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Ali Haghtalab - One of the best experts on this subject based on the ideXlab platform.
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solubility and thermodynamic modeling of hydrogen sulfide in aqueous diisopropanolamine 2 amino 2 methyl 1 propanol piperazine solution at high pressure
The Journal of Chemical Thermodynamics, 2015Co-Authors: Ali Haghtalab, Amin IzadiAbstract:Abstract Natural gas as a clean source of energy contains several contaminates such as CO2 and H2S that is treated through a natural gas purification unit in gas industry. Moreover, for design and construction of gas contactor equipment, it is necessary to obtain experimental values of solubility for H2S and CO2 in aqueous amine/Alkanolamines. In this work, the solubility of H2S in the blended aqueous diisopropanolamine (DIPA), 2-amino-2-methyl-1-propanol (AMP) and piperazine (Pz) are measured using a static high pressure apparatus through volumetric method. The values are measured at fixed 45 mass per cent of total amine so that the solubility of H2S in the present system is investigated under isothermal conditions at T = (313.15, 328.15 and 343.15) K and in the pressure range of (0.1 to 2.1) MPa. The experimental results are presented as the partial pressure of H2S against acid gas loading (moles H2S per total moles of amine). Also for modeling the solubility of H2S in the blended amine/Alkanolamines, the Electrolyte-NRTL activity coefficient function is applied to the correlation and prediction of the partial pressure of H2S versus the acid gas loading. Considering the present results at the given conditions, it is observed that in the low gas loading region, the effect of enhancing Pz on the solubility of H2S is very low, but at high gas loading the absorption of H2S is intensified by enhancing mass fraction of Pz in Alkanolamine.
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simultaneous measurement solubility of carbon dioxide hydrogen sulfide into aqueous blends of Alkanolamines at high pressure
Fluid Phase Equilibria, 2014Co-Authors: Ali Haghtalab, Amin IzadiAbstract:Abstract Treatment of the sour natural gas is a major step in natural gas processing so that the acid gases such as H2S and CO2 are removed from natural gas stream. The acid gases are harmful to environment and destroy the production equipment so that their presence in gas stream leads to corrosion and lowering heating value. On the other hand, for reliable and optimum design of separation equipment, primarily sufficient and accurate equilibrium data of the acid gases solubility in the aqueous Alkanolamines is required. In this work, the simultaneous solubility of the H2S + CO2 in the Alkanolamine mixtures is measured at 343 K and total pressure range of 0.1–2.1 MPa. The blends are studied as the aqueous mixtures of N-methyldiethanolamine (MDEA) + 2-amino-2-methyl-1-propanol (AMP) + Piperazine (Pz) and the aqueous mixtures of diisopropanolamine (DIPA), AMP and Pz. For the acid gas solubility measurements, a high pressure static apparatus is used through a volumetric method. The mass fraction of the total Alkanolamine is fixed at 0.45 and the results are presented as the partial pressure of each acid gas against its loading (mole acid gas/total mole amine) and mole fraction. The influence of the AMP and Pz on the aqueous DIPA-based and MDEA-based systems are studied so that it is observed that the absorption of the CO2 in the aqueous Alkanolamine enhances through separate blending of the AMP and Pz with the aqueous system of MDEA or DIPA and the absorption of the H2S reduces in both of the aqueous DIPA-based and MDEA-based systems.
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solubility and density of carbon dioxide in different aqueous Alkanolamine solutions blended with 1 butyl 3 methylimidazolium acetate ionic liquid at high pressure
Journal of Molecular Liquids, 2013Co-Authors: Abolfazl Shojaeian, Ali HaghtalabAbstract:Abstract Using a static high pressure equilibrium cell, the new set of the experimental data is obtained for solubility of carbon dioxide in the aqueous mixtures of different type of Alkanolamines such as N-methyldiethanolamine (MDEA), Diethanolamine (DEA), Diisopropanolamine (DIPA), 2-amino-2-methyl-1-propanol (AMP), and 1-butyl-3-methylimidazolium acetate ionic liquid [bmim] [acetate]. The solubility of CO2 in the aqueous MDEA + [bmim][acetate], DEA + [bmim][acetate], DIPA + [bmim][acetate] and AMP + [bmim][acetate] solutions with 0–10 wt% of ionic liquid and 30–40 wt% Alkanolamine are carried out at 1 to 40 bar and 323.15 K. Moreover, the temperature dependency of density for these solutions is measured from 293.15 to 343.15 K with 10 K intervals. The results of the CO2 solubility are represented by partial pressure of CO2 against the loading and mole fraction of CO2. The solubility of the CO2 in all of the aqueous Alkanolamine + ionic liquid solutions decreases with increasing weight percent of ionic liquid. Also, the results show that the maximum decrease of CO2 loading belongs to addition of [bmim] [acetate] to the aqueous MDEA solution. Finally, the results of density of the Alkanolamine + ionic liquid solutions present that the density enhances with increasing concentration of [bmim][acetate] and reduces linearly with enhancing temperature.
