Solubilities, Vapor Pressures, Densities, Viscosities, and Specific Heat

Article pubs.acs.org/jced

Solubilities, Vapor Pressures, Densities, Viscosities, and Specific Heat Capacities of the LiNO3/H2O Binary System Chunhuan Luo, Qingquan Su,* and Wanliang Mi School of Mechanical Engineering, University of Science & Technology Beijing, Beijing, China ABSTRACT: The solubility, vapor pressure, density, viscosity, and specific heat capacity of LiNO3/H2O were measured in this work. The solubilities were measured in ranges of temperature from 277.15 K to 431.15 K. The vapor pressures were measured in ranges of temperature and absorbent mass fraction from 297.65 K to 473.15 K and from 50 % to 70 %. The densities and viscosities were measured in ranges of temperature and absorbent mass fraction from 283.15 K to 413.15 K and from 30 % to 65 %. The specific heat capacities were measured in ranges of temperature and absorbent mass fraction from 303.15 K to 373.15 K and from 30 % to 60 %. Regression equations for solubility, vapor pressure, density, viscosity, and specific heat capacity were obtained by a least-squares method from the experimental data. The average absolute relative deviations of each property between the measured data and the individual calculated value from these regression equations were 0.13 %, 0.14 %, 0.12 %, 0.14 %, and 0.23 %, respectively. This research will be helpful when LiNO3/H2O is utilized as a working fluid for the absorption heat pump. choosing suitable working fluids for different absorption cycles in practical applications. Some thermophysical properties of LiNO3/H2O have been reported in previous literature. Donnan and Burt10 measured the solubility of LiNO3 solution in detail at temperatures from 273.25 K to 344.05 K, and the data are also listed in Solubilities of Inorganic and Metal Organic Compounds.11 There are extensive solubility data available for LiNO3 solution from the International Critical Tables (273.15 K to 383.15 K).12 Campbell and Bailey13 investigated the system of LiNO3/ H2O and provided its solubility in a temperature range from 255.45 K to 348.75 K. The recent measurement by Zeng et al.14 devoted mainly to the ternary LiNO3 + LiCl + H2O also contained some study of solubility in the binary LiNO3/H2O system (273.15 K to 342.55 K). The solubility data for lithium nitrate were recently reviewed by Eysseltová and Orlova.15 Campbell et al.16 also measured the vapor pressure of LiNO3 solution in ranges of temperature and mass concentration from 303.15K to 378.15 K and from 10 wt % to 64.953 wt %. The article reported by Sacchetto et al.17 was devoted to the determination of the vapor pressure of LiNO3 solution at temperatures varying from 320 K to 380 K, and at concentrations varying from 0.0753 wt % to 30 wt %. Vapor pressures of LiNO3 solutions with molalities of (0.181 mol·kg−1, 0.526 mol·kg−1, 0.963 mol·kg−1, 1.730 mol·kg−1, 2.990 mol·kg−1, and 5.25 mol·kg−1) have been recently measured by Abdulagatov and Azizov18 in the temperature range from 423.15 K to 623.15 K by the static method. For the vapor pressure of LiNO3 solutions, data were also reported by

1. INTRODUCTION The absorption heat pump is a device which can be driven with renewable energy (geotherm and solar energy) and low grade industrial waste heat, for refrigeration or heating. Therefore, it has been the object of much focus and development in recent years.1,2 The performance of the absorption heat pump greatly depends on thermophysical properties of the working fluids. As a traditional working fluid, LiBr−H2O has problems of strong corrosion and crystallization which are difficult to overcome. To take place of LiBr−H2O, a large number of new working fluids have been investigated. Grover and Devotta3 analyzed the performance of a small absorption cooler with the working fluids of LiCl/H2O and LiBr−LiCl/H2O (mass ratio = 1:1), respectively. By comparing the performance data with the published data for LiBr/H2O, it was found that, for a given cooling duty, the LiBr−LiCl/H2O appears to require the least generator heat load. Iyoki4 measured the solubilities of LiBr−LiI/H2O (mole ratio = 4:1) and LiCl−LiNO3/H2O (mole ratio = 2.8:1) in a range of temperature from 277.75 K to 415.15 K. Patil et al.5 measured the vapor pressures of LiNO3/H2O, LiNO3−LiBr/H2O (mole ratio = 0.88:0.12), and LiNO3−LiCl/H2O (mole ratio = 0.7:0.3) in ranges of temperature and mass concentration from 303.15 K to 373.15 K and from 9.874 wt % to 60.687 wt %. Based on the research of Stephan et al.,6 Romero et al.7 investigated the performance of absorption heat pump using NaOH−KOH−CsOH/H2O (mass ratio = 40:36:24) as working fluid, and the result showed that the cycle with NaOH−KOH−CsOH/H2O has a larger range of operation temperature than that with LiBr/H 2 O. Yoon et al. 8 demonstrated that LiBr−LiI−LiNO3−LiCl has a greater effect on heat and mass transfer than LiBr/H2O. Sun et al.9 summarized some research about working fluids useful for © 2013 American Chemical Society

Received: October 5, 2012 Accepted: January 23, 2013 Published: February 7, 2013 625

dx.doi.org/10.1021/je301084m | J. Chem. Eng. Data 2013, 58, 625−633

Journal of Chemical & Engineering Data

Article

Pearce and Nelson19 (0.10058 mol·kg−1 to 12.8639 mol·kg−1, 298.15 K), Puchkov and Matashkin20 (up to 9.98 mol·kg−1, 423.15 K to 573.15 K), and the International Critical Tables21 (303.15 K to 373.15 K). The density and viscosity were usually measured together in many papers. Campbell et al.22 measured the density and viscosity of LiNO3 solution at temperatures of 298.15 K (0.0635 wt % to 62.36 wt %) and 383.15 K (0.701 wt % to 67.10 wt %). Wimby and Berntsson23 measured the density (10.84 wt % to 48.33 wt %, 293.15 K to 343.15 K) and viscosity (27.93 wt % to 42.01 wt %, 298.15 K to 343.15 K) of five binary systems including LiNO3/H2O and provided a correlation for the density. Roy et al.24 also measured the density and viscosity at several temperatures (303 K, 308 K, 313 K, 318 K, and 323 K) and at light concentrations. Abdulagatov and Azizov25,26 reviewed the experimental density and viscosity data briefly and measured the density (0.181 mol·kg−1, 0.526 mol·kg−1, 0.963 mol·kg−1, and 1.728 mol·kg−1) and viscosity (0.265 mol·kg−1, 0.493 mol·kg−1, 1.074 mol·kg−1, and 1.540 mol·kg−1) of LiNO3 solution at the temperatures varying from 298 K to 573 K in two articles, respectively. The density and viscosity are also listed in the International Critical Tables.27,28 For the specific heat capacity of LiNO3 solution, no experimental data available in previous literature were found except for the data from the International Critical Tables29 (up to 2 mol·kg−1, 291.15 K to 293.15 K). The thermophysical data of LiNO3/H2O were reported in many papers, but the measurement ranges of temperature and concentration were limited, and the data could not meet our needs completely. Authors investigated the thermophysical properties as well as corrosivity of LiNO3/H2O binary system systematically in relatively extensive ranges of temperature and concentration, and this paper is concerned with the experimental data of solubility, vapor pressure, density, viscosity, and specific heat capacity.

