Vapor Phase PvTx Measurements of Binary Blends of 2,3,3,3

Article pubs.acs.org/jced

Vapor Phase PvTx Measurements of Binary Blends of 2,3,3,3-Tetrafluoroprop-1-ene + Propane and cis-1,2,3,3,3Pentafluoroprop-1-ene + Propane J. Steven Brown,† Gianluca Coccia,‡ Giovanni Di Nicola,*,‡ Mariano Pierantozzi,§ and Fabio Polonara‡ †

Department of Mechanical Engineering, The Catholic University, Washington, DC 20064, United States Dipartimento di Ingegneria Industriale e Scienze Matematiche, Università Politecnica delle Marche, via Brecce Bianche 12, 60131 Ancona, Italy § Scuola di Ateneo Architettura e Design, Università degli studi di Camerino, Ascoli Piceno 63100, Italy ‡

ABSTRACT: The paper presents 86 PvTx measurements in the vapor phase for blends of 2,3,3,3-tetrafluoroprop-1-ene (R1234yf) and propane and 62 PvTx measurements in the vapor phase for blends of cis-1,2,3,3,3-pentafluoroprop-1-ene (R1225ye(Z)) and propane. The R1234yf and propane blends were measured along four isochores (0.047, 0.048, 0.072, 0.095) m3·kg−1 for (268 < T < 363) K for four propane mole fractions (0.230, 0.505, 0.611, 0.709) mol·mol−1. The R1225ye(Z) and propane blends were measured along five isochores (0.032, 0.038, 0.042, 0.067, 0.090) m3·kg−1 for (303 < T < 363) K for five propane mole fractions (0.225, 0.516, 0.593, 0.690, 0.855) mol·mol−1. The data are well-predicted when fitted (1) with Fundamental Helmoltz Equations of State (EoS), Peng−Robinson EoS, and Extended Corresponding States EoS when each are coupled with a modified van der Waals one-fluid linear mixing model, and (2) with a truncated Virial EoS.

■

INTRODUCTION Recently, much pressure has been brought to bear on limiting the use of hydrofluorocarbon (HFC) working fluids because of their high global warming potentials (GWPs). For example in 1997, the Kyoto Protocol set emissions targets for HFCs by country.1 The European Union (EU) formerly adopted the Kyoto Protocol in 20022 and in 2006 adopted the first so-called F-Gas regulations aimed at regulating HFCs.3 At the same time, the EU also adopted the Mobile Directive, which banned the use of refrigerants with GWPs greater than 150 in automotive air conditioning applications in all vehicles beginning in 2017.4 More recently, the EU repealed the 2006 F-Gas regulations and adopted in their place more stringent F-Gas regulations.5 In addition to the previously mentioned examples, some countries (e.g., Denmark, Norway, Slovenia, and Spain) tax HFC refrigerants and others have proposed regulating HFCs under the Montreal Protocol framework.6 Although the above discussion is not complete, it is clear that there is an ever-increasing desire by a wide-ranging diversity of interested partiesfor example, governments, nongovernmental organizations, regulatory bodies, industry, and the public at largeto limit and minimize the negative environmental impacts of HFC working fluids. Beginning just over 10 years ago, the industry began seeking in earnest commercially viable, low-GWP working fluids, partly as a response to the EU Mobile Directive.4 As part of this effort, the industry began developing halogenated propene isomers, among other types of chemicals, with two halogenated propene isomers, R1234yf (2,3,3,3-tetrafluoroprop-1-ene) and R1234ze(E) © XXXX American Chemical Society

(trans-1,3,3,3-tetrafluoroprop-1-ene), having reached the commercialization stage. In fact, both are in current use in various applications. In addition to the two previously mentioned working fluids, others being considered include R161 (fluoroethane), R1233zd(E) (trans-1-chloro-3,3,3-trifluoroprop-1-ene), R1234ze(Z) (cis-1,3,3,3-tetrafluoroprop-1-ene), and R1336mzz(Z) (cis-1,1,1,4,4,4-hexafluorobut-2-ene), just to name a few. The present paper forms part of the ongoing work7−9 by the authors to seek low-GWP blends appropriate for air-conditioning and refrigeration applications. The number of low-GWP single-component working fluids appropriate for these applications is limited.10 Thus, it is becoming increasingly more important to identify appropriate blends of working fluids since the thermodynamic and transport properties of blends may be able to be “tailored” for particular applications, while at the same time allowing for the minimization of the overall GWP and allowing for the “adjustment” of the blend’s safety characteristics, for example, flammability and toxicity, in order to meet the needs of the end-user and application. In addition, by including hydrocarbons in blends containing low-GWP unsaturated halocarbon working fluids, both lubricant solubility characteristics and heat exchangers performance can potentially be improved. Finally, there also is scientific interest in investigating low-GWP blends consisting of many different types of working fluids. Received: May 14, 2016 Accepted: July 29, 2016

A

DOI: 10.1021/acs.jced.6b00396 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 1. Propane, R1234yf, and R1225ye(Z) Sample Descriptions chemical name

a

source

initial mole fraction purity

propane

Ausimont, Italy

0.999

R1234yfa

Arkema, France

0.9995

R1225ye(Z)b

Mexichem Fluor S.A. de C.V.

