Density Measurements of Unloaded and CO2-Loaded 1

Mar 17, 2015 - In the first part of this work, densities of aqueous 1-dimethylamino-2-propanol (1DMA2P) at different mass fractions and temperatures a...
0 downloads 0 Views 1MB Size
Download PDF
Article pubs.acs.org/jced

Density Measurements of Unloaded and CO2‑Loaded 1‑Dimethylamino-2-propanol at Temperatures (298.15 to 353.15) K Zulkifli Idris,† Lucille Ang,† Dag A. Eimer,*,†,‡ and Jiru Ying‡ †

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

‡

ABSTRACT: In the first part of this work, densities of aqueous 1-dimethylamino2-propanol (1DMA2P) at different mass fractions and temperatures are presented. A linear relation between densities and temperatures was found, and the thermal expansion coefficient values were established. Subsequently a second order Redlich−Kister polynomial equation was employed to correlate excess molar volumes of the mixtures. In the second part of this work, densities of CO2-loaded 1DMA2P solutions at 0.30 and 0.55 mass fractions were measured at increasing temperatures and CO2 loadings. The data were then modeled, and evaluation with the estimated density values is discussed.

1. INTRODUCTION Utilization of aqueous alkanolamine solutions to chemically absorb carbon dioxide (CO2) releases from industrial processes can be acknowledged as a matured technology.1 A number of amines such as ethanolamine (MEA), diethanolamine (DEA), and methyl diethanolamine (MDEA) have been employed, and new candidates are being proposed and studied.2−5 Among them, tertiary amines are also a viable option due to the fact that they have lower regeneration energy requirement compared to conventional amines. Chowdhury et al. screened 24 tertiary amines and nominated seven amines as potential absorbents due to their high absorption rates and cyclic capacity performances.6 One of the amines is 1-dimethylamino2-propanol (1DMA2P), and is the subject of this study. Figure 1 depicts the chemical structure of 1DMA2P.

Furthermore, densities of aqueous CO2-loaded solutions at different temperatures and concentrations are reported. Previously, the Redlich−Kister equation8 has been used by researchers such as Pinto et al.,9 Hartono and Svendsen,10 Zhang et al.,11 Mather and co-workers,12,13 and Han et al.14,15 to accurately correlate experimental density data of aqueous amine solutions. Densities of CO2-loaded amine solutions were modeled using techniques published in the literature.16,17 In the present work, we applied Redlich−Kister8 and Weiland17 methods to analyze our experimental data of unloaded and CO2-loaded aqueous 1DMA2P solutions, respectively.

2. EXPERIMENTAL SECTION Chemicals used for this work are listed in Table 1. All the chemicals were used as received, without any purification. A Table 1. Details of the Chemicals Used in This Work chemical name 1-dimethylamino-2-propanol (1DMA2P) carbon dioxide (CO2)

Figure 1. A schematic representation of 1DMA2P.

purification method

Alfa Aesar

0.99

none

AGA Norge AS

0.9999

none

precision balance (Mettler Toledo XS-403S) with an accuracy of 1·10−6 kg was used to weigh all required chemicals. Aqueous solutions of 1DMA2P were prepared by mixing the required amount with degassed Milli-Q water (conductivity 18.2 MΩ· cm). As a quality control step, acid−base titration was also

Comprehensive studies on the physical and chemical properties of amines are required before they can be exploited in the CO2 absorption process. Physical property data such as densities of several amines have been reported and can be found in the literature. Chowdhury et al.7 presented densities of 1DMA2P at different mole fractions and temperatures of up to 323.15 K, and in this work we present new densities data of aqueous 1DMA2P solutions at varying mass fractions ranging from 0.1 to 1 and temperatures of (298.15 to 353.15) K. © XXXX American Chemical Society

mole fraction purity

source

Received: December 12, 2014 Accepted: March 9, 2015

A

DOI: 10.1021/je501126j J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 2. Densities ρ, Thermal Expansion Coefficients αp, and Excess Molar Volumes VmE of Aqueous 1DMA2P Solutions at Different Temperatures, Mass, and Mole Fractionsa T K