Figure 1. Schematic figure of the atomic absorption spectrophotometer.

HNO3 (0.5 wt %) as the medium, and KCl (2 mg·mL−1) solution as the ionization inhibitor were added into the dilute solution, so the sample of lithium ion solution for the atomic absorption spectrophotometer for lithium ion analysis was prepared. Based on the absorbance of sample and calibration curve (R2 = 0.9998) which was obtained by one set of standard lithium solutions (0 μg·mL−1, 1.0 μg·mL−1, 2.0 μg·mL−1, 3.0 μg·mL−1, 4.0 μg·mL−1, and 5.0 μg·mL−1), the concentration of lithium ion was determined. The solubility of LiNO3/H2O was obtained according to the following equation: w = 9.932·10−6 ·

n·c Li·VLi msolution

(1)

where w (wt %) is the mass fraction of LiNO3 saturated solution, n is the dilution multiple, cLi (μg ·ml−1) is the concentration of lithium ion solution, VLi (mL) is the volume of lithium ion solution, and msolution (g) is the mass of LiNO3 saturated solution. Experiments on solubility of LiNO3/H2O were carried out in three replicates for each temperature. Results showed the differences of solubility in repeat runs were smaller than 1.0 %. The validity of the apparatus was tested by LiNO3 solution with the mass fraction of 50 %. The relative deviations between the measured data and the actual data were 0.76 %. The vapor pressure of the LiNO3/H2O binary system was measured by the static method. The experimental apparatus was primarily consisted of a DKU-30 constant temperature oil bath (Jinghong, Shanghai), a Pt-100 thermocouple, a solution autoclave (700 mL), a vacuum valve, a vacuum pump, a AX-110 precision digital absolute pressure meter with the accuracy of 50 Pa, and range of 0 kPa to 110 kPa (Aoxin, Xi’an), a YB150H vacuum pressure gauge with the accuracy of 0.25 % full scale and range of −0.1 MPa to 1.5 MPa (Brighty, Beijing) and a magnetic stirrer. The precision digital absolute pressure meter was used when the vapor pressure was less than 100 kPa. The connecting pipe was wrapped up with the cotton insulation. The schematic figure is shown in Figure 2. After detection of the sealing performance of the system, about 500 mL of LiNO3 aqueous solution was carefully poured into the solution autoclave, sealed with Teflon ring, and vacuated with vacuum pump. Then the solution autoclave was placed in the oil bath. After thermal equilibrium was reached, the temperature of the solution and the corresponding pressure were measured. Three repetitions were carried out for each concentration and temperature. Vapor pressure differences smaller than 0.6 % (P ≤ 100 kPa) and 2 % (P > 100 kPa) in repeat runs were obtained. The mass loss of solution was less than 2 g in the vacuuming process. Considering that the weight of solution was over 650 and 2 g of water was added additionally, the error of concentration was evaluated to be less than 0.2 %. The vapor pressure of water was measured in a range of temperature from 293.15 K to 427.35 K, and compared with the data from ref 30.

2. EXPERIMENTS 2.1. Materials. LiNO3 (GR, > 99.5 wt %), NaCl (GR, > 99.5 wt %), and KCl (GR, > 99.8 wt %) reagents used in this work were supplied by Tianjin Jinke Institute of Fine Chemicals (China) without further purification. HNO3 (AR, 65 to 68 wt %) reagent used in this paper was supplied by Beijing Chemical Works (China). Pure water with an electric resistance of 18.2 MΩ·cm was produced by a superpure water device (TTL-10B, Tongtailian Co. Beijing). 2.2. Apparatus and Procedure. The experimental apparatus for solubility measurement consisted of a SYP1003H precision viscometer oil bath (Zhongxi, Beijing), Erlenmeyer flasks, volumetric flasks, a magnetic stirrer, a BSA224S analytic balance (Sartorius, Germany), and a TAS990 atomic absorption spectrophotometer (Purkinje General Co. Beijing). The schematic figure of atomic absorption spectrophotometer is given in Figure 1. Mixtures of LiNO3 and pure water were prepared with an Erlenmeyer flask, and then it was immersed in the precision viscometer oil bath. The saturated solution and crystal generated in the flask were stirred with a magnetic stirrer at a certain temperature for 36 h and kept static for about 12 h. About 2 g of saturated solution was taken out from Erlenmeyer flask with a dropper and fixed to 1000 mL in the volumetric flask with pure water. The solution in volumetric flask was diluted about 100 times with volumetric flask and the pipettes of A grade (Sujing, Nanjing), and the concentration of lithium ion would be in a range from 1.0 μg·mL−1 to 5.0 μg·mL−1. 626



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Figure 3. Schematic of experimental apparatus for viscosity. Figure 2. Schematic of experimental apparatus for vapor pressure.

when it passed the bottom mark. The flow time of solution must be more than 200 s. Three repetitions were carried out for each absorbent concentration and temperature, and the results were averaged. The viscosities were determined by eq 2:

