Burnett Apparatus Research Articles

Gaseous pvTx properties for the binary mixtures of carbon dioxide (CO2) + trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) and carbon dioxide (CO2) + 3,3,3-trifluoropropene (R1243zf)

The gaseous pvTx data of the binary mixtures for carbon dioxide (CO2) + trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) and CO2 + 3,3,3-trifluoropropene (R1243zf) were experimentally measured at 5 isotherms from 333.15 K to 393.15 K. The experiment used a Burnett apparatus and the highest experimental pressure exceeded 7 MPa. The standard uncertainties of temperature, pressure and mole fraction are 10 mK, 0.2 ∼ 0.8 kPa and 0.0015, respectively. The relative uncertainty of the molar density is 0.05 %. Based on the experimental data of pure components and mixtures, three-term truncated virial equations of state (EoS) were established. The relative root mean square deviations (RMSD) of virial EoS in calculating density of CO2 + R1234ze(E) and CO2 + R1243zf mixtures are 0.15 % and 0.05 %, respectively. The virial EoS obtained in this work were compared with REFPROP 10.0 and the literature data, and the virial coefficients were calculated and compared between the experimental value and the calculated value from virial EoS.

Experimental measurements and correlations of the vapor phase pvTx behavior of binary mixtures of 1,1,1,2-tetrafluoroethane (R134a) + 2,3,3,3-tetrafluoroprop-1-ene (R1234yf)

In the present study, the accurate determination of the vapor phase pvTx behavior of binary mixtures of 1,1,1,2-Tetrafluoroethane (R134a) + 2,3,3,3-Tetrafluoroprop-1-ene (R1234yf) by using a Burnett apparatus was demonstrated. Measurements have been performed over the temperature range from (303 to 388) K and at pressures up to 5023 kPa covering the mole fractions of xR134a = (0.000, 0.099, 0.328, 0.523, 0.726, 0.919, 1.000). The combined expanded uncertainties of temperature, pressure, mole fraction and vapor density with a level of confidence of 0.95 (k = 2) were estimated to be 24 mK, 1.6 kPa, 0.01 and within 0.2% over the entire temperature, pressure and mole fraction ranges, respectively. In order to facilitate practical industrial applications and explore the thermophysical behavior of the second and third virial coefficients, the experimental vapor density data of this work were used to develop the virial equation of state with the average absolute deviation of compressibility factor lower than 0.52% for each composition. Furthermore, the obtained gaseous pvTx properties of R134a/R1234yf mixtures were compared with the multi-parameter equation of state of REFPROP 10.0 (Lemmon et al., 2018) and the relative deviations were less than 1.2%.

Experimental vapor pressures and gaseous pvT properties of trans-1-Chloro-3,3,3-trifluoropropene (R1233zd(E))

Abstract In this work, saturated vapor pressures and gaseous pvT properties of a fourth generation refrigerant, trans-1-Chloro-3,3,3-trifluoropropene (R1233zd(E)), were measured using a Burnett apparatus. The vapor pressures were obtained in the temperature range from (288 to 373) K and pressure range from (0.089 to 1.04) MPa. The gaseous pvT properties were obtained in the temperature range from (303 to 373) K, pressure range from (0.091 to 0.99) MPa and density range from (0.038 to 0.40) mol•dm–3. The standard experimental uncertainties were estimated as 4 mK and 0.5 kPa for temperature and pressure, respectively. The relative uncertainty in density is better than 0.1%. A truncated virial equation of state was developed based on the present pvT data.

Saturated vapor pressure and gaseous pvT property measurements for 3,3,3-trifluoroprop-1-ene (R1243zf)

Abstract 3,3,3-trifluoroprop-1-ene (R1243zf) is a potential alternative refrigerant with low global warming potential and 26 saturated vapor pressure data and 128 vapor phase pvT data are presented in this paper. The vapor pressure data were obtained in the temperature range from (253 to 376) K and pressure range from (0.13 to 3.46) MPa. The vapor phase pvT data were measured using a Burnett apparatus for the temperature range from (253 to 368) K, pressure range from (0.11 to 2.89) MPa and density range from (0.05 to 1.82) mol dm–3. The standard experimental uncertainties were estimated as 5 mK and 0.5 kPa for temperature and pressure, respectively. The relative uncertainty in density is better than 0.12%. In addition, the present pvT data were correlated by a truncated virial equation of state with the density average absolute relative deviation of 0.05%.

