Investigation on the VaporâLiquid Equilibrium for the Ternary Mixture

Article pubs.acs.org/jced

Investigation on the Vapor−Liquid Equilibrium for the Ternary Mixture HFC-32 + HFC-125 + HFC-161 at Temperatures from 265.15 K to 303.15 K Xuehui Wang,†,‡ Zanjun Gao,‡ Xu Gao,† Wenjie Guan,‡ Xiaohong Han,*,‡ and Guangming Chen‡ †

The State Key Laboratory of Technologies in Space Cryogenic Propellants, Beijing 100028, P. R. China Institute of Refrigeration and Cryogenics, Key Laboratory of Refrigeration and Cryogenic Technology of Zhejiang Province, Zhejiang University, Hangzhou 310027, P. R. China

Downloaded by STOCKHOLM UNIV on August 25, 2015 | http://pubs.acs.org Publication Date (Web): August 24, 2015 | doi: 10.1021/acs.jced.5b00405

‡

ABSTRACT: The ternary mixture HFC-32 + HFC-125 + HFC-161 was considered as a potential alternative refrigerant to HCFC-22 and HFC-410A for the environmentally friendly and excellent thermodynamic properties. Vapor−liquid equilibrium data are necessary for the mixed refrigerant to evaluate its optimal composition and the cycle performance in the refrigeration cycles. On the basis of this, the vapor−liquid equilibrium data for the mixture HFC-32 + HFC-125 + HFC161 were investigated by the experiment. The vapor−liquid equilibrium data were correlated with the Peng−Robinson (PR) equation-of-state combined with the LCVM (linear combination of Vidal and Michelsen) mixing rule and the NRTL (nonrandom two liquid) excess free energy model. The correlated results revealed a good agreement with the experimental data. The average value of the absolute relative pressure deviations was 0.9 %, and the average values of the absolute composition deviations (abs (y1 − y1,cal), abs(y2 − y2,cal)) were 0.0098 and 0.0105, respectively. The results further suggested that there was no azeotrope for the ternary mixture. In addition, on the basis of the interactive parameters obtained by correlating the ternary mixture, the predictions for the binary mixtures HFC-32 + HFC-161, HFC-32 + HFC-125 and HFC-161 + HFC-125 at temperatures of 283.15 K, 293.15 K were conducted. The predicted results were analyzed and discussed by comparison with experimental data from the literature.

■. INTRODUCTION It is well known that refrigeration technology gives the technical aids to air-conditioning systems, industrial processes, cool chain including production, transportation, sale and storage at the consumer’s home in a refrigerator, and so forth. The progresses of refrigeration technologies may contribute to human comfort and meet the requirements of different occasions, but they also can threaten the environment by the emission of the refrigerants (with the effect of ozone depletion and global warming) used in the refrigeration system. Therefore, in recent decades, the refrigerant industry has undergone significant transformation to systematically phaseout the harmful ozone-depleting refrigerants (known as CFC’s and HCFC’s).1 At present, it is extremely urgent to find the promising replacement of these refrigerants. It is more urgent to find the promising alternative refrigerants of HCFC-22. Natural refrigerants, such as ammonia,2 hydrocarbons,3,4 carbon dioxide,5 and so forth, provide alternatives to HCFC-22 in different working conditionings. For example, hydrocarbons are the preferred refrigerants in many European countries.6 The natural refrigerants have zero ozone depletion potential (ODP) and low or no global warming potential (GWP), and they are compatible with common elastomer materials used in refrigeration systems and are soluble in the conventional mineral oils. Meanwhile, the natural refrigerants do not contain chlorine or fluorine atoms, it is impossible for them to form the © XXXX American Chemical Society

corresponding strong acids when contact with water which can lead to premature system failure. However, until now, their application has some limitations for their disadvantages like the toxicity of ammonia, strong flammability of hydrocarbon, and the high operating pressure of carbon dioxide system.7 Hydrofluorocarbons (HFCs) have been considered as the potential alternatives of HCFC-22. For example, it is well known that HFC-407C and HFC-410A are the dominant alternatives,8,9 though the systems need to be redesigned to meet the requirement of high operating pressure of HFC-410A when HFC-410A was used in the refrigeration system.10 The performances of HFC-404A and HFC-507 as alternatives to HCFC-22 in a window air-conditioner were analyzed by Bolaji.11 However, increasing concerns about global warming has emphasized the need for refrigerants with low global warming potential (GWP).12 Therefore, it is quite possible for HFC-407C and HFC-410A to be phased out in the future for their high GWPs (GWPHFC‑407C = 1700, GWPHFC‑410A = 2000).13 Thus, research on their alternatives with good environmental acceptability, remarkable thermophysical properties, as well as safety have been conducted. At present, HFC32 was proposed to be a potential replacement of HFC-410A Received: May 10, 2015 Accepted: August 14, 2015