The average relative deviations obtained were 1.04 % (P ≤ 100 kPa) and 2.66 % (P > 100 kPa). Density measurements were carried out by means of a capillary pycnometer.31 The experimental apparatus consisted of a SYP1003-H precision viscometer oil bath, a capillary pycnometer (50 mL) with a capillary diameter of about 1 mm and a BSA224S analytic balance (Sartorius, Germany). The pycnometer was carefully dried, weighed, and then filled with degassed water or absorbent solution and placed in the oil bath. After thermal equilibrium was reached, the pycnometer was then taken out from the bath and weighed again after being cleaned and dried. The internal volumes of the pycnometer were carefully calibrated with degassed water at the same temperatures using the accurate known densities. Because the evaporation of degassed water became apparent when the temperature was higher than 353.15 K, the internal volumes of the pycnometer were calibrated with the thermal cubic expansion coefficient of borosilicate glass (1.0·10−5·K−1). Experiments on densities of solutions were performed in three replicates for each absorbent concentration at each temperature, and the averages were obtained. The differences of density in repeat runs were smaller than 0.03 %. The validity of the calibration was tested by measuring the density of NaCl solution with the concentration of 10 wt % in the temperature range from 293.15 K to 353.15 K. The average relative deviation between the measured data and the data from reference was 0.07 %.30 Viscosities were measured by using Ubbelohde capillary viscometers with different fine capillaries (0.24 mm, 0.36 mm, 0.46 mm, 0.58 mm, and 0.73 mm) and viscosity constants. The schematic of experimental apparatus was shown in Figure 3. The viscometer was cleaned with pure water and dried with acetone at room temperature. The interior glass surface was kept clean during all measurements. The viscometer was placed vertically in the SYP1003-H precision viscometer oil bath, and an exactly specified amount (10 mL) of absorbent solution at various absorbent concentrations was added by a pipet. After thermal equilibrium was reached, the liquid was then allowed to flow through the capillary, and a stopwatch (an accuracy of 0.01 s) was started when the liquid passed the top mark and stopped

η = k·tm·ρ

(2)

where η (mPa·s) is the viscosity of LiNO3/H2O solution, k (mm2·s−2) is the viscosity constant, tm (s) is the mean time of three repetitions, and ρ (g·cm−3) is the density of LiNO3/H2O solution at the same concentration and temperature. The errors of the viscosity in repeat runs were smaller than 0.06 %. The capillary viscometers were calibrated in the factory and validated using water in a range of temperature from 293.15 K to 353.15 K, and the average relative deviation was 1.10 %.30 The specific heat capacity of the LiNO3/H2O binary system was measured by a differential scanning calorimeter (DSC-60, Shimadzu Co. Japan). Here the method of linear temperature increase was applied. The specific heat capacity of sample is a function of heat flux, defined as eq 3: Cp(T ) =

d H (T ) 1 · dT m −1

(3)

−1

where Cp(T) (J·g ·K ) is the specific heat capacity of sample, T (K) is the absolute temperature, dH(T) (J) is the heat flux which is seen as the function of absolute temperature, and m (g) is the mass of sample. Because it is difficult to accurately determine the absolute value of dH/dT in the actual measurement, the indirect measurement method was usually used. One set of aluminum pans were weighed in turn to select the ones whose weight differences between each other were less than 0.1 mg. About 10.0 mg of α-Al2O3 and LiNO3 solution with different concentrations was weighed by analytic balance and sealed in aluminum pans by a crimper. The baseline was adjusted with two empty aluminum pans. The temperature and heat were calibrated with an indium sheet, and the relative deviations were 0.06 % and 0.7 %, respectively. After calibration, two empty aluminum pans were put into the sample slot and reference slot, and a baseline was obtained. The DSC curves of the standard material of α-Al2O3 and the sample were measured under the same conditions. Then the specific heat capacity Cp(T) at any temperature could be calculated by eq 4.32 627


Journal of Chemical & Engineering Data Cp(T ) =

mstd DSCs − DSC bl · ·Cp ,std ms DSCstd − DSC bl

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Table 1. Experimental Mass Fraction Solubilities w of Lithium Nitrate in Water at Temperature T and Pressure p = 0.1 MPaa

(4)

where mstd (mg) and ms (mg) are the mass of α-Al2O3 and sample, DSCstd (mW), DSCs (mW), and DSCbl (mW) are the DSC signals of α-Al2O3, sample and blank at temperature T, Cp,std (J·g−1·K−1) is the specific heat capacity of α-Al2O3 at temperature T. The schematic of DSC curves for specific heat capacity was given in Figure 4. Experiments on specific heat

T/K

w/%

T/K

w/%

277.15 283.15 293.15 298.15 303.15b 313.15 325.15

34.45 37.00 42.64 46.47 61.40 62.33 63.72

335.15 343.15 358.15 377.15 391.15 411.15 431.15

64.80 65.67 67.88 69.45 71.79 74.99 78.07

Standard uncertainties u are u(T) = ± 0.05 K and u(p) = ± 3.0 kPa, and the combined expanded uncertainty Uc is Uc(w) = ± 0.4 wt %. b Transition point of equilibrium solid phase. a

4

100w =

∑ Ai(T /K)i

(5)

i=0

where w (wt %) is the solubilities of LiNO3/H2O binary system, T (K) is the absolute temperature, and Ai are the regression parameters. The parameters were determined by a least-squares method, and the results are listed in Table 2. The Table 2. Values of Ai and AARD for Least-Squares Representation by eq 5

Figure 4. Schematic of DSC curves for specific heat capacity.

277.15 K ≤ T ≤ 303.15 K

i

capacity were carried out in three replicates for each LiNO3 concentration, and the results were averaged. The differences of the data in repeat runs were smaller than 2 %. The water and NaCl solution with a concentration of 10 wt % were used to validate the technique in a temperature range from 303.15 K to 343.15 K. The results were compared to those data from the reference, and the average relative deviations obtained were 1.44 % and 1.16 %.30 For the solubility, density, and viscosity measurements, the temperatures were obtained by the thermometer placed inside the precision viscometer oil bath, and the standard uncertainty of the temperature was ± 0.05 K. The temperature in vapor pressure measurement was determined by Pt-100 thermometer, and the standard uncertainty was ± 0.1 K. The temperature in specific heat capacity measurement was determined by DSC with an accuracy of ± 0.01 K. The solution prepared for vaporpressure measurement was weighed on a Mettler balance (PL2002) with a precision of ± 0.01 g. The reagents for solubility, density, viscosity, and specific heat capacity measurement were weighed on a Sartorius balance (BSA224S) with a precision of ± 0.1 mg. The uncertainties of the pipettes (10 mL, 20 mL, and 30 mL) used in solubility measurement are ± 0.05 mL. The combined standard uncertainties of solubility, density, viscosity, and specific heat capacity were estimated to ± 0.4 wt %, ± 0.001 g·cm−3, ± 0.02 mPa·s, and ± 0.06 J·g−1·K−1, respectively. The uncertainties of vapor pressure measured with a precision digital absolute pressure meter and vacuum pressure gauge were less than ± 1.2 % and ± 3.0 %, respectively.

