The Experts below are selected from a list of 3426 Experts worldwide ranked by ideXlab platform
Hallvard F. Svendsen - One of the best experts on this subject based on the ideXlab platform.
-
Modeling temperature dependent and absolute Carbamate stability constants of amines for CO2 capture
International Journal of Greenhouse Gas Control, 2020Co-Authors: Mayuri Gupta, Hallvard F. SvendsenAbstract:Abstract Thermodynamic properties and Carbamate stability constants (Kc) for a dataset of 25 amines and alkanolamines, with desirable post combustion CO2 capture (PCC) solvent properties, have been studied extensively employing various gaseous phase calculations and solvation models. A comprehensive study of gaseous phase free energy and enthalpy is carried out using density functional methods [B3LYP/6-311++G(d,p)], and composite methods (G3MP2B3, G3MP2, G4MP2 and CBS-QB3). Implicit solvation models (PCM, SM8T and DivCon) and the Explicit Solvation Shell Model (ESS) were used to study solvation free energy of various neutral and ionic species present in the amine-Carbamate Formation reaction. Temperature dependent Carbamate stability constants are calculated for the Carbamate Formation reaction of amines and alkanolamines to better understand the effect of temperature on temperature swing absorption-desorption PCC processes. The temperature dependency of Kc was compared against available experimental data.
-
Understanding Carbamate Formation Reaction Thermochemistry of Amino Acids as Solvents for Postcombustion CO2 Capture.
The Journal of Physical Chemistry B, 2019Co-Authors: Mayuri Gupta, Hallvard F. SvendsenAbstract:The Carbamate stability constant for a data set of 10 amino acids, having potential for being postcombustion CO2 capture (PCC) solvents, has been calculated using various implicit and explicit solvation shell models. This work also includes an extensive study of gas-phase free energy and enthalpy for the amino acid Carbamate Formation reaction with the Hartree Fock method, density functional methods [B3LYP/6-311++G(d,p)], and composite methods (G3MP2B3, G3MP2, CBS-QB3, and G4MP2). Ideal PCC solvent properties require finding a profitable tradeoff between various thermodynamic and system optimization parameters. Benchmark gaseous-phase and solution-phase thermodynamic properties given in this work can help in making informed decisions when choosing promising PCC solvents. The temperature dependency of the Carbamate stability constant of amino acids is predicted using PCM and SM8T implicit solvation models. PCC is a temperature swing absorption-desorption process, and the high-temperature sensitivity of the ln KcAmCOO- value is of vital importance in attaining cost-efficient processes.
-
CO2 absorption into loaded aqueous MEA solutions: Kinetics assessment using penetration theory
International Journal of Greenhouse Gas Control, 2016Co-Authors: Koteswara Rao Putta, Hallvard F. Svendsen, Diego Di Domenico Pinto, Hanna K. KnuutilaAbstract:Abstract Improved kinetic models based on penetration theory for CO2 capture process by aqueous Monoethanolamine (MEA) solution are developed within MATLAB software in this study. Base contributions of major bases MEA and H2O present in the solution are considered in the Carbamate Formation reaction and termolecular reaction mechanism is used for Carbamate Formation. Both concentration based and activity based kinetic models are valid over the temperature range of 293–343 K, CO2 loading range of 0–0.5. The concentration based kinetic model is valid for MEA concentrations up to 5 M and activity based kinetic model is valid up to 9 M MEA. The developed kinetic models are validated with experimental absorption data from strings of discs, wetted wall column and laminar jet absorber. Both models predict absorption rates as well as desorption rates with good accuracy.
-
experimental study on Carbamate Formation in the amp co2 h2o system at different temperatures
Chemical Engineering Science, 2014Co-Authors: Arlinda F. Ciftja, Ardi Hartono, Hallvard F. SvendsenAbstract:Abstract Carbamate Formation in the 30 wt% of 2-amino-2-methyl-1-propanol (AMP) system at different CO 2 loadings and temperatures was studied via nuclear magnetic resonance (NMR) spectroscopy. The results indicate that the main species in this system are AMP/AMPH + , AMPCO 2 − and HCO 3 − /CO 3 2− . The Carbamate was also observed at low loadings and the apparent Carbamate stability constant was estimated based on the experimental concentrations of the species from NMR analysis. Carbamate Formation was found to have weak temperature dependence in the range tested (25–45 °C). To distinguish within the AMP/AMPH + and HCO 3 − /CO 3 2− pairs, the amine protonation constant, the dissociation constant of carbonic acid from literature, and pH measurements for different ionic strengths were all employed. All the data were correlated with ionic strength and temperature. The accuracy of the Carbamate stability constant determined from the concentration measurements will depend on p K a , ionic strength ( I ) used to calculate the speciation and on the uncertainty in the species concentration determinations from NMR, particularly for the Carbamate species at low CO 2 loadings and high temperature.
