Article pubs.acs.org/EF
Single Process for CO2 Capture and Mineralization in Various Alkanolamines Using Calcium Chloride Murnandari Arti,†,‡ Min Hye Youn,† Ki Tae Park,† Hak Joo Kim,† Young Eun Kim,† and Soon Kwan Jeong*,†,‡ †
Green Energy Process Laboratory, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea ‡ University of Science and Technology Korea, 217 Gajeong-ro, Yuseong-gu, Daejeon 305-350, Republic of Korea ABSTRACT: To replace the thermal regeneration method of absorbent in the CO2 capture system, a novel method of CO2 absorption−mineralization was investigated. In this study, various alkanolamine absorbents, such as monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), and 2-amino-2-methyl-1-propanol (AMP), were applied to the CO2 absorption−regeneration process with different regeneration methods via thermal treatment and mineralization. Calcium chloride was added as a calcium source in the mineralization process. Integration of absorption and mineralization defined as a single process was proposed in this study to resolve the excessive requirement of energy in a conventional amine regeneration process, leading to enhanced working capacity and desorption rate without increasing the regeneration temperature. This method provides an increment of working capacity 1.3−3 times higher than the conventional thermal amine-scrubbing process. Among the tested amines, MEA exhibited the highest increase of working capacity and AMP showed the highest yield of CaCO3. MEA, DEA, and MDEA favored the formation of calcite, while AMP produced a mixture of calcite and vaterite.
1. INTRODUCTION CO2 emissions contribute to the escalation of the temperature of the earth, which results in the elevation of the global sea level. Warming of the ocean, loss of ice by glaciers and the ice sheet, and also reduction of liquid water storage of land are likely causing the sea level to rise in more than about 95% of the ocean area.1 CO2 gas has contributed to 78% of the total greenhouse gas emission increment from fossil fuel combustion and industrial processes for 40 years to 2010.2 Capturing CO2 emitted from large point sources is generally performed with an amine-scrubbing process. The amine-scrubbing process for absorption/stripping of H2S and CO2 from natural gas was patented in 1930 by Bottoms.3 This process is based on the thermal-swing regeneration of the amine reversible reaction. Although using this method to capture CO2 from flue gas means working in a lower partial pressure of CO2 and excess oxygen, this technique is attractive at the time because of its maturity. However, only a few amine-scrubbing plants for carbon capture and storage (CCS) for post-combustion have ever been built. Investing in CCS to reduce CO2 emission of the facilities means extensive operating cost and capital cost and requires considerable energy. Dealing with a low concentration of CO2 to be absorbed in the flue gas requires effective solvent and a high energy amount for regeneration.4 Therefore, improvements are required in both the carbon capture process and the solvent to increase its effectiveness. In recent years, the effectiveness of various amines has already been reviewed and concluded in advance ability of alkanolamines in CO2 absorption.5,6 Alkanolamines can be classified into primary amines, secondary amines, and tertiary amines depending upon the number of hydrogen atoms in the ammonia group replaced by other functional groups. In primary amines, one hydrogen atom has been replaced by one alkyl © XXXX American Chemical Society
group. In secondary amines, two hydrogen atoms have been replaced by two alkyl groups. In tertiary amines, all hydrogen atoms have been replaced by alkyl groups. In sterically hindered amines, the primary or secondary amine contains a bulky alkyl functional group, such as a tertiary carbon molecule.7,8 In alkanolamines, one of the alkyl groups is a hydroxyl group; hence, their basicity is slightly higher than that of other methylamines.9,10 The abilities to absorb CO2 and to regenerate are important considerations in the selection of solvents for carbon capture processes. The use of amine-based absorption and desorption stripping processes has been limited by the energy requirement of the amine regeneration. A patented process improvement uses lean vapor compression to reduce the reboiler duty by up to 12%.11 Energy is also required to store CO2 after the stripping process. The storage and transport of CO2 must meet the requirements of safety, low impact to the environment, verifiable storage, and also indefinite susceptibility.12 The available storage methods can be divided into geological storage, ocean storage, and mineralization.13 In the geological storage method, CO2 is injected directly into a geological layer of the earth, where it is converted into mineral carbonates through natural processes over 50−5600 years depending upon the concentration and condition of injected CO2.14 In ocean storage, CO2 is injected into the ocean at a great depth, where it dissolves and is deposited at the bottom of the sea in the form of hydrates.4 The mineralization method is suitable for the conversion of CO2 into carbonates on site at CCS plants. The present study focused on the integration of calcium carbonate mineralization Received: September 22, 2016 Revised: December 13, 2016 Published: December 13, 2016 A