>0.97

purification method

final mole fraction purity

analysis method

0.9995

GC

0.9997

GC

>0.98

GC

several cycles of freezing, evacuation, melting, and ultrasonic agitation several cycles of freezing, evacuation, melting, and ultrasonic agitation several cycles of freezing, evacuation, melting, and ultrasonic agitation

2,3,3,3-Tetrafluoroprop-1-ene. bcis-1,2,3,3,3-Pentafluoroprop-1-ene.

Table 2. PvTx Data in the Vapor Phase for Binary Blends of R1234yf and Propanea T/K

P/kPa

v/m3·kg−1

T/K

xC3H8 = 0.230

P/kPa

Table 2. continued T/K

v/m3·kg−1

449.0 459.2 470.2 479.7 489.4 499.1 508.7 518.3 527.8 537.3 546.7 556.2 565.8 575.1 584.5 593.8 xC3H8 = 0.505

0.048 0.048 0.048 0.048 0.048 0.048 0.048 0.048 0.048 0.048 0.048 0.048 0.048 0.048 0.048 0.048

288.13 293.17 298.15 303.15 308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15 348.14 353.15 358.15 363.15

614.2 628.3 642.2 656.1 669.8 683.5 697.1 710.9 724.4 737.9 751.3 764.6 778.0 791.3 804.5 817.7 xC3H8 = 0.709

0.047 0.047 0.047 0.047 0.047 0.047 0.047 0.047 0.047 0.047 0.047 0.047 0.047 0.047 0.047 0.047

278.15 283.15 288.15 293.15 298.15 303.15 308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 363.15 278.15 283.15

366.9 374.9 382.8 390.7 398.5 406.7 414.4 422.1 429.8 437.5 445.3 452.9 460.5 468.1 475.6 483.2 490.8 498.3 366.9 374.9 xC3H8 = 0.505

0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072 0.072

268.15 273.15 278.15 283.15 288.16 293.15 298.15 303.15 308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 363.15

333.0 340.4 347.7 354.8 362.0 369.3 376.6 383.9 391.0 398.2 405.3 412.4 419.5 426.6 433.8 440.8 447.9 454.9 462.0 469.0

0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095 0.095

298.15 303.15 308.15 313.15 318.15 323.15 328.15 333.15 338.15

807.3 825.7 844.0 862.2 880.3 898.3 916.2 934.0 951.8

0.047 0.047 0.047 0.047 0.047 0.047 0.047 0.047 0.047

v/m3·kg−1

T/K

P/kPa

v/m3·kg−1

xC3H8 = 0.505

xC3H8 = 0.611

288.16 293.15 298.15 303.15 308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 363.15

P/kPa

343.15 348.15 353.15 358.15 363.16

969.5 987.1 1004.6 1022.2 1039.6

0.047 0.047 0.047 0.047 0.047

a

Standard uncertainties are u(T) = 0.03 K, u(P) = 1 kPa, u(v) = 0.005 m3·kg−1, and U(z) at the 95% confidence level = 0.001 mol·mol−1

In this paper, thermodynamic properties in the vapor phase for binary blends of three low-GWP refrigerants (R1234yf, R1225ye(Z), and propane) are reported. In addition, simple models are presented to describe the PvTx behaviors in the vapor phases of the blends.

■

EXPERIMENTAL SECTION Materials. Table 1 provides details for the tested samples of R290 (propane, CH3CH2CH3, CAS number 74-98-6), R1234yf (2,3,3,3-tetrafluoroprop-1-ene, CF3CFCH2, CAS number 754-12-1), and R1225ye(Z) (cis-1,2,3,3,3-pentafluoroprop1-ene, CF3CFCHF, CAS number 677-21-4). The samples were subjected to several cycles of freezing, evacuation, thawing, and ultrasonic stirring to remove noncondensable gases. Experimental Apparatus and Procedure. The system comprised an isochoric sphere, hardware to measure temperature, pressure, and mass, a controller, a data acquisition system, and two thermostatic baths. Because the experimental apparatus and procedure have been described,7,8 only a summary is presented below. The isochoric sphere and pressure transducer were immersed in either a low temperature bath with an operating temperature range of approximately from (210 to 290) K or a high temperature bath with an operating temperature range of approximately from (290 to 360) K. Because estimations of uncertainties of the entire measurement system are relatively complex, we refer the reader to previous articles,11,12 which describe in detail the methodologies and procedures used. In particular, uncertainties associated with measurements of temperature, pressure, specific volume, volume, mass, and density are reported by Giuliani et al.,11 who also describe the effects of temperature and pressure on cell volume. To briefly summarize, the expanded uncertainty with 95% level of confidence of the 25 Ω platinum resistance thermometer (Hart Scientific 5680) used to make the bath temperature measurement was 0.03 K. The expanded uncertainty with 95% level of confidence of the Ruska 7000 pressure transducer used to make the pressure measurement was 0.18 kPa. However, because of fluctuations in the bath temperature, the total expanded uncertainty with 95% level of confidence for the pressure measurement was 1 kPa. B