-
Experimental study on Carbamate Formation in the AMP–CO2–H2O system at different temperatures
Chemical Engineering Science, 2014Co-Authors: Arlinda F. Ciftja, Ardi Hartono, Hallvard F. SvendsenAbstract:Abstract Carbamate Formation in the 30 wt% of 2-amino-2-methyl-1-propanol (AMP) system at different CO 2 loadings and temperatures was studied via nuclear magnetic resonance (NMR) spectroscopy. The results indicate that the main species in this system are AMP/AMPH + , AMPCO 2 − and HCO 3 − /CO 3 2− . The Carbamate was also observed at low loadings and the apparent Carbamate stability constant was estimated based on the experimental concentrations of the species from NMR analysis. Carbamate Formation was found to have weak temperature dependence in the range tested (25–45 °C). To distinguish within the AMP/AMPH + and HCO 3 − /CO 3 2− pairs, the amine protonation constant, the dissociation constant of carbonic acid from literature, and pH measurements for different ionic strengths were all employed. All the data were correlated with ionic strength and temperature. The accuracy of the Carbamate stability constant determined from the concentration measurements will depend on p K a , ionic strength ( I ) used to calculate the speciation and on the uncertainty in the species concentration determinations from NMR, particularly for the Carbamate species at low CO 2 loadings and high temperature.
Moetaz I. Attalla - One of the best experts on this subject based on the ideXlab platform.
-
Kinetics and mechanism of Carbamate Formation from CO2(aq), carbonate species, and monoethanolamine in aqueous solution.
The Journal of Physical Chemistry A, 2009Co-Authors: Nichola Mccann, Duong T. Phan, Xiaoguang Wang, William Conway, Robert C. Burns, Moetaz I. Attalla, Graeme Puxty, Marcel MaederAbstract:Removal of carbon dioxide from fossil-based power generation is a potentially useful technique for the reduction of greenhouse gas emissions. Reversible interaction with aqueous amine solutions is most promising. In this process, the Formation of Carbamates is an important reaction of carbon dioxide. In this contribution, a detailed molecular reaction mechanism for the Carbamate Formation between MEA (monoethanolamine) and dissolved CO2 as well as carbonate species in aqueous solution is presented. There are three parallel, reversible reactions of the free amine with CO2, carbonic acid, and the bicarbonate ion; the relative importance of the three paths is strongly pH dependent. Kinetic and equilibrium measurements are based on 1H NMR and stopped-flow measurements with rate constants, equilibrium constants, and protonation constants being reported.
-
simulation of enthalpy and capacity of co2 absorption by aqueous amine systems
Industrial & Engineering Chemistry Research, 2008Co-Authors: Nichola Mccann, And Marcel Maeder, Moetaz I. AttallaAbstract:A model has been developed to predict the CO2 capacity of amine-based solvent systems as well as the enthalpy associated with absorption/desorption. This model can be used to accurately predict the behavior of well-characterized solvent systems under a range of different conditions. Alternatively, the model can be used to estimate the properties of less well-defined systems as part of an initial rapid screening procedure. Investigation into the effects of varying amine basicity and degree of Carbamate Formation indicates that there is considerable room for improvement on the standard MEA (monoethanolamine) system in terms of both capture capacity and enthalpy of CO2 desorption.
Nichola Mccann - One of the best experts on this subject based on the ideXlab platform.