DOI: 10.1021/acs.energyfuels.6b02448 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels
Figure 1. Schematic diagram of the experimental setup. vessel. A mass flow controller (MFC) was installed to maintain the gas flow rate into the vessel. The acidity of the liquid was measured with a pH probe. The temperatures of the liquid, the gas inside the reactor, the input gas, and the output gas were monitored using a thermocouple. Calcium carbonate was harvested from the reactor and separated from the liquid by decantation, followed by drying in an oven incubator at 80 °C for 24 h. 2.2. Performances of Amines in the Mineralization of Calcium Carbonate. Saturated CO2 solutions were prepared through amine absorption. A preheated gas mixture comprising of 30% CO2 and 70% N2 was introduced into a 1.6 M solution of each amine in the temperature of 40 °C. Anhydrous granular calcium chloride (93% purity, Sigma-Aldrich) was used as the source of calcium ions in the aqueous solution and was injected into the vessel with a syringe once absorption had reached a steady state. Ethanolamine (99%, technical grade, Acros Chemical), diethanolamine (99%, technical grade, Katayama Chemical), methyldiethanolamine (99%, technical grade, Fluka), and 2-amino-2-methyl-1-propanol (90%, technical grade, Sigma-Aldrich) solutions were used to remove CO2 from the gas mixture until the gas chromatograph indicated that the CO2 content in the output gas stream was constant. CO2 analysis was performed with gas chromatography using a Carboxen-packed column and a thermal conductivity detector (TCD) to determine the gas output concentration. The amine loading is defined as the number of moles of CO2 captured per mole of amine. The rich amine loading is the maximum CO2 concentration in the amine solution after absorption, and the lean amine loading is the minimum concentration of CO2 in the amine after desorption. The working capacity and CO2 desorption efficiency are calculated as follows:
with the absorption process in a single process to substitute regeneration of CO2 via thermal treatment in conventional amine-scrubbing technology. Up to now, amines are used to enhance CO2 absorption by an aqueous phase to produce carbonate or bicarbonate ions.15−18 Saturated amine liquids can be used as carbonate sources, and calcium chloride can be used in such systems to control precipitation. In our study, the performances of various alkanolamines in CaCO3 production with a novel single-process CCS method were investigated. Effectiveness of the process is evaluated to find out the best method to remove CO2 from amine. Furthermore, the mechanisms of the reaction in various alkanolamines are also studied according to the literature.
2. EXPERIMENTAL SECTION 2.1. Regeneration Procedure. Figure 1 shows the experimental setup for the mineralization of the CO2-saturated amine solutions. A glass reactor with a stainless-steel cover and a water-circulating bath was used. The volume of the reactor was 0.5 dm3; the H/D ratio of the vessel was equal to 2; and the L/D ratio was equal to 1. A magnetic stirrer was used to mix the liquid contents. A sparger with a pore diameter of 20 μm was used to distribute the gas inside the vessel. The reactor was equipped with an automatic back-pressure regulator to maintain a constant pressure inside the vessel. The pressure in the reactor was held at 0.2 bar gauge during the absorption process. The nitrogen-purging regeneration method was carried out by purging pure N2 gas inside the reactor with a flow rate of 0.5 L/min after absorption of CO2 finished in the temperature of 40 °C. Thermal regeneration was performed by heating each amine solution at a constant temperature of 90 °C after CO2 absorption in the same reactor. The reactor was constantly purged with 0.5 L/min CO2 during the absorption process. CO2 is fluxed constantly in the thermal regeneration method to determine whether the process is reaching a steady state by a constant output gas concentration. CO 2 concentration changes were monitored using gas chromatography along the process. A condenser was installed to prevent water vapor from entering the gas chromatograph. The gas chromatograph was positioned in line with the reactor to monitor the gas output from the
working capacity (mol of CO2 /mol of amine) = rich amine loading − lean amine loading
(1)
CO2 desorption efficiency (%) =
(rich amine loading − lean amine loading) × 100% rich amine loading
(2)
2.3. Characterization of Produced CaCO3. Powdered calcium carbonate produced by the mineralization processes was examined B
DOI: 10.1021/acs.energyfuels.6b02448 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels using a X-ray diffractometer Rigaku D/Max-2500 and cold field emission scanning electron microscopy (SEM). The gas chromatograph used a Carboxen-packed column and a TCD to analyze the output gas.