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modeling solubility of acid gases in Alkanolamines using the nonelectrolyte wilson nonrandom factor model
Fluid Phase Equilibria, 2010Co-Authors: Ali Haghtalab, Abolfazl ShojaeianAbstract:Abstract The nonelectrolyte Wilson-nonrandom factor local composition model (N-Wilson-NRF) by Haghtalab and Mazloumi is applied for modeling the vapor–liquid equilibrium of the acid gases (CO2 and H2S)–Alkanolamine–water systems. The model is used to calculate the nonideality of species in liquid phase through the activity coefficient equations. In this work, we use the N-Wilson-NRF model for short-range forces in the aqueous electrolyte system of Alkanolamines by using the concept of ion-pair. For the long-range interaction the Pitzer–Debye–Huckel theory is applied. The model is used to correlation of the solubility data of CO2 and H2S in aqueous monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA) and 2-amino-2methyl-1-propanol (AMP) systems over wide range of temperature (0–140 °C), partial pressure (0.001–1000 kPa) and acid gases loading (0.001–1.0 mol gas/mol amine). To show the predictability of the model, the interaction parameters without any additional adjustable parameters are used to predict the solubility of CO2 in aqueous AMP solution at different conditions. The results of the model show a very good agreement with the experimental data.
Gopinatha Suresh Kumar - One of the best experts on this subject based on the ideXlab platform.
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chelerythrine lysozyme interaction spectroscopic studies thermodynamics and molecular modeling exploration
Physical Chemistry Chemical Physics, 2015Co-Authors: Chandrima Jash, Pritha Basu, Pavan V Payghan, Nanda Ghoshal, Gopinatha Suresh KumarAbstract:The binding of the iminium and Alkanolamine forms of chelerythrine to lysozyme (Lyz) was investigated by spectroscopy and docking studies. The thermodynamics of the binding was studied by calorimetry. Spectroscopic evidence suggested that Trp-62 and Trp-63 in the β-domain of the protein are closer to the binding site; moreover, the binding site was at a distance of 2.27 and 2.00 nm from the iminium and Alkanolamine forms, respectively, according to the Forster theory of non-radiation energy transfer. The equilibrium binding constants for the iminium and Alkanolamine forms at 298 K were evaluated to be 1.29 × 105 and 7.79 × 105 M−1, respectively. The binding resulted in an alteration of the secondary structure of the protein with a distinct reduction of the helical organization. The binding of iminium was endothermic, involving electrostatic and hydrophobic interactions, while that of Alkanolamine form was exothermic and dominated by hydrogen bonding interactions. Docking studies provided the atomistic details pertaining to the binding of both forms of chelerythrine and supported the higher binding in favour of the Alkanolamine over the iminium. Furthermore, molecular dynamics study provided accurate insights regarding the binding of both chelerythrine forms in accordance with the experimental results obtained. Chelerythrine binding pocket involves the catalytic region and aggregation prone K-peptide region, which are sandwiched between one another. Overall, these results suggest that both the forms of the alkaloid bind to the protein but the neutral form has higher affinity than the cationic form.
