Volumetric and Phase Behavior of Propene-Propane System

Volumetric and Phase Behavior of Propene-Propane System H. H. REAMER AND B. H. SAGE California Institute of Technology, Pasadena 4, Calif.

T h e processing of petroleum products involves the separation of propene and propane by fractionation, and a detailed knowledge of the phase behavior of the propenepropane system is useful. Compositions of the coexisting phases of this system were investigated at five temperatures between 10" and 190' F. Equilibrium ratios were established and the data were smoothed by use of the quotient of the actual equilibrium ratio and that predicted from Raoult's law. A t the lower pressures uncertainty in measurement of this variable limited the accuracy of the results, whereas at the higher temperatures the measurements of composition were the primary source of error. The molal volume of two

mixtures w-as determined at seven temperatures between 10' and 400" F. for pressures from 200 to 10,000 pounds per square inch. The data indicate for propane progressirely smaller deviations from Haoult's law as the temperature is decreased, but show a minimum deyiation for propene at approximately 100" F. The maximum deviation was for propane at 190" F. and at compositions near pure propene. Only small deviations from additive volumes were found throughout the entire range of pressures and temperatures investigated. The maximum deviation near the critical states of the system was 1.7% for a mole fraction propane of 0.6289 at 600 pounds per squnre inch and 220' F.

I

in resistance of a small movable platinum wire mounted parallel to the gas-liquid interface. The abrupt change in the resistance of this wire upon crossing the interface under conditions of fixed energy dissipation offered a fairly accurate means of determining the extent of the liquid and gas phases. The apparatus permitted withdrawal, through separate ports, of samples of both the liquid and gas phases under isothermal, isobaric conditions. The samples were stored in glass bulbs for analysis. The composition of the equilibrium phases was det,ermined in the manner described in connection lyith the study of the 1-butene*-butane system ( I O ) . The equipment employed for this analysis was based on the catalytic hydrogenation methods proposed by Illchlillan, Cole, and Ritchie ( 8 ) . Duplicate gas and liquid phase samples were withdrawn a t each experimentally studied state and for each of these samples the mole fract,ion of propene was established, thus yielding duplicate data for each phase. Appropriate corrections were made for the deviation of the propene, propane, and hydrogen mixtures from ideal solution and perfect gas behavior under the conditions encount,ered in the analytical equipment. The volumetric measurements were made in a somewhat different type of equipment, (11). This apparatus was similar in principle to a closed-end, U-tube manometer, the sample being confined in the closed limb and the position of the mercury column being measured in the other limb. The sample was agitated by electromagnetic drive. The quantity and composition of sample used in the volumetric measurement were established by a precision mighing bomb technique (11). In each type of equipment the temperature of the working cell n-as determined by a platinum resistance thermometer calibrated by comparison with a standard instrument which was calibrated a t the National Bureau of Standards. It is believed t h a t the temperatures reported are related to the international platinum scale within 0.03' F. The pressure was measured by piston-andcylinder balances, the designs of which already have been described (12, I S ) , and which were calibrated against the vapor pressure of carbon dioxide at the ice point. The value obtained by Bridgeman (3) was taken as the reference standard. The calibrations of both pressure instruments have changed less than 0.05% during the past decade.

NFORMATION concerning the phase behavior of mixtures of propene and propane is of interest in the design of equiprnent used in the course of refining operations. Published data concerning the phase behavior of this system are not available for any wide range of temperatures. The volumetric and phase behavior of propane has been studied in some detail ( 1 , 4,9 , I S ) and its critical state has been well established ( 2 ) . Propene has not been investigated to as great an extent. The work of Graves (15) a t pressures up to 1250 pounds per square inch and other studies (6) a t higher pressures present data for the largest ranges of pressure and temperature that are currently available. The critical temperature and pressure were measured by Seibert and Burrell ( 1 4 )and by Winkler and hlaass ( 1 6 ) with fair agreement. MATERIALS

The propane utilized in these studies was obtained from the Phillips Petroleum Co. and contained less than 0,001 weight fraction of impurities. This relatively pure stock was subjected to fractionation at a reflux ratio of approximately 40 to 1 in a glass column packed with glass rings. The middle 80% of the overhead was utilized in this study. The purified material showed less than 0.2 pound per square inch decrease in vapor pressure a t 100" F. as a result of a change in quality from 0.05 to 0.50. The propane was stored in small stainless steel containers, from which it 1% as transferred into the equilibrium equipment. The propene also was obtained from the Phillips Petroleum Co. and a special analysis of the stock employed indicated less than 0.005 weight fraction of impurities. This stock was subjected to two successive fractionations in the glass column mentioned above. I n the fist fractionation, the middle 80% of the overhead was used as the feed for the second step and the corresponding fraction from the second distillation mas used in the experimental study, At 100" F. the purified propene indicated less than 0.4 pound per square inch decrease in vapor pressure as a result of a change in quality from 0.005 to 0.5. This material was stored in stainless steel containers until required for the volumetric and phase equilibrium studies. The phase equilibrium studies were carried out in equipment arranged t o permit the measurement of the relative volume of the liquid phase (12). This apparatus consisted of a stainless steel chamber, the effective volume of which could be changed by the introduction or withdrawal of mercury. Equilibrium was attained by the use of a spiral agitator which was driven by an external rotating electromagnet. The elevation of the mercury-hydrocarbon interface was determined by a movable electric contact, whereas the elevation of the gas-liquid interface was established from the change

