Equilibrium Solubility of CO2 in Aqueous Blend of 2-(Diethylamine

Article pubs.acs.org/jced

Cite This: J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Equilibrium Solubility of CO2 in Aqueous Blend of 2‑(Diethylamine)ethanol and 2‑(2-Aminoethylamine)ethanol Shailesh Kumar and Monoj Kumar Mondal* Department of Chemical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, Uttar Pradesh 221005, India ABSTRACT: New experimental CO2 solubility data at equilibrium in an aqueous blend of 2-(diethylamino)ethanol (DEEA) and (2-aminoethyl) ethanolamine (AEEA) have been illustrated for the concentration of CO2 in the inlet gas stream ranging from 10.132 to 20.265 kPa and aqueous amine blend temperature ranging from 303.14 to 333.14 K. Total concentrations of aqueous blend were taken in the range of 1.0−3.0 kmol/m3 and mole fraction of AEEA in total amine blend in the range of 0.02−0.20. Experiments were carried out in a semibatch operated laboratory scale gas−liquid bubbling absorber, and analysis of liquid phase CO2 as a saturated liquid was done by titration method. The equilibrium CO2 solubility in DEEA + AEEA blend was found to be a maximum at the value of 0.843 mol CO2/mol amine with AEEA mole fraction in total amine of 0.2 at 1 kmol/m3 total concentration of amine mixture and 303.14 K. New solubility data of CO2 in the present work was compared with existing literature data. An empirical correlation was developed from experimental CO2 solubility data as a function operating variables in the studied range.

■

noncyclic diamine 2-(2-aminoethylamine)ethanol (AEEA)7,8 which have been used as an activator for CO2 capture.9 Primary and secondary alkanolamines react with CO2 to form more stable carbamates, and these require high heat for desorption leading to high solvent regeneration cost. The sterically hindered amines form less stable carbamate due to a large group attached to the nitrogen atom. So, it has limited CO2 loading capacity of 0.5 mol of CO2 per mol of amine.10 But, tertiary amine cannot form carbamates with CO2 which facilitates the CO2 hydrolysis reaction forming bicarbonates as a final product with the CO2 loading capacity of 1.0 mol of CO2 per mol of amine.11 Also, tertiary amines are more preferred than primary and secondary amines due to high absorption capacity and require a less amount of heat during regeneration.12 But, due to slow reaction rate of tertiary amine with CO2, it requires the addition of other amines as an activator such as a primary amine, secondary amine, cyclic amine, and polyamines for enhancing the overall CO2 absorption performance. Particularly, DEEA as a novel tertiary amine shows better absorption performance than MDEA as a conventional tertiary amine.12,13 Also, it can be prepared from renewable sources as an agriculture products/residue and it also has a good potential for CO2 capture from process gas stream.14,15 The polyamine AEEA is a potential absorbent because it has high absorption rate, high CO2 cyclic capacity, high values of second-order reaction rate, and lower regeneration energy,7 but it may not be efficient for CO2 capture individually because it was revealed to show degradation behavior. So, AEEA may be used as an activator

INTRODUCTION In recent years, global warming and its potential effect on climate change are the serious environmental issues caused by anthropogenic emission of CO2 into the atmosphere and its major contribution of approximately 60% in enhanced greenhouse effect.1 The fossil fuel-based thermal power plant is one of the major anthropogenic sources of CO2 emissions worldwide.2 The other important sources for CO2 emission are iron and steel plants, cement industries, natural gas treatment plants, chemical and petrochemical manufacturing process, etc. Global carbon emissions from fossil fuels increased by 16 times from 1900 to 2008 and by about 1.5 times between 1990 and 2008.3 So, for the removal of CO2 from industrial process gas streams, various capture and separation technologies of CO2 are available. Several separation technologies for CO2 removal from gas streams are physical absorption, chemical absorption, adsorption, cryogenic, and membrane separation. Among these, the removal of CO2 from power plant flue gas using chemical absorption technology is preferred the most because CO2 can separate from the exhaust gas stream to a very low concentration. Currently, the method of absorption with amine-based chemical absorbents is most mature and has been commercially used for postcombustion CO2 capture in a fossil-fuel based thermal power plant.4,5 The different promising categories of alkanolamines used for capturing CO2 are such as primary amines such as monoethanolamine (MEA) and diglycolamine (DGA), secondary amines such as diethanolamine (DEA) and di-isopropanolamine (DIPA), tertiary amines such as N-methyl diethanolamine (MDEA) and triethanolamine (TEA), and sterically hindred amines such as 2-amino-2-methyl-1-propanol (AMP), etc.6 Also, another popular category of amines are cyclic diamine piperazine (PZ) and © XXXX American Chemical Society