αp·10−4

ρ kg·m

−3

K

−1

298.15 303.15 308.15 313.15 318.15 323.15

992.5 990.8 988.9 986.7 984.2 982.1

5.36 5.37 5.39 5.40 5.42 5.43

298.15 303.15 308.15 313.15 318.15 323.15

989.5 987.2 984.6 981.9 979.0 976.0

6.30 6.32 6.34 6.36 6.38 6.40

298.15 303.15 308.15 313.15 318.15 323.15

984.6 981.4 978.0 974.5 970.9 967.2

7.95 7.98 8.02 8.05 8.08 8.11

298.15 303.15 308.15 313.15 318.15 323.15

976.7 972.8 968.7 964.6 960.5 956.3

8.80 8.84 8.88 8.92 8.96 9.00

298.15 303.15 308.15 313.15 318.15 323.15

967.2 962.9 958.5 954.1 949.4 944.8

9.63 9.68 9.73 9.77 9.82 9.87

298.15 303.15 308.15 313.15 318.15 323.15

958.7 954.2 949.7 945.0 940.4 935.6

9.99 10.04 10.09 10.14 10.20 10.25

298.15 303.15 308.15 313.15 318.15 323.15

948.9 944.2 939.6 934.8 930.0 925.2

10.34 10.39 10.44 10.50 10.55 10.61

298.15 303.15 308.15 313.15 318.15 323.15

929.1 924.3 919.5 914.7 909.8 904.9

10.77 10.82 10.88 10.94 11.00 11.06

VmE·10−6

T

−1

m ·mol 3

K

w2 = 0.10, −0.264 −0.268 −0.271 −0.274 −0.273 −0.283 w2 = 0.20, −0.613 −0.614 −0.615 −0.617 −0.618 −0.620 w2 = 0.30, −0.991 −0−983 −0.975 −0.969 −0.962 −0.958 w2 = 0.40, −1.376 −1.361 −1.344 −1.332 −1.321 −1.313 w2 = 0.50, −1.816 −1.798 −1.782 −1.769 −1.749 −1.740 w2 = 0.55, −1.946 −1.927 −1.912 −1.894 −1.881 −1.868 w2 = 0.60, −2.042 −2.020 −2.005 −1.987 −1.969 −1.959 w2 = 0.71, −2.376 −2.359 −2.345 −2.338 −2.323 −2.320

x2 = 0.019 328.15 333.15 338.15 343.15 348.15 353.15 x2 = 0.042 328.15 333.15 338.15 343.15 348.15 353.15 x2 = 0.070 328.15 333.15 338.15 343.15 348.15 353.15 x2 = 0.104 328.15 333.15 338.15 343.15 348.15 353.15 x2 = 0.149 328.15 333.15 338.15 343.15 348.15 353.15 x2 = 0.176 328.15 333.15 338.15 343.15 348.15 353.15 x2 = 0.208 328.15 333.15 338.15 343.15 348.15 353.15 x2 = 0.300 328.15 333.15 338.15 343.15 348.15 353.15

B

αp·10−4

ρ

VmE·10−6

−1

m3·mol−1

979.1 975.3 972.5 970.6 967.4 963.2

5.45 5.46 5.48 5.49 5.51 5.52

−0.279 −0.261 −0.267 −0.294 −0.318 −0.345

972.9 969.6 966.2 962.7 959.1 955.3

6.42 6.44 6.46 6.48 6.51 6.53

−0.621 −0.623 −0.624 −0.626 −0.649 −0.694

963.3 959.4 955.2 951.2 946.8 940.3

8.15 8.18 8.21 8.25 8.28 8.32

−0.950 −0.946 −0.936 −0.935 −0.946 −0.923

952.0 947.7 943.2 938.6 934.0 929.4

9.04 9.08 9.12 9.16 9.21 9.25

−1.304 −1.297 −1.286 −1.276 −1.289 −1.323

940.2 935.5 930.7 925.9 920.9 916.0

9.92 9.97 10.02 10.07 10.12 10.17

−1.728 −1.717 −1.706 −1.698 −1.707 −1.736

930.6 926.0 921.1 916.1 911.1 906.0

10.30 10.35 10.41 10.46 10.52 10.57

−1.847 −1.843 −1.830 −1.818 −1.826 −1.851

920.3 915.3 910.3 905.2 900.1 894.9

10.67 10.72 10.78 10.84 10.90 10.96

−1.945 −1.928 −1.914 −1.900 −1.906 −1.926

899.8 894.8 889.7 884.5 879.3 874.0

11.13 11.19 11.25 11.31 11.38 11.44

−2.304 −2.295 −2.282 −2.271 −2.276 −2.293

kg·m

−3

K

DOI: 10.1021/je501126j J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 2. continued T

