 0.2928 0.2448 0.1597 0.1632 0.1490

.... ....

.... .... .... ....

... ... ...

...

...

(590)

0.134

.... ....

o:i34

0.131 0.131 0.131 0.131 0.130 0.127

0.120 0.110 0.097 0.083 0.059 0.037 0.023

....

1.0000 0,9002

0.8112

0.7309 0.6584 0.5934 0.5357 0.4401 0.3664 0.2977 0.2489 0.1894 0.1589 0.1422

... o'.iig 0.121 0.121 0.121 0.120 0.118

0.116 0.110 0.101 0.087 0.074 0.065

0.040 0.025

....

1.00oo 0.9095 0.5292 0.7360

0.6897 0.6296 0.5756 0.4839 0.4118 0.3443 0.2953 0.2313 0.1943 0.1728

....

...

0.140

0.144

.... .... .... .... .... .... ....

.

0:

.. .. ..

0.3lti5

... ... ...

1.0000

...

0.5557

... ... ...

(812) 0.142 0.4812

0.6205 0.z500

0,7624 0.0608

0.151 0.146 0.142

0.8889 0.7888

.... .... .... .. .. .. .. .... .... .... .... ....

1.0000 0.8735

0.156 0.155

0.142 0.143 0.144

...

0.6856 1.0000 0.8345 0.6905

(340.7) 0.165 0.5898 0.163 1,0000 0,171 0.8568 0.170 0.7320 0.16G 0.6272

0.6139 i.0000 0.8865 0,7834

0.153 0.142 0.146

...

.... ....

1.0000 0.8715 0.7553

0.162

.... 0.8279 0.7477 0.6651 0.5943

.... .... ....

0.153

.... ....

0.9058

....

(259 0 ) 0.162 0.6943

... ... ... ...

(521) 0.5785 1.0000

0.130 0.122 0.125 0.142 0 151 0 154

0.8520

... ... ... ...

....

0.154

= residual partial volume, cubic f o o t per pound.

0.182

.... .... .... .... ....

.... .. ...

....

(165.2) 0.181 0.7637 0.164 1 0000

.... ....

... ...

0.8318

...

....

0.148 0.156

....

0 200'

.... .... .... (261 .IO)

... ... ... ... ...

(143.5) 0.198 0.7656 0.176 1.0000 0.8324 0.198

.... ....

... ... ...

...

(103.4) 0 200 0.8'766 0 176 1.0000

...

....

(180.O) 0.167 0.7751 0.153 1.0000 0.164 0.8709

.. .. ..

(S5.2) 0.215 0.8263

.... ....

0.159

...

....

( 1 16.6) 0.151 0.8279 0.165 1.0000 0.153 0.8513

0.142

1 0000

0.8730 1.0000

....

0.142

0.8578

....

(74.0)

(174.4) 0.160 0 8082 0.145

0.9120 1.0000

(62.1) 0.220 0.8780 0.189 1.0000

....

iiz

1.o w 0

0.8889 0.7915

0,135

0.7058

0.6307 0.5647 0.6068 0.4117 0.3331 0.2665 0.2153

0.101

0 089 0.064 0 013

0.1554 0.1268 0,1072

0.028

..

o:ik

0.125 0,125

0.122 0.120 0,117 0.114 0 . l0G

....

1.0000 0.9012 0.5147 0.7383 0,6703 0,6008 0.5662 0.4668

0.3964

0.097 0.087

0.3308

0.077 0,055 0,040 0,026

0.2806 0.2145 0.1768 0.1551

... 0 : ii5

0.121 0.117 0.113 0,109 0.108 0.100 0,092

0.083 0,074 0.067 0.055

0.041 0.025

....

1 .0000 0,9105 0.5316 0.7619 0,7002 0.6455 0.5969 0,5156 0.4512 0.3852 0.3393 0.2657 0.2238 0.1968

(171.0) 0.199 0.6990 0.186 1.0000 0.209 0.8129 (300.2) 0.183 0.5526 0.171 1.0000 0.189 0.8387 0.189 0.6979 (536.0) 0.4656

0.142

0.162 0 lti2

1.0000 0.5614 0.7428 0,6428 0.5555 0.4881

0,lGO 0,155 0 1.50 0 . 144

....

o:iSe

1.0000

0.15:i 0.149

0.8749

0.144 0.139

0.6731 0.6959 0.5287 0.4711 0.3787

0 . 7666

0.134 0 130 0 . 120 0.111

0.30'35 0.24AO 0.2001 0.1185

0 . 09!) 0.087 0 0G3 0 . 046

0.1140

0 0;io

0.0980

o:iii

1.0000 0.5901 0.7948 0.7123

....