Received: June 14, 2017 Accepted: March 21, 2018

A

DOI: 10.1021/acs.jced.7b00544 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Figure 1. Schematic diagram of the experimental setup: (1) CO2 gas cylinder, (2) N2 gas cylinder, (3) gas-flow rota meter, (4) gas mixing chamber, (5) stainless steel valves, (6) water bath, (7) bubbling absorber, (8) thermometer, (9) moisture absorber column, (10) flue gas analyzer, and (11) exhaust.

only.8 The reactivity for CO2 with alkanolamine is in the order of polyamine > cyclic amine > primary > secondary > tertiary.16 Although the absorption of CO2 in single DEEA has been widely studied by various researchers to measure CO2 solubility as well as absorption heat and modeling of vapor−liquid equilibrium data in the DEEA-H2O system,17−20 recently, for a greater improvement of the CO2 capture performance, a mixture of DEEA as a base solvent and AEEA as an activator has gained new research interest due to advantages of both amines. Many researchers have investigated, for CO2 capture, performance parameters in terms of absorption capacity, absorption rate, absorption heat, absorption flux, absorption coefficient, and reaction rate constant of CO2, etc. in several DEEA-based aqueous blend systems such as DEEA + N-methyl-1,3-diaminopropane (MAPA),21,31 DEEA + PZ,22−24,28,31 DEEA + MEA,25,29−31 DEEA + 1,4-butanediamine (BDA),26 DEEA + N-ethyl-ethanolamine (EAE), 14,15,27,31 DEEA + 1,6-hexamethyldiamine (HMDA),28 DEEA + diethylenetriamine (DETA),31 DEEA + triethylene tetramine (TETA),31 DEEA + AMP,31 DEEA + DEA,31 and DEEA + AEEA.28,31 Although, a little information is available on equilibrium CO2 solubility (loading) in the DEEA + AEEA blend, it requires more data at different operating conditions for rational design and operation in a gas separation unit for CO2 capture process in coal-based thermal power plant. Also, for the design and operation of the absorption−desorption columns for CO2 capture process, detailed knowledge of CO2 capture performance parameters are required, but the solubility of CO2 in amine blends is extremely important due to its prime steps design parameter for the determination of absorption capacity and its major role in the selection of any novel potential solvents. So, the present work is based on the improvement of CO2 absorption in an aqueous blend of DEEA and AEEA. The main purpose of this work is to study the CO2 solubility in an aqueous blend of DEEA and AEEA, at different operating conditions, because CO2 is present in the exhaust gas stream emitted from the power plant and the concentration of CO2 in the gas stream exhibits less than 20% by volume at atmospheric pressure. Therefore, the CO2 equilibrium solubility in DEEA + AEEA blends has been determined at an absorbent blend concentration in the range of 1−3 kmol/m3, a temperature range of 303.14−333.14 K, a CO2 partial pressure range of 10.132− 20.265 kPa, and an AEEA mole fraction in total amine ranging

from 0.02 to 0.20. The present studied experimental solubility data of CO2 in this blend have also been compared with available literature data.