The precision of pressure measurement a t any one time was approximat,ely 0.05 pound per square inch. The over-all error in pressure measurement must be judged on the basis of the sum of the uncertainties. The probable absolute error may be as large as 0.2 pound per square inch. The latter probable error in pressure measurements was associated with the equipment used for the phase equilibrium studies ( 1 2 ) and is nearly twice that encountered in the volumetric measurements ( 1 1 ) . For this reason correlations of the phase equilibrium data based in so far as practical upon the relat,ive values of pressure have been em-

1628

July 1951

INDUSTRIAL AND ENGINEERING CHEMISTRY

ployed. At temperatures below 100" F. the probable error in pressure measurement nearly controls the over-all uncertainty in the results. A review of the details of t h e operations involved in the determination of the composition of t h e samples withdrawn indicates that a t least 90% of the measurements should yield results within 0.002 mole fraction of the true value. At a limited number of states differences as large as 0.005 may exist. The errors associated with sampling are perhaps a controlling influence upon the

TABLE I. COMPOSITIONS OF COEXISTING PHASES IN PROPENEPROPANE SYSTEM Pressure,

Lb"Sq' Inch Abs.

Experimental Liquid Gas

Average Liquid Gas

7

49.55 49.55

56.6

0.1821° 0.2185 0.1814 0.2150 0.2511 0.2053 0.2495 0.3787 0.4363 0.3748 0.4324 0.4136 0.4650 0.4137 0,4656 0.5542 0.6045 0.5572 0.6050 0.6414 0.6874 0,6547 0.7016 0.7921 0.8112 0.7928 0.7989 0.8469 0.8644 0.8468 0.8640

82.82 82.82 88.3 83.3 87.16 87.16 87.8 87.8 90.29 80.29 91.7 91.7 94.8 94.8

0.l7QZa 0.2094 0.1774 0.2278 0.2043 0.2482 0.2074 0,2447 0.3811 0 4275 0.3760 0.4256 0,4117 0,4615 0.4148 0.4612 0.5594 0.5986 0.5615 0,6037 0.6567 0.6865 0.6540 0.6878 0.8437 0.8719 0,8470 0.8651

197.31 197.31 206.09 206.09 213.26 213.26 221.05 221 . 0 5

0.1782= 0.2047 0.1807 0.2055 0.4140 0.3f70 0.4116 0.5520 0,5913 0.5601 0.5933 0.7914 0.8108 0,7893 0.8107

50.0

50.0 51.99 51.99 52.2 52.2 54.12 54.12 54.8 54.8

w X

56.32 56.32 56.5

I >B

FRACTION

PROPENE

Figure 1. Difference in Mole Fraction Propene in Coexisting Phases of Propene-Propane System

uncertainty of measurement of composition in the case of the gas phase a t pressures below 200 pounds per square inch. Under these conditions entrainment of small amounts of liquid from the wall close t o the sampling port may alter significantly the composition of the sample withdrawn from t h a t of the gas phase. The average deviation of the duplicate measurements made upon pairs of samples taken a t the same state was 0.0034 mole fraction. This agreement between duplicate samples appears satisfactory in view of the techniques employed. T h e accuracy of determining the relative compositions of the coexisbing phases is somewhat less than the above-mentioned figure because of the small difference between them. It is believed that a t least 90% of the measured values of the molal volume of the two mixtures of propene and propane investigated have uncertainties less than 0.2% a t the indicated values of pressure, temperature, and composition. EXPERIMENTAL RESULTS

I n Table I are recorded the experimental values of the compositions of the coexisting phases. Duplicate analyses of the gas and liquid phases have been included when available. It is not believed that any particular pairing of the compositions of the coexisting liquid and gas phases is significant. The average of the values from duplicate measurements has been used. Figure 1 portrays the difference between the mole fractions of propene in the coexisting phases. The points indicated were determined by direct experimental measurement. The difference in composition which would exist if the system followed Raoult's law is indicated for 10" and 190' F. by dashed lines. The information submitted in Figure 1 shows that the deviation of the experimental data from smooth curves at the lower temperatures is somewhat larger than at the higher temperatures. As a part of Table I are presented ratios of the actual equilibrium constant of a component to that predicted by Raoult's law, which were established from the following relationship:

K Y P Kf;:=x5?

(1)

The values of the vapor pressures of propane and propene utilized in the application of Equation 1 are recorded in Table

10" F. 0.1818 0.2168

R/KR Propene Propane T -

-

1.0198b 1.0080

0.2053 0.2503

1.0510

1,0014

0.3768 0.4344

1 0336

1.0020

0.4136 0.4653

1.0124

1.0107

0.5557 0.6048

1.0151

1 0218

0.6480 0.6945

1.0125

1.0099

0.7924 0.8050

0.9861

1.1227

0.8468 0,8642

0.9941

1,0637

400 F,--------

7

MOLE

1629

c

398.71 398.71 414.49 414.49 428.28 428.28 443.37 443.37

0.l75Za 0.1946 0.1786 0.1955 0.3755 0.3986 0.3743 0.3965 0.5570 0.5784 0.5587 0.5801 0.7896 0.8025 0.7906 0.8032

7

543.89 543.89 565.49 565.49 582.76 582.76 583.54C 583.64 603.55 603.55

0.1778= 0.1868 0.1765 0.1878 0.3738 0.3877 0.3764 0.3875 0.5514 0.5621 0.5527 0.5635 0.5615 0.5518 0,5761 0.5658 0.7912 0.7958 0.7878 0.7960

