Article Cite This: J. Chem. Eng. Data XXXX, XXX, XXX−XXX
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Measurements of PvT Properties, Saturated Densities, and Critical Parameters for 3,3,3-Trifluoropropene (HFO1243zf) Yukihiro Higashi† and Naoya Sakoda*,†,‡ †
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Research Center for Next Generation Refrigerant Properties (NEXT-RP), International Institute for Carbon-Neutral Energy Research (WPI-I2CNER) and ‡Department of Mechanical Engineering, Kyushu University, Fukuoka 819-0395, Japan ABSTRACT: Measurements of PvT properties, saturated densities, and critical parameters were carried out for a low-GWP refrigerant: 3,3,3-trifluoropropene (HFO1243zf, CF3CHCH2). Seventy-five PvT property data points along seven isochores around the critical point were obtained in the temperature range from 328 to 430 K, in the density range between 50 and 899 kg m−3, and at pressures up to 6.9 MPa by the isochoric method. Fourteen saturated densities were obtained by the observation of meniscus disappearance in the critical region. On the basis of these measurements, the critical parameters of Tc = 376.93 ± 0.01 K and ρc = 414 ± 3 kg m−3 were determined. The present results are compared to an available equation of state.
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INTRODUCTION In order to prevent ozone layer depletion and global warming, which are considered to be crucial global environment issues, searching for new alternatives to CFC (chlorofluorocarbon), HCFC (hydro-chlorofluorocarbon), and HFC (hydrofluorocarbon) refrigerants is our urgent and important task. Recently, HFO (hydrofluoroolefin) refrigerants such as 2,3,3,3-tetrafluoropropene (R1234yf, CF3CFCH2), trans-1,3,3,3-tetrafluoropropene (R1234ze(E), CF3CHCHF), and cis-1,3,3,3tetrafluoropropene (R1234ze(Z), CF3CHCHF) have attracted considerable attention as next-generation refrigerants for the working fluids of refrigerators and heat pump systems. However, only a few thermodynamic properties for the HFO refrigerants are available. The authors have already reported the experimental data of thermodynamic properties for some of HFO refrigerants, i.e., PvT properties, vapor pressures, saturated densities, critical parameters, specific heat capacities, and surface tensions for R1234yf,1−4 R1234ze(E),5−9 and R1234ze(Z). 10−13 3,3,3-Trifluoropropene (HFO1243zf, CF3CHCH2, molar mass = 96.05113 g mol−1) is also expected to be an alternative refrigerant for room air conditioners, although the flammability (A2 category in the ASHRAE classification of safety groups) is a concern for applications. Brown et al.14 measured the vapor pressure of HFO1243zf from 234 to 373 K in both the ITC-CNR and Polytechnic University of Marche, Italy laboratories. Di Nicola et al.15 measured PvT properties in the temperature range from 283 to 353 K and at pressures up to 35 MP in the liquid phase and those from 278 to 368 K and up to 0.9 MPa in the vapor phases. In addition, the saturated liquid-density correlation was also given from the liquid densities. Higashi et al.16 presented some vapor pressures, PvT properties, saturated densities, and critical parameters at an international conference, but these © XXXX American Chemical Society
numerical values had never been reported. On the basis of their experimental data, Akasaka17 formulated an equation of state (EOS) for HFO1243zf. Recently, the vapor pressures of HFO1243zf were measured by Higashi et al.18 in the temperature range from 310 to 377 K with the isochoric method adopted for the PvT property measurements. A vapor pressure correlation was made again on the basis of the obtained data from 310 to 377 K and the data by Brown et al.14 at lower temperatures to 234 K. Moreover, the critical pressure was also determined by the extrapolation of a new vapor pressure correlation. In this article, the measurement results of PvT properties, saturated liquid and vapor densities, and critical parameters for HFO1243zf are presented.
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EXPERIMENTAL SECTION Sample. A sample of HFO1243zf (CAS no. 677-21-4) was furnished by Mexichem, Ltd. U.K., and the sample purity was >0.995 in volume fraction. This sample was used without further purification. Measurements of PvT Properties. The PvT properties of HFO1243zf were measured by an isochoric method, and the experimental apparatus and procedures were described in our previous papers.19,20 The main part of this apparatus was composed of a stainless steel pressure vessel and a pressure transducer (Paroscientific, model 42K-101) that was calibrated with a dead-weight pressure gauge. The pressure vessel and pressure transducer are connected to each other and installed in a thermostated bath. Temperature was measured with a 25 Ω standard platinum resistance thermometer (Chino, model Received: June 1, 2018 Accepted: August 22, 2018
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DOI: 10.1021/acs.jced.8b00452 J. Chem. Eng. Data XXXX, XXX, XXX−XXX
Journal of Chemical & Engineering Data
Article
the mass of the sample and the inner volumes of three pressure vessels for each expansion procedure. As the uncertainty in the density measurements depends on the times of expansion, the claimed uncertainty in the density measurements was estimated to be within 0.03 to 0.32%.
R800-2) calibrated against ITS-90 and an AC thermometer bridge (Tinsley, model 5840). The thermometer was mounted near the pressure vessel at the same level in the thermostated bath. A digital multimeter, PID temperature controller, power supply, heater, and stirrer were used to keep the temperature of the heat-transfer medium constant. In the present measurements, silicone oil was used as the heat-transfer medium. To keep the temperature constant, four heaters were used: two main heaters and two subheaters. The difference between the set-point temperature and the measured temperature was detected by the thermometer bridge, and this signal was transferred to the PID controller through a digital multimeter. The output of the subheaters was adjusted against the temperature difference by the power supply. The uncertainty in the temperature measurements was estimated to be 5 mK (k = 2) including the uncertainty of the standard resistance thermometer, estimated to be 1 mK, and the temperature fluctuation in the thermostated bath in the vicinity of the pressure vessel, which was 3 mK. The uncertainty in the pressure measurements was estimated to be 1.0 kPa (k = 2) and was composed of the uncertainty in the pressure transducer of 1.0 kPa and the fluctuation in the pressure stability in the thermostated bath of