A0 A1 A2 A3 A4

6

2.671645079·10 −3.71675517·104 1.93855482·102 −0.449270367 3.903675267·10−4

303.15 K < T ≤ 431.15 K

AARD

−1.096103·10 12.287189 −0.0491037 8.724015·10−5 −5.751717·10−8

0.13 %

3

overall average absolute relative deviation between experimental and calculated values was determined to be 0.13 % from eq 6. N

AARD = 1/N ∑ |(wexp − wcal)/wexp| i=1

(6)

where N is the number of points, wexp is the experimental value, and wcal is the calculated value. The experimental data and calculated results are plotted in Figure 5 and compared with the data reported in the literature. The data measured in this paper are in good agreement with the data reported by Campell and Bailey13 and Zeng et al.,14 and the AARD between the data

3. RESULTS AND DISCUSSION 3.1. Solubility. Solubilities of LiNO3/H2O binary system were measured in the range of temperature from 277.15 K to 431.15 K. The experimental data are given in Table 1. Polynomial eq 5 for solubilities of the LiNO3/H2O binary system is obtained as a function of absolute temperature from the experimental data.33

Figure 5. Plot of solubilities of LiNO3/H2O binary system: ◆, this paper; , calculated values; □, Donnan and Burt;10 △, International Critical Tables;12 ○, Campbell and Bailey;13 ◇, Zeng et al.14. 628



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Table 3. Experimental Data for Temperature T, Pressure p, and Mass Fraction w for the System Lithium Nitrate (1) + Water (2)a w1/(wt %) 50 %

55 %

60 %

65 %

70 %

P/kPa at T/K T P T P T P T P T P T P T P T P T P T P T P T P T P

297.6 1.172 383.1 65.873 435.6 290.0 297.9 0.930 362.4 26.074 435.7 240.8 303.0 1.077 394.0 62.22 447.8 277.1 333.0 4.544 425.2 128.2 383.1 28.035 454.1 204.5

303.2 1.699 388.4 77.492 441.2 332.5 302.1 1.107 374.0 39.407 440.7 280.0 308.0 1.516 401.7 79.414 452.3 307.0 342.8 6.995 434.1 165.0 393.5 39.958 458.6 230.0

307.6 2.324 393.0 90.801 446.8 387.5 308.5 1.792 383.1 55.389 445.5 321.0 313.1 1.85 407.8 95.628 457.3 352.5 352.5 11.18 443.7 207.5 403.1 54.169 462.7 250.0

312.6 3.196 396.4 98.012 452.5 445.0 312.7 2.475 391.9 70.976 450.6 365.0 323.0 3.42 414.1 110.0 462.7 402.0 363.3 17.975 448.6 232.5 413.0 72.807 467.1 280.0

323.0 5.35 402.4 111.8 458.4 520.0 318.2 3.444 398.7 87.59 455.2 408.0 333.0 5.842 419.3 131.0 467.7 455.0 374.1 25.332 453.7 267.5 422.7 96.133 473.8 325.0

333.2 8.775 409.0 137.0 463.4 580.0 323.5 4.547 402.7 97.504 461.4 480.0 343.0 9.497 423.9 147.0 472.7 508.0 383.1 34.484 458.7 305.0 428.9 107.0

342.9 13.823 415.1 165.0 467.6 640.0 328.2 5.909 410.1 122.7 466.4 537.5 352.8 14.639 429.5 171.5

353.1 22.148 420.5 191.0 471.8 700.0 333.1 7.502 416.8 144.2 472.4 620.0 363.6 22.8 434.9 200.5

393.6 48.816 463.8 345.0 433.8 122.5

403.7 66.787 468.7 385.0 439.2 142.5

363.6 34.282 426.5 228.0

372.1 46.446 428.0 238.0

343.0 11.933 426.2 185.5

353.2 18.144 431.3 213.5

373.4 31.631 439.2 224.5

383.5 44.24 441.8 241.2

412.7 89.297 473.1 428.0 443.8 160.0

418.1 104.53

449.7 182.0

Standard uncertainties u are u(T) = ± 0.1 K and u(w1) = ± 0.2 wt %, and the relative standard uncertainties ur are ur(p) = ± 1.2 % (p ≤ 100 kPa) and ur(p) = ± 3.0 % (p > 100 kPa). a

Table 4. Values of Ai, Bi, and Ci and AARD for Least-Squares Representation by eq 7

calculated by eq 5 and the data from the two literatures are 0.92 % and 0.78 %, respectively. Some points in the temperature range from 298.15 K to 303.15 K are inconsistent with the data measured by Donnan and Burt10 and listed in the International Critical Tables.12 It is mainly because that LiNO3 solution may be metastable due to a big supercooling degree at the temperature near 303.15 K. The correlation for LiNO3 solubility was provided by Eysseltová and Orlova.15 The AARD between the data calculated by eq 5 and the data calculated in their article is 0.98 %. The solubilities in this paper are in good agreement with most literature data at the temperature up to 431.15 K. The solubility of LiNO3/H2O binary system increases significantly at the temperature of about 303.15 K and becomes almost equal to that of LiBr/H2O from literature when the temperature is higher than 303.15 K.34 3.2. Vapor Pressure. Vapor pressures of LiNO3/H2O binary system were measured in the temperature range from 297.65 K to 473.85 K and in the mass fraction range from 50 wt % to 70 wt %. The experimental data are shown in Table 3. The experimental vapor pressure results of LiNO3/H2O binary system are fitted to the Antoine eq 7.33,35,36

i 0 1 2 3 4

Ai

Bi

Ci

6.148192 −0.313104 0.173883 −7.119462·10−4 5.104596·10−7

−1.229085·10 2.959166·102 −1.650989·103 2.194534 −4.193150·10−4 3

AARD 2

1.252132·10 −3.511392·102 −8.934301·103 −2.515973·103 −1.854562·102

0.14 %

4

log(P /kPa) =

∑ [Ai + {Bi /(T − Ci)}](100w)i i=0

(7)