A

DOI: 10.1021/acs.jced.5b00405 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article


Table 1. Description of the Materials Used refrigerant

chemical name

source

initial mass fraction purity

purification method

CAS registry no.

HFC-32 HFC-125 HFC-161

difluoromethane pentafluoroethane ethyl fluoride

FLTCO

> 99.98 % > 99.98 % > 99.70 %

none none none

75-10-5 354-33-6 353-36-6

temperature−liquid and vapor composition p−T−x−y data are obtained from the experimental apparatus based on a circulated-analytic method. It consists of the stainless steel equilibrium cell, the thermostatic bath, the temperature and pressure measuring systems and the other parts. Approximately 18 L glass thermostatic bath insulated with polyurethane foams has been constructed, which is equipped with double glass windows. The stainless steel equilibrium cell has a volume of 80 mL, and equipped with two glass windows of 12 mm thickness. During the experiment, the glass windows for the thermostatic bath and equilibrium cell were placed in the same height, thus, the mixed refrigerant in the equilibrium cell can be observed by the windows. A liquid circulation loop was equipped for promoting the equilibration and also for sampling of liquid phase. The liquid outlet from cell penetrates the wall of the cell and connects to the vapor. The vapor outlet from cell penetrates the cover of the thermostatic bath and then connects to the vapor pump. The pump head and the parts outside the thermostatic bath are wrapped with heating tapes and well insulated. The thermostatic bath temperature is measured by a platinum resistance thermometer (model: WZPI, Kunming Temperature Instrument Co., Ltd., China) with a precision of 0.001 K. The pressure inside the cell is measured by pressure transducer (model: PMP4010, Druck, England) with an accuracy of 0.04 % FS (full scale (FS) pressure is 3.5 MPa). Temperatures and pressures are logged by a Keithley 2002 data acquisition/switch unit. After the uncertainties from the platinum resistance thermometer, the pressure transducer and the digital multimeter are considered, the whole standard temperature uncertainty and pressure uncertainty for the system are less than 11 mK and 1.4 kPa, respectively. The liquid sample is collected via the sampling port, and the vapor sample is taken online by a six-port sampling valve with 15 μL sampling loop. Both vapor and liquid samples are analyzed by gas chromatograph (GC) equipped with a Flame Ionization Detector (FID) (model: GC112A, INESA Instrument, China). The experimental procedures were as follows. The system was first evacuated to remove the internal gases. A targeted amount of HFC-32, HFC-125, and HFC-161 was charged into cell and the experimental temperature of the entire system was maintained by controlling the temperature of the thermostatic bath. The vapor in the cell was circulated continuously by the magnetic circulation pump until an equilibrium state was established. When the temperature fluctuation was less than 5 mK/30 min, the pressure fluctuation was within 300 Pa/30 min, it was believed that the thermal equilibrium state was achieved between the cell fluid and the thermostatic bath. After the desired temperature was obtained, the average pressure and temperature in the equilibrium cell were recorded, respectively. The compositions of the samples were measured by immediately injecting them into the GC which was connected online to vapor−liquid sampling valves. The GC was calibrated with pure components of known purity and with mixtures of known composition that were prepared gravimetrically. The experimental data at the equilibrium state were measured at least three times in order to ensure repeatability. Considering

