Monoethanolamine Solution Research Articles

Unraveling a novel biphasic CO2 capture process through rigorous modeling

Modification of the chemical absorbent is a crucial aspect in the field of CO2 capture. Nevertheless, the consequences arising from the utilization of modified solvents have not been thoroughly examined on a process scale. This study investigates a biphasic chemical absorption process for CO2 capture using a blended solvent composed of 2-ethylamino ethanol (EAE), diethylene glycol diethyl ether (DEGDEE), and water. The design was based on rigorous consideration of the physical properties of the pure components and the solution, as well as chemical equilibrium. Our results indicate that the proposed biphasic process reduces specific regeneration energy by 6.45 % compared to the conventional method using monoethanolamine (MEA) solution as a solvent (biphasic: 3.41 GJ/Ton; conventional: 3.63 GJ/Ton). Furthermore, it presents the advantage of utilizing low-temperature waste heat for solvent stripping, resulting in a notable 56 % decrease in indirect emissions (biphasic process: 0.119 Ton/Ton, conventional: 0.274 Ton/Ton). When processing flue gases that are more diluted in CO2, the CO2-e of the biphasic process was only slightly increased. Finally, the techno-economic analysis demonstrated that the biphasic process exhibits minimum required treatment prices (MRTPs) comparable to those of conventional methods for treating flue gases with CO2 concentrations ranging from 10 to 19 mol% (biphasic: 0.755 to 1.452 USD/kg, conventional: 0.756 to 1.455 USD/kg). This finding highlights the economic potential of the biphasic process. Overall, this investigation sheds light on the potential of intensifying the CO2 capture process in a biphasic environment.

The evolution of morphology and structure in spin-coated Zinc Acetate thin films and their impact on ZnO film morphology

The deposition of ZnO thin films using sol-gel technology is a straight forward and widely used method for fabricating ZnO films with diverse morphologies and tunable electrical and optical properties. Notably, the preparation of ZnO compact layers from a zinc acetate and monoethanolamine (ZA:MEA) solution via spin-coating has gained popularity due to its simplicity. The pretreatment of spin-coated ZA:MEA films significantly impacts the morphology and structure of the resulting ZnO films. While the effects of preheating and its rate on ZnO precursor films have been extensively studied, the morphological and structural evolution of ZA:MEA films immediately after spin-coating and its subsequent impact on the final ZnO film have not been previously explored. In this study, we present the topography and phase composition of as-grown ZA:MEA films using atomic force microscopy (AFM). We conduct an in-situ investigation of the morphological evolution of ZA:MEA films. Our results reveal that as-grown ZA:MEA films possess an inhomogeneous structure. AFM phase image shows two distinct domains in the ZA:MEA films. Over time, we observe the growth of crystals in both vertical and perpendicular directions. ZA:MEA film aged for at least 20 hours develops arrays of vertically oriented crystals throughout the film covered with sheet-like crystals forming on the film surface. This temporal evolution in the morphology and structure of ZA:MEA films significantly influences the morphology of the final ZnO film.

Pre-treatment of waste hydrated cement used for replacement of fine aggregate using amine-based CO2 solvent

In the realm of construction and demolition (C&D) waste, a small fraction of hydrated cement waste is typically repurposed to generate supplementary cementitious material or filler for concrete. However, the conventional method of utilizing it in powder form demands significant energy consumption to achieve the necessary fineness. Therefore, this study proposes a method to use a waste-hydrated cement paste as a fine aggregate as well as the pre-treatment method to enhance its properties. The pre-treatment involves carbonating hydrated cement in a fully CO2-dissolved amine-based CO2 solvent, specifically a monoethanolamine (MEA) solution. This process eliminates vulnerable phases, such as calcium hydroxide, resulting in a higher compressive strength of mortar when incorporating the treated hydrated cement as fine aggregate. Notably, the use of fully CO2-dissolved 1% and 10% MEA solutions during carbonation demonstrates superior performance and increased CO2 uptake. Additionally, the developed pre-treatment method uses MEA CO2 solvent directly, commonly utilized for CO2 capture in industrial flue gas. It is an alternative for solvent regeneration without the need for a heating process, potentially reducing overall energy consumption.

