Densities of Partially Carbonated Aqueous Diethanolamine and

Article pubs.acs.org/jced

Densities of Partially Carbonated Aqueous Diethanolamine and Methyldiethanolamine Solutions Sanoja A. Jayarathna,† Deshaka A. Kottage,† Dag A. Eimer,†,‡ and Morten C. Melaaen*,†,‡ †

Telemark University College, Porsgrunn, Norway Tel-Tek, Porsgrunn, Norway

‡

ABSTRACT: Densities of carbon dioxide loaded (partially carbonated), aqueous diethanolamine (DEA) solutions and aqueous methyldiethanolamine (MDEA) solutions are measured within a temperature range from (293.15 to 423.15) K. The series of DEA and MDEA aqueous solutions cover a range of amine mass ratios from (0.5 to 0.8) and a range of CO2 loading from (0 to 0.5) mol CO2·mol amine−1. All of the data points are compared with the predictions of the model from Weiland et al., and data regression is performed to fit selected parameters of the model. Predictions from the model fitted in this work are compared with the data measured in this work. The capability of the fitted model to predict the densities of the partially carbonated aqueous DEA and MDEA solutions with amine mass ratios different from what is used in this work is analyzed.

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INTRODUCTION Chemical absorption is an efficient method for CO2 capture, especially from the gas streams with low CO2 concentrations.1−3 Aqueous alkanolamine solutions are widely used in the absorption−desorption process for the removal of CO2 from the gas streams. Industrially important alkanolamines for the absorption of CO2 are monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA). High concentration amine solutions are interesting since amine circulation can be reduced and energy can be saved. Physical properties like density, viscosity, and solubility of CO2 in such solutions are with great importance for further analysis of the use for CO2 capture as well as for the equipment design and related analysis via modeling and simulation. Density measurements of single alkanolamine solutions, mixed amine solutions, and activated amine solutions have been presented in literature.4−10 Published measurements of partially carbonated alkanolamine solutions are scarce though. This work presents a set of measurements covering high concentration DEA and MDEA aqueous solutions, with the range of mass ratio of amine in the aqueous amine solutions, r (MAmine/MAmine+Water) = (0.5 to 0.8), in the range of temperature, T = (293.15 to 423.15) K. The measured carbonated aqueous amine solutions cover a range of CO2 loading, α = (0 to 0.5) mol CO2·mol amine−1. Several correlations exist for the prediction of the densities of the aqueous amine solutions either single or mixed and CO2 loaded or unloaded.5,11 Neither of those correlations are able to make predictions to be in good agreement with the measurements made in this work. Parameter estimation of several selected parameters of a correlation from literature5 is performed as a part of this work to obtain good representation of the density of the high concentration solutions of partially © 2012 American Chemical Society

carbonated DEA and MDEA. The acceptability of the predictions from the correlation with the newly fitted parameters outside of the measurement range in this work is also analyzed.

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EXPERIMENTAL SECTION This section provides an insight to the procedures of sample preparation, sample analysis, and measurement performance. Sample descriptions of amines and CO2 are given in Table 1. Table 1. Chemical Sample Descriptions

a

chemical abbreviation

source

initial mole fraction

analysis method

CO2 DEA MDEA

AGA

0.999 0.99 0.98

GCa GCa

Gas−liquid chromatography.

Sample Preparation. Aqueous solutions of DEA and MDEA were prepared using degassed, purified water and the amines. Water purification and degassing were done using a Milli-Q integral water purification system and a rotary evaporator, respectively. Amines are used as received. Water and amines are measured using an analytical balance with an accuracy of ± 1·10−7 kg and mixed with the appropriate proportion to achieve the required mass ratios, r = (0.5 to 0.8), until they are completely mixed. The loaded amine samples were prepared by diluting an aqueous amine solution of selected mass ratio and high CO2 Received: May 11, 2012 Accepted: October 16, 2012 Published: October 31, 2012 2975

dx.doi.org/10.1021/je300530z | J. Chem. Eng. Data 2012, 57, 2975−2984

Journal of Chemical & Engineering Data

Article

Table 2. Densities, ρ, of Partially Carbonated DEA Solutions from T = (293.15 to 423.15) K and CO2 Loading, α/mol CO2·mol DEA−1, from (0.0 to 0.5) at Mass Ratios r = (0.5 to 0.8)a,b,c ρ/kg·m−3 (r = 0.5)

α mol CO2·mol amine

−1

293.15 K

303.15 K

313.15 K

323.15 K

333.15 K

343.15 K

353.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 α

1060.7 1070.9 1079.1 1088.2 1097.9 1106.8 1115.8 1125.5 1135.0 1144.3 1153.3

1055.5 1064.6 1073.9 1083.0 1092.7 1101.5 1110.5 1120.1 1129.6 1138.8 1147.6

1050.0 1059.0 1068.4 1077.5 1087.1 1096.0 1104.9 1114.4 1123.9 1133.1 1141.8

1044.1 1053.2 1062.6 1071.7 1081.3 1090.2 1099.1 1108.6 1118.0 1127.1 1135.8 ρ/kg·m−3 (r = 0.5)

1037.9 1047.1 1056.5 1065.6 1075.2 1084.1 1092.9 1102.4 1111.8 1120.9 1128.4

1031.4 1040.6 1051.2 1059.2 1068.8 1077.7 1086.6 1096.1 1105.2 1115.0 1122.5

1024.5 1033.9 1043.9 1052.6 1062.3 1071.2 1080.1 1089.4 1098.5 1107.9a 1116.4a

mol CO2·mol amine−1

363.15 K

373.15 K

383.15 K

393.15 K

403.15 K

413.15 K

423.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 α

1017.4 1026.8 1036.8 1045.6 1055.3 1064.2 1073.1 1082.4 1092.3 1101.0a 1109.4a

1010.0a 1019.6a 1029.7a 1038.5a 1048.3a 1057.2a 1066.0a 1075.5a 1084.7a 1093.5a 1101.8a