Figure 6. Plot of vapor pressures of LiNO3/H2O binary system (P ≤ 100 kPa): ◆, 50 wt %; ■, 55 wt %; ▲, 60 wt %; ●, 65 wt %; ∗, 70 wt %; , calculated values; ◇, 49.5 wt %, Patil et al.;5 □, 50 wt %, ○, 65 wt %, Campbell et al.16

where P (kPa) is the vapor pressure of LiNO3/H2O binary system, Ai, Bi, and Ci are the regression parameters, T (K) is the absolute temperature, and w (%) is the mass fraction of LiNO3. The values of AARD and Ai, Bi, and Ci are listed in Table 4. The experimental data and calculated results are plotted in Figure 6 629



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(P ≤ 100 kPa) and Figure 7 (P > 100 kPa) and compared with the data in literature. Figure 6 shows that the experimental data

function of absolute temperature and mass concentration by a least-squares method from the experimental data.31,33,37,38 3

(ρ /g·cm−3) =

∑ [(Ai + Bi T + CiT 2)wi]

(8)

i=0 −3

where ρ (g·cm ) is the density of the LiNO3/H2O binary system, T (K) is the absolute temperature, w (%) is the mass fraction of LiNO3, and Ai, Bi, and Ci are the regression parameters. The values of AARD and Ai, Bi, and Ci are given in Table 6. The experimental and calculated data are plotted in Table 6. Values of Ai, Bi, and Ci and AARD for eq 8

Figure 7. Plot of vapor pressures of LiNO3/H2O binary system (P > 100 kPa): ◆, 50 wt %; ■, 55 wt %; ▲, 60 wt %; ●, 65 wt %; ∗, 70 wt %; , calculated values.

in this paper are in good agreement with the data reported by Patil et al.5 and Campell et al.16 except for some points. The AARD between the data calculated by eq 7 and the experimental data from the two literatures are 4.04 % and 3.95 %. The vapor pressure data are also fitted to Antoine type of equation by Patil et al.,5 and the available range of the mass concentration is from 9.874 wt % to 54.840 wt %. The data calculated by eq 7 is compared with the data calculated by the equation of Patil et al.,5 and the AARD is 3.43 %. The other vapor pressure data reported in literature have no great significance for us, because they are mainly measured at a mass concentration less than 50 wt %.17−21 The vapor pressure of LiNO3/H2O binary system is also compared with that of LiBr solution from literature, and the former was larger than the latter at the same temperature and mass concentration.34 3.3. Density. Densities of LiNO3/H2O binary system were measured in the ranges of temperature and mass fraction from 283.15 K to 413.15 K and from 30 % to 65 %. The experimental data are shown in Table 5. The polynomial eq 8 for densities of LiNO3/H2O binary system is obtained as a

i

Ai

Bi

Ci

AARD

0 1 2 3

1.893299·10−2 5.140507 −3.832563 −0.767904

9.240495·10−3 −4.678622·10−2 6.712131·10−2 −2.473169·10−2

−1.945296·10−5 1.020831·10−4 −1.722026·10−4 8.851732·10−5

0.11 %

Figure 8. Plot of densities of LiNO3 /H2O binary system: ◆, 30 wt %; ■, 35 wt %; ●, 40 wt %; ▲, 45 wt %; ◇, 50 wt %; □, 55 wt %; ○, 60 wt %; △, 65 wt %; , calculated values; ×, 30 wt %, ∗, 35 wt %, +, 40 wt %, International Critical Tables.27

Table 5. Experimental Data of Densities ρ for the System Lithium Nitrate (1) + Water (2) at Mass Fraction w and Pressure p = 0.1 MPaa ρ/(g·cm−3) at T/K

w1/(wt %) 30 % 35 % 40 % 45 % 50 % 55 % 60 % 65 %

T ρ T ρ T ρ T ρ T ρ T ρ T ρ T ρ

283.15 1.203 293.15 1.236 293.15 1.274 303.15 1.314 303.15 1.358 303.15 1.405 313.15 1.449 333.15 1.494

293.15 1.199 303.15 1.231 303.15 1.269 313.15 1.307 313.15 1.352 313.15 1.398 323.15 1.440 343.15 1.486

303.15 1.193 313.15 1.225 313.15 1.263 323.15 1.300 323.15 1.346 323.15 1.391 333.15 1.432 353.15 1.479

313.15 1.188 323.15 1.216 323.15 1.257 333.15 1.293 333.15 1.339 333.15 1.384 343.15 1.424 363.15 1.472

323.15 1.179 333.15 1.210 333.15 1.250 343.15 1.286 343.15 1.331 343.15 1.376 353.15 1.416 373.15 1.464

333.15 1.173 343.15 1.203 343.15 1.243 353.15 1.279 353.15 1.324 353.15 1.369 363.15 1.408 383.15 1.456

343.15 1.166 353.15 1.196 353.15 1.236 363.15 1.272 363.15 1.317 363.15 1.361 373.15 1.400 393.15 1.448

353.15 1.159 363.15 1.189 363.15 1.230 373.15 1.265 373.15 1.309 373.15 1.353 383.15 1.393 403.15 1.440

363.15 1.152 373.15 1.181 373.15 1.222 383.15 1.258 383.15 1.301 383.15 1.346 393.15 1.385 413.15 1.430

373.15 1.144

383.15 1.213

393.15 1.294 393.15 1.338 403.15 1.377

Standard uncertainties u are u(T) = ± 0.05 K, u(w1) = ± 0.1 wt % and u(p) = ± 3.0 kPa, and the combined expanded uncertainty Uc is Uc(ρ) = ± 0.001 g·cm−3. a

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Article

Table 7. Experimental Data of Viscosities η for the System Lithium Nitrate (1) + Water (2) at Mass Fraction w and Pressure p = 0.1 MPaa η/(mPa·s) at T/K

w1/(wt %) T η T η T η T η T η T η T η T η

30 % 35 % 40 % 45 % 50 % 55 % 60 % 65 %

283.15 2.410 293.15 2.241 293.15 2.791 303.15 2.870 303.15 3.839 303.15 5.357 313.15 6.274 333.15 5.721

293.15 1.902 303.15 1.850 303.15 2.240 313.15 2.363 313.15 3.114 313.15 4.299 323.15 4.961 343.15 4.764

303.15 1.535 313.15 1.552 313.15 1.888 323.15 1.994 323.15 2.543 323.15 3.515 333.15 4.153 353.15 4.020

