Density Measurements of Unloaded and CO2-Loaded 3-Amino-1

Publication Date (Web): December 21, 2015 ... In the second part of this work, densities of CO2-loaded solutions were measured at 0.1 and 0.5 mass fra...
0 downloads 0 Views 974KB Size
Download PDF
Article pubs.acs.org/jced

Density Measurements of Unloaded and CO2‑Loaded 3‑Amino-1propanol Solutions at Temperatures (293.15 to 353.15) K Zulkifli Idris† and Dag A. Eimer*,†,‡ †

Faculty of Technology, Telemark University College, Kjølnes Ring 56, Porsgrunn 3918, Norway Tel-Tek, Kjølnes Ring 30, Porsgrunn 3918, Norway

‡

S Supporting Information *

ABSTRACT: The first part of this work presents experimental density data of aqueous 3-amino-1-propanol (3A1P) solutions at different compositions and temperatures of (293.15 to 353.15) K. It was found that densities decreased with increasing temperatures and were concentration dependent. Excess molar volumes of aqueous 3A1P were also established. Five different methods were compared for correlating density data of unloaded 3A1P solutions. In the second part of this work, densities of CO2-loaded solutions were measured at 0.1 and 0.5 mass fractions of 3A1P at increasing temperatures and CO2-loadings. Two different models were used to regress these experimental data. The suitability of these methods to represent densities of unloaded and CO2-loaded 3A1P solutions is evaluated.

1. INTRODUCTION Aqueous solutions of alkanolamines are well established absorbents employed to chemically absorb carbon dioxide (CO2) in industrial processes.1 Extensive studies have also been performed to identify potentially better absorbents, and several new amines have been proposed.2−4 Comprehensive studies on the physical and chemical properties of these new amines are necessary before they can be used industrially. Among important experimental data required are kinetic constants, CO2 solubility, densities, and viscosities.5 Density data are used for engineering calculations, and in a CO2-capture process the solutions are normally loaded with CO2. Figure 1 illustrates a schematic chemical structure of 3-amino1-propanol (3A1P) which is the subject of this study. The main

Table 1. Densities of Aqueous 3A1P Solutions As Reported in Literaturea source Kermanpour and Niakan12 Omrani et al.13 Á lvarez et al.14 Kermanpour et al.15 Herba et al.16 a

temp range, K

CO2 loaded

0.99

293.15 to 333.15

no

0.99 0.99 0.99 not stated

298.15 to 308.15 298.15 to 323.15 293.15 to 333.15 293.15

no no no no

As stated by the supplier.

of 3A1P solutions in literature. In this paper, new and more extensive density data of unloaded and CO2-loaded 3A1P solutions are reported. Accurate representation of experimental density data is essential for optimal design in chemical technology. As such, a number of techniques have been proposed to correlate experimental density data of unloaded aqueous amine solutions, and the one most commonly applied is based on the Redlich− Kister equation.17 Meanwhile, Weiland’s method is used to fit densities of CO2 loaded solutions.18 In this paper, five methods for correlating density data of unloaded solutions are evaluated. Furthermore, two methods for representing densities of carbonated 3A1P solutions are applied to the present data and compared.

Figure 1. Structure of 3-amino-1-propanol (3A1P).

difference between 3A1P and monoethanolamine (MEA) is the presence of an extra alkyl-group (−CH2). Computational studies on several amines performed by da Silva and Svendsen6 show that 3A1P has a high reaction rate toward CO2 which makes it suitable to deal with gas streams with low CO2 partial pressures. Alongside theoretical studies, the kinetics and solubility of CO2 in 3A1P solutions have been published by several research groups.7−11 Table 1 presents available experimental density data © 2015 American Chemical Society

mass fraction puritya

Received: May 12, 2015 Accepted: December 7, 2015 Published: December 21, 2015 173

DOI: 10.1021/acs.jced.5b00412 J. Chem. Eng. Data 2016, 61, 173−181

Journal of Chemical & Engineering Data

Article

2. EXPERIMENTAL SECTION 2.1. Materials. All chemicals used in this work were of analytical grade and used as received without any purification. The purity and source of the chemicals are given in Table 2.

The combined standard uncertainty for CO2-loaded 3A1P solutions is 2.16 kg·m−3, taking into consideration similar factors as discussed earlier plus the contribution from uncertainty in CO2-loading values. The uncertainty due to CO2-loading values was calculated according to our previous publication.22 A value of Uc(ρ) = 4.32 kg·m−3 is quoted as the combined expanded uncertainty at 95% confidence level. To quantitatively evaluate deviations between models studied and experimental data in this work, we calculated average and maximum absolute deviations (AAD and AMD) according to the formulas given in eqs 1 and 2. In both cases N, ρEi and ρCi refer to the number of data available, density value obtained from the experimental work, and density value calculated from the model, respectively.

Table 2. Chemicals Information Tablea chemical name 3-amino-1-propanol (3A1P) carbon dioxide (CO2) a

mole fraction puritya

source

purification

≥ 0.99

Sigma Aldrich

no

0.9999

AGA Norge AS

no

As stated by the supplier.

AAD (kg·m−3) =

Solutions were gravimetrically prepared using degassed Milli-Q water (the water purification instrument was purchased from Millipore Corporation. Resistivity, 18.2 MΩ.cm). 2.2. Apparatus and Procedure. Samples of 3A1P at different compositions ranging from 0.1 to 1.0 mass fractions were weighed using a precision balance (Mettler Toledo XS-403S, standard uncertainty 1 × 10−4 g). As discussed in our previous publication,19 approximately 1−2 g of aqueous 3A1P was titrated using 1 mol·L−1 HCl to an equivalence point to determine the actual mass fraction of 3A1P. On the basis of our experiments, we found that the difference between the mass fractions from routine sample preparation and titration could be considered as negligible (the calculated average mass fraction deviation between these two techniques was 0.001). The CO2-loaded solutions were prepared by bubbling volumetrically measured CO2 into aqueous 3A1P solutions. The resulting aqueous CO2-loaded amine solutions were analyzed using an acid−base titration method to determine the accurate CO2-loadings according to previous publications.11,20 Densities of 3A1P solutions with and without CO2 loadings were measured using a digital density meter from Anton Paar (DMA 4500). Routine calibrations with degassed Milli-Q water at a temperature of 293.15 K were performed before and after density measurements. The density data of water were compared with reference data from Bettin and Spieweck (Table S1).21 An average experimental standard deviation of 0.04 kg·m−3 was obtained. This value is smaller than the instrument standard uncertainty quoted by the manufacturer (0.05 kg·m−3), suggesting that our instrument is functioning properly. It should also be noted that all experiments in this work were performed at atmospheric pressure.