0.135 0.134 0.120 0.12.L

0.6410

0.10:3 0.083

0.5795 0.5262 0.4393 0.3725

0.085

0.3057

0.077

0.2607 0.1955

0.118

0.llR

0.061 0.047

0.1565

0.0:32

0.1327

iiz

1.0000 0.9020 0.8165 0.7421

0:

....

0.127 0.122 0.117 0.112

0.6772 0.6205

0.107

0,102 0.091

0.5710 0.4896

0.083 0.075

0.4263

0.3643 0.3136

0.069 0.057

0.2455

0.044

0.2005 0.1724

0.031

.. 01 i24

0.118 0.113 0.107 0.102 0.096 0.091 0.050 0.071 0.064 0.059 0.051 0.041 0.031

....

1.0000. 0.9118 0.5349 0,7677

0 . 7059

0.6573 0.6120 0.5372 0,4786

0.4210 0,3746

0.3035 0.2544 0.2219

I n t h e ratio f / n P , composition is expressed as mole fraction of n-butane.

b Figures in parentheses indicate dew-point pressures in pounds per square inch.

relating to the phase behavior of the methane-n-butane system. The enthalpy of complex hydrocarbon systems is of value in many calculations of industrial interest. Information concerning the partial enthalpies of the components of such a

system yields the specific enthalpy of the phase by application of the following relation: k = n H = k = l

a k n k

(8)

1274


VOL. 32, NO. 9

I

1 0

ilf

1275

INDUSTRIAL AIVD ENGINEERING CHEMISTRY

SEPTEMBER, 1940

?DN . . . . . . . . *cCcLo c c=-= .. .. .. .. .. .. .. ,. ..0c=c 1 03

I

. .

,, ..

. . . ..

.. .. . ..

1276


tion for financial assistance. James V. Reynolds contributed materially to the experimental program, and Louise M. Reaney, L. Fay Prescott, and Bruce L. Hicks assisted with the extensive calculations associated with the preparation of these data. Donald A. Emberson prepared the tracings for the figures. The Southern California Gas Company through Guy Corfield made available the Buttonwillow natural gas used as a source of methane.

1.00

9 E

1.40

1.20

5

g 3 8

VOL. 32, NO. 9

1.00

Nomenclature

y 0.80 k

2

*

b

= specific gas

f

0.m

i

G

k

constant

= fugacity, lb./sq. in. = value of any extensive property of a sys-

tem of other than unit weight G = specific value (per pound) of any extensive property = partial specific value of any extensive a20 pro erty H = enthagy, B. t. u./lb. = partial enthalpy, B. t. u./lb. 010 0.20 0.~0 o m aso am 0.70 0.80 0.90 m = weight, lb. n = weight fraction WEIGHT FRACTION METHANE n = mole fraction P = pressure, lb./sq. in. abs. FIGURE 13. PARTIAL SPECIFICVOLUMEOF METHANEIN THE METHANET = thermodynamic temperature, ' R. (' F. %-BUTANE SYSTEM AT 160" F. 459.69) V = specific volume, cu. ft./lb. V = residual volume (bT/P - V ) , cu. ft./lb. .V = residual partial volume, cu. ft./lb. The partial isothermal enthalpy-pressure coefficients of each of the components may be obtained by the methods of Rooze( ~ 1 = activity coefficient boom (10) from the information concerning the isothermal Subscripts enthalpy-pressure coefficients containcd herein. From these the partial enthalpies of the components were established A = a standard state b = bubble point by evaluation of the integrals in the following expression, since k = any component in a system containing n components a t infinite attenuation is independent of composition: i = all components except k = methane = n-butane Superscript 0 = component in pure state

d

0.40

+

I

Hk

The heat capacity for methane a t infinite attenuation represented by CP,O in this equation was established as a function of temperature from the spectroscopic data of Vold (17); similar information for n-butane was obtained from published values (16)obtained by use of the adiabatic expansion method. The resulting values of the partial enthalpy for methane and n-butane are recorded as functions of pressure, temperature, and composition in Tables I V and V, respectively. These values were obtained only for mixtures containing more than 0.6 weight fraction of methane and are based upon a reference state of infinite attenuation a t 60" F. I n general it is believed that the partial enthalpies do not involve uncertainties greater than 3 per cent except in the vicinity of the two-phase region or at low weight fractions of the component in question where the uncertainty is larger. From the values of residual specific volume, partial enthalpy, and fugacity recorded in Tables IV and V for methane and n-butane, it is possible to compute a number of other thermodynamic quantities. For example, the detailed method for establishing the partial entropy from these data has been described (12).