Experimental Investigation of Amine Regeneration for Carbon Capture through CO2 Mineralization

Summary The most common method for point-source carbon capture involves the absorption of CO2 from flue gas by amine solutions. The CO2 is then stripped from the amine solution by desorption with steam or heat. While amine solvents exhibit high CO2 absorption efficiency, their desorption process consumes a substantial amount of energy. A more energy-efficient alternative for the regeneration of the amine can be done through a mineralization process. Past studies have shown the feasibility of mineralizing captured CO2 from amine solution using calcium oxide (CaO) or other CaO-containing industrial waste. This study aims to show experimentally the extent of mineralization over time in near-ambient conditions and develop a mechanistic model. Lab-scale experiments are conducted to determine the absorption characteristics of CO2 in monoethanolamine (MEA) solutions and the extent of mineralization. We observe that pH serves as an indicator for CO2 loading in amine solutions. At high concentrations of MEA, CO2 absorption efficiency is about 0.5 mol CO2/mol MEA. Under ambient pressure and a temperature of 40°C, CaO effectively mineralizes CO2 and regenerates MEA. The CaO initially reacts with water to produce calcium hydroxide (Ca(OH)2) and subsequently reacts with dissolved CO2, forming calcium carbonate (CaCO3). Both 13C nuclear magnetic resonance (NMR) and FTIR indicate that MEA can be regenerated with an efficiency close to 69 to 98%, by comparing the carbamate and bicarbonate peaks in the 13C NMR response. A model to describe the absorption and mineralization reaction is proposed using the PHREEQC software; the pH is matched within less than 3% error. This study demonstrates that CO2 desorption from MEA solutions can occur through mineralization, converting CO2 into carbonates at low pressure and temperature with CaO. This method has lower energy consumption and results in the most stable form of CO2, making it a safer sequestration strategy than supercritical CO2 storage in reservoirs.

Efficient and eco-friendly carbon dioxide capture with metal phosphate catalysts in monoethanolamine solutions

Efficient and eco-friendly carbon dioxide capture with metal phosphate catalysts in monoethanolamine solutions

Investigation of carbon dioxide absorption performance in amine amino acid salts for upgrading biogas applications: Blended absorbents of piperazine and amino acid solutions

BackgroundThe increasing amount of CO2 in the atmosphere is a critical environmental issue, necessitating the development of efficient CO2 capture technologies. Amine amino acid solutions (AAAS) have demonstrated potential in improving CO2 absorption and desorption. This study explores the efficiency of various AAAS, including piperazine (PZ), glycine (Gly), lysine (Lys), sarcosine (Sar), and alanine (Ala), under specific experimental conditions. MethodologyThe CO2 absorption and desorption processes were investigated using AAAS under conditions of 45 % CO2 at 313.15 K and with pure N2 at 353.15 K, respectively. The findings obtained for CO2 loading, regeneration rate, CO2 desorption heat, and 13C nuclear magnetic resonance (NMR) are valuable for understanding their impacts on the design and improvement of energy efficiency CO2 capture techniques. Furthermore, the physicochemical properties of PZ + lysine solutions such as density, viscosity, and vapor pressure were also measured at equimolar concentration ranges such as 0.75 M, 1.0 M, 1.25 M, and 1.5 M at T = 303.15 K to 353.15 K and 0.1 MPa pressure. Significant findingsThe study revealed significant enhancements in CO2 absorption and desorption with the addition of AAAS compared to monoethanolamine (MEA) solutions. Notably, among all the solutions, the PZ + lysine solution exhibited the maximum CO2 cyclic capacity at 0.792 mol CO2/mol absorbent, and the lowest regeneration heat. These findings provide valuable insights into the design and improvement of energy-efficient CO2 capture techniques.

