The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Graeme Puxty - One of the best experts on this subject based on the ideXlab platform.
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Role of mono- and diamines as kinetic promoters in mixed aqueous amine solution for CO2 capture
Chemical Engineering Science, 2021Co-Authors: Min Xiao, William Conway, Graeme Puxty, Ding Cui, Qi Yang, Zhiwu Liang, Paul FeronAbstract:Abstract Tertiary amines are thermodynamically efficient CO2 absorbents but unfortunately suffer from low absorption rates. To overcome this issue the use of formulated absorbents incorporating simple aliphatic amines and Di-Amines as promoters have been suggested. This work describes the fundamental CO2 capture behaviour in tertiary amine diethylethanolamine (DEEA) based solution with a series of kinetic promoters monoethanolamine (MEA), N,N-dimethyl-1,3-propanediamine (N,N-DM13PDA), N,N-dimethyl-1,2-ethanediamine (N,N-DM12EDA), and 4-amino-1-methylpiperidine (4-A1MPD). The CO2 absorption rate and cyclic capacity was significantly enhanced due to the additional diamines. Using NMR technology, the underlying effect of the additives on the chemical speciation e.g. carbamate, (bi)carbonate was interrogated. The absorbents were found to initially favour carbamate at low CO2 loadings, transitioning to the energetically favoured (bi)carbonate adduct as the total CO2 concentration elevates. Unlike the energy intensive MEA absorbent, rapid and deep CO2 removal was achieved in the new proposed di-amine blend solutions, affirming its promising potential for CO2 capture.
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Advanced designer amines for CO2 capture: Interrogating speciation and physical properties
International Journal of Greenhouse Gas Control, 2019Co-Authors: Min Xiao, William Conway, Graeme Puxty, Ding Cui, Qi Yang, Zhiwu Liang, Paul FeronAbstract:Abstract Large scale and affordable CO2 capture is currently limited by absorbents with somewhat non-optimised chemical and physical properties. Cyclic designer amines with multiple amine groups and tunable molecular structure are proposed to contribute favorably to improve absorbent performance and robustness for CO2 capture. In this work the impact of cyclic structure on absorbent performance has been investigated using 4-amino-1-methylpiperidine (4-A1MPD) as a model designer amine and is compared with its linear di-amine analogue N,N-dimethyl-1,3-propanediamine (N,N-DM13PDA). The benchmark absorbent monoethanolamine (MEA) was investigated in parallel. To illustrate the significance of the cyclic structural feature, adoption of other structural changes such as methyl and propyl groups, and C2 to C3 backbone chain lengths were also investigated for comparison using the cyclic di-amine 4-amino-1-propylpiperidine (4-A1PPD) and linear di-amine N,N-dimethyl-1,2-ethanediamine (N,N-DM12EDA). CO2 absorption and desorption experiments were performed at 40 and 90 °C with analysis of the solutions to determine the speciation including carbamate(s), and carbonates, performed using 13C/1H NMR spectroscopy. The results in terms of the observed CO2 absorption rate, equilibrium CO2 solubility, CO2 desorption rate and cyclic capacity affirm that the cyclic structure strongly influences the general performance of the absorbents evaluated here. The mild steric hindrance induced by the proximity of the primary amine group to the ring acts to destabilize the carbamate and promote formation of bicarbonate resulting in 70% and 78% more bicarbonate in 4-A1MPD and 4-A1PPD than that in MEA while the values for N,N-DM12EDA and N,N-DM13PDA are 47% and 31%. Furthermore, the cyclic capacity was promoted to 215%, 160%, 81% and 65% for 4-A1PPD, 4-A1MPD, N,N-DM13PDA and N,N-DM12EDA in comparison with MEA solution. Density and viscosity of 2 mol·L−1 Di-Amines and 4 mol·L−1 MEA solutions were investigated over the temperature range 20–80 °C and found to decrease with increasing temperature for all absorbents. The order of the densities can be ranked as: MEA > 4-A1MPD > 4-A1PPD > N,N-DM12EDA > N,N-DM13PDA while the viscosities follow the trend 4-A1PPD > 4-A1MPD > N,N-DM13PDA > N,N-DM12EDA > MEA.