for its good thermophysical properties and the similar high system pressure with HFC-410A.10 To compensate the high operating pressure of HFC-32 refrigeration system, the mixture of HFC-32 and HFO-1234yf was proposed to replace the HCFC-22.12 HFC-161, as a refrigerant with good environmental acceptability (GWP = 12, ODP = 0), good thermophysical properties14−17 and highly similar thermophysical properties to HCFC-22 and HFC-407C, has attracted broad attention for the direct substitute of HFC-407C. However, the major limitation of HFC-161 is its potential flammability. Thus, the mixture of HFC-32 + HFC-125 + HFC-16114,18 was proposed as the promising replacement of HFC-407C and HCFC-22. For the mixed refrigerant, the vapor−liquid equilibrium data are required as one of the most important information in evaluating the performance of refrigeration cycles and determining their optimal compositions. Therefore, the vapor−liquid equilibrium data for the ternary mixture HFC-32 + HFC-125 + HFC-161 are measured in this paper, and the experimental data are correlated with the Peng−Robinson (PR) equation-of-state19 combined with the linear combination of Vidal and Michelsen (LCVM) mixing rule20 and the nonrandom two liquid (NRTL)21 excess free energy model. In addition, on the basis of the interactive parameters obtained by correlating the ternary mixture, the prediction for the binary mixtures HFC-32 + HFC-161, HFC-32 + HFC-125 and HFC-125 + HFC-161 at the temperatures of 283.15 K, 293.15 K is further discussed.

■. EXPERIMENT Materials. HFC-32, HFC-125, and HFC-161 are supplied by Zhejiang Lantian Environmental Protection Co., Ltd. (FLTCO) with a minimum purity of 99.98 %, 99.98 %, and 99.70 %, respectively. The basic description of the materials used is shown in Table 1. All samples were used without any further purification. Experimental Equipment and Procedures. The experimental apparatus used in this work for measuring the vapor− liquid equilibrium data of the mixed refrigerant is shown in Figure 1, which is the same as the literature.22,23 Pressure−

Figure 1. Schematic diagram of the VLE apparatus. B



Article


Table 2. Experimental and Calculated Results for Temperature T, Pressure p, Liquid-Phase Mole Fraction x, and Vapor-Phase Mole Fraction y by PR + LCVM + NRTL Model for the Mixture (HFC-32 (1) + HFC-125 (2) + HFC-161 (3))

a

Ta

pa

pcal

K

kPa

kPa

265.15 265.15 265.15 265.15 265.15 265.15 275.15 275.15 275.15 275.15 275.15 275.15 283.15 283.15 283.15 283.15 283.15 283.15 293.15 293.15 293.15 293.15 293.15 293.15 303.15 303.15 303.15 303.15 303.15 303.15

475 496 546 558 573 590 687 700 766 770 817 826 876 932 984 998 1013 1027 1161 1239 1306 1339 1360 1378 1686 1699 1715 1764 1776 1798

483 504 534 546 562 587 689 701 758 766 808 822 851 935 979 1000 1014 1023 1142 1220 1304 1332 1351 1371 1652 1693 1732 1780 1784 1805

100((p − pcal)/p)

x1a

x2a

y1a

y2a

y1,cal

y2,cal

y1-y1,cal

y2-y2,cal

−1.5 −1.6 2.0 2.0 1.9 0.6 −0.3 −0.2 1.1 0.4 1.1 0.5 2.8 −0.3 0.5 −0.2 0.0 0.3 1.6 1.5 0.2 0.5 0.7 0.5 2.0 0.3 −1.0 −0.9 −0.5 −0.4

0.2035 0.2603 0.3866 0.4300 0.5011 0.6158 0.2622 0.2856 0.3842 0.4266 0.5991 0.6522 0.2447 0.3325 0.4511 0.4951 0.5227 0.5609 0.2167 0.2636 0.3649 0.4207 0.4628 0.5142 0.2329 0.2744 0.3412 0.4412 0.4509 0.4925

0.5329 0.5403 0.4655 0.4402 0.3846 0.2914 0.4435 0.445 0.4701 0.4304 0.3060 0.2774 0.4438 0.5165 0.4335 0.4205 0.4141 0.3788 0.4531 0.5193 0.4972 0.4566 0.4245 0.384 0.4271 0.5162 0.5072 0.4395 0.4346 0.3903

0.2291 0.272 0.4432 0.4947 0.5752 0.6819 0.3463 0.3671 0.4509 0.514 0.6771 0.7068 0.3393 0.4086 0.5232 0.5804 0.6049 0.6349 0.3107 0.3518 0.4306 0.4813 0.5215 0.5611 0.3053 0.339 0.4065 0.4795 0.4993 0.5291