-
A calorimetric study of Carbamate Formation
The Journal of Chemical Thermodynamics, 2011Co-Authors: Nichola Mccann, Marcel Maeder, Hans HasseAbstract:Abstract Post combustion capture of CO2 (PCC) is currently one of the leading technologies for the reduction of green house gas emissions from power plants. The most common PCC process is based on the absorption of CO2 into aqueous amine solutions. CO2 absorption involves several parallel reactions including hydration of CO2; deprotonation of carbonic acid; protonation of the amine; and Formation of Carbamate. The extent to which each reaction proceeds is dependent on the conditions of absorption (or desorption), as well as the associated equilibrium constants. All reactions other than Carbamate Formation have been extensively investigated previously. The investigation of Carbamate Formation is more complex, as it cannot be studied in the absence of other, simultaneous reactions. In particular, the enthalpy of Carbamate Formation has been determined previously only from the temperature dependence of equilibrium constants, but this methodology is not robust. In this contribution, we use calorimetry and advanced model-based data analysis methods for the unravelling of the thermo-chemistry relevant to PCC and specifically directly determine the reaction enthalpy for Carbamate Formation. The reaction enthalpies of Carbamate Formation and amine protonation were measured in dilute aqueous solution at 298 K using isothermal titration calorimetry (ITC) for monoethanolamine (MEA), diethanolamine (DEA), and ammonia (NH3). The enthalpy of protonation was also measured for carbonate and bicarbonate. The re-determined protonation constants of the carbonate species and the three amines are in excellent agreement with previously reported results. No measured enthalpies of Carbamate Formation have been reported previously. For the Carbamate Formation reaction HCO 3 - + R ′ RNH ↔ R ′ RNCO 2 - , the following reaction enthalpies were determined: MEA, −29.7 ± 0.1 kJ/mol; DEA, −23.7 ± 0.9 kJ/mol, and NH3, −27.6 ± 0.9 kJ/mol. The results are in good agreement with, but much more precise and robust than estimated values reported in the literature.
-
Kinetics and mechanism of Carbamate Formation from CO2(aq), carbonate species, and monoethanolamine in aqueous solution.
The Journal of Physical Chemistry A, 2009Co-Authors: Nichola Mccann, Duong T. Phan, Xiaoguang Wang, William Conway, Robert C. Burns, Moetaz I. Attalla, Graeme Puxty, Marcel MaederAbstract:Removal of carbon dioxide from fossil-based power generation is a potentially useful technique for the reduction of greenhouse gas emissions. Reversible interaction with aqueous amine solutions is most promising. In this process, the Formation of Carbamates is an important reaction of carbon dioxide. In this contribution, a detailed molecular reaction mechanism for the Carbamate Formation between MEA (monoethanolamine) and dissolved CO2 as well as carbonate species in aqueous solution is presented. There are three parallel, reversible reactions of the free amine with CO2, carbonic acid, and the bicarbonate ion; the relative importance of the three paths is strongly pH dependent. Kinetic and equilibrium measurements are based on 1H NMR and stopped-flow measurements with rate constants, equilibrium constants, and protonation constants being reported.
-
simulation of enthalpy and capacity of co2 absorption by aqueous amine systems
Industrial & Engineering Chemistry Research, 2008Co-Authors: Nichola Mccann, And Marcel Maeder, Moetaz I. AttallaAbstract:A model has been developed to predict the CO2 capacity of amine-based solvent systems as well as the enthalpy associated with absorption/desorption. This model can be used to accurately predict the behavior of well-characterized solvent systems under a range of different conditions. Alternatively, the model can be used to estimate the properties of less well-defined systems as part of an initial rapid screening procedure. Investigation into the effects of varying amine basicity and degree of Carbamate Formation indicates that there is considerable room for improvement on the standard MEA (monoethanolamine) system in terms of both capture capacity and enthalpy of CO2 desorption.
Hiroyasu Furukawa - One of the best experts on this subject based on the ideXlab platform.
-
designed amyloid fibers as materials for selective carbon dioxide capture
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Hexiang Deng, Hiroyasu Furukawa, Omar M Yaghi, David EisenbergAbstract:New materials capable of binding carbon dioxide are essential for addressing climate change. Here, we demonstrate that amyloids, self-assembling protein fibers, are effective for selective carbon dioxide capture. Solid-state NMR proves that amyloid fibers containing alkylamine groups reversibly bind carbon dioxide via Carbamate Formation. Thermodynamic and kinetic capture-and-release tests show the Carbamate Formation rate is fast enough to capture carbon dioxide by dynamic separation, undiminished by the presence of water, in both a natural amyloid and designed amyloids having increased carbon dioxide capacity. Heating to 100 °C regenerates the material. These results demonstrate the potential of amyloid fibers for environmental carbon dioxide capture.
Arlinda F. Ciftja - One of the best experts on this subject based on the ideXlab platform.