■

EXPERIMENTAL SECTION Materials. The analytical reagent (AR) grade chemicals, DEEA and AEEA were purchased from Sisco Research Laboratory Pvt. Ltd., Mumbai. The DEEA + AEEA blend solutions were prepared at room temperature using double distilled water without any purification to various working concentrations as per the requirement. The CO2 simulated gas stream of desired concentration (10 to 20% by volume) was prepared in the gas simulation chamber by mixing gas streams from two cylinders (one cylinder containing 20% CO2 with balance N2 and another cylinder containing 99.99% N2). The volume of gas was measured by gas flow rotameter. The infrared flue gas analyzer (model Gas Board-3800P; Wuhan Cubic Optoelectronics Co. Ltd., Wuhan, China; with CO2 ranges of 0−100% by volume) was used for the gas phase CO2 analysis, with an accuracy of ±0.1%. A constant-temperature water bath (model CE404, Narang Scientific Works Pvt. Ltd., New Delhi, India) was used to set the operating temperature of the amine blend (273 to 473 K) within a minute variation of ±0.1 K. Others chemicals (NaOH, BaCl2· 2H2O, HCl) were analytical reagent (AR) grade used for analysis of CO2 in the liquid phase. Apparatus and Procedures. The experimental setup described in our previous publication10,32 was used in the present work with some modification for the measurement of CO2 solubility in an aqueous blend of DEEA and AEEA. A schematic diagram of the experimental setup has been shown in Figure 1. This setup is divided into three parts: first, preparation of simulated CO2 gas stream; second, absorption of gases in absorber; and third, analysis of liquid phase gas stream. The borosilicate glass gas−liquid contactor as bubbling absorber containing 100 mL of aqueous blend of DEEA and AEEA was placed inside the water bath, with temperature set to the desired point. Thermometers with subdivisions of 0.1 K were used to measure both the water bath and the liquid temperature inside the absorber. First, N2 gas stream was purged through the absorber for approximately 10 min for removal of trace gases which is present initially. Then, a fixed concentration of simulated CO2 gas stream was passed through gas flow rotameter with minimum flow rate of B



Article

approximately 0.5 dm3/min inside absorber and maintained continuous flow of gas with nondisturbance of bubbles at the upper layer of the liquid. After, a regular interval of time (10 min), the outlet gas stream concentration coming out from absorber through the moisture absorber column was analyzed by the infrared flue gas analyzer, and this procedure was continued until the concentrations of CO2 gas stream in the inlet and outlet was nearly the same, indicating that the liquid was saturated. Then, the equilibrium CO2 loading in the liquid phase was measured by the titration method with HCl (6 M) solution using phenolphthalein indicator followed by methyl orange indicator until the end point was reached.33 At a given temperature and pressure, at least two aliquot samples were taken to check the reproducibility, and the data were found to be reproducible to within 1%. The temperature was controlled within ±0.1 K from 303.15 to 333.15 K, and the total pressure was monitored for each run with an uncertainty of 0.01 kPa from 10.133 to 20.265 kPa.

Figure 2 shows the change in the liquid phase CO2 concentration with respect to absorption time for different mole fraction

■

RESULTS AND DISCUSSION The new CO2 solubility in an aqueous blend of DEEA and AEEA was measured for total blend concentrations (CT) in the range of (1.0−3.0) kmol/m3, mole fraction of AEEA (X) in the total blend ranging from 0.02 to 0.20, aqueous DEEA + AEEA blend temperature in the range of 303.14−333.14 K and CO2 partial pressures in the range of 10.13- 20.26 kPa. The experimental data of CO2 solubility in the DEEA + AEEA + H2O ternary system are reported in Table 1, whereas the CO2 solubility (loading) was

Figure 2. Variation of the CO2 solubility αCO2 with absorption time for different mole fraction of AEEA in total amine (X) of ▲, 0.20; ■, 0.10; and ⧫, 0.02, at CT = 2 kmol/m3 and pCO2 = 20.265 kPa.

of AEEA in a fixed concentration of total amine blend. The influence of AEEA mole fraction on CO2 solubility was investigated by varying the mole fraction of AEEA in the aqueous blend from 0.02 to 0.20 with changing proportions of amine blend for a total blend concentration of 2 kmol/m3. For a fixed AEEA mole fraction with a particular concentration of amine blend, the CO2 absorbed amount increases with absorption time and then remains constant which reveals that no more amount of CO2 is dissolved in this blend and the solution becomes completely saturated to achieve equilibrium. Figure 3 shows the variation