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structural and thermodynamic studies on the interaction of iminium and Alkanolamine forms of sanguinarine with hemoglobin
Journal of Physical Chemistry B, 2014Co-Authors: Soumitra Hazra, Gopinatha Suresh KumarAbstract:Binding of the iminium and Alkanolamine forms of the benzophenanthridine anticancer alkaloid sanguinarine to hemoglobin (Hb) was investigated by absorbance, fluorescence, and circular dichroism spectral techniques, and by calorimetry. The binding affinity of the charged iminium was found to be of the order of 106 M–1, higher by one order than that of the neutral Alkanolamine, from the analysis of the absorbance data. The fluorescence spectral data revealed that the quenching of Hb fluorescence by both forms of sanguinarine is due to the formation of a complex in the ground state and is of an unusual, static nature. Thermodynamic data revealed that the binding of the iminium form was exothermic in nature while that of the Alkanolamine was endothermic; the former case predominantly involved electrostatic and hydrogen bonding interactions but the latter was dominated by mostly hydrophobic interactions. Calculation of the molecular distances (r) between the donor (β-Trp37) and acceptor (iminium and alkanolami...
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Structural and Thermodynamic Studies on the Interaction of Iminium and Alkanolamine Forms of Sanguinarine with Hemoglobin
2014Co-Authors: Soumitra Hazra, Gopinatha Suresh KumarAbstract:Binding of the iminium and Alkanolamine forms of the benzophenanthridine anticancer alkaloid sanguinarine to hemoglobin (Hb) was investigated by absorbance, fluorescence, and circular dichroism spectral techniques, and by calorimetry. The binding affinity of the charged iminium was found to be of the order of 106 M–1, higher by one order than that of the neutral Alkanolamine, from the analysis of the absorbance data. The fluorescence spectral data revealed that the quenching of Hb fluorescence by both forms of sanguinarine is due to the formation of a complex in the ground state and is of an unusual, static nature. Thermodynamic data revealed that the binding of the iminium form was exothermic in nature while that of the Alkanolamine was endothermic; the former case predominantly involved electrostatic and hydrogen bonding interactions but the latter was dominated by mostly hydrophobic interactions. Calculation of the molecular distances (r) between the donor (β-Trp37) and acceptor (iminium and Alkanolamine) according to Förster’s theory suggests both forms of the alkaloid to be bound close to β-Trp37 at the α1β2 interface of the protein. The iminium form induced greater secondary structural changes in Hb than the Alkanolamine as revealed by synchronous fluorescence, circular dichroism and three-dimensional fluorescence spectroscopic studies. These results are consistent with a stronger binding of the iminium over the Alkanolamine form. Nevertheless, the hydrophobic probe ANS was displaced from hemoglobin more easily by the Alkanolamine form than by the iminium. The study showed that Hb binds more strongly to the biologically active iminium form than the Alkanolamine, in contrast to the stronger binding of the latter to plasma protein serum albumin. Overall, this study presents insights on the interaction dynamics and energetics of the binding of the two forms of sanguinarine to hemoglobin
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study on the thermodynamics of the binding of iminium and Alkanolamine forms of the anticancer agent sanguinarine to human serum albumin
The Journal of Chemical Thermodynamics, 2012Co-Authors: Maidul Hossain, Asma Yasmeen Khan, Gopinatha Suresh KumarAbstract:Abstract Sanguinarine is an anticancer plant alkaloid that can exist in the charged iminium and neutral Alkanolamine forms. The thermodynamics of the interaction of the two forms with human serum albumin was investigated using calorimetric techniques, and the data supplemented with circular dichroism and spectrofluorimetric studies. The thermodynamic results show that there is only one class of binding for sanguinarine on HSA. The equilibrium constant was four times higher for the Alkanolamine (Ka = 2.18 · 105 M−1) than for iminium (Ka = 5.97 · 104 M−1). The binding was enthalpy driven for iminium and favoured by both a negative enthalpy and a stronger favourable entropy contribution for the Alkanolamine. Temperature dependent calorimetric data yielded values of Δ C p ∘ that are consistent with the involvement of different molecular forces in the complexation of the two forms of sanguinarine to HSA. The fluorescence quenching data suggest a static quenching mechanism. Synchronous fluorescence and circular dichroic data are consistent with a conformational change in the protein on binding that was also higher for the Alkanolamine form.
