Methyldiethanolamine Research Articles

Atomistic Modeling of Natural Gas Desulfurization Process Using Task-Specific Deep Eutectic Solvents Supported by Graphene Oxide

This study employs Density Functional Theory (DFT) calculations and traditional all-atom Molecular Dynamics (MD) simulations to reveal atomistic insights into a task-specific Deep Eutectic Solvent (DES) supported by graphene oxide with the aim of mimicking its application in the natural gas desulfurization process. The DES, composed of N,N,N′,N′-tetramthyl-1,6-hexane diamine acetate (TMHDAAc) and methyldiethanolamine (MDEA) supported by graphene oxide, demonstrates improved efficiency in removing hydrogen sulfide from methane. Optimized structure and HOMO-LUMO orbital analyses reveal the distinct spatial arrangements and interactions between hydrogen sulfide, methane, and DES components, highlighting the efficacy of the DES in facilitating the separation of hydrogen sulfide from methane through DFT calculations. The radial distribution function (RDF) and interaction energies, as determined by traditional all-atom MD simulations, provide insights into the specificity and strength of the interactions between the DES components supported by graphene oxide and hydrogen sulfide. Importantly, the stability of the DES structure supported by graphene oxide is maintained after mixing with the fuel, ensuring its robustness and suitability for prolonged desulfurization processes, as evidenced by traditional all-atom MD simulation results. These findings offer crucial insights into the molecular-level mechanisms underlying the desulfurization of natural gas, guiding the design and optimization of task-specific DESs supported by graphene oxide for sustainable and efficient natural gas purification.

Potential toxic effects linked to taurine interactions with alkanolamines and diisopropylamine

Diisopropylamine (DIPA), aminomethyl propanol (AMP), amino ethoxy ethanol (AEE), diethanolamine (DEA), ethanolamine (EA), pyridine (PYR) and methyl diethanolamine (MDEA) are used for carbon capture and to sweeten sour gas, and are found in groundwater. They are also used in cosmetic products. Taurine is abundant in the body, with key biological functions linked to its charged SO groups. Interactions between SO and amines have not been studied, but can strongly affect the biological function of taurine. Fourier transform infrared spectroscopy indicates SO…HN hydrogen bonding between taurine and DIPA, AMP, AEE, DEA, EA and MDEA. These interactions induce the formation of hydrophobic amine-taurine clusters, thus decreasing amine miscibility in water, as revealed by light scattering. This effect is most marked for DIPA, leading to turbid mixtures indicative of micron-sized droplets. PYR and taurine likely interact via S…N bonding. This study offers insights regarding potential mechanisms of amine toxicity to humans.Graphical

Development of membrane bioreactor for conversion of flue Gas-CO2 to C1 and C2 biomolecules

The capture and utilization of CO2 (CCU) from flue gases constitute a novel carbon feedstock for producing renewable chemicals and fuels. To lower the energy demand of CCU, Bio-Integrated Carbon Capture and Utilization (BICCU) was recently presented, where CO2-consuming microorganisms simultaneously desorb and convert CO2 captured from flue gas by methyl diethanolamine (MDEA) with H2 from water-electrolysis as the electron donor. The limiting factor is the microbial toxicity of MDEA, which restricts the capacity of the process. Furthermore, producing soluble molecules like the C2 platform molecule acetate is not possible without contaminating the product with capture agent. To resolve both challenges, we here propose a three-phase membrane system, where the MDEA and microorganisms are separated by a CO2-permeable membrane. Biological batch experiments with a mixed mesophilic culture confirmed the increased capacity of the BICCU-process for producing both methane and acetate when introducing a CO2-permeable membrane to the system to alleviate microbial inhibition by the capture agent and avoid contamination of soluble bioproducts. When using O2-rich flue gas from a biogas combustion engine, the CO2 conversion rate decreased by 18.0 % compared to a clean 20:80 CO2:N2 gas mixture, yet anaerobic metabolisms were still active in the mixed inoculum. Abiotic experiments furthermore showed that the microbial CO2 consumption maintained the gradient across the membrane and enhanced the CO2-flux by a factor of 3.1 ± 0.3. The membrane-based BICCU concept is expected to hold great promise particularly for producing acetate from flue gas-CO2, as the in situ separation eliminates the need for costly downstream separation.