0,1783 0.2188

1.052lb 0 , 9 9 6 4

0.2058 0.2464

1.0324

1.0005

0.3786 0.4266

1.0171

1.0185

0,4132 0.4614

1.0147

1,0224

0.5604 0.6011

1.0026

1.0373

0.6854 0.6872

0,9954 1,0536

0.8454 0 8685

1 0082

100' F. 0.1794 0.2051

1.0204

. . ~ _ _ ~7 ___

0.9921b 1,0113

0.3770 0.4128

0.9928

0.5560 0.5923

0.9996

1,0364

0.7904 0.8108

0 9979

1.0560

160' F -. 0.1769 0,1950

1,0278

7

0.965Sb 10156

0.3749 0.3976

0.9516

1.0406

0.5578 0.5792

0.9768

1.0617

0.7901 0.8028

0.9896

1.0549

190' E'. 0.1772 0.1873

7

0.9258b 1.0233

0.3751 0.3876

0.9407

1.0556

0.5520 0.5628

0.9564

1.0835

0.5688 0.5580

0.9215

1 1406

0.7895 0.7959

0.9795

1.1148

a All compositions expressed in mole fraction propene. This ratio of actual equilibrium constant t o t h a t obtained from Raoult's law is defined b y Equation 1. 0 I n this instance combined samples a n d analytical error exceeded difference in composition between liquid a n d gas phase3.

TABLE 11. VAPORPRESSURE OF PROPENE AND PROPANE Propene, Lb./Sq. Inch Abs.

10 40 100 160 190

58.0 96.6 227.3 455.3 621.2

Propane Lb./Sq.' Inch Abs.

47.1 79.0 189.0 383.9 525.0


1630

Vol.. 43, KO. 7

TABLE111. EQ~JILIBRIUM C~ONSTAKTS SYSTEM Pressure, Composition Liquid Gas I

0 0 0 0 0 0 0 0 0

I" 2 3 4 5 6 7 8 9

.4bs.

-

48.56 49.90 51 16 52.31 53.36 54.33 55.26 56.16 57 08

0 10 0.2 0 3 0 4 0 5 0 6 0 7 0 8 O B

0.12334" 0 23844 0.34677 0.44982 0.54780 0.64296 0.73535 0.82536 0.91350

O.la 0 2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

0.11695a 0.22848 0.33540 0.43816 0.53735 0.63366 0.72765 0.81976 0.91044

193.21 197.98 202.49 206.87 210.98 214.84 218.42 221.65 224.67

0 la

0 11024n 0 21716 0.3'2121 0.42268 0 52225 0 62016 0 71659 0 81200 0 90630

391 00 399 61 408.12 416.16 423 84 431 16 437 99 444 51 450 73

0 2 0.3 0 4

Figure 2. Ratio of Equilibrium Constants for Propane

0 . 1269Z5 0.24458 0.35415 0.45700 0.55460 0.64842 0 73934 0 82800 0 91485

";h/Y.

0 5 0.6 0 7 0 8 0 9

~

11,-

PROPEKE-PROPANE

Equilibrium Ratios Propene Propane KIll KIKR Ka K,'KR 10" F'-

--

1 2695 1 2229 1 1805 1 1425 1 1092 1 0807 1 0562 1 0350 1 0163

1.0629 1 0521 1 0413 1 0304 1 0202 1 0123 1.0063 1 0021 1 0004

0,8701 0 9443 0 9226 0 . 9050 0,8908 0,8789 0.8689 0 8600 0.8515

1 03137~

1 0012 1 0035 1 0068 1 0111 1 0165 1 0225 1 0286 1 0352 1 0422

1 0278 1 0199 1 0128 I 0074 1 0038 1 0017 1 0003 1 0001

1.1655 1.1424 1.1180 1,0954 1.0747 1.0561 1.0395 1.0247 1 0116

I 0002 1 0004 1 0022 1 0051 1 0092 1.0138 1 0195 1 0264 1 0319

0.9941b 0,9950 0 9960 0 9969 0.9975 0 9982 0 9988 0 9992 0 9999

0.9812 0.9644 0 9494 0 9364 0.9253 0.9159 0 9078 0.9012 0.8956

0 R467h 0.9530 0 9598 0,9659 0.9724 0.9788 0.9848 0 9909 0.9968

0.9886 0,9786 0.9697 0 . 9622 0 . 955-5 0.9496 0 9447 0.9400 0,9370

1 00.10

1 0102

i 0172 1 0249

1 0329 1 0411 1.0491 1.0569 1 0646

1 010'1 0 9192" 0.9925 O.lQ 0 1067Sa 534 7 3 1.0678 0.9270 0.9867 1 027.5 546.72 1.0533 0.2 0.21066 0.9351 0.9823 1 0458 557.86 1.0418 0 3 0.31239 0 9435 0 9789 1.0593 568 12 1.0316 0.41264 0.4 0 9524 0.9763 1 0746 577.90 1.0237 0 5 0 51185 1.0896 0.9614 0.9742 1.0172 0,61032 587.17 0.6 0.9712 0.9715 1 1030 0.7 0.70854 596.06 1.0122 1 1161 0.9813 0.9688 0.8 0 80624 604.85 1.0078 0 9916 0.9648 1 1277 613.59 1 0039 0.9 0.90351 Compositions of coexisting phases expressed in mole fraction proiiene. This ratio of actual equilibrium constant to that obtained from Rnoult's law ie defined b y Equation I.