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interaction of the anticancer plant alkaloid sanguinarine with bovine serum albumin
PLOS ONE, 2011Co-Authors: Maidul Hossain, Asma Yasmeen Khan, Gopinatha Suresh KumarAbstract:Background: Interaction of the iminium and Alkanolamine forms of sanguinarine with bovine serum albumin (BSA) was characterized by spectroscopic and calorimetric techniques. Methodology/Principal Findings: Formation of strong complexes of BSA with both iminium and Alkanolamine forms was revealed from fluorescence quenching of sanguinarine. Binding parameters calculated from Stern-Volmer quenching method revealed that the neutral Alkanolamine had higher affinity to BSA compared to the charged iminium form. Specific binding distances of 3.37 and 2.38 nm between Trp 212 (donor) and iminium and Alkanolamine forms (acceptor), respectively, were obtained from Forster resonance energy transfer studies. Competitive binding using the site markers warfarin and ibuprofen, having definite binding sites, demonstrated that both forms of sanguinarine bind to site I (subdomain IIA) on BSA. Sanguinarine binding alters protein conformation by reducing the a-helical organization and increasing the coiled structure, indicating a small but definitive partial unfolding of the protein. Thermodynamic parameters evaluated from isothermal titration calorimetry suggested that the binding was enthalpy driven for the iminium form but favoured by negative enthalpy and strong favourable entropy contributions for the Alkanolamine form, revealing the involvement of different molecular forces in the complexation. Conclusions/Significance: The results suggest that the neutral Alkanolamine form binds to the protein more favourably compared to the charged iminium, in stark contrast to the reported DNA binding preference of sanguinarine.
Arturo Trejo - One of the best experts on this subject based on the ideXlab platform.
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corrosion in aqueous solution of two Alkanolamines with co2and h2s n methyldiethanolamine diethanolamine at 393 k
Industrial & Engineering Chemistry Research, 2008Co-Authors: Rafael Eustaquiorincon, Maria Esther Rebolledolibreros, Arturo Trejo, Rene MolnarAbstract:In this work we have used an apparatus constructed in our laboratory to systematically study the corrosion rate on metals and evaluate specialty chemical products for preventing metal corrosion in industrial plants. We performed experimental studies on the effect of specific variables on corrosion rates over carbon steel, such as pressure, concentration of Alkanolamines in aqueous solution, and amount of acid gases (CO2 and H2S). The technique utilized to evaluate the corrosion rate is the well-known weight loss method. With the experimental apparatus and method developed in this work we have determined the corrosion rate of AISI 1010 carbon steel in aqueous solutions of known concentration of N-methyldiethanolamine (MDEA) and diethanolamine (DEA), individually, with and without acid gases, and in different Alkanolamine blends with total Alkanolamine mass fraction in the range 15−60%, with mass ratios of MDEA/DEA of 3.5/1 and 2/1, with the addition of different amounts of H2S and CO2 at a pressure range o...
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surface tension and foam behaviour of aqueous solutions of blends of three Alkanolamines as a function of temperature
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2007Co-Authors: Jacinto Aguilahernandez, Arturo Trejo, Blanca E GarciafloresAbstract:Abstract We have determined the equilibrium surface tension for aqueous solutions of three Alkanolamines composed of 32.5 mass% N-methyldiethanolamine (MDEA) and 12.5 mass% diethanolamine (DEA) with the addition of 2, 4, 6, 8, and 10 mass% of 2-amino-2-methyl-1-propanol (AMP), at 303.15, 308.15, 313.15, 318.15, 323.15, 328.15, 333.15, 338.15, and 343.15 K. We have also determined experimentally the foaming properties for the same aqueous solutions of three Alkanolamines as in the surface tension study, at 303.15, 313.15, 323.15, 333.15, and 343.15 K. In order to elucidate the effect of the concentration of AMP on the two studied properties we have also determined experimentally the foamability of the aqueous system of two Alkanolamines composed of 32.5 mass% MDEA + 12.5 mass% DEA, at 303.15, 313.15, 323.15, 333.15, and 343.15 K, and for the two binary systems composed of DEA + water and MDEA + water, at concentrations of 10, 20, 30, 40, and 50 mass% of the Alkanolamine, at 313.15, 323.15, 333.15, and 343.15 K. In the temperature range studied, the experimental surface tension values of the aqueous blends of three Alkanolamines decrease linearly both as the AMP concentration increases and as the temperature increases. The surface tension results for the aqueous solutions of blends of three Alkanolamines were correlated simultaneously as a function of temperature and AMP concentration. The foamability results for the quaternary systems reveal that the high surface activity of AMP allows it to act favorably as antifoaming agent in the concentration range of 4–10 mass%, at 303.15, 313.15, and 323.15 K. The experimental behaviour of the different studied systems show that the high surface activity of AMP leads to low surface tension, large surface adsorption, large limiting elasticity, and very low foamability for aqueous systems with one, two or three Alkanolamines in which it is present as a component.
