Experimental study of PVT properties of HCFC-123(CHCl2CF3)

Fluid PhuseEqui~ibriu,80 (1992) 131-140 Elsevier Science Publishers B.V., Amsterdam

131

Experimental study of PV’Tproperties of HCFC- 123(CHCl,CF,) K. OguchP, M. Yamagishib and A.. Muranoa

bAnritsu Co. Ltd., Atsugi, Kanagawa(Japan)

Keywords: experiment, PVT properties, vapor pressure, HCFC-123, equation of state, correlation of vapor pressure

The PFT properties and vapor pressures of HCFC-~~(CHCl~CF~) have been experimentally determined in the range of temperatures from 253 K to 493 IS and pressures up to 17 MPa with a constant volume apparatus within the uncertainties of 5 mK and 2.2 kpa, respectively. The equation of state of this substance was correlated on the basis of the present experimental data and other available data in the form of the modified BWR equation in consideration of two conditions of Gibbs function and latent heat along saturation, and was compared with all of them. The correlation of vapor pressure was also formulated based on the experimental data in the range of temperatures above 253 K. All of the experimental data was converted into 1990 International Temperature Scale and was used for the correlation.

Since the CFCs have been regulated under the international agreement because of the ozone depletion and global warming, HCFC-123 (l,l-dichloro-2,2,2trifluoroethane, CHCl,CF,) is expected as an environmentally acceptable refrigerant and a prospective substitute for CFC-ll(trichloro-monofluoromethane, CC&F)

0378~S81!Y92/$05.00 01992 Elsevier Science PublishersB.V. All rights reserved

132

because it has low ozone depletion potential and low global warming potential by means of its short atmospheric life. This paper deals with the experimental study of PET properties and vapor pressure, the correlation of equation of state and of vapor pressure, and the comparisons of the issued data with these correlations.

SURVEY OF EXPERIMENTAL

STUDY

PVT properties The experimental studies of PVT properties were conducted in a wide range of the state parameters as shown in TABLE 1. In the superheated vapor region, the experimental works of PVT properties were measured by Takahashi et a1.(1991), Sakakibara(l990) and Weber(1990). In the compressed liquid region, the

TABLE 1 PVT properties for HCFC-123 First author

Takahshi Matsuo Maezawa Fiao Fukushima Sakakibara Weber Morrison Takagi

Temperature (K)

Pressure (MPa)

Density (kg/m3)

Range

Uncertainty

Range

Uncertainty

Range

323 -423 293 -353 280 -340 311 -523 352 -484 370 -420 358 -453 280 -363 333 -448

---

0.1 -2.0 0.1 -38.8 0.5 -2.0 0.6 -12.0 0.5 -5.2 0.1 -1.9 0.3 -2.0 0.3 -3.8 0 -45.0

---

4.45 -133 1309 -1554 1349 -1510 96 -1440 29 -1030 5.7 -124 18 -103 1270 -1510 900 -1500

--0.015 0.010 0.020 0.010 0.001 0.001 0.1

--0.007 0.002 0.005 0.0008 0.0002 -0.002 0.0015 0.2

Uncertainty(%)

Number of data

Purity of sample

---

48

---

---

46

---

0.2

16

0.15

134

0.2

59

0.7

40

---

--

---

69

0.3

--

99.93 (wt%) 99.8 (wt%) 99.8 (%) 99.8 (wt% ) 99.95 (wt%) 99.9 (%) 99.8 (wt%)

133

experimental studies of PVT properties were conducted by Maezawa et a1.(1990), Matsuo et a1.(1989) and Morrison et a1.(1990) In the entire fluid phase covering the superheated vapor and the compressed liquid, the PVT property measurements have been completed by Piao et a1.(1991) and Fukushima et a1.(1990a) Vapor pressure The available experimental studies of vapor pressure of this substance cover a temperature range 273 - 457 K as tabulated in TABLE 2. Most data of vapor pressure agree well in the range of temperatures above 320 K.

TABLE 2 Vapor pressure for HCFC-123 First author

YeJU

Temperature Range

Yamashita

1989

Maezawa

1990

Piao

1989

Fukushima

1990

Weber

1990

Morrison

1990

EXPERIMENTAL

(K)

Uncertainty

273 -453 280 -350 313 -457 314 -457 338 -453 301 -373

0.05 0.01s 0.01 0.02 0.01 0.001

Pressure (MPa) Range 0.03 -3.46 0.05 -0.44 0.15 -3.67 0.16 -3.67 0.33 -3.46 0.10 -0.78

Uncertainty

Number of data

Purity of sample

0.003

39

99.5

0.007

8

0.002

69

W) 99.8

0.00s

65

(&) 99.8

0.0002

44

(!) 99.9s

0.001s

9

W) 99.93

@@J) 99.99 (WC%)

APPARATUS

A schematic view of the experimental set-up is shown in Fig. 1. A constantvolume method with a spherical vessel(A) of approximately 270 cm3 in its inner volume has been used for the present measurements of PVT properties as well as vapor pressure. The PVT property values of the sample have been determined by measuring precisely the relations between temperature and pressure along each The prescribed amount of the sample has been charged in a isochore. piezometer(A), while controlling carefully the temperature in a thermostated bath(F).

