Simultaneous Measurement of Dynamic Viscosity and Density of n

Oct 24, 2017 - Tools & Sharing. Add to Favorites · Download Citation · Email a Colleague · Order Reprints · Rights & Permissions · Citation Alerts · A...
8 downloads 12 Views 2MB Size
Download PDF
Article Cite This: J. Chem. Eng. Data XXXX, XXX, XXX-XXX

pubs.acs.org/jced

Simultaneous Measurement of Dynamic Viscosity and Density of n‑Alkanes at High Pressures Alfredo Pimentel-Rodas, Luis A. Galicia-Luna,* and José J. Castro-Arellano Laboratorio de Termodinámica, S.E.P.I.-E.S.I.Q.I.E. Instituto Politécnico Nacional, UPALM, Edif. Z, Secc. 6, 1ER piso, Lindavista C.P., 07738 México D. F., México ABSTRACT: New experimental data of the dynamic viscosity and density of pentane, octane, nonane, decane, and dodecane are reported. The experimental method was validated by determining and comparing the dynamic viscosity and the density of decane with the data previously published in the international literature, obtaining a maximum deviation of 12 μPa·s and 0.35 kg·m−3 for dynamic viscosity and density, respectively. The measurements were performed simultaneously using a capillary tube viscometer and a vibrating tube densimeter at temperatures between 293 and 353 K and pressures up to 30 MPa. The estimated relative combined expanded uncertainties (k = 2), considering the impurities of the compounds (including content of water), are 0.9% for the dynamic viscosity and 0.13% for the density over the entire measurement range. The viscosity data were successfully correlated as a function of pressure and temperature with an empirical model proposed in this study. Also, the experimental density data were successfully modeled with an equation previously published in the international literature. Besides, the experimental density data were used to obtain the isothermal compressibilities and isobaric thermal expansivities. viscosity, both important for simulating the behavior of the fluid under reservoir conditions, and for testing the effectiveness of empirical models.8 Recently,9 we had reported the design of an instrument capable of simultaneously determining the dynamic viscosity and

1. INTRODUCTION Fluid viscosity has a particular importance for the design of process equipment as it characterizes the fluids in question (in terms of flow resistance). This property allows us to know dimensionless variables, such as Reynolds number, Grashof number, Prandtl number, etc., reducing overdesign factors.1−3 Some of the most commonly used methods for experimental determination of dynamic viscosity require the knowledge of the density of the fluid, as in the capillary and the descending body methods.4−6 The density could be calculated through a state equation, if available. Alternatively, the best option is to experimentally determine the density at the same temperature and pressure conditions (within experimental uncertainty). Employing a simultaneous method of measurement, it does not matter whether or not there is a precise equation which represents the density of the fluid. In addition, simultaneous measurements have the advantage of eliminating errors involved in the reproduction of identical temperature and pressure conditions in different instruments.6 Density is one of the most important physical properties and its measurement have been required in many industrial processes, such as the production and refining of petrol, oil, and gas industries, oil recovery technology, and design calculations. The fundamental properties, which could be determined from the density, are the coefficient of isothermal compressibility and the coefficient of isobaric thermal expansion.7 The knowledge of the density at different temperature and pressure conditions is not only necessary in many industrial applications, is also essential for the calculation of properties such as solubility or © XXXX American Chemical Society

Table 1. Compound Information compound

source

mass fraction puritya

purification method

N2 water pentane octane nonane decane dodecane

Infra Air Products Sigma-Aldrich Sigma-Aldrich Sigma-Aldrich Sigma-Aldrich Sigma-Aldrich Sigma-Aldrich

0.99995 0.9995 (HPLC) 0.994 (reagent) 0.995 (anhydrous) 0.994 (HPLC) 0.995 (HPLC) 0.994 (HPLC)

none none none none none none none

a

Analysis method: Gas chromatography.