1002.2a 1011.9a 1022.0a 1030.8a 1040.7a 1049.4a 1058.4a 1067.9a 1077.0a 1085.7a

994.9a 1003.7a 1014.0a 1022.8a 1032.6a 1042.0a 1050.4a 1059.7a 1068.6a 1078.4a

985.6a 995.4a 1005.0a 1013.8a 1023.8a 1033.0a 1041.8a 1050.9a

976.7a 986.5a 996.1a 1005.0a 1014.7a 1023.5a 1032.1a

967.4a 977.3a 986.6a 996.4a 1004.7a

ρ/kg·m−3 (r = 0.6) −1

mol CO2·mol amine

293.15 K

303.15 K

313.15 K

323.15 K

333.15 K

343.15 K

353.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 α

1073.1 1083.9 1094.6 1105.4 1115.7 1127.4 1138.1 1149.6 1160.8 1171.9 1182.5

1067.4 1078.2 1088.9 1099.7 1110.0 1121.6 1132.4 1143.8 1155.0 1166.0 1176.6

1061.4 1072.2 1083.0 1093.8 1104.1 1115.8 1126.5 1137.9 1149.1 1160.0 1170.5

1055.2 1066.0 1076.8 1087.7 1098.0 1109.7 1120.4 1131.8 1142.9 1153.8 1164.3 ρ/kg·m−3 (r = 0.6)

1048.6 1059.0 1070.4 1081.4 1091.7 1103.4 1114.1 1125.5 1136.6 1147.4 1157.7

1041.9 1052.5 1063.8 1074.8 1085.1 1096.8 1107.6 1119.0 1130.1 1140.8 1151.2a

1034.7 1045.7 1056.7 1067.7 1078.8 1089.8 1100.9 1112.0 1123.0 1134.3a 1144.5a


363.15 K

373.15 K

383.15 K

393.15 K

403.15 K

413.15 K

423.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 α

1027.3 1038.5 1049.6 1060.6 1071.7 1082.9 1093.9 1105.6a 1116.6a 1127.3a 1137.4a

1020.0a 1031.3a 1042.5a 1053.8a 1064.9a 1076.1a 1087.2a 1098.3a 1109.2a 1119.9a 1129.8a

1012.1a 1023.5a 1034.8a 1046.1a 1057.3a 1068.5a 1079.5a 1090.7a 1101.5a 1112.0a

1003.9a 1015.5a 1026.8a 1038.7a 1049.4a 1060.5a 1071.6a 1082.6a 1093.2a

995.4a 1006.7a 1018.5a 1029.9a 1041.0a 1052.1a 1063.2a 1073.8a

986.6a 998.2a 1009.6a 1020.9a 1031.8a 1042.6a

977.4a 989.1a 1000.2a 1011.2a 1021.8a


293.15 K

303.15 K

313.15 K

323.15 K

333.15 K

343.15 K

353.15 K

0.00 0.05 0.10 0.15 0.20

1082.5 1094.5 1106.4 1118.4 1129.3

1076.5 1088.6 1100.6 1112.6 1123.5

1070.3 1082.5 1094.5 1106.5 1117.5

1064.0 1076.1 1088.2 1100.3 1111.3

1057.3 1069.6 1081.8 1093.9 1104.9

1050.5 1062.9 1075.1 1087.3 1098.4

1043.5 1055.9 1068.2 1080.5 1091.7

ρ/kg·m−3 (r = 0.7)

2976



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Table 2. continued ρ/kg·m−3 (r = 0.7)

α mol CO2·mol amine−1

293.15 K

303.15 K

313.15 K

323.15 K

333.15 K

343.15 K

353.15 K

0.25 0.30 0.35 0.40 0.45 0.50 α

1141.3 1153.2 1165.1 1177.4 1189.5 1201.2

1135.5 1147.5 1159.4 1171.6 1183.7 1195.3

1129.5 1141.5 1153.4 1165.6 1177.7 1189.3

1123.4 1135.4 1147.3 1159.6 1171.6 1183.1 ρ/kg·m−3 (r = 0.7)

1117.1 1129.1 1141.1 1153.3 1165.3 1176.8

1110.5 1122.6 1134.6 1146.0 1158.8 1170.9a

1103.9 1116.0 1128.0 1140.1 1152.6a 1164.0a


363.15 K

373.15 K

383.15 K

393.15 K

403.15 K

413.15 K

423.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 α

1036.1 1048.6 1061.0 1073.4 1084.7 1096.9 1109.1 1121.1 1133.6a 1145.6a 1156.8a

1028.9a 1041.4a 1054.0a 1066.4a 1077.8a 1090.1a 1102.2a 1114.3a 1126.3a 1138.2a 1149.3a

1020.9a 1033.6a 1046.2a 1058.8a 1070.2a 1082.5a 1094.6a 1106.7a 1118.6a 1130.3a

1012.7a 1025.6a 1038.3a 1050.9a 1062.4a 1074.7a 1086.8a 1098.4a 1110.4a

1004.2a 1017.2a 1030.0a 1042.6a 1053.8a 1066.4a 1078.6a 1088.6a

995.4a 1008.6a 1021.3a 1033.8a 1044.9a 1057.2a

986.4a 999.5a 1011.9a 1024.0a 1035.0a


293.15 K

303.15 K

313.15 K

323.15 K

333.15 K

343.15 K

353.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 α

1089.6 1103.4 1116.9 1130.9 1144.7 1158.7 1172.9 1186.8 1201.7 1214.7 1228.8

1083.6 1097.4 1110.9 1124.9 1138.6 1152.6 1166.9 1180.7 1195.6 1208.7 1222.7

1077.4 1091.2 1104.8 1118.8 1132.6 1146.6 1160.8 1174.7 1189.5 1202.5 1216.4

1070.9 1084.9 1098.5 1112.6 1126.4 1140.5 1154.7 1168.6 1183.4 1196.3 1210.2 ρ/kg·m−3 (r = 0.8)