134

,V

P3

V

A: 8: c: D: E: F: G: Hl:

Piezometer (about 270 cm3 in its inner volume) Differential pressure gage Transformer bridge Platinum resistance thermometer Thermomeler bridge (Leeds & Northrup, ER8079) Thermostated bath Nitrogen bottte Heater

H2: I: J: Pl: P2: P3: Vl: V:

Cooler Pressure controller Circular pump or stirrer Air piston gage (Ruska 2465, up to 5 MPa) Air piston gage (Ruska 2470, up to 17 MPa) Mercury manometer Diaphragm type high pressure valve High pressure valves

Fig. 1 Schematic diagram of the P-V-2’ apparatus

Temperature was measured with the use of a platinum resistance thermometer(D) calibrated within 2 mK at the National Research Laboratory of Metrology in Japan, based on the International Practical Temperature Scale(1968) and converted into the International Temperature Scale(1990). The piezometer is connected to a membrane type differential pressure balance detector(B) through a packingless membrane type high pressure valve(W); the pressure of the sample is determined by balancing it with the pressure of nitrogen, using the deflection of the membrane as a sensitive indicator of the pressure difference. The membrane of the differential pressure detector in the the~os~ted bath is hori~ntally installed at the same level as the center of the spherical vessel so as to minims hydrostatic pressure difference corrections, Pressure was measured with the aid of two air piston gages(P1, P2) and mercury manometer(P3), depending on the pressure range. Density was determined by means of dividing a mass of the sample by the whole volume of filling a sample including a spherical vessel, a high pressure valves, pipings and so on. The uncertainties of temperature, pressure and density measurements are

135

estimated to be 5 mK, 2.2 kPa and 0.01 %, respectively. The sample was furnished by Mitsui-du Pont Fluorochemical Co., Ltd., and it was composed of 99.8 wt% purity.

EXPERIMENTAL

RESULTS

PVT properties Measurements of PVT properties of HCFC-123 were made along 5 isochores in the range of temperatures from 352 K to 493 K, pressures up to 16.43 MPa and densities from 280 kg/m3 to 1317 kg/m3, as shown in TABLE 3.

TABLE 3 Experimental data of PVT property for HCFC-123 Pressure @W 3.6734 4.0350 4.6983 5.2413 5.8497 0.8124 1.3513 2.9027 3.9460 6.5997 9.1619 11.7625 14.357s 16.4300 2.5228 4.8508 7.2218 9.6109

Density 0 545.71 545.53 545.20 544.93 544.63 1316.99 1316.91 1316.65 1316.48 1316.05 1315.63 1315.21 1314.78 1314.44 1048.89 1048.27 1047.65 1047.03

Temperature

Pressure

0

@@aI

457.026 463.115 474.141 483.112 493.113 352.123 353.13s 356.131 358.121 363.208 368.124 373.122 378.121 382.121 423.137 433.118 443.130 453.112

12.0201 14.4433 3.0482 3.5758 4.419s 5.2749 5.9150 7.0122 8.7770 3.2252 3.3299 3.4340 3.4693 3.4692 3.6066 3.7404 3.8739

Density (kg/m31 1046.40 1045.76 942.30 942.13 941.86 941.58 941.38 941.04 940.49 280.35 280.30 280.24 280.22 280.22 280.15 280.07 280.00

Temperature (K) 463.111 473.128 439.954 443.122 448.120 453.119 456.821 463.114 473.113 449.462 453.119 456.819 458.111 458.112 463.108 468.081 473.113

136

Vapor pressure Measurements of vapor pressure of HCFC-123 have been conducted along 4 isochores in the range of temperatures from 243 K to 453 K and pressures from 7.1 kPa to 3.45 MPa as shown in TABLE 4. For such wide pressure range, one air piston gage and mercury manometer have been used in each appropriate pressure range. And the pressure difference caused by the pressure gages were checked by measuring vapor pressures at the same temperatures of 313.136 K, 313.140 K and 313.143 K. On the other hand, HCFC-123 contains the hydrogen atom and will be decomposed at high temperature. Therefore, measurements along the isochore of approximately 550 kg/m3 were conducted while temperatures were controlled

TABLE 4 Experimental data of vapor pressure for HCFC--123 Ser.

