The Experts below are selected from a list of 126 Experts worldwide ranked by ideXlab platform
David J Heldebrant - One of the best experts on this subject based on the ideXlab platform.
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assessing anhydrous Tertiary Alkanolamines for high pressure gas purifications
Industrial & Engineering Chemistry Research, 2013Co-Authors: Paul M Mathias, Louis V Jasperson, David Vonniederhausern, Mark D Bearden, Phillip K Koech, Charles J Freeman, David J HeldebrantAbstract:Anhydrous Tertiary Alkanolamines chemically react with CO2 and H2S, with greater selectivity for the latter. This is in direct contrast to aqueous amine-based solvent systems, which exhibit higher selectivity for CO2 over H2S. Anhydrous Tertiary Alkanolamines exhibit pressure-induced chemical fixation of CO2 to form zwitterionic ammonium alkylcarbonate ionic liquids, while the same Tertiary Alkanolamines react with H2S at atmospheric pressures to form hydrosulfide ionic liquids. This difference in capture pressure implies that certain anhydrous Alkanolamines could be chemically selective for H2S over CO2. We present here the first published vapor–liquid–liquid equilibrium (VLLE) data of anhydrous ethyldiethanolamine (EDEA) with CH4, C3H8, H2S, and CO2 at 10–50 °C measured by the TPx and TPxy methods. The data are modeled in Aspen Plus using an NRTL-with-solvation model. Data trends and the underlying phenomena are discussed for each gas. We also present process simulations that compare anhydrous EDEA’s pe...
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Chemically selective gas sweetening without thermal-swing regeneration
Energy and Environmental Science, 2011Co-Authors: Phillip K Koech, Mark D Bearden, James E. Rainbolt, Feng Zheng, David J HeldebrantAbstract:Natural gas purifications using chemically selective hydrogen sulfide (H2S) sorbents could be more efficient if chemical selectivity for H2S could be maintained without thermal regeneration of the sorbent. We used Tertiary Alkanolamines to reversibly capture H2S in the absence of water to produce hydrosulfide-based ionic liquids in high yield. These alkanolammonium hydrosulfide ionic liquids release H2S by exposure to inert gas or by mild heating. H2S can be rapidly and nearly quantitatively released at ambient temperature from the alkanolammonium hydrosulfide ionic liquids by the addition of nonpolar antisolvents, some of which naturally phase separate from the spent alkanolamine. The antisolvent-induced regeneration of the alkanolamine potentially allows an efficient H2S gas scrubbing process that is chemically selective and can be operated continuously at or near ambient temperature.
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anhydrous Tertiary Alkanolamines as hybrid chemical and physical co2 capture reagents with pressure swing regeneration
Energy and Environmental Science, 2011Co-Authors: James E. Rainbolt, Phillip K Koech, Feng Zheng, Clement R Yonker, Denise Main, Matt L Weaver, John C Linehan, David J HeldebrantAbstract:Anhydrous DMEA, DEEA and DIPEA are found to absorb carbon dioxide under pressure via chemical binding and physical absorption. The chemical CO2-bound derivatives of these materials are zwitterionic alkylcarbonate salts which are characterized by high-pressure 13C NMR. DMEA, DEEA and DIPEA absorb 20 wt.%, 17 wt.% and 16 wt.% carbon dioxide, respectively, at 300 psig (20.6 ATM). An increasing chemical carbon dioxide uptake capacity trend of DMEA > DEEA > DIPEA is observed while the physical CO2 absorption trend is DIPEA > DEEA > DMEA. DMEA captures up to 45 mole % (20 wt.%) of CO2 at 500 psig via both chemical binding and physical absorption. The amount of chemically bound and physically absorbed CO2 is directly linked to the CO2 pressure over the liquid. The zwitterion DMEA-CO2 regenerates CO2 and DMEA upon depressurization, allowing for an economical pressure swing regeneration rather than thermal regeneration. DMEA absorbs/releases CO2 repeatedly with no decline in capacity.
Raphael Idem - One of the best experts on this subject based on the ideXlab platform.
