Monoethanolamine Solution Research Articles

Effect of capillary pressure on the CO2 flux in the pores of membrane contactor: Theory and simulation results

A simulation model was made to evaluate the effect of the capillary pressure on the CO2 capture by membrane absorption. More specifically, the model calculated the changes in the interfacial pressure and CO2 flux as the interface of gas and liquid moves through the pore opening to its exit. Two cases were considered; hydrophilic or hydrophobic membrane materials with a respective contact angle of less or more than 90°. It was revealed that CO2 flux is about 70% higher for the hydrophilic membrane of 10−6 m radius and 50 × 10−6 m length than the hydrophobic membrane of equal pore radius and pore length, when nearly equal to 1.72 × 105 Pa is applied either on the feed side (hydrophilic membrane) or on the permeate side (hydrophobic membrane) to keep the membrane pore dry without gas bubble formation. It should be noted that CO2 flux is higher when a hydrophilic membrane is used, which is against the common belief that a hydrophobic membrane is preferable for membrane absorption. Also, the duration for the interface to get to the pore exit was determined. The effect of capillary pressure increases as the membrane pores become smaller, which turns into an increase in CO2 flux when the porosity and the pore length are maintained constant. It was also revealed that the CO2 flux can be significantly increased when water absorbent is replaced by 1 M monoethanolamine solution due to increased CO2 solubility. Thus, this work is the first attempt to study the effect of capillary pressure on the flux of membrane contactors. It is recommended to collect more data on membrane contactors by the hydrophilic membrane. Electronic structure calculations were also performed to investigate the reaction mechanism between CO2 and MEA, with a focus on non-conventional interactions such as hydrogen bonding and van der Waals interactions. This is to know the details of the reaction occurring between CO2 and MEA.

CO2 and H2S Absorption in Tofu Liquid Waste Biogas using Packed Bed Scrubber with Variation of MEA Concentration and Flow Rate

Biogas technology has become an alternative fuel that is often used in Indonesia. One of the raw materials for biogas that has the potential and is easy to obtain is waste from the tofu industry. Liquid waste still contains a lot of organic elements. The organic materials contained in the exhaust of the tofu industry are generally very high. The gases commonly found in tofu waste are nitrogen gas (N2), oxygen (O2), hydrogen sulfide (H2S), ammonia (NH3), carbon dioxide (CO2) and methane (CH4). These gases come from the decomposition of organic materials contained in wastewater. So that biogas produced from tofu liquid waste still contains CO2 and H2S gases which are quite high. Therefore, in this study the process of purification or refining of biogas products will be carried out using the absorption method through an absorber column using monoethanolamine (MEA) solution as a chemical absorbent through a 8 mm packed bed scrubber. The results showed that the best biogas flow rate in the purification process which produced the highest CH4 concentration of 95.12% was 40% MEA concentration and 0.8 L/min flow rate. The effect of MEA concentration on biogas purification causes the concentration of CO2 and H2S in the purified biogas to decrease as the MEA concentration increases. The best combination of 0.8 L/min biogas flow rate and 10 mm packing area reduces CO2 and H2S concentrations to 1.88% and 0 ppm.

Nanofluidic osmotic power generation from CO2 with cellulose membranes

The diffusion of chemical species down concentration gradient is a ubiquitous phenomenon that releases Gibbs free energy. Nanofluidic materials have shown great promise in harvesting the energy from ionic diffusion via the reverse electrodialysis process. In principle, any chemicals that can be converted to ions can be used for nanofluidic power generation. In this work, we demonstrate the power generation from the diffusion of CO2 into air using nanofluidic cellulose membranes. By dissolving CO2 in water, a power density of 87 mW/m2 can be achieved. Using monoethanolamine solutions to dissolve CO2, the power density can be increased to 2.6 W/m2. We further demonstrate that the waste heat released in industrial and carbon capture processes, can be simultaneously harvested with our nanofluidic membranes, increasing the power density up to 16 W/m2 under a temperature difference of 30 °C. Therefore, our work should expand the application scope of nanofluidic osmotic power generation and contribute to carbon utilization and capture technologies.