1 N

N

∑ |ρi E − ρiC | i=1

AMD (kg·m−3) = |ρi E − ρiC |

(1) (2)

4. RESULTS, DATA REGRESSION, AND DISCUSSION 4.1. Densities of H2O (1) and 3A1P (2) Solutions. In this work, densities of unloaded aqueous 3A1P solutions were examined at different mass fractions and temperatures, and results are tabulated in Table 3. Densities of pure 3A1P are compared with literature values in Figure 2. As can be seen, our experimental data agree reasonably well with the reported density data, albeit there being minimal systematic deviation with the data of Alvarez et al.14 The average absolute deviations between our experimental data and those of Kermanpour et al.,15 Kermanpour and Niakan,12 Herba et al.,16 and Alvarez et al.14 are (0.2, 0.1, 1.0 and 3.5) kg·m−3, respectively. The low deviations indicate that these measurements are reliable. Figure 3 displays plots of densities against mass fractions of 3A1P at different temperatures. The density curves increase as the mass fractions of 3A1P increase, and a maximum value is recorded at around 0.6 mass fraction for temperatures between (293.15 and 338.15) K. At temperatures higher than 338.15 K, densities decrease with increasing mass fractions. It is also apparent that densities decrease as temperatures increase, as expected. The densities of pure 3A1P are found to be lower than densities of water at all temperatures studied in this work. In this section, five different techniques for estimating densities of unloaded alkanolamines are explored. First, the Redlich− Kister equation as shown in eq 3 correlates the excess molar volumes VEm, as a function of composition xi.17 i=n

3. ASSESSMENT OF EXPERIMENTAL UNCERTAINTIES According to the manufacturer, there are two uncertainties associated with the DMA 4500 density meter: The given standard uncertainty for temperature is 0.03 K, and instrument density standard uncertainty is 0.05 kg.m−3. In the case of unloaded aqueous 3A1P solutions, a standard uncertainty of 0.025 kg·m−3 with respect to temperature was calculated, based on the change of densities against temperatures of 0.82 kg·m−3.K−1. The uncertainty of the mass fraction can be estimated from the purity of 3A1P, and the value is 0.01. The combined standard uncertainty can then be calculated using a root-sum of squares formula of the uncertainty factors and the value obtained is 1.41 kg·m−3. Therefore, at 95% confidence level (coverage factor k equals 2), the combined expanded uncertainty is Uc(ρ) = 2.82 kg·m−3 for unloaded aqueous 3A1P solutions.

VmE·10−6 /m 3·mol−1 = x 2(1 − x 2) ∑ Ai (1 − 2x 2)i i=0

(3)

The excess molar volumes can be expressed as VmE·10−6 /m 3·mol−1 =

x1M1 + x 2M 2 xM xM − 1 o1 − 2 o 2 ρ ρ1 ρ2 (4)

where x, M, and ρ indicate mole fraction, molecular weight, and density of the composition, respectively. In this work, integers 1 and 2 refer to water and 3A1P while superscript o denotes the pure liquid. Values of excess molar volumes at different temperatures were calculated, and are tabulated in Table 3. It is already known that negative or positive VEm values are the results from physical, chemical, and structural properties of all components in the mixture. Over the entire range of mole 174

DOI: 10.1021/acs.jced.5b00412 J. Chem. Eng. Data 2016, 61, 173−181

Journal of Chemical & Engineering Data

Article

Table 3. Densities ρ and Excess Molar Volumes VEm of Aqueous 3A1P Solutions at Different Temperatures, Mass, and Mole Fractions. Experiments Were Performed at Atmospheric Pressure (P = 1013 mbar).a T K

VEm·10−6

ρ kg·m

−3

293.15 298.15 303.15 308.15 313.15 318.15 323.15

998.7 997.3 995.7 993.9 991.9 989.7 987.3

293.15 298.15 303.15 308.15 313.15 318.15 323.15

1002.2 1000.4 998.4 996.3 994.0 991.6 989.0

293.15 298.15 303.15 308.15 313.15 318.15 323.15

1005.9 1003.7 1001.3 998.8 996.2 993.3 990.6

293.15 298.15 303.15 308.15 313.15 318.15 323.15

1008.8 1006.0 1003.1 1000.1 997.1 993.9 990.6

293.15 298.15 303.15 308.15 313.15 318.15 323.15

1011.3 1008.2 1005.0 1001.8 998.5 995.0 991.5

−1

m ·mol 3

w2 = 0.10, −0.030 −0.032 −0.033 −0.033 −0.035 −0.035 −0.036 w2 = 0.20, −0.131 −0.131 −0.131 −0.132 −0.133 −0.133 −0.133 w2 = 0.30, −0.254 −0.251 −0.248 −0.246 −0.244 −0.241 −0.241 w2 = 0.41, −0.388 −0.379 −0.370 −0.362 −0.356 −0.350 −0.343 w2 = 0.51, −0.545 −0.533 −0.522 −0.515 −0.509 −0.500 −0.491