ρ

αp·10−4

VmE·10−6

T

ρ

αp·10−4

VmE·10−6

K

kg·m−3

K−1

m3·mol−1

K

kg·m−3

K−1

m3·mol−1

298.15 303.15 308.15 313.15 318.15 323.15

905.6 900.9 896.0 891.1 886.2 881.2

11.12 11.19 11.25 11.31 11.38 11.44

876.2 871.1 865.9 860.7 855.5 850.2

11.51 11.58 11.64 11.71 11.78 11.85

−2.398 −2.387 −2.370 −2.362 −2.367 −2.379

298.15 303.15 308.15 313.15 318.15 323.15

876.5 871.1 866.9 862.0 857.1 852.1

11.41 11.48 11.54 11.61 11.68 11.75

847.1 842.0 836.9 831.7 826.5 821.3

11.82 11.89 11.96 12.03 12.10 12.18

−1.882 −1.869 −1.856 −1.844 −1.841 −1.846

298.15 303.15 308.15 313.15 318.15 323.15

860.5 855.7 850.8 846.0 841.0 836.1

11.57 11.63 11.70 11.77 11.84 11.91

831.1 826.1 821.1 816.0 810.9 805.7

11.98 12.06 12.13 12.20 12.28 12.35

−1.200 −1.193 −1.187 −1.182 −1.181 −1.171

298.15 303.15 308.15 313.15 318.15 323.15

845.2 840.4 835.6 830.7 825.9 820.9

11.62 11.68 11.75 11.82 11.89 11.96

816.0 811.1 806.2 801.2 796.2 791.2

12.04 12.11 12.18 12.26 12.33 12.41

w2 = 0.81, −2.428 −2.427 −2.415 −2.411 −2.403 −2.403 w2 = 0.91, −1.884 −1.827 −1.885 −1.887 −1.881 −1.886 w2 = 0.96, −1.200 −1.202 −1.193 −1.209 −1.189 −1.206 w2 = 1.00, 0 0 0 0 0 0

x2 = 0.427 328.15 333.15 338.15 343.15 348.15 353.15 x2 = 0.638 328.15 333.15 338.15 343.15 348.15 353.15 x2 = 0.807 328.15 333.15 338.15 343.15 348.15 353.15 x2 = 1.000 328.15 333.15 338.15 343.15 348.15 353.15

0 0 0 0 0 0

Standard uncertainties u are u(T) = ± 0.03 K, u(w) = ± 0.01. Instrument accuracy = ± 0.05 kg·m−3. The combined expanded uncertainty for density measurement Uc(ρ) is ± 5.96 kg·m−3 (95% level of confidence, k = 2). Standard deviation implies k = 1.

a

case of unloaded aqueous 1DMA2P solutions, we calculated a value of 1.3 kg·m−3·K−1 for the change of densities against temperatures, giving an uncertainty of ± 0.039 kg·m−3. The uncertainty of the mass fraction is estimated from the purity of 1DMA2P, and the value is ± 0.01. Thus, the uncertainty caused by mass fraction is ± 2.98 kg·m−3. The combined standard uncertainty can be calculated using a root-sum of squares formula of the terms involved, and the value obtained is ± 2.98 kg·m−3. Therefore, for unloaded aqueous 1DMA2P solutions the combined expanded uncertainty is Uc(ρ) = ± 5.96 kg·m−3 (at 95% confidence level, k = 2). The combined standard uncertainty for CO2-loaded aqueous 1DMA2P solutions is ± 4.08 kg·m−3, taking into consideration similar factors as discussed earlier and contribution from the error in CO2-loading values. At 95% confidence level, a value of Uc(ρ) = ± 8.16 kg·m−3 is quoted as the combined expanded uncertainty.

