Search Results (11)

The increasing atmospheric concentration of carbon dioxide (CO₂) poses a critical threat to global climate stability, highlighting the need for efficient carbon capture technologies. While amine-based solvents such as monoethanolamine (MEA) are widely used for industrial CO₂ capture, they are subject to limitations such as high energy requirements for regeneration, solvent degradation, and environmental concerns. This study investigates potassium carbonate/bicarbonate system as an alternative solution for CO₂ absorption. The absorption mechanism and reaction kinetics of potassium carbonate in the presence of bicarbonates were reviewed. A rate-based model was developed in Aspen Plus, using literature kinetics, to simulate CO₂ absorption using 20 wt% potassium carbonate (K₂CO₃) solution with 10% carbonate-to-bicarbonate conversion under different industrial conditions. Three flue gas compositions were evaluated: cement industry, biomass combustion, and anaerobic digestion, each at 3000 m³/h flow rate. The simulation was conducted to determine minimum column height and solvent loading requirements with a target output of 90% CO₂ removal from the gas streams. Results demonstrated that potassium carbonate systems successfully achieved the target removal efficiency across all scenarios. Column heights ranged from 18 to 25 m, with molar K₂CO₃/CO₂ ratios between 1.41 and 4.00. The biomass combustion scenario proved most favorable due to lower CO₂ concentration and effective heat integration. While requiring higher column heights (18–25 m) compared to MEA systems (6–12 m) and greater solvent mass flow rates, potassium carbonate demonstrated technical feasibility for CO₂ capture. The findings of this study provide a foundation for technoeconomic evaluation of potassium carbonate systems versus amine-based technologies for industrial carbon capture applications. Full article

Conventional amine-based solvents such as monoethanolamine (MEA) and diethanolamine (DEA) are widely used for CO₂ removal from natural gas but this technology suffers from drawbacks including high regeneration energy, solvent degradation, and corrosion issues. To overcome these limitations, this study investigates the use of newly synthesized hydrophobic protic ionic liquids (HPILs) composed of ammonium cations coupled with the bis(trifluoromethane)sulfonylimide ([Tf₂N]⁻) anion for CO₂ absorption using the pressure-drop method. The results show that CO₂ solubility increases with pressure but decreases with temperature. Among the studied ionic liquids (ILs), [BEHA][Tf₂N] exhibits the highest CO₂ capacity at 298.15 K within the pressure range of 1–20 bar, which is consistent with its free volume (V_f) value. Furthermore, a comparison study indicates that all ILs demonstrate superior CO₂ selectivity over methane (CH₄) at 298.15 K. The recyclability study shows that [BEHA][Tf₂N] maintains its structural integrity over two CO₂ absorption cycles at 20 bar across all tested temperatures. Full article

Aminoacetaldehyde (glycinal, NH₂CH₂CHO) is a first-generation oxidation product of monoethanolamine (MEA, NH₂CH₂CH₂OH), a solvent widely used for CO₂ gas separation, which is proposed as the basis for a range of carbon capture technologies. A complete oxidation mechanism for MEA is required to understand the atmospheric transformation of carbon capture plant emissions, as well as the degradation of this solvent during its use and the oxidative destruction of waste solvent. In this study, we have investigated the ^•OH radical-initiated oxidation chemistry of aminoacetaldehyde using quantum chemical calculations and RRKM theory/master equation kinetic modeling. This work predicts that aminoacetaldehyde has a tropospheric lifetime of around 6 h and that the reaction predominantly produces the NH₂CH₂C^•O radical intermediate at room temperature, along with minor contributions from NH₂^•CHCHO and ^•NHCH₂CHO. The dominant radical intermediate NH₂CH₂C^•O is predicted to promptly dissociate to NH₂^•CH₂ and CO, where NH₂^•CH₂ is known to react with O₂ under tropospheric conditions to form the imine NH = CH₂ + HO₂. The NH₂^•CHCHO radical experiences captodative stabilization and is found to form a weakly bound peroxyl radical upon reaction with O₂. Instead, the major oxidation product of NH₂^•CHCHO and the aminyl radical ^•NHCH₂CHO is the imine NH = CHCHO (+HO₂). In the atmosphere, the dominant fate of imine compounds is thought to be hydrolysis, where NH = CH₂ will form ammonia and formaldehyde, and NH = CHCHO will produce ammonia and glyoxal. Efficient conversion of the dominant first-generation oxidation products of MEA to ammonia is consistent with field observations and supports the important role of imine intermediates in MEA oxidation. Full article

