Equilibrium Solubility of CO2 in Aqueous Mixtures ... - ACS Publications

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Equilibrium Solubility of CO2 in Aqueous Mixtures of DEA and AEEA Abhinav Bajpai and Monoj Kumar Mondal* Department of Chemical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi-221005, Uttar Pradesh, India ABSTRACT: The present communication presents the new experimental CO2 solubility data in an aqueous mixture of diethanolamine (DEA) and (2aminoethyl)ethanolamine (AEEA) at CO2 concentrations in the inlet gas stream from (10.13 to 20.27) kPa and temperatures from (303.14 to 333.14) K. The aqueous (DEA + AEEA) mixtures of total concentrations were chosen from (0.92 to 3.22) mol·kg−1, and the mole fraction of AEEA in total amine was varied from 0.02 to 0.20. The findings point that the CO2 solubility in a fixed total concentration of amine mixture becomes more at a higher AEEA mole fraction in total amine with a constant temperature and CO2 concentration in the inlet gas stream. The CO2 solubility in the amine mixture falls with the rise in temperature but rises with an increase in CO2 concentration in the inlet gas stream. The highest amount of CO2 solubility in (DEA + AEEA) mixtures was observed as 0.74 mol CO2/mol absorbent with AEEA mole fraction in total amine of 0.2 at a 1.84 mol·kg−1 total concentration of amine mixture and 313.14 K. The result of this work is compared with some of the most studied amine mixtures available in the literature.

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INTRODUCTION Uninterrupted human activities have resulted in a significant increase of greenhouse gas concentrations in the environment over the past 200 years. By the year 2100, the average worldwide temperature may increase by (1.4 to 5.8) °C due to this increased amount of greenhouse gases as predicted by the various estimations of climate models.1 The excessive release of greenhouse gases has caused the serious environmental problems like global warming found in nature. CO2, amounting an almost more than 50 % major share in greenhouse gases, produces more than 60 % of the increased greenhouse effect at present. CO2 emissions mostly come from fossil-fuel based industries,2 such as coal-fired thermal power generation, petroleum and natural gas based energy industries, and various metallurgical processes, responsible for sustainable economic growth. India is the fifth largest CO2 contributor with approximately 5 % of the worldwide CO2 emissions, and the increasing emission trend is likely to be continued. The energy scenario of WEO 2009 forecasts that CO2 emissions in India will be more than 2.5 times that of the 2008 emission level by the year 2030 due to its economic growth.3 The majority of these emissions is attributed to heat and electricity generation, which showed an enhanced CO2 emission from 42 % in 1990 to 56 % in 2008. The transport sector contributes the smallest share of about 9 % of CO2 emissions in 2008 among other sectors. These growing trends of CO2 emissions raise the issue of low energy use and the need to invent efficient technologies for CO2 capture from contaminated gas streams released from industrial origins. Chemical absorption is a mature technology and mostly used in postcombustion thermal power plants where the CO2 concentration is very low (≤ 20 % by volume). This technology still has some limitations such as absorbent © 2013 American Chemical Society

degradation/losses, corrosion, high regeneration energy, and so forth, that reduce the overall performance of the process. The use of aqueous solutions of single amines or amine mixtures as an absorbent in CO2 capture based on chemical absorption is much more popular for commercial applications. Aqueous alkanolamine solutions have been commonly useful in CO2 absorption processes for over 60 years. The CO2 absorption in amine solution can be regarded as absorption with a chemical reaction where the equilibrium CO2 loading depends on both kinetics and thermodynamic of the process. In general primary and secondary amines show an enhanced absorption rate in comparison to tertiary amines. The reactivity for CO2 is in the order of primary > secondary > tertiary alkanolamines. To find more efficient absorbents for CO2 removal, use of mixtures of different alkalis is a new trend. The addition of 10 % 2-amino-2-methyl-1-propanol (AMP) in 30 % diethanolamine (DEA) solution in an aqueous mixture of DEA with AMP showed a 10 % increase in CO2 solubility.4 It was also observed in a 30 % aqueous mixture of DEA with Nmethyldiethanolamine (MDEA) that the CO2 solubility increased with increase in MDEA concentration. According to Mandal et al.5 the small addition of DEA into AMP solution enhanced CO2 absorption appreciably. Tan and Chen6 investigated the removal efficiency of CO2 in blend of AMP and monoethanolamine (MEA) mixed with piperazine (PZ) and found that the CO2 removal efficiency was 2 to 4 times compared to that without PZ in the mixture. Received: September 5, 2012 Accepted: April 26, 2013 Published: May 7, 2013 1490