1064.2 1078.3 1092.0 1106.1 1120.0 1134.2 1148.5 1162.4 1177.2 1190.1 1205.1a

1057.4 1071.6 1085.3 1099.5 1113.5 1127.7 1142.0 1156.0 1170.8 1183.6 1198.4a

1050.5 1064.6 1078.5 1092.7 1106.9 1121.0 1135.5 1149.4 1164.2a 1177.6a 1190.8a


363.15 K

373.15 K

383.15 K

393.15 K

403.15 K

413.15 K

423.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50

1043.1 1057.5 1071.4 1085.7 1099.9 1114.2 1128.5 1142.9a 1157.7a 1170.6a 1183.6a

1036.0a 1050.4a 1064.4a 1078.7a 1093.1a 1107.4a 1121.9a 1135.8a 1150.5a 1163.2a

1028.1a 1042.6a 1056.8a 1071.2a 1085.6a 1099.9a 1114.4a 1128.3a 1141.3a

1020.1a 1034.8a 1049.0a 1063.5a 1077.8a 1092.2a 1106.6a 1120.3a

1012.1a 1026.6a 1040.9a 1055.4a 1069.8a 1083.4a 1098.4a

1003.2a 1018.2a 1032.4a 1046.8a 1060.9a 1074.3a

995.4a 1009.2a 1023.1a 1037.0a

ρ/kg·m−3 (r = 0.8)

Data marked with the letter “a” are measured at 8·105 Pa, and the rest of the data are measured at 1·105 Pa. bStandard uncertainties u are u(α) = ± 0.005 mol CO2·mol DEA−1, u(r) = ± 0.0036, u(T) = ± 0.03 K (at P = 1·105 Pa), u(T) = ± 0.05 K (at P = 8·105 Pa), instrument accuracy = ± 0.05 kg·m−3 (at P = 1·105 Pa), instrument accuracy = ± 0.1 kg·m−3 (at P = 8·105 Pa). cThe combined expanded uncertainty Uc is Uc(ρ) = ± 3.38 kg·m−3 (level of confidence = 0.95, where k = 2). a

check the loading value and the amine mass ratio. A selected set of diluted samples were also sent through the titration analysis to check the accuracy of the sample preparation. The mass ratio analysis was done via titration of the preprepared samples with a 1 mol·L−1 HCl solution to find the equilibrium point. The samples used for titration were prepared by mixing a sample of 2 g from each prepared amine solution with deionized water until each sample became 100 cm3 in

loading (>0.5) with an unloaded amine solution in proper proportions to get the required CO2 loading values, α = (0 to 0.5) in the prepared samples. The high loaded amine solutions were prepared by bubbling CO2 gas through an unloaded amine solution of required mass ratio. The CO2 gas was used as received. Sample Analysis. The prepared high CO2 loaded aqueous amine solutions were analyzed using a titration method to 2977



Article

Table 3. Densities, ρ, of Partially Carbonated MDEA Solutions from T = (293.15 to 423.15) K and CO2 Loading, α/mol CO2·mol MDEA−1, from (0.0 to 0.5) at Mass Ratios r = (0.5 to 0.8)a,b,c ρ/kg·m−3 (r = 0.5)

α −1

mol CO2·mol amine

293.15 K

303.15 K

313.15 K

323.15 K

333.15 K

343.15 K

353.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 α

1045.8 1054.3 1062.6 1071.0 1079.2 1087.5 1095.6 1103.9 1112.3 1119.9 1127.1

1039.6 1048.0 1056.3 1064.6 1072.8 1081.1 1089.1 1097.4 1105.9 1113.4 1120.7

1033.0 1041.4 1049.7 1058.0 1066.2 1074.5 1082.5 1090.8 1099.2 1106.8 1114.1

1026.1 1034.6 1042.9 1051.2 1059.4 1067.6 1075.6 1084.0 1092.4 1100.0 1106.7 ρ/kg·m−3 (r = 0.5)

1018.9 1027.4 1035.7 1044.1 1052.3 1060.5 1068.6 1077.2a 1085.7a 1093.3a 1100.8a

1011.4 1019.9 1028.3 1036.6 1043.9 1053.5a 1061.6a 1070.0a 1078.4a 1086.1a 1093.6a

1003.5 1012.1 1020.5 1029.2a 1037.4a 1045.8a 1053.6a 1062.1a 1070.4a


363.15 K

373.15 K

383.15 K

393.15 K

403.15 K

413.15 K

423.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 α

995.3 1004.0 1012.6a 1021.1a 1029.3a 1037.6a 1045.6a 1054.0a

987.0a 995.8a 1004.1a 1012.6a 1020.8a 1029.0a 1036.9a 1045.2a

978.2a 986.9a 995.1a 1003.5a 1011.6a 1019.7a 1027.3a

968.9a 977.7a 985.8a 994.0a 1001.8a

959.3a 967.9a 975.9a

949.4a 957.7a 965.2a

939.1a 947.0a

mol CO2·mol amine

ρ/kg·m−3 (r = 0.6) −1

293.15 K

303.15 K

313.15 K

323.15 K

333.15 K

343.15 K

353.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 α

1052.6 1061.9 1071.2 1080.1 1089.3 1098.5 1107.7 1116.9 1126.1 1135.2 1144.9

1045.8 1055.1 1064.4 1073.3 1082.5 1091.8 1101.0 1110.1 1119.3 1128.5 1138.2

1038.6 1048.0 1057.4 1066.3 1075.5 1084.8 1094.0 1103.2 1112.4 1121.6 1131.4

1031.2 1040.7 1050.1 1059.1 1068.3 1077.6 1086.9 1096.1 1105.9a 1115.1a 1125.0a ρ/kg·m−3 (r = 0.6)

1023.6 1033.1 1042.6 1051.6 1060.9 1070.2 1079.5 1088.8 1098.6a 1107.8a 1117.8a

1015.6 1025.3 1034.8 1043.8 1053.7a 1063.1a 1072.5a 1081.7a 1091.1a 1100.3a

1007.4 1017.2 1026.7 1036.2a 1045.5a 1055.1a 1064.5a 1073.4a 1083.6a 1092.2a


363.15 K

373.15 K

383.15 K

393.15 K

403.15 K

413.15 K

423.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 α

998.9 1008.7 1018.5a 1027.8a 1037.1a 1046.5a 1055.9a 1064.7a

990.3a 1000.1a 1009.7a 1018.9a 1028.1a 1037.3a 1046.4a

981.2a 991.0a 1000.3a 1009.3a 1018.4a 1027.1a

971.8a 981.4a 990.4a 999.0a

962.1a 971.4a 979.6a

952.1a 960.9a 968.0a

941.9a 949.8a


293.15 K

303.15 K

313.15 K

323.15 K

333.15 K

343.15 K

353.15 K

0.00 0.05 0.10 0.15 0.20

1056.1 1066.6 1076.9 1087.4 1097.9

1048.8 1059.4 1069.8 1080.4 1091.0

1041.3 1052.0 1062.4 1073.1 1083.8

1033.6 1044.9 1054.9 1065.7 1076.3

1025.6 1036.6 1047.1 1057.9 1068.7

1017.4 1028.5 1039.1 1049.9 1061.1a

1009.0 1020.1 1030.7 1041.5a 1052.0a

ρ/kg·m−3 (r = 0.7)