11. They were based upon rarlier studies of these compounds (5, Q ) , supplemented by limited vapor pressure measurements for both components at, temperatures belo!\- 100' F. Thra lat,ter were made in the course of the present investigation. Good agreement exists between the new vapor pressure measurements and those rpported earlier. Thc ratio K / K R is shown for propane and propene in Figures 2 and 3 , respect,ively. For a system such as this, in which the vapor pressure of the components is nearly t,he same, this ratio is highly sensitive to small variations in the relative compositions of the coexisting phases. In locating the smooth curves at the lower temperatures, an effort has been inade to follow the limitat,ions imposed by the Duhom equation (?). The ratio defined in Equat,ion 1 should follow this equation if the gas phase is a perfect gas and the phases are ideal solutions. However, a t the higher temperatures, corresponding t o larger pressures, the ratio would not he expected to be in complete agreement with this relation. The average deviation of all the experimental points shown in Figures 2 and 3 from the smooth curves is 0.69'% for propane and 0.547, for propene. These average quant,ities were evaluated by means of the following: 6 =

Figure 3.

Ratio of Equilibrium Constants for Propene

.

ZXk6

3x

(2)

T h e foreaoina exmession for the average deviation was emu-- u

July 1951


ployed in order t o give greater weight t o the data obtained for a component present a t a high mole fraction. This evaluation of the deviation from the smooth curve appears desirable, because the values of K / K Rbecome indeterminate at compositions corresponding to zero mole fraction of a component. It is difficult t o smooth the composition of the coexisting phases directly. Complex relationships of composition t o pressure which are not justified by the experimental data often result from this procedure. Difficulties of this nature are encountered even when there exists a marked difference in the volatility of the components. Direct smoothing of data is particularly ineffective in the present instance because of the existence of a probable error of 0.2 pound per square inch in the absolute values of pressure associated with the phase equilibrium measurements. The precision that was indicated in this measurement was 0.06 pound per square inch. The ratio K / K R affords a more convenient and accurate means of accomplishing the correlation of the measurements of the composition of the coexisting phases. There is not more than a 17% change in this ratio for either component over the range of temperatures and compositions involved. This small percentage variation in the ratio with state permits a relatively precise smoothing and interpolation of the data. The corresponding variation in pressure is approximately twelvefold and the compositions vary from pure propane t o pure propene. For this reason the authors have chosen the ratio K / K R as the primary variable t o establish the phase behavior of the system. This ratio may be employed with greater precision than, and facility nearly equal to, the commonly encountered equilibrium ratio Y k / X k for systems a t relatively low pressure made up of components of comparable volatility. Smoothed values of K / K Rare reported in Table I11 along with corresponding values of equilibrium ratios for evenly spaced compositions of the liquid phase. The composition of the liquid has been employed as one of the independent variables because the same range of valueg is encountered at all temperatures. Such a situation would not exist if pressure were utilized for this purpose. The corresponding values of the composition of the gas phase and the equilibrium pressure have been included. The uncertainties in pressure a t the lower temperatures result in a number of pairs of experimentally measured compositions of coexisting liquid and gas phases deviating from the smoothed values upon a pressure composition diagram by as much as 0.022 mole fraction, which is about ten times the probable error of the composition measurements. I n the opinion of the authors this discrepancy results from the relatively large probable error in the measurement of pressure and is not caused by uncertainty in the composition measurements. Random uncertainties in measurements of composition would have been apparent in large discrepancies of the experimental points from the smooth curves of Figure 1. Table IV presents the compressibility factor and the molal volume of the two mixtures of propene and propane which were investigated. These data were smoothed with respect to pressure and temperature. The compressibility of a mixture of propene and propane containing 0.2411 mole fraction propene is depicted in Figure 4. The distribution of experimental points was typical for this investigation and the average deviation of the experimental data from the smooth curves was less than 0.1%. Figure 5 shows the influence of pressure upon Figure 5 . the molal volume of the same mixture of pro-

1

1631

I

200

400 PRESSURE

I

I

600 800 LB. PER. SQ. IN.

Figure 4. Compressibility of Propene-Propane Mixture Containing 0.2411 Mole Fraction Propene

pene and propane. The variation in bubble point pressure with temperature is indicated, but the bubble point pressure was small enough to make it difficult t o represent its behavior in any detail in this diagram. From the information available concerning the volumetric behavior of propane (9) and of propene ( 5 ) , it is possible t o compare the volume of the two mixtures recorded in Table IV with

Molal Volume of Mixture of Propane and Propene Containing 0.2411 Mole Fraetion Propene

1632


the v ol u m e t r i c b e h a v i o r ascribed t o an ideal solution (6). A comparison a t 34 s t a t e s i n d i c a t e s a n ,average deviation from additive volume irrespective of sign of 0.28%. The deviation from additivity averaged with the sign of the difference taken into account was 0.14%. T h e m a x i m u m deviation from additivity occurred near the critical state and amounted to a positive 1.7y0a t a mole fraction propane of 0.6289 a t 600 pounds per square inch and 220" F. A positive deviation of 1.47, was found at a pressure of 600 pounds per square inch and 220" F. a t 0.2411 mole f r a c t i o n propane. The phase e q u i l i b r i u m data recorded in Table 111 were obtained from direct measurements of the compositions of the coexisting phases, carried out in different equipment ( 1 2 ) from that employed in the volumetric studies (11). It is therefore of interest, as an over-all check of the consistency of the data, to compare bubble point and dew point pressures obtained for the same states from the volumetric and phase equilibrium m e a s u r e m e n t s . F o r the total compositions of the system for which volumetric data were available, bubble point and dew point pressures, respectively, were c o m p u t e d from values of K / & by application of the following equations : Pb

(K/KR)mnmpkl f ( K I K R )(1 ~ - ~ I I I ) ~ (3) ; =

XI11

P d

=

TABLE

Iv.