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3,3,3-trifluoroprop-1-ene (R1243zf) is a potential alternative refrigerant with low global warming potential and 26 saturated vapor pressure data and 128 vapor phase pvT data are presented in this paper. The vapor pressure data were obtained in the temperature range from (253 to 376) K and pressure range from (0.13 to 3.46) MPa. The vapor phase pvT data were measured using a Burnett apparatus for the temperature range from (253 to 368) K, pressure range from (0.11 to 2.89) MPa and density range from (0.05 to 1.82) mol dm–3. The standard experimental uncertainties were estimated as 5 mK and 0.5 kPa for temperature and pressure, respectively. The relative uncertainty in density is better than 0.12%. In addition, the present pvT data were correlated by a truncated virial equation of state with the density average absolute relative deviation of 0.05%.

Vapor Pressure Measurements and Correlation for cis-1,1,1,4,4,4-Hexafluoro-2-butene (HFO-1336mzz(Z))

In this work, 91 vapor pressure data of cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(Z)) were measured using a Burnett apparatus in a temperature range of (278 to 443) K and a pressure range of...

Experimental measurements of saturated vapor pressure and gaseous pvT property for 2,3,3,3-tetrafluoroprop-1-ene (HFO-1234yf)

The saturated vapor pressures and gaseous pvT properties of 2,3,3,3-tetrafluoroprop-1-ene (HFO-1234yf) were measured using a Burnett apparatus. 24 vapor pressure data points were obtained in temperature range from (253 to 367) K and with pressures from (0.15 to 3.34) MPa. The standard experimental uncertainties were estimated to be within 5 mK and 0.5 kPa for temperature and pressure, respectively. The vapor pressure data were correlated by a Wagner type equation with the average absolute deviation of 0.015%. A total of 172 gaseous pvT data were obtained in temperature range from (253 to 368) K, pressure range from (0.097 to 3.37) MPa and density range from (0.038 to 2.86) mol dm–3. The relative uncertainty in density is better than 0.15%. The present data were correlated by a truncated virial equation of state with the average absolute deviation of 0.03% in density.

Vapor Pressure Measurements and Correlation for trans-1-Chloro-3,3,3-trifluoroprop-1-ene

In this work, 95 data points for the vapor pressure of trans-1-chloro-3,3,3-trifluoroprop-1-ene (HCFO-1233zd(E)) were measured over the temperature range of 253–431 K and the pressure range of 17–3091 kPa using a Burnett apparatus. The effect of the presence of impurities on the measurement was carefully analyzed, and the deviations caused by impurities were corrected. The detailed uncertainty analysis was presented, and the combined expanded (k = 2) uncertainty in temperature measurement is 6.2 mK; the combined expanded (k = 2) uncertainty in the vapor pressure ranged from 0.33 to 1.18 kPa. A Wagner-type vapor pressure equation was developed based on the data of the work and those from the literature. The normal boiling temperature of HCFO-1233zd(E) was estimated to be 291.327 K. The available vapor pressure data were compared with the new vapor equation. The enthalpies of vaporization calculated from the new equation were compared with other equations from the literature.

Vapor phase pvTx measurements of binary mixtures of difluoromethane (R32) and 2,3,3,3-tetrafluoroprop-1-ene (R1234yf)

The pvTx properties of binary mixture of difluoromethane (R32) and 2,3,3,3-tetrafluoroprop-1-ene (R1234yf) in the vapor phase were measured at temperatures from (298 to 383) K and at pressures from (475 to 5686) kPa covering the mole fractions of xR32 = (0.119, 0.259, 0.449, 0.698, 0.874) by using a Burnett apparatus. The combined expanded uncertainties of temperatures, pressures, mole fraction and density are estimated to be 24 mK, 1.6 kPa, 0.01 and within 0.2% (k = 2) over the entire temperature and pressure ranges, respectively. Based on the experimental data of this work, a virial equation of state was developed with the absolute average deviation of compressibility factor lower than 0.19% for each composition and this equation shows physically reasonable behaviour of the second and third virial coefficients. Furthermore, the relative deviations of the experimental data from the multi-parameter equation of state of REFPROP 10.0 are less than 0.6% for the mixtures.

Measurements of vapor pressure and gaseous pvT property for trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E))

The saturated vapor pressures and gaseous pvT properties for trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) were measured using a Burnett apparatus. For vapor pressure, 15 data points were obtained in the temperature range from (303–373) K and pressure range from (578–3027) kPa. The experimental data was correlated by a Wagner type equation with the average absolute deviation of 0.003%. For gaseous pvT property, 101 data points were obtained in the temperature range from (313–373) K, pressure range from (117–2831) kPa and density range from (0.05–1.6) mol·dm−3. The second and third virial coefficients along 13 isotherms were obtained. The density data were correlated by a three-term truncated virial equation of state with a relative standard deviation of 0.06%.