Temperature @I

1

243.153 248.155 253.155 258.154 263.157 268.150 268.151 273.140 278.148 283.151 288.147 288.149 293.143 303.144 303.144 313.136 313.136 313.140 313.141 313.143 313.143 323.141 333.135

Pressure

Gage’

Ser.

@PaI 0.0071 0.0096 0.0129 0.0167 0.0212 0.0271 0.0264 0.0339 0.0421 0.0519 0.0634 0.0634 0.0766 0.1101 0.1104 0.1551 0.1549 0.1559 0.1557 0.1557 0.1558 0.2137 0.2868

Temperature WI

P3 P3 P3 P3 P3 P3 P3 P3 P3 P3 P3 P3 P3 P3 P3 Pl P3 Pl P3 Pl P3 Pl Pl

‘Note; Pl: Air piston gage, P3: Mercury manometer

1

3

4

5

333.136 343.139 353.132 363.125 373.127 383.125 393.122 403.119 413.119 423.116 433.115 443.111 453.120 333.167 373.126 413.113 323.137 333.171 373.135 373.126 403.144 443.109 447.914

Pressure

Gage’

(MPa) 0.2868 0.3782 0.4900 0.6249 0.7861 0.9765 1.1991 1.4580 1.7565 2.0989 2.4904 2.9373 3.4503 0.2869 0.7869 1.7567 0.2133 0.2866 0.7857 0.7852 1.4583 2.9357 3.1720

Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl Pl

137

up-wards or down-wards between 243 K and 473 K in several times, and the measured pressures were compared with one another. Those results were also shown in TABLE 4.

CORRELATION Equation of state

In the present study, the reliable experimental data were evaluated and selected from the PVT property data sources listed in TABLE 1. And for developing the present formulation, the correlations for the saturated liquid and vapor density were formulated and used for the calculation of the supplementary data. Temperatures of the selected and supplementary data were converted into 1990 International Temperature Scale. Besides these data, the equation of state has been developed with the aid of the least squares fitting under the conditions that the first and second derivatives of the critical isotherm being zero at the critical point; that Gibbs functions of the saturated liquid and vapor are consistent; and that enthalpy difference between the saturated liquid and vapor is equal to the latent heat calculated from the Clausius-Clapeyron equation. Critical parameters used in the present study were the recommended values in the book(1991). The critical temperature was adopted 456.821 K which was a converted value into 1990 International Temperature Scale. The equation of state developed in the present study is expressed as follows;

’

P =-_=z RTp

P, =TrPr

= 1+ A,++++++) (

+pr2E

8

xp

r2+(As+$++]

r

P r3

[( +A19

E=e

P .+A~P

7

s+

& Tr3

A21 +Tr4

(PI p ,2) , Zc=Pc/

I

Prlo

(RTcPc)

1 , Pr=P/Pc.

(1) Tr=T/Tc.

P

r=P/P

c

138

the numerical constants, the values of the critical parameters and gas constant are given in TABLE 5. The effective region of this equation of state is a whole region of parameters shown in TABLE 1.

where

TABLE 5 Numerical Constants in Eq.(l) A,=

2.063005620x10-’

AI0= 1.171054584x10- 2

A,= -6.552493744 A,= 6.2OOh11643 A 4=-3.075567727 A,= 2345858913x10-’ A,= -4.222163401x10-’ A,= 2.219322328 A,= -3.244812398 A.= 4.547374591xlk’

&= -8.292299158x10-’ A12= 1.396531836x1O-2 A,= 1.074807507 AM= -1.775930514x10-’ 1.496883162 &= A16= 4.918992603x10-’ A,,= 2.415013030x10-’ A..= -4.639941481x10-’

A,,= -2.383986748x10-’ A,= 6.536252810x10-3 Azl= -2.120507745x10” a= -7.5x10-1

R= 5.436768584x10-’ PC= 3.666 p,= 5.55x102 Z’,= 4.56821~10~ Z_= 2.659577007x10-’

kJ@gK) Mpa kg/m3 K

Correlation of vapor pressure The vapor pressures were correlated with an aid of the least squares fitting, giving the equal weights to all data listed in TABLE 2. Temperatures were converted into 1990 International Temperature Scale. The correlation of vapor pressure thus developed in the present study is expressed as follows; 1 n (P,) *=Bl l +(P,) .=P./P,,

I

1 1+B2

(

1 --T,) +BJ ( 1 --T,) 1.5+l34 ( 1 -T,)3

(2)

T.=T/T.

B,=-2.445640416x10’,

B,=7.065886819, B,=2.219202643x101,

B,=5.037025097

The whole region listed in TABLE 2 is effective.