calcium chloride solution with a molar ratio equal to the CO2 molar ratio was injected into the saturated AMP solution. Mineralization was found to use a total of 97.4% of aminecaptured CO2 into calcium carbonate. Calcium amount injection is based on the stoichiometric ratio in the equation for the carbonization reaction. Calcite crystals formed during the mineralization process. 3.2. Effectiveness of Mineralization in the Regeneration of Various Alkanolamines. The effectiveness of mineralization and thermal treatment in the regeneration of the various alkanolamines was tested. Monoethanolamine (MEA) is the most commonly used solvent in gas-sweetening processes for the removal of carbon dioxide and sour gases from industrial processes. Diethanolamine (DEA), monodiethanolamine (MDEA), and AMP are other alkanolamines that have received attention in recent years in attempts to improve the CO2 absorption capacity of the conventional aminescrubbing process. The efficiencies of the processes that use these amines can be assessed by calculating their working capacities. The working capacity is the difference between the rich amine loading and the lean amine loading and can also be used to determine the solvent flow rate required for achieving a certain CO2 removal value. Figures 3 and 4 show the time
3. RESULT AND DISCUSSION 3.1. Comparison of the Regeneration Method. The regeneration of amine after the amine-scrubbing process is an important aspect of the cost-effectiveness of the system. Such regenerations are typically performed by heating the saturated amine solvent in the temperature range of 90−120 °C. This process uses a high amount of energy, mostly required by the reboiler in the scrubber. Purging with nitrogen is a conventional method for the removal of gases from liquids and was also assessed in this study as a physical desorption method. Mineralization is an alternative method for the removal of CO2 from the saturated amine solvent as calcium carbonate (CaCO3). A comparison of the desorption method to the thermal treatment and mineralization methods in 2-amino-2methyl-1-propanol (AMP) over the same period of time is shown in Figure 2.
Figure 2. CO2 loading absorption and desorption time profile curve with different desorption methods: (a) N2 purging, (b) thermal treatment at 90 °C, and (c) mineralization with calcium ions.
CO2 absorption−desorption curves for a 10 wt % aqueous AMP solution were prepared using various desorption methods: (a) N2 purging, (b) thermal treatment at 90 °C, and (c) mineralization with calcium ions. In our semi-batch system, the 10 wt % aqueous AMP solution absorbed around 0.75 mol of CO2/mol of amine at 40 °C and 1.2 bar. The three methods were compared by determining the amine-loading level at the end of each process. These regeneration processes are all terminated within 120 min. Nitrogen purging was applied at the same flow rate as the CO2 gas delivery. In contrast to the other methods, purging the amine solution with nitrogen gas did not reach an equilibrium state because CO2 is physically bonded to AMP and is released at a slow desorption rate. After purging for 2 h, the final CO2 loading level was 0.45 mol of CO2/mol of amine. The thermal treatment approach has an efficiency of CO2 desorption of 68% at 90 °C, with an amine-loading level at equilibrium of 0.24 mol of CO2/mol of amine. The mineralization method results in the most dramatic change in the CO2 loading of the AMP solution, as shown in Figure 2c. In the mineralization approach, a
Figure 3. (a) CO2 loading time profile curve for regeneration with thermal treatment in 90 °C, (b) absorption rate curve, and (c) desorption rate curve.
