MEA Concentration Research Articles

A low energy consumption sono-microreactor for regeneration of MEA and MEA/AMP solutions

Ultrasound was applied to a microreactor for CO2 desorption from 30 wt% aqueous amine solutions. The ultrasonic transducer was attached directly to the microchannel in order to achieve the greatest ultrasound irradiation by the solution. The behavior of two-phase flow was assessed by a digital microscope camera, illustrating the formation of gas bubbles and its growing through the microchannel reactor. Effects of MEA concentration, solution flow rate, temperature, and ultrasonic wave’s power on the desorption rate and desorption percentage was evaluated. Desorption percentage showed a direct relationship with temperature, ultrasound power, and concentration of MEA solution but an inverse relationship with the flow rate. In addition to performing the regeneration process at lower temperatures than required by traditional procedures which can reduce solvent damage, 50 % energy saving was obtained using the designed contactor. In the next step, aqueous blended AMP/MEA solutions with two different ratios were assessed. For a 20 wt% AMP + 10 wt% MEA solution at 0.25 mL/min, an energy saving of about 62 % was achieved as compared to the conventional method's benchmark of 30 wt% MEA.

Performance and mechanisms of alkaline solid waste in CO2 mineralization and utilization

CO2 mineral sequestration using alkaline solid waste (ASW) is a promising strategy for synergistically reducing CO2 emissions and reusing industrial waste. However, improvement the carbonation degree still remains challenges due to the sluggish leaching rate of Ca/Mg ion at low pH. To the issues, this study proposed an amine-mediated CO2 absorption and mineralization process with six common ASWs, as well an ecological utilization route of CO2-ASW productions. Experimental results indicated that calcium carbide slag (CS) had greater CO2 mineralization capacity (86.2 g-CO2/kg-CS) than other ASWs, while stirring rate and particle size played a more important role during CO2 capture. Amine-mediated CO2 capture was verified to be more excellent with steel slag (SS) as mineral medium. When the MEA concentration was increased to 2 mol/L, the extraction efficiency of Ca2+ was increased by 35 %, leaded to the CO2 removal efficiency significantly promoted from 49 % to 92 %. The characterization of structural morphology referred spherical aragonite or needle-bar calcite was dominant for the porous mineralization products (30.6 m2/g). High germination index of pea seed (112.1 % at a dose of 10 g/L) inferred the negligible toxicological effects of tiny MEA residue over SS mineralization products, after centrifugally washing treatment. Pea seeds cultivated with mineralized products after centrifugal washing can achieve a growth rate of about 4 mm/d. Overall, this work provides a feasible route to apply the porous CO2-ASWs production into water conservation in arid and sandy land.

Simple model for water wash performance in amine scrubbing for CO2 capture

In amine-based capture systems, a water wash is necessary to remove gaseous amine to minimize atmospheric emissions and maximize amine recovery. Water wash simulation requires rigorous thermodynamic and kinetic models like those for absorption and stripping systems. An offline water wash model has been developed based on simplified thermodynamic and mass transfer assumptions to simulate a single-stage water wash for flue gas from gas-fired turbines with little or no aerosol, and to expedite simulations without needing to utilize process modeling software. Calculation of activity coefficients using both Pitzer–Debye–Hückel and Debye–Hückel theory suggest that the liquid phase in a typical water wash will be ideal due to the dilute concentration of molecular and ionic species.Vapor phase piperazine (PZ) is predicted with a driving force based on the volatility of the free amine that has not reacted with other species or dissociated into its ionic form, and the predicted outlet concentration is nearly identical to that predicted by rigorous Aspen PlusⓇ simulations. The predicted UT FEED outlet concentration is 220 ppb compared to 260 ppb predicted by Aspen PlusⓇ.Single-stage water washes are predicted to have single ppm concentration of MEA leaving the wash outlet flue gas. Amino-methyl-propanol (AMP) is predicted to be reduced to 10–30 ppm by a single-stage wash, and is predicted to be a difficult-to-capture amine without further washing steps. This prediction correlates with published TCM data from an ALIGN-CCUS campaign. Amine compounds at a similar or lower volatility to that of PZ are predicted to be reduced to ppb levels via a single-stage wash.

Designing back propagation neural network to predict CO2 mass transfer enhancement factor of TiO2-MEA/MDEA blended amine nanofluids

This study presented a novel methodology to predict the CO2 absorption enhancement performance of TiO2-Monoethanolamine/Methyl diethanolamine (MEA/MDEA) blended amine nanofluids using back propagation neural network (BPNN) model in artificial neural networks. The absorption enhancement factor of TiO2-MEA/MDEA nanofluid were determined experimentally by a two-step method with various nanoparticle solid contents (0.4–1.4 ​g/L). The results showed that the enhancement factor was firstly increased and then decreased with the rising nanoparticle solid content, and the extreme point appeared at 0.6 ​g/L. Based on the experimental data, a relevant empirical formula and a back propagation neural network (BPNN) model were used to estimate the enhancement factor of nanofluid and both exhibited good applicability. Additionally, an optimization model incorporating genetic algorithm, particle swarm algorithm and adaptive learning rate (C-BPNN) was also proposed to estimate the enhancement factor. Compared with the empirical formula and BPNN, C-BPNN exhibited a higher prediction accuracy (all data R2 ​= ​0.9966) and a faster prediction rate. The weight analysis of key parameters (nanoparticle solid content, concentration of MEA and MDEA) showed that the relative importance of nanoparticle solid content was foremost (42.63%) in the absorption enhancement process. All these results indicate that the neural network can provide a guiding role for the research in the field of nanofluid transfer.