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gas solubility of co2 in aqueous solutions of n methyldiethanolamine and diethanolamine with 2 amino 2 methyl 1 propanol
Fluid Phase Equilibria, 2004Co-Authors: Maria Esther Rebolledolibreros, Arturo TrejoAbstract:Gas solubility of carbon dioxide in an aqueous solution of 32.5 wt.% N-methyldiethanolamine and 12.5 wt.% diethanolamine with 4, 6, and 10 wt.% 2-amino-2-methyl-1-propanol has been measured, at 313.15, 343.15, and 393.15 K, over a range of pressure from 3 to 2000 kPa, using a chromatographic method for analysis of the liquid phase. The results of the gas solubility are given as the partial pressure of CO 2 against its mole ratio α (mol CO2/mol Alkanolamine) and its mole fraction at each temperature studied. The solubility of CO 2 in all the systems studied decreases with an increase in temperature and increases with an increase in the partial pressure of CO 2 at a given temperature and it is a function of the concentration of the mixture of Alkanolamines in solution. The enthalpy of solution of CO 2 has been calculated from the experimental solubility data. © 2004 Elsevier B.V. All rights reserved.
Geert Versteeg - One of the best experts on this subject based on the ideXlab platform.
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Combined Effect of Temperature and pKa on the Kinetics of Absorption of Carbon Dioxide in Aqueous Alkanolamine and Carbonate Solutions with Carbonic Anhydrase
Industrial & Engineering Chemistry Research, 2016Co-Authors: S. Martijn Oversteegen, Geert VersteegAbstract:In present work the absorption of carbon dioxide in aqueous N-methyldiethanolamine, N,N-dimethylethanolamine, and triisopropanolamine solutions with and without the enzyme carbonic anhydrase has been studied in a stirred cell reactor at temperatures varying between 278 and 313 K, at an Alkanolamine concentration of 1 kmol m–3 and carbonic anhydrase concentrations ranging from 0 to 2.4 kg m–3, respectively. The experimental data from these experiments have been used to fit the obtained rate constant for the enzymatic CO2 hydration to the Bronsted relation: ln(k) = A(pKa) + B + C/T. In addition to the carbon dioxide absorption in the three tertiary Alkanolamines, the absorption of carbon dioxide in next three solvents had been studied: 0.3 kmol m–3 potassium carbonate, 0.3 kmol m–3 sodium carbonate, and 0.2 kmol m–3 2-amino-2-methyl-1-propanol. The kinetics from these solvents are well predicted by the relation fitted to the data of the tertiary amines only.
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Carbon dioxide removal by Alkanolamines in aqueous organic solvents: A method for enhancing the desorption process
Energy Procedia, 2011Co-Authors: Espen S. Hamborg, Peter W. J. Derks, Edwin P. Van Elk, Geert VersteegAbstract:Abstract Process concepts of using Alkanolamines in aqueous organic solvents have been evaluated by experimental work and process simulations using the Procede Process Simulator. N-methyldiethanolamine (MDEA), methanol, and ethanol were chosen as the respective Alkanolamine and organic compounds in the current work. In previous work, the dissociation constants of protonated MDEA at infinite dilution in methanol–water and ethanol–water solvents and the initial mass transfer rates of CO 2 in 3 kmol m −3 MDEA in methanol–water and ethanol–water solvents were determined. In the current work, experimental values of the CO 2 vapor liquid equilibria in 3 kmol m −3 MDEA have been determined in methanol–water and ethanol–water solvents. The experimentally determined results have been implemented into the Procede Process Simulator, which has been used to simulate a CO 2 removal plant with 90% CO 2 removal based on the specification of the flue gas of an 827 MWe pulverized coal fired power plant. A solvent of 3 kmol m −3 MDEA in aqueous methanol solution was considered for conceptual purposes. The results indicatively show a maximum decrease in the reboiler duty of the desorber of about 7.5% at methanol fractions of about 0.06 compared to purely aqueous solutions and a reboiler temperature decrease with increasing methanol fractions. Further experimental results are, however, necessary in order to more precisely simulate CO 2 removal processes by Alkanolamines in aqueous organic solvents.