profile curves for CO2 absorption and regeneration in the thermal treatment and mineralization processes. The absorption rate of each amine can be calculated from the slope of the mole change in the system: the steeper the slope, the faster the reaction rate. In this study, MEA exhibits the highest rate of absorption, 0.204 mmol mol−1 s−1; i.e., the slope of its absorption curve is steeper than those of the other amines (Figure 3b). DEA exhibits an absorption rate of 0.200 mmol mol−1 s−1, which is higher than those of AMP and MDEA (Table 1). MEA has a higher absorption rate than any other amine8,19 and is therefore C
DOI: 10.1021/acs.energyfuels.6b02448 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels
Mineralization optimizes the working capacity by using CO2 absorbed in amine to produce calcium carbonate. This method provides a working capacity 1.3−3 times higher than that of thermal regeneration, as shown in Table 1. In the thermal regenerations, AMP was found to exhibit the highest working capacity, followed by MDEA, DEA, and MEA; this ordering is in agreement with the results of previous studies.19,21 In the mineralizations, AMP was also found to exhibit the highest working capacity, which implies the high conversion of CO2 to the unstable carbamate form in the absorption process. 3.3. Mechanisms of the Mineralizations in the Presence of Amine. 3.3.1. Primary and Secondary Amine Mineralization Systems. MEA is a primary amine with the molecular formula of C2H7NO. In the system containing 10 wt % MEA at 40 °C and 1.2 bar pressure, absorption and desorption are reversible reactions. Although the reaction mechanism is still controversial, the formation of carbamate as an intermediate in this system was assumed in this study (Scheme 1) according to previous studies.22−24 Figure 5 show Scheme 1. Reaction Mechanism Pathway of Primary and Secondary Amine
Figure 4. (a) CO2 loading time profile curve for regeneration with mineralization, (b) absorption rate curve, and (c) desorption rate curve.
commercially attractive for industrial applications. However, the CO2 release rate of MEA during thermal regeneration at 90 °C is slow; it has the lowest slope in Figure 3c. In contrast, MDEA provides the fastest rate of CO2 desorption under the same conditions. The desorption rate can be increased by raising the temperature or converting absorbed CO2 into another material. Lowering the solution pH by the addition of other materials also acts as an amine basicity reducer, which leads to more effective desorption of CO2.20 Absorption was conducted under the same process conditions, such as the temperature, mixing rate, and concentration of amine, in the thermal regeneration test and was found to exhibit the same trend (Figure 4b). CaCl2 is injected to the system in the same 1:1 ratio of CO2 mole amount captured by each amine. MDEA exhibits the fastest mineralization rate, as shown in Figure 4c. The presence of bicarbonate ions in the MDEA system seems to result in faster precipitation of CaCO3 than in the other amine systems. The mineralization method provides better removal of CO2 than the thermal treatment method. AMP exhibits the slowest rate of CO2 release in the mineralization method, with a value of 0.352 mmol mol−1 s−1, which indicated that a higher loading of CO2 can result in a slower desorption rate.
time profiles of pH changes in a single-reactor system. Changes in the pH system indicated CO2 equilibrium specimen in the solution. The addition of CaCl2 decreases the pH of the system and induces the protonation of carbamate to produce bicarbonate and carbonate ions, which occurred at a lower pH.24 Through the reversible reaction, free amine, bicarbonate, and carbonic acid exist in the system. The free amine formation rate constant was higher than protonation/deprotonation of carbamate in the MEA system;24 therefore, calcium bicarbonate formation is favored in the system and rapidly dissociates into calcium carbonate and water. The reaction finished after there was no calcium carbonate converted, which could be recognized by a constant pH value. The faster the reaction reaches a constant value of pH, the faster the reaction happened in the system. Changes in pH per hour can be calculated as a gradient to compare the rate of reaction in each system. In the MEA system, pH change was 0.6 h−1. The MEA system produces the lowest yield of CaCO3 because there are fewer carbonate/bicarbonate ions present in this system, as indicated by the observation that the final pH is higher than in the other
Table 1. Comparison of Amine Regeneration Effectiveness method
thermal treatment
mineralization
amine
MEA
DEA
MDEA
AMP
MEA
DEA
MDEA
AMP
rich loading (mol of CO2/mol of amine) lean loading (mol of CO2/mol of amine) absorption rate (mmol mol−1 s−1) desorption rate (mmol mol−1 s−1) working capacity (mol of CO2/mol of amine)
0.66 0.44 0.204 0.0542 0.22
0.68 0.19 0.200 0.108 0.49
0.70 0.20 0.1625 0.138 0.50
0.74 0.22 0.1916 0.083 0.52
0.66 0.017 0.204 0.355 0.64
0.68 0.023 0.200 0.383 0.66
0.70 0.044 0.1625 0.526 0.65
0.74 0.0093 0.1916 0.352 0.73
D
DOI: 10.1021/acs.energyfuels.6b02448 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels
Figure 5. Time profile of pH changes in primary and secondary amine systems.