Process simulation and multi-aspect analysis of methanol production through blast furnace gas and landfill gas

This paper presents a novel process for methanol production from blast furnace gas (BFG) and landfill gas (LFG). The process is evaluated using the energy, exergy, economic, and environmental (4E) analyses. The process consists of a power plant fueled by LFG, carbon dioxide (CO2) chemisorption using 30% (wt.) solution of monoethanolamine, methanol synthesis and separation, and power and steam plants. Thermodynamic analysis shows that the total energy and exergy efficiencies for the proposed process are 59% and 63.2%, respectively. The carbon efficiency for this method is 42%. Environmental analysis shows that the total CO2 emission is 2614.85 kg/h. Based on the simulation results, this process produces 18,200 kg/h methanol, which results in a CO2 emission intensity of 0.144 kg CO2/kg MeOH. Economic evaluation determines that the proposed scheme has a capital cost of $100, 315, 128.9 with a payback period of 1.94 years. In addition, methanol production's annual profit is $4,798,088.309, and the minimum selling price of the produced methanol is $0.388/kg. The proposed process is a promising alternative for methanol production from BFG and LFG. It has high energy and exergy efficiencies, low CO2 emission intensity, and a short payback period. The economic analysis shows that the process is profitable.

Kinetics of novel non-corrosive amino functionalized ionic liquid organic solution for CO2 capture

Extensive energy consumption is a challenge for developing industrial carbon capture absorbents. A novel amino functionalized ionic liquid (AFIL) organic solution, tetraethylene pentamine 5-amino-4-imidazolecarboxamide/n-propanol/ethylene glycol ([TEPAH][AICA]/NPA/EG), is considered as a promising absorbent due to its high CO2 absorption capacity and low energy consumption. However, its industry application potential still needs to be further evaluated for carbon capture process. In this work, thermodynamics, kinetics and corrosive behavior of [TEPAH][AICA]/NPA/EG solution were investigated. The regeneration energy consumption was 2.30 GJ⋅t−1 CO2, which was 39.5% lower than the benchmark monoethanolamine (MEA) solution. The mass transfer reaction kinetic model was established, showing that the reaction between CO2 and [TEPAH][AICA]/NPA/EG solution followed fast pseudo-first-order. The enhancement factor and reaction rate constant increased with the increase of absorption temperature, while they showed a decreasing trend with the increase of absorption loading. The relationship between the second-order rate constant and temperature was expressed as k2=7.2075×108exp-3093.5T. The activation energy was 25.72 kJ·mol−1. During absorption process, the dominant mass transfer resistance gradually changed from gas phase to liquid phase. In addition, the absorbent presented non-corrosive behavior after saturated absorption, which was superior than the MEA absorbent for storage and transportation in the carbon capture technology. To be concluded, the above results showed that the [TEPAH][AICA]/NPA/EG solution owned great potential for future industrial application.

Saturation of the MEA solution with CO2: Absorption prototype and experimental technique

The carbon dioxide (CO2) emissions from thermoelectric power plants contribute to global warming. The Monoethanolamine (MEA) solution is the most widely used solvent for CO2 removal processes from these power plants with the disadvantage that it is expensive and corrosive at high concentrations. In this work, an experimental methodology is developed to fix the operating flow ratio (L/G) that ensures the maximum absorption capacity of MEA solution. The absorption system prototype and the experimental saturation technique are detailed. The main parameters of the experimental technique were the amount (0.65 and 1.30 kg) and concentrations (10,15, 20, 25, and 30 wt%) of MEA solution with CO2 inlet gas concentration (12.5 vol%). The experimental technique shows that MEA saturation occurs when the maximum temperature increase in the solution. Continuous tests were developed to operate the absorption system with the maximum absorption capacity of the MEA solution. The results show that the temperature increases in the MEA solution are a function of the flow rates (L/G) and the MEA concentration. Furthermore, the density, viscosity, and refractive index of CO2-free and CO2-saturated MEA solution at concentrations of MEA below 30 wt% are also measured in this work.