Photoinduced Carbon Dioxide Release via a Metastable Photoacid in a Nonaqueous Environment.

Capturing carbon dioxide (CO2) from the atmosphere is a scientific and technological challenge. CO2 can be captured by forming carbamate bonds with amines, most notably monoethanolamine (MEA). Regenerating MEA by releasing captured CO2 requires that the carbamate solution be heated. Recently, photoacids were used to induce a pH change to release CO2 from aqueous carbonate solutions. We report a merocyanine photoacid that releases CO2 from nonaqueous carbamate solutions of MEA, which has a CO2 loading capacity that is higher than that of water. On the basis of the absorption spectra of the photoacid in the presence of acids and CO2, we show that the photoacid cycle and the CO2 capture of MEA are two separate equilibria coupled to each other via protons. We demonstrate that irradiating the sample with 405 nm light induces the release of CO2, which we detect using an in-line mass spectrometer. This work highlights an alternative path for optimizing a photoinduced CO2 capture and release system.

Deep Eutectic Solvent + Water System in Carbon Dioxide Absorption.

In the present work, deep eutectic solvents (DESs) were synthesized in a one-step process by heating the hydrogen bond acceptors (HBAs) tetrabutylammonium bromide and tetrabutylphosphonium bromide, along with two hydrogen bond donors (HBDs) ethanolamine and N-methyldiethanolamine, which were mixed in certain molar ratios. This mixture was then mixed with water to form a DES + water system. The densities of the prepared DES + water systems were successfully measured using the U-tube oscillation method under atmospheric pressure over a temperature range of 293.15-363.15 K. The CO2 trapping capacity of the DES + water systems was investigated using the isovolumetric saturation technique at pressures ranging from 0.1 MPa to 1 MPa and temperatures ranging from 303.15 K to 323.15 K. A semi-empirical model was employed to fit the experimental CO2 solubility data, and the deviations between the experimental and fitted values were calculated. At a temperature of 303.15 K and a pressure of 100 kPa, the CO2 solubilities in the DES + water systems of TBAB and MEA, with molar ratios of 1:8, 1:9, and 1:10, were measured to be 0.1430 g/g, 0.1479 g/g, and 0.1540 g/g, respectively. Finally, it was concluded that the DES + water systems had a superior CO2 capture capacity compared to the 30% aqueous monoethanolamine solution commonly used in industry, indicating the potential of DES + water systems for CO2 capture.

Effect of Graphene Quantum Dots (GQDs) on the mechanical, dynamic, and durability properties of concrete

Addressing ecological concerns stemming from concrete usage is paramount, prompting exploration into additives for mitigation. Graphene quantum dots (GQDs) have been recognized for their potential to improve the mechanical attributes of cement composites. Additionally, the electrochemical reduction of a saturated solution of carbon dioxide (CO2) and monoethanolamine (CO2-MEA) effectively removes CO2 from the atmosphere. This study delves into the influence of GQDs on the mechanical and durability aspects of concrete. It is noted that the control mix of concrete without GQDs was specifically designed for concrete railway sleepers. Varied proportions of GQDs, ranging from 0.3 % to 1.2 % at 0.3 % increments, were incorporated to assess their impact on fresh and hardened concrete properties. Mechanical properties such as compressive strength, splitting tensile strength, flexural strength, and dynamic properties were evaluated. Durability assessments encompassing water absorption and chloride ion penetration were conducted. Microstructural analysis via Field Emission Scanning Electron Microscopy (FESEM) imaging and Energy-dispersive X-ray spectroscopy (EDS) elucidated the concrete's internal composition. Notably, an optimal GQDs percentage of 0.3 % was observed, signifying its efficacy in enhancing the performance of concrete. When 0.3 % of GQDs was added to concrete, compressive strength, split tensile strength, and flexural strength were enhanced by 10.8 %, 23 %, and 11 % respectively. The incorporation of GQDs resulted in a notable improvement in the fundamental frequencies and dynamic modulus of elasticity. Concurrently, a decrease in the damping ratio was observed for specimens containing GQDs. Additionally, the porosity and chloride penetration depth were lower by 6 % and 30 % for specimens with 0.3 % GQDs. The improvement in workability, mechanical, and dynamic properties of concrete, along with reducing CO2 from the atmosphere, makes GQDs an ideal eco-friendly material. This study is the first to open new pathways for the development of construction materials that are not only structurally superior but also environmentally responsible, marking a significant step forward in the field of civil engineering materials, especially in railway applications.