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Protonation constants and thermodynamic properties of amines for post combustion capture of CO2
The Journal of Chemical Thermodynamics, 2012Co-Authors: Debra Fernandes, Robert C. Burns, Geoffrey A. Lawrance, William Conway, Marcel Maeder, Xiaoguang Wang, Graeme PuxtyAbstract:Abstract The leading process for the post combustion capture (PCC) of CO2 from coal-fired power stations and hence reduction in greenhouse gases involves capture by aqueous amine solutions. Of the reactions that occur in solution, which include CO2 hydration, de-protonation of carbonic acid, amine protonation and carbamate formation, the protonation of the amine in the absorber and its subsequent de-protonation in the stripper involve the greatest enthalpy changes. In this study, protonation constants (reported as log10 Kprot) of selected series of primary, secondary and tertiary alkanolamines/amines over the temperature range 288–318 K are reported. Selected series studied involve primary, secondary and tertiary mono-, di- and tri-alkanolamines, secondary amines including heterocyclic species, and both –CH2OH and –CH2CH2OH substituted piperidines. van’t Hoff analyses have resulted in the standard molar enthalpies, ΔHmo, and molar entropies, ΔSmo, of protonation. Trends in ΔHmo are correlated with systematic changes in composition and structure of the selected series of amines/alkanolamines, while ΔHmo–ΔSmo plots generated linear correlations for the mono-, di-, and tri-alkanolamines, the –CH2OH and –CH2CH2OH substituted piperidines, and the alkylamines. These relationships provide a guide to the selection of an amine(s) solvent for CO2 capture, based on a greater difference in log10 Kprot between the absorber and stripper temperatures.
Paul Feron - One of the best experts on this subject based on the ideXlab platform.
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Role of mono- and diamines as kinetic promoters in mixed aqueous amine solution for CO2 capture
Chemical Engineering Science, 2021Co-Authors: Min Xiao, William Conway, Graeme Puxty, Ding Cui, Qi Yang, Zhiwu Liang, Paul FeronAbstract:Abstract Tertiary amines are thermodynamically efficient CO2 absorbents but unfortunately suffer from low absorption rates. To overcome this issue the use of formulated absorbents incorporating simple aliphatic amines and Di-Amines as promoters have been suggested. This work describes the fundamental CO2 capture behaviour in tertiary amine diethylethanolamine (DEEA) based solution with a series of kinetic promoters monoethanolamine (MEA), N,N-dimethyl-1,3-propanediamine (N,N-DM13PDA), N,N-dimethyl-1,2-ethanediamine (N,N-DM12EDA), and 4-amino-1-methylpiperidine (4-A1MPD). The CO2 absorption rate and cyclic capacity was significantly enhanced due to the additional diamines. Using NMR technology, the underlying effect of the additives on the chemical speciation e.g. carbamate, (bi)carbonate was interrogated. The absorbents were found to initially favour carbamate at low CO2 loadings, transitioning to the energetically favoured (bi)carbonate adduct as the total CO2 concentration elevates. Unlike the energy intensive MEA absorbent, rapid and deep CO2 removal was achieved in the new proposed di-amine blend solutions, affirming its promising potential for CO2 capture.