Table 1. Experimental Data on the Solubility of CO2 in Aqueous DEEA + AEEA Blend run

X

CT (kmol/ m3)

T (K)

pCO2 (kPa)

αCO2 (mol CO2/mol total amine)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

0.02 0.02 0.02 0.1 0.1 0.1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2

1 2 3 1 2 3 1 2 3 1 1 1 1 1 2 2 2 2 2 1 1 1 1 2 2 2 2

313.14 313.14 313.14 313.14 313.14 313.14 313.14 313.14 313.14 313.14 313.14 313.14 313.14 313.14 313.14 313.14 313.14 313.14 313.14 303.14 313.14 323.14 333.14 303.14 313.14 323.14 333.14

20.265 20.265 20.265 20.265 20.265 20.265 20.265 20.265 20.265 10.133 12.666 15.199 17.732 20.265 10.133 12.666 15.199 17.732 20.265 20.265 20.265 20.265 20.265 20.265 20.265 20.265 20.265

0.494 0.446 0.412 0.664 0.584 0.521 0.815 0.789 0.699 0.601 0.659 0.706 0.803 0.815 0.572 0.614 0.683 0.782 0.789 0.843 0.815 0.738 0.613 0.832 0.789 0.707 0.586

Figure 3. CO2 solubility αCO2 with different AEEA mole fraction in total amine X for total amine concentration CT of ⧫, 1 kmol/m3; ■, 2 kmol/m3; ▲, 3 kmol/m3, at T = 313.14 K and pCO = 20.265 kPa. 2

of CO2 solubility with AEEA mole fraction ranging from 0.02 to 0.20, for different amine blend concentrations in the range of 1−3 kmol/m3. Further from Figure 3, it can be clearly seen that the solubility of CO2 increases with increasing value of AEEA mole fraction in the total amine blend, and maximum value of CO2 solubility was observed at an AEEA mole fraction of 0.2. The enhancement of CO2 solubility in the liquid by blending with AEEA can be explained by the fact that AEEA possesses primary and secondary amino groups, resulting in increasing CO2 absorption.

expressed as the number of moles of CO2 absorbed per mole of total amine blend. C



Article

Figure 4 shows the influence of DEEA + AEEA blend concentration on the CO2 solubility at a temperature of 313.14 K, CO2

Figure 6. CO2 solubility αCO2 with partial pressure of CO2 at T = 313.14 K in 2 kmol/m3 amine blend with AEEA mole fraction in total amine of 0.2. Figure 4. CO2 solubility αCO2 with different total amine concentration CT at T = 313.14 K and pCO2 = 20.265 kPa, for X = 0.2.

Figure 7 shows the influence of temperature on CO2 solubility in the DEEA + AEEA blend over the temperature range

partial pressure of 20.265 kPa, and AEEA mole fraction of 0.2. From Figure 4 it is observed that there is decrease in CO2 solubility with an increase in amine blend concentration because at higher concentration a smaller extent of reversion of carbamate to bicarbonate can occur. The CO2 partial pressure in the inlet gas stream conjointly plays a serious role in acidic gas absorption. Its impact on the CO2 solubility was studied in an exceedingly 2.0 kmol/m3 DEEA + AEEA blend with an AEEA mole fraction of 0.20 at 313.14 K for CO2 partial pressures varying in the range of 10.199−20.265 kPa. From Figure 5, it is clearly seen that the CO2 partial pressure has

Figure 7. Variation of the CO2 solubility αCO2 with absorption time at various temperatures T (K) in a 2 kmol/m3 amine blend having an AEEA mole fraction in total amine of 0.2.