Alternative solvents based on aqueous solutions of amino acids have been recently developed as possible substitutes for Mono Ethanol Amine (MEA) for CO₂ removal from flue gas streams. The potassium taurate solvent has the advantages of degradation resistance, low toxicity and low energy requirements for its regeneration. With any type of solvent, CO₂ removal applied to a power production plant decreases the revenues obtained from selling electricity because of the energy requirements. Operating the CO₂ removal section in flexible mode avoids significant effects on the profits of the power plant, while accomplishing environmental regulations. This work is the first journal paper focusing on the application in flexible mode of the potassium taurate system for treating a flue gas stream from a 500 MW coal-fired power plant. Techno-economic evaluations are performed to determine the best operating conditions considering the variation in the electricity demand and its price, and different values of carbon tax. In the summer period, with high electricity prices and demands, carbon tax values between 45 EUR/t_CO2 and 60 EUR/t_CO2 favor CO₂ absorption in the flexible mode, without periods of full CO₂ emissions during the day. Full article

The present study aimed to investigate the feasibility of blended amine absorbents in improving the CO₂ alkanolamine-based absorption of multicycle integrated absorption–mineralization (multicycle IAM) under standard operating conditions (20–25 °C and 1 atm). Multicycle IAM is a promising approach that transforms CO₂ emissions into valuable products such as carbonates using amine solvents and waste brine. Previously, the use of monoethanolamine (MEA) as an absorbent had limitations in terms of CO₂ conversion and absorbent degradation, which led to the exploration of blended alkanolamine absorbents, such as diethanolamine, triethanolamine, and aminomethyl propanol (AMP) combined with MEA. The blended absorbent was evaluated in terms of the absorption performance and carbonate production in continuous cycles of absorption, precipitation/regeneration, and preparation. The results showed that the fourth cycle of the blend of 15 wt.% AMP and 5 wt.% MEA achieved high CO₂ absorption and conversion efficiency, with approximately 87% of the absorbed CO₂ being converted into precipitated carbonates in 43 min and a slight degradation efficiency of approximately 45%. This blended absorbent can improve the efficiency of capturing and converting CO₂ when compared to the use of a single MEA, which is one of the alternative options for the development of CO₂ capture and utilization in the future. Full article

In most carbon dioxide (CO₂) capture processes, chemical absorption using an amine solvent is widely used technology; however, the solvent is prone to solvent degradation and solvent loss which leads to the formation of corrosion. This paper investigates the adsorption performance of amine-infused hydrogels (AIFHs) to increase carbon dioxide (CO₂) capture by leveraging the potency of amine absorption and adsorption properties of class F fly ash (FA). The solution polymerization method was used to synthesize the FA-grafted acrylic acid/acrylamide hydrogel (FA-AAc/AAm), which was then immersed in monoethanolamine (MEA) to form amine infused hydrogels (AIHs). The prepared FA-AAc/AAm showed dense matrices morphology with no obvious pore at the dry state but capable of capturing up to 0.71 mol/g CO₂ at 0.5 wt% FA content, 2 bar pressure, 30 °C reaction temperature, 60 L/min flow rate, and 30 wt% MEA contents. Cumulative adsorption capacity was calculated and Pseudo-first order kinetic model was used to investigate the CO₂ adsorption kinetic at different parameters. Remarkably, this FA-AAc/AAm hydrogel is also capable of absorbing liquid activator that was 1000% more than its original weight. FA-AAc/AAm can be used as an alternative AIHs that employ FA waste to capture CO₂ and minimize the GHG impact on the environment. Full article

Degradation occurs in catalyst inks because of the catalytic oxidation of the solvent. Identification of the generation process of impurities and their effects on the properties of HSC ink and LSC ink is crucial in mitigating them. In this study, gas chromatography-mass spectrometry (GC-MS) and cyclic voltammetry (CV) showed that oxidation of NPA and EA was the primary cause of impurities such as acetic acid, aldehyde, propionic acid, propanal, 1,1-dipropoxypropane, and propyl propionate. After the degassing treatment, the degradation of the HSC ink was suppressed, and the concentrations of acetic acid, propionic acid, and propyl propionate plummeted from 0.0898 wt.%, 0.00224 wt.%, and 0.00046 wt.% to 0.0025 wt.%, 0.0126 wt.%, and 0.0003 wt.%, respectively. The smaller particle size and higher zeta potential in the degassed HSC ink indicated the higher utilization of Pt, thus leading to optimized mass transfer in the catalyst layer (CL) during working conditions. The electrochemical performance test result shows that the MEA fabricated from the degassed HSC ink had a peak power density of 0.84 W cm⁻², which was 0.21 W cm⁻² higher than that fabricated from the normal HSC ink. However, the introduction of propionic acid in the LSC ink caused the Marangoni flux to inhibit the coffee ring effect and promote the uniform deposition of the catalyst. The RDE tests indicated that the electrode deposited from the LSC ink with propionic acid possessed a mass activity of 84.4 mA∙mg_Pt⁻¹, which was higher than the 60.5 mA∙mg_Pt⁻¹ of the electrode deposited from the normal LSC ink. Full article