1.06

I-

1.04

9 LL w LL

8 > 1.02

c, > -

I-

U

a

1.00

I

Acknowledgment This investigation was prosecuted as a part of the activities of Research Project No. 37 of the American Petroleum Institute to whom the authors wish to express their apprecia-

,

I

20 WEIGHT

40

60

FRACTION

M E THANE

80

FIGURE 14. ACTIVITY COEFFICIENT OF METHANE IN PHASE AT 160" F.

THE

GAS

SEPTEMBER, 1940

INDUSTRIAL AND ENGINEERIKG CHEMISTRY

1277

Literature Cited Budenholeer, Sage, and Lacey, IND. EFG. CHEM.,32,384 (1940). Deming and Shupe, Phys. Rev., 37, 638 (1931). Kay, IND. EKQ.CHEM.,30,459 (1938). Keyes and Burks, J . Am. Chem. Soc., 49, 1403 (1927). Kvalnes and Gaddy, Ibid., 53,394 (1931). Lewis, J. Am. Chem. SOC., 30, 668 (1908). Lewis, PTOC.Am. Acad. Arts Sci., 43, 273 (1907). Lewis and Randall, “Thermodynamics and Free Energy of Chemical Substances”, p. 205, New York, McGraw-Hill Book Co., 1923. Noyes and Bray, J. Am. Chem. SOC.,33,1693 (1911). Roozeboom, “Die heterogenen Gleichgewichte”, Vol. 11, part 1, p. 288 (1904). Sage. Hicks, and Lacey, IND. ENG.CHEM., 32, 1085 (1940). Sage and Lacey, Ibid., 31, 1497 (1939). Sage, Webster, and Lacey, Ibid., 28, 1046 (1936). Ibid.. 29, 658 (1937). Ibid., 29, 1188 (1937). Ibid., 29, 1309 (1937). Vold, J. Am. C h a . SOC.,57, 1192 (1935). WEIGHT

FIGURE 15. EFFECT OF

FRACTION METHANE

COMPOSITION UPON THE FUG.4CITY O F ?%-BUTANE I N

THE

GAS PHASEAT 160’ F.

Drying of Papaya Latex STABILITY OF PAPAIN Reasons for the relative inactivity and poor keeping quality of commercial papain have been sought. It has been found that the enzyme loses much of its activity on drying and shortly thereafter, and still more of i t on being diluted just prior to use. Methods for minimizing these losses are suggested. Papaya latex is shown to contain a thermostable factor that destroys enzyme activity, apparently through an oxidative process.

R

E C E N T experiments with purified (6) and with crystalline ( 2 ) papain have shown that the proteolytic activity of the enzyme itself, measured under optimum conditions, is of the same order of magnitude as the activity of the pancreas proteinases. Furthermore, there is reason to think that, of the total solids in fresh papaya latex, over half is enzyme protein so that fresh latex is an extremely active proteolytic agent. On the other hand, the activity observed generally for commercial preparations of papain is relatively so low that a heavy loss of enzyme must have occurred in preparing the latex for commercial use. The methods employed by industry for this purpose consist of drying the wet latex (which contains 80-85 per cent of water) in the air or in a vacuum oven. The dried latex is subsequently pow-

A. K. BALLS, H. LINEWEAVER, 4ND S. SCHWIMMER Food Research Division, Bureau of Agricultural Chemistry and Engineering, U. S. Department of Agriculture, Washington, D. C.

dered and sieved in some cases, and in this form appears on the market as papain. It is well known that oxidizing agents, including air, inactivate papain under suitable conditions. Some of the deterioration that occurs in commercial preparations is doubtless due to oxidation, although Frankel, Maimin, and Shapiro (4) showed that part of the enzyme in fresh latex exists in a form more labile than the rest. It may be that the decomposition of such a labile fraction during and directly after the drying process is responsible for large losses in activity. As evidenced by the following experiments, the deterioration of papain is rapid during and soon after drying. It is also faster in air than in vacuum, and particularly rapid in dilute solutions. Only part of the inactivated enzyme may be reactivated by cyanide.

Method of Assay The milk-clotting method of Balls and Hoover (1) was employed, except that the temperature was 30” instead of 40” C., and 5 instead of 10 cc. of “Klim” were used. Experience has shown that some samples of dried milk behave ir-

Phase Equilibria in Hydrocarbon Systems Methaneân-Butane System

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