0.5773 0.5696 0.4496 0.4162 0.3542 0.2568 0.4515 0.4569 0.4445 0.4008 0.2679 0.2323 0.4405 0.4916 0.4070 0.3624 0.3631 0.3393 0.446 0.5042 0.449 0.4159 0.3825 0.3579 0.4094 0.4769 0.4691 0.4068 0.3911 0.3677

0.2365 0.3065 0.4547 0.5022 0.5775 0.6903 0.3476 0.3712 0.4579 0.5002 0.6548 0.6976 0.3420 0.4104 0.5233 0.5585 0.5794 0.6147 0.2980 0.3384 0.4328 0.4853 0.5239 0.5702 0.3003 0.3277 0.3909 0.4867 0.4957 0.5360

0.5821 0.5674 0.4638 0.4299 0.3667 0.2693 0.4483 0.4449 0.4494 0.4090 0.2858 0.2585 0.4389 0.4936 0.4032 0.3885 0.3811 0.3471 0.4596 0.5104 0.4745 0.4325 0.4007 0.3615 0.4117 0.4867 0.4709 0.4009 0.396 0.3525

−0.0074 −0.0345 −0.0115 −0.0075 −0.0023 −0.0084 −0.0013 −0.0041 −0.0070 0.0138 0.0223 0.0092 −0.0027 −0.0018 −0.0001 0.0219 0.0255 0.0202 0.0127 0.0134 −0.0022 −0.0040 −0.0024 −0.0091 0.0050 0.0113 0.0156 −0.0072 0.0036 −0.0069

−0.0048 0.0022 −0.0142 −0.0137 −0.0125 −0.0125 0.0032 0.0120 −0.0049 −0.0082 −0.0179 −0.0262 0.0016 −0.0020 0.0038 −0.0261 −0.0180 −0.0078 −0.0136 −0.0062 −0.0255 −0.0166 −0.0182 −0.0036 −0.0023 −0.0098 −0.0018 0.0059 −0.0049 0.0152

Standard uncertainties u are u(T) = 0.01 K, u(p) = 1.4 kPa, u(x1) = 0.003, u(x1) = 0.003, u(y1) = 0.003, u(y2) = 0.003.

the margin of error and reproducibility of GC, it was generally estimated an overall uncertainty in the measurements of the composition of ± 0.003 in mole fraction for both the liquid and vapor phases. Experimental Data. Following the experimental procedure described previously, the pressure−temperature−liquid and vapor composition (p−T−x−y) measurements are made for the ternary mixture HFC-32 + HFC-125 + HFC-161 at temperature between 265.15 K and 303.15 K. The measured temperature, pressure, and mole fractions data for the system HFC-32 + HFC-125 + HFC-161 are listed in Table 2.

α = (1 + (0.37464 + 1.54226ω − 0.26992ω 2) 2

(1 − (T /Tc)0.5 )) b = 0.07780RTc/pc

PR equation-of-state19 combined with the LCVM mixing rule22 was correlated for VLE data of the mixture (HFC-32 + HFC125 + HFC-161), in which the NRTL23 activity coefficient model was used to calculate the excess Gibbs free energy. PR equation-of-state19 was expressed as RT a − 2 v−b v + 2vb − b2

a = 0.45724R2Tc 2/pc α(T )

(4)

where p is the pressure; v is the molar volume; T is the absolute temperature; pc is the critical pressure; Tc is the critical temperature; ω is the acentric factor; R is the general gas constant; and a and b are equation-of-state dependent parameters. LCVM mixing rule20 was obtained by linearly combining the α(a/(bRT) term of the zero reference pressure MHV1 model and the infinite reference pressure Huron−Vidal model. Though there is no basis in theory, this model provides reasonable results for highly asymmetric mixtures empirically. Therefore, the model was widely used in the prediction of vapor−liquid equilibrium data. Its expression is as follows:

■. RESULTS AND DISSCUSSION

p=

(3)

E ⎛ λ am 1−λ⎞g 1−λ =⎜ + + ⎟ bmRT C C RT C ⎝ HV MHV1 ⎠ MHV1 ai + ∑ xi biRT i

(1)

bm =

(2)