T K

VEm·10−6

ρ −3

kg·m

T

−1

m ·mol 3

K

VEm·10−6

ρ kg·m

−3

x2 = 0.027 328.15 333.15 338.15 343.15 348.15 353.15

984.8 983.0 980.3 977.5 974.5 971.2

−0.035 −0.053 −0.054 −0.057 −0.057 −0.058

293.15 298.15 303.15 308.15 313.15 318.15 323.15

1015.4 1011.8 1008.0 1003.9 1001.0 997.2 993.3

x2 = 0.059 328.15 333.15 338.15 343.15 348.15 353.15

986.3 983.5 980.5 977.5 974.3 971.0

−0.135 −0.133 −0.133 −0.135 −0.136 −0.136

293.15 298.15 303.15 308.15 313.15 318.15 323.15

1014.9 1011.2 1007.3 1003.4 999.2 995.6 991.7

x2 = 0.094 328.15 333.15 338.15 343.15 348.15 353.15

987.6 984.5 981.3 978.0 974.6 971.1

−0.241 −0.236 −0.235 −0.235 −0.234 −0.233

293.15 298.15 303.15 308.15 313.15 318.15 323.15

1009.8 1005.9 1002.0 998.0 994.0 990.0 986.0

x2 = 0.142 328.15 333.15 338.15 343.15 348.15 353.15

987.9 984.5 981.9 978.3 974.7 971.1

−0.355 −0.346 −0.365 −0.361 −0.359 −0.357

293.15 298.15 303.15 308.15 313.15 318.15 323.15

1001.4 997.5 993.5 989.5 985.5 981.5 977.5

x2 = 0.200 328.15 333.15 338.15 343.15 348.15 353.15

988.0 984.4 980.8 977.5 972.9 970.8

−0.488 −0.475 −0.472 −0.480 −0.453 −0.502

293.15 298.15 303.15 308.15 313.15 318.15 323.15

987.5 983.6 979.6 975.5 971.5 967.5 963.4

−1

m ·mol 3

w2 = 0.61, −0.797 −0.777 −0.756 −0.726 −0.741 −0.728 −0.715 w2 = 0.70, −0.906 −0.887 −0.868 −0.852 −0.826 −0.824 −0.815 w2 = 0.80, −0.945 −0.931 −0.918 −0.906 −0.895 −0.886 −0.876 w2 = 0.91, −0.795 −0.753 −0.747 −0.742 −0.738 −0.735 −0.731 w2 = 1.00, 0 0 0 0 0 0 0

VEm·10−6

ρ

T K

kg·m

−3

m3·mol−1

x2 = 0.275 328.15 333.15 338.15 343.15 348.15 353.15

989.5 985.6 981.6 977.6 973.6 969.5

−0.707 −0.685 −0.676 −0.667 −0.658 −0.650

x2 = 0.347 328.15 333.15 338.15 343.15 348.15 353.15

987.8 983.9 979.9 975.8 971.6 967.4

−0.808 −0.787 −0.778 −0.769 −0.758 −0.748

x2 = 0.502 328.15 333.15 338.15 343.15 348.15 353.15

981.9 977.7 973.2 969.1 965.1 961.2

−0.867 −0.830 −0.804 −0.797 −0.802 −0.812

x2 = 0.704 328.15 333.15 338.15 343.15 348.15 353.15

973.4 969.3 965.2 961.0 956.9 952.7

−0.728 −0.694 −0.690 −0.686 −0.681 −0.677

x2 = 1.000 328.15 333.15 338.15 343.15 348.15 353.15

959.3 955.8 951.7 947.6 943.5 939.3

0 0 0 0 0 0

Standard uncertainties u are u(T) = 0.03 K, u(w) = 0.01, u(P) = 20 mbar. Instrument standard uncertainty = 0.05 kg·m−3. The combined expanded uncertainty for density measurement Uc(ρ) is 2.82 kg·m−3 (95% level of confidence, k = 2).

a

correlated using a second order polynomial function. Moreover, recent publications have illustrated that the temperature-dependent coefficient can also be correlated using a linear function.28,33 By using a second order Redlich−Kister method with temperature linear parameters to analyze densities of unloaded 3A1P solutions, an average absolute deviation value of 0.5 kg·m−3 was determined. Densities of aqueous 3A1P solutions were also analyzed using the method of Jouyban−Acree.34 According to this method, densities of binary mixtures such as that of alkanolamines and water at various temperatures and concentrations can be calculated using the expression:

fractions and temperatures studied in this work, negative values of VEm were obtained suggesting contraction of volumes took place upon mixing 3A1P and water molecules. The reasons for volume contraction may be due to the formation of hydrogen bonds between the −OH group of 3A1P and water molecules,23 and could also be due to nonaqueous molecules filling the void spaces in water lattices.24 Similar behavior has also been reported for other alkanolamine−water systems.19,24−31 A second order polynomial version of eq 3 correlated the experimental data satisfactorily and was used to fit excess molar volumes of 3A1P solutions. Typical plots of VEm values against mole fractions of 3A1P are shown in Figure 4. The values of adjustable coefficients (Ai, with i = 0 to 2) together with the R2 values of the regression lines are presented in Table 4. Mandal et al.32 proposed that the adjustable coefficient Ai, is temperature dependent and can be

i=n ⎡ B (x − x 2)n ⎤ ln ρm , T = x1 ln ρ1, T + x 2 ln ρ2, T + x1x 2 ∑ ⎢ i 1 ⎥ ⎣ ⎦ T i=0

(5) 175

DOI: 10.1021/acs.jced.5b00412 J. Chem. Eng. Data 2016, 61, 173−181

Journal of Chemical & Engineering Data

Article

Table 4. Redlich−Kister Second Order Parameters at Different Temperatures

Figure 2. Densities of pure 3A1P as a function of temperatures at mass fraction equal to 1. Data from this work are labeled as △, while gray ◆, +, ▶, ○ and represent the work of Kermanpour and Niakan,12 Kermanpour et al.,15 Herba et al.,16 and Alvarez et al.,14 respectively. A linear correlation between densities and temperatures is shown as a dotted line.