employed to determine the actual concentration and mass fraction of 1DMA2P solutions. In this case, approximately 1−2 g of aqueous 1DMA2P was titrated using 1 mol·L−1 HCl to an equivalence point to determine the actual concentration of 1DMA2P. On the basis of our experiments, we found that the difference between the mass fractions calculated from titration and routine sample preparation was negligible. The CO2, normally administered at a rate of 0.15 dm3·min−1, was bubbled into aqueous 1DMA2P solutions to prepare CO2loaded solutions. The required time needed in order to achieve the desired CO2 loadings was calculated using the ideal gas law expression. The resulting aqueous CO2-loaded amine solutions were analyzed further to determine the accurate CO2 loadings according to previously published methods.18,19 A digital density meter from Anton Paar (DMA 4500) was utilized for measuring densities of Milli-Q water, unloaded and CO2-loaded aqueous 1DMA2P solutions. Before density measurements were executed, the density meter was calibrated according to the instrument specification. It should also be noted that all experiments in this work were performed at atmospheric pressure.

4. RESULTS AND DISCUSSION 4.1. Densities of H2O (1) and 1DMA2P (2) Solutions. The densities of aqueous 1DMA2P solutions at increasing mass fractions are tabulated in Table 2. Measurements were performed at temperatures ranging from (298.15 to 353.15) K. The densities of pure component of 1DMA2P (mass fraction equals 1.0) are compared to the literature values from Chowdhury et al.,7 and a graphical representation is shown in Figure 2. Although a small systematic deviation can be seen, upon consideration of the uncertainties in our measurements

3. ASSESSMENT OF EXPERIMENTAL UNCERTAINTIES The reported experimental density data can be influenced by several factors and these are summarized in this section. The density meter has two sources of uncertainties as reported by the manufacturer: the given accuracy for temperature is ± 0.03 K, and instrument density accuracy is ± 0.05 kg·m−3. In the C

DOI: 10.1021/je501126j J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 3. Parameters A0 and Bi of Linear Relationship (eq 1) between Densities of Aqueous 1DMA2P Solutions and Temperatures at Different Mass w2 and Mole x2 Fractions. The Levels of Confidence R2 of the Lines Are Also Given

Figure 2. Comparison of densities for 1DMA2P between this work (●) and Chowdhury et al.7 (■). Correlation between densities and temperatures is shown as a dotted line, and error bars for our measurements are also illustrated.

w2

x2

A0

Bi

R2

0.10 0.20 0.30 0.40 0.50 0.55 0.60 0.71 0.81 0.91 0.96 1.00

0.019 0.042 0.070 0.104 0.149 0.176 0.201 0.300 0.427 0.638 0.807 1.000

1152.90 1176.95 1219.73 1233.79 1245.77 1244.98 1241.95 1227.96 1206.63 1175.10 1157.65 1138.20

−0.533 −0.624 −0.784 −0.860 −0.932 −0.958 −0.981 −1.001 −1.008 −1.001 −0.996 −0.982

0.9901 0.9953 0.9940 0.9992 0.9996 0.9997 0.9997 0.9997 0.9997 0.9996 0.9999 0.9999

change of the thermal expansion coefficients is less than that of densities. −Bi αp/K−1 = A 0 + Bi ·T /K (2)

(shown as error bars), we concluded that both data agree well with each other. However, there are no details of uncertainty of measurements in the work of Chowdhury et al.7 for a direct comparison with our work. Figure 3 displays plots of densities

The density data of aqueous 1DMA2P (plus the pure component values) were utilized to determine excess molar volumes of solutions. The excess molar volume VmE, as defined in eq 3 is the difference between the molar volume of a solution Vm, and the total molar volume of pure component i Vio, at an equivalent temperature and pressure. VmE = Vm −

∑ xiVio

(3)