dx.doi.org/10.1021/je3011776 | J. Chem. Eng. Data 2013, 58, 1490−1495

Journal of Chemical & Engineering Data

Article

outlet gas stream became same as that of inlet gas stream indicating equilibrium was achieved. After the equilibrium was established, the amount of CO2 absorbed in the liquid phase (reported as CO2 solubility) was measured by titrating the known amount of CO2 saturated liquid with 0.6 mol % of HCl solution.8 For checking the repeatability, minimum two CO2 loaded liquid samples after equilibrium was analyzed under fixed experimental condition, and the data were reproducible to within 0.5 %. The experimental uncertainties of the measurements of pressure, temperature, and CO2 concentration in liquid phase are 0.2 kPa, 0.1 K, and 0.5 %, respectively.

The most commonly used amines in industrial plants for CO2 absorption are alkanolamines such as MEA, DEA, and MDEA. The present work is based on the improvement on DEA based CO2 absorption. Since DEA has limited loading, it needs to be improved. (2-Aminoethyl)ethanolamine (AEEA) is an unhindered diamine and showed better CO2 loading capacities comparable to effective absorbents like PZ, AMP, and so forth. At a low conversion CO2, AEEA formed carbamate, and at a high conversion of CO2, it formed protonated carbamate.7−9 Two nitrogen atoms present in the AEEA structure can absorb 2 mol of CO2, so it is a very efficient activator for CO2 absorption. Because of it AEEA has been used as a loading promoter with many aqueous solutions of organic amines as well as inorganic absorbents in CO2 removal applications. In this work, new experimental solubility data of CO2 in the (DEA + AEEA) mixture has been reported. The solubility of CO2 in the (DEA + AEEA) mixture has been measured at temperatures (303.14 to 343.14) K, partial pressures (10.13 to 20.26) kPa, total concentrations of mixture (0.92 to 3.22) mol·kg−1, and AEEA mole fraction in total amine (0.02 to 0.20). The CO2 solubility result of the present study has been compared with the published data of the most investigated amine mixtures.

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RESULTS AND DISCUSSION The CO2 solubility was observed in the aqueous amine mixture of (DEA + AEEA) by varying the total concentration of mixture (CT) in the range (0.92 to 3.22) mol·kg−1 and AEEA mole fractions in total amine from 0.02 to 0.20 over the temperature range (303.14 to 343.14) K at a CO2 partial pressure ranging from (10.13 to 20.27) kPa. The experimental CO2 solubility data are registered in Tables 1 to 7. For observing the effect of Table 1. Experimental mCO2−X Data for the Aqueous (DEA + AEEA) Mixture at T = 313.14 K and pCO2 = 15.199 kPaa

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EXPERIMENTAL SECTION Materials. AEEA (SD Fine-Chem Limited, Mumbai, ≥ 99 % pure) and DEA (Sisco Researh laboratories Pvt. Ltd., Mumbai, ≥ 98 % pure) were used in the experiment without doing any purification process. The solutions were prepared using distilled water by weight. The desired CO2 concentration in the gas stream was prepared by mixing two gas streams, one from the CO2 cylinder (20 % CO2 by volume and rest N2) and the other from N2 cylinder with a 99.99 % purity in a gasmixing so-called simulation chamber. The volume of gas passed was recorded by wet gas flow meter. The CO2 gas analyzer (UNIPHS 225 p.m., 0 to 100 % CO2 measuring range) was used for CO2 analysis in the gas phase within ± 0.2 % accuracy by volume. A constant-temperature water bath (CE404, Narang Scientific Works Pvt. Ltd., New Delhi, India) ranging from (0 to 200) °C with ± 0.1 °C accuracy was used to fix the operating temperature. Apparatus and Procedure. The earlier experimental setup8 has been used to conduct the experiments in this work. The bubble column containing (DEA + AEEA) aqueous mixture was kept inside a water bath for maintaining constant temperature. A thermometer having 0.1 K subdivisions was used to measure both the temperatures of bath water and aqueous mixture of (DEA + AEEA) in the column. To initiate the experiment, the bubble column was filled first with a fixed amount of aqueous solution of the (DEA + AEEA) mixture. Experiments were performed at atmospheric pressure using CO2 and N2 mixtures with varying CO2 partial pressure in the range of (10.13 to 20.26) kPa. The gas stream before being fed to the bubble column was checked to ensure the desired CO2 composition in the inlet gas stream. After maintaining the constant temperature of the absorbent in the bubble column and ensuring the desired CO2 partial pressure, the gas stream was allowed to enter into the column and bubbled through the absorbent with minimum possible rate such that the bubbles were not collapsed during the up flow through the absorbent bed. The composition of CO2 in outlet gas stream was recorded by using CO2 analyzer for every 10 min time interval. The experimental run was continued until the CO2 composition in