Deep Eutectic Solvents: Properties and Applications in CO2 Separation.

Nowadays, many researchers are focused on finding a solution to the problem of global warming. Carbon dioxide is considered to be responsible for the "greenhouse" effect. The largest global emission of industrial CO2 comes from fossil fuel combustion, which makes power plants the perfect point source targets for immediate CO2 emission reductions. A state-of-the-art method for capturing carbon dioxide is chemical absorption using an aqueous solution of alkanolamines, most frequently a 30% wt. solution of monoethanolamine (MEA). Unfortunately, the usage of alkanolamines has a number of drawbacks, such as the corrosive nature of the reaction environment, the loss of the solvent due to its volatility, and a high energy demand at the regeneration step. These problems have driven the search for alternatives to that method, and deep eutectic solvents (DESs) might be a very good substitute. Many types of DESs have thus far been investigated for efficient CO2 capture, and various hydrogen bond donors and acceptors have been used. Deep eutectic solvents that are capable of absorbing carbon dioxide physically and chemically have been reported. Strategies for further CO2 absorption improvement, such as the addition of water, other co-solvents, or metal salts, have been proposed. Within this review, the physical properties of DESs are presented, and their effects on CO2 absorption capacity are discussed in conjunction with the types of HBAs and HBDs and their molar ratios. The practical issues of using DESs for CO2 separation are also described.

A new enhanced carbonation curing method using monoethanolamine (MEA) solution: Their effects on hydration and microstructure of cement-based materials

CO2 curing can improve the properties of cement-based materials and absorb the CO2, which is an effective method for pre-cast concrete. However, the application of CO2 curing is limited for the on-site concrete because the CO2 is hard to diffuse into inner fresh concrete. A new enhanced carbonation curing method has been proposed by using monoethanolamine (MEA) solution in this study. In addition, the effect of new carbonation curing on the compressive strength, hydration and microstructure has been studied. The results showed that the MEA solution can delay the hydration of cement which affects the pore structure and reduce the compressive strength. The effect of CO2-rich MEA solution on the compressive strength of cement paste is quite different from that of MEA solution. The inhibition effect of CO2-rich MEA solution that absorbs carbon dioxide on the early hydration of cement is weak, and the promotion effect on the later hydration is more obvious. The CO2-rich MEA solution can chemically react with the calcium ions in the cement slurry pore solution to generate calcium carbonate, and the small amount of calcium carbonate generated can promote the later hydration of cement.

Novel nonaqueous solvent for carbon capture: Effects of glycol and water on CO2 absorption, desorption and energy penalty

Amidine-alcohol solution is an efficient absorbent for CO2 capture with high CO2 loading and low regeneration temperature compared with 30 wt% monoethanolamine (MEA) solution. However, the high viscosity restricts its further utilization in the industry. To decrease the viscosity of amidine-alcohol solutions during the absorption of CO2, different glycols including ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,3-butanediol and 1,4-butanediol were adopted in 1,5-diazabicyclo [4,3,0] non-5-ene (DBN)-glycol solutions for CO2 absorption. Both the absorption and desorption performances of those absorbents in the reaction with CO2 were investigated including the viscosity and regeneration energy. The CO2 loading can reach as high as 5.87 mol·kg−1 in DBN-1,3-propanediol solution, which is more than 3 times higher than that of 30 wt% MEA. Meanwhile, the viscosities for DBN-glycol-CO2 systems can be decreased more than 95% compared with 1,8-diazabicyclo [5,4,0] undec-7-ene (DBU)-glycerol-CO2 system. And DBN-ethylene glycol-CO2 system shows the lowest viscosity among the five glycols systems. With DBN-1,4-butanediol solution as an absorbent, the regeneration energy can be decreased as low as 1.38 GJ·ton−1 CO2, which is 62% lower than that of 30 wt% MEA. After 9 cycles of absorption–desorption process, the CO2 loading can be kept about 72% of the initial loading. Furthermore, the effect of water on absorption, desorption, viscosity and regeneration energy was also studied. It shows that the presence of water can increase the absorption rate and has little effect on the final CO2 loading while decreasing the desorption rate. Meanwhile, the presence of water increases the regeneration energy of DBN-ethylene glycol-H2O-CO2 system. However, considering the regeneration energy and viscosity, DBN-ethylene glycol solution is a promising solution for carbon capture and the regeneration energy can be decreased about 51 % even with 5 wt% water compared with 30 wt% MEA.