the density of liquid fluids, which we use to carry out experimental measurements of these same thermophysical properties of alkanes and alcohols up to 353 K and 30 MPa. In the present work, simultaneously measurements of the dynamic viscosity and the density of five alkanes in liquid phase (pentane, octane, nonane, decane and dodecane) at temperatures between 293 and 353 K Received: July 16, 2017 Accepted: October 11, 2017

A

DOI: 10.1021/acs.jced.7b00650 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Figure 1. Experimental system used for the simultaneous determination of viscosity and density: (TRP1, TRP2) pressure transducers, (2) pressure and pressure drop indicator, (T1, T2) platinum probes, (1) temperature indicator, (VTD) vibrating tube densimeter, (SP) syringe pump, (VP) vacuum pump, (V1, V2) valves, (PC) computer, (ESC) purge.

Figure 2. Density data of decane obtained in this study as a function of pressure at 323.15 K compared with literature values. (▼) Assael et al.;23 (■) Audonnet and Pádua;24 (●) Caudwell et al.;26 (▲) Sato et al.;27 (⧫) This work.

Figure 3. Dynamic viscosity data of decane obtained in this study as a function of pressure at 323.15 K compared with literature values. (▼) Assael et al.;23 (■) Audonnet and Pádua;24 (●) Caudwell et al.;26 (▲) Sato et al.;27 (⧫) This work.

and up to 30 MPa of pressure were performed. The data was obtained using a vibrating tube densimeter coupled to a capillary tube viscometer, allowing the determination of both thermophysical properties. In order to verify the viability of the obtained data, the experimental methodology was validated through comparisons between obtained results and previously published decane data. The relative combined expanded uncertainty was evaluated to be less than 0.90% and 0.13% for the dynamic viscosity and the density, respectively, considering the effect of sample impurity. The viscosity and density data were correlated using an empirical equation proposed in this work as well as a model previously published in the international literature, respectively. Also, the experimental density data were used to obtain the isothermal compressibility (KT) and the isobaric thermal expansivity (αP).

(anhydrous), decane with purity 99.5% (HPLC grade), dodecane with purity of 99.4%, and water HPLC grade were acquired from Sigma-Aldrich. Merck supplied ethanol with purity of 99.9% (maximum content of water of 0.01%). The manufacturers provided the samples purities through certificates of analysis (GC tests). All samples were carefully degassed by agitation under vacuum prior to injection into the system and were used without further purification. In Table 1, the supplier and purity of all compounds used in this work are presented. Karl Fischer coulometer (Metrohm, 831) was used for determining the water contents for all compounds and the results are pentane 5.73 × 10−4 mass fraction, octane 5.52 × 10−4 mass fraction, nonane 5.96 × 10−4 mass fraction, decane 6.12 × 10−4 mass fraction, and dodecane 6.05 × 10−4 mass fraction. Standard uncertainty of content of water is 0.28 × 10−4 mass fraction. Measurement System. The viscosity and density were measured simultaneously using a capillary tube viscometer and a vibrating tube densimeter. A schematic diagram of the measuring

2. EXPERIMENTAL SECTION Materials. Pentane with purity 99.4% (reagent grade), octane with purity 99.5% (anhydrous), nonane with purity 99.4% B

DOI: 10.1021/acs.jced.7b00650 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 2. Experimental Values of Dynamic Viscosity (ηexp) and Density (ρexp) and Calculated Values of Isothermal Compressibility (KT) and Isobaric Thermal Expansivity (αP) at Temperature (T) and Pressure (P) of Decanea T/K

P/MPa

ρexp/kg·m−3

ηexp/μPa·s

KT · 104/MPa−1

αP · 104/K−1

303.152 303.151 303.152 303.154 303.155 303.151 303.152 303.150 303.151 303.151 303.150 303.152 323.152 323.150 323.149 323.153 323.151 323.154 323.153 323.152 323.154 323.152 323.154 323.153 353.156 353.157 353.155 353.155 353.156 353.157 353.158 353.156 353.155 353.156 353.156 353.157