2978



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Table 3. continued ρ/kg·m−3 (r = 0.7)

α mol CO2·mol amine−1

293.15 K

303.15 K

313.15 K

323.15 K

333.15 K

343.15 K

353.15 K

0.25 0.30 0.35 0.40 0.45 0.50 α

1108.5 1119.1 1128.2 1139.3 1149.2 1159.8

1101.6 1112.2 1122.0 1132.5 1142.4 1153.4

1094.4 1105.1 1114.8 1125.5 1135.6 1146.8a

1087.1 1097.8 1107.7 1117.4 1128.6a 1139.7a ρ/kg·m−3 (r = 0.7)

1079.4 1090.7a 1100.8a 1111.3a 1121.0a 1132.4a

1069.8a 1082.6a 1092.7a 1103.2a 1112.8a 1124.2a

1062.8a 1073.1a 1082.8a 1092.9a


363.15 K

373.15 K

383.15 K

393.15 K

403.15 K

413.15 K

423.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 α

1000.4 1012.1 1022.0a 1032.6a 1043.0a 1053.5a 1063.6a

991.8a 1002.7a 1012.8a 1023.1a 1033.1a

982.6a 993.3a 1002.9a

973.2a 983.4a 992.2a

963.7a 972.9a

953.7a 961.9a

943.6a 950.3a


293.15 K

303.15 K

313.15 K

323.15 K

333.15 K

343.15 K

353.15 K

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 α

1055.5 1067.0 1077.8 1089.7 1100.5 1113.5 1126.7 1139.9 1150.2 1162.2

1048.1 1059.7 1070.6 1082.5 1093.5 1106.4 1119.8 1132.9 1143.4 1155.7a 1167.7a

1040.5 1052.2 1063.1 1075.1 1086.2 1099.1 1112.5 1125.5a 1136.5a 1148.4a 1160.4a

1032.6 1044.5 1055.4 1067.5 1078.5 1092.6a 1104.8a 1117.7a 1128.7a

1024.6 1036.5 1047.5 1059.5 1070.9a 1084.5a 1096.6a

1016.4 1028.2 1039.1 1051.6 1062.4a 1075.8a 1087.8a

1007.9 1019.7 1030.7a 1042.4a 1053.0a 1065.8a

ρ/kg·m−3 (r = 0.8)

ρ/kg·m−3 (r = 0.8) −1

mol CO2·mol amine 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50

363.15 K

373.15 K

383.15 K

393.15 K

403.15 K

413.15 K

423.15 K

999.3 1010.8 1021.4a 1032.6a

990.8a 1001.7a 1011.4a

981.7a 991.9a 1000.5a

972.5a 981.4a

963.1a 969.9a

953.4a

943.5a

Data marked with the letter “a” are measured at 8·105 Pa, and the rest of the data are measured at 1·105 Pa. bStandard uncertainties u are u(α) = ± 0.005 mol CO2·mol MDEA−1, u(r) = ± 0.0038, u(T) = ± 0.03 K (at P = 1·105 Pa), u(T) = ± 0.05 K (at P = 8·105 Pa), instrument accuracy = ± 0.05 kg·m−3 (at P = 1·105 Pa), instrument accuracy = ± 0.1 kg·m−3 (at P = 8·105 Pa). cThe combined expanded uncertainty Uc is Uc(ρ) = ± 2.68 kg·m−3 (level of confidence = 0.95, where k = 2). a

the CO2 in the samples react with BaCl2 and precipitate as BaCO3, then cooled down in a water bath and filtered to collect the precipitate. Each collected precipitate was added into 100 cm3 of deionized water and then titrated with 0.1 mol·L−1 HCl solution until the mixture reached the equilibrium point. The mixture was then heated to remove all of the dissolved CO2 and back-titrated with 0.1 mol·L−1 NaOH solution to calculate the amount of excess HCl. Finally, the moles of HCl reacted with

total. The amount of HCl used in the titration was used to calculate the amount of amine presented in each sample and subsequently the mass ratio of the corresponding aqueous amine solution. The sample preparation for the loading analysis was performed by mixing about (0.5 to 1.0) g of the loaded amine solution with 50 cm3 each from 0.3 mol·L−1 BaCl2 and 0.1 mol·L−1 NaOH. Those samples were boiled for 5 min to let 2979



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Figure 1. Density of DEA from T = (293.15 to 423.15) K for selected CO2 loading: α mol CO2·mol DEA−1 values (a) at r = 0.6 and (b) at r = 0.8. △, □, and ○, for α = 0.05, 0.3, and 0.5 at 1·105 Pa; ▲, ■, and ●, for α = 0.05, 0.3, and 0.5 at 8·105 Pa.

Figure 2. Density of MDEA from T = (293.15 to 423.15) K for selected CO2 loading: α mol CO2·mol MDEA−1 values (a) at r = 0.5 and (b) at r = 0.7. △, □, and ○, for α = 0.0, 0.25, and 0.5 at 1·105 Pa; ▲, ■, and ●, for α = 0.0, 0.25, and 0.5 at 8·105 Pa.