amine systems (Table 2). The mechanism of the mineralization in the secondary amine DEA system is the same as that in the
Scheme 2. Reaction Mechanism Pathway of Tertiary Amine
Table 2. pH and Mass Yield of Mineralization in Various Amine Systems amine
initial pH
final pH
mass yield (g of CaCO3/g of CaCl2)
MEA DEA MDEA AMP
8.10 8.09 8.50 8.60
6.8 6.6 6.7 5.9
0.24 0.63 0.62 0.75
desorption as a result of the high rate of this mineralization reaction (Table 1). In comparison to the other kinds of amines, MDEA as a tertiary amine showed the fastest mineralization reaction. The gradient of the pH change slope was 0.798 h−1. 3.3.3. Primary Sterically Hindered Amine Mineralization System. AMP is a sterically hindered primary amine. The mineralization mechanism is the same as that of primary and secondary amines, except that it forms unstable carbamate species and hydrolysis eventuates easily.27 The addition of calcium chloride increases the reaction rate carbamate protonation into bicarbonate ions. Unstable carbamate species were shown by a faster absorption rate compared to the tertiary amine system but a slower rate than the primary amine system. The desorption rate is 0.352 mmol mol−1 s−1 (Table 1), and the slope gradient of the pH change profile (Figure 7) is 0.528 h−1. The more abundant the presence of bicarbonate ions in the system, the more CaCO3 generated in a single reactor. The mass yield of calcium carbonate produced over the injected calcium source is calculated as the mass of calcium carbonate divided by the mass of calcium chloride. Mineralization in the DEA system produces 0.63 g of CaCO3/g of CaCl2, which is higher than in the MEA system. The mass yields of the MEA, AMP, DEA, and MDEA systems are shown in Table 2; the AMP system gives the highest yield. The mass yield increases as the pH end value decreases. The system with a greater change of pH value implies a higher CaCO3 yield, such as in AMP systems. 3.4. Various Amine Effects on Calcium Carbonate Crystal Production. The energy of a crystal is made up of two components: the surface energy and the bulk lattice energy.28 The surface energy is dominant for small solution volumes and crystals. The proportion of the two components in a crystal system significantly influences its morphology. Our X-ray diffraction (XRD) analysis results show that the calcium carbonate crystal product of single-process absorption is calcite for MEA, DEA, and MDEA and a mixture of calcite and vaterite
MEA system; it produces carbamate after capturing CO2. The reaction rate along with pH gradient change was recorded as 0.64 h−1. 3.3.2. Tertiary Amine Mineralization System. The tertiary amine MDEA acts as a catalyst for the hydration of carbon dioxide.25 Bicarbonate ions are produced in the absorption system.26 Figure 6 showed that the time profile of pH changes indicated which CO2 equilibrium species existed in the system. In the mineralization process, bicarbonate directly reacts with a calcium source to produce calcium bicarbonate (Scheme 2). As mentioned above, MDEA exhibits the highest rate of CO2
Figure 6. Time profile of pH changes in the tertiary amine system. E
DOI: 10.1021/acs.energyfuels.6b02448 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels
the results of Ma et al., who found that no aragonite crystal is produced for pH values higher than 5.5. In higher pH systems, precipitation favors more agglomeration.30 Calcium chloride in the solution acts as a surfactant that lowers the surface tension energy in the solution. As the CO2 loading concentration increases, the amount of calcium addition injected also increases, which lowers the surface tension in the system and also its free energy.