mCO2/(molCO2/moltotal amine) CT/mol·kg−1 X

1.84

2.30

2.76

0.00 0.02 0.10 0.15 0.20

0.601 0.613 0.655 0.702 0.74

0.58 0.592 0.634 0.68 0.715

0.57 0.581 0.624 0.671 0.701

a

Standard uncertainties: AEEA mole fraction in total amine (X) = 0.0001; total (DEA + AEEA) mixture concentration (CT) = 0.0001 mol·kg−1; pressure (pCO2) = 0.2 kPa; temperature (T) = 0.1 K; CO2 solubility (mCO2) = 0.005.

AEEA mole fraction in amine mixture, three different total concentrations of the (DEA + AEEA) mixture were taken as (1.84, 2.30, and 2.76) mol·kg−1 for a constant temperature and inlet CO2 partial pressure of 313.13 K and 15.199 kPa, respectively. For these mole fraction of AEEA in total amine was taken as 0.02, 0.1, 0.15, 0.2 with changing proportion of concentration of DEA and AEEA. Figure 1 represents that the addition of AEEA is advantageous in the (DEA + AEEA) mixture regarding to CO2 loading. The CO2 loading has been increased with the increase in AEEA mole fraction in total amine for all three total concentrated mixtures with a negligible variation of removal. It is also observed that the CO2 loading is increased more in (1.84 to 2.76) mol·kg−1 with the AEEA addition. So, AEEA is beneficial when it is used as activator for the absorption of CO2 in the amine mixture. The comparison of the results for (DEA + AEEA) mixtures of present study with other DEA-based mixtures of earlier publications is shown in Figure 2. From Figure 2, it is clear that the present system has a higher CO2 solubility than (DEA + PZ) and (DEA + MDEA) mixtures. It has also been found from Figure 2 that CO2 solubility is at a maximum at 0.2 mole fraction of activator in total amine. For observing the influence of total amine mixture concentration, the temperature and CO2 partial pressure have 1491



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Table 2. Experimental mCO2−X Data with the Data of Other Studied Aqueous Amine Mixtures at T = 313.14 K and pCO2 = 15.199 kPaa (DEA + PZ)8

(DEA + AEEA) present work

(DEA + AMP)11

X

mCO2/(molCO2/moltotal amine)

X*


X**


0.02 0.05 0.10 0.20

0.613 0.655 0.702 0.74

0.02 0.05 0.10 0.20

0.549 0.58 0.61 0.656

0.02 0.05 0.10 0.20

0.528 0.544 0.592 0.622

a

Standard uncertainties: AEEA mole fraction in total amine (X) = 0.0001; pressure (pCO2) = 0.2 kPa; temperature (T) = 0.1 K; CO2 solubility (mCO2) = 0.005. Note: X*, PZ mole fraction;8 X**, AMP mole fraction.11

Table 3. Experimental mCO2−CT Data for the Aqueous (DEA + AEEA) Mixture at T = 313.14 K and pCO2 = 15.199 kPaa CT/mol·kg−1


0.92 1.38 1.84 2.30 2.76 3.22

0.789 0.762 0.74 0.721 0.704 0.697

Table 6. Experimental mCO2−T Data for the Aqueous (4 mass % DEA + 26 mass % AEEA) Mixture at pCO2 = 15.199 kPa and CT =1.84 mol·kg−1 a T/K


303.14 313.14 323.14 333.14 343.14

0.759 0.74 0.691 0.621 0.542

a

Standard uncertainties: total (DEA + AEEA) mixture concentration (CT) = 0.0001 mol·kg−1; pressure (pCO2) = 0.2 kPa; temperature (T) = 0.1 K; CO2 solubility (mCO2) = 0.005.