2.001 3.991 6.003 8.001 9.992 13.006 16.005 18.998 21.997 25.008 27.989 29.988 1.995 4.003 5.997 8.005 10.006 12.995 15.989 18.994 21.997 25.006 28.004 30.005 2.000 3.999 5.998 7.997 9.991 13.003 15.994 19.005 22.010 25.000 27.992 29.995

724.01 725.58 727.19 728.75 730.27 732.50 734.69 736.88 739.00 741.03 743.02 744.30 708.76 710.68 712.57 714.30 715.96 718.36 720.73 723.00 725.28 727.50 729.62 731.03 685.65 687.9 689.96 691.97 694.06 697.01 699.86 702.43 704.95 707.44 710.01 711.67

807.9 826.8 846.1 865.5 885.0 915.0 944.5 973.4 1004.0 1035.0 1065.9 1086.2 624.9 638.6 652.9 667.6 682.4 704.5 727.4 751.1 774.0 798.1 822.0 838.2 448.0 459.6 471.4 482.5 494.0 510.6 527.2 544.2 561.2 578.8 596.7 608.6

11.64 11.34 11.05 10.77 10.5 10.11 9.75 9.40 9.08 8.77 8.47 8.28 13.19 12.84 12.51 12.19 11.88 11.44 11.02 10.63 10.25 9.90 9.56 9.35 15.65 15.23 14.83 14.44 14.07 13.54 13.04 12.56 12.12 11.69 11.29 11.03

10.43 10.28 10.14 10.00 9.86 9.66 9.47 9.29 9.11 8.94 8.78 8.68 10.77 10.62 10.47 10.32 10.17 9.97 9.77 9.57 9.39 9.21 9.04 8.93 11.09 10.93 10.76 10.61 10.46 10.24 10.02 9.82 9.63 9.44 9.26 9.14

a Combined uncertainties uc are uc(P) = 0.002 MPa, uc(T) = 0.007 K; relative combined uncertainty for isothermal compressibility, urc(KT) = 0.012 and for isobaric thermal expansivity urc(αP) = 0.006; the relative combined expanded uncertainty with a 0.95 level of confidence (k = 2) for the density, Urc(ρexp) = 0.0013 and for dynamic viscosity, Urc(ηexp) = 0.009.

Figure 4. Viscosity of pentane obtained in this study over a wide range of pressures. (■) T = 293.216 K; (●) T = 313.103 K; (▲) T = 333.009 K; (▼) T = 353.123 K; (−) solid lines represent the proposed correlation.

Figure 5. Density of pentane obtained in this study over a wide range of pressures. (■) T = 293.216 K; (●) T = 313.103 K; (▲) T = 333.009 K; (▼) T = 353.123 K; (−) solid lines represent the model used. C

DOI: 10.1021/acs.jced.7b00650 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 3. Experimental Values of Dynamic Viscosity (ηexp) and Density (ρexp) and Calculated Values of Isothermal Compressibility (KT) and Isobaric Thermal Expansivity (αP) at Temperature (T) and Pressure (P) of Pentanea T/K

P/MPa

ρexp/kg·m−3

ηexp/μPa·s

KT · 104/MPa−1

αP · 104/K−1

293.211 293.214 293.213 293.211 293.217 293.214 293.220 293.219 293.218 293.219 293.217 293.213 313.103 313.105 313.102 313.104 313.104 313.104 313.103 313.100 313.102 313.102 313.102 313.102 333.007 333.006 333.007 333.010 333.012 333.011 333.011 333.008 333.007 333.010 333.010 333.009 353.121 353.120 353.122 353.122 353.123 353.124 353.123 353.122 353.126 353.125 353.124 353.122