Article

Table 3. continued T/K

P/kPa

v/m3·kg−1

T/K

P/kPa

v/m3·kg−1

xC3H8 = 0.593 343.15 348.15 353.15 358.15 363.15

848.1 863.4 878.7 893.9 909.0

0.038 0.038 0.038 0.038 0.038

a Standard uncertainties are u(T) = 0.03 K, u(P) = 1 kPa, u(v) = 0.005 m3·kg−1, and U(z) at the 95% confidence level = 0.001 mol·mol−1

Figure 1. Vapor phase PvTx data (Table 2) for binary blends of R1234yf and propane: ●, xC3H8 = 0.709 and v = 0.095 m3·kg−1; O, xC3H8 = 0.505 and v = 0.072 m3·kg−1; ■, xC3H8 = 0.230 and v = 0.048 m3·kg−1; △, xC3H8 = 0.611 and v = 0.047 m3·kg−1; ▲, xC3H8 = 0.839 and v = 0.047 m3·kg−1.

Table 3. PvTx Data in the Vapor Phase for Binary Blends of R1225ye(Z) and Propanea T/K

P/kPa

v/m3·kg−1

T/K

0.042 0.042 0.042 0.042 0.042 0.042 0.042 0.042 0.042 0.042 0.042 0.042

308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 363.15

xC3H8 = 0.225 308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 363.16

491.5 501.4 511.5 521.2 531.1 540.8 550.6 560.3 570.0 580.1 589.7 599.3

412.6 420.3 428.0 435.7 443.4 451.0 458.7 466.6 474.1 481.7 489.3 496.8

v/m3·kg−1

xC3H8 = 0.690

xC3H8 = 0.516 308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 363.15

P/kPa 946.2 968.3 990.1 1011.5 1033.0 1054.4 1075.7 1096.9 1118.0 1139.2 1160.0 1180.9

0.032 0.032 0.032 0.032 0.032 0.032 0.032 0.032 0.032 0.032 0.032 0.032

Figure 2. Vapor phase PvTx data (Table 3) for binary blends of R1225ye(Z) and propane: ●, xC3H8 = 0.516 and v = 0.067 m3·kg−1; O, xC3H8 = 0.855 and v = 0.090 m3·kg−1; ■, xC3H8 = 0.255 and v = 0.042 m3·kg−1; △, xC3H8 = 0.593 and v = 0.039 m3·kg−1; ▲, xC3H8 = 0.690 and v = 0.032 m3·kg−1.

xC3H8 = 0.855 0.067 0.067 0.067 0.067 0.067 0.067 0.067 0.067 0.067 0.067 0.067 0.067

303.15 308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15 358.15 363.15

459.8 468.5 477.3 486.0 494.7 503.4 512.1 520.9 529.5 538.1 546.7 555.3 563.9

0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090 0.090

Figure 3. Deviations (ΔP/P = (Pcalc − Pexp)/Pexp) between the Ideal Gas Law (Pcalc) and the data of Table 2 (Pexp) for binary blends of R1234yf and propane: ●, xC3H8 = 0.709 and v = 0.095 m3·kg−1; O, xC3H8 = 0.505 and v = 0.072 m3·kg−1; ■, xC3H8 = 0.230 and v = 0.049 m3·kg−1; △, xC3H8 = 0.611 and v = 0.047 m3·kg−1; ▲, xC3H8 = 0.839 and v = 0.047 m3·kg−1.

xC3H8 = 0.593 303.15 308.15 313.15 318.15 323.15 328.15 333.15 338.15

722.5 738.6 754.6 770.3 786.1 801.7 817.3 832.7

0.038 0.038 0.038 0.038 0.038 0.038 0.038 0.038

Because of the complex volume of the isochoric cell, its total volume (including tubing, pressure transducer cavity, and magnetic pump volumes) was calibrated using a classical Burnett procedure, using helium as the reference fluid.13 After estimating the apparatus constant N = (V1 + V2)/V1 (where V1 and V2 are the isochoric and auxiliary cell volumes, respectively), V2 was C



Article

Figure 4. Deviations (ΔP/P = (Pcalc − Pexp)/Pexp) between the Ideal Gas Law (Pcalc) and the data of Table 3 (Pexp) for binary blends of R1225ye(Z) and propane: ●, xC3H8 = 0.516 and v = 0.067 m3·kg−1; O, xC3H8 = 0.855 and v = 0.090 m3·kg−1; ■, xC3H8 = 0.255 and v = 0.042 m3·kg−1; △, xC3H8 = 0.593 and v = 0.039 m3·kg−1; ▲, xC3H8 = 0.690 and v = 0.032 m3·kg−1.