Effect of NOX and SOX Contaminants on Corrosion Behaviors of 304L and 316L Stainless Steels in Monoethanolamine Aqueous Amine Solutions

This work is devoted to evaluating the corrosion behaviors of SS 304L and SS 316L in monoethanolamine solutions (MEA) containing SOX and NOX pollutants, examining both lean and CO2-loaded conditions at 25 °C and 40 °C. Electrochemical techniques (potentiodynamic and cyclic polarization) were used along with Scanning Electron Microscopy, Confocal Microscopy and weight loss measurements. The results reveal that the introduction of SOX and NOX pollutants increased the corrosion rate, whereas CO2 loading primarily reduced the corrosion resistance in the lean MEA solution, while its impact on solutions with SOX and NOX was less pronounced. This suggests that SOX and NOX play primary roles in the metal’s dissolution. Also, SS 316L demonstrated superior corrosion resistance compared to 304L in nearly all of the cases examined. Elevated temperatures were also found to intensify the corrosion rate, indicating a correlation between the corrosion rate and temperature. A microscopic observation and EDX analysis revealed that corrosion products are characterized by high concentrations of iron (Fe) and oxygen (O) as well as carbon (C). There is also an indication of the possible formation of amine complexes, suggesting a potential for amine degradation. No pitting corrosion was observed in SS 304L and SS 316L across any tested solution. Finally, the immersion results expose a tendency for passivity in all amine solutions and at both temperatures after several days of exposure. Moreover, they confirm the very low corrosion rate calculated from potentiodynamic curves due to minimal weight loss after 24 days of immersion.

Performance study of activated multi-walled carbon nanotubes on catalyzing amine-based carbon capture

Organic amine solution is currently the most commonly used chemical absorbent for carbon dioxide (CO2) capture, but its drawback such as high energy consumption for regeneration of CO2 loaded solution has seriously hindered its wide application in industry. Development of catalysts could reduce the regeneration energy consumption of the process. In this study, the catalytic effects of raw multi-walled carbon nanotubes (MWCNTs) and acid-treated MWCNTs in 30 wt% monoethanolamine solution on both absorption and desorption procedures were investigated. The results showed that the addition of raw MWCNTs and acid-treated MWCNTs as catalysts both promoted the CO2 desorption rate and amount, among which the 700 ppm acid-treated MWCNTs increased the CO2 desorption amount by 48.49 %. Furthermore, both MWCNTs shortened the desorption time of CO2 as well. Stability of acid-treated MWCNTs has been examined by 20 cycles in the capture system. Characterization results indicate that the acid treatment increased the surface area of MWCNTs, and created more acid sites on their surfaces through the defected area. Both characteristics contribute to the enhanced CO2 desorption performance. Therefore, acid-treated MWCNTs can be considered as promising catalysts for promoting CO2 desorption and reducing energy consumption for CO2 capture.

Effective amine solvent regeneration over NiO-modified SBA-15 catalysts for energy-saving CO2 capture