(303.14 to 333.14) K. In this regards, CO2 partial pressure in the gas stream, total blend concentration, and AEEA mole fraction within the blend were 20.265 kPa, 2.0 kmol/m3, and 0.2, respectively. From Figures 7 and 8, the solubility of CO2 decreases with increasing temperature, in agreement with information reported by Kundu and Bandyopadhyay34 and Mondal.10 The reactions between CO2 and amines in the absorption process are reversible in nature and as the temperature is increased then the gas−liquid equilibrium shifts in the backward direction. Also, at higher temperatures, natural desorption of CO2 takes place, and then the solubility of acidic gases typically decreases with increasing temperature. Maximum CO2 solubility according to numerous authors for various amine blends are given in Table 2. It has been observed that the present amine blend as a mixture of DEEA and AEEA have a higher solubility value than the other amine blends within the literature. An empirical CO2 solubility correlation was proposed to correlate total concentration of amine blend, mole fraction of

Figure 5. Variation of the CO2 solubility αCO2 with absorption time at various inlet partial pressures of CO2 in a 2 kmol/m3 amine blend with AEEA mole fraction in a total amine of 0.2.

little effect on CO2 solubility between the variation of 10.199− 12.63 kPa and 17.732−20.265 kPa. The CO2 solubility increases from (0.48 to 0.78) mol of CO2 per mole of total amine blend as the CO2 partial pressure increases from (10.133 to 20.265) kPa. Figure 6 shows that the acidic gas CO2 solubility increases with increasing CO2 partial pressure in the inlet gas stream as a result of increasing gas-phase mass transfer due to a rise of driving force existing in the gas phase from the bulk to the gas liquid interface. D



Article

or [S] = [A]−1 [B]

(2)

After solving the matrix, the correlation constants were obtained. These constants are a1 = 0.01163 mol CO2 mol amine−1; a2 = 3.2 × 10−2 mol CO2 mol amine−1 m3 kmol−1; a3 = 3.1 × 10−5 mol CO2 mol amine−1; a4 = 4.1 × 10−5 mol CO2 mol amine−1 kPa−1; a5 = 3.2 × 10−4 mol CO2 mol amine−1 K−1; a6 = 1.4 × 10−3 mol CO2 mol amine−1 m6 kmol−2; a7 = 3.8 × 10−4 mol CO2 mol amine−1; a8 = 4.7 × 10−6 mol CO2 mol amine−1 kPa−2; a9 = 3 × 10−6 mol CO2 mol amine−1 K−2. The calculated values of modeling results were plotted against experimental results as shown in Figure 9. The R2 value obtained

Figure 8. CO2 solubility αCO2 with temperature in 2 kmol/m3 amine blend having AEEA mole fraction of 0.2 at 20.265 kPa.

AEEA in total amine blend, CO2 partial pressure in inlet gas stream, and temperature of amine blend based on the experimental results. The correlation in the following form was taken to calculate CO2 solubility in the aqueous blend of DEEA and AEEA: S = a1 + a 2C T + a3X + a4pCO + a5T + a6C T 2 + a 7X2 2

+ a8pCO 2 + a 9T 2

(1)

2

3

where CT is total concentration of amine blend in kmol/m , X is mole fraction of AEEA in total amine blend, T is temperature of amine blend in K, and pCO2 is inlet partial pressure of CO2 in the gas stream in kPa. Then, the eq 1 in matrix form was solved as given below: ⎛ a11 a12 a13 a14 a15 a16 a17 a18 a19 ⎞ ⎛ s1 ⎞ ⎛ 0 ⎞ ⎜a a a a a a a a a ⎟ ⎜ s ⎟ ⎜ ⎟ ⎜ 21 22 23 24 25 26 27 28 29 ⎟ ⎜ 2 ⎟ ⎜ 0 ⎟ ⎜ a31 a32 a33 a34 a35 a36 a37 a38 a39 ⎟ ⎜ s3 ⎟ ⎜ 0 ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ a41 a42 a43 a44 a45 a46 a47 a48 a49 ⎟ ⎜ s4 ⎟ ⎜ 0 ⎟ ⎜ a51 a52 a53 a54 a55 a56 a57 a58 a59 ⎟ × ⎜ s5 ⎟ = ⎜ 0 ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ a61 a62 a63 a64 a65 a66 a67 a68 a69 ⎟ ⎜ s6 ⎟ ⎜ 0 ⎟ ⎜a a a a a a a a a ⎟ ⎜ s ⎟ ⎜0⎟ ⎜ 71 72 73 74 75 76 77 78 79 ⎟ ⎜ 7 ⎟ ⎜ ⎟ ⎜ a81 a82 a83 a84 a85 a86 a87 a88 a89 ⎟ ⎜ s8 ⎟ ⎜ 0 ⎟ ⎜ ⎟ ⎜ ⎟ ⎝ a 91 a 92 a 93 a 94 a 95 a 96 a 97 a 98 a 99 ⎠ ⎝ s9 ⎠ ⎝ 0 ⎠