a

Table 4. Experimental mCO2−pCO2 Data for the Aqueous (DEA + AEEA) Mixture at T = 313.14 K and CT =1.84 mol·kg−1 a

Table 7. Experimental mCO2−T Data with the Data of Other Studied Aqueous Amine Mixtures at pCO2 = 15.199 kPaa

Standard uncertainties: total (DEA + AEEA) mixture concentration (CT) = 0.0001 mol·kg−1; pressure (pCO2) = 0.2 kPa; temperature (T) = 0.1 K; CO2 solubility (mCO2) = 0.005.


mCO2/(molCO2/moltotal amine) T/K

(4 mass % DEA + 26 mass % AEEA) present work

(2 mass % DEA + 28 mass % PZ)8

(1.5 mass % DEA + 28.5 mass % MDEA)10

303.14 313.14 323.14 333.14

0.759 0.74 0.691 0.621

0.678 0.656 0.589 0.53

0.449 0.425 0.402 0.391

X pCO2/kPa

0.02

0.10

0.15

0.20

10.13 12.67 15.20 20.27

0.587 0.601 0.613 0.629

0.626 0.643 0.655 0.676

0.671 0.689 0.702 0.723

0.699 0.722 0.74 0.764

a

Standard uncertainties: pressure (pCO2) = 0.2 kPa; temperature (T) = 0.1 K; CO2 solubility (mCO2) = 0.005.

a

Standard uncertainties: AEEA mole fraction in total amine (X) = 0.0001; total (DEA + AEEA) mixture concentration (CT) = 0.0001 mol·kg−1; pressure (pCO2) = 0.2 kPa; temperature (T) = 0.1 K; CO2 solubility (mCO2) = 0.005.

decrease in the CO2 solubility in the (DEA + AEEA) mixture. But at a high concentration range, there is a small decrease in CO2 solubility because of the smaller extent of reversion of carbamate to bicarbonate. The inlet CO2 partial pressure also plays an important role in CO2 absorption. To study its effect on the CO2 solubility, the inlet CO2 partial pressure has been taken in the range of (10.13 to 20.27) kPa at 313.14 K and 1.84 mol·kg−1 total

been taken as 313.14 K and 15.199 kPa, respectively, and the mole fraction of AEEA has been kept constant at 0.2 in total amine mixture of (DEA + AEEA). The observation of CO2 solubility is plotted with the total amine concentration in Figure 3. By observing the trends in Figure 3, it is evident that, with the increase in total concentration of amine mixture, there is a

Table 5. Experimental mCO2−pCO2 Data with the Data of Other Studied Aqueous Amine Mixtures at T = 313.14 Ka mCO2/(molCO2/moltotal amine) pCO2/kPa

(4 mass % DEA + 26 mass % AEEA) present work

(2 mass % DEA + 28 mass % PZ)8

(1.5 mass % DEA + 28.5 mass % DEA)10

(6 mass % DEA + 24 mass % AMP)11

10.13 12.67 15.20 20.27

0.699 0.722 0.74 0.764

0.618 0.637 0.656 0.676

0.35 0.392 0.425 0.523

0.524 0.57 0.622 0.634

a

Standard uncertainties: pressure (pCO2) = 0.2 kPa; temperature (T) = 0.1 K; CO2 solubility (mCO2) = 0.005. 1492



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Figure 1. CO2 solubility mCO2 in mixtures of DEA with AEEA as a function of AEEA mole fraction in total amine X at T = 313.14 K and pCO2 = 15.199 kPa for total (DEA + AEEA) mixture concentration CT of ■, 1.84 mol·kg−1; red ●, 2.30 mol·kg−1; green ▲, 2.76 mol·kg−1.

Figure 3. CO2 solubility mCO2 at a different total (DEA + AEEA) mixture concentration CT at T = 313.14 K, pCO2 = 15.199 kPa with AEEA mole fraction in total amine X of 0.2.

Figure 4. CO2 solubility mCO2 at various inlet partial pressures of CO2 in a 1.84 mol·kg−1 (DEA + AEEA) mixture with a AEEA mole fraction in total amine X of ■, 0.02; red ●, 0.10; green ▲, 0.15; blue ▼, 0.20 at T = 313.14 K.