2.000 3.998 6.000 8.003 10.008 13.008 16.007 19.009 22.010 25.002 28.002 30.000 2.005 4.002 6.001 7.999 10.005 13.001 16.005 19.002 22.002 25.004 28.002 30.005 2.009 3.997 6.002 8.008 10.001 12.998 15.996 19.000 21.997 25.000 27.997 30.006 2.006 3.997 6.002 8.003 10.008 13.000 16.001 18.997 22.000 25.002 28.005 30.001

628.05 630.31 632.63 634.89 636.91 640.02 643.00 645.81 648.59 651.19 653.72 655.38 608.49 611.31 613.99 616.58 619.09 622.65 626.03 629.28 632.38 635.40 638.20 640.09 587.87 591.40 594.59 597.69 600.61 604.82 608.78 612.50 616.10 619.39 622.68 624.71 565.77 570.01 574.02 577.79 581.28 586.31 590.90 595.21 599.29 603.10 606.77 609.10

232.0 238.2 243.9 249.5 255.1 263.7 271.9 280.6 288.5 296.7 304.6 310.0 196.8 202.3 207.5 212.6 218.0 225.9 233.4 240.9 248.5 255.8 262.8 267.6 167.9 173.7 178.7 183.7 188.8 195.8 202.9 210.0 217.0 223.9 230.6 234.8 145.2 150.4 155.7 160.6 165.4 172.4 179.2 185.7 192.2 198.7 204.7 208.7

20.58 19.54 18.57 17.67 16.83 15.69 14.66 13.73 12.88 12.11 11.41 10.97 25.19 23.89 22.69 21.58 20.54 19.13 17.85 16.70 15.66 14.71 13.84 13.31 30.33 28.74 27.26 25.90 24.64 22.92 21.37 19.96 18.70 17.55 16.51 15.86 36.02 34.10 32.31 30.67 29.14 27.07 25.21 23.53 22.02 20.65 19.40 18.63

15.33 14.90 14.50 14.12 13.76 13.25 12.78 12.34 11.93 11.54 11.18 10.96 16.69 16.21 15.76 15.33 14.93 14.36 13.84 13.35 12.89 12.47 12.07 11.82 17.78 17.26 16.77 16.30 15.86 15.24 14.66 14.13 13.64 13.18 12.74 12.47 18.71 18.14 17.60 17.09 16.61 15.94 15.32 14.75 14.22 13.73 13.27 12.98

a Combined uncertainties uc are uc(P) = 0.002 MPa, uc(T) = 0.007 K; relative combined uncertainty for isothermal compressibility, urc(KT) = 0.012 and for isobaric thermal expansivity urc(αP) = 0.006; the relative combined expanded uncertainty with a 0.95 level of confidence (k = 2) for the density, Urc(ρexp) = 0.0013 and for dynamic viscosity, Urc(ηexp) = 0.009.

system is shown in Figure 1.9 Briefly, the instrument consists of a syringe pump (SP), which has a standard uncertainty of 1 × 10−4 cm3·min−1, a vibrating tube densimeter (VTD), with a standard uncertainty of 0.2 kg·m−3, two pressure indicators (TRP1 and TRP2) placed at the ends of the capillary tube, with a standard relative uncertainty of 0.02%, two temperature indicators placed on the side of the capillary tube and in the VTD, with a standard uncertainty of 0.005 K, three temperature regulators

which maintain the temperature with stability of 0.004 K (capillary tube, VTD, and cylinders containing the fluid under study), and an electronic data acquisition unit. The length and internal radius of the capillary tube and its respective standard deviation are 7.550 × 10−1 m ± 1 × 10−3 m and 1.259 × 10−4 m ± 7 × 10−7 m, respectively. It should be noted that all measurements were performed within a maximum temperature difference, between the capillary tube and the VTD, of 0.002 K (validated by measuring D