Figure 6. Deviations (ΔP/P = (Pcalc − Pexp)/Pexp) between P−R EoS (Pcalc) for R1234yf and propane developed by the authors plus a modified van der Waals one-fluid linear mixing model,21 where the constants Kt = 1.01 and Kv = 0.95 and the data of Table 2 (Pexp): ●, xC3H8 = 0.709 and v = 0.095 m3·kg−1; O, xC3H8 = 0.505 and v = 0.072 m3·kg−1; ■, xC3H8 = 0.230 and v = 0.049 m3·kg−1; △, xC3H8 = 0.611 and v = 0.047 m3·kg−1; ▲, xC3H8 = 0.839 and v = 0.047 m3·kg−1.

Figure 5. Deviations (ΔP/P = (Pcalc − Pexp)/Pexp) between default highaccuracy EoS based on reduced molar Helmholtz free energy for R1234yf18 and propane19 plus a modified van der Waals one-fluid linear mixing model,21 where the constants Kt = 1.01 and Kv = 0.97 and the data of Table 2 (Pexp): ●, xC3H8 = 0.709 and v = 0.095 m3·kg−1; O, xC3H8 = 0.505 and v = 0.072 m3·kg−1; ■, xC3H8 = 0.230 and v = 0.049 m3·kg−1; △, xC3H8 = 0.611 and v = 0.047 m3·kg−1; ▲, xC3H8 = 0.839 and v = 0.047 m3·kg−1.

Figure 7. Deviations (ΔP/P = (Pcalc − Pexp)/Pexp) between ECS EoS (Pcalc) for R1234yf and propane developed by the authors plus a modified van der Waals one-fluid linear mixing model,21 where the constants Kt = 1.01 and Kv = 0.87 and the data of Table 2 (Pexp): ●, xC3H8 = 0.709 and v = 0.095 m3·kg−1; O, xC3H8 = 0.505 and v = 0.072 m3·kg−1; ■, xC3H8 = 0.230 and v = 0.049 m3·kg−1; △, xC3H8 = 0.611 and v = 0.047 m3·kg−1; ▲, xC3H8 = 0.839 and v = 0.047 m3·kg−1.

measured by filling it with distilled water (refer to Giulani et al.11 for the detailed procedure.) The volume of the isochoric sphere, tubing, and pressure transducer cavity was measured as 273.5 cm3 at 298 K with an expanded uncertainty at a 95% level of confidence of 0.3 cm3. The test samples (blends of working fluids) were prepared based on a gravimetric analysis. To minimize uncertainties in the mass measurements, the pure fluids first were charged into containers with known tare masses. An analytical balance with an uncertainty of 0.3 mg then was used to measure the combined masses of the containers and samples. The isochoric sphere and tubing were placed under vacuum and then charged with the desired amounts of the working fluids by connecting the sphere

to the appropriate containers. At the end of the charging process, the containers were once again weighed and the fluid masses remaining in the tubing were estimated. The difference between the discharged masses and the estimated masses remaining in the tubing was taken as the total sample mass. The expanded uncertainties with 95% levels of confidence for the molar fraction (x) and specific volume are 0.001 mol·mol−1 and 0.005 m3·kg−1, respectively. Once the bath temperature reached the desired set temperature, a mixing pump was activated for approximately 15 min, after which the test sample was allowed to stabilize for approximately 20 min. The test sample temperature and pressure then were measured, after which the thermostatic bath was changed to the next desired set temperature. D



■

Article

RESULTS AND DISCUSSION

Experimental Data. Table 2 and Figure 1 report 86 PvTx data in the vapor phrase for binary blends of R1234yf and propane. Five data sets were measured along four isochores (0.047, 0.048, 0.072, 0.095) m3·kg−1 for (268 < T < 363) K for four propane mole fractions (0.230, 0.505, 0.611, 0.709) mol·mol−1. Table 3 and Figure 2 report 62 PvTx data in the vapor phase for binary blends of R1225ye(Z) and propane. Five data sets were measured along five isochores (0.032, 0.038, 0.042, 0.067, 0.090) m3·kg−1 for (303 < T < 363) K for five propane mole fractions (0.225, 0.516, 0.593, 0.690, 0.855) mol·mol−1. The temperature and pressure ranges were chosen to represent typical thermodynamic spaces in the vapor phase for comfort cooling applications. Ideal Gas Model. Figure 3 and Figure 4 show deviations (ΔP/P = (Pcalc − Pexp)/Pexp) between the Ideal Gas Law (Pcalc) and the data of Table 2 and Table 3 (Pexp), respectively. For blends of R1234yf and propane (Table 2 and Figure 3), the mean deviation is ΔP/P = (9.866) % with a mean absolute deviation (|100·ΔP/P|) of (9.866). For blends of R1225ye(Z) and propane (Table 3 and Figure 4), the mean deviation is ΔP/P = (9.362) % with a mean absolute deviation |100·ΔP/P| of (9.362). Note that this model is termed IG. Fundamental Helmholtz Free Energy Equation of State. Figure 5 shows ΔP/P between the default high-accuracy Equations of State (EoS) based on reduced molar Helmholtz free energy for R1234yf18 and propane19 contained in REFPROP20 plus a modified van der Waals one-fluid linear mixing model,21 where the constants Kt = 1.01 and Kv = 0.97 (Pcalc) and the data of Table 2 (Pexp). The mean deviation is ΔP/P = (0.24) % with a mean absolute deviation |100·ΔP/P| of (0.62). Kt and Kv were chosen to minimize the mean absolute error. Note that this model is termed REF2 and referred to as REF if the constants Kt and Kv are both set equal to unity. A further note is that no similar analysis could be conducted for R1225ye(Z) and propane since no high-accuracy EoS based on reduced molar Helmholtz free energy exists for R1225ye(Z). Peng−Robinson and Extended Corresponding Equations of State. Because of the previously mentioned limitation, the authors, similar to what they have done elsewhere,22,23 developed simple Peng−Robinson (P−R) EoS for R1234yf, R1225ye(Z), and propane so that comparisons and predictions also could be made for blends of fluids that do not have well-described EoS, e.g., R1225ye(Z). In addition to the P−R EoS formulation, the authors also have developed simple Extended Corresponding States (ECS) EoS for the same fluids. Note that other similar EoS requiring minimal experimental data for their developments besides P−R and ECS also could be employed. Herein, however, we have elected to illustrate the capability with P−R EoS and ECS EoS because both can be developed with minimal experimental data, are easy to implement with the existing framework of REFPROP,20 and have been shown to provide good engineering accuracies for a wide-range of working fluids.22,23