Mass transfer enhancement for CO2 chemical absorption in a spiral baffle embedded microchannel

This paper presents an experimental study on CO2 chemical absorption by Monoethanolamine (MEA) solution in microchannel. In particular, a novel spirally distributed baffle structure is proposed to be embedded into the microchannel so as to generate the swirling flow pattern and to enhance the mass transfer. The effect of spiral baffle structure on the two phase flow pattern transition, the CO2 gas void fraction, the pressure drop, and the mass transfer performance are characterized and discussed, under varied gas and liquid flow rates, and MEA concentrations. Results demonstrate that the spiral baffle structure could significantly enhance the gas–liquid mass transfer, with overall liquid side volumetric mass transfer rate (kLa) up to 2.35 s−1 and enhancement number E up to 1.387 at small gas and liquid Reynolds numbers (ReG < 5.5; ReL < 14). New predictive correlations have also been proposed by considering both the structure enhancement factor and the chemical reaction factor.

Synthesis, crystal structure and Hirshfeld surface analysis of binuclear Cu(II) complexes from o/p-hydroxybenzoic acid with ethanol and water solution of monoethanolamine

The new paddlewheel-like binuclear copper complexes of general formulae [Cu2(o-HBA)4(DMFA)2] (1),[Cu2(o-HBA)4(H2O)2]DMFA (2) and {[Cu2(o-HBA)2(p-HBA)2(H2O)2]EtOH}{[Cu2(o-HBA)4(H2O)2]}, (3) (o/p-HBA = ortho/para-hydroxybenzoic acid, DMFA = Di-methylforamide) have been obtained by the reaction in ethanol, water and water: ethanol solution of MEA (monoethanolamine) and freshly prepared copper hydroxide with o-HBA (for 1 & 2) and o/p-HBA (for 3) respectively. Each ligand was bonded through two oxygen atoms to the metals from a carboxylic acid group and solvent (DMFA/water) was bonded with each Cu (II) atom at axial position by oxygen atoms. Complex-3 was followed in a somewhat different manner by linking two dinuclear Cu(II) complexes through water molecules using hydrogen bonds. Hirshfeld analysis of both complexes was determined and the results indicated that percentage of interaction, the H···H contacts were about 43, 38.5 and 40.5% for complexes 1, 2 and 3 respectively and the percentage of other interactions was significantly lower than these.

Energy efficient CO2 capture in dual functionalized ionic liquids and N-methyldiethanolamine solvent blend system at elevated pressures: Interaction mechanism and heat duties