∑ xibi i

C

⎛ bm ⎞ ⎟ ⎝ bi ⎠

∑ xi ln⎜ i

(5)

(6) DOI: 10.1021/acs.jced.5b00405 J. Chem. Eng. Data XXXX, XXX, XXX−XXX


Article

Table 3. Critical Parameters and Acentric Factors13 compound

formula

HFC-32 HFC-125 HFC-161

CH2F2 C2HF5 CH3CH2F

MW

Tc

pc

Vc

g/mol

K

MPa

cm3/mol

52.02 120.03 48.06

351.60 339.20 375.30

5.83 3.59 5.02

122.688 210.099 169.00

Zc

ω

0.242 0.270 0.261

0.271 0.303 0.215

where g is Gibbs free energy and λ = 0.36, CHV = −0.623, CMHV1 = −0.52 for PR equation-of-state, superscript E, subscripts HV and MHV1, are excess property, Huron−Vidal mixing rule, the first modified Huron−Vidal mixing rule, respectively. x stands for liquid mole fraction, subscript i is the ith component. The excess Gibbs energy is calculated using the NRTL local composition model21 g(ET , P) Downloaded by STOCKHOLM UNIV on August 25, 2015 | http://pubs.acs.org Publication Date (Web): August 24, 2015 | doi: 10.1021/acs.jced.5b00405

RT

ln γi =

=

∑ xi ∑ i

j

xjexp( −αj , iτj , i) ∑k xk exp( −αk , iτk , i)

∑j τj , i exp( −αj , iτj , i)xj ∑k xk exp( −αk , iτk , i)

⎡

+

∑⎢ j

τj , i (7)

Figure 3. Relative deviations of vapor pressure for the ternary mixture (HFC-32 (1) + HFC-125 (2) + HFC-161 (3)).

xjexp( −αi , jτi , j)

⎢⎣ ∑k xk exp( −αk , jτk , j)

⎛ ∑ x τ exp( −αk , jτk , j) ⎞⎤ ⎜⎜τi , j − k k k , j ⎟⎥ ∑k xk exp( −αk , jτk , j) ⎟⎠⎥⎦ ⎝

2 and Figures 2 and 3, it can be seen that the correlated results obtained by PR + LCVM + NRTL model for the ternary mixture (HFC-32 + HFC-125 + HFC-161) have a good agreement with existing experimental data within the specific temperature and pressure ranges, and the average value of the absolute relative pressure deviations is 0.9 %, the average value of the absolute composition deviations (abs (y1 − y1,cal)) is 0.0098, the average value of the absolute composition deviations (abs(y2 − y2,cal)) is 0.0105; the absolute largest absolute deviations of the vapor composition is 0.0345, and the absolute value of largest relative pressure deviation is 2.75 %. The deviation results were further summed up in Table 4. Meanwhile, the results for the interactive parameters τ12, τ13, τ21, τ23, τ31, τ32 of NRTL model obtained by the correlation were also shown in Table 5.

(8)

where τi,i = 0 and αi,i = 0. αj,i, τj,i, and τi,j are adjustable parameters. For the system in this paper, it is recommended to use αj,i = 0.3. τj,i and τi,j are adjusted directly to VLE data through a following algorithm using the objective function ⎛ p − p ⎞2 exp cal ⎟ 2 OF = ∑ ⎜⎜ ⎟ + (y1,exp − y1,cal )i p i=1 ⎝ ⎠i exp Np

+ (y2,exp − y2,cal )i2

(9)

where Np stands for the number of the experimental data, y stands for the vapor mole fraction, and subscripts exp and cal are experimental results and calculated results, respectively. During the correlation process, the basic properties used were shown in Table 3. The correlated results obtained by PR + LCVM + NRTL model are shown in Table 2, and the absolute deviations of vapor mole fraction and relative deviations of system pressure for the ternary mixture (HFC-32 + HFC-125 + HFC-161) are given in Figures 2 and 3, respectively. From the results in Table

Table 4. Deviation Results of Vapor−Liquid Equilibrium Using the PR + LCVM + NRTL Model for (HFC-32 (1) + HFC-125 (2) + HFC-161 (3)) from T = (265.15 to 303.15) K T (K)a