Figure 8. Deviations (ΔP/P = (Pcalc − Pexp)/Pexp) between P−R EoS (Pcalc) for R1225ye(Z) and propane developed by the authors plus a modified van der Waals one-fluid linear mixing model,21 where the constants Kt = 0.95 and Kv = 0.85 and the data of Table 3 (Pexp): ●, xC3H8 = 0.516 and v = 0.067 m3·kg−1; O, xC3H8 = 0.855 and v = 0.090 m3·kg−1; ■, xC3H8 = 0.255 and v = 0.042 m3·kg−1; △, xC3H8 = 0.593 and v = 0.039 m3·kg−1; ▲, xC3H8 = 0.690 and v = 0.032 m3·kg−1.

Figure 9. Deviations (ΔP/P = (Pcalc − Pexp)/Pexp) between ECS EoS (Pcalc) for R1225ye(Z) and propane developed by the authors plus a modified van der Waals one-fluid linear mixing model,21 where the constants Kt = 0.99 and Kv = 0.74 and the data of Table 3 (Pexp): ●, xC3H8 = 0.516 and v = 0.067 m3·kg−1; O, xC3H8 = 0.855 and v = 0.090 m3·kg−1; ■, xC3H8 = 0.255 and v = 0.042 m3·kg−1; △, xC3H8 = 0.593 and v = 0.039 m3·kg−1; ▲, xC3H8 = 0.690 and v = 0.032 m3·kg−1.

The vapor pressures, liquid densities, and vapor phase PvTx behaviors of the pure components R1234yf and R1225ye(Z) have been previously measured using this apparatus and reported elsewhere.14−17

Table 4. Coefficients for Bblend, Equation 2, and for Cblend, Equation 3 B1

B2

B3

B4

B5

R1234yf + propane R1225ye(Z) + propane

−0.58979 0.37827 C1

−457.797 −117.106 C2

1.16312 1.22419 C3

−0.46850 −1.66494 C4

4.24839 −1.54101 C5


−0.81056 −2.32900

−135.159 −726.508

−0.39441 −6.38597

E

−2.05193 9.31558

6.65362 12.2014



Article

Figure 10. (a) Bblend [eq 2] for binary blends of R1234yf and propane as a function of mole fraction of propane and temperature (each symbol represents one of the 20 measured isotherms which ranged from 268.2 to 363.2 K.). (b) Cblend [eq 3] for binary blends of R1234yf and propane as a function of mole fraction of propane and temperature (each symbol represents one of the 20 measured isotherms which ranged from 268.2 to 363.2 K.). (c) Bblend [eq 2] for binary blends of R1225ye(Z) and propane as a function of mole fraction of propane and temperature (each symbol represents one of the 19 measured isotherms which ranged from 273.1 to 363.2 K.). (d) Cblend [eq 3] for binary blends of R1225ye(Z) and propane as a function of mole fraction of propane and temperature (each symbol represents one of the 19 measured isotherms which ranged from 273.1 to 363.2 K).

Figure 12. Deviations (ΔP/P = (Pcalc − Pexp)/Pexp) between Virial EoS (Pcalc) of eq 1 and the data of Table 3 (Pexp) for binary blends of R1225ye(Z) and propane: ●, xC3H8 = 0.516 and v = 0.067 m3·kg−1; O, xC3H8 = 0.855 and v = 0.090 m3·kg−1; ■, xC3H8 = 0.255 and v = 0.042 m3· kg−1; △, xC3H8 = 0.593 and v = 0.039 m3·kg−1; ▲, xC3H8 = 0.690 and v = 0.032 m3·kg−1.