In this study, three lab synthesized dual functionalized ionic liquids (DFILs) were utilized as promoters to improve the CO2 absorption performance of methyl diethanolamine (MDEA) absorbent under elevated pressures of 2–7 bar. Initially, 5 wt% DFILs containing polyamine cations (triethylenetetramine and diethylenetriamine) and cyclic amine anions (piperazine and imidazole) were blended with 20 wt% MDEA and their physical and chemical properties were examined. The pKa value at 303 K of the blend of [TETAH][Pz] + MDEA is found to be 9.83, which is nearly equal to the industrial 30 wt% monoethanolamine (MEA) solution. The CO2 absorption performance at different temperatures and pressures demonstrated that the blending of 5 wt% DFILs into aqueous MDEA significantly altered both the absorption rate and loading. The percentage loading showed a significant 22% increase in the [TETAH][Pz] promoted aqueous MDEA blend. This is attributed to the high amount of carbamate and bicarbonate formation in the DFILs blended aqueous MDEA as revealed by 13C NMR results. These results were possible due to the highly reactive piperazine anion being a crucial factor in the significant performance of the [TETAH][Pz] blend system. Further, when the regeneration heat duty of all these absorbents was calculated, it was found that MDEA and DFILs blended MDEA absorbents consumed 25.36% and 33.34–22.79% less energy than industrial MEA, respectively along with a low absorbent loss during regeneration thus, [TETAH][Pz] and [TETAH][Im] are potential promoters in an aqueous MDEA solvent system for pressurized capture of carbon dioxide.

Process simulation and energy analysis of synthetic natural gas production from water electrolysis and CO2 capture in a waste incinerator

Power-to-gas (PtG) and carbon capture and utilisation are expected to play a key role in promoting a sustainable energy transition. In this work, a detailed energy analysis of a complete PtG system integrated with a real waste incinerator is performed. A fraction of the renewable electricity and heat produced by the waste incinerator is used in the PtG system to produce hydrogen, which is further converted into SNG by methanation with CO2 recovered from the plant flue gases. A PtG plant able to produce up to 500 m3/h of SNG is considered. A total of six different plant configurations are analysed, obtained by the combination of different electrolysis and post-combustion carbon capture technologies. Specifically, alkaline and PEM electrolysers are considered for the production of hydrogen, while absorption with monoethanolamine solution, absorption with monoethanolamine and ionic liquid solution, and temperature swing adsorption with solid sorbent are selected for carbon capture. The main sections of the PtG system are modelled and the performance of the overall system is evaluated by computing key performance indicators, such as the global energy efficiency and the Specific Plant Energy Consumption for CO2 Avoided (SPECCA). Special attention is also paid to the thermal integration between the methanation unit and the carbon capture unit. The heat produced during the methanation process is sufficient to cover the entire heat demand of the CO2 capture unit in almost all configurations investigated. In particular, thermal integration increases the global energy efficiency by 5–9% and reduces the SPECCA indicator by 5–8%. Considering the thermally integrated configurations, the global energy efficiency is estimated to be between 44.6% and 46.7%, while the SPECCA value ranges from 40.5 MJ/kg to 42.4 MJ/kg. Finally, some technical considerations are given, including the quality of SNG produced and the degradation phenomena in the considered technologies.

A Simplified Kinetic Modeling of CO2 Absorption into Water and Monoethanolamine Solution in Hollow-Fiber Membrane Contactors

The absorption of CO2 from CO2-N2 gas mixtures using water and monoethanolamine (MEA) solution in polypropylene (PP) hollow-fiber membrane contactors was experimentally and theoretically examined. Gas was flowed through the lumen of the module, whereas the absorbent liquid was passed counter-currently across the shell. Experiments were carried out under various gas- and liquid-phase velocities as well as MEA concentrations. The effect of pressure difference between the gas and liquid phases on the flux of CO2 absorption in the range of 15-85 kPa was also investigated. A simplified mass balance model that considers non-wetting mode as well as adopts the overall mass-transfer coefficient evaluated from absorption experiments was proposed to follow the present physical and chemical absorption processes. This simplified model allowed us to predict the effective length of the fiber for CO2 absorption, which is crucial in selecting and designing membrane contactors for this purpose. Finally, the significance of membrane wetting could be highlighted by this model while using high concentrations of MEA in the chemical absorption process.