Evaluation of antifoaming behaviour of polysiloxane mixed with fluoroalkyl as antifoam in degraded amine solution

The removal of CO2 from natural gas by absorption in amine-based solvent is a vital process for oil and gas industries. However, this process frequently struggles to meet its market specifications due to the degradation of amine solution by contaminants in the absorption system which often leads to foam formation and cause issues such as reduction in process performance. The aim of this study is to evaluate the antifoaming performance of Polymethylhydrogensiloxane (PMHS) with Hexafluorobutyl Acrylate (HFBA) antifoam in the methyldiethanolamine (MDEA) and piperazine (PZ) solution degraded by glycine, heptanoic acid and bicine. The antifoaming performance of PMHS + HFBA antifoam in this study has been found to be superior compared to the PDMS antifoam. The highest antifoaming performance for PMHS + HFBA and PDMS antifoam is in the presence of heptanoic acid with the highest average foaming tendency reduction of 61.91 % and 42.39 % respectively. This is attributed to the higher spreading coefficient of PMHS + HFBA antifoam that enables it to rupture foam at a faster rate. This study will demonstrate the importance of the continuous improvement of the use antifoams in reducing foam formation for absorption systems.

Enhancing CO2 desorption efficiency with Non-Aqueous Catalyst-Enhanced Tri-Blend amines

The substantial energy demand of CO2-loaded solvent regeneration constitutes a significant economic challenge for the industrial applications of CO2 capture and utilization technologies. The nano-catalysts have the capability to improve CO2 desorption while reducing the energy demands for solvent regeneration. This study focuses on examining the absorption–desorption performance of non-aqueous tri-blend amines (monoethanolamine (MEA), methyl diethanol amine (MDEA), and piperazine (PZ)) utilizing different amounts of catalysts including HZSM-5, H-ferrierite (FER), and H-mordenite (MOR), γ-aluminium-oxide (Al2O3), titanium-oxide (TiO2), magnesium oxide (MgO), indium-oxide (In2O3). The incorporation of solid catalysts leads to a substantial enhancement in the desorption performance of tri-blend amines and reduced energy consumption in comparison to blank tests. Higher desorption efficiency occurred with the presence of lower catalyst amounts. The sequence of CO2 desorption heat duty performance reduction with 0.125 g catalyst, was as follows: MgO (70.9 %) > In2O3 (80.2 %) > HZSM-5 (84.1 %) > Al2O3 (84.2 %) > FER (87.1 %) > MOR (88.4 %) > TiO2 (89.7 %), relative to blank test (100 %). HZSM-5 exhibited the highest desorption factor as 4.25*10-7 mol3/kJmin while increasing the desorption rate to 2.37*10-3 mol/min. This study provides the desorption performance of non-aqueous amine blends with energy-efficient catalysts, highlighting their potential as promising materials for carbon capture and storage applications with improved energy efficiency.

Improving the activity of CO2 capturing from flue gas by membrane gas – solvent absorption process

This work is focused on increasing the capturing efficiency of carbon dioxide (CO2) through flue gas purification systems. To maximize the CO2 capture process, many process variables such as temperature, flow rates, absorbent concentrations, and nanoparticles were investigated. This study describes the use of a polypropylene hollow fiber membrane contactor to separate CO2 from nitrogen using different solvents, including Potassium carbonate (K2CO3), N-methyl diethanolamine (MDEA), and monoethanolamine (MEA). Also, the presence of silica nanoparticles and piperazine (PZ) enhances the process performance. On the other hand, the amine and mixed amino absorbents MDEA-PZ and MDEA-MEA were prepared and compared based on the absorption capacity. The optimal order of amine absorbent performance when applied to CO2 membrane absorption is MDEA-MEA followed by MDEA-PZ. At a solute concentration of 9%, MDEA-MEA exhibits the highest CO2 removal efficiency, which is 74.12%. However, at a concentration of 11%, MEA, MDEA-PZ, and MDEA have the highest CO2 removal efficiencies of 80.15%, 75.13%, and 63.12%, respectively.