Pressure, Lb./Sq. Inch Abs.

Because the ratio K I K R is a function of pressure, a trial solution of these equat,ions is necessary. However, the advantage of using this ratio in the equation is that its value changes relatively little with wide changes in pressure, t h u s m a r k e d 1 y

FACTOR AND

Compressihility Factor

Volume

Cu.

Ft.1

Lb. Mole

hfOLAL L'OLCME Compressibility Factor

O F PROPENE-PROPANE h.IIXTURES

Volume Cu. Ft.) Lb. Male

Compressihility Factor

Volume CU. Lb. hfole

mi

MOLEFRACTIOS PROPENE. 0,2411 F. (83.3) b-

100' F. (198 0 )

40'

Dew point

...

Bubble point

(50.6)

1,500 1,750 2,000 2,250 2,500 2,750 3,000 3,500 4,000 4,500 5,000 6,000 7,000 8,000 9,000 10,000

1.273

0,02089

1.329

0.62478 0.03094 0.03709 0.04938 0.07385 0.09820 0.1467 0.1946 0.2421 0 3011 0.3589 0.4167 0.4739 0 5310 0.5876 0,6434 0.6992 0.8092 0.9180 1.0254 1 1316 1.3413 1.5472 1.7520 1.9549 2.1542

1 329 1.327 1,326 1.324 1.320 1.317 1.311 1.304 1.298 1,292

0.3682 0.4279 0 4873 0 5460 0.6047 0.6631 0.7210 0.8354 0.9492 1,0613 1.1727 1 3917 1.6079 1.8210 2.0315 2.2426

1.272 1.272 1.270 1,269 1.268 1.265 1.263 1,258 1.253 1.248 1.242 1.237 1.232 1.228 1.223 1.219 1.215 1.211 1.203 1.196 1,189 1.182 1 169 1,158 1 147 1.188 1 130

Bubble point 0 14.696 20 40 60 80 100 125 150 200 300 400 600 800 1,000 1,250 1,500 1,750 2,000 2,250 2,500 2,750 3,000 3,500 4,000 4,500 5,000 6,000 7,000 8,000 9,000 10,000

0 6038 0 1062 1,0000 0 9898 0.9862 0 9723 0,9578 0.9437 0.9288 0,9095 0.8896 0.8473 0 7483 0 6078 0.1522 0.1975 0.2416 0.2957 0.3490 0.4014 0.4527 0,5033 0 5530 0 6026 0.6515 0.7477 0.8426 0.9363 1.0288 1,2090 1.3853 1.5675 1.7280 1.8964

1401 3)a (403 8)

9 984

7jo m

447.9 327.9 161.6 106.2 78.45 61.77 48.39 39.44 28.17 16.59 10.10 1.687 1.641 1.607 1,573 1.547 1.525 1.505 1.488 1.471 1.457 1.444 1.421 1.401 1.384 1.368 1.340 1.316 1.295 1.277 1.261 280° F.

0 14.696 20 40 60

1,0000 0.9938 0.9914 0.9843 0.9759 0.9678 0.9593 0.9492 0 9390 0.9182 0.8761 0.8308

0.7675

23.20 (199 8)

0 01272

_____-__160° F. Dew point

...

(84,3)

0 14.696 20 40 60 80 100 125 150 200 300 400 600 800 1,000 1,250

= (K/KR)IIIXIIIP~Ii/nIIl

(5)

COMPRESSIBILITY

Vol. 43, No. 7

m

536.8 393.5 195.34 129.11 96.03 76.16 60.28 49.69 40.04 23,18 16,49

:

1.283 1.277 1.271 1 266 1.260 1,255 1.250 1,240 1.231 1.222 1 214 1.199 1.185 1.174 1.165 1 155

1900 F. (549.0) 0.4652 5.902 (651.0) 0,1640 2.074 1 0000 m 0.9912 470.3 0,9877 344,3 0.9753 170.0 0.9628 111.9 0.9603 82.82 0.9378 65.39 0.9220 51.43 0.9056 42.09 0.8718 30.39 0,7960 18.50 0.7042 12,28 0.1710 1.988 0.2103 1,833 0.2519 1.757

...

...

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

...

... ...

... ...

... ... ...

... ...

...

... ...

... ...

340' F. I . 0000 m 0.9960 581.7 0.9943 426.7 0,9981 212.0 0.9822 140.49 0.9759 104.69 0.9700 83.25 0.9623 66.07 0.9546 54.62 0.9393 40.31 0.9080 25.97 0.8763 18,80

0.04927

1.479

0.9174 0.8965 0.8675 0.8373

68 88 33.79 41.68 33 63

1'470

0 07340 0.09732 0.1445 0,1909 0,2364 0.2925 0,3477 0.4028 0,4571 0.5108 0.5639 0.6166 0.6682 0.7712 0.8718 0.9723 1.0709 1 2646 1,4550 1 6426 1.8283 2 0118