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Advanced designer amines for CO2 capture: Interrogating speciation and physical properties
International Journal of Greenhouse Gas Control, 2019Co-Authors: Min Xiao, William Conway, Graeme Puxty, Ding Cui, Qi Yang, Zhiwu Liang, Paul FeronAbstract:Abstract Large scale and affordable CO2 capture is currently limited by absorbents with somewhat non-optimised chemical and physical properties. Cyclic designer amines with multiple amine groups and tunable molecular structure are proposed to contribute favorably to improve absorbent performance and robustness for CO2 capture. In this work the impact of cyclic structure on absorbent performance has been investigated using 4-amino-1-methylpiperidine (4-A1MPD) as a model designer amine and is compared with its linear di-amine analogue N,N-dimethyl-1,3-propanediamine (N,N-DM13PDA). The benchmark absorbent monoethanolamine (MEA) was investigated in parallel. To illustrate the significance of the cyclic structural feature, adoption of other structural changes such as methyl and propyl groups, and C2 to C3 backbone chain lengths were also investigated for comparison using the cyclic di-amine 4-amino-1-propylpiperidine (4-A1PPD) and linear di-amine N,N-dimethyl-1,2-ethanediamine (N,N-DM12EDA). CO2 absorption and desorption experiments were performed at 40 and 90 °C with analysis of the solutions to determine the speciation including carbamate(s), and carbonates, performed using 13C/1H NMR spectroscopy. The results in terms of the observed CO2 absorption rate, equilibrium CO2 solubility, CO2 desorption rate and cyclic capacity affirm that the cyclic structure strongly influences the general performance of the absorbents evaluated here. The mild steric hindrance induced by the proximity of the primary amine group to the ring acts to destabilize the carbamate and promote formation of bicarbonate resulting in 70% and 78% more bicarbonate in 4-A1MPD and 4-A1PPD than that in MEA while the values for N,N-DM12EDA and N,N-DM13PDA are 47% and 31%. Furthermore, the cyclic capacity was promoted to 215%, 160%, 81% and 65% for 4-A1PPD, 4-A1MPD, N,N-DM13PDA and N,N-DM12EDA in comparison with MEA solution. Density and viscosity of 2 mol·L−1 Di-Amines and 4 mol·L−1 MEA solutions were investigated over the temperature range 20–80 °C and found to decrease with increasing temperature for all absorbents. The order of the densities can be ranked as: MEA > 4-A1MPD > 4-A1PPD > N,N-DM12EDA > N,N-DM13PDA while the viscosities follow the trend 4-A1PPD > 4-A1MPD > N,N-DM13PDA > N,N-DM12EDA > MEA.
Diane Thomas - One of the best experts on this subject based on the ideXlab platform.
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Postcombustion CO2 Capture by Chemical Absorption: Screening of Aqueous Amine(s)-based solvents
Energy Procedia, 2013Co-Authors: Lionel Dubois, Diane ThomasAbstract:Abstract The purpose of our work was to evaluate separately the absorption and regeneration performances of different types of amine(s) based solvents (primary, secondary and tertiary alkanolamines, sterically hindered amines, non-cyclical tetramine and cyclical absorption activators) by carrying out screening tests using small scale apparatus: a gas-liquid contactor for absorption, namely a double-stirred cell, and a regeneration cell. Absorption and regeneration performances of the solvents were compared thanks to calculated absorption and regeneration efficiencies. Concerning the absorption results, the positive effect of an activator, and especially the cyclical di-amine piperazine (PZ), on the absorption performances of the different simple amine solutions was clearly highlighted. The activation of the secondary amine MMEA by PZ gives also higher absorption efficiencies. Regarding the regeneration tests, the better regeneration performances of tertiary and sterically hindered amines (MDEA and AMP) were confirmed. For the amines blends, higher regeneration performances were observed with PZ activated solutions than with PIP activated solutions. These absorption and regeneration results will be taken into account in the solvent selection for future combined absorption-regeneration tests.
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Study of the Postcombustion CO2 Capture by Absorption into Amine(s) Based Solvents: Application to Cement Flue Gases☆
Energy Procedia, 2013Co-Authors: Lionel Dubois, Diane ThomasAbstract:Abstract The purpose of this work was to evaluate the absorption-regeneration performances of different types of amine(s) based solvents (primary, secondary and tertiary alkanolamines, sterically hindered amines, non-cyclical tetramine and cyclical absorption activators), previously selected thanks to a methodological study and separate laboratory absorption and regeneration tests. In this work absorption-regeneration experiments were carried out using a newly developed CO2 capture laboratory micro-pilot and applying a high gaseous CO2 content (from 20% to 30%) representative of cement plant flue gases. The different experiments allowed us to compare a large number of solvents (simples and blends) by weighing absorption and regeneration performances measured in our plant. The positive effect of an activator (especially the cyclical di-amine piperazine, from 5 to 10%) on the absorption-regeneration performances of the different solutions (especially on the sterically hindered amine 2-amino-2-methyl-1-propanol and on the secondary amines diethanolamine and methylmonoethanolamine, 30% solutions) was clearly highlighted. The influence of other components present in industrial emissions, especially in cement plant flue gases (mainly O2, SOx, and NOx), on the absorption-regeneration performances of the amine solvents was also studied.