Figure 11. Deviations (ΔP/P = (Pcalc − Pexp)/Pexp) between Virial EoS (Pcalc) of eq 1 and the data of Table 2 (Pexp) for binary blends of R1234yf and propane: ●, xC3H8 = 0.709 and v = 0.095 m3·kg−1; O, xC3H8 = 0.505 and v = 0.072 m3·kg−1; ■, xC3H8 = 0.230 and v = 0.049 m3·kg−1; △, xC3H8 = 0.611 and v = 0.047 m3·kg−1; ▲, xC3H8 = 0.839 and v = 0.047 m3·kg−1.

Figure 6 and Figure 7 show ΔP/P between a P−R EoS and an ECS EoS, respectively, for both R1234yf and propane as developed by the authors coupled with a modified van der Waals

one-fluid linear mixing model21 (Pcalc) and the data of Table 2 (Pexp). The constants Kt and Kv are (1.01 and 0.95), respectively, F



Article

Table 5. Percentage of Measured Data Within Specified Bounds for Binary Blends of R1234yf and Propane model bounds

IG

PR

PR2

ECS

ECS2

ref

ref2

virial

±0.025% ±0.05% ±0.25% ±0.50% ±1.00% ±1.50% ±2.50%

0.0 0.0 0.0 0.0 0.0 0.0 0.0

0.0 0.0 7.1 47.6 63.1 100.0 100.0

0.0 1.2 17.9 44.0 66.7 100.0 100.0

2.4 4.8 15.5 34.5 70.2 91.7 100.0

4.8 9.5 41.7 59.5 60.7 76.2 100.0

3.6 4.8 31.0 48.8 75.0 96.4 100.0

3.6 6.0 28.6 51.2 76.2 95.2 100.0

32.1 53.6 96.6 97.6 100.0 100.0 100.0

Table 6. Percentage of Measured Data Within Specified Bounds for Binary Blends of R1225ye(Z) and Propane model bounds

IG

PR

PR2

ECS

ECS2

±0.025% ±0.05% ±0.25% ±0.50% ±1.00% ±1.50% ±2.50%

0.0 0.0 0.0 0.0 0.0 0.0 0.0

0.0 0.0 0.0 0.0 17.4 40.6 100.0

4.3 11.6 39.1 49.2 78.3 100.0 100.0

0.0 0.0 0.0 0.0 11.6 44.9 92.8

2.9 5.8 26.1 46.4 82.6 92.8 100.0

⎞ B blend C RT ⎛ ⎜1 + ⎟ + blend 2 ⎠ ⎝ v v v

ref2

virial 20.3 43.5 92.8 100.0 100.0 100.0 100.0

Cblend were assumed to have a functional form in T and x as given by eq 2 and eq 3, respectively

for the P−R EoS and are (1.01 and 0.87), respectively, for the ECS EoS. The former model is termed PR2 and the latter one is termed ECS2. Note that if the constants Kt and Kv are set to unity, the models are termed PR and ECS, respectively. Similarly, Figure 8 and Figure 9 show ΔP/P between a P−R EoS and an ECS EoS, respectively, for both R1225ye(Z) and propane as developed by the authors coupled with a modified van der Waals one-fluid linear mixing model21 (Pcalc) and the data of Table 3 (Pexp). The constants Kt and Kv are (0.95 and 0.85), respectively, for the P−R EoS and are (0.99 and 0.74), respectively, for the ECS EoS. The former model is termed PR2 and the latter one is termed ECS2. Note that if the constants Kt and Kv are set to unity, the models are termed PR and ECS, respectively. As shown in Figure 6 for blends of R1234yf and propane, the mean deviation between the P−R EoS model PR2 (Pcalc) and the data of Table 2 (Pexp) is ΔP/P = (0.101) % with a mean absolute deviation (|100·ΔP/P|) of (0.662). As shown in Figure 7 for blends of the same fluids, the mean deviation between the ECS EoS model ECS2 (Pcalc) and the data of Table 2 (Pexp) is ΔP/P = (0.633) % with a mean absolute deviation (|100·ΔP/P|) of (0.725). As shown in Figure 8 for blends of R1225ye(Z) and propane, the mean deviation between the P−R EoS model PR2 (Pcalc) and the data of Table 3 (Pexp) is ΔP/P = (−0.357) % with a mean absolute deviation (|100·ΔP/P|) of (0.540). As shown in Figure 9 for blends of the same fluids, the mean deviation between the ECS EoS model ECS2 (Pcalc) and the data of Table 2 (Pexp) is ΔP/P = (−0.383) % with a mean absolute deviation (|100·ΔP/P|) of (0.620). Virial Equation of State. In this section, we fit the data of Table 2 and Table 3 to a Virial EoS with the aim to reduce the deviations between the model and the experimental data. Here, we adopt the truncated Virial EoS provided in eq 1 P=

ref

B blend = B1ln T +

B2 + B3xC23H8 + B4 xC3H8 + B5 T

(2)

C blend = C1ln T +

C2 + C3xC23H8 + C4xC3H8 + C5 T

(3)