Excess molar volumes of 1DMA2P solutions were calculated from densities by rearranging eq 3 into eq 4 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 represent mole fraction, molecular weight, and density, respectively. Integers 1 and 2 refer to water and 1DMA2P, while superscript o denotes the pure component. The values of excess molar volume for 1DMA2P solutions are displayed in Table 2. As can be seen, the excess molar volumes are negative over the entire range of 1DMA2P solutions. The negative VmE values suggest that a contraction in volume occurred from interactions of molecules of 1DMA2P and water upon mixing. Previously, similar observations were also reported in other alkanolamines−water systems.11,15,20 A polynomial Redlich−Kister equation8 as shown in eq 5 was used to correlate excess molar volumes of 1DMA2P solutions at different temperatures. Ai indicates empirical parameter and the number of parameters n, is kept as low as possible while ensuring good data representation.

Figure 3. Experimental density data of unloaded 1DMA2P solutions at different mass fractions w2: 0.10 (■), 0.20 (●), 0.30 (▲), 0.40 (▼), 0.50 (◆), 0.55 (◀), 0.60 (▶), 0.71 (□), 0.81 (○), 0.91 (|), 0.96 (◇), 1.00 (+). The correlation between densities and temperatures are shown as dotted lines.

against temperatures at different 1DMA2P mass fractions. It is apparent that densities decrease as temperature increases, as expected. The relationship between densities of 1DMA2P solutions and temperatures can be correlated with a linear expression as shown in eq 1, ρ /kg·m−3 = A 0 + Bi ·T /K

(1)

where A0 and Bi parameters refer to intercept on the y-axis and gradient of the straight line, respectively, and values of these parameters at different mass fractions are listed in Table 3. The parameters can also be used to calculate the thermal expansion coefficients αp, for 1DMA2P solutions by incorporating the values obtained from eq 1 into eq 2, and the resulting coefficients are included in Table 2. As can be seen from the table, the thermal expansion coefficients increase as the mass fractions of 1DMA2P in the solutions increase. At constant mass fraction, it can also be noted that as temperature increases, the change in the thermal coefficients is minimal: the relative

i=n

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

(5)

In this work, a second-order form of eq 5 corroborated the experimental data satisfactorily and was therefore used to fit excess molar volumes of 1DMA2P solutions. As a comparison, in the work reported by Chowdhury et al.,7 they have utilized a fifth-order polynomial to correlate their excess molar volumes of 1DMA2P. Typical examples of the fitting plots are shown in D

DOI: 10.1021/je501126j J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Figure 4, and it can be seen that there is a good agreement between the experimental data and the fitted Redlich−Kister

Table 5. Redlich−Kister Temperature Dependent Coefficients (eq 6) Redlich−Kister parameter

Redlich−Kister temperature coefficient

regressed value

A0

A00 A01 A02 A10 A11 A12 A20 A21 A22

−3.794 −0.0369 0.0000639 −45.383 0.246 −0.000366 −50.362 0.286 −0.000431

A1

A2

Table 6. Densities of CO2-Loaded Aqueous 1DMA2P Solutions at Different Temperatures, CO2-Loading Values α, and CO2 Mole Fractions x3, at Mass Fraction of 0.3a Figure 4. Excess molar volumes of 1DMA2P solutions at selected temperatures of 298.15 K (□), 308.15 K (○), and 343.15 K (+). The dotted lines are correlated using the second order form of the Redlich−Kister equation.

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

Table 4. Regressed Second Order Redlich−Kister Parameters (A0, A1, and A2) at Different Temperatures (eq 5) A0

A1

A2

R2

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

−9.1324 −9.0298 −9.0917 −9.0846 −9.0533 −9.0574 −9.0312 −8.8967 −8.9269 −8.8751 −8.8608 −8.8826

−4.3348 −4.3457 −4.1783 −4.0408 −4.0458 −3.9260 −3.8780 −3.8679 −3.8339 −3.8142 −3.8708 −4.0234

−3.3008 −3.2832 −3.1026 −3.1155 −2.9356 −2.9787 −2.8808 −2.8427 −2.8359 −2.8497 −3.0039 −3.1321

0.9984 0.9980 0.9985 0.9985 0.9985 0.9985 0.9984 0.9982 0.9981 0.9979 0.9974 0.9961