1 461 1.447 1 433 1 420 1.406

1.392 1.382 1.373 1.364 1.355 1.347 1.338 1.324 1.309 1.298 1,286 1.266 1,249 1.233 1.220 1.208 220' F. -~ ~

1.0000 0 9922 0 9890 0 9782 0 9668 0 9558 0 9416 0 9305 0 9163 0 8881 0 8300 0 7610 0 5788 0 2636 0 2774 0.3206 0.3684 0.4164 0.4637 0.5106 0.5569 0.6029 0.6484 0.7380 0.8265 0.9139 0,9999 1.1669 1.3321 1.4932 1.6502 1.8043

m

492.5 360.7 178.4 117.5 87.15 68.90 54.30 44.56 32.39 20.18 13.88 7,036 2.403 2.023 1.871 1,791 1.736 1.691 1.655 1,625 1.599 1.576 1.538 1.507 1.481 1.459 1.419 1,388 1,361 1.337 1.316 400'

1.0000 0.9968 0.9955 0,9908 0.9859

F. m

625.8 459.2 228.53 151.60 113.16 90.07 71.62 59.44 43.95 2 8 53 20,87

(Continued o n p a g e 1633)


July 1951

TABLE IV.

Compressibility Factor

600 800

0.7323 0.6198 0.4995 0.4276 0.4335 0.4632 0.4993 0.5395 0.5798 0,6209 0.6604 0.7422 0.A242 0.9048 0.9842 1.1398 1.2921 1.4424 1.5891 1,7332

Volume Cu. Ft.) Lb. Mole


280' F. 1,000

1,250 1,500 1,750 2,000 2,250 2,500 2,750 3,000 3,500 4,aoo 4,500 5,000 6,000 7,000 8,000 9,000 10,000

Volume

Cu. Ft.)

Lb. Mole


340' F. 9.689 6.150 3.965 2.716 2,294 2,101 1.982 1.904 1.841 1,790 1.747 1.683 1.636 1.596 1.563 1.508 1.465 1.431 1.402 1.376

0,8092 0.7400 0.6722 0.6031 0,5633 0,5558 0.5685 0.5922 0,6216 0.6547 0,6890 0,7603 0.9323 0.9053

Volume Cu. Lb. Mole

Ft.1

400' F.

11.57 7.939 5.769 4.141 3.223 2.726 2.439 2.259 2.134 2.043 1.971 1.864 1.786 1.726 1.680 1.610 1,552 1.505 1.469 1.442

0 8572

13.18 9.345 7.063 5 279 4.187 3.490 3.033 2.734 2,524 2,365 2.247 2.081 1.966 1.881 1.814 1.715 1.641 1.586 1.542 1.505

0 8103 0 7656 0 7152 0.6807 0,6620 0,6574 0.6668 0.6838 0.7049 0,7307 0.7896 0.8523 0.9174 0,9829 1.1151 1,2454 1.3757 1.5042 1.6307

-

MOLEFRA~TION PROPENE, 0.6289 10' F. (54.1)"~a

Dew point Bubble point

0

14.696 20 40 60 80 100 125 150 200 300

400 600 800 1,000 1,250 1,500 1,750 2,000 2,250 2,500 2,750 3,000 3,500 4,000 4,500 5,000 6,000 7,000 8,000 9,000 10,000

Dew point Bubble point

0

14.696 20 40 60 80 100 125 150

200 300 400 600

800

40' F.

...

(54.4) 0.01346 1.236 1.0000 m

...

...

...

... i 236

0.61471 0.01960 0.02449 0.03060 0.03669 0.04887 0.07313 0.09783 0.1454 0.1931 0.2406 0.2993 0.3576 0.4156 0.4729 0.5295 0.5867 0,6430 0.6989 0.8097 0.9196 1,0277 1.1359 1.3489 1.5582 1.7631 1.9644 2.1631

1.0000

m

.. .. ... ...

...

... ... ...

8,805

0.4410

1.720

...

(91.4) 0,02199 1.290

0,02406 0.03005 0.03603 0.04798 0.07176 0.09539 0.142a 0,1888 0.2350 0.2922 0 3490 0.4049 0.4602 0.5152 0.5698 0 6242 0.6775 0.7843 0.8897 0.9940 1.0969 1.2996 1.4909 1.6969 1,8896 2.0828

(432.6) 0,1120 1.0000 0.9905 0.9867 0.9732 0.9593 0.9454 0.9313 0.9132 0.8946 0.8536 0.7586 0.6298 0.1496 0.1935

...

1.235 1.235 1.234 1.233 1.282 1.229 1.227 1.221 1.817 1.213 1.207 1.202 1.197 1,192 1.186 1.183 1.179 1.174 1.166 1.159 1.151 1,145 1.133 1.122 1.111 1.100 1.090

160' F. (430.5) 0.5718

(90.4)b

i :is0

1.289 1.288 1.287 1.283 1.279 1.271 1.266 1.260 1.254 1.248 1.241 1,234 1,228 1.222 1.217 1.211 1.202 1.193 1.185 1.176 1.162 1.149 1.137 1.126 1.117

190° F. (588.3)

looo F. (213.8) 0 7417 20 76 (215.5) 0.0517 1.440 1 .oooo m 0.9870 403.1 0.9818 294,9 0.9634 144.7 0.9445 94.55 0.9248 69.44 0.9050 54.36 0.8785 42.21 0.8497 34.03 0 7748 23.27 0.07153 1.432 0.09480 1.424 0.1407 1.408 0.1856 1.394 0.2300 1.382 0,2849 1.369 0.3392 1.358 0.3910 1.346 0.4446 1.335 0.4967 1.326 0I5479 1.316 0.5986 1.308 0.6490 1.299 0.7481 1.284 0.8459 1.270 0.9423 1.258 1.0381 1.247 1.2269 1.228 1.4115 1.211 1,5926 1.196 1.7685 1.180 1.9415 1.166

.