Environmental concern for our planet has changed significantly over time due to climate change, caused by an increasing population and the subsequent demand for electricity, and thus increased power generation. Considering that natural gas is regarded as a promising fuel for such a purpose, the need to integrate carbon capture technologies in such plants is becoming a necessity, if gas power plants are to be aligned with the reduction of CO₂ in the atmosphere, through understanding the capturing efficacy of different absorbents under different operating conditions. Therefore, this study provided for the first time the comparison of available absorbents in relation to amine solvents (MEA, DEA, and DEA) CO₂ removal efficiency, cost, and recirculation rate to achieve Climate change action through caron capture without causing absorbent disintegration. The study analyzed Flue under different amine-based solvent solutions (monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA)), in order to compare their potential for CO₂ reduction under different operating conditions and costs. This was simulated using ProMax 5.0 software modeled as a simple absorber tower to absorb CO₂ from flue gas. Furthermore, MEA, DEA, and MDEA adsorbents were used with a temperature of 38 °C and their concentration varied from 10 to 15%. Circulation rates of 200–300 m³/h were used for each concentration and solvent. The findings deduced that MEA is a promising solvent compared to DEA and MDEA in terms of the highest CO₂ captured; however, it is limited at the top outlet for clean flue gas, which contained 3.6295% of CO₂ and less than half a percent of DEA and MDEA, but this can be addressed either by increasing the concentration to 15% or increasing the MEA circulation rate to 300 m³/h. Full article

Heat stable salts (HSS) formed and continuously accumulated in the amine-based solvents due to solvent degradation and impurities in the feed gas can dramatically change the efficiency of the amine scrubbing process. HSS can be removed by using different methods including membrane separation such as electrodialysis (ED). In this work, we studied the effect of CO₂ loading of the lean 30 wt % monoethanolamine (MEA) solution on the efficiency of HSS removal and MEA loss. In the model MEA solution containing HSS on the level of 48 meq/L, the carbon dioxide concentration was varied from 0.2 down to 0 mole (CO₂)/mole (MEA). The reclaiming of model MEA solution was carried out by lab-scale two-stage ED unit when the concentrate stream after the first stage was additionally treated using ED (second stage) that allowed reducing MEA loss. It was shown that the decrease of carbon dioxide content from 0.2 down to 0 mole (CO₂)/mole (MEA) resulted in a substantial reduction of both parameters—the MEA loss and the specific power consumption with respect to extracted HSS (from 140 down 37 kJ per 1 g of recovered HSS anions). This can be explained by the drop in the total concentration of ions formed by the interaction of MEA solution with carbon dioxide. However, the change of CO₂ loading is associated with additional power consumption towards further solvent regeneration in the column. Based on the preliminary estimations of power consumption required for additional CO₂ stripping with the respect to the power consumption of ED stage, it seems that lean solvent CO₂ loading of 0.1 mole/mole provides an optimum for the power input at 25.9 MJ/kg(solvent). Full article

The correct conduction of the CO₂ capture process in coal-fired power plants with the use of monoethanolamine (MEA) requires constant process parameter monitoring and ensuring a specific flue gas chemical composition. One of the most common problems in these types of installations is the progressive corrosion and degradation of the valuable solvent. Despite the established reduction levels of oxygen and impurities entering into irreversible reactions with the absorber, the flue gas composition may change as a daily and annual function of time. The article presents a detailed analysis of the flue gas components that have the greatest influence on carbon dioxide capture installation technical safety, i.e., SO_x, NO_x, O₂, and fly ash. The analysis was based on the results of experiments conducted at the Jaworzno III Tauron Wytwarzanie SA Polish coal power plant. The results show a significant influence of the flue gas desulfurization (FGD) process on MEA oxidative degradation. The amount of oxygen in flue gas during biomass and coal blend co-firing was nearly twice as low compared to pure coal combustion. Differences were also observed in the amounts of gas impurities with relation to the time of year and time of day of power plant operation. Full article

Oxidative degradation is a serious concern for upscaling of amine-based carbon capture technology. Different kinetic models have been proposed based on laboratory experiments, however the kinetic parameters included are limited to those relevant for a lab-scale system and not a capture plant. Besides, most of the models fail to recognize the catalytic effect of metals. The objective of this work is to develop a representative kinetic model based on an apparent auto-catalytic reaction mechanism between solvent degradation, corrosion and ammonia emissions. Measurements from four different pilot plants: (i) EnBW’s plant at Heilbronn, Germany (ii) TNO’s plant at Maasvlakte, The Netherlands; (iii) CSIRO’s plants at Loy Yang and Tarong, Australia and (iv) DONG Energy’s plant at Esbjerg, Denmark are utilized to propose a degradation kinetic model for 30 wt % ethanolamine (MEA) as the capture solvent. The kinetic parameters of the model were regressed based on the pilot plant campaign at EnBW. The kinetic model was validated by comparing it with the measurements at the remaining pilot campaigns. The model predicted the trends of ammonia emissions and metal concentration within the same order of magnitude. This study provides a methodology to establish a quantitative approach for predicting the onset of unacceptable degradation levels which can be further used to devise counter-measure strategies such as reclaiming and metal removal. Full article