Measurements and New Vapor Pressure Correlation for HFO-1234ze(E)

The vapor pressure of HFO-1234ze(E) (trans-1,3,3,3-tetrafluoropropene) was measured from 235 to 381 K for pressures from 40 to 3493 kPa using a Burnett apparatus. The temperature measurement uncertainty was estimated to be 2.3 mK, and the pressure uncertainty was estimated to be 600 Pa. A Wagner-type equation was used to correlate the vapor pressure of HFO-1234ze(E) based on the experimental data. This vapor equation has five coefficients and correlates the vapor pressure data of this work with a maximum relative deviation of 0.00082.

PvT Property of HFE 7100 in the Gaseous Phase

HFE 7100 (C4F9OCH3) is a promising working fluid for organic Rankine cycles (ORC). However, there are no available published experimental gaseous pvT data. Thus, pvT data of HFE 7100 in the gaseous phase were measured with a Burnett apparatus. High purity helium was used to calibrate the cell constant of the Burnett apparatus. Then, the gaseous pvT data of HFE 7100 were measured from (363 to 431) K for pressures from (148 to 878) kPa. The temperature measurement standard uncertainty was estimated to be 2.3 mK, the pressure standard uncertainty was estimated to be 240 Pa, and the density relative standard uncertainty was estimated to be 0.0006. A truncated virial equation of state (EOS) for HFE 7100 was used to correlate the experimental data with a relative root-mean-square deviation of 0.00042.

Vapor Pressure of HFE 7100

The vapor pressure of HFE 7100 was measured from (306 to 431) K for pressures from (36 to 1180) kPa using a Burnett apparatus. The temperature measurement uncertainty was estimated to be ± 5 mK, and the pressure uncertainty was estimated to be ± 300 Pa. A Wagner-type equation was used for the vapor pressure of HFE 7100 based on the experimental data. This equation contains five coefficients and correlates the measured vapor pressures within 0.11 %.

Burnett Measurements and Virial Coefficients for the R32 + N2O System

Experimental results for the difluoromethane (R32) + nitrous oxide (N2O) system are presented in this paper. The Burnett apparatus was calibrated using helium, and its performance was confirmed by measurements for pure N 2O. The values of the virial coefficients for R32 were adopted from previous measurements as the same sample was used in the present study. PVTx measurements were performed for the binary R32 + N2O system for four isotherms (303, 323, 343, and 364 K). Twenty Burnett expansions were performed in a pressure range from 5000 to 150 kPa. The second and third virial coefficients along with the cross second and third virial coefficients were derived from experimental results.

Vapor pressure measurements of 1,1,1-trifluoroethane (HFC-143a) and 1,1,1,3,3,3-hexafluoropropane (HFC-236fa)

The vapor pressures of 1,1,1-trifluoroethane (HFC-143a) and 1,1,1,3,3,3-hexafluoropropane (HFC-236fa) were measured with a modified Burnett apparatus. The vapor pressures were measured at temperatures from 251 to 343 K and pressures from 292 to 3553 kPa for HFC-143a, and at temperatures from 253 to 396 K and pressures from 43 to 3064 kPa for HFC-236fa. The measurement uncertainties were estimated to be within ±10 mK and ±1.2 kPa. Two vapor pressure equations were developed to represent the experimental data for HFC-143a and HFC-236fa, respectively. The results were also compared with available literature data.

Vapor Pressures of 1,1,1,3,3-Pentafluoropropane (HFC-245fa) and 1,1,1,2,3,3,3-Heptafluoropropane (HFC-227ea)

The vapor pressures of 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) and 1,1,1,3,3-pentafluoropropane (HFC-245fa), two ozone-friendly fluorinated propane derivatives, were measured with a modified Burnett apparatus. The vapor pressures were measured at temperatures from (253 to 373) K and pressures from (87 to 2824) kPa for HFC-227ea and at temperatures from (255 to 393) K and pressures from (21 to 1950) kPa for HFC-245fa. The measurement uncertainties were estimated to be within ±10 mK and within ±1 kPa. The Wagner-type vapor pressure equations were used to correlate the experimental data for HFC-227ea and HFC-245fa, respectively. The results were also compared with available literature data.