Figure 9. Plot between calculated and experimental CO2 solubility αCO2 for all data analyzed.

from the result was found to be 0.992. However, the proposed CO2 solubility correlation was found to be effective for total amine blend concentration in the range of 1−3 kmol/m3, AEEA mole fraction in total amine blend in the ranges of 0.02−0.20, CO2 partial pressure in the range of 10.132−20.265 kPa, and amine blend temperature in the range of 303.14−333.14 K.

■

CONCLUSIONS The amount of CO2 absorbed varies with absorption time; it show a similar nature in the plot of all operating parameters such as AEEA mole fraction in total amine, amine blend concentration, CO2 partial pressure, and temperature. At the initial stage, absorption of CO2 takes place very rapidly within 0 to 120 min. It then becomes very low leading to the formation of a

The above matrix form may be written as [A][S] = [B]

Table 2. Comparison of CO2 Solubility Data in Various Aqueous Mixtures of Amines operating conditions amine mixture

CT (kmol/m3)

T (K)

pCO2 (kPa)

αCO2(mol CO2/mol total amine)

ref

DEEA + AEEA DEEA + AEEA DEEA DEEA + MEA DEEA + PZ DEA + AEEA MDEA + DEA MDEA + PZ MDEA + MAPA

1 1 2.58 2.58 2 + 0.5 2 2 2

303 313 313 313 303 303 313 313 313

20.27 20.27 20 20 5.80 20.27 20.00 15.20

0.843 0.815 0.457 0.531 0.69 0.74 0.696 0.75 0.743

this work this work Luo et al.29 Luo et al.29 Sutar et al.28 Bajpai and Mondal33 Kundu and Bandopadhyay34 Ali and Aroua35 Arshad et al.36