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effect of alkanol chain length of primary Alkanolamines and alkyl chain length of secondary and Tertiary Alkanolamines on their co2 capture activities
Separation and Purification Technology, 2017Co-Authors: Jessica Narkutetteh, Pailin Muchan, Raphael IdemAbstract:Abstract The effect of the alkanol chain length in primary Alkanolamines and the alkyl chain length in secondary and Tertiary Alkanolamines on CO 2 absorption and desorption kinetics, equilibrium CO 2 loading, heat duty, cyclic capacity, and pKa were studied. A selection strategy developed in our earlier work was used to identify potential solvents which could be used in a blend. Based on the strategy, Alkanolamines that had a combination of high absorption parameter and high desorption parameter should be selected. The results of this study showed that, for absorption parameters, longer alkanol chain lengths of primary Alkanolamines and longer alkyl chain lengths of secondary and Tertiary Alkanolamines led to higher equilibrium CO 2 loading and pKa. However, the influence of mass transfer limitations on these positive effects resulted in a maximum trend for initial rate of CO 2 absorption for secondary and Tertiary Alkanolamines. On the other hand, for the desorption parameters, the increase in the chain lengths also caused the generation of larger amounts of bicarbonate ions which resulted in higher CO 2 desorption rates and cyclic capacity, but lower heat duty. However, the longer chain Alkanolamines also had high viscosities which adversely modified their performance by also introducing mass transfer limitations. Based on chain length alone, BMEA came out as the best overall alkanolamine component which could be used in a blend.
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The Development of Kinetics Model for CO2 Absorption into Tertiary Amines containing Carbonic Anhydrase
Aiche Journal, 2017Co-Authors: Zhiwu Liang, Raphael Idem, Wilfred Olson, Paitoon TontiwachwuthikulAbstract:CO2 absorption into aqueous solutions of two Tertiary Alkanolamines, namely, MDEA and DMEA with and without carbonic anhydrase (CA) was investigated with the use of the stopped-flow technique at temperatures in the range of 293–313 K, CA concentration varying from 0 to 100 g/m3 in aqueous MDEA solution with the amine concentration ranging from 0.1 to 0.5 kmol/m3, and CA concentration varying from 0 to 40 g/m3 in aqueous DMEA solution with the amine concentration ranging from 0.05 to 0.25 kmol/m3. The results show that the pseudofirst-order reaction rate (k0, amine; s−1) is significantly enhanced in the presence of CA as compared with that without CA. The enhanced values of the kinetic constant in the presence of CA has been calculated and a new kinetics model for reaction of CO2 absorption into aqueous Tertiary alkanolamine solutions catalyzed by CA has been established and used to make comparisons of experimental and calculated pseudo first-order reaction rate constant (k0, with CA) in CO2-MDEA-H2O and CO2-DMEA-H2O solutions. The AADs were 15.21 and 15.17%, respectively. The effect of pKa on the CA activities has also been studied by comparison of CA activities in different Tertiary amine solutions, namely, TEA, MDEA, DMEA, and DEEA. The pKa trend for amines were: DEEA > DMEA > MDEA > TEA. In contrast, the catalyst enhancement in amines was in the order: TEA> MDEA> DMEA> DEEA. Therefore, it can be seen that the catalyst enhancement in the amines decreased with their increasing pKa values. © 2017 American Institute of Chemical Engineers AIChE J, 2017
David Francis Myers - One of the best experts on this subject based on the ideXlab platform.
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influence of Tertiary Alkanolamines on portland cement hydration
Journal of the American Ceramic Society, 1993Co-Authors: Ellis Gartner, David Francis MyersAbstract:The physical and chemical effects of small additions of two different Tertiary Alkanolamines to portland cement were investigated. The strengths of standard test mortars moist cured for more than 1 day were found to be enhanced in some cases by addition of triisopropanolamine, but not by similar amounts of triethanolamine. Thermogravimetric and X-ray diffractometric data indicate that the increased mortar strengths resulted from an increased degree of hydration of the cement. Calorimetry and aqueous-phase analysis show that the higher alkanolamine, triisopropauo-lamine, remains in solution for a sufficient time to catalyze hydration of C4 AF after all of the free gypsum has been consumed to form calcium sulfoaluminate hydrates, In contrast, the lower alkanolamine, triethanolamine, is mostly adsorbed by the cement within the first hours of hydration. It is hypothesized that the catalytic mechanism involves facilitated transport of ferric ions through the aqueous phase in the form of ferric-alkanolamine complexes.
Jessica Narkutetteh - One of the best experts on this subject based on the ideXlab platform.