BaCO3 precipitate was used to find the amount of CO2 in the corresponding partially carbonated aqueous amine sample and subsequently the CO2 loading value of the solution. Density Measurements. Densities of the partially carbonated aqueous amine solutions were measured using an Anton Paar densimeter with a low pressure cell (model DMA 4500) and a high pressure cell (model DMA HP). The DMA 4500 was calibrated using degassed water and air occasionally, but a density check was performed more frequently to check the validity of the previous calibration. The operation of DMA 4500 is limited to atmospheric pressure and 363.15 K of temperature, while DMA HP can be used at higher pressures and temperatures. The calibration of DMA HP was done using nitrogen and degassed water every time before the use of the machine. Both measuring cells are based on an oscillatory Utube method, and the accuracy of the measurements is very much dependent on the calibration of the equipment. Density measurements of the aqueous amine solutions in the range of T = (293.15 to 363.15) K were taken using the low pressure cell, DMA 4500. Bubble formation due to the evaporation of amines and water and desorption of CO2 was a challenge for using the low pressure cell for some aqueous amine solutions even below the temperature limit of the equipment. The high pressure cell, DMA HP, was used to do the measurements outside the temperature limit of the DMA 4500 up to 423.15 K and also for those samples where the bubbling was an issue in the low pressure cell. The DMA HP was used under a pressure of 8·105 Pa to retain the evaporation and desorption in the capillary U-tube.

■

• Density measurements of partially carbonated aqueous DEA solutions from T = (293.15 to 423.15) K for r = (0.5 to 0.8) and α = (0.0 to 0.5). • Density measurements of partially carbonated aqueous MDEA solutions from T = (293.15 to 423.15) K for r = (0.5 to 0.8) and α = (0.0 to 0.5). Density measurements of the DEA and MDEA solutions with r = 0.5, 0.6, 0.7, and 0.8 are given in Tables 2 and 3, respectively. Results presented in Tables 2 and 3 are a combination of measurements from the two density meters, DMA 4500 and DMA HP. Possible measurements at low temperatures up to the limit of the DMA 4500 or until bubble rising occurred in the same densimeter were done at the atmospheric pressure, 1·105 Pa. The rest of the results were taken at 8·105 Pa. Bubble formation was a problem for some samples at high temperatures even when the high pressure cell was in use. Measurements could not be taken for such samples, and those data points are given as blank cells in the corresponding tables. The transition from one density meter to the other has not made a deviation in the results, and this continuation of the measurements can be seen in Figure 1 for DEA and in Figure 2 for MDEA. The density of the partially carbonated aqueous DEA and MDEA solutions increases with increasing CO2 loading and decreases with increasing temperature. The density of the solutions at each loading and temperature shows an increase with increasing mass ratio. Some of the density measurements of the unloaded amine solutions from this work are compared with the literature data to demonstrate the accuracy of the measurements. Due to the limitation of the data available, measurements taken for loaded amine solutions could not be compared with literature data. The comparison of the data from this work for DEA and MDEA aqueous solutions with the literature data are presented

RESULTS AND DISCUSSION

Results obtained from this work are 2-fold: 2980



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Table 4. Comparison of the DEA Density Data from This Work with Literature Data ρ/kg·m−3 xDEAa 0.1463 0.1464 0.1509 0.2006 0.2045 0.2061 0.2855 0.2856 0.3008 0.4014 0.4067 0.4073 a

293.15 K b

1060.7 1060.3c

1073.1b 1072.3c 1082.2c 1082.5b

1089.6b 1090.4c

303.15 K

313.15 K

b

323.15 K

b

1055.5 1055.1c 1056.2d 1065.8d 1067.4b 1066.6c 1076.2c 1076.5b 1077.6d 1083.2d 1083.6b 1084.1c

b

1050.0 1049.5c 1050.6d 1059.7d 1061.4b 1060.6c 1069.9c 1070.3b 1071.2d 1076.8d 1077.4b 1077.7c

1044.1 1043.7c 1044.8d 1053.6d 1055.2b 1054.4c 1063.5c 1064.0b 1064.8d 1070.4d 1070.9b 1071.2c

333.15 K

343.15 K

353.15 K

b

1037.9 1037.4c

b

1031.4 1030.9c

1024.5b 1024.0c

1048.6b 1047.9c 1056.8c 1057.3b

1041.9b 1041.1c 1049.9c 1050.5b

1034.7b 1034.0c 1042.8c 1043.5b

1064.2b 1064.5c

1057.4b 1057.6c

1050.5b 1050.5c

xDEA = mole fraction of DEA. bThis work. cYang et al.12 dChowdhury et al.13

Table 5. Comparison of the MDEA Density Data from This Work with Literature Data ρ/kg·m−3 xMDEA

a

0.1293 0.1302 0.1313 0.1322 0.1332 0.1501 0.1823 0.1848 0.1859 0.1944 0.1992 0.2459 0.2526 0.2571 0.2608 0.2725 0.3658 0.3660 0.3715 0.3768 0.3981

293.15 K

303.15 K

313.15 K

323.15 K

333.15 K

343.15 K

353.15 K

363.15 K

1045.7c

1039.5c

1045.8b

1039.6b 1039.2e 1039.6f 1041.7g 1045.4c 1045.8b 1045.3e 1046.4f 1046.3g 1048.5g 1048.4e 1048.6c 1048.8b 1048.8f 1048.4e 1048.8f 1047.6c 1048.1b 1047.8g

1032.9c 1033.5d 1033.0b 1032.8e 1033.1f 1034.8g 1038.3c 1038.6b 1038.3e 1039.2f 1039.0g 1040.9g 1041.0e 1041.1c 1041.3b 1041.4f 1040.7e 1041.1f 1040.0c 1040.5b 1040.0g

1026.0c 1026.6d 1026.1b 1025.7e 1026.2f 1027.9g 1030.9c 1031.2b 1030.8e 1031.8f 1031.6g 1033.1g 1033.2e 1033.4c 1033.6b 1033.7f 1032.1e 1033.2f 1032.2c 1032.6b 1032.4g