-
experimental study on Carbamate Formation in the amp co2 h2o system at different temperatures
Chemical Engineering Science, 2014Co-Authors: Arlinda F. Ciftja, Ardi Hartono, Hallvard F. SvendsenAbstract:Abstract Carbamate Formation in the 30 wt% of 2-amino-2-methyl-1-propanol (AMP) system at different CO 2 loadings and temperatures was studied via nuclear magnetic resonance (NMR) spectroscopy. The results indicate that the main species in this system are AMP/AMPH + , AMPCO 2 − and HCO 3 − /CO 3 2− . The Carbamate was also observed at low loadings and the apparent Carbamate stability constant was estimated based on the experimental concentrations of the species from NMR analysis. Carbamate Formation was found to have weak temperature dependence in the range tested (25–45 °C). To distinguish within the AMP/AMPH + and HCO 3 − /CO 3 2− pairs, the amine protonation constant, the dissociation constant of carbonic acid from literature, and pH measurements for different ionic strengths were all employed. All the data were correlated with ionic strength and temperature. The accuracy of the Carbamate stability constant determined from the concentration measurements will depend on p K a , ionic strength ( I ) used to calculate the speciation and on the uncertainty in the species concentration determinations from NMR, particularly for the Carbamate species at low CO 2 loadings and high temperature.
-
Experimental study on Carbamate Formation in the AMP–CO2–H2O system at different temperatures
Chemical Engineering Science, 2014Co-Authors: Arlinda F. Ciftja, Ardi Hartono, Hallvard F. SvendsenAbstract:Abstract Carbamate Formation in the 30 wt% of 2-amino-2-methyl-1-propanol (AMP) system at different CO 2 loadings and temperatures was studied via nuclear magnetic resonance (NMR) spectroscopy. The results indicate that the main species in this system are AMP/AMPH + , AMPCO 2 − and HCO 3 − /CO 3 2− . The Carbamate was also observed at low loadings and the apparent Carbamate stability constant was estimated based on the experimental concentrations of the species from NMR analysis. Carbamate Formation was found to have weak temperature dependence in the range tested (25–45 °C). To distinguish within the AMP/AMPH + and HCO 3 − /CO 3 2− pairs, the amine protonation constant, the dissociation constant of carbonic acid from literature, and pH measurements for different ionic strengths were all employed. All the data were correlated with ionic strength and temperature. The accuracy of the Carbamate stability constant determined from the concentration measurements will depend on p K a , ionic strength ( I ) used to calculate the speciation and on the uncertainty in the species concentration determinations from NMR, particularly for the Carbamate species at low CO 2 loadings and high temperature.
-
Selection of Amine Amino Acids Salt Systems for CO2 Capture
Energy Procedia, 2013Co-Authors: Arlinda F. Ciftja, Ardi Hartono, Hallvard F. SvendsenAbstract:Abstract Several amino acids including Glycine, L-Alanine, Taurine, Sarcosine, L-Serine, L-Proline, blended with monoethanolamine (MEA) in presence of different amounts of CO2 were qualitatively and quantitatively studied by NMR spectroscopy. 1D and 2D NMR were employed to qualitatively determine the Carbamate Formation from the amine group of the amino acids. All species were identified and reported in this work. The preliminary quantitative 13C NMR have shown that the highest Carbamate Formation occurs in the loaded taurine –MEA system and the lowest in the loaded L-alanine – MEA system. In the present work, the complete neutralization of sarcosine with MEA did not occur because of the Carbamate Formation of the amine group of the MEA.
-
Carbamate Formation in Aqueous - diamine - CO2 Systems
Energy Procedia, 2013Co-Authors: Arlinda F. Ciftja, Ardi Hartono, Hallvard F. SvendsenAbstract:Abstract Qualitative NMR spectroscopy was used to study the species formed during CO 2 absorption in aqueous solution of diamines. Three different systems, consisting of primary (ethylenediamine), primary/secondary (3-(Methylamino) propylamine) and secondary (piperazine) diamines were studied by 13 C NMR and the main products were identified based on various 1D and 2D NMR techniques. The main compounds were observed and assigned to (primary/ secondary) Carbamate, diCarbamate and carbonate/bicarbonate. The highest concentration of carbonate/bicarbonate and diCarbamate were observed in the PZ/CO 2 /H 2 O followed by MAPA/CO 2 /H 2 O and EDA/CO 2 /H 2 O. Both 1H and 13 C NMR spectroscopy was used to quantitatively determine the speciation of amines but 13 C-NMR, although slower, has the potential of being more accurate than the 1H-NMR. The diamines studied in the present work were found to have high CO 2 absorption capacity compared to other amines described in the literature. This indicates that they are interesting for the further investigation.