Catalytic amine regeneration can decrease the energy required for regeneration; therefore, high economic and energy efficiency can be expected for CO2 capture. These factors necessitate the development of an inexpensive and easily synthesizable catalyst that can exhibit a high desorption efficiency. When selecting a catalyst, its physicochemical properties must be considered, because they markedly affect the chemical reaction between CO2–amine–catalyst. In this study, mesoporous silica SBA-15, particularly, rod-type SBA-15, wrinkled SBA-15 (modified from rod-type SBA-15), and NiO-impregnated rod-type and wrinkled SBA-15 catalysts were investigated in terms of the CO2 desorption rate and heat duty in a CO2–rich 5 M monoethanolamine (MEA) solution at 86 ℃. The physicochemical properties of the catalysts were compared to investigate their effect on the CO2 desorption efficiency. The performance of wrinkled SBA-15 impregnated with 10 wt% NiO in a CO2–rich MEA solution was optimal, exhibiting a 12 % higher CO2 desorption rate and 19.9 % lower heat duty than the MEA solution without a catalyst. Furthermore, the stability and reproducibility of the catalysts were confirmed through repeated experiments under identical conditions. Based on the experimental results and analysis, a plausible desorption mechanism for CO2–MEA–catalyst was proposed. It is expected that the regeneration heat duty during the CO2 regeneration can be effectively reduced by a catalyst, eventually applied to the CO2 capture.

Enhanced CO2 absorption in amine-based carbon capture aided by coconut shell-derived nitrogen-doped biochar

The sluggish CO2 absorption kinetics and constrained CO2 absorption capacity diminish the practicality of using amine-based absorption for CO2 capture, impeding progress toward carbon neutrality goals. This study aims to develop a catalytic CO2 absorption process to promote CO2 absorption by introducing a solid base catalyst, namely, coconut shell-derived nitrogen-doped biochar (NBC), into an amine-based solution. The coconut shells were modified with urea and activated with KOH to prepare an NBC catalyst with improved basic characteristics. The findings showed that compared to non-catalytic absorption, the NBC catalyst increased the CO2 absorption amount, CO2 absorption rate, and absorption efficiency of the monoethanolamine (MEA) solution by 16.9 %, 43.4 %, and 13.1 %, respectively. The basic sites on the NBC surface provided extra electrons to motivate the formation of MEACOO- and HCO3-. NBC’s large surface area and porous structure also advanced the gas–liquid mass transfer, accelerating the CO2 absorption rate. Furthermore, the NBC exhibited excellent cyclic stability and facilitated the subsequent CO2 desorption process. This work develops a promising and practical approach to significantly improve the amine-based absorption and reuse of waste biomass resources for efficient CO2 capture.

Catalytic behavior of aluminum-modified SAPO-34 catalysts for reducing the energy penalty of CO2-rich amine solutions regeneration

The goal of this research is to develop a potential strategy to significantly decrease the heat duty for the amine-based CO2 capture process. Here, a variety of Al2O3-modified SAPO-34 composite catalysts with varying Al2O3 contents are synthesized and utilized to catalytically facilitate the CO2 desorption process. The catalytic CO2 desorption characteristics of various catalysts, Al-SAPO-34, SAPO-34, and γ-Al2O3 are investigated in a CO2-loaded 5 M monoethanolamine (MEA) solution. The results indicate that all catalysts accelerate CO2 desorption, while the Al-SAPO-34 catalysts work better than the parent Al2O3 and SAPO-34 catalysts. Especially, the 15 % Al-SAPO-34 increases the CO2 desorption rate by 78.4 % and reduces the relative energy requirement by 37 % at a desorption time of 1440 s. The catalysts are characterized by different methods and their structure–activity relationship is analyzed. The increased acid sites and mesoporous surface area of the Al-SAPO-34 catalyst may be responsible for its greater catalytic activity. The intermediates of the catalytic CO2 desorption process are identified by FT-IR and NMR, and then a possible catalytic regeneration mechanism is put forward. Additionally, the cyclic stability of the Al-SAPO-34 catalyst for cyclic CO2 absorption–desorption is evaluated. This work demonstrates that the Al-SAPO-34 exhibits greater catalytic CO2 desorption performance, and outstanding stability, and has the opportunity to become an attractive industrial catalyst for the amine-based CO2 capture process.