T/K

A0

A1

A2

R2

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

−3.99 −3.92 −3.85 −3.78 −3.74 −3.71 −3.66 −3.62 −3.48 −3.39 −3.36 −3.34 −3.34

−0.32 −0.24 −0.17 −0.08 −0.06 −0.03 0.01 0.03 −0.05 −0.03 −0.01 0.04 −0.02

1.91 1.81 1.70 1.56 1.46 1.45 1.38 1.24 1.16 0.89 0.79 0.84 0.77

0.9928 0.9934 0.9942 0.9957 0.9943 0.9944 0.9946 0.9949 0.9951 0.9937 0.9948 0.9952 0.9982

and Bi is the model constant obtained upon regression of the experimental data. The number of constants can be varied between 0 to n. This method was employed by Stec et al.29 recently in their studies of densities of aminoethylethanolamine solutions (AEEA), and they found that this method worked well with their experimental data. In this work, a second order form of eq 5 was used to correlate the density data of 3A1P solutions. An average deviation of 2.0 kg·m−3 between our experimental data and predicted densities was calculated, and the regressed parameters are listed in Table 5. Table 5. Regressed Parameters of Jouyban−Acree Method for 3A1P Solutions

Figure 3. Densities of H2O (1) + 3A1P (2) solutions at different temperatures T (in Kelvin): 293.15 (■), 298.15 (○), 303.15 (▲), 308.15 (+), 313.15 (⧫), 318.15 (◊), 323.15 (▶), 328.15 (|), 333.15 (◀), 338.15 (◁), 343.15 (●), 348.15 (×) and 353.15 (⬟). Dotted lines are constructed based on calculated densities from Redlich−Kister method.

temp range (K)

B0

B1

B2

R2

293.15−353.15

17.58

12.79

−21.21

0.98

Third, a semiempirical model proposed by Gonzalez-Olmos and Iglesias30 was also used to represent our experimental data. In this case, densities of aqueous 3A1P solutions are determined using eq 6: i=N

ρ=

∑ Cix i

(6)

i=0

where x is the mole fraction of 3A1P, and Ci is a polynomial coefficient which is dependent on temperature T as shown by eq 7. The degree of x and T in both equations can be varied from 0 to N and Q, respectively. In eq 7, Cij refers to a parameter based on regression of Ci at different temperatures. j=Q

Ci =

∑ CijT j (7)

j=0 30

In the works of Gonzalez-Olmos and Iglesias and Dumitrescu et al.,35 they exploited a second-order version of eqs 6 and 7 to analyze their data, however in this work a thirdorder polynomial of eq 6 significantly improved the correlation between densities and mole fractions of 3A1P. A second-order polynomial of eq 7 was applied to correlate the change of parameters Ci against temperatures. The values of parameters Cij are listed in Table 6, and an average deviation of 0.7 kg·m−3 was determined. A semiempirical method reported by Emmerling et al.36 can also be used to represent densities of aqueous 3A1P solutions ρm.

Figure 4. Excess molar volumes VEm for H2O (1) and 3A1P (2) solutions at 313.15 (●), 338.15 K (⬟) and 353.15 K (■). Dotted lines are obtained with a second-order Redlich−Kister equation.

where ρm,T, ρ1,T, and ρ2,T are densities of the mixture, pure components 1 and 2 at temperature T, respectively. The mole fraction of components 1 and 2 are expressed as x1 and x2 in eq 5, 176

DOI: 10.1021/acs.jced.5b00412 J. Chem. Eng. Data 2016, 61, 173−181

Journal of Chemical & Engineering Data

Article

Table 6. Values of Parameters Based on Gonzalez-Olmos and Iglesias method T = (293.15−353.15) K C00 C02 C21 R2

C10 C12 C31

0.7814 −3.24 × 10−6 0.0211 0.9921

C01 C20 C22

2.3303 1.58 × 10−5 −0.0114

ρm = x1ρ1 + x 2ρ2 + x1x 2[D1 + D2T + D3T 2 + (D4 + D5T + D6T )(x1 − x 2) + (D7 + D8T + D9T 2)(x1 − x 2)2 ]

(14)

The a and b parameters are acquired from the intercept and slope of the regression, respectively. Values of fitted coefficients are tabulated in Table 8, and an average deviation of 1.3 kg·m−3

(8)

where integers 1 and 2 refer to water and 3A1P, respectively. An average deviation value of 0.6 kg·m−3 was calculated and fitted parameters Di, obtained by solving eq 8 simultaneously are shown in Table 7.

Table 8. Weiland’s Method Parameters

Table 7. Values of Parameters Based on Emmerling Method T = (293.15−353.15) K D6 D7 D8 D9 R2

−0.0121 2.1210 1.55 × 10−5

ρ /kg·m−3 = a + b·T /K

2

0.8004 −3.85 × 10−3 4.69 × 10−6 0.9463 −5.09 × 10−3

C11 C30 C32

showed that densities of pure amine can be modeled using a second order polynomial function.18,27 However, as illustrated in Figure 2, the change in densities of 3A1P against temperatures is linear and can be presented using eq 14.

This method takes into account contributions from temperatures T, mole fraction xi, and densities of pure components ρi, as shown in eq 8:

D1 D2 D3 D4 D5

1.68 × 10−3 −4.0163 −2.81 × 10−5

6.96 × 10−6 0.3766 2.74 × 10−3 4.64 × 10−6 0.9935

parameter

value

a b V* R2

1222.1 −0.8 −3.41 0.985

between our experimental data and predicted densities was determined. Figure 5 compares the ratios between experimental density data and calculated values from the Redlich−Kister, Jouyban-Acree,

Finally, we also explored the possibility of utilizing Weiland’s equation to represent densities of unloaded 3A1P solutions. The original method was introduced by Weiland et al.18 and has been used to predict the densities of CO2-loaded solutions.19,37,38 In this method densities ρ are calculated from contributions of the total molar volume V, mole fraction xi, and molecular weight of components i in the solution Mi, as illustrated in eq 9: ρ=

x1M1 + x 2M 2 + x3M3 V

(9)

where integers 1, 2, and 3 represent water, 3A1P, and CO2, respectively. Equation 9 can be rearranged into eqs 10 and 11 to take into consideration interactions between molecules.18 Here, VCO2, V*, c, and d represent interaction parameters derived from solving both equations. V = x1V1 + x 2V2 + x3VCO2 + x1x 2V * + x 2x3V **

(10)

V ** = c + dx 2

(11)

Figure 5. Ratio between calculated and experimental density data for 3A1P solutions. A ratio value of 1 indicates the calculated density perfectly fits the experimental density value. Methods used: Redlich− Kister (+), Emmerling (○), Weiland (◁), Jouyban-Acree (□), and Gonzalez-Olmos and Iglesias (×).