Figure 2. CO2 solubility mCO2 in mixtures of DEA with various additives as a function of additive mole fraction X in total amine at T = 313.14 K and pCO2 = 15.199 kPa: red ●, DEA + PZ (Mondal8); ■, DEA + AMP (Seo and Hong11); green ▲, DEA + AEEA (this work).

concentration of amine mixture with th evarying mole fraction of AEEA in total amine from 0.02 to 0.20 (Figure 4). From Figure 4, it is observed that CO2 solubility is the increasing function of inlet CO2 partial pressure. The experimental results were also compared with the published data (Figure 5). Figure 5 shows that with the increase in inlet CO2 partial pressure the CO2 solubility also increases because it increases the interfacial mass transfer as a result of increase in driving force of the gas phase from bulk to interface. The experimental results of (DEA + AEEA) mixtures in the present investigation show a higher absorption capacity relative to the published results. Figure 6 shows the influence of temperature on CO2 solubility with varying temperature from (303.14 to 343.14) K at fixed values of the total concentration of the (DEA + AEEA) mixture, AEEA mole fraction in total amine mixture, and inlet partial pressure of CO2 as 1.84 mol·kg−1, 0.2, and 15.199 kPa, respectively. After observing Figures 6 and 7, it is concluded that CO2 solubility is decreased continuously while increasing the temperature and similar results were also reported by Mondal8 and Kundu and Bandyopadhyay.10 The

Figure 5. CO2 solubility mCO2 in various DEA mixtures as a function of the inlet partial pressure pCO2 at T = 313.14 K: blue ▼, DEA + AEEA (this work); green ▲, DEA + PZ (Mondal8); ■, DEA + AMP (Seo and Hong11); red ●, DEA + MDEA (Kundu and Bandyopadhyay10). 1493



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present (DEA + AEEA) mixture has a higher CO2 solubility than the other mixtures reported earlier with approximate similar conditions of temperature, pressure, and total amine concentration.

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CONCLUSIONS In aqueous (DEA + AEEA) mixtures of (1.84 to 2.76) mol·kg−1 total concentration at 15.199 kPa inlet CO2 partial pressure and 313.14 K, the CO2 solubility has been increased between 5 % and 30 % with an AEEA mole percent increase in the range of 2 % to 20 %. The effect of AEEA on CO2 solubility has been more pronounced at low amine concentrations. The CO2 solubility in a (DEA + AEEA) mixture has been an increasing function of inlet partial pressure of CO2 for the range of (10.13 to 20.27) kPa CO2 solubility has been observed decreasing in temperature range of (303.14 to 343.14) K. The result of CO2 solubility in the (DEA + AEEA) mixture has been found to be superior to other mixtures, namely, (DEA + AMP), (MDEA + PZ), and (DEA + MDEA), available in literature at a 15.199 kPa partial pressure of CO2 in inlet gas stream and a 313.14 K temperature.

Figure 6. CO2 solubility mCO2 with temperature T in a 1.84 mol·kg−1 (DEA + AEEA) mixture having a AEEA mole fraction in total amine of 0.2 at pCO2 = 15.199 kPa.

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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Tel.: +919452196638. Fax: + 91 542 2368092. Funding

The authors acknowledge the support and financial assistance provided by the Banaras Hindu University to undertake the work. Notes

The authors declare no competing financial interest.

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Figure 7. CO2 solubility mCO2 in various DEA-based mixtures with temperature T: ■, DEA + AEEA (this work); red ●, DEA + PZ (Mondal8); green ▲, DEA + MDEA (Kundu and Bandyopadhyay10).

REFERENCES

(1) Intergovernmental Panel on Climate Change. Summary for Policymakers. In Climate Change 2007: The Physical Science Basis, Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change; World Meteorological Organization/United Nations Environment Program: Geneva, 2007. (2) Lu, J. G.; Cheng, M.; Ji, Y.; Hui, Z. Membrane-based CO2 Absorption into Mixtureed Amine Solutions. J. Fuel Chem. Technol. 2009, 37, 740−746. (3) Energy Information Administration (EIA), 2008. International Energy Outlook; EIA: Washington, DC, 2008. (4) Murrieta-Guevara, F.; Rebolledo-Libreros, M. E.; RomeroMartinez, A.; Trejo, A. Solubility of CO2 in Aqueous Mixtures of Diethanolamine with Methyldiethanolamine and 2-Amino-2-methyl-1propanol. Fluid Phase Equilib. 1998, 150−151, 721−729.

