Species distribution of CO 2 absorption/desorption in aqueous and non-aqueous N -ethylmonoethanolamine solutions

Chen, Siming; Chen, Shaoyun; Zhang, Yongchun; Qin, Liang; Guo, Chao; Chen, Jian

doi:10.1016/j.ijggc.2016.01.046

Cited by 45 publications

(38 citation statements)

References 43 publications

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“…During the desorption process in aqueous absorbents, the concentration of carbamates increased until the maximum was reached and then decreased; this was consistent with the trend that the signal peak intensities of some carbamates first increased and then decreased. This phenomenon could be explained by R 1 R 2 NH 2 + (R 1 R 2 NH 2 + represents TETAH + or AMPH + ) reacting with bicarbonate to form carbamates and only part of bicarbonate being released as CO 2 with the residual bicarbonate transferred to carbamate that cannot be regenerated . Meanwhile, R 1 R 2 NH 2 + reacted with carbamate to release CO 2 .…”

Section: Resultsmentioning

confidence: 99%

Performance and Mechanisms of Triethylene Tetramine (TETA) and 2-Amino-2-methyl-1-propanol (AMP) in Aqueous and Nonaqueous Solutions for CO₂ Capture

Liu

Jing

Zhou

et al. 2017

ACS Sustainable Chem. Eng.

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Nonaqueous amines are currently being explored for energy-efficient postcombustion CO2 capture, but the absorption capacity and regeneration efficiency of most absorbents still need to be further improved. In this work, a mixture of triethylene tetramine (TETA) and 2-amino-2-methyl-1-propanol (AMP) dissolved in ethanol was chosen as a nonaqueous absorbent for CO2 capture and performed with high absorption loading and regeneration efficiency. In addition, the changes of the components during the absorption–desorption process and reaction mechanisms of nonaqueous absorbents were explored by 13C NMR spectroscopy and compared with those of aqueous absorbents. The results showed that TETA/AMP/ethanol had higher absorption loading and regeneration efficiency (3.71 mol kg–1, 95.4%) after the fifth regeneration cycle than TETA/AMP/water (3.54 mol kg–1, 38.8%) when the amine mass concentration was 40 wt %. CO2 capture by TETA/AMP aqueous and nonaqueous solutions proceeded by two different mechanisms. Polycarbamate and alkyl carbonate of C2H5OCO2 – formed in the TETA/AMP/ethanol solution, while polycarbamates and HCO3 –/CO3 2– formed in the TETA/AMP/water solution. Moreover, the regeneration efficiency of the nonaqueous solution was higher than that of the aqueous solution because the reaction products were easily decomposed in ethanol, and the regeneration consumption of the organic solvent was lower than that of water.

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Section: Resultsmentioning

confidence: 99%

Performance and Mechanisms of Triethylene Tetramine (TETA) and 2-Amino-2-methyl-1-propanol (AMP) in Aqueous and Nonaqueous Solutions for CO₂ Capture

Liu

Jing

Zhou

et al. 2017

ACS Sustainable Chem. Eng.

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“…In order to understand their different absorption behaviors by the replacement of water with the organic solvent EGBE, 13 C NMR and FTIR characterizations were performed to verify the product species in nonaqueous and aqueous amine solvents during CO 2 absorption. Peak assignment was performed according to literature data. ,,,,,− In our previous work, it was pointed out that misleading carbon signals could be found for the nonaqueous samples using D 2 O as an NMR solvent. DMSO- d 6 was used as a solvent instead of D 2 O for all the nonaqueous samples in order to prevent the carbamate hydrolysis.…”

Section: Resultsmentioning

confidence: 99%

“…Using organic solvents to replace water in the absorbents has proved to have significant advantages as for saving regeneration energy and potentially reducing corrosiveness and degradation. As a result, nonaqueous absorbents by blending secondary amines with organics have led to the advance development. ,− These reported organic solvents include volatile alcohols (e.g., methanol, ethanol, and butanol), low-volatile alcohols and glycols (e.g., benzyl alcohol and ethylene glycol) or their mixtures, glymes, dimethyl formamide (DMF), and ionic liquids. However, high-volatile alcohols (e.g., methanol and ethanol) as cosolvents can produce huge solvent loss when treating large-scale flue gas volume; thus, it seems to be impractical for potential industrial use.…”

Section: Introductionmentioning

confidence: 99%

Energy-Efficient CO₂ Capture Using Nonaqueous Absorbents of Secondary Alkanolamines with a 2-Butoxyethanol Cosolvent

Ping

Dong

Shen

2020

ACS Sustainable Chem. Eng.