DOI: 10.1021/acs.jced.7b00650 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 4. Experimental Values of Dynamic Viscosity (ηexp) and Density (ρexp) and Calculated Values of Isothermal Compressibility (KT) and Isobaric Thermal Expansivity (αP) at Temperature (T) and Pressure (P) of Octanea T/K

P/MPa

ρexp/kg·m−3

ηexp/μPa·s

KT · 104/MPa−1

αP · 104/K−1

293.214 293.217 293.216 293.210 293.216 293.213 293.219 293.220 293.219 293.220 293.218 293.214 313.107 313.109 313.104 313.106 313.106 313.106 313.105 313.102 313.103 313.103 313.103 313.103 333.008 333.008 333.009 333.008 333.010 333.009 333.009 333.006 333.005 333.008 333.008 333.007 353.119 353.118 353.121 353.121 353.122 353.127 353.126 353.120 353.124 353.123 353.122 353.120

1.996 3.994 6.001 8.004 10.009 13.010 16.009 19.011 22.012 25.004 28.004 30.002 2.007 4.000 5.999 7.997 10.009 13.005 16.009 19.006 21.998 25.000 27.998 30.001 2.005 3.993 5.998 8.014 10.007 13.004 16.002 19.006 22.003 25.006 28.003 30.012 2.008 3.999 6.000 8.001 10.006 13.003 16.004 19.000 22.003 25.005 28.008 30.004

703.76 705.71 707.57 709.25 710.88 713.21 715.43 717.57 719.76 721.88 724.19 725.54 688.27 690.26 692.07 693.85 695.59 698.26 700.84 703.50 706.05 708.39 710.67 712.15 672.19 674.49 676.69 678.82 680.80 683.60 686.47 689.24 691.91 694.49 696.99 698.61 655.38 657.99 660.50 663.11 665.45 668.83 672.05 674.99 677.96 680.81 683.56 685.34

551.2 563.1 575.2 587.4 599.7 618.3 637.1 656.6 675.9 695.4 715.2 728.5 440.2 449.7 459.3 469.0 478.8 493.5 508.3 523.4 538.5 553.9 569.4 579.8 360.1 368.1 376.1 384.1 392.1 404.3 416.6 428.9 441.4 453.9 466.6 475.1 297.4 304.3 311.2 318.1 325.0 335.4 345.8 356.3 366.9 377.5 388.2 395.4

13.03 12.63 12.24 11.87 11.52 11.02 10.56 10.12 9.71 9.32 8.96 8.73 15.00 14.53 14.09 13.66 13.25 12.67 12.13 11.62 11.14 10.70 10.28 10.01 17.10 16.56 16.04 15.54 15.07 14.41 13.79 13.20 12.65 12.14 11.66 11.35 19.31 18.70 18.11 17.54 17.00 16.24 15.53 14.87 14.24 13.66 13.11 12.76

11.22 11.03 10.85 10.67 10.50 10.25 10.01 9.79 9.57 9.37 9.17 9.05 11.68 11.48 11.29 11.10 10.92 10.66 10.41 10.17 9.94 9.72 9.51 9.38 12.01 11.8 11.59 11.40 11.21 10.93 10.67 10.42 10.18 9.95 9.74 9.60 12.24 12.02 11.81 11.60 11.40 11.12 10.84 10.59 10.34 10.10 9.88 9.73

a

Combined uncertainties uc are uc(P) = 0.002 MPa, uc(T) = 0.007 K; relative combined uncertainty for isothermal compressibility, urc(KT) = 0.012 and for isobaric thermal expansivity urc(αP) = 0.006; the relative combined expanded uncertainty with a 0.95 level of confidence (k = 2) for the density, Urc(ρexp) = 0.0013 and for dynamic viscosity, Urc(ηexp) = 0.009.

the temperature in the capillary tube and in the VTD). The third temperature regulator is a preheater that allows to minimize the temperature gradient in the capillary tube feed. On the other hand, the pressure drop generated in the capillary tube is too low (