δpb

Δy1c

Δy2d

max δp

max Δy1

max Δy2

1.64 059 0.68 0.69 0.86

0.0119 0.0096 0.0120 0.0073 0.0083

0.0100 0.0121 0.0099 0.0140 0.0066

2.04 1.09 2.75 1.04 2.02

0.0345 0.0223 0.0255 0.0134 0.0156

0.0142 0.0262 0.0197 0.0195 0.0155

K 265.15 275.15 283.15 293.15 303.15

Standard uncertainties u are u(T) = 0.01 K. bδp is relative pressure N average deviation, and it is defined as δp = (1/Np)∑i =p 1|(p − pcal)/p|. c Δy1 is the average deviation of the component 1 and it is defined as N Δy1 = (1/Np)∑i =p 1|y1 − y1,cal|. dΔy2 is the average deviation of the component 2 and it is defined as Δy2 = (1/Np)∑i N=p 1|y2 − y2,cal|. a

Figures 4−6 revealed the vapor−liquid equilibrium phase behavior of the ternary mixture HFC-32 (1) + HFC-125 (2) + HFC-161(3) at 275.15 K, 283.15 K, and 293.15 K (Need to explain: the phase behavior of the ternary mixture HFC-32 (1) + HFC-125 (2) + HFC-161(3) at 265.15 K, 303.15 K is similar, here, the figures will not be given repeatedly). From Figures 4−6, the results suggested that there was no azeotrope in the

Figure 2. Absolute deviations of vapor mole fraction for the ternary mixture (HFC-32 (1) + HFC-125 (2) + HFC-161 (3)). D



Article

Table 5. Correlated Results of Vapor-Liquid Equilibrium Using the PR + LCVM + NRTL Model for (HFC-32 (1) + HFC-125 (2) + HFC-161 (3)) from T = (265.15 to 303.15) K T

τ12

τ13

τ21

τ23

τ31

τ32

α

16.3915 0.4093 0.1057 0.1322 0.0604

−1.2515 0.1036 −0.0466 0.1057 0.6176

0.0288 −0.1653 0.0389 0.0389 0.0387

0.4402 0.1799 −0.0025 −0.0748 0.0800

1.8343 0.0574 0.3261 0.1276 0.3556

−0.2596 −0.3194 −0.3678 −0.1123 0.2343

0.3 0.3 0.3 0.3 0.3

K 265.15 275.15 283.15 293.15 303.15


ternary mixture of HFC-32 (1) + HFC-125 (2) + HFC-161 (3). In addition, on the basis of the interactive parameters obtained by correlating the ternary mixture, the predictions for the binary mixtures HFC-32 + HFC-161, HFC-32 + HFC-125, HFC-125 + HFC-161 at the temperatures of 283.15 and 293.15 K were conducted. The results were shown in Figures 7−9. The

Figure 4. VLE of (HFC-32 (1) + HFC-125 (2) + HFC-161 (3)) with PR + LCVM + NRTL model at 275.15 K. Solid line and dashed line were predicted by PR + LCVM + NRTL model.

Figure 7. VLE data of HFC-32(1) + HFC-125 (2) at 283.15, 293.15 K. Experimental data are from literature.24 Solid lines were predicted by PR + LCVM + NRTL model.

Figure 5. VLE of (HFC-32 (1) + HFC-125 (2) + HFC-161 (3)) with PR + LCVM + NRTL model at 283.15 K. Solid line and dashed line were predicted by PR + LCVM + NRTL model.

Figure 8. VLE data of HFC-32 (1) + HFC-161 (2) at 283.15, 293.15 K. Experimental data are from literature.24 Solid lines were predicted by PR + LCVM + NRTL model.

predicted values were compared with the experimental data from literatures.22−24 For the binary mixture HFC-32 + HFC125, the average values of the absolute composition deviations for 283.15 K, 293.15 K are 0.0064, 0.0122, respectively, the average values of the absolute relative pressure deviations for 283.15 K and 293.15 K are 0.49 %, 0.36 %. For the binary mixture HFC-32 + HFC-161, the average values of the absolute composition deviations for 283.15 K, 293.15 K are 0.0059, 0.0105, respectively, and the average values of the absolute relative pressure deviations for 283.15 K and 293.15 K are 1.95 %, 1.08 %. For the binary mixture HFC-125 + HFC-161, the average values of the absolute composition deviations for 283.15 K, 293.15 K are 0.0200, 0.0141, respectively, the average