Novel 2-amino-2-methyl-1-propanol-based biphasic solvent for energy-efficient carbon dioxide capture using tetraethylenepentamine as a phase change regulator

Biphasic solvents are regarded as promising candidates for CO2 capture but still suffer from the deficiency of inferior regenerability, which negatively affects their energy-saving potential. 2-Amino-2-methyl-1-propanol (AMP)-based absorbents have superior regenerability but poor phase-change performance. In this study, an effective strategy that using tetraethylenepentamine (TEPA) to regulate the phase change behavior of an AMP-pentamethyldiethylenetriamine (PMDETA) aqueous solution was proposed, aiming to develop a novel AMP-PMDETA-TEPA (A-P-T) biphasic solvent with good regenerability and excellent phase separation performance. The A-P-T biphasic solvent could realize a high CO2 loading of 0.73 mol mol−1 and a high desorption efficiency of 75.3%. Its sensible heat requirement significantly decreased to 0.14 GJ·ton−1 CO2, 78.1% less than the monoethanolamine solution. The 13C NMR characterization and quantum chemistry calculations indicated that with the introduction of TEPA, high polar TEPA-associated products were generated, which broke the original assimilation state of the A-P-T system and drove it to undergo phase change. Since the TEPA-associated products had a strong affinity to other CO2-captured products and H2O, they gathered together to form the CO2-rich phase. In contrast, less polar PMDETA showed a relatively weak affinity to the TEPA-associated products and was solely separated from the solution to form the CO2-lean phase.

Energy-efficient carbon dioxide capture using piperazine (PZ) activated EMEA+DEEA water lean solvent: Performance and mechanism

Water vapor contained in industrial waste gas will be accumulated in non-aqueous amine solvents when used for CO2 capture and subsequently affect capture efficiency. While Piperazine (PZ) could be considered as an activator of the solution. Hence the effect of different contents of water and PZ added into the non-aqueous amine solvents on the CO2 capture performance has been investigated. 13C NMR has been used to identify the compounds present in aqueous CO2-rich amine solvents to characterize the mechanism of reactions. The energy consumption using 2-(ethylamino)ethanol (EMEA) water-lean amine solvent and aqueous monoethanolamine (MEA) solution was tested and compared on lab-scale, and further a comprehensive evaluation in a bench-scale pilot plant has been performed; It was found that the regeneration efficiency of the solution was reduced by approximately 10% when the water content was 10 wt%. The addition of PZ can recover the regeneration efficiency of the solvent to 94.2%. And its energy consumption was reduced by about 45% compared to the aqueous MEA solution in a 72-hour continuous absorption-desorption experiment. The results demonstrated that the aqueous PZ solution could improve the regeneration efficiency by involving in the proton transfer process. This work has proven that the blend of water-lean amine solvent and PZ is a novel, energy-efficient absorbent for CO2 capture.

Mass transfer dynamics of single CO2 bubbles rising in monoethanolamine solutions: Experimental study and mathematical model

Carbon dioxide (CO2) absorption into amine-based absorbents is a widely used method for carbon emission reduction to deal with global warming problems. The intensification of the absorption process relies on an in-depth understanding of the mass transfer mechanisms between CO2 gas and the reaction media. However, the influence of products of a chemical reaction on mass transfer dynamics is usually underestimated. In this study, we perform research studies on the absorption process of single CO2 bubbles rising in monoethanolamine (MEA) solutions. Firstly, we perform an experimental study to visualize and measure the spatial position and the diameter of the bubbles using the high-speed camera. We observe a special phenomenon that the CO2 bubble diameter rapidly decreases to a nearly constant value in MEA solutions, and the terminal bubble diameter increases with the MEA concentration. Based on the phenomenon, we divide the absorption process into two stages. One is the mass transfer enhancement stage, where the bubble diameter decreases rapidly. The other is the mass transfer deterioration stage, where the bubble diameter remains almost constant. Furthermore, we propose an elaborate mass transfer dynamics model considering the combined effect of chemical reaction kinetics and reaction-induced bubble surface contamination. Finally, a well-predictive performance by the mass transfer dynamics model is validated by experiment. The findings of this study are of theoretical and practical significance for the mass transfer in gas–liquid reactive flow and multiphase reactor design.