313.15 1.300 323.15 1.306 323.15 1.580 333.15 1.700 333.15 2.143 333.15 2.926 343.15 3.472 363.15 3.394

323.15 1.112 333.15 1.134 333.15 1.356 343.15 1.479 343.15 1.854 343.15 2.493 353.15 2.955 373.15 2.953

333.15 0.950 343.15 0.985 343.15 1.182 353.15 1.302 353.15 1.616 353.15 2.158 363.15 2.564 383.15 2.615

343.15 0.826 353.15 0.864 353.15 1.041 363.15 1.149 363.15 1.466 363.15 1.882 373.15 2.248 393.15 2.307

353.15 0.731 363.15 0.773 363.15 0.927 373.15 1.034 373.15 1.306 373.15 1.693 383.15 1.993 403.15 2.095

363.15 0.650 373.15 0.700 373.15 0.837 383.15 0.938 383.15 1.175 383.15 1.505 393.15 1.785 413.15 1.923

373.15 0.586

383.15 0.763

393.15 1.371 403.15 1.625

Standard uncertainties u are u(T) = ± 0.05 K, u(w1) = ± 0.1 wt %, and u(p) = ± 3.0 kPa, and the combined expanded uncertainty Uc is Uc(η) = ± 0.02 mPa·s. a

Figure 8 and compared with the data reported in literature. As shown in Figure 8, the measurement results obtained are in good agreement with the data from International Critical Tables.27 The AARD between the data calculated by eq 8 and experimental data reported by Campbell et al.,22 Wimby and Berntsson,23 and International Critical Tables27 are 0.53 %, 0.25 %, and 0.30 %, respectively. There are two correlating equations provided by Wimby and Berntsson23 and Puchkov and Matashkin.39 The AARD between the data calculated by eq 8 and the two equations are 0.53 % and 0.71 %. Results show that the experimental data in this paper agree well with the literature data. The density of LiNO3/H2O binary system is smaller than that of LiBr/H2O from the literature at the same temperature and mass concentration.34 3.4. Viscosity. Viscosities of LiNO3/H2O binary system were measured in the temperature range from 283.15 K to 413.15 K and in the mass fraction range from 30 % to 65 %. The experimental data are shown in Table 7.The experimental data are fitted to polynomial eq 9 as a function of absolute temperature and mass concentration by a least-squares method:33

Figure 9. Plot of viscosities of the LiNO3/H2O binary system: ◆, 30 wt %; ■, 35 wt %; ●, 40 wt %; ▲, 45 wt %; ◇, 50 wt %; □, 55 wt %; ○, 60 wt %; △, 65 wt %; , calculated values.

calculated by eq 9 are in good agreement with the data reported by Wimby and Berntsson23 and Popević and Nedeljković,40 and the AARD are 1.98 % and 3.95 %, respectively. But there are some inconsistencies between our data and the data measured by Campbell et al.22 at temperature 298.15 K and 383.15 K.22 The correlation equations are given in the literature of Popević and Nedeljković40 and Aseyev.41 We compared the value calculated by eq 9 and their equations. Results show that the viscosity obtained by eq 9 agrees well with the data by equation of Popević and Nedeljković,40 and the AARD is 3.66 %. We also find that the data calculated by eq 9 and the equation of Aseyev are inconsistent, but the data in this paper are in good agreement with most literature data. The viscosity of LiNO3/ H2O binary system is larger than that of LiBr/H2O from literature at the same temperature and concentration, but the difference became smaller with the increase of temperature and concentration.34 3.5. Specific Heat Capacity. Specific heat capacities of LiNO3/H2O binary system were measured in the temperature range from 303.15 K to 373.15 K and in the mass fraction range

4

log(η /mPa·s) =

∑ [(Ai + Bi /T + Ci/T 2)wi] i=0

(9)

where η (mPa·s) is the viscosity of LiNO3/H2O binary system, T (K) is the absolute temperature, w (%) is the mass fraction of LiNO3, Ai, Bi, Ci are the coefficients in eq 9. The values of AARD and Ai, Bi, and Ci are given in Table 8. The experimental data and calculated results are plotted in Figure 9, and compared with those data of literatures. It is found that the data Table 8. Values of Ai, Bi, and Ci and AARD for eq 9 i

Ai

Bi

Ci

AARD

0 1 2 3 4

−3.287149 14.441569 −34.959255 48.831843 −24.464483

2.348873·102 −2.119397·102 −3.896473·103 6.178260·103 −4.956081·103

1.389774·105 −3.878089·105 1.549470·106 −1.843624·106 1.420491·106

0.14 %

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Table 9. Experimental Data of Specific Heat Capacities Cp for the System Lithium Nitrate (1) + Water (2) at Mass Fraction w and Pressure p = 0.1 MPaa Cp/(J·g−1·K−1) at T/K

w1/(wt %) T Cp T Cp T Cp T Cp T Cp T Cp T Cp

30 % 35 % 40 % 45 % 50 % 55 % 60 %

303.15 3.434 303.15 3.243 303.15 3.084 303.15 2.998 303.15 2.871 303.15 2.757 313.15 2.659

313.15 3.457 313.15 3.274 313.15 3.115 313.15 3.020 313.15 2.894 313.15 2.784 323.15 2.667

323.15 3.483 323.15 3.313 323.15 3.145 323.15 3.031 323.15 2.924 323.15 2.792 333.15 2.685

333.15 3.511 333.15 3.341 333.15 3.182 333.15 3.047 333.15 2.931 333.15 2.790 343.15 2.691

343.15 3.525 343.15 3.365 343.15 3.200 343.15 3.065 343.15 2.943 343.15 2.807 353.15 2.712

353.15 3.555 353.15 3.386 353.15 3.231 353.15 3.102 353.15 2.960 353.15 2.840 363.15 2.733

363.15 3.573 363.15 3.413 363.15 3.257 363.15 3.149 363.15 3.005 363.15 2.877 373.15 2.770

373.15 3.291 373.15 3.191 373.15 3.033 373.15 2.903

a Standard uncertainties u are u(T) = ± 0.01 K, u(w1) = ± 0.1 wt %, and u(p) = ± 3.0 kPa, and the combined expanded uncertainty Uc is Uc(Cp) = ± 0.06 J·g−1·K−1.

in lower ranges of temperature and concentration, there are no overlapped data for comparison. The specific heat capacity of LiNO3/H2O binary system is larger than that of LiBr/H2O from literature at the same temperature and concentration.34

from 30 % to 60 %. The experimental data are shown in Table 9.The experimental data are fitted to the following eq 10.42,43 3

(Cp/J·g −1·K−1) =

∑ [(Ai + Bi T + CiT 2)wi]

(10)

i=0 −1

4. CONCLUSIONS The solubility, vapor pressure, density, viscosity, and specific heat capacity of the LiNO3/H2O binary system were measured systematically at relatively wide ranges of temperature and mass fraction. Regression equations for measurement data with high accuracy were obtained by a least-squares method. This work will be helpful for design and evaluation of the absorption heat pump using LiNO3/H2O as a working fluid.