William Conway - One of the best experts on this subject based on the ideXlab platform.
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Role of mono- and diamines as kinetic promoters in mixed aqueous amine solution for CO2 capture
Chemical Engineering Science, 2021Co-Authors: Min Xiao, William Conway, Graeme Puxty, Ding Cui, Qi Yang, Zhiwu Liang, Paul FeronAbstract:Abstract Tertiary amines are thermodynamically efficient CO2 absorbents but unfortunately suffer from low absorption rates. To overcome this issue the use of formulated absorbents incorporating simple aliphatic amines and Di-Amines as promoters have been suggested. This work describes the fundamental CO2 capture behaviour in tertiary amine diethylethanolamine (DEEA) based solution with a series of kinetic promoters monoethanolamine (MEA), N,N-dimethyl-1,3-propanediamine (N,N-DM13PDA), N,N-dimethyl-1,2-ethanediamine (N,N-DM12EDA), and 4-amino-1-methylpiperidine (4-A1MPD). The CO2 absorption rate and cyclic capacity was significantly enhanced due to the additional diamines. Using NMR technology, the underlying effect of the additives on the chemical speciation e.g. carbamate, (bi)carbonate was interrogated. The absorbents were found to initially favour carbamate at low CO2 loadings, transitioning to the energetically favoured (bi)carbonate adduct as the total CO2 concentration elevates. Unlike the energy intensive MEA absorbent, rapid and deep CO2 removal was achieved in the new proposed di-amine blend solutions, affirming its promising potential for CO2 capture.
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Advanced designer amines for CO2 capture: Interrogating speciation and physical properties
International Journal of Greenhouse Gas Control, 2019Co-Authors: Min Xiao, William Conway, Graeme Puxty, Ding Cui, Qi Yang, Zhiwu Liang, Paul FeronAbstract:Abstract Large scale and affordable CO2 capture is currently limited by absorbents with somewhat non-optimised chemical and physical properties. Cyclic designer amines with multiple amine groups and tunable molecular structure are proposed to contribute favorably to improve absorbent performance and robustness for CO2 capture. In this work the impact of cyclic structure on absorbent performance has been investigated using 4-amino-1-methylpiperidine (4-A1MPD) as a model designer amine and is compared with its linear di-amine analogue N,N-dimethyl-1,3-propanediamine (N,N-DM13PDA). The benchmark absorbent monoethanolamine (MEA) was investigated in parallel. To illustrate the significance of the cyclic structural feature, adoption of other structural changes such as methyl and propyl groups, and C2 to C3 backbone chain lengths were also investigated for comparison using the cyclic di-amine 4-amino-1-propylpiperidine (4-A1PPD) and linear di-amine N,N-dimethyl-1,2-ethanediamine (N,N-DM12EDA). CO2 absorption and desorption experiments were performed at 40 and 90 °C with analysis of the solutions to determine the speciation including carbamate(s), and carbonates, performed using 13C/1H NMR spectroscopy. The results in terms of the observed CO2 absorption rate, equilibrium CO2 solubility, CO2 desorption rate and cyclic capacity affirm that the cyclic structure strongly influences the general performance of the absorbents evaluated here. The mild steric hindrance induced by the proximity of the primary amine group to the ring acts to destabilize the carbamate and promote formation of bicarbonate resulting in 70% and 78% more bicarbonate in 4-A1MPD and 4-A1PPD than that in MEA while the values for N,N-DM12EDA and N,N-DM13PDA are 47% and 31%. Furthermore, the cyclic capacity was promoted to 215%, 160%, 81% and 65% for 4-A1PPD, 4-A1MPD, N,N-DM13PDA and N,N-DM12EDA in comparison with MEA solution. Density and viscosity of 2 mol·L−1 Di-Amines and 4 mol·L−1 MEA solutions were investigated over the temperature range 20–80 °C and found to decrease with increasing temperature for all absorbents. The order of the densities can be ranked as: MEA > 4-A1MPD > 4-A1PPD > N,N-DM12EDA > N,N-DM13PDA while the viscosities follow the trend 4-A1PPD > 4-A1MPD > N,N-DM13PDA > N,N-DM12EDA > MEA.