220° F.

5.221 (590.0) 0,1808 2.138

m

m

448.2 328.1 161.8 106.3 78.59 61.94 48.59 39.66 28.38 16.82 10.47 1.658 1.609

470.8 344 I7 170.4 112.2 83.16 65.70 51.72 42.39 30.68 18.79 17.43 2.070 1.827

0.9118 0,8800 0.8086 0.7245 0,1782 0.2097

1.0000 0.9938 0.9912 0.9817 0.9720 0.9621 0.9518 0.9388 0.9253 0.8982 0.8403 0.7773 0.6147 0.3048

facilitating the convergence of the triai solution. To permit direct comparison, the bubble point and dew point pressures recorded in Table IV for the volumetric measurements have been restated in Table V, with corresponding v a 1u e s c o mputed from the foregoing equations and the interpolated c o m p o s i t i o n d e t e r minations. The average deviations of the dew point and bubble point pressures p r e d i c t e d from Table 111 from comesponding values based upon the volumetric measurements were 0.82 and 0.38 pound per square inch, respectively. T h e m o l e fractions interpolated directly b y the residual methods which are presented in Figure I yield average deviations from the smoothed values o b t a i n e d from Table I11 of 0.32 and 0.25 pound per square inch for dew point and bubble point states. In all cases the agreement was within the corresponding differences between the experimental d a t a and the smoothed curves shown in Figures 2 and 3.

-

COMPRESSIBILITY FACTOR AND MOLAL VOLUME OF PROPENE-PROPANE MIXTURES (Continued)

Pressure, Lb./Sq. Inch Abs.

1633

m

493.0 361.5 179.0 118.2 87,727 69.43 54.78 45 00 32.76 20.43 14.18 7.473 2.779

Figures in parentheses represent dew point or bubble point pressures in pounds per square inch absolute. * Two-phase Dew point pressures for 10" a n d 40. F.obtained from smoothed data. region.

C

(Continued on page 16.94)

ACKNOWLEDGMENT

This w o r k w a s c a r r i e d out as a part of the activities of the Lummus Fellowship at the California Institute of Technology. Financial s u p p o r t from T h e L u m m u s Co. is acknowledged. Betty Kendall and Virginia Berry assisted with t h e c o m p u t a t i o n s . The assistance of F. E. Frey in clarifying certain portions of the manuscript was most helpful. NOMENCLATURE

K

= gas-liquid equilibrium

KR

=

constant, Y / X equilibrium constant predicted by Raoult's law, P " / P n = mole fraction of component in system R .R.IL - whole . . ... P = pressure, pounds per square inch absolute P" = vapor pressure of a component, pounds per square inch


1634

TABLE I V. Pressure, Lb./Sq. Inch Abs.

COMPRESSIBILITY

FACTOR AND

Compresibility Factor


MOL.4L VOLUME OF PROPENE-PROPANE

(Concluded) Compreasibility Factor

160' F.



190° F.

MIXTURE^ Volume Cu. Ft.) Lb. Mole

__-_

2200 F.

1,000 1,250 1,500

0.2364 0.2888 0.3397

1.572 1.535 1.506

0,2492 0.2987 0.3481

1,737 1.666 1.618

0,2777 0.3195 0,3643

1,750 2,000 2,250 2,500

0.3901 0.4403 0.4897 0.5380

1.483 1,464 1,448 1.431

0,3971 0.4452 0,4924 0.5393

1.582 1.552 1,526 1.505

0 4094 0.4548 0,4996 0.5443

1.707 1.659 1.620 1 . 588

2,750 3,000 3,500 4,000

0.5862 0.6339 0,7278 0.8199

1.418 1.405 1.383 1 363

0,5856 0.6317 0.7228 0.8113

1.485 1.468 1.440 1.414

0.5890 0.6334 0.7198 0.8053

1.562 1,540 1.500 1.469

4,500 5,000 6 000 7 000

:

0.9102 0.9988 1,1730 1.3451

1.346 1 328 1.300 1 278

0.8980 0.9834 1.1498 1.3148

1.391 1.371 1.336 1.310

0 8893 0.9723 1,1336 I , 2921

1.442 1.418 1.378 1.346

8,000 9,000 10,000

1 .j l l 5 1,6744 1.8379

1.257 1 237 1,222

1.4761 1 ,6358 1.7899

1.287 1,267 1.248

1 4481 1 6021

1 320 1.299 1.279

280' 0 14.696 20 40 60

80

100 125 150 200 300 400 600

-

F.