CO2 Removal in Hydrogen Production Plants

Hydrogen is an industrial raw material both for the production of chemicals and for oil refining with hydrotreating. It is the subject of increasing attention for its possible use as an energy carrier and as a flexible energy storage medium. Its production is generally accomplished in Steam Methane Reforming (SMR) plants, where a gaseous mixture of CO and H2, with a limited number of other species, is obtained. The process of production and purification generates relevant amounts of carbon dioxide, which needs to be removed due to downstream process requirements or to limit its emissions to the atmosphere. A work by IEAGHG focused on the study of a state-of-the-art Steam Methane Reforming plant producing 100 kNm3/h of H2 and considered chemical absorption with MethylDiEthanolAmine (MDEA) solvent for removing carbon dioxide from the PSA tail gas in a baseline scheme composed of the absorber, one flash vessel and the regeneration column. This type of process is characterized by high energy consumption, in particular at the reboiler of the regeneration column, usually operated by employing steam, and modifications to the baseline scheme can allow for a reduction of the operating costs, though with an increase in the complexity of the plant. This work analyses three configurations of the treatment section of the off gas obtained after the purification of the hydrogen stream in the Pressure Swing Adsorption unit with the aim of selecting the one which minimizes the overall costs so as to further enhance Carbon Capture and Storage in non-power industries as well.

Structure–property relationships of cationic polyurethane surfactants: Impact on surface activity and anticorrosion performance

Three cationic polyurethane surfactants (LC1–1, LC2–2, and LC2–3), each featuring different hydrophobic structures, were synthesized using isophorone diisocyanate, N-methyl diethanolamine, 1-bromohexadecane, and 1-bromobutane. The synthesized cationic polyurethane surfactants exhibited low surface tension, excellent foaming properties, and resistance to salt, attributed to steric hindrance among long-chain alkyl groups and their “multi-point anchoring” ability. The corrosion inhibition performance of polyurethane surfactants on carbon steel in 1 M HCl solution was evalutated, and LC2–2 showing a considerable corrosion inhibition efficiency of 97.0 %. This film effectively reduced/isolated contact between the corrosive solution and the steel interface. Furthermore, quantum chemical calculations corroborated the electrochemistry experiment results, affirming that the molecular structure of LC2–2 is particularly conducive to inhibiting the corrosion of carbon steel. This study explores the relationship between the molecular structure of surfactants and its impact on both surface activity and corrosion inhibition efficiency.

Synthesis of palm oil-based bio-polyol by thiol-ene reaction: Preliminary study of its potential as cationic waterborne polyurethane for coating application

Thailand has the world's third-largest planting area for oil palm. Palm oil can be chemically modified to obtain bio-polyol instead of petroleum-based polyol. In this research, a new bio-polyol based on modified palm oil (MPO) was successfully synthesized by thiol-ene click reaction using Darocur1173 as a photoinitator. The molar ratios 2-Mercaptoethanol (ME) to carbon‑carbon double bonds for MPO synthesis was studied. The kinetics of the thiol-ene click reaction was investigated by monitoring with 1H NMR technique. The chemical structure of MPO was confirmed by 1HNMR and FTIR spectroscopy. In addition, the average molecular weight (Mn) of a series of MPO was determined by GPC. The influence of N-methyl diethanolamine (NMDEA) content as an internal emulsifier on cationic waterborne polyurethane (cWPU) was investigated. The resulting cWPU based on MPO showed well-dispersed particles with a shelf life of >6 months and the zeta potential increased with increasing NMDEA content ranging from 5.6 % to 9.6 %wt. Moreover, the plywood with cWPU coatings had a shiny gloss surface, with increasing NMDEA content. The cWPU coating with NMDEA content lower than 7.6 %wt protected the plywood surface against QUV accelerated weathering for 48 h without cracking the cWPU film. The cWPU showed a high gloss value, decreased contact angle, and increased water absorption behavior. The hydrophilicity of cWPU film increased with increasing NMDEA content. Also, increasing the NMDEA content led to a higher ratio of hard segment to soft segment in the PU chain which improved the tensile strength and thermal stability. These results demonstrated an efficient synthesis procedure which offers an opportunity to use palm oil as bio-polyol to develop green cWPU that can be used as a binder in coating applications.