Figure 6. VLE of (HFC-32 (1) + HFC-125 (2) + HFC-161 (3)) with PR + LCVM + NRTL model at 293.15 K. Solid line and dashed line were predicted by PR + LCVM + NRTL model. E



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ACKNOWLEDGMENTS

■

REFERENCES

Article

This work has been supported by the fund of the State Key Laboratory of Technologies in Space Cryogenic Propellants (SKLTSCP 1205) and (SKLTSCP 1314).

(1) Calm, J. M.; Hourahan, G. C. Refrigerant Data Update. HPAC Engineering 2007, 79, 50−64. (2) GTZ. Natural Refrigerants; Gesellschaft fur Technische Zusammenarbeit (GTZ) Yearbook: Germany, 1995. (3) Palm, B. Hydrocarbons as refrigerants in small heat pump and refrigeration systemsa review. Int. J. Refrig. 2008, 31, 552−563. (4) Rocca, V. L.; Panno, G. Experimental performance evaluation of a vapor compression refrigerating plant when replacing R22 with alternative refrigerants. Appl. Energy 2011, 88, 2809−2815. (5) Framework Convention on Climate Change (UNFCCC), Report of the Conference of the Parties, Kyoto Protocol; United Nations: New York, 1997. (6) Robinson, D. M.; Groll, E. A. Efficiencies of trans-critical CO2 cycles with and without an expansion turbine. Int. J. Refrig. 1998, 21, 577−589. (7) Boumaza, M. Performances assessment of natural refrigerants as substitutes to CFC and HCFC in hot climate. Int. J. of Thermal & Environmental Engineering 2010, 1, 125−30. (8) Aprea, C.; Greco, A. Performance evaluation of R22 and R407C in a vapor compression plant with reciprocating compressor. Appl. Therm. Eng. 2003, 23, 215−227. (9) Calm, J. M.; Domanski, P. A. R22 replacement status. ASHRAE J. 2004, 46, 29−39. (10) Han, X. H.; Qiu, Y.; Li, P.; Xu, Y. J.; Wang, Q.; Chen, G. M. Cycle performance studies on HFC-161 in a small-scale refrigeration system as an alternative refrigerant to HFC-410A. Energy Build. 2012, 44, 33−38. (11) Bolaji, B. O. Performance investigation of ozone-friendly R404A and R507 refrigerants as alternatives to R22 in a window airconditioner. Energy Build. 2011, 43, 3139−3143. (12) Piao, C. C.; Taira, S.; Moriwaki, M.; Tanimoto, ; Mochizuki, K. K.; Nakai, A. Alternatives to high GWP HFC refrigerants: residential and small commercial split equipment, ASHRAE/NIST Refrigerants Conference: Gaithersburg, MD, 2012. (13) Lemmon, E. W.; McLinden, M. O.; Huber, M. L. NIST reference fluid thermodynamic and transport propertiesREFPROP, version 9.0; NIST: Gaithersburg, MD, 2010. (14) Han, X. H.; Wang, Q.; Zhu, Z. W.; Chen, G. M. Cycle performance study on R32/R125/R161 as an alternative refrigerant to R407C. Appl. Therm. Eng. 2007, 27, 2559−2565. (15) Han, X. H.; Zhu, Z. W.; Chen, F. S.; Xu, Y. J.; Gao, Z. J.; Chen, G. M. Solubility and Miscibility for the Mixture of (Ethyl Fluoride + Polyol Ester Oil). J. Chem. Eng. Data 2010, 55, 3200−3207. (16) Han, X. H.; Yuan, X. R.; Xu, Z. Z.; Wang, X. H.; Chen, G. M.; Xu, X. G. Research on Compatibility between Ethyl Fluoride with/ without Lubricant Oils and Plastics, Elastomers. Ind. Eng. Chem. Res. 2014, 53, 14650−14658. (17) Han, X. H.; Xu, Y. J.; Min, X. W.; Gao, Z. J.; Wang, Q.; Chen, G. M. Density data for the refrigerant ethyl fluoride (HFC-161) over a temperature range from (233 to 344) K. J. Chem. Eng. Data 2011, 56, 3038−3042. (18) Chen, G. M.; Guo, Z. K.; Guo, X. Z.; Xuan, Y. M. Environmental-friendly refrigerant used to replace HCFC-22. Invention patent, ZL 03116856.6. (19) Peng, D.; Robinson, D. B. A New Two-Constant Equation of State. Ind. Eng. Chem. Fundam. 1976, 15, 59−64. (20) Boukouvalas, C.; Spiliotis, N.; Coutsikos, P.; Tzouvaras, N.; Tassios, D. Prediction of vapor-liquid equilibrium with the LCVM model: a linear combination of the Vidal and Michelsen mixing rules coupled with the original UNIF. Fluid Phase Equilib. 1994, 92, 75− 106.