αb = 0.3

αb = 0.4

αb = 0.5

x3 = 0.007

x3 = 0.014

x3 = 0.020

x3 = 0.027

x3 = 0.034

1030.2 1026.8 1023.3 1019.7 1016.0 1012.2 1008.1 1004.3

1039.8 1036.5 1032.7 1029.5 1025.8 1021.9 1017.8 1011.0

ρ/kg·m−3 1004.9 1001.6 998.2 994.6 990.9 987.1 983.2 979.1 975.0 970.8 966.4 960.9

1013.4 1010.1 1006.7 1002.8 998.7 994.6 990.2 985.7 980.6 975.8

1026.0 1022.6 1019.1 1015.5 1011.9 1008.1 1004.3 1000.3 996.4

a Standard uncertainties u are u(x3) = ± 0.002, u(T) = ± 0.03 K, u(w) = ± 0.01. Instrument accuracy = ± 0.05 kg·m−3. The combined expanded uncertainty for density measurement Uc(ρ) is ± 8.16 kg·m−3 (95 % level of confidence, k = 2). Standard deviation implies k = 1. bα = mol CO2/mol 1DMA2P.

limitation imposed by using an atmospheric density cell giving rise to gas bubbles at high temperatures and CO2 loadings. This difficulty can be avoided by subjecting the measurements to a higher pressure, as reported in our previous publications.14,22 Figure 5 portrays plots of densities against temperatures for aqueous 1DMA2P solutions at different CO2-loading values. It can be observed from both panels that densities decrease with temperatures, but increase as the CO2 content increases. Recently, a new empirical approach utilizing densities of unloaded solutions for predicting densities of CO2-loaded solutions has been proposed by Pinto et al.9 In this work, the correlation described by Weiland et al.17 was used as a framework to further analyze the density data of CO2-loaded 1DMA2P solutions. The relationship between density of the solution ρ, the total molar volume V, and molecular weight of components in the solution Mi, is given in eq 7,

our previous publication,14 the Redlich−Kister parameters were then regressed as a function of temperature using a secondorder polynomial as shown in eq 6. The values of Ai0, Ai1, and Ai2 parameters are tabulated in Table 5. Ai = Ai0 + Ai1·(T /K) + Ai2 ·(T /K)2

αb = 0.2

T/K

correlation. The coefficients of Ai, with i ranging from 0 to 2 are compiled in Table 4. As demonstrated by Mandal et al.21 and

T/K

αb = 0.1

(6) −3

An average absolute deviation value of 0.31 kg·m was calculated by comparing our experimental and correlated data, while a maximum deviation of 1.65 kg·m−3 was determined. These deviations are smaller than the experimental uncertainty, thus negligible for engineering calculations. 4.2. Densities of H2O (1), 1DMA2P (2), and CO2 (3) Solutions. In this work, densities of aqueous CO2-loaded 1DMA2P solutions were also examined at two mass fractions of 0.30 and 0.55, and the results are listed in Tables 6 and 7, respectively. Experiments were conducted at different CO2loading values, α, starting from (0.1 to 0.5) mol CO2/mol 1DMA2P. The blank spaces in Tables 6 and 7 are due to the

ρ=

x1M1 + x 2M 2 + x3M3 V

(7)

where xi is the mole fraction of component i, and integers 1, 2, and 3 designate water, 1DMA2P, and CO2, respectively. To take into consideration interactions between CO2, water, and amine molecules, eq 7 can be rearranged into eqs 8 and 9.17 E

DOI: 10.1021/je501126j J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 7. Densities of CO2-Loaded Aqueous 1DMA2P Solutions at Different Temperatures, CO2-Loading Values α, and CO2 Mole Fractions x3, at Mass Fraction of 0.55a α = 0.1

α = 0.2

α = 0.3

α = 0.4

α = 0.5

x3 = 0.017

x3 = 0.034

x3 = 0.050

x3 = 0.065

x3 = 0.080

1031.4 1027.1 1022.7 1018.3 1013.8 1009.3 1004.8 1000.1 995.4

1060.1 1055.9 1051.8 1047.6 1043.4 1039.0

b

b

b

980.0 975.7 971.3 966.9 962.4 957.8 953.1 948.2 943.3 936.7 931.3

1004.6 1000.2 995.7 991.1 986.5 981.9 977.3 972.5 967.7 962.8 957.7

1025.3 1021.0 1016.7 1012.3 1007.8 1003.3 998.7 994.1 989.3 983.7

(8)