1018.6c 1019.4d 1018.9b 1018.6e 1019.0f

1011.2c 1011.7d 1011.4b 1010.7e

1003.4c 1004.0d 1003.5b 1003.3e

995.2c 995.9d 995.3b

1023.2c 1023.6b 1023.1e 1024.1f

1015.3c 1015.6b 1015.2e

1007.1c 1007.4b 1007.1e

998.6c 998.9b

1025.4e 1025.4c 1025.6b 1025.9f 1024.8e 1025.2f 1024.3c 1024.6b

1017.4e 1017.2c 1017.4b

1008.9e 1008.8c 1009.0b

1016.8e

1008.3e

1016.2c 1016.4b

1007.6c 1007.9b

1052.3c 1052.6b

c

1055.9 1056.1b

1055.0c 1055.5b

1000.1c 1000.4b

999.0c 999.3b

xMDEA = mole fraction of MDEA. bThis work. cBernal-Garciá et al.14 dZúñiga-Moreno et al.15 eMaham et al.16 fMuhammad et al.17 gChowdhury et al.13 a

in Tables 4 and 5. Data produced in this work lie well within the range of the literature data. Model for Data Representation. A model to predict the density of partially carbonated amine solutions (for MEA, DEA, and MDEA) has been published by Weiland et al.5 This model predicts the density as a ratio of the average molecular weight to the mean molar volume of the solution. Predictions from the Weiland model with the existing parameters5 (fitted outside the mass ratio range used in this work) were found to be unsatisfactory for partially carbonated DEA and MDEA solutions in the range of r, T, and α used in this work. Comparison of the predictions from the Weiland model with some selected density measurements of DEA samples and MDEA samples are given in the Figures 3 and 4, respectively. Several selected parameters from the Weiland model are fitted against the measurements from this work with the

Figure 3. Density data and predictions of the correlation from Weiland et al.5 of DEA from T = (293.15 to 423.15) K for r = 0.6. ○, our data for α = 0.0; □, our data for α = 0.15; △, our data for α = 0.35; , α = 0.0 from ref 5; −−−, α = 0.15 from ref 5; ---, α = 0.35 from ref 5.

expectation of expanding the usability of the model for CO2 loaded aqueous DEA and MDEA solutions under high mass 2981



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Figure 5. Density of water at T = (298.15 to 423.15) K. ○, ref 12; , ref 11.

Figure 4. Density data and predictions of the correlation from Weiland et al.5 of MDEA from T = (293.15 to 423.15) K for r = 0.6. ○, our data for α = 0.0; □, our data for α = 0.15; △, our data for α = 0.35; , α = 0.0 from ref 5; −−−, α = 0.15 from ref 5; ---, α = 0.35 from ref 5.

improve the predictions of the density model for the partially carbonated aqueous MDEA solutions. Density values of pure MDEA measured in this work are given in Table 6. A comparison of the density predictions for pure MDEA with the new parameters, the data from this work and data from AlGhawas et al.19 and De-Guillo et al.20 are shown in Figure 6. All of the parameters to be used in the density model for CO2 loaded aqueous DEA and MDEA are listed in Table 7. The predictions from the newly fitted model for DEA and MDEA for r = 0.6 are given in Figures 7 and 8 along with the data from this work. The average absolute deviations (AAD) between the predictions and our data in kg·m−3 are 1.23, 1.49, 1.29, and 1.46 for DEA and 2.25, 2.42, 2.01, and 2.05 for MDEA at r = 0.5, 0.6, 0.7, and 0.8, respectively. The deviation of the predictions from the experimental data is within the acceptable error (maximum error in the predictions in 4.97 kg·m−3 for DEA and 9.6 kg·m−3 for MDEA). In an attempt to validate the newly fitted model and check its applicability outside of the mass ratio range used in this work, predictions from the models are compared with the data from Weiland et al.5 Comparisons of the data and predictions for DEA for r = (0.1 to 0.4) are given in Figure 9 and for MDEA from r = 0.3 and 0.4 are given in Figure 10. The average absolute deviations between the predictions of the model from this work, the Weiland model, and the experimental data presented by Weiland et al.5 are given in Table 8. The deviation between the predictions from the model fitted in this work and the experimental data is small and negligible for engineering calculations. Experimental Uncertainties. The uncertainty of the density measurements of CO2 loaded aqueous amine solutions arises as a combination of the uncertainties of temperature measurements, mass ratio, CO2 loading, and the measuring instrument itself. The accuracy for the temperature readings, U(T), is given for the instruments as ± 0.03 K for DMA 4500 and ± 0.05 K for DMA HP. The maximum gradient of density against temperature, ∂ρ/∂T, is 0.66 kg·m−3·K−1 and 0.88 kg·m−3·K−1 at 1·105 Pa and 0.74 kg·m−3·K−1 and 0.91 kg·m−3·K−1 at 8·105 Pa for DEA and MDEA samples, respectively. This corresponds an uncertainty in ρ, (∂ρ/∂T)·ΔT, of ± 0.0198 kg·m−3 and ± 0.0264 kg·m−3 at 1·105 Pa and 0.0370 kg·m−3 and 0.0455 kg·m−3 at 8·105 Pa for DEA and MDEA, respectively. Uncertainties of the properties of the samples were found by averaging the error values (difference between the expected value and the measured value for α and r) of the prepared samples. The uncertainty of the mass ratios, U(r), and the gradient ∂ρ/∂r, were found to be ± 0.0036 and 256 kg·m−3 for DEA and ± 0.0038 and 157 kg·m−3 for MDEA. The resulting uncertainty in the measurements, (∂ρ/∂r)·Δr, is ± 0.9216

ratios, up to r = 0.8. The structure of the model is given below by eqs 1 and 2. n

ρ=

∑ j = 1 (xj·Mj) Vs

(1)

3

Vs =

∑ (Vj·xj) + xj = 2·xj = 3·V * + xj = 1·xj = 3·V ** j=1

(2)

Here eq 1 comes from the basic definitions of the density of a solution. The symbols ρ, x, M, and Vs are the density, mole fraction, molar weight, and mean molar volume of the solution. The symbol V represents the molar volume of pure components and the species CO2, H2O, and amine are represented by j = 1, 2, and 3, respectively. Note that the molar volume of CO2 is to represent the dissolved CO2 and it is different from the component’s pure component value.12 Molar volume associated with the interactions between the amine and CO2 and the amine and H2O are given by V** and V*. Molar volumes associated with the interactions between the species (V* and V**) and the molar volume of CO2 (VCO2) were estimated using the data from this work via linear data regression (with the method of least-squares). VCO2 and V* are found as constants, and V** is found as a function of the amine mole fraction, given by eq 3, V ** = d + e·xj = 3