Techno-economic analysis of AMP/PZ solvent for CO2 capture in a biomass CHP plant: towards net negative emissions

Compared to conventional monoethanolamine (MEA), alternative solvents are expected to substantially contribute to reduce the energy demand of post-combustion CO2 capture from flue gases. This study presents a comprehensive techno-economic analysis of a 27 wt% 2-amino-2-methyl-1-propanol (AMP) + 13 wt% piperazine (PZ) aqueous solution for CO2 capture, compared to a 30 wt% MEA solution. The study addresses the retrofit of a carbon capture unit to a biomass-fired combined heat and power (CHP) plant, effectively making it a bioenergy with a carbon capture and storage (BECCS) system. The treated flue gas has a flow rate of 23 tons/hour (t/h) with 11.54 vol% CO2 and a 90% capture rate is aimed for. Aspen Plus V14 was employed for process simulations. Initially, binary interaction parameters for AMP/PZ, AMP/H2O, and PZ/H2O are regressed using vapor-liquid equilibrium (VLE) data, which were retrieved from literature along with reaction kinetics. Validation of parameters from available experimental literature yields an average absolute relative deviation (AARD) of only 5.9%. Afterwards, a process simulation model is developed and validated against experimental data from a reference pilot plant, using a similar AMP/PZ blend, resulting in 5% AARD. Next, a sensitivity analysis optimizes operating conditions, including solvent rate, absorber/stripper packing heights, and stripper pressure, based on regeneration energy impact. Optimized results, compared to MEA, reveal that AMP/PZ reduces the energy consumption from 3.61 to 2.86 GJ/tCO2. The retrofitting of the capture unit onto the selected CHP plant is examined through the development of a dedicated model. Two control strategies are compared to address energy unavailability for supplying the capture unit. The analysis spans 4 months, selected to account for seasonal variations. At nominal capacity, CO2 emissions, rendered negative by biomass combustion and CO2 capture, reach a maximum of −3.4 tCO2/h compared to 0.36 tCO2/h before retrofitting. Depending on the control strategy and CHP plant operating point, the Specific Primary Energy Consumption for CO2 Avoided (SPECCA) ranges from 4.91 MJ/kgCO2 to 1.76 MJ/kgCO2. Finally, an economic comparison based on systematic methodology reveals a 7.87% reduction in capture cost favoring the AMP/PZ blend. Together, these findings highlight AMP/PZ as a highly favorable alternative solvent.

Graphene Oxide Enhanced Monoethanolamine and Ethylenediamine Nanofluids for Efficient Carbon Dioxide Uptake from Flue Gas.

The addition of nanoparticles in amine solutions to produce a stable amine-based nanofluid provides a high surface area for absorption and improves the absorption rate. In this work, nanofluids were prepared by dispersing graphene oxide (GO) in monoethanolamine (MEA) and ethylenediamine (EDA) solutions for adsorption of carbon dioxide (CO2) to further improve their absorption performance by providing more reaction sites on the GO framework. GO was synthesized using the modified Hummers method and characterized for physicochemical properties using SEM, EDS, FTIR, Raman analysis, and TGA. The FTIR spectra for the GO nanoparticles before absorption showed peaks attributed to C-C, H-C, and C-O bonding. After the absorption experiments, the FTIR spectra of GO showed peaks due to C-O-NH2, N-O-N, and N-H bonding. The BET analysis further confirmed the decrease in the surface area, pore volume, and pore diameter of the GO recovered from the nanofluids after the CO2 experiment, indicating an interaction between GO and amine molecules. The absorption process of CO2 by the nanofluid was performed in a custom-made pressure chamber whereby the CO2 gas was in direct contact with the absorption fluids. The obtained adsorption rate constant (k) for the reaction between CO2 and 30% MEA and EDA solutions was 0.113 and 0.131, respectively. Upon addition of 0.2 mg/mL GO in the base solution, k increased to 0.16854 and 0.17603 for the MEA and EDA nanofluids, respectively. The proposed mechanism involves GO nanoparticles interacting with the amine groups through the oxygen-rich groups of GO. This results in the formation of a zwitterion that readily reacts with CO2, resulting in a carbamate.