−1

where T is in K and x is in kmol·kmol . The constants B1... B5 and C1... C5 were determined by minimizing the mean absolute deviations between eq 1 and the data of Table 2 and Table 3. The resulting coefficients of eq 2 and eq 3 are provided in Table 4. In addition, Figure 10 illustrates graphically the values of Bblend [eq 2] and Cblend [eq 3] for blends of R1234yf and propane (Figure 10a and Figure 10b) and for blends of R1225ye(Z) and propane (Figure 10c and Figure 10d). As shown in Figure 11 for blends of R1234yf and propane, the mean deviation between the Virial EoS (Pcalc) and the data of Table 2 (Pexp) is ΔP/P = (0.006) % with a mean absolute deviation (|100·ΔP/P|) of (0.078). As shown in Figure 12 for blends of R1225ye(Z) and propane, the mean deviation between the Virial EoS (Pcalc) and the data of Table 3 (Pexp) is ΔP/P = (−0.002) % with a mean absolute deviation (|100·ΔP/P|) of (0.086). Summary of Model Results. Table 5 and Table 6 present summary results for the eight models employed to fit the data. Table 5 shows percentages of measured data falling within specified bounds for blends of R1234yf and propane and Table 6 shows similar results for blends of R1225ye(Z) and propane. The models PR2, ECS2, REF2, that is, ones where the linear mixing model constants Kt and Kv were chosen to minimize the mean absolute error, and the Virial EoS perform the best among the models. For example, for blends of R1234yf and propane, 66.7%, 60.7%, 76.2%, and 100.0% of the measured data have deviations within ±1% for the PR2, ECS2, REF2, and Virial models. Similarly for blends of R1225ye(Z) and propane, 78.3%, 82.6%, and 100.0% of the measured data have deviations within ±1% for the PR2, ECS2, and Virial models. In summary, the Ideal Gas EoS does not predict well any of the data and the Virial EoS

(1)

where P is in kPa, R is in kJ·kmol−1·K−1, v is in m3·kmol−1, Bblend is in m3·kmol−1, and Cblend is in m6·kmol−2. The constants Bblend and G



Article

Table 7. Average Absolute Relative Percentage Deviations Between Models and the Measured Data for Blends of R1234yf and Propane and for Blends of R1225ye(Z) and Propane model blend

IG

PR

PR2

ECS

ECS2

ref

ref2

virial


9.866 9.362

0.663 1.388

0.662 0.540

0.773 1.644

0.725 0.620

0.613

0.617

0.078 0.086

Change and the joint fulfilment of commitments thereunder. Off. J. Eur. Union: Legis. 2002, 130, 1−20. (3) Regulation (EC) No 842/2006 of The European Parliament and of the Council of 17 May 2006 on Certain Fluorinated Greenhouse Gases. Off. J. Eur. Union: Legis. 2006, 161, 1−11. (4) Directive 2006/40/EC of The European Parliament and of the Council of 17 May 2006 Relating to Emissions from Air-Conditioning Systems in Motor Vehicles & Amending Council Directive 70/156/EC. Off. J. Eur. Union: Legis. 2006, 161, 12−18. (5) Regulation (EU) No 517/2014 of the European Parliament and of the Council of 16 April 2014 on fluorinated greenhouse gases and repealing Regulation (EC) No 842/2006 Text with EEA relevance. Off. J. Eur. Union: Legis. 2014, 150, 195−230. (6) Recent International Developments Under the Montreal Protocol. U.S. Environmental Protection Agency. https://www.epa.gov/ozonelayer-protection/recent-international-developments-under-montrealprotocol (accessed May 13, 2016). (7) Di Nicola, G.; Di Nicola, C.; Arteconi, A.; Stryjek, R. PVTx measurements of the carbon dioxide + 2,3,3,3-Tetrafluoroprop-1-ene binary system. J. Chem. Eng. Data 2012, 57, 450−455. (8) Di Nicola, G.; Passerini, G.; Polonara, F.; Stryjek, R. PVTx measurements of the carbon dioxide + trans-1,3,3,3-Tetrafluoroprop-1ene binary system. Fluid Phase Equilib. 2013, 360, 124−128. (9) Brown, J. S.; Corvaro, F.; Di Nicola, G.; Giuliani, G.; Pacetti, M. PVT measurements of trans-1,3,3,3-tetrafluoroprop-1-end + methane and trans-1,3,3,3-tetrafluoroprop-1-end + nitrogen binary pairs. J. Chem. Eng. Data 2014, 59, 3798−3804. (10) McLinden, M. O.; Kazakov, A. F.; Brown, J. S.; Domanski, P. A. A thermodynamic analysis of refrigerants: Possibilities and tradeoffs for low-GWP refrigerants. Int. J. Refrig. 2014, 38, 80−92. (11) Giuliani, G.; Kumar, S.; Polonara, F. A constant volume apparatus for vapour pressure and gas phase P-v-T measurements: Validation with data for R22 and R134a. Fluid Phase Equilib. 1995, 109, 265−279. (12) Di Nicola, G.; Polonara; Ricci, R.; Stryjek, R. PVTx measurements for the R116 + CO2 and R41 + CO2 systems. New isochoric apparatus. J. Chem. Eng. Data 2005, 50, 312−318. (13) Hurly, J. J.; Schmidt, J. W.; Boyes, S. J.; Moldover, M. R. Virial equation of state of helium, xenon, and helium-xenon mixtures from speed-of-sound and burnett. Int. J. Thermophys. 1997, 18, 579−634. (14) Di Nicola, G.; Polonara, F.; Santori, G. Saturated pressure measurements of 2,3,3,3-tetrafluoroprop-1-ene (HFO-1234yf). J. Chem. Eng. Data 2010, 55, 201−204. (15) Di Nicola, C.; Di Nicola, G.; Pacetti, M.; Polonara, F.; Santori, G. P-V-T behavior of 2,3,3,3-tetrafluoroprop-1-ene (HFO-1234yf) in the vapor phase from (243 to 373) K. J. Chem. Eng. Data 2010, 55, 3302− 3306. (16) Fedele, L.; Di Nicola, G.; Brown, J. S.; Colla, L.; Bobbo, S. Saturated pressure measurements of cis-1,2,3,3,3-pentafluoroprop-1ene (R1225ye(Z). Int. J. Refrig. 2016, 69, 243−250. (17) Brown, J. S.; Fedele, L.; Di Nicola, G.; Bobbo, S.; Coccia, G. Compressed liquid density and vapor phase PvT measurements of cis1,2,3,3,3-pentafluoroprop-1-ene (R1225ye(Z). J. Chem. Eng. Data 2015, 60, 3333−3340. (18) Richter, M.; McLinden, M. O.; Lemmon, E. W. Thermodynamic properties of 2,3,3,3-tetrafluoroprop-1-ene (R1234yf): Vapor pressure and p-ρ-T measurements and an equation of state. J. Chem. Eng. Data 2011, 56, 3254−3264. (19) Lemmon, E. W.; McLinden, M. O.; Wagner, W. Thermodynamic properties of propane. III. A reference equation of state for temperatures