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Protonation constants and thermodynamic properties of amines for post combustion capture of CO2
The Journal of Chemical Thermodynamics, 2012Co-Authors: Debra Fernandes, Robert C. Burns, Geoffrey A. Lawrance, William Conway, Marcel Maeder, Xiaoguang Wang, Graeme PuxtyAbstract:Abstract The leading process for the post combustion capture (PCC) of CO2 from coal-fired power stations and hence reduction in greenhouse gases involves capture by aqueous amine solutions. Of the reactions that occur in solution, which include CO2 hydration, de-protonation of carbonic acid, amine protonation and carbamate formation, the protonation of the amine in the absorber and its subsequent de-protonation in the stripper involve the greatest enthalpy changes. In this study, protonation constants (reported as log10 Kprot) of selected series of primary, secondary and tertiary alkanolamines/amines over the temperature range 288–318 K are reported. Selected series studied involve primary, secondary and tertiary mono-, di- and tri-alkanolamines, secondary amines including heterocyclic species, and both –CH2OH and –CH2CH2OH substituted piperidines. van’t Hoff analyses have resulted in the standard molar enthalpies, ΔHmo, and molar entropies, ΔSmo, of protonation. Trends in ΔHmo are correlated with systematic changes in composition and structure of the selected series of amines/alkanolamines, while ΔHmo–ΔSmo plots generated linear correlations for the mono-, di-, and tri-alkanolamines, the –CH2OH and –CH2CH2OH substituted piperidines, and the alkylamines. These relationships provide a guide to the selection of an amine(s) solvent for CO2 capture, based on a greater difference in log10 Kprot between the absorber and stripper temperatures.
Zareen Akhter - One of the best experts on this subject based on the ideXlab platform.
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Synthesis, characterization and thermal oxidative stability of rigid epoxy polymers cured from aromatic mono- and Di-Amines
Journal of Polymer Research, 2013Co-Authors: Humaira Masood Siddiqi, Adeel Afzal, Samia Sajid, Zareen AkhterAbstract:Synthesis, characterization and thermal properties of some rigid epoxy polymers cured from aromatic mono- and di-amine are presented. The aromatic mono- and di-amine are prepared via nucleophilic substitution reaction of p -nitrochlorobenzene with the respective mono- and di-hydroxybiphenyl, and via subsequent hydrogenation of the aromatic nitro products. The structures of both, mono- and Di-Amines, are confirmed by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (^1HNMR) and elemental (CHN) analysis. Furthermore, three types of rigid epoxy polymers, (i) HBREP, (ii) HCREP, and (iii) BCREP, are prepared by melt processing and curing of the epoxy monomers with (i) monoamine, (ii) diamine, and (iii) 1: 1 mixture of mono- and Di-Amines, respectively. These rigid epoxy polymers are characterized by FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). TGA and DSC results show excellent thermal oxidative stability (T_d10 ≥ 400 °C) and substantially high glass transition temperatures (T_g = 80–120 °C) for these rigid epoxy polymers. The intermediary BCREP exhibits the highest T_g as well as the maximum heat resistance and thermal stability regardless of its lower chemical crosslink density with respect to HCREP. The kinetic analyses of the oxidative degradation of polymers also reveal sufficiently high activation energy of pyrolysis for BCREP.