(3)

where d and e are coefficients and x is the mole fraction of species j. The molar volume of H2O was introduced using the density predictions from a correlation that has been published by Cheng et al.11 A comparison of the density predictions from Cheng’s correlation with the density values of pure water obtained from the International Association for the Properties of Water and Steam (IAPWS)18 is given in Figure 5. Densities of the pure amines needed for the computation of the molar volumes are given by Weiland et al.5 as functions of temperature. The structure of the temperature function of density is given by eq 4, ρ /(kg·m−3) = [a ·(T /K)2 + b ·(T /K) + c]·103

(4)

where a, b, and c are coefficients and T is the temperature. The temperature functions for density by Weiland et al.5 have been obtained by using the data from Al-Ghawas et al.19 and De-Guillo et al.20 The parameters of the density function of pure MDEA were fitted with the measurements taken in this work (with a root-mean-square-error: rmse of 0.13 kg·m−3) to 2982



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Table 6. Density of Pure MDEAa,b,c,d,e T/K ρ/kg·m−3 T/K ρ/kg·m−3

293.15 1039.90 363.15 986.00

303.15 1032.40 373.15 978.28a

313.15 1024.90 383.15 970.22a

323.15 1017.20 393.15 962.03a

333.15 1009.50 403.15 953.71a

343.15 1001.70 413.15 945.29a

353.15 993.90 423.15 936.81a

Data marked with the letter “a” are measured at 8·105 Pa, and the rest of the data are measured at 1·105 Pa. b(∂ρ/∂T) = ± 0.79 kg·m−3. cStandard uncertainties u are u(T) = ± 0.03 K (at P = 1·105 Pa), u(T) = ± 0.05 K (at P = 8·105 Pa), instrument accuracy = ± 0.05 kg·m−3 (at P = 1·105 Pa), instrument accuracy = ± 0.1 kg·m−3 (at P = 8·105 Pa). dThe combined expanded uncertainty Uc is Uc(ρ) = ± 0.11 kg·m−3 (at P = 1·105 Pa) and ± 0.22 kg·m−3 (at P = 8·105 Pa). eThe level of confidence for Uc = 0.95, where k = 2. a

Figure 6. Density of pure MDEA from T = (288.15 to 423.12) K. ∗, this work; ●, ref 19; ○, ref 20; , this work; ---, ref 5.

Figure 7. Density of DEA from T = (293.15 to 423.15) K at r = 0.6. ●, α = 0.0; ○, α = 0.05; ■, α = 0.1; □, α = 0.15; ▲, α = 0.2; ×, α = 0.25; △, α = 0.3; +, α = 0.35; ⧫, α = 0.4; ◊, α = 0.45; ▼, α = 0.5; , model prediction.

kg·m−3 for DEA and ± 0.5966 kg·m−3 for MDEA. The uncertainty of the loading, U(α), was found to be ± 0.005 for both DEA and MDEA. The gradient ∂ρ/∂α, was found as 282 kg·m−3 and 240 kg·m−3 for DEA and MDEA, respectively. The corresponding uncertainty, (∂ρ/∂α)·Δα, is ± 1.41 kg·m−3 for DEA and ± 1.20 kg·m−3 for MDEA. The instrument accuracy for DMA 4500 is given as ± 0.05 kg·m−3 and for DMA HP is given as ± 0.1 kg·m−3. The overall uncertainty of ρ, U(ρ), was calculated by combining the partial uncertainties reported in this section with a root sum of square method and found to be ± 1.69 kg·m−3 for DEA and ± 1.34 kg·m−3 for MDEA. The combined expanded uncertainty of the density measurements, Uc(ρ), was found as ± 3.38 kg·m−3 for DEA and ± 2.68 kg·m−3 for MDEA.

Figure 8. Density of MDEA from T = (293.15 to 423.15) K at r = 0.6. ●, α = 0.0; ○, α = 0.05; ■, α = 0.1; □, α = 0.15; ▲, α = 0.2; ×, α = 0.25; △, α = 0.3; +, α = 0.35; ⧫, α = 0.4; ◊, α = 0.45; ▼, α = 0.5; , model prediction.

■

CONCLUSIONS Densities of the CO2 loaded aqueous DEA and MDEA solutions ranging from mass ratios r = (0.5 to 0.8) at temperatures T = (293.15 to 423.15) K have been measured. An increase in the density with increasing CO2 loading and a decrease in the density with increasing temperature were observed at each mass ratio. The model presented by Weiland et al.5 was used to correlate the density data. The average absolute deviation between the predictions and measurements in kg·m−3 are 1.23, 1.49, 1.29, and 1.46 for DEA and 2.25, 2.42, 2.01, and 2.05 for MDEA at r = 0.5, 0.6, 0.7 and 0.8, respectively. The fitted model for estimating the density values of partially carbonated aqueous DEA and MDEA solutions constitute a

Figure 9. Density of DEA at 298.15 K for r = 0.1, 0.2, 0.3, and 0.4. All of the data are from Weiland et al.5 ○, r = 0.1; ●, r = 0.2; □, r = 0.3; ■, r = 0.4; , this work; −-−, predictions from ref 5.