Figure 9. VLE data of HFC-125 (1) + HFC- 161 (2) at 283.15, 293.15 K. Experimental data are from literature.24 Solid lines were predicted by PR + LCVM + NRTL model.

values of the absolute relative pressure deviations for 283.15 K, 293.15 K are 6.62 %, 4.85 %. It can be found that the predicted results by the ternary mixtures HFC-161 + HFC-32 and HFC32 + HFC-125 have a good agreement with the experimental data from the literatures,22,23 whereas the prediction pressure results for the binary mixture HFC-125 + HFC-16124 are worse than those of other two mixtures. One of the reasons may be that the experimental data in this work still are very limited within the measurement range, which make the interactive parameters obtained by the ternary mixture have some limitation for predicting the phase behavior of the binary mixtures.

■. CONCLUSIONS In this work, the VLE data for the system HFC-32 + HFC-125 + HFC-161 were presented within the temperature range of 265.15 K to 303.15 K by experiment. The vapor−liquid equilibrium data were correlated with PR + LCVM + NRTL model. The correlated results agreed with the experimental data very well, and the average value of the absolute relative pressure deviations was 0.90 %, the average value of the absolute composition deviations (abs (y1 − y1,cal)) was 0.0098, and the average value of the absolute composition deviations (abs (y2 − y2,cal)) was 0.0105. The results further suggested that there was no azeotrope in the ternary mixture of HFC-32 + HFC-125 + HFC-161. The phase behavior of the binary mixtures HFC-32 + HFC-161, HFC-32 + HFC-125 and HFC-125 + HFC-161 at the temperatures of 283.15 K and 293.15 K were predicted and analyzed on the basis of the interactive parameters obtained by correlating the ternary mixtures. It was revealed that, the predicted results for the binary mixtures HFC-32 + HFC-161, HFC-32 + HFC-125 had a good agreement with the experimental data from the literature,22,23 but for the binary mixture HFC-125 + HFC-161,24 the pressure prediction results were not as good as those of the two binary mixtures. The predicted results suggested that the interactive parameters obtained by the ternary mixture may not always be able to have a good prediction result for the responding binary mixtures.

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(21) Renon, H.; Prausnitz, J. M. Local compositions in thermodynamic excess functions for liquid mixtures. AIChE J. 1968, 14, 135−144. (22) Han, X. H.; Chen, G. M.; Cui, X. L.; Wang, Q. Vapor-Liquid Equilibrium Data for the Binary Mixture Difluoroethane (HFC-32) + Pentafluoroethane (HFC-125) of an Alternative Refrigerant. J. Chem. Eng. Data 2007, 52, 2112−2116. (23) Han, X. H.; Gao, Z. J.; Xu, Y. J.; Qiu, Y.; Min, X. W.; Wang, Q.; Chen, G. M. Isothermal Vapor-liquid equilibrium data for the binary mixture difluoromethane (R-32) + ethyl fluoride (R-161) over a temperature range from 253.15 to 303.15K. Fluid Phase Equilib. 2010, 299, 116−121. (24) Han, X. H.; Chen, G. M.; Li, C. S.; Qiao, X. G.; Cui, X. L. Isothermal vapor-liquid equilibrium data for the binary mixture refrigerant pentafluoroethane (R125) + fluoroethane (R161) at 265.15, 275.15, 283.15, 293.15, 303.15 and 303.15K with a recirculating still. J. Chem. Eng. Data 2006, 51, 1232−1235.

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