Thermodynamic Property Measurements for Trifluoromethyl Methyl Ether and Pentafluoroethyl Methyl Ether

PVT properties are presented for both the gas-phase and liquid-phase, vapor pressures and saturated-liquid densities for hydrofluoroether (HFE) refrigerants, trifluoromethyl methyl ether (CF3OCH3) and pentafluoroethyl methyl ether (C2F5OCH3), that were obtained with a Burnett apparatus and a vibrating-tube densimeter. A total of 250 liquid densities and 70 gas-phase PVT properties for CF3OCH3 and 281 liquid densities and 125 gas-phase PVT properties for C2F5OCH3 were obtained in wide ranges of temperature (240 to 380) K and pressure up to 7 MPa with a rapid density measurement system with a vibrating-tube densimeter. For CF3OCH3, 109 gas-phase PVT properties were obtained with a Burnett apparatus at the temperatures (300 to 380) K and up to nearly the critical density. On the basis of the present measurements, we have also developed thermodynamic models to complement the experimental data. Equations of state for the liquid phase and truncated virial equations of state are discussed in this paper, as well ...

CO 2 + R23 Binary System: Virial Coefficients Derived from Burnett Measurements

Burnett PVT measurements were performed on trifluoromethane (R23) and mixtures of R23 with carbon dioxide (CO2). The Burnett apparatus was calibrated using helium. Fourteen expansions were performed for 5 isotherms and in a pressure range from 130 kPa to 6 MPa for R23. Second and third virial coefficients were derived from the collected data and compared with literature values; good agreement was found between them. PVTx measurements for the binary CO2+R23 system were carried out for five isotherms (303, 313, 323, 333, and 343 K). In all, 18 runs were performed in a pressure range from 150 kPa to 5.9 MPa. The composition of the mixtures was measured with a gas chromatograph after it had been calibrated using samples prepared gravimetrically. Second and third virial coefficients for the system were derived, together with the second and third cross virial coefficients, from experimental results using virial coefficients for CO2 from previous measurements (for the same sample as used in the present study). Samples for composition measurements were collected during the first Burnett expansion. Second virial coefficients for the system showed positive deviations from ideal values, while the third virials were negative. No previous experimental results were found for the PVTx properties of this binary system.

Measurements of Gas-Phase PVTx Properties for the Ternary Mixtures Difluoromethane (1) + Pentafluoroethane (2) + 1,1,1-Trifluoroethane (3)

As one of the promising alternative refrigerants to replace R-502 [R-22 + R-115 (xR-22 = 0.63, where x denotes mole fraction)], the gas-phase thermodynamic properties of the ternary mixture R-32 (difluoromethane) (1) + R-125 (pentafluoroethane) (2) + R-143a (1,1,1-trifluoroethane) (3) have been studied. A total of 220 gas-phase PVTx properties for the present ternary system, R-32 + R-125 + R-143a, was obtained at four different compositions, (x1 = 0.174, x2 = 0.340), (x1 = 0.313, x2 = 0.203), (x1 = 0.343, x2 = 0.445), and (x1 = 0.484, x2 = 0.216), by using the Burnett apparatus. The present measurements range widely in temperature (305 to 380) K, pressure up to 4.6 MPa, and density up to 200 kg·m-3. The uncertainties of the present study are estimated to be within 7 mK in temperature, (0.8 to 2.5) kPa in pressure, 0.15% in density, and 0.1 mol % in composition. The second and third virial coefficients for the mixtures, Bm and Cm, were also obtained from the present isothermal PVTx data. The consistency of the present measurements was confirmed by comparing them with the virial equation of state for the mixture of interest developed by the present authors and REFPROP. An excellent agreement between the present measurements and those models was confirmed to be within ±0.4% for pressure and ±0.1% for the mixture second virial coefficients.

Second and third virial coefficients of three binary mixtures containing xenon, at 273 K: Comparison between Xe + C2H6, Xe + C2H4and Xe + CO2

This paper presents volumetric data for the mixtures xenon–ethane, xenon–ethene and xenon–carbon dioxide, with xenon mole fractions covering the whole composition range, at 273.00 K and pressures up to 3.5 MPa, measured using a Burnett apparatus. Second and third virial coefficients were derived for each mixture from the experimental compressibility factors, Z. Data for the pure components are also determined for consistency purposes and for the calculation of the unlike-interaction virial coefficients, B12, C112 and C122. Corrections for the effects of adsorption, and the procedure for computation of the compressibility factors and virial coefficients are described. In order to accomplish a better understanding of the intermolecular forces present in real fluids, the cross virial coefficients, B12, of the studied systems were theoretically calculated using a two centre Lennard–Jones (L–J) model, and compared with experimental data. The importance of the third virial cross coefficients C112 and C122 is discussed.