Integration of solid acid catalyst and ceramic membrane to boost amine-based CO2 desorption

Amine-based absorption has matured into an established technology for CO2 capture from fossil fuel power plants. However, high energy consumption for CO2 desorption remains a challenge. Herein, we report a promising integration of a solid acid catalyst (i.e., HZSM-5) filled into a vapor permeable-liquid impermeable tubular α-Al2O3 ceramic membrane for boosting CO2 desorption from aqueous monoethanolamine (MEA) solution. Experiments were conducted to investigate the effects of catalyst weight, temperature, pressure, liquid flow rate and CO2 loading on CO2 desorption rate and energy consumption. Furthermore, 60 runs of cyclic tests were carried out to assess the stable CO2 desorption rate and the thermal and chemical stability of both the HZSM-5 catalyst and the α-Al2O3 membrane. The experiment results demonstrated that the HZSM-5 filled α-Al2O3 ceramic membrane contactor exhibited high CO2 desorption performance and long-term stability. It is anticipated that integration of solid acid catalyst with porous ceramic membrane holds great promise in practical application to boost the CO2 desorption rate and reduce the energy requirement.

Predicting overall mass transfer coefficients of CO2 capture into monoethanolamine in spray columns with hybrid machine learning

In order to avoid the catastrophic effects of global warming, we need to reduce CO2 emissions. Currently, the most mature technology to reduce large industrial CO2 emissions is the absorption of CO2 into aqueous monoethanolamine (MEA) solutions. The process is mostly studied in packed columns, for which many correlations have been offered to predict overall mass transfer coefficients (KGa). Spray columns are less prone to corrosion and were shown to enhance KGa. However, to the best of our knowledge, there are no models to predict KGa in spray columns. Hybrid modelling tools, a combination of machine learning techniques and first-principle information, showed remarkable capabilities in modelling complex systems. In this work, we applied hybrid modelling techniques benchmarking performances of four regressors: Ridge regression, decision tree regressor (DTr), support vector machine regressor (SVMr) and fully connected artificial neural network (ANN). We compared the performances of these modelling techniques with a model developed using the Buckingham Π-theorem, which is the most used state of the art technique to model KGa based on dimensionless numbers. SVMr and DTr showed higher accuracies among the trained models on the test set. SVMr can predict KGa within 6.4% error on the test set, whereas the Buckingham modelling approach resulted in 83 % error. The use of machine learning techniques resulted in predictive models with higher accuracies compared to the Buckingham Π-theorem. Predicting KGa with a higher accuracy allows more control over operational parameters and better column designs.

Reclaiming of Amine CO2 Solvent Using Extraction of Heat Stable Salts in Liquid-Liquid Membrane Contactor

Amine CO2 solvents undergo oxidative degradation with the formation of heat stable salts (HSS). These HSS reduce the sorption capacity of amines and lead to intense corrosion of the equipment. In our work, we propose a membrane-supported liquid-liquid extraction of the HSS from alkanolamines. For this purpose, a hollow fiber membrane contactor was used for the first time. A lab-scale extraction system on the basis of a hollow-fiber liquid-liquid membrane contactor with hollow fiber ultrafiltration polyvinylidenefluoride and polysulfone membranes has been studied. The extraction of the HSS-ions from a 30 wt.% solution of monoethanolamine was carried out using a 0.25-1 M solution of OH-modified methyltrioctylammonium chloride in 1-octanol as an extractant. It has been shown that >90% of HSS ions can be extracted from the alkanolamine solvent within 8 h after extraction. The results obtained confirm the possibility of using membrane extraction with a liquid-liquid membrane contactor for the reclaiming of amine CO2 solvents to increase the general efficiency of carbon dioxide capture.