performs considerably better than the other three highperforming models, though each of them performs quite adequately for engineering purposes. Finally, Table 7 summarizes the average absolute relative percentage deviations for each of the models for blends of R1234yf and propane and for blends of R1225ye(Z) and propane.

■

CONCLUSIONS There is considerable interest in low-GWP working fluids for refrigeration, air conditioning, and power producing applications. Unfortunately, as more and more constraints, including environmental ones, are placed on working fluids, it becomes increasingly more difficult to identify “ideal” single-component working fluids able to meet both design constraints and application needs. Thus, blends of working fluids are being investigated as they afford possibilities to tailor a working fluid’s characteristics, for example, thermophysical properties, GWP, and safety, above what is possible with single-component working fluids. Therefore, this paper wishes to contribute to this effort by presenting vapor phase PvTx measurements for two binary blends of low-GWP working fluids. The binary blends consist of a hydrocarbon (propane) and one of two unsaturated halocarbon working fluids, both of which have seen considerable research and development efforts over the last 15 or so years. Propane was chosen as one of the blend componentsdespite its flammabilitybecause it is able to increase lubricant solubility and improve heat exchanger performance, both of which lead to improved overall system performance. Because there is considerable work still to be accomplished in identifying and characterizing appropriate low-GWP blends of working fluids for a wide-variety of applications, the authors intend to continue these research efforts and would encourage others to do so as well.

■

AUTHOR INFORMATION

Corresponding Author

*Tel. + 39 071 2204277. Fax +39 071 2202324. E-mail: [email protected]. Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS The authors thank Arkema France for donating the R1234yf sample and Mexichem Fluor S.A. de C.V. for donating the R1225ye(Z) sample.

■

REFERENCES

(1) Kyoto Protocol. United Nations Framework Convention on Climate Change. unfccc.int/kyoto_protocol/items/2830.php (accessed May 13, 2016). (2) No 2002/358/EC: Council Decision of 25 April 2002 concerning the approval, on behalf of the European Community, of the Kyoto Protocol to the United Nations Framework Convention on Climate H



Article

from the melting line to 650 K and pressures up to 1000 MPa. J. Chem. Eng. Data 2009, 54, 3141−3180. (20) Lemmon, E. W.; Huber, M. L.; McLinden, M. O. NIST Standard Reference Database 23, Reference Fluid Thermodynamic and Transport Properties (REFPROP), version 9.1; National Institute of Standards and Technology: Gaithersburg, MD, 2010; R1234yf.fld and propane.fld files updated December 6, 2012. (21) McLinden, M. O.; Klein, S. A. A Next Generation Refrigerant Properties Database. Proceedings of the 1996 International Refrigeration and Air Conditioning Conference; Purdue University: West Lafayette, IN, 1996; pp 409−414. (22) Brown, J. S. Predicting performance of refrigerants using the Peng-Robinson equation of state. Int. J. Refrig. 2007, 30, 1319−1328. (23) Brown, J. S.; Zilio, C.; Cavallini, A. Thermodynamic properties of eight fluorinated olefins. Int. J. Refrig. 2010, 33, 235−241.

I


Vapor Phase PvTx Measurements of Binary Blends of 2,3,3,3

Recommend Documents