decrease in CO2 solubility with increasing temperature may result as most of the reactions involved in CO2 capture by amines are reversible and the equilibria is governed by backward reaction with increasing temperature, and also the solubility of gases generally increases with the decrease in temperature. Table 8 reports the CO2 solubility in (DEA + AEEA) mixture of present investigation with the data of most studied amine mixtures by other workers. It has been noted that the

Table 8. Comparison of CO2 Solubility in Different Aqueous Amine Mixtures amine mixture

T/K

pCO2/kPa

CT/mol·kg−1


references

DEA+AEEA DEA+PZ DEA+AMP DEA+MDEA MDEA+PZ MDEA+PZ DEA+MDEA DEA+MDEA TIPA+PZ

313.14 313.14 313.14 313 313.14 303 313 313.15 313.14

15.199 15.199 15.199 15.199 15.199 15.6 15.199 15.199 15.199

1.84 1.88 1.87 1.83 1.97 3.45 1.83 1.83 2.02

0.74 0.656 0.622 0.506 0.497 0.506 0.425 0.376 0.225

present work Mondal8 Seo and Hong11 Benamor and Aroua12 Ali and Aroua15 Liu et al.13 Kundu and Bandyopadhyay10 Murrieta-Guevara et al.4 Daneshvar et al.14

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(5) Mandal, B. P.; Biswas, A. K.; Bandyopadhyay, S. S. Absorption of Carbon Dioxide into Aqueous Mixtures of 2-Amino-2-methyl-1propanol and Diethanolamine. Chem. Eng. Sci. 2003, 58, 4137−4144. (6) Tan, C.; Chen, J. Absorption of Carbon Dioxide with Piperazine and its Mixtures in a Rotating Packed Bed. Sep. Purif. Technol. 2006, 49, 174−180. (7) Mamun, S.; Dindore, V. Y.; Svendsen, H. F. Kinetics of the Reaction of Carbon Dioxide with Aqueous Solutions of 2-((2Aminoethyl) amino)ethanol. Ind. Eng. Chem. Res. 2007, 46, 385−394. (8) Mondal, M. K. Solubility of Carbon Dioxide in an Aqueous Mixture of Diethanolamine and Piperazine. J. Chem. Eng. Data 2009, 54, 2381−2385. (9) Zoghi, A. T.; Feyzi, F.; Zarrinpashneh, S. Investigation on the Effect of Addition of Amine Activators to Aqueous Solutions of NMethyldiethanolamine on the Rate of Carbon Dioxide Absorption. Int. J. Greenhouse Gas Control 2012, 7, 12−19. (10) Kundu, M.; Bandyopadhyay, S. S. Solubility of CO2 in Water + Diethanolamine + N-methyldiethanolamine. Fluid Phase Equilib. 2006, 248, 158−167. (11) Seo, D.; Hong, W. Solubilities of Carbon Dioxide in Aqueous Mixtures of Diethanolamine and 2-Amino-2-methyl-1-propanol. J. Chem. Eng. Data 1996, 41, 258−260. (12) Benamor, A.; Aroua, M. K. Modeling of CO2 Solubility and Carbamate Concentration in DEA, MDEA, and Their Mixtures Using the Deshmukh-Mather Model. Fluid Phase Equilib. 2005, 231, 150− 162. (13) Liu, H.; Zhang, C.; Xu, G. A Study on Equilibrium Solubility for Carbon Dioxide in Methyldiethanolamine-Piperazine-Water Solution. Ind. Eng. Chem. Res. 1999, 38, 4032−4036. (14) Daneshvar, N.; Moattar, M. T. Z.; Abdi, M. A.; Aber, S. Carbon Dioxide Equilibrium Absorption in the Multicomponent Systems of CO2 + TIPA + MEA + H2O, CO2 + TIPA + PZ + H2O, and CO2 + TIPA + H2O at Low CO2 Partial Pressures: Experimental Solubility Data, Corrosion Study, and Modeling with Artificial Neural Network. Sep. Purif. Technol. 2004, 37, 135−147. (15) Ali, B. S.; Aroua, M. K. Effect of Piperazine on CO2 Loading in Aqueous Solutions of MDEA at Low Pressure. Int. J. Thermophys. 2004, 25, 1863−1870.

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Equilibrium Solubility of CO2 in Aqueous Mixtures ... - ACS Publications

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