A new phase-change solvent composed of diethylenetriamine, n-butanol and water for CO2 capture

In this work, a new phase-change solvent composed of diethylenetriamine (DETA)/n-butanol/water is reported for CO2 capture. Screening of the absorption solvents, and the performance of absorption, desorption, and cyclic capacity are comprehensively investigated. The experimental results show that 30 wt% DETA/water systems exhibit excellent absorption performance. Accordingly, 30 wt% DETA/n-butanol/H2O system is used as a phase-change solvent for CO2 capture. The DETA/n-butanol/H2O mixture with mass ratio 3:4:3 shows better absorption performance compared to others of 3:1:6, 3:2:5, 3:3:4, 3:4:3, 3:5:2, and 3:6:1, and the equilibrium CO2 loading reaches up to 3.70 mol·kg−1 at 60 min, 313.15 K and 101 kPa. The 3:4:3 DETA/n-butanol/H2O system displays low heat duty with a relative heat duty of 61.4 %, and outstanding cyclic capacity (CC). CC increases by 47.6 % compared to the widely used 30 wt% aqueous monoethanolamine (MEA) solution. Finally, 13C NMR is used to determine the species before and after CO2 absorption. The mechanism of the phase transition is analyzed according to the species polarity which is estimated using Gaussian 09 W program.

Enhancing CO2 capture efficiency: Computational fluid dynamics investigation of gas-liquid vortex reactor configurations for process intensification

This study employs non-thermal Computational Fluid Dynamics (CFD) simulations to explore the efficacy of a gas–liquid vortex reactor (GLVR) for intensifying CO2 capture. The investigation concentrates on the multiphase flow and mass transfer behavior in diverse GLVR experimental units. Employing a multiphase Euler-Euler CFD model integrated with a Population Balance Model (CFD-PBM), a mass transfer model, and reaction kinetics, allows us to accurately simulate the reactive absorption of CO2 into aqueous Monoethanolamine (MEA). Experiments are conducted using a 30 wt% MEA solution for CO2 absorption, serving the purpose of model validation. This comprehensive approach enables a simulation of complex dynamics within the GLVR, emphasizing bubble breakage, coalescence, and reactive mass transfer processes. Examining bubble size distribution, pressure drop, CO2 absorption efficiency, and energy input systematically across various reactor geometries and operational conditions, our findings demonstrate that an optimized GLVR configuration significantly enhances CO2 absorption compared to the original design. Furthermore, the optimized GLVR outperforms state-of-the-art process intensification equipment in terms of CO2 absorption rate per unit reactor volume and energy efficiency.

Evaluating forward osmosis performance of MEA/MDEA absorbents for water replenishment in post-combustion carbon capture

The large-scale deployment of post-combustion carbon capture exerted additional pressure on water resources. In this work, the feasibility of forward osmosis driven by unloaded or CO2 loaded Monoethanolamine (MEA), N-Methyldiethanolamine (MDEA) and their blended absorbents for water replenishment was investigated. The results indicated that the water flux of unloaded MDEA solution increased from 12.92 LMH to 18.72 LMH at amine concentrations from 1 M to 5 M, which was much higher than that of unloaded MEA solution, owing to the huge differences of the osmotic pressure. As the MEA and the MDEA were blended, some synergistic effects may work to result in the higher osmotic pressures and the lower water fluxes of MEA-MDEA blended solutions than the summation of the individual ones, respectively. Furthermore, as the CO2 was absorbed by the MEA-MDEA blended solution, the water fluxes of the CO2 loaded solutions increased nonlinearly. Specifically, when the CO2 loading was lower than a specific critical value, the growth of the water fluxes of MEA-MDEA blended solutions with the CO2 loading gradually slowed down, caused by the increase of the solute diffusion resistivity. However, when the CO2 loading exceeded the critical value, the water fluxes of blended solutions become increasing faster with the CO2 loading, probably due to the increase of the concentration of HCO3– and MEAH+. On the other hand, there was an optimal CO2 loading value that minimized the reverse solute flux.

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.