E



Article

(11) Albo, J.; Alvarez-Guerra, M.; Castaño, P.; Irabien, A. Towards the Electrochemical Conversion of Carbon Dioxide into Methanol. Green Chem. 2015, 17, 2304−2324. (12) 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 (24), 8323−8331. (13) Puxty, G.; Rowland, R.; Allport, A.; Yang, Q.; Bown, M.; Burns, R.; Maeder, M.; Attalla, M. Carbon Dioxide Post-combustion Capture: a Novel Screening Study of the Carbon Dioxide Absorption Performance of 76 Amines. Environ. Sci. Technol. 2009, 43, 6427−6433. (14) Vaidya, P. D.; Kenig, E. Y. A Study on CO2 Absorption Kinetics by Aqueous Solutions of N, N-Diethylethanolamine and N-Ethylethanolamine. Chem. Eng. Technol. 2009, 32, 556−563. (15) Vaidya, P. D.; Kenig, E. Y. Absorption of CO2 into Aqueous Blends of Alkanolamines Prepared from Renewable Resources. Chem. Eng. Sci. 2007, 62, 7344−7350. (16) Rayer, A. V.; Sumon, K. Z.; Henni, A.; Tontiwachwuthikul, P. Kinetics of the Reaction of Carbon Dioxide with Cyclic Amines Using the Stopped-Flow Technique. Energy Procedia 2011, 4, 140−147. (17) Xu, Z.; Wang, S.; Qi, G.; Trollebø, A. A.; Svendsen, H. F.; Chen, C. Vapor Liquid Equilibria And Heat of Absorption of CO2 in Aqueous 2-(Diethylamino)-Ethanol Solutions. Int. J. Greenhouse Gas Control 2014, 29, 92−103. (18) Arshad, M. W.; Fosbøl, P. L.; von Solms, N. V.; Svendsen, H. F.; Thomsen, K. Equilibrium Solubility of CO2 in Alkanolamines. Energy Procedia 2014, 51, 217−223. (19) Monteiro, J. G.M.-S.; Pinto, D. D.D.; Zaidy, S. A.H.; Hartono, A.; Svendsen, H. F. VLE Data and Modelling of Aqueous N,NDiethylethanolamine (DEEA) Solutions. Int. J. Greenhouse Gas Control 2013, 19, 432−440. (20) Luo, X.; Chen, N.; Liu, S.; Rongwong, W.; Idem, R. O.; Tontiwachwuthikul, P.; Liang, Z. Experiments and Modeling of VaporLiquid Equilibrium Data in DEEA-CO2-H2O System. Int. J. Greenhouse Gas Control 2016, 53, 160−168. (21) Liebenthal, U.; Pinto, D. D. D.; Monteiro, J.G.M.-S.; Svendsen, H. F.; Kather, A. Overall Process Analysis and Optimisation for CO2 Capture from Coal Fired Power Plants based on Phase Change Solvents Forming Two Liquid Phases, GHGT11; Energy Procedia: Kyoto, Japan, 2013. (22) Vaidya, P. D.; Kenig, E. Y. Acceleration of CO2 Reaction with N, N-diethylethanolamine in Aqueous Solutions by Piperazine. Ind. Eng. Chem. Res. 2008, 47, 34−38. (23) Konduru, P. B.; Vaidya, P. D.; Kenig, E. Y. Kinetics of Removal of Carbon Dioxide by Aqueous Solutions of N, N-diethylethanolamine and Piperazine. Environ. Sci. Technol. 2010, 44, 2138−2143. (24) Fu, D.; Wang, L.; Mi, C.; Zhang, P. Absorption Capacity and Viscosity for CO2 Capture Process using high Concentrated PZ-DEAE Aqueous Solution. J. Chem. Thermodyn. 2016, 101, 123−129. (25) Fu, D.; Wang, L.; Zhang, P.; Mi, C. Solubility and Viscosity for CO2 Capture Process using MEA Promoted DEAE Aqueous Solution. J. Chem. Thermodyn. 2016, 95, 136−141. (26) Xu, Z.; Wang, S.; Chen, C. Kinetics Study on CO2 Absorption with Aqueous Solutions of 1, 4-Butanediamine, 2-(Diethylamino)ethanol, and Their Mixtures. Ind. Eng. Chem. Res. 2013, 52, 9790−9802. (27) Chen, P. C.; Liao, C. C. A Study on CO2 Absorption in Bubble Column Using DEEA/EEA Mixed Solvent. Int. J. Eng. Prac. Res. 2014, 3 (4), 78. (28) Sutar, P. N.; Vaidya, P. D.; Kenig, E. Y. Activated DEEA Solutions for CO2 Capture-A Study of Equilibrium and Kinetic Characteristics. Chem. Eng. Sci. 2013, 100, 234−241. (29) Luo, X.; Liu, S.; Gao, H.; Liao, H.; Tontiwachwuthikul, P.; Liang, Z. An Improved Fast Screening Method for Single and Blended Aminebased Solvents for Post-combustion CO2 Capture. Sep. Purif. Sep. Purif. Technol. 2016, 169, 279−288. (30) Conway, W.; Bruggink, S.; Beyad, Y.; Luo, W.; Melián-Cabrera, I.; Puxty, G.; Feron, P. CO2 Absorption into Aqueous Amine Blended Solutions containing Monoethanolamine (MEA), N, N-dimethylethanolamine (DMEA), N,N-diethylethanolamine (DEEA) and 2-amino-2methyl-1-propanol (AMP) for Post-combustion Capture Processes. Chem. Eng. Sci. 2015, 126, 446−454.