−1

where Cp (J·g ·K ) is the specific heat capacity of LiNO3/ H2O binary system, T (K) is the absolute temperature, w (%) is the mass fraction of LiNO3, and Ai, Bi, and Ci are the regression parameters. The values of AARD and Ai, Bi, and Ci are given in Table 10. The experimental and calculated results of specific Table 10. Values of Ai, Bi, and Ci and AARD for eq 10 i

Ai

Bi

Ci

AARD

0 1 2 3

49.233488 −3.702743·102 9.200733·102 −7.147231·102

−0.240441 1.991511 −5.062520 3.977363

3.273571·10−4 −2.732184·10−3 7.037091·10−3 −5.582135·10−3

0.23 %

■

AUTHOR INFORMATION

Corresponding Author

*Tel.: +86 10 62333542; fax: +86 10 62333542. E-mail address: [email protected]. Funding

The authors gratefully acknowledge financial support from the National 863 Plan Project of China (No.: 2008AA050403) and the key project of the Ministry of Education & Guangdong Province (No.: 2009A090100032).

heat capacity are plotted in Figure 10. It shows that the specific heat capacity of LiNO3/H2O binary system increases with increasing temperature and decreases with increasing concentration. Because the data reported in literatures were measured

Notes

The authors declare no competing financial interest.

■

REFERENCES

(1) Keil, C.; Plura, S.; Radspieler, M.; Schweigler, C. Application of Customized Absorption Heat Pumps for Utilization of Low-grade Heat Sources. Appl. Therm. Eng. 2008, 28, 2070−2076. (2) Li, Y.; Fu, L. A New Type of District Heating System Based on Distributed Absorption Heat Pumps. Energy 2011, 36, 4570−4576. (3) Grover, G. S.; Devotta, S. Performance of an Experimental Absorption Cooler Using Aqueous LiCl and LiCl/LiBr Solutions. Ind. Eng. Chem. Res. 1989, 28, 250−253. (4) Iyoki, S. Solubilities for the Two Ternary Systems Water + Lithium Bromide + Lithium Iodide and Water + Lithium Chloride + Lithium Nitrate at Various Temperatures. J. Chem. Eng. Data 1993, 38, 396−398. (5) Patil, K. R.; Chaudharl, S. K.; Katti, S. S. Thermodynamic Properties of Aqueous Electrolyte Solutions. 3. Vapor Pressure of Aqueous Solutions of LiNO3, LiCl + LiNO3, and LiBr + LiNO3. J. Chem. Eng. Data 1992, 37, 136−138.

Figure 10. Plot of specific heat capacity of LiNO3/H2O binary system: ◆, 30 wt %; ■, 35 wt %; ●, 40 wt %; ▲, 45 wt %; ◇, 50 wt %; □, 55 wt %; ○, 60 wt %; , calculated values. 632



Article

(27) Washburn, E. W. International Critical Tables of Numerical Data Physics, Chemistry and Technology, Vol. 3; McGraw-Hill Book Co. Inc.: New York, 1928; pp 76−78. (28) Washburn, E. W. International Critical Tables of Numerical Data Physics, Chemistry and Technology, Vol. 5; McGraw-Hill Book Co. Inc.: New York, 1929; p 15. (29) Washburn, E. W. International Critical Tables of Numerical Data Physics, Chemistry and Technology, Vol. 5; McGraw-Hill Book Co. Inc.: New York, 1929; p 122. (30) Liu, G. Q.; Ma, L. X.; Liu, J. Handbook of Chemical and Engineering Property Data, Inorganic Volume; Chemical Industry Press: Beijing, 2006. (31) Iyoki, S.; Iwasaki, S.; Kuriyama, Y.; Uemura, T. Densities, Viscosities, and Surface Tensions for the Two Ternary Systems H2O + LiBr + LiI and H2O + LiCl + LiNO3. J. Chem. Eng. Data 1993, 38, 302−305. (32) McHugh, J.; Fideu, P.; Herrmann, A.; Stark, W. Determination and Review of Specific Heat Capacity Measurements During Isothermal Cure of an Epoxy Using TM-DSC and Standard DSC Techniques. Polym. Test. 2010, 29, 759−765. (33) Park, Y.; Kim, J. S.; Lee, H. Density, Vapor Pressure, Solubility, and Viscosity for Water+Lithium Bromide+Lithium Nitrate+1, 3Propanediol. J. Chem. Eng. Data 1997, 42, 145−148. (34) Chen, D.; Xie, J. H. The Technology and Application of Heat Pump; Chemical Industry Press: Beijing, 2008. (35) Safarov, J. T. Vapor Pressure of Heat Transfer Fluids of Absorption Refrigeration Machines and Heat Pumps: Binary Solutions of Lithium Nitrate with Methanol. J. Chem. Thermodyn. 2005, 37, 1261−1267. (36) Verevkin, S.; Safarov, J.; Bich, E.; Hassel, E.; Heintz, A. Study of Vapor Pressure of Lithium Nitrate Solutions in Ethanol. J. Chem. Thermodyn. 2006, 38, 611−616. (37) Kim, J. S.; Lee, H. Solubilities, Vapor Pressure, Densities, and Viscosities of the LiBr + LiI + HO(CH2)3OH + H2O System. J. Chem. Eng. Data 2001, 46, 79−83. (38) Gierszewski, P. J.; Prasad, R. C.; Kirk, D. W. Properties of LiOH and LiNO3 Aqueous Solutions: Additional Results. Fusion Eng. Des. 1992, 15, 279−283. (39) Puchkov, L. V.; Matashkin, V. G. Density of Aqueous Lithium Nitrate Solutions at High Temperatures in the Range of 25−300 °C. Russ. J. Appl. Chem. 1970, 43, 1864−1867. (40) Popević, J.; Nedeljković, L. J. Viskosimetrische Untersuchung des Systems LiNO3-H2O. Monatsh. Chem. 1968, 99, 1971−1975. (41) Aseyev, G. G. Electrolytes. Properties of Solutions. Methods for Calculation of Multicomponent Systems and Experimental Data on Thermal Conductivity and Surface Tension; Begell-House Inc.: New York, 1988. (42) Salavera, D.; Esteve, X.; Patil, K. R.; Mainar, A. M.; Coronas, A. Solubilitym Heat Capacity, and Density of Lithium Bromide + Lithium Iodide + Lithium Nitrate + Lithium Chloride Aqueous Solutions at Several Compositions and Temperatures. J. Chem. Eng. Data 2004, 49, 613−619. (43) He, Z. B.; Zhao, Z. Ch.; Zhang, X. D.; Feng, H. Thermodymic Properties of New Heat Pump Working Pairs: 1,3-Dimethylimidazolium Dimethylphosphate and Water, Ethanol and Methanol. Fluid Phase Equilib. 2010, 298, 83−91.