V ** = c + dx 2

(9)

Here, VCO2, V*, c, and d represent parameters derived from solving eqs 8 and 9. In Weiland’s model, a second order polynomial expression was applied to express the change in density data against temperatures for the pure amine.17 However, in this work a linear relationship as shown in eq 10 represented the data satisfactorily.

b

ρ/kg·m−3

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

b

V = x1V1 + x 2V2 + x3VCO2 + x1x 2V * + x 2x3V **

ρ/kg·m−3 = a + b·T /K

(10)

The a and b parameters in eq 10 are obtained from the intercept and slope of the regression, respectively. A temperature-density correlation published by Cheng et al.23 was utilized to determine the molar volume of pure water. Values of the fitted coefficients are indexed in Table 8 and incorporated Table 8. Parameters of the Density Correlation for CO2Loaded Aqueous 1DMA2P Solutions

Standard uncertainties u are u(x3) = ± 0.002, u(T) = ± 0.03 K, u(w) = ± 0.01. Instrument accuracy = ± 0.05 kg·m−3. The combined expanded uncertainty for density measurement Uc(ρ) is ±8.16 kg·m−3 (95 % level of confidence, k = 2). Standard deviation implies k = 1. bα = mol CO2/mol 1DMA2P. a

parameter

value

a b c d M2 VCO2

−0.982 1138.20 −1795.4 8111.1 103.16 88.601

V*

−15.976

as dotted lines in Figure 5. A parity plot comparing the measured and correlated density data is displayed in Figure 6.

Figure 6. Comparison between calculated and measured density data for CO2-loaded 1DMA2P solutions.

The maximum deviation between our experimental measurements and correlated data is 7.8 kg·m−3. Average absolute deviation values are 2.96 kg·m−3 and 3.86 kg·m−3 for 0.30 and 0.55 mass fractions, respectively. These values are small and within experimental error. It should also be noted that although the deviation between the regressed model and experimental data is small, it is observed that there is a systematic deviation between model and CO2 loading. Further improvements to the model might be achieved by taking into consideration additional parameters to represent the interaction between water and CO2 molecules in the system and possibly a ternary

Figure 5. Experimental density data of CO2-loaded 1DMA2P solutions at different CO2 loadings α/(mol CO2/mol 1DMA2P): 0.1 (■), 0.2 (●), 0.3 (▲), 0.4 (▼), 0.5 (◆). Panels A and B were constructed using data at 0.30 and 0.55 mass fractions, respectively. The correlation between densities and temperatures are shown as dotted lines.

F

DOI: 10.1021/je501126j J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

interaction parameter, and by fitting eq 9 to a second-order polynomial function. The other binary volume parameters could also be made concentration-dependent. However, one has to remember that fitting extra parameters into a model could result in a less physical significance of parameters in the model.