4. CONCLUSION Four types of alkanolamines represented as MEA (primary), DEA (secondary), MDEA (tertiary), and AMP (steric hindrance) were tested to the CO2 absorption−regeneration experiment to evaluate different regeneration methods via thermal treatment and mineralization. In comparison to the thermal treatment method, mineralization could remove CO2 absorbed up to 97.4% in 1.6 M amine solution. single process of absorption and mineralization enhanced the working capacity and regeneration rate of the absorbent, especially in the case of MEA. These increases of the working capacity led to a decrease in the energy requirements of the carbon capture system. Under low surface energy conditions resulting from the presence of amine in the system, a high yield was achieved, although metastable crystal morphology, such as vaterite, was formed along with calcite in the AMP system. On the other hand, the calcite form was only obtained in the MEA, DEA, and MDEA systems. Through this work, a novel method of CO2 absorption−mineralization by the addition of CaCl2 in a single process without requirement of increasing the desorption temperature has offered a good alternative to replace the conventional regeneration treatment in the CCS system. Moreover, to make the system more efficient, recycling the solution to perform continuous mineralization is now in progress of research. Therefore, chloride ions in the system can be used to dissolve insoluble calcium mineral, such as slaked lime, for a calcium source.
Figure 7. Time profile of pH changes in the primary sterically hindered amine system.
for the AMP system (Figure 8). The XRD peaks were analyzed with the Debye−Scherrer method, and it was found that the
■
AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. ORCID
Figure 8. X-ray diffractogram of PCC_X (X = MEA, DEA, MDEA, and AMP) produced in different types of amine represent (a) primary, (b) secondary, (c) tertiary, and (d) sterically hindered amines.
Soon Kwan Jeong: 0000-0001-5347-3651 Notes
The authors declare no competing financial interest.
■
largest crystal size is that produced by AMP. The crystal sizes calculated from the XRD results increase in the order PCC_MDEA (10.46 Å), PCC_MEA (11.35 Å), PCC_DEA (12.14 Å), and PCC_AMP (22 Å). The formation of pure calcite crystal in MEA, DEA, and MDEA verifies that the surface energy controls the absorption and mineralization system for an amine concentration of 1.6 M. The formation of calcite and vaterite in the AMP system indicates that there is higher saturation in this system. Carbamate hydrolysis and the presence of bicarbonate in the system induce mineralization and produce high saturation conditions. The simultaneous formation of vaterite and calcite in this crystallization system indicates that this process is kinetically driven rather than thermodynamically driven.29 The high concentration of the reactant in the AMP system forces a kinetically driven reaction; therefore, vaterite crystal forms alongside calcite. The calcite form also results from alkaline conditions of precipitation, which is in agreement with
ACKNOWLEDGMENTS This work was conducted under the framework of the Research and Development Program of the Korea Institute of Energy Research (KIER, B6-2434).
■
REFERENCES
(1) Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change; Stocker, T. F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S. K., Boschung, J., Nauels, A., Xia, Y., Bex, V., Midgley, P. M., Eds.; Cambridge University Press: New York, 2013; p 16. (2) Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change; Edenhofer, O., PichsMadruga, R., Sokona, Y., Minx, J. C., Farahani, E., Susanne, K., Seyboth, K., Adler, A., Baum, I., Brunner, S., Eickemeier, P., Kriemann,