DISCUSSION The mean density deviations of the available PVT property data from Eq.(l) are

139

calculated in the effective region as follows; 1.34%(21%max.) for the data by Fu~sh~a et ~.(19~b); l.O2%(2O%m~.) for the data by Piao et al(1991); 0.1~(0.2O%m~.) for the data by Matsuo et aI(1989); 0.53%(1.l%max.) for the data except a single isotherm by Sakakibara(l990); 1.74%(8.9%max.) for the data except a single isotherm by Takahashi et al(1991); 0.084%(0.17%max.) for the data by Maezawa et al(1990); 0.04%(0.07%max.) for the data by Morrison et al(1990); 0.61%(~0.6%m~.) for the data by Weber; and l.l1%(17%m~.) for the present data. The density deviation is usually large in the vapor region, whereas small in the liquid region. The mean pressure deviations of them from IQ.(l) are also calculated as follows; 0.70%(2.55%max.) for the data by Fukushima et al.(199Ob);1.23%(53%max.) for the data by Piao et al.(1991); 14% for the data by Matsuo et al(1989); 0.47%(0.92%m~.) for the data except a single isotherm by S~~bara(l990); 1.36%(7%max.) for the data except a single isotherm by Takahashi et al(1991); 11.3%(38%max.) for the data by Morrison et al.(1990); 0.51%(8%max.) for the data by Weber(1990); and 2.12%(23%max.) for the present data. In the compressed liquid region, the pressure deviation of the data becomes significantly large at lower pressures.

CONCLUSION The experimental data of PVZ’properties and vapor pressure of HCFC-123 have been observed in the present paper. And also the equation of state and the ~r~lation of vapor pressure for HCFC-123 were fo~ulated based on the available measured data in the wide range of temperatures and pressures.

ACKNOWLFDGEMENT The authors are greatly indebted to the National Research Laboratory of Metrology, Ibaraki, Japan, for the calibration of the thermometer; and to Mitsui-du Pont Fluorochemicals Co., Ltd., Tokyo, for furnishing and analyzing the sample of HCFC-123. The assistance of Messrs. Tomonari Sakuma, Noboru Sakurai, Yoshio Simizu and Yoshinobu Togo, who conducted the experiments with the present authors, and of Dr. Naoyuki Yada and Mr. Tomoaki Sato, who helped in hanging the present text, is gratefully acknowledged. Financial support of the Grantin-Aid for Scientific Research Fund by Ministry of Education, Science and Culture (Project No. 03650194) is also gratefully acknowledged.

Fukushima, M., Watanabe, N. and Kamiiura, T., 199Oa, Measurements of the Vapor-Liquid Coexistence Curves and the Critical Parameters of HCFC123 and HFC134a, Trans. ofthe JAR, 7(2), 85-95(in Japanese, with English abstract). Fukushima, M., Watanabe, N. and Kamimura, T., 199Ob, Measurements of the PVT Properties of HCFC123 and HPC134a, Trans.ofthe JM, 7(3), 243-256(in Japanese, with English abstract). Japanese Association of Refrigeration and Japan Flon Gas Association, 1991. Zkwnophysical Propertiesof EnvironmentallyAcceptable Fluorocarbons - HFC-134a and HCFC-123 -. JAR and JFGA, Tokyo, 255 pp. Maexawa, Y., Sate, H. and Watanabe, K, 1990, Saturated liquid densities of HCFC-123 and HFC-134a, Journul of tire drill and Engineering Da&z,35(3), 225-228. Matsuo, N., personal ~~u~~n, 1989. Morrison, G. and Ward, D. IL, personal communication, 1990. Piao, C-C., Sate, H. and Watanabe, K, 1991, PVT and Vapor Pressure Measurem ems on l,lDichioro-2,2,2-trifluoroethane(H~~-123), Journal of the Chemical and Engineering Dam, 36(4), 398-403. Sakakibara, EC,1990, M.S.Thesis, Keio University, Yokohama@ Japanese with English abstract). Takagi, T., 1991, Ultrasonic Speed for Liquid Trichlorofluoromethane and l,l-Dichloro-2,2,2trifluoroethane at Temperatures from 283 to 373 K and Pressures up to 75 Mea, Juumal oftie Chemical and Engineering Data, 36(4), 394-398. Kwagzii, A., and Takahashii S., 1991, Viscosity of Saturated Liquid Fluorocarbon Refrigerants from 273 to 353 K, fnternafionaiJournal of Ihermophysics, 12(l), 105-117. Weber* LA., 1990, , Jottmal of tire CIiemicaland Engineeritig Da&z,35(3), 237-240. Yam&&a, T., Kubota, H, Tanaka, Y., Makita, T. and Kashiwagi, H., 1989, Physical Properties of New Halogen&d Hydrocarbons, Proceedings of the l&h Japan sympOium on ~er~~hys~~ Properties, 75-78(in Japanese with English abstract).