1 0000 0 9952 0 9930 0 9854 d'9780 0.9704 0.9628 0.9533

m

537.6 394,l 195.6 129.4 96.29 76.43 60.54

340° 1 . 0000 0.9962 0.9947 0 . 9892 0,9834 0.9778 0,9722 0,9650

F. m

581.8 426.9 212.2 140.6 104,9 83.44 66.25

0.9436 0.9242 0.8840 0,8417 0,7498 0.6454 0,5337 0.4478 0.4370

49.94 36,68 23.39 16.70 9 , 919 6.403 4.237 2 844 2.313

0.9577 0,9433 0.9138 0.8838 0.8217 0.7553 0.6892 0.6094 0.5770

54,79 40.48 26.14 18.96 11.75 8.103 5.914 4.184 3.301

1 750 2 000 2,250 2,500

0.4605 0,4942 0,5314 0.5694

2.089 1.961 1,875 1.808

0.5633 0.5707 0.5915 0,6173

2,762 2 449 2.256 2,119

2 750 3'000 3 500 4,000

0.6080 0.6467 0.7334 0.8051

1,755 1.711 1 ,663 1.598

0.6477 0.6800 0.7487 0,8184

2.021 1,945 1.836 1.756

4,500 6 000 6'000

7:OOO

0.8820 0.9581 1,1080 1.2564

1,556 1,521 1,466 1.425

0,8875 0.9561 1.0940 l,,2320

1,693 1.641 1,565 1.510

8,000 9.000 10,000

1,4005 1,5421 1.6827

1.390 1,360 1,336

1,3661 1.4969 1.6278

1,466 1.427 1.397

800

1,000 1,250 1,500

: :

TABLE V. COMPARISON O F BUBBLEPOINTA N D DEW POINT PRESSURES FROM VOLEMETRICA K D PHASE EQCILIBRIUM MEASCREMEXT~ Dew Point Bubble Point Compo- VoluCompo- VoluTemp., sitiona metricb sition" metrich OF. method method SmoothedC method method SmoothedC MOLEFRACTION PROPEXE, 0.2411 10 40 100

160 190

49.8 83.5 198.7 402.2 549.6

10 40 100 160 190

54.4 90.8 214.6 431.8 589.0

._. lQ8:O 401.3 549.0

49.8 83.3 198.7 401.7 549 9

50.4 84.3 200.1 403.9 551.1

50.6 84.3 199.8 403.8 551.0

50.4 84.0 200.0 403.2 551.3

54 4 91.4 215.5 432.6 590.0

54.6 91.1 215.9 433.1 589.2

MOLEFRACTION PROPENE, 0.6289

... 213:s 430.5 588.3

54.1 90 4 214.7 432.5 588.3

54.9 91.4 215.8 433.1 589.7

determined from measured composition of coexisting phases. * Values Values determined from directly measured bubbk or dew point pressures

for compositions in question. C

Computed from smoothed data of Table IV.

1 7537

2.026 1.865 1,772

Vol. 43, No. 7

X Y 6

Z

mole f r a c t i o n of a c o m p o n e n t in a liquid phase = mole f r a c t i o n of a component in a gas phase = deviation of experimental points from smooth curve = averagedeviation =

Subscripts 3 = propane I11 = propene 6 = bubblepoint d = dewpoint iz = componentk LITERATURE CITED

(11 Beattie, J. .4.,Kay, W.C., and Kaminsky. J., .r. Am. Chem. SOC., 59, 400' F. 1589-90 (1937). __ 1 0000 m (2) Beattie, J. A , , Poffen0 9972 626 0 berger, N., and Had0 9937 459 3 0 9913 228 B lock, C . , J . Chem. 0 9867 151 , Phys., 3, 96-7 (1935). 0 9823 113 3 90 21 0.9777 (3) Bridgeman, 0. C., J . Ana. 0 9722 71 76 Chem. Soc., 49, 1174-83 0,9664 59,44 (1927). 0,9552 44.06 (4) Dana, L. I., Jenkins, A. 0.8325 28.68 0.9103 21.00 C., Burdick, J. N., and 0.8667 13.32 Timm, R. C.. Refrig. 0.8219 9.478 0.7788 7.186 Eng., 12, 387-406 (1926). 0.7303 5,388 (5) Farrington, P. F., Sage, 0,6942 4.269 B. H., and Lacey, W , 0.6718 3.342 0.6627 3.057 h7.,IND.EKQ. CHEM., 0.6695 2.745 41, 1734-7 (1949). 0.6821 2.517 (6) Lewis, G. N., J . Am. C ~ ~ V J . 0.7001 2.349 SOC.,30, 668-83 (1908). 0,7244 2.228 0 7803 2.057 (7) Lewis, G. N., and Raii0.8400 1.937 dall, M., "Thermody0,9009 1.847 namics and the Free 0.9627 1.776 E n e r g y of Chemical 1.0884 1.674 1.2162 1.603 S u b s t a n c e s , " p. 209, Kew York, McGraw1 3406 1.546 1.4622 1.499 Hill Book Co., 1923. 1 . 5792 1.457 (8) McMillan, W. d., Cole, H. A. and Ritchie. A. J-.. I N D . ENG. CHhM., ASAL. ED., 8, 105 7 (1936). (9) Reamer, H. H., Sage, B. H., and Lacey, W. N., IA-D.E:sG. CHEM.,41, 482-4 (1949). (10) Sage, B. H., and Lacey, W. N., I h i d . , 40, 1299-301 (1948). (11) Sage, B. H., and Lacey, UT.N., Truns. A m . Insl. Mining M e t . EnQTS.,136, 136-67 (1940). (12) I h i d . , 174, 102-20 (1948). (13) Sage, B. H., Schaafsma. J. G., and Lacey, W. X., IND. ENG. CHEM.,26, 1218-24 (1934). (14) Seibert, F. M . , and Burrell, G. A , J . Am. Chern. Soc., 37, 2683-91 (1915). (15) T'aughan, W. E., and Graves, S . R . , IND.ENG. CHEM.,32, 1252-6 (1940). (16) Winkler, C. .A,, and Maass. O., Can. J . Research, 9, 610-12 11933). RECEIVED January 24, 1930

Volumetric and Phase Behavior of Propene-Propane System

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