F
DOI: 10.1021/acs.energyfuels.6b02448 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels B., Savolainen, J., Schlömer, S., von Stechow, C., Zwickel, T., Eds.; Cambridge University Press: New York, 2014. (3) Bottoms, R. R. Process for separating acidic gases. U.S. Patent 1,783,901 A, Dec 2, 1930. (4) Pires, J. C. M.; Martins, F. G.; Alvim-Ferraz, M. C. M.; Simões, M. Chem. Eng. Res. Des. 2011, 89 (9), 1446−1460. (5) Rao, A. B.; Rubin, E. S. Environ. Sci. Technol. 2002, 36 (20), 4467−4475. (6) Abu-Zahra, M. R. M.; Sodiq, A.; Feron, P. H. M. Commercial liquid absorbent-based PCC processes. In Absorption-Based Postcombustion Capture of Carbon Dioxide; Feron, P., Ed.; Elsevier, Ltd.: Amsterdam, Netherlands, 2016; Chapter 29, pp 757−778, DOI: 10.1016/B978-0-08-100514-9.00029-9. (7) Singh, P.; Wim Brilman, D. W. F.; Groeneveld, M. J. Energy Procedia 2009, 1 (1), 1257−1264. (8) Singh, P.; Versteeg, G. F. Process Saf. Environ. Prot. 2008, 86 (5), 347−359. (9) Singh, P.; Niederer, J. P. M.; Versteeg, G. F. Int. J. Greenhouse Gas Control 2007, 1, 5−10. (10) Singh, P.; Niederer, J. P. M.; Versteeg, G. F. Chem. Eng. Res. Des. 2009, 87 (2), 135−144. (11) Reddy, S.; Johnson, D.; Gilmartin, J. Proceedings of the 7th Power Plant Air Pollutant Control “Mega” Symposium; Baltimore, MD, Aug 25−28, 2008; pp 1−17. (12) Lackner, K. S.; Brennan, S. Clim. Change 2009, 96 (3), 357− 378. (13) Liu, Y.; Ye, Q.; Shen, M.; Shi, J.; Chen, J.; Pan, H.; Shi, Y. Environ. Sci. Technol. 2011, 45 (13), 5710−5716. (14) Sanna, A.; Uibu, M.; Caramanna, G.; Kuusik, R.; Maroto-Valer, M. M. Chem. Soc. Rev. 2014, 43, 8049−8080. (15) Vucak, M.; Peric, J.; Krstulovic, R. Powder Technol. 1997, 91, 69−74. (16) Gorna, K.; Hund, M.; Vučak, M.; Gröhn, F.; Wegner, G. Mater. Sci. Eng., A 2008, 477 (1−2), 217−225. (17) Vinoba, M.; Bhagiyalakshmi, M.; Grace, A. N.; Chu, D. H.; Nam, S. C.; Yoon, Y.; Yoon, S. H.; Jeong, S. K. Langmuir 2013, 29 (50), 15655−15663. (18) Vinoba, M.; Bhagiyalakshmi, M.; Choi, S. Y.; Park, K. T.; Kim, H. J.; Jeong, S. K. J. Phys. Chem. C 2014, 118, 17556−17556. (19) Adeosun, A.; El Hadri, N.; Goetheer, E.; Abu-Zahra, M. R. M. Int. J. Eng. Sci. 2013, 3 (9), 12−23. (20) Puxty, G.; Maeder, M. The fundamentals of post-combustion capture. In Absorption-Based Post-combustion Capture of Carbon Dioxide; Feron, P., Ed.; Elsevier, Ltd.: Amsterdam, Netherlands, 2016; Chapter 2, pp 13−33, DOI: 10.1016/B978-0-08-1005149.00002-0. (21) Singh, P. Amine Based Solvent for CO2 Absorption “From Molecular Structure to Process”. Thesis, University of Twente, Enschede, Netherlands, 2011. (22) Couchaux, G.; Barth, D.; Jacquin, M.; Faraj, A.; Grandjean, J. Oil Gas Sci. Technol. 2014, 69 (5), 865−884. (23) Littel, R. J.; Versteeg, G. F.; Van Swaaij, W. P. M. Chem. Eng. Sci. 1992, 47 (8), 2027−2035. (24) McCann, N.; Phan, D.; Wang, X.; Conway, W.; Burns, R.; Attalla, M.; Puxty, G.; Maeder, M. J. Phys. Chem. A 2009, 113 (17), 5022−5029. (25) Donaldson, T. L.; Nguyen, Y. N. Ind. Eng. Chem. Fundam. 1980, 19 (3), 260−266. (26) Zhang, X.; Zhang, C.; Liu, Y. Ind. Eng. Chem. Res. 2002, 41, 1135−1141. (27) Kim, Y. E.; Lim, J. A.; Jeong, S. K.; Yoon, Y. I.; Bae, S. T.; Nam, S. C. Bull. Korean Chem. Soc. 2013, 34 (3), 783−787. (28) Gibbs, J. W. The Collected Works of J. Willard Gibbs; Longmans, Green and Co.: New York, 1961; Vol. 1. (29) de Leeuw, N. H.; Parker, S. C. J. Phys. Chem. B 1998, 102 (16), 2914−2922. (30) Ma, Y. F.; Gao, Y. H.; Feng, Q. L. J. Cryst. Growth 2010, 312 (21), 3165−3170.
G
DOI: 10.1021/acs.energyfuels.6b02448 Energy Fuels XXXX, XXX, XXX−XXX