carbonated saturated solution to achieve gas−liquid equilibrium. Further, more and more dissolution of CO2 in the blend takes place due to the presence of two amino groups in AEEA, it enhances the CO2 absorption corresponding to a higher CO2 loading. The maximum solubility of CO2 in the amine blend is observed at a 0.2 mole fraction of AEEA in the total amine. The total time elapsed to achieve equilibrium varies from 480 to 600 min depending on the concentration of amine blend and operating parameters. The solubility of CO2 in DEEA + AEEA blend increases with increasing concentration of CO2 in the gas phase but decreases as temperature rises. Also, the CO2 solubility in the present blend is greater than the other published data in the field. The proposed empirical CO2 solubility correlation exhibits a good relationship with experimental data for all operating parameters. Therefore, the present amine blend is more feasible and has a greater potential for the removal of CO2 from flue gas emitted from coal-fired thermal power plants.

■

AUTHOR INFORMATION

Corresponding Author

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

Monoj Kumar Mondal: 0000-0002-4544-7127 Funding

The authors thank Indian Institute of Technology (Banaras Hindu University) and Ministry of Human Resource Development (MHRD), India, for providing necessary help and financial support to carry out the present work. Notes

The authors declare no competing financial interest.

■

REFERENCES

(1) Metz, B.; Davidson, O.; Bosch, P.; Dave, R.; Meyer, L. Climate Change 2007-Mitigation of Climate Change; Working Group III Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change; Cambridge University Press: Oxford, U.K., 2007. (2) Adams, D.; Davison, J. Capturing CO2; IEA Greenhouse Gas R&D Programme, 2007. (3) Boden, T. A.; Marland, G.; Andres, R. J. Global, Regional, and National Fossil-Fuel CO2 Emissions; Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy: Oak Ridge, Tenn., U.S.A, 2010. (4) Tontiwachwuthikul, P.; Idem, R.; Gelowitz, D.; Liang, Z. H.; Supap, T.; Chan, C. W.; Sanpasertparnich, T.; Saiwan, C.; Smithson, H. Recent Progress and New Development of Post-combustion Carboncapture Technology Using Reactive Solvents. Carbon Manage. 2011, 2 (3), 261−263. (5) Rochelle, G. T. Amine Scrubbing for CO2 Capture. Science 2009, 325, 1652−1654. (6) Kohl, A. L.; Nielsen, R. B. Gas Purification, 5th ed.; Gulf Publishing: Houston, TX, 1997. (7) Ma’mun, S.; Svendsen, H. F.; Hoff, K. A.; Juliussen, O. Selection of New Absorbents for Carbon Dioxide Capture. Energy Convers. Energy Convers. Manage. 2007, 48, 251. (8) Aronu, U. E.; Svendsen, H. F.; Hoff, K. A.; Juliussen, O. Solvent Selection for Carbon Dioxide Absorption. Energy Procedia 2009, 1, 1051−1057. (9) Bindwal, A. B.; Vaidya, P. D.; Kenig, E. Y. Kinetics of Carbon Dioxide Removal by Aqueous Diamines. Chem. Eng. J. 2011, 169, 144− 150. (10) Mondal, M. K. Solubility of Carbon Dioxide in an Aqueous Blend of Diethanolamine and Piperazine. J. Chem. Eng. Data 2009, 54, 2381− 2385. F



Article

(31) Gao, H.; Xu, B.; Liu, H.; Liang, Z. Effect of Amine Activators on Aqueous N, N-Diethylethanolamine Solution for Post-combustion CO2 Capture. Energy Fuels 2016, 30, 7481−7488. (32) Balsora, H. K.; Mondal, M. K. Solubility of CO2 in Aqueous TSP. Fluid Phase Equilib. 2012, 328, 21−24. (33) Bajpai, A.; Mondal, M. K. Equilibrium Solubility of CO2 in Aqueous Mixtures of DEA and AEEA. J. Chem. Eng. Data 2013, 58, 1490−1495. (34) Kundu, M.; Bandyopadhyay, S. S. Solubility of CO2 in Water + Diethanolamine + N-methyldiethanolamine. Fluid Phase Equilib. 2006, 248, 158−167. (35) 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. (36) 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.

G


Equilibrium Solubility of CO2 in Aqueous Blend of 2-(Diethylamine

Recommend Documents