(6) 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. (7) Chowdhury, F. I.; Khan, M. A. R.; Saleh, M. A.; Akhtar, S. Volumetric Properties of Some Water + Monoalkanolamine Systems between 303.15 and 323.15 K. J. Mol. Liq. 2013, 182, 7−13. (8) Redlich, O.; Kister, A. T. Algebraic Representation of Thermodynamic Properties and the Classification of Solutions. Ind. Eng. Chem. 1948, 40, 345−348. (9) 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. (10) Hartono, A.; Svendsen, H. F. Density, Viscosity, and Excess Properties of Aqueous Solution of Diethylenetriamine (DETA). J. Chem. Thermodyn. 2009, 41, 973−979. (11) Zhang, F.-Q.; Li, H.-P.; Dai, M.; Zhao, J.-P.; Chao, J. P. Volumetric Properties of Binary Mixtures of Water with Ethanolamine Alkyl Derivatives. Thermochim. Acta 1995, 254, 347−357. (12) Lebrette, L.; Maham, Y.; Teng, T. T.; Hepler, L. G.; Mather, A. E. Volumetric Properties of Aqueous Solutions of Mono, and Diethylethanolamines at Temperatures from 5 to 80 °C II. Thermochim. Acta 2002, 386, 119−126. (13) Maham, Y.; Teng, T. T.; Hepler, L. G.; Mather, A. E. Volumetric Properties of Aqueous Solutions of Monoethanolamine, Mono-, and Dimethylethanolamines at Temperatures from 5 to 80 °C I. Thermochim. Acta 2002, 386, 111−118. (14) 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. (15) 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. (16) Hartono, A.; Mba, E. O.; Svendsen, H. F. Physical Properties of Partially CO2 Loaded Aqueous Monoethanolamine (MEA). J. Chem. Eng. Data 2014, 59, 1808−1816. (17) 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. (18) Jayarathna, S. A.; Jayarathna, C. K.; Kottage, D. A.; Dayarathna, S.; Eimer, D. A.; Melaaen, M. C. Density and Surface Tension Measurements of Partially Carbonated Aqueous Monoethanolamine Solutions. J. Chem. Eng. Data 2013, 58, 343−348. (19) Amundsen, T. G.; Oi, L. E.; Eimer, D. A. Density and Viscosity of Monoethanolamine + Water + Carbon Dioxide from (25 to 80) degrees C. J. Chem. Eng. Data 2009, 54, 3096−3100. (20) Muhammad, A.; Mutalib, M. I. A.; Murugesan, T.; Shafeeq, A. Density and Excess Properties of Aqueous N-Methyldiethanolamine Solutions from (298.15 to 338.15) K. J. Chem. Eng. Data 2008, 53, 2217−2221. (21) Mandal, B. P.; Kundu, M.; Bandyopadhyay, S. S. Density and Viscosity of Aqueous Solutions of (N-Methyldiethanolamine + Monoethanolamine), (N-Methyldiethanolamine + Diethanolamine), (2-Amino-2-methyl-1-propanol + Monoethanolamine), and (2Amino-2-methyl-1-propanol + Diethanolamine). J. Chem. Eng. Data 2003, 48, 703−707. (22) 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. (23) Cheng, S.; Meisen, A.; Chakma, A. Predict Amine Solution Properties Accurately. Hydrocarb. Process. 1996, 75, 81−84.

5. CONCLUSION Densities of unloaded and CO2-loaded aqueous 1DMA2P solutions were measured at different mass fractions and temperatures. In both cases we found that densities decrease with increasing temperatures and 1DMA2P mass fractions. The increase in mass fractions increases the thermal expansion coefficient values for unloaded aqueous 1DMA2P solutions albeit the relative change is smaller than for densities. The excess molar volumes calculated from density data of the unloaded 1DMA2P solutions were correlated by using a second order Redlich−Kister equation, and an average absolute deviation value of 0.3 kg·m−3 was calculated. In the case of CO2-loaded 1DMA2P solutions, density data at mass fractions of 0.30 and 0.55 were fitted using a model proposed by Weiland et al.17 The average absolute deviations between experimental and correlated densities are 2.96 kg·m−3 and 3.86 kg·m−3 for 0.30 and 0.55 mass fractions. Overall, low values of deviation suggest that good agreement exists between experimental and correlated data. The reported experimental data in this work should add to the existing knowledge on new amines for CO2 capture and can be employed in engineering estimations with a high confidence.

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Tel: +47 3557 4000. Fax: +47 3557 5002. Funding

The authors are grateful to The Research Council of Norway through CLIMIT Program (Grant No. 199890) for financial support. Notes

The authors declare no competing financial interest.

■ ■

ACKNOWLEDGMENTS We thank Tonje Warholm Thomassen for help with the density meter. REFERENCES

(1) Eimer, D. A. Gas Treating: Absorption Theory and Practice; Wiley: 2014. (2) Rochelle, G. T. Amine Scrubbing for CO2 Capture. Science 2009, 325, 1652−1654. (3) 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. (4) 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. (5) 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. G

DOI: 10.1021/je501126j J. Chem. Eng. Data XXXX, XXX, XXX−XXX