Impact of thermodynamics and kinetics on the carbon capture performance of the amine-based CO2 capture system

Solvent-based CO2 capture is a commonly employed post-combustion technique in processes involving absorber-stripper columns. This study focused on computer simulations with equilibrium- and rate-based modeling of CO2 capture using the amine solvents 2-amino-2-methyl-1-propanol (AMP), diethanolamine (DEA), and methyl diethanolamine (MDEA) and thermodynamic methods involving electrolyte NRTL models. The objective of this study was to understand the impacts of rate-based modeling, the type of amine, and thermodynamic methods on carbon capture. Within this study, the amine-based CO2 capture process from coal-power plant flue gas was studied using Aspen Plus modeling. Simulations were also conducted to determine the impact of thermodynamics and kinetics on the CO2 capture performance of the system. The results were analyzed on the basis of captured CO2 according to the solvents and models. The equilibrium approach was mostly invalid because of the oversimplified ideal stage assumptions through the column. The lowest carbon capture capacity was obtained with MDEA, while DEA yielded the best results. A sensitivity analysis with rate-based modeling showed the significant impact of the inlet CO2 composition. The amine-based CO2 capture process simulation included solution chemistry, electrolyte thermodynamics, rigorous transport property modeling, reaction kinetics, and rate-based multistage simulation, which could be applicable to different solvent systems.

Post-combustion carbon capture process modeling, simulation, and assessment of synergistic effect of solvents

Post-combustion carbon capture appears to be a promising solution to reduce the emission of carbon dioxide (CO2) from power plants that generate electricity using either coal or natural gas. In addition, carbon capture process efficiency, capacity, and energy consumption have become challenging against the performance of the capture process. However, synergistic effect due to solvents blend has gained attention to reduce the process energy consumption and enhance process efficiency. In this study, blends of methyldiethanolamine (MDEA) and piperazine (PZ) at different concentrations were investigated using a validated post-combustion capture process model using Aspen HYSYS. Results were compared with 30 wt% monoethanolamine (MEA) as reference case. The effective process variables are concentration of solvents, the amount of water and solvent in the makeup section, viscosity of solvent, energy consumed in different process stages, and the amount of lean solvent flow rate. These variables were studied against fixed process variables using rate-based model. The study shows that using (43 wt% MDEA/7 wt% PZ) for post-combustion carbon capture needs 2.53 MJ/kgCO2 regeneration energy for 88.5% process efficiency compared to 4.003 MJ/kgco2 for 30 wt% MEA without the need for any process modifications. In addition, it was found that solvents synergistic effect contributes to resolving the drawbacks of post-combustion capture that will enable the high utilization of the process and contribution to reduce the consequences effect of climate change. Therefore, the study will help policymakers, industries and encourage researchers towards the large-scale commissioning of blended solvent -based post-combustion capture process.

Process simulation and optimization for post-combustion CO2 capture pilot plant using high CO2 concentration flue gas as a source

This work mainly focuses on process simulation and optimization of a high-concentrated CO2 chemical absorption process using aqueous amine solutions based on both pilot plant data and process modeling. To optimize operating parameters for reducing energy consumptions, this study explores the influence of process structure and operational parameters on the product purity, capture rate, and energy consumption, which would provide theoretical and technical support for optimizing high-concentration CO2 capture. At first, the rate-based absorption/desorption models are established and well-verified by a total of 25 sets of pilot plant data, which shows high accuracy for reliable model predictions. Under an annual absorption capacity of 50 tons at a 90% capture rate and 95% product purity, the optimal case using Monoethanolamine (MEA) solution shows an increased CO2 capture rate of 12.37% and a decreased unit energy consumption of 22.5%. After flowsheet optimization, a new system of blended MEA, Methyl diethanolamine (MDEA), and 2-Amino-2-methyl-1-propanol (AMP) solution is designed to capturing high-concentrated CO2 under the same conditions. Compared with the MEA system, its specified energy consumption is reduced by 10.35% and its CO2 capture capacity increases by 11.6 tons annually.

Electrochemical Characterization of Electrodeposited Copper in Amine CO2 Capture Media.