(6) Stephan, K.; Schmitt, M.; Hebecker, D.; Bergmann, T. Dynamics of a Heat Transformer Working with the Mixture NaOH-H2O. Int. J. Refrig. 1997, 20, 483−495. (7) Romero, R. J.; Rivera, W.; Gracia, J.; Best, R. Theoretical Comparison of Performance of an Absorption Heat Pump System for Cooling and Heating Operating with an Aqueous Ternary Hydroxide and Water/Lithium Bromide. Appl. Therm. Eng. 2001, 21, 1137−1147. (8) Yoon, J. I.; Kwon, O. K.; Moon, C. G.; Lee, H. S.; Bansal, P. Heat and Mass Transfer Characteristics of a Helical Absorber Using LiBr and LiBr + LiI + LiNO3 + LiCl Solutions. Int. J. Heat Mass Transfer 2005, 48, 2102−2109. (9) Sun, J.; Fu, L.; Zhang, S. G. A Review of Working Fluids of Absorption Cycles. Renewable Sustainable Energy Rev. 2012, 16, 1899− 1906. (10) Donnan, F. G.; Burt, B. C. The Solubilities and TransitionPoints of Lithium Nitrate and Its Hydrates. J. Chem. Soc. Trans. 1903, 83, 335−342. (11) Seidell, A. Solubilities of Inorganic and Metal Organic Compounds, Vol. 1; D. Van Nostrand Co. Inc.: New York, 1953; pp 1953−927. (12) Washburn, E. W. International Critical Tables of Numerical Data Physics, Chemistry and Technology, Vol. 4; McGraw-Hill Book Co. Inc.: New York, 1928; pp 233−234. (13) Campbell, A. N.; Bailey, R. A. The System Lithium NitrateEthanol-Water and Its Component Binary System. Can. J. Chem. 1958, 36, 518−536. (14) Zeng, D. W.; Ming, J. W.; Voigt, W. Thermodynamic Study of the System (LiCl + LiNO3 + H2O). J. Chem. Thermodyn. 2008, 40, 232−239. (15) Eysseltová, J.; Orlova, V. T. IUPAC-NIST Solution Data Series. 89. Alkali Metal Nitrates. Part1. Lithium Nitrate. J. Phys. Chem. Ref. Data 2010, 39 (033104), 1−39. (16) Campbell, A. N.; Fishman, J. B.; Rutherford, G.; Chaefer, T. P.; Ross, L. Vapor Pressure of Aqueous Solutions of Silver Nitrate, of Ammonium Nitrate, and of Lithium Nitrate. Can. J. Chem. 1956, 34, 151−159. (17) Sacchetto, G. A.; Bombi, G. G.; Maccà, C. Vapor Pressure of Very Concentrated Electrolyte Solutions 1. Measurements on {(1-x) H2O + xLiNO3} and {(1-x) H2O + xNH4NO3} by a Dew-Point Apparatus. J. Chem. Thermodyn. 1981, 13, 31−40. (18) Abdulagatov, I. M.; Azizov, N. D. Experimental Vapor Pressure and Derived Thermodynamic Properties of Aqueous Solutions of Lithium Nitrate from 423 to 623 K. J. Solution Chem. 2004, 33, 1517− 1537. (19) Pearce, J. N.; Nelson, A. F. The Vapor Pressures of Aqueous Solutions of Lithium Nitrate and the Activity Coefficients of Some Alkali Salts in Solutions of High Concentration at 25 °C. J. Am. Chem. Soc. 1932, 54, 3544−3555. (20) Puchkov, L. V.; Matashkin, V. G. Vapor Pressure and Some Thermodynamics Functions of Aqueous Solutions of LiNO3 and NaNO3 at Temperature 150−300 °C. Russ. J. Appl. Chem. 1970, 9, 1963−1966. (21) Washburn, E. W. International Critical Tables of Numerical Data Physics, Chemistry and Technology, Vol. 3; McGraw-Hill Book Co. Inc: New York, 1928; p 132. (22) Campbell, A. N.; Debus, G. H.; Kartzmark, E. M. Conductances of Aqueous Lithium Nitrate Solutions at 25.0 and 110 °C. Can. J. Chem. 1955, 33, 1508−1514. (23) Wimby, J. M.; Berntsson, T. S. Viscosity and Density of Aqueous Solutions of LiBr, LiCl, ZnBr2, CaCl2, and LiNO3. 1. Single Salt Solutions. J. Chem. Eng. Data 1994, 39, 68−72. (24) Roy, M. N.; Jha, A.; Choudhury, A. Densities, Viscosities and Adiabatic Compressibilities of Some Mineral Salts in Water at Different Temperatures. J. Chem. Eng. Data 2004, 49, 291−296. (25) Abdulagatov, I. M.; Azizov, N. D. (p, Vm, T, x) Measurements for Aqueous LiNO3 Solutions. J. Chem. Thermodyn. 2004, 36, 17−27. (26) Abdulagatov, I. M. Viscosities of Aqueous LiNO3 Solutions at Temperature from 298 to 573 K and at Pressures up to 30 MPa. Ind. Eng. Chem. Res. 2005, 44, 416−425. 633


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