Table 7. Parameters of the Density Correlation for Partially Carbonated DEA and MDEA a

b

c

d

e

M

DEA MDEA

−6.9129(−7) −3.973(−7) VCO2

−2.0663(−4) −5.066(−4) V*

1.21708 1.222

64.1419(−6) 66.4594(−6)

−93.8186(−6) −76.3351(−6)

105.14(−3) 119.17(−3)

DEA MDEA

−3.1029(−6) −5.6956(−6)

−2.5776(−6) −4.9779(−6) 2983



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(5) 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. (6) Amararene, F.; Balz, P.; Bouallou, C.; Cadours, R.; Lecomte, F.; Mougin, P.; Richon, D. Densities of Water + Diethanolamine + Methanol and Water + N-Methyldiethanolamine + Methanol at Temperatures Ranging from (283.15 to 353.15) K. J. Chem. Eng. Data 2003, 48, 1565−1570. (7) Ahmady, A.; Hashim, M. A.; Aroua, M. K. Density, viscosity, physical solubility and diffusivity of CO2 in aqueous MDEA + [bmim][BF4] solutions from 303 to 333 K. Chem. Eng. J. 2011, DOI: 10.1016/j.cej.2011.06.059. (8) Maham, Y.; Teng, T. T.; Hepler, L. G.; Mather, A. E. Densities, Excess Molar Volumes, and Partial Molar Volumes for Binary Mixtures of Water with Monoethanolamine, Diethanolamine, and Triethanolamine from 25 to 80 °C. J. Solution Chem. 1994, 23, 195−205. (9) Rinker, E. B.; Oelschlager, D. W.; Colussi, A. T.; Henry, K. R.; Sandall, O. C. Viscosity, Density, and Surface Tension of Binary Mixtures of Water and N-Methyldiethanolamine and Water and Diethanolamine and Tertiary Mixtures of These Amines with Water over the Temperature Range 20−100 °C. J. Chem. Eng. Data 1994, 39, 392−395. (10) Rebolledo-Libreros, M. E.; Trejo, A. Density and Viscosity of Aqueous Blends of Three Alkanolamines: N-Methyldiethanolamine, Diethanolamine, and 2-Amine-2-methyl-1-propanol in the range of (303 to 343) K. J. Chem. Eng. Data 2006, 51, 702−707. (11) Cheng, S.; Meisen, A.; Chakma, A. Predict amine solution properties accurately. Hydrocarbon Process 1996, 75, 81−84. (12) Yang, F.; Wang, X.; Liu, Z. Volumetric properties of binary and ternary mixtures of bis(2-hydroxyethyl)amine with water, methanol, ethanol from (278.15 to 353.15) K. Thermochim. Acta 2012, 533, 1−9. (13) Chowdhury, F. I.; Akhtar, S.; Saleh, M. A. Densities and excess molar volumes of some diethanolamines. Phys. Chem. Liq. 2009, 47, 638−652. (14) Bernal-García, J. M.; Ramos-Estrada, M.; Iglesias-Silva, G. A.; Hall, K. R. Densities and Excess Molar Volumes of Aqueous Solutions of n-Methyldiethanolamine (MDEA) at Temperatures from (283.15 to 363.15) K. J. Chem. Eng. Data 2003, 48, 1442−1445. (15) Zúñiga-Moreno, A.; Galicia-Luna, L. A.; Bernal-Garcia, J. M.; Iglesias-Silva, G. A. Densities, Excess Molar Volumes, Isothermal Compressibilities, and Isobaric Thermal Expansivities of the NMethyldiethanolamine (1) + Water (2) System at Temperatures between (313 and 363) K and Pressures up to 20 MPa. J. Chem. Eng. Data 2007, 52, 1988−1995. (16) Maham, Y.; Teng, T. T.; Mather, A. E.; Hepler, L. G. Volumetric properties of (water + diethanolamine) systems. Can. J. Chem. 1995, 73, 1514−1519. (17) 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. (18) Harvey, A. H. Thermodynamic Properties of Water; NISTIR 5078; NIST: Boulder, CO, 1998. (19) Al-Ghawas, H. A.; Hagewiesche, D. P.; Ruiz-Ibanez, G.; Sandall, O. C. Physicochemical Properties Important for Carbon Dioxide absorption in Aqueous Methyldiethanolamine. J. Chem. Eng. Data 1989, 34, 385−391. (20) DiGuillo, R. M.; Lee, R. J.; Schaeffer, S. T.; Brasher, L. L.; Teja, A. S. Densities and Viscosities of the Ethanolamines. J. Chem. Eng. Data 1992, 37, 239−242.

Figure 10. Density of MDEA at 298.15 K for r = 0.3 and 0.4. ●, r = 0.3 from ref 5; ○, r = 0.4 from ref 5; , this work; −-−, predictions from ref 5.

Table 8. Comparison of the Predictions from the Correlation Fitted in this Work and Correlation by Weiland et al.5 with Density Data outside the Mass Ratio, r, Range Considered in the Present Work r = 0.1 predictions from present work predictions from Weiland correlation

predictions from present work predictions from Weiland correlation a

r = 0.2

r = 0.3

r = 0.4

AADa for ρ/kg·m−3 of DEA 1.42 2.01 1.60 2.85 1.53 1.52 1.29 2.07 r = 0.3 r = 0.4 AAD for ρ/kg·m−3 of MDEA 3.12 4.45 2.61 3.26

AAD = average absolute deviation.

satisfactory representation with errors that would be negligible for engineering applications. The applicability of the fitted model outside the measurement conditions used in the present work was analyzed by using the data published by Weiland et al.5 The applicability was found to be satisfactory for lower mass ratios than those used in the current work.

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Phone: +47 3557 5286. Fax: +47 3557 5001. Funding

The authors would like to thank the Norwegian Research Council and Statoil for financial support. Notes

The authors declare no competing financial interest.

■ ■

ACKNOWLEDGMENTS The assistance from Van Khanh Tong is gratefully acknowledged. REFERENCES

(1) Lia, L.; Chen, B. Review of CO2 absorption using chemical solvents in hollow fiber membrane contactors. Sep. Purif. Technol. 2005, 41, 109−122. (2) Mandal, S. B. P.; Biswas, A. K.; Bandyopadhyay, S. S. Absorption of carbon dioxide into aqueous blends of 2-amino-2-methyl-1propanol and diethanolamine. Chem. Eng. Sci. 1996, 58, 4137−4144. (3) Singh, P.; Niederer, J. P. M.; Versteeg, G. F. Structure and activity relationships for amine based CO2 absorbents-I. Int. J. Greenhouse Gas Control 2007, 1, 5−10. (4) Amundsen, T. G.; Øi, L. E.; Eimer, D. A. Density and Viscosity of Monoethanolamine + Water + Carbon Dioxide from (25 to 80) °C. J. Chem. Eng. Data 2009, 54, 3096−3100. 2984


Densities of Partially Carbonated Aqueous Diethanolamine and

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