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effect of alkanol chain length of primary Alkanolamines and alkyl chain length of secondary and Tertiary Alkanolamines on their co2 capture activities
Separation and Purification Technology, 2017Co-Authors: Jessica Narkutetteh, Pailin Muchan, Raphael IdemAbstract:Abstract The effect of the alkanol chain length in primary Alkanolamines and the alkyl chain length in secondary and Tertiary Alkanolamines on CO 2 absorption and desorption kinetics, equilibrium CO 2 loading, heat duty, cyclic capacity, and pKa were studied. A selection strategy developed in our earlier work was used to identify potential solvents which could be used in a blend. Based on the strategy, Alkanolamines that had a combination of high absorption parameter and high desorption parameter should be selected. The results of this study showed that, for absorption parameters, longer alkanol chain lengths of primary Alkanolamines and longer alkyl chain lengths of secondary and Tertiary Alkanolamines led to higher equilibrium CO 2 loading and pKa. However, the influence of mass transfer limitations on these positive effects resulted in a maximum trend for initial rate of CO 2 absorption for secondary and Tertiary Alkanolamines. On the other hand, for the desorption parameters, the increase in the chain lengths also caused the generation of larger amounts of bicarbonate ions which resulted in higher CO 2 desorption rates and cyclic capacity, but lower heat duty. However, the longer chain Alkanolamines also had high viscosities which adversely modified their performance by also introducing mass transfer limitations. Based on chain length alone, BMEA came out as the best overall alkanolamine component which could be used in a blend.
Phillip K Koech - One of the best experts on this subject based on the ideXlab platform.
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assessing anhydrous Tertiary Alkanolamines for high pressure gas purifications
Industrial & Engineering Chemistry Research, 2013Co-Authors: Paul M Mathias, Louis V Jasperson, David Vonniederhausern, Mark D Bearden, Phillip K Koech, Charles J Freeman, David J HeldebrantAbstract:Anhydrous Tertiary Alkanolamines chemically react with CO2 and H2S, with greater selectivity for the latter. This is in direct contrast to aqueous amine-based solvent systems, which exhibit higher selectivity for CO2 over H2S. Anhydrous Tertiary Alkanolamines exhibit pressure-induced chemical fixation of CO2 to form zwitterionic ammonium alkylcarbonate ionic liquids, while the same Tertiary Alkanolamines react with H2S at atmospheric pressures to form hydrosulfide ionic liquids. This difference in capture pressure implies that certain anhydrous Alkanolamines could be chemically selective for H2S over CO2. We present here the first published vapor–liquid–liquid equilibrium (VLLE) data of anhydrous ethyldiethanolamine (EDEA) with CH4, C3H8, H2S, and CO2 at 10–50 °C measured by the TPx and TPxy methods. The data are modeled in Aspen Plus using an NRTL-with-solvation model. Data trends and the underlying phenomena are discussed for each gas. We also present process simulations that compare anhydrous EDEA’s pe...
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Chemically selective gas sweetening without thermal-swing regeneration
Energy and Environmental Science, 2011Co-Authors: Phillip K Koech, Mark D Bearden, James E. Rainbolt, Feng Zheng, David J HeldebrantAbstract:Natural gas purifications using chemically selective hydrogen sulfide (H2S) sorbents could be more efficient if chemical selectivity for H2S could be maintained without thermal regeneration of the sorbent. We used Tertiary Alkanolamines to reversibly capture H2S in the absence of water to produce hydrosulfide-based ionic liquids in high yield. These alkanolammonium hydrosulfide ionic liquids release H2S by exposure to inert gas or by mild heating. H2S can be rapidly and nearly quantitatively released at ambient temperature from the alkanolammonium hydrosulfide ionic liquids by the addition of nonpolar antisolvents, some of which naturally phase separate from the spent alkanolamine. The antisolvent-induced regeneration of the alkanolamine potentially allows an efficient H2S gas scrubbing process that is chemically selective and can be operated continuously at or near ambient temperature.
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anhydrous Tertiary Alkanolamines as hybrid chemical and physical co2 capture reagents with pressure swing regeneration
Energy and Environmental Science, 2011Co-Authors: James E. Rainbolt, Phillip K Koech, Feng Zheng, Clement R Yonker, Denise Main, Matt L Weaver, John C Linehan, David J HeldebrantAbstract:Anhydrous DMEA, DEEA and DIPEA are found to absorb carbon dioxide under pressure via chemical binding and physical absorption. The chemical CO2-bound derivatives of these materials are zwitterionic alkylcarbonate salts which are characterized by high-pressure 13C NMR. DMEA, DEEA and DIPEA absorb 20 wt.%, 17 wt.% and 16 wt.% carbon dioxide, respectively, at 300 psig (20.6 ATM). An increasing chemical carbon dioxide uptake capacity trend of DMEA > DEEA > DIPEA is observed while the physical CO2 absorption trend is DIPEA > DEEA > DMEA. DMEA captures up to 45 mole % (20 wt.%) of CO2 at 500 psig via both chemical binding and physical absorption. The amount of chemically bound and physically absorbed CO2 is directly linked to the CO2 pressure over the liquid. The zwitterion DMEA-CO2 regenerates CO2 and DMEA upon depressurization, allowing for an economical pressure swing regeneration rather than thermal regeneration. DMEA absorbs/releases CO2 repeatedly with no decline in capacity.