This study explores the stability of electrodeposited copper catalysts utilized in electrochemical CO2 reduction (ECR) across various amine media. The focus is on understanding the influence of different amine types, corrosion ramifications, and the efficacy of pulse ECR methodologies. Employing a suite of electrochemical techniques including potentiodynamic polarization, linear resistance polarization, cyclic voltammetry, and chronopotentiometry, the investigation reveals useful insights. The findings show that among the tested amines, CO2-rich monoethanolamine (MEA) exhibits the highest corrosion rate. However, in most cases, the rates remain within tolerable limits for ECR operations. Primary amines, notably monoethanolamine (MEA), show enhanced compatibility with ECR processes, attributable to their resistance against carbonate salt precipitation and sustained stability over extended durations. Conversely, tertiary amines such as methyldiethanolamine (MDEA) present challenges due to the formation of carbonate salts during ECR, impeding their effective utilization. This study highlights the effectiveness of pulse ECR strategies in stabilizing ECR. A noticeable shift in cathodic potential and reduced deposit formation on the catalyst surface through periodic oxidation underscores the efficacy of such strategies. These findings offer insights for optimizing ECR in amine media, thereby providing promising pathways for advancements in CO2 emission reduction technologies.

Kinetics Study and Modeling of CO2 Capture in New Class Dual-Functionalized Ionic Liquid Blend Methyl Diethanolamine Absorbents

Kinetics Study and Modeling of CO₂ Capture in New Class Dual-Functionalized Ionic Liquid Blend Methyl Diethanolamine Absorbents

Evaluating the Effectiveness of Piperazine on Carbon Dioxide Loading in N-Methyl Diethanolamine Aqueous Solutions and Water/Oil Microemulsions

Evaluating the Effectiveness of Piperazine on Carbon Dioxide Loading in <i>N</i>-Methyl Diethanolamine Aqueous Solutions and Water/Oil Microemulsions

Modeling H2S solubility in aqueous MDEA, MEA and DEA solutions by the electrolyte SRK-CPA EOS

In this study, an electrolyte cubic plus association equation of state (e-CPA EOS) has been proposed to predict the vapor–liquid equilibrium of (H2S) in aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA). This EOS is composed of repulsive forces, short-range interactions, short-range ionic interactions, association term, long-range ionic interactions, and Born term. The Soave– Redlich– Kwong EOS is used as a non-electrolyte part. A new iterative procedure based on the Jacobi method is introduced to obtain the compositions of all species in the liquid phase. The genetic algorithm (GA) is used to find the optimal values of binary interaction coefficients between molecules and ions. Compared with experimental data, the e-CPA EOS model successfully describes the vapor–liquid equilibrium of H2S in the aqueous solutions of MEA, DEA, and MDEA. The average absolute deviations for 313 data of MEA-H2S-H2O, 156 data of DEA-H2S-H2O, and 145 data of MDEA-H2S-H2O systems were obtained as 8.20 %, 8.04 %, and 9.41 %, respectively. In addition, for some similar cases, the capability of the e-CPA EOS was compared with the Clegg–Pitzer, N-Wilson-NRF, e-NRTL, and e-CTS models. The results indicated that the e-CPA EOS has less error than the four other models.

Measurements of density and viscosity of carbon dioxide-loaded and -unloaded nano-fluids: Experimental, genetic programming and physical interpretation approaches

In the present study, the density and viscosity of the CO2-loaded and –unloaded base solution and nano-fluid were experimentally measured and investigated from an intermolecular point of view. Nano-fluids are composed of nano-particles such as Al2O3 (0.1 wt.%), Silica-2-methylimidazole, zinc salt (Si-ZIF-8) (0.02 wt.%), and super activated carbon (SAC) (0.1 wt.%) dispersed in aqueous and hybrid Methyl diethanolamine context (MDEA, 40 wt.%) +Sulfolane (SFL), 30 wt.%) +H2O) Experimental measurements were carried out at the low-temperature ranges 303.15–315.15 K, atmospheric pressure, and three different CO2 loadings. The results show that nanomaterials do not have a significant effect on the density and viscosity of the unloaded suspension; however, the density and viscosity of loaded suspensions and base solvent become more by increasing CO2 concentration. In the case of CO2-loaded fluids, the comparison of the results in the presence and absence of nanoparticles shows that the density of the solution is not much different in the two cases, but the viscosity of CO2-loaded in Si-ZIF-8, SAC, and γ-Al2O3 base nano-fluids in comparison with base solvent shows an increase of 35 % in high CO2 loading, ∼0.3 mol CO2 per mol MDEA. Density and viscosity experimental data were modeled using the Genetic Programming approach. The highest values of absolute average relative deviation (AARD) and root mean square error (RMSE) parameters obtained for modeling data are 3.04 and 0.317, respectively, and the lowest value of regression coefficient (R2) is 0.995, which indicates the appropriate fitting of the results.