To apply the Weiland’s method for representing densities of unloaded solutions, the contributions from CO2 in the original method are set to zero (VCO2 and V**). Equations 9 and 10 can then be simplified into eqs 12 and 13. ρ=

x1M1 + x 2M 2 V

V = x1V1 + x 2V2 + x1x 2V *

Gonzalez-Olmos, and Iglesias, Emmerling, and Weiland’s methods. A ratio value of 1 indicates that the calculated density perfectly fits the experimental density value. Generally, the five methods discussed in this section are able to represent densities of unloaded 3A1P solutions satisfactorily. The AAD and AMD values calculated based on methods discussed in this section are also listed in Table 9. The Redlich−Kister method correlates densities of unloaded 3A1P solutions with the lowest AAD value; hence, it has been employed extensively in the field. However, in certain circumstances, the Redlich−Kister equation does not correlate unsymmetrical curves very well.31 The methods of

(12) (13)

The density−temperature coefficient values from Cheng et al.39 were used to calculate the molar volumes of pure water. Furthermore, molar volumes of pure amine were determined from measurements performed in this work. Our search in literature 177

DOI: 10.1021/acs.jced.5b00412 J. Chem. Eng. Data 2016, 61, 173−181

Journal of Chemical & Engineering Data

Article

Table 9. Comparison of Average and Maximum Deviations for Unloaded 3A1P Solutions between Models Studied in This Work method

average deviation (kg·m−3)

maximum deviation (kg·m−3)

Redlich−Kister Jouyban−Acree Iglesias Gonzalez−Olmos and Emmerling Weiland

0.5 2.0 0.7 0.6 1.3

1.9 6.1 2.2 0.7 3.5

Emmerling and Gonzalez-Olmos and Iglesias are also able to correlate densities of 3A1P solutions with minimal average deviations. In addition, the lowest AMD value is obtained from the Emmerling method. Although the average deviation values of Jouyban−Acree and Weiland methods are larger than that of other methods discussed in this work, upon considering our experimental uncertainty, we concluded that these deviations are still acceptable and within experimental error. However, it should also be noted that at certain concentrations, the maximum deviations between experimental and predicted density data are found to be larger than our calculated uncertainty, as demonstrated in Figure 5 and Table 9. 4.2. Densities of H2O (1), 3A1P (2), and CO2 (3) Solutions. In this work, densities of carbonated 3A1P solutions were measured at mass fractions of 0.1 and 0.5, and the results are summarized in Tables 10 and 11, respectively. Experiments were

Table 11. Densities of CO2-Loaded Aqueous 3A1P Solutions at Mass Fraction 0.5 of 3A1P at Different Temperatures, CO2Loading Values α, and CO2 Mole Fractions x3. Experiments Were Performed at Atmospheric Pressure (P = 1013 mbar)a

0.1

0.2

x3 =

0.003

0.005

0.1

x3 =

0.008

0.020

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

0.2

0.25

0.33

0.039

0.047

0.062

1071.3 1068.5 1065.7 1062.8 1059.8 1056.8 1053.8 1050.7 1047.5 1044.3 1041.0 1037.7 1034.3

1092.6 1090.0 1087.3 1084.5 1081.7 1078.9 1076.0 1073.0 1070.0 1066.9 1063.8 1060.6 1057.3

ρ/kg·m−3 1021.9 1018.9 1015.7 1012.5 1009.2 1005.8 1002.4 998.9 995.3 991.7 988.0 984.3 980.5

1035.5 1032.5 1029.4 1026.3 1023.1 1019.9 1016.6 1013.2 1009.8 1006.3 1002.7 991.0 995.4

1055.7 1052.8 1049.9 1047.0 1043.9 1040.8 1037.7 1034.5 1031.2 1027.9 1024.5 1021.0 1017.5

a

0.3

0.4

0.5

0.008

0.011

0.013

1019.5 1017.8 1015.8 1013.4 1010.9 1007.9 1006.0 1002.3 999.5 996.7 993.8 990.9 987.8

1022.8 1021.0 1019.0 1016.5 1013.8 1010.7 1008.0 1005.2 1002.6 998.5 996.4 992.9 990.8

Standard uncertainties u are u(x3) = 0.001, u(T) = 0.03 K, u(w) = 0.01, u(P) = 20 mbar. Instrument standard uncertainty = 0.05 kg·m−3. The combined expanded uncertainty for density measurement Uc(ρ) is 4.32 kg·m−3 (95% level of confidence, k = 2).

ρ/kg·m−3

T/K 293.15 298.15 303.15 308.15 313.15 318.15 323.15 328.15 333.15 338.15 343.15 348.15 353.15

0.04

T/K

Table 10. Densities of CO2-Loaded Aqueous 3A1P Solutions at Mass Fraction 0.1 of 3A1P at Different Temperatures, CO2Loading Values α, and CO2 Mole Fractions x3. Experiments Were Performed at Atmospheric Pressure (P = 1013 mbar)a α (mol CO2/mol 3A1P) =

α (mol CO2/mol 3A1P)

1004.7 1003.2 1001.5 999.7 997.5 995.2 992.6 990.2 987.4 984.5 981.6 978.6 975.5

1009.4 1007.9 1006.2 1004.2 1001.9 999.4 997.3 994.1 991.4 988.4 985.5 982.5 979.3