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the effect of aqueous organic solvents on the dissociation constants and thermodynamic properties of Alkanolamines
Fluid Phase Equilibria, 2010Co-Authors: Espen S. Hamborg, Coen Van Aken, Geert VersteegAbstract:Abstract The dissociation constants of protonated monoethanolamine and N-methyldiethanolamine have been determined in methanol–water, ethanol–water, and t-butanol–water solvents. The alcohol mole fractions were ranging from 0.2 to 0.95 and the temperatures from 283 to 323 K, 283 to 333 K, and at 298.15 K, respective to the different solvents. The experimental results are reported with the standard state thermodynamic properties. The basic strength of the protonated Alkanolamine decreases with decreasing dielectric constant and increasing temperature of the solvent. By using the dissociation constants of the Alkanolamines in pure water, it is shown that a Born treatment alone is not able to estimate the dissociation constants when the composition of the solvent is changed to an aqueous organic mixture.
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kinetics of the reaction of co2 with aqueous potassium salt of taurine and glycine
Aiche Journal, 2003Co-Authors: Paramasivam Senthil Kumar, J A Hogendoorn, Geert Versteeg, Paul FeronAbstract:The kinetics of the reaction between CO2 and aqueous potassium salts of taurine and glycine was measured at 295 K in a stirred-cell reactor with a flat gas-liquid interface. For aqueous potassium taurate solutions, the temperature effect on the reaction kinetics was measured at 285 and 305 K. Unlike aqueous primary Alkanolamines, the partial reaction order in amino acid salt changes from one at low salt concentration to approximately 1.5 at salt concentrations as high as 3,000 mol·m-3. At low salt concentrations, the measured apparent rate constant (kapp) for potassium glycinate is comparable to the values in literature. In the absence of reliable information in the literature on the kinetics and mechanism of the reaction, the applicability of the zwitterion and termolecular mechanism (proposed originally for Alkanolamines) was explored. For the zwitterion mechanism, the forward second-order reaction rate constant (k2) of the CO2 reaction with amino acid salt seems to be much higher than for Alkanolamines of similar basicity, indicating that the Bronsted plot for amino acid salts might differ from that of Alkanolamines. The contribution of water to the deprotonation of zwitterion seems to be more significant than reported values for aqueous secondary Alkanolamines.
Faical Larachi - One of the best experts on this subject based on the ideXlab platform.
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corrosion behavior of carbon steel in Alkanolamine room temperature ionic liquid based co2 capture systems
Industrial & Engineering Chemistry Research, 2012Co-Authors: Muhammad Hasiburrahman, Hana Bouteldja, Pascal Fongarland, Mohamed Siaj, Faical LarachiAbstract:To address the drawbacks of aqueous Alkanolamine based state-of-the-art technology for industrial scale carbon dioxide capture, among a number of options, Alkanolamine/room-temperature ionic liquid (RTIL) systems are also being tested as a likely replacement. These new schemes seem to be a better alternative to hamper corrosion occurrence. Omission of the aqueous phase marks abolition of probable oxidizing species mainly responsible for corrosion in water-based chemical absorption processes. In the present study, the corrosion phenomenon in amine/room-temperature ionic liquid blends comprised of Alkanolamine/s (monoethanolamine, 2-amino-2-methyl-1-propanol, diethanolamine, N-methyldiethanolamine) and hydrophilic room-temperature ionic liquid ([BMIM][BF4], [EMIM][BF4], and [EMIM][Otf]) has been investigated by systematically probing the effect of amine/RTIL type, process temperature, CO2 loading, presence/absence of oxygen in flue gas, as well as the influence of water content. The analytical techniques ex...