Response Surface Optimization of Nonaqueous Hexanol‐Based Trisolvent Amine Blends for Energy‐Efficient CO2 Desorption

The CO2 absorption–desorption performances of nonaqueous trisolvent blended amines, monoethanolamine (MEA), 2‐amino‐2‐methyl‐1‐propanol (AMP), methyl diethanol amine (MDEA), 1‐dimethyl amino‐2‐propanol (1DMA2P), diethyl ethanol amine (DEEA), and piperazine (PZ), are investigated in terms of desorption parameters. Two trisolvent amine combinations, primary amine (MEA)/sterically hindered amine (AMP) and tertiary amine (MDEA/1DMA2P/DEEA)‐polyamine (PZ), are prepared at 5 m total amine concentrations with different molarities. Response surface methodology based on a central composite design is used to obtain the optimal condition. This study aims to determine the molarity ratios of solvent systems and investigate their effects on objective functions: heat duty, desorption rate, and desorption factor. Surface analysis suggests optimum conditions as 3 m MEA–1.375 m MDEA–0.625 m PZ for the lowest energy consumption. The experimental results of the proposed system are compared with the 5 m MEA solution. The extensive energy penalty of the CO2 desorption of amine absorbents is reduced with the newly developed solution.

Corrosion Investigation of Carbon Steel in Different Amine-Based CO2 Removal System

The steel industry is a major source of CO2 emissions, which is affecting the corrosion behavior of carbon steel. The corrosion behavior of carbon steel (C1018) absorbed for CO2 removal is examined in different blends of amine solution by adding a heat-stable salt neutralizer and increasing amine concentration. Corrosion of carbon steel using different methyldiethanolamine (MDEA)/ (5% piperazine amine solution) which had 26% amine solution that contained heat stable amine salts treated with neutralizer at 80 °C and CO2 loading was investigated. The effect of the treated solutions on the corrosion behavior was observed using either the K2CO3 treatment solution to reach 30% amine or increasing the concentration to 33% amine solution using weight loss, potentiodynamic polarization, cyclic voltammetry, and impedance measurements. A visual examination of the corroded samples of the different amine solutions was performed. XRD for phase identification and SEM for microstructure examination were used to describe the corroded surfaces and analyze the corrosion products on the specimen surfaces under different conditions. After nine days in the 30% amine solution, these analyses showed the formation of the FeCO3 protective layer. The carbon steel in 30% amine solution provides better protection, and the lowest corrosion resistance (39.9 µm/Y).

Reviving the absorbent chemistry of electrochemically mediated amine regeneration for improved point source carbon capture

Electrochemically mediated amine regeneration (EMAR) is emerging as a promising electrochemical approach for carbon capture from point sources. In this study, for the first time, the absorbent chemistry of the EMAR process was revived by considering criteria beyond metal-amine complexation. The systematic investigation focused on using second amines, which were previously overlooked in EMAR due to limited metal-amine interaction, despite their proven effectiveness in conventional carbon capture processes. The integration of second amines— monoethanolamine (MEA), aminomethyl propanol (AMP), and methyldiethanolamine (MDEA)—with the benchmark ethylenediamine (EDA) was thoroughly studied, evaluating their impact on absorption and desorption kinetics and capacities, and electrochemical performance. Among the blends, EDA + MDEA emerged as the top performer, particularly excelling in electrochemical aspects. The charge transfer resistance (RCT) of the deposition reaction, as the rate-limiting step, for the EDA + MDEA blend was reduced by 40 % compared to pure EDA, and the heterogeneous electron transfer rate constant (k0) improved threefold. In the bench-scale assessments, the EDA + MDEA blend showed a notable decrease in desorption energetics to 37 kJ/molCO2, marking a 34 % reduction compared to the 56 kJ/molCO2 required for pure EDA. This marks the lowest reported energetics for an EMAR process targeting point source carbon capture. This research paves the way for future systematic investigations of a wider range of amine blends for EMAR and eventually the process implementation at larger scales.