1014.8 1013.2 1011.4 1009.4 1007.0 1004.4 1001.5 998.5 995.6 992.8 989.9 986.9 983.7

molecules leading to more closely packed molecules in the solution. Similar observations have been reported earlier in other carbonated alkanolamine systems.19,37,38 Two methods were utilized to represent densities of CO2loaded 3A1P solutions; the first method was based on the work of Weiland et al.,18 while the second method originated from a recent publication by Pinto et al.33 In Weiland’s method, densities of carbonated 3A1P solutions are determined by considering interactions between water, 3A1P, and CO2 molecules, as discussed earlier. These interaction parameters are regressed using experimental data by solving eqs 10 and 11. Values of these parameters are shown in Table 12, and an AAD of 1.3 kg·m−3 was calculated. In addition, the values of the amine−water interaction parameter V*, calculated for CO2-loaded and unloaded 3A1P solutions are very similar suggesting that Weiland’s method discussed in this work is able to represent densities of unloaded 3A1P solutions. As discussed by Pinto et al.,33 the proportionality method estimates densities of CO2-loaded solutions ρloaded, based on the densities of unloaded solutions ρunloaded, and the corresponding relationship is shown as follow, ρloaded = c·wCO2 + ρunloaded (15)

a

Standard uncertainties u are u(x3) = 0.001, u(T) = 0.03 K, u(w) = 0.01, u(P) = 20 mbar. Instrument standard uncertainty = 0.05 kg·m−3. The combined expanded uncertainty for density measurement Uc(ρ) is 4.32 kg·m−3 (95% level of confidence, k = 2).

performed at atmospheric pressure at different temperatures and CO2-loadings α, ranging from (0.1 to 0.5) mol CO2/mol 3A1P. Graphical representations of the experimental data are shown in Figure 6. General observation of the data suggests that densities of CO2-loaded 3A1P solutions are higher than that of unloaded solutions and decreasing as temperatures increase. Lower densities at higher temperatures are expected in view of molecules becoming more excited leading to more space between them. The increased density as CO2-loading increases can be explained by the exothermic reaction between CO2 and the 3A1P

where the amount of CO2 added into the solutions wCO2, can be calculated using eq 16, wCO2 = α ·Namine·MCO2 ·ρunloaded 178

(16) DOI: 10.1021/acs.jced.5b00412 J. Chem. Eng. Data 2016, 61, 173−181

Journal of Chemical & Engineering Data

Article

Table 13. Regressed Parameters of Proportionality Method parameter

value

c1 c2 R2

1.244 −1.3 × 10−3 0.975

A parity plot comparing the measured and calculated densities from Weiland and proportionality methods is shown in Figure 7.

Figure 7. Comparison between calculated and measured density data for CO2-loaded 3A1P solutions. A ratio value of 1 indicates the calculated density perfectly fits the experimental density value. Two different methods were used: Weiland (□) and proportionality (△).

The values of AMD and AAD calculated between experimental and predicted density data for the models studied are also listed in Table 14. On the basis of the average deviation values, it can be suggested that any of these methods may be applied for predicting densities of carbonated 3A1P solutions. It should also be noted that at certain concentrations, large maximum deviations are calculated from the proportionality method. These deviations may be minimized by modifying eq 16.

Figure 6. Temperature dependency of experimental density data for carbonated 3A1P solutions. The CO2-loading values at 0.10 3A1P mass fraction in panel A are 0.1 (■), 0.2 (●), 0.3 (▲), 0.4 (▼), and 0.5 (⧫). The CO2-loading values at 0.50 3A1P mass fraction in panel B are 0.04 (■), 0.1 (●), 0.2 (▲), 0.25 (▼), and 0.33 (⧫). Dotted lines are constructed based on the calculated density values from the Weiland method.

Table 12. Parameters of the Density Correlation Based on Weiland’s Method for CO2-Loaded 3A1P Solutions parameter

value

a b c d VCO2

1222.1 −0.8 −702.2 3004.3 31.48

V* R2

−3.26 0.985

5. CONCLUSION New density data of unloaded and CO2-loaded aqueous 3A1P were measured experimentally at (293.15 to 353.15) K over a wide composition range. The data of pure 3A1P were compared with that in the literature and minimal deviations were observed. In both cases, densities are found to be dependent on compositions of 3A1P and temperatures. Densities of carbonated 3A1P solutions are found to be higher than the unloaded 3A1P densities. The values of excess molar volumes for aqueous 3A1P solutions are negative over the compositions studied. The negative values are likely due to the formation of hydrogen bonds between molecules or nonaqueous molecules occupying void spaces between water molecules. Furthermore, uncertainty analysis was performed and values of (2.82 and 4.32) kg·m−3 were determined for unloaded and CO2-loaded 3A1P solutions, respectively. The experimental data were subjected to several semiempirical correlations: five models were considered for unloaded 3A1P solutions, and two models were discussed for carbonated 3A1P solutions. In the first part, the lowest average deviation value of 0.5 kg·m−3 between experimental and predicted data was calculated from a second-order polynomial of the Redlich− Kister equation. The methods of Emmerling, Gonzalez-Olmos and Iglesias, Weiland and Jouyban−Acree produced average deviations of (0.6, 0.7, 1.3 and 2.0) kg·m−3, respectively. On the

by taking into consideration the CO2-loading α, the number of moles of amine per gram of unloaded solution Namine, the molecular weight of CO2 MCO2, and the density of the unloaded solution. A dimensionless proportionality constant c is introduced, and this parameter is linearly dependent on temperatures as illustrated below:

c = c1 + c 2·T

(17)

During data analysis, these parameters (c1 and c2) are regressed against temperatures of the measurements, and the values are shown in Table 13. In agreement with eq 15, we observed a linear relationship between ρloaded and wCO2 for our CO2-loaded density data. An average deviation value of 2.1 kg·m−3 was calculated by using this method. 179

DOI: 10.1021/acs.jced.5b00412 J. Chem. Eng. Data 2016, 61, 173−181

Journal of Chemical & Engineering Data

Article

Table 14. Comparison of Average and Maximum Deviations for CO2-Loaded 3A1P Solutions between Models Studied in This Work method

average deviation (kg·m−3)

maximum deviation (kg·m−3)