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Nonaqueous amine-based absorbents by replacing water with organic solvents have potential advantages of low energy penalty and reduced amine degradation for CO 2 capture. An advanced nonaqueous system of 2-(butylamino)ethanol (BAE) with 2-butoxyethanol (EGBE) was proposed for low-energy consumption CO 2 capture. EGBE was selected as a green cosolvent because of its superior properties over the reported organics and water. A comprehensive study on CO 2 capture performance has been performed for secondary alkanolamine nonaqueous systems such as 2-(methylamino)ethanol (MAE), 2-(ethylamino)ethanol (EAE), and BAE and their aqueous counterparts. Product species in CO 2 -loaded solutions were identified by 13 C nuclear magnetic resonance and Fourier transform infrared spectroscopy. Regeneration energy consumption was also evaluated using a modified method and compared with that of conventional aqueous monoethanolamine (MEA). Results demonstrated that the aqueous 5.0 M secondary amine absorbents had higher absorption capacity and larger cyclic capacity than their nonaqueous counterparts. The desorption efficiency for both systems was in a descending order: BAE > EAE > MAE. Surprisingly, the cyclic capacity of aqueous and nonaqueous BAE systems was about 180 and 100% higher than that of aqueous MEA, respectively. The underlying reasons were also discussed. CO 2 can react with these amines, forming unstable carbamates and protonated amines in the EGBE solvent, whereas it forms bicarbonate species in addition to ionic couples in aqueous solutions. The regeneration heat duty of nonaqueous EGBE-based secondary amine absorbents was about 45−55% lower than that of aqueous MEA (3.82 MJ kg −1 CO 2 ). In addition, the feasibility of low-temperature desorption makes the BAE/EGBE absorbent a compelling solution for energy-saving CO 2 capture technology using low-grade industrial waste heat.

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“…In recent years, nonaqueous solvent blends formed by amine and a conventional organic solvent have been developed as promising alternatives to the aqueous amine absorbents, because they can provide the advantage of reducing the energy cost during the regeneration steps while retaining high CO 2 capacity [5]. At present, many nonaqueous systems were studied to capture CO 2 , such as the mixture of alcohol and amidines [6], alkanolamine solutions such as monoethanolamine (MEA) and 2-amino-2-methyl-1-propanol (AMP) in ethanol or ethylene glycol (EG) [7][8][9][10][11][12][13][14], and the amine-based deep eutectic solvents [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

CO2 Absorption Mechanism by the Nonaqueous Solvent Consisting of Hindered Amine 2-[(1,1-dimethylethyl)amino]ethanol and Ethylene Glycol

Yang

2020

Molecules

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In this work, we studied the CO2 absorption mechanism by nonaqueous solvent comprising hindered amine 2-[(1,1-dimethylethyl)amino]ethanol (TBAE) and ethylene glycol (EG). The NMR and FTIR results indicated that CO2 reacted with an -OH group of EG rather than the -OH of TBAE by producing hydroxyethyl carbonate species. A possible reaction pathway was suggested, which involves two steps. In the first step, the acid–base reaction between TBAE and EG generated the anion HO-CH2-CH2-O-; in the second step, the O− of HO-CH2-CH2-O− attacked the C atom of CO2, forming carbonate species.

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Species distribution of CO 2 absorption/desorption in aqueous and non-aqueous N -ethylmonoethanolamine solutions

Cited by 45 publications

References 43 publications

Performance and Mechanisms of Triethylene Tetramine (TETA) and 2-Amino-2-methyl-1-propanol (AMP) in Aqueous and Nonaqueous Solutions for CO₂ Capture

Performance and Mechanisms of Triethylene Tetramine (TETA) and 2-Amino-2-methyl-1-propanol (AMP) in Aqueous and Nonaqueous Solutions for CO₂ Capture

Energy-Efficient CO₂ Capture Using Nonaqueous Absorbents of Secondary Alkanolamines with a 2-Butoxyethanol Cosolvent

CO2 Absorption Mechanism by the Nonaqueous Solvent Consisting of Hindered Amine 2-[(1,1-dimethylethyl)amino]ethanol and Ethylene Glycol

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Species distribution of CO 2 absorption/desorption in aqueous and non-aqueous N -ethylmonoethanolamine solutions

Cited by 45 publications

References 43 publications

Performance and Mechanisms of Triethylene Tetramine (TETA) and 2-Amino-2-methyl-1-propanol (AMP) in Aqueous and Nonaqueous Solutions for CO2 Capture

Performance and Mechanisms of Triethylene Tetramine (TETA) and 2-Amino-2-methyl-1-propanol (AMP) in Aqueous and Nonaqueous Solutions for CO2 Capture

Energy-Efficient CO2 Capture Using Nonaqueous Absorbents of Secondary Alkanolamines with a 2-Butoxyethanol Cosolvent

CO2 Absorption Mechanism by the Nonaqueous Solvent Consisting of Hindered Amine 2-[(1,1-dimethylethyl)amino]ethanol and Ethylene Glycol

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Product

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Performance and Mechanisms of Triethylene Tetramine (TETA) and 2-Amino-2-methyl-1-propanol (AMP) in Aqueous and Nonaqueous Solutions for CO₂ Capture

Performance and Mechanisms of Triethylene Tetramine (TETA) and 2-Amino-2-methyl-1-propanol (AMP) in Aqueous and Nonaqueous Solutions for CO₂ Capture

Energy-Efficient CO₂ Capture Using Nonaqueous Absorbents of Secondary Alkanolamines with a 2-Butoxyethanol Cosolvent