Application of post-combustion carbon capture process in marine diesel engine

ABSTRACT This study has investigated the effect of using a waste heat recovery system and carbon capture process on carbon reduction efficiency and the Energy Efficiency Design Index (EEDI) to reduce carbon emissions from ships. Organic Rankine Cycle (ORC) was used as waste heat recovery and ORC system turbine power was determined at variable engine loads. The effect of system parameters such as exhaust absorber inlet temperature, MEA concentration and flow rate, number of columns on carbon capture performance has been revealed in the carbon capture process. Furthermore, the EEDI was estimated using the existing system, the ORC system configuration, and the utilization of the carbon capture system. It has been determined that the optimal exhaust absorber inlet temperature is 50°C and the carbon capture performance is 95% on average. In the applied system, the EEDI is reduced by 14% with the ORC system and by 90% with the carbon capture system. ORC system turbine output power ranges from approximately 414 kW to 606 kW for variable CCS inlet temperatures for 100% load condition. Thus, the study predicts that the carbon capture system can effectively meet the regulations in case of using fossil fuels in the future.

CFD modeling of MEA-based CO2 spray scrubbing with computational-effective interphase mass transfer description

Great concerns for global warming and stringent regulations have spurred the development of feasible technologies to reduce CO2 emissions from the power generation sector. In thermal power plants, spray scrubbing is one of the most used methods for separating gaseous pollutants, which inspires the idea of applying spray scrubbing in CO2 capture. However, this new idea still necessitates investigation, particularly in developing a novel modeling tool. This motivates us to present the CFD modeling of CO2 spray scrubbing using MEA solution in this work. CO2 spray scrubbing is a complex process. Herein, the established model combines the multiphase flow with interphase transfer and chemical reactions in the Euler-Lagrange framework. To efficiently describe the interphase mass transfer, we proposed a new method based on the thermodynamic consistency between the CO2 equilibrium pressure and the enthalpy of CO2 absorption. Validated by the experimental data, this method can achieve an acceptable balance between accuracy and computational cost. The zwitterion mechanism was employed to describe the chemical reactions. Kinetic analysis shows that E = (1 +Ha2)0.5 can reasonably evaluate the enhancement factor value in a wide range of MEA concentrations. Additionally, the effects of operating parameters on CO2 removal were numerically studied, focusing on mass transfer characteristics. Therefore, the proposed numerical model will be beneficial for facilitating the deployment of CO2 spray scrubbing in the power sector, and the numerical results provide helpful information for design and optimization.

Precipitation behavior, density, viscosity, and CO2 absorption capacity of highly concentrated ternary AMP-PZ-MEA solvents

This study explored potential of highly concentrated AMP-PZ-MEA solvent for capturing CO2 in terms of solvent precipitation, density, viscosity, and CO2 absorption capacity. It was found that most of the studied AMP-PZ-MEA solvents precipitated at high AMP and PZ concentrations and at high CO2 loading. The minimum possible MEA concentration (which can maintain a clear solvent) was 1.5 M for 6 M total amine concentration. It was also observed that an increase of AMP and/or PZ concentration in the 6 M blends induced the solvent precipitation. MEA was the only amine component that can be added to the blends to elevate the total amine concentration from 6 M to 7 M. As a result, the six AMP-PZ-MEA blends were suggested: 2:2.5:1.5, 1.3:3.2:1.5, 0.95:3.55:1.5 (for 6 M) and 2:2.5:2.5, 1.3:3.2:2.5, and 0.95:3.55:2.5 (for 7 M). The proposed blends are corresponding to PZ:AMP molar ratio of 1.25, 2.5, and 3.75, which are much higher than that of the first-generation AMP-PZ-MEA solvents. Regarding the visualized observation, there was no solid sediments observed throughout precipitation and CO2 absorption studies of the six blends. Interestingly, densities of the proposed blends were close to that of 5 M MEA, while their viscosities were much higher than that of 5 M MEA but were close to that of MDEA-PZ and AMP-PZ. Additionally, CO2 absorption capacities of the proposed 6 M and 7 M blends were 56-58% and 64-71% higher than that of 5 M MEA. These numbers are much higher than those of the first-generation AMP-PZ-MEA solvents.

Protonated amines mediated CO2 mineralization of coal fly ash and polymorph selection of CaCO3

The extensive consumption of acid and alkaline reagents is the most critical challenge hindering the development of the pH-swing process for CO2 mineralization. To deal with the problem, the present paper demonstrates the feasibility of using protonated amine as the reagent in coal fly ash (CFA) based leaching-mineralization process. The protonated amine could leach Ca2+ from CFA and be converted into free amine. The free amine was supposed to be in-situ regenerated into protonated amine by grab protons released from the CaCO3 precipitation reaction. 13 typical amines with varying amino types, pKa values, and side-chain length, were selected to systematically investigate the effects of amino groups on Ca2+ leaching performance from CFA, carbonation performance, CaCO3 nucleation, and crystal growth, as well as the process mechanism. Results indicated that effective Ca leaching, CaCO