Weiland Proportionality

1.3 2.1

3.8 12.0

(6) da Silva, E. F.; Svendsen, H. F. Computational Chemistry Study of Reactions, Equilibrium and Kinetics of Chemical CO2 Absorption. Int. J. Greenhouse Gas Control 2007, 1, 151−157. (7) Henni, A.; Li, J.; Tontiwachwuthikul, P. Reaction Kinetics of CO2 in Aqueous 1-Amino-2-Propanol, 3-Amino-1-Propanol, and Dimethylmonoethanolamine Solutions in the Temperature Range of 298−313 K Using the Stopped-Flow Technique. Ind. Eng. Chem. Res. 2008, 47, 2213−2220. (8) Sada, E.; Kumazawa, H.; Osawa, Y.; Matsuura, M.; Han, Z. Q. Reaction Kinetics of Carbon Dioxide with Amines in Non-Aqueous Solvents. Chem. Eng. J. 1986, 33, 87−95. (9) Crooks, J. E.; Donnellan, J. P. Kinetics and Mechanism of the Reaction Between Carbon Dioxide and Amines in Aqueous Solution. J. Chem. Soc., Perkin Trans. 2 1989, 331−333. (10) Dong, L.; Chen, J.; Gao, G. Solubility of Carbon Dioxide in Aqueous Solutions of 3-Amino-1-propanol. J. Chem. Eng. Data 2010, 55, 1030−1034. (11) Idris, Z.; Peresunko, N.; Jens, K. J.; Eimer, D. A. Equilibrium Solubility of Carbon Dioxide in Aqueous Solutions of 3-amino-1propanol, 4-amino-1-butanol and 5-amino-1-pentanol at Low Partial Pressures. Fluid Phase Equilib. 2015, 387, 81−87. (12) Kermanpour, F.; Niakan, H. Z. Experimental Excess Molar Properties of Binary Mixtures of (3-amino-1-propanol + isobutanol, 2propanol) at T = (293.15 to 333.15) K and modelling the excess molar volume by Prigogine−Flory−Patterson theory. J. Chem. Thermodyn. 2012, 54, 10−19. (13) Omrani, A.; Rostami, A. A.; Mokhtary, M. Densities and Volumetric Properties of 1,4-dioxane with Ethanol, 3-methyl-1-butanol, 3-amino-1-propanol and 2-propanol Binary Mixtures at Various Temperatures. J. Mol. Liq. 2010, 157, 18−24. (14) Á lvarez, E.; Cerdeira, F.; Gómez-Diaz, D.; Navaza, J. M. Density, Speed of Sound, Isentropic Compressibility, and Excess Volume of Binary Mixtures of 1-Amino-2-propanol or 3-Amino-1-propanol with 2Amino-2-methyl-1-propanol, Diethanolamine, or Triethanolamine from (293.15 to 323.15) K. J. Chem. Eng. Data 2010, 55, 2567−2575. (15) Kermanpour, F.; Niakan, H. Z.; Sharifi, T. Density and Viscosity Measurements of Binary Alkanol Mixtures from (293.15 to 333.15) K at Atmospheric Pressure. J. Chem. Eng. Data 2013, 58, 1086−1091. (16) Herba, H.; Czechowski, G.; Zywucki, B.; Stockhausen, M.; Jadzyn, J. Excess Molar Volumes of Binary Mixtures of Amino Alcohols with 1,4Dioxane. J. Chem. Eng. Data 1995, 40, 214−215. (17) Redlich, O.; Kister, A. T. Algebraic Representation of Thermodynamic Properties and the Classification of Solutions. Ind. Eng. Chem. 1948, 40, 345−348. (18) Weiland, R. H.; Dingman, J. C.; Cronin, D. B.; Browning, G. J. Density and Viscosity of Some Partially Carbonated Aqueous Alkanolamine Solutions and Their Blends. J. Chem. Eng. Data 1998, 43, 378−382. (19) Idris, Z.; Ang, L.; Eimer, D. A.; Ying, J. Density Measurements of Unloaded and CO2-Loaded 1-Dimethylamino-2-propanol at Temperatures (298.15 to 353.15) K. J. Chem. Eng. Data 2015, 60, 1419−1425. (20) Amundsen, T. G.; Oi, L. E.; Eimer, D. A. Density and Viscosity of Monoethanolamine plus Water plus Carbon Dioxide from (25 to 80) degrees C. J. Chem. Eng. Data 2009, 54, 3096−3100. (21) Spieweck, F.; Bettin, H. Solid and Liquid Density Determination: Review. Tech. Mess. 1992, 59, 285−292. (22) Jayarathna, C. K.; Elverhøy, A. B.; Jiru, Y.; Eimer, D. Experimentally based evaluation of accuracy of absorption equilibrium measurements. Energy Procedia 2013, 37, 834−843. (23) Pal, A.; Singh, W. Excess Molar Volumes of Linear and Cyclic Ethers + Chloroethenes at 298.15 K. J. Chem. Eng. Data 1996, 41, 428− 430.

basis of this work, it is apparent that the Redlich−Kister method is the best technique for correlating densities of 3A1P solutions. However, on the basis of our experimental uncertainties we concluded that for engineering purposes, any of these five methods may be employed. In this paper, densities of CO2-loaded solutions were fitted using Weiland and proportionality methods. The Weiland method represents densities of CO2-loaded solutions based on contributions of molecules while the proportionality method uses densities of unloaded solutions. Average deviation values of (1.3 and 2.1) kg·m−3 were calculated for Weiland and proportionality methods, respectively. Minimal deviation values suggest that both of these methods are suitable for correlating densities of carbonated 3A1P solutions. The experimental data reported in this work add to the existing thermodynamic database of possible amine-based solvents for CO2 capture, and can be utilized for engineering purposes. Furthermore, different methods discussed in this work would aid researchers in the field of available techniques to analyze experimental density data.

■

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.jced.5b00412. Densities of water at different temperatures (PDF)

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Tel.: +47 3557 4000. Funding

The authors are grateful to The Research Council of Norway through CLIMIT Program (Grant Number 199890) for financial support. Notes

The authors declare no competing financial interest.

■

REFERENCES

(1) Rochelle, G. T. Amine Scrubbing for CO2 Capture. Science 2009, 325, 1652−1654. (2) Arshad, M. W.; Svendsen, H. F.; Fosbøl, P. L.; von Solms, N.; Thomsen, K. Equilibrium Total Pressure and CO2 Solubility in Binary and Ternary Aqueous Solutions of 2-(Diethylamino)ethanol (DEEA) and 3-(Methylamino)propylamine (MAPA). J. Chem. Eng. Data 2014, 59, 764−774. (3) Puxty, G.; Rowland, R.; Allport, A.; Yang, Q.; Bown, M.; Burns, R.; Maeder, M.; Attalla, M. Carbon Dioxide Postcombustion Capture: A Novel Screening Study of the Carbon Dioxide Absorption Performance of 76 Amines. Environ. Sci. Technol. 2009, 43, 6427−6433. (4) Chowdhury, F. A.; Yamada, H.; Higashii, T.; Goto, K.; Onoda, M. CO2 Capture by Tertiary Amine Absorbents: A Performance Comparison Study. Ind. Eng. Chem. Res. 2013, 52, 8323−8331. (5) Mokraoui, S.; Valtz, A.; Coquelet, C.; Richon, D. Volumetric Properties of the Isopropanolamine−water Mixture at Atmospheric Pressure from 283.15 to 353.15 K. Thermochim. Acta 2006, 440, 122− 128. 180

DOI: 10.1021/acs.jced.5b00412 J. Chem. Eng. Data 2016, 61, 173−181

Journal of Chemical & Engineering Data

Article

(24) Mundhwa, M.; Alam, R.; Henni, A. Volumetric Properties, Viscosities, and Refractive Indices for Aqueous 2-((2-Aminoethyl)amino)ethanol Solutions from (298.15 to 343.15) K. J. Chem. Eng. Data 2006, 51, 1268−1273. (25) Narayanaswamy, K.; Rayer, A. V.; Kadiwala, S.; Henni, A. Volumetric Properties, Viscosities, Refractive Indices and Surface Tensions for (Dimethylpropanolamine (DMPA) + Water) Mixtures from 298.15 to 343.15 K. Thermochim. Acta 2012, 543, 218−225. (26) Rayer, A. V.; Kadiwala, S.; Narayanaswamy, K.; Henni, A. Volumetric Properties, Viscosities, and Refractive Indices for Aqueous 1-Amino-2-Propanol (Monoisopropanolamine (MIPA)) Solutions from (298.15 to 343.15) K. J. Chem. Eng. Data 2010, 55, 5562−5568. (27) Yang, F.; Wang, X.; Wang, W.; Liu, Z. Densities and Excess Properties of Primary Amines in Alcoholic Solutions. J. Chem. Eng. Data 2013, 58, 785−791. (28) Han, J. Y.; Jin, J.; Eimer, D. A.; Melaaen, M. C. Density of Water (1) + Monoethanolamine (2) + CO2 (3) from (298.15 to 413.15) K and Surface Tension of Water (1) + Monoethanolamine (2) from (303.15 to 333.15) K. J. Chem. Eng. Data 2012, 57, 1095−1103. ́ (29) Stec, M.; Tatarczuk, A.; Spiewak, D.; Wilk, A. Densities, Excess Molar Volumes, and Thermal Expansion Coefficients of Aqueous Aminoethylethanolamine Solutions at Temperatures from 283.15 to 343.15 K. J. Solution Chem. 2014, 43, 959−971. (30) Gonzalez-Olmos, R.; Iglesias, M. Influence of Temperature on Thermodynamics of Ethers + Xylenes. Fluid Phase Equilib. 2008, 267, 133−139. (31) Li, J.; Mundhwa, M.; Tontiwachwuthikul, P.; Henni, A. Volumetric Properties, Viscosities, and Refractive Indices for Aqueous 2-(Methylamino)ethanol Solutions from (298.15 to 343.15) K. J. Chem. Eng. Data 2007, 52, 560−565. (32) Mandal, B. P.; Kundu, M.; Bandyopadhyay, S. S. Density and Viscosity of Aqueous Solutions of (N-Methyldiethanolamine plus Monoethanolamine), (N-Methyldiethanolamine plus Diethanolamine), (2-Amino-2-methyl-1-propanol plus Monoethanolamine), and (2Amino-2-methyl-1-propanol plus Diethanolamine). J. Chem. Eng. Data 2003, 48, 703−707. (33) Pinto, D. D. D.; Monteiro, J.; Johnsen, B.; Svendsen, H. F.; Knuutila, H. Density Measurements and Modelling of Loaded and Unloaded Aqueous Solutions of MDEA (N-methyldiethanolamine), DMEA (N,N-dimethylethanolamine), DEEA (diethylethanolamine) and MAPA (N-methyl-1,3-diaminopropane). Int. J. Greenhouse Gas Control 2014, 25, 173−185. (34) Jouyban, A.; Fathi-Azarbayjani, A.; Khoubnasabjafari, M.; Acree, W. E. Mathematical Representation of the Density of Liquid Mixtures at Various Temperatures Using Jouyban-Acree Model. Indian J. Chem. Sect A-Inorg. Bio-Inorg. Phys. Theor. Anal. Chem. 2005, 44, 1553−1560. (35) Dumitrescu, V.; Budeanu, M. M.; Radu, S.; Cameniţa,̆ A. D. Densities and Viscosities of Binary Mixtures of 2-Methoxy-2methylpropane with n-Octane. Phys. Chem. Liq. 2015, 53, 242−251. (36) Emmerling, U.; Figurski, G.; Rasmussen, P. Densities and Kinematic Viscosities for the Systems Benzene + Methyl Formate, Benzene + Ethyl Formate, Benzene + Propyl Formate, and Benzene + Butyl Formate. J. Chem. Eng. Data 1998, 43, 289−292. (37) Jayarathna, S. A.; Kottage, D. A.; Eimer, D. A.; Melaaen, M. C. Densities of Partially Carbonated Aqueous Diethanolamine and Methyldiethanolamine Solutions. J. Chem. Eng. Data 2012, 57, 2975− 2984. (38) Han, J. Y.; Jin, J.; Eimer, D. A.; Melaaen, M. C. Density of Water (1) + Diethanolamine (2) + CO2 (3) and Water (1) + NMethyldiethanolamine (2) + CO2 (3) from (298.15 to 423.15) K. J. Chem. Eng. Data 2012, 57, 1843−1850. (39) Cheng, S.; Meisen, A.; Chakma, A. Predict Amine Solution Properties Accurately. Hydrocarb. Process. 1996, 75, 81−84.

181

DOI: 10.1021/acs.jced.5b00412 J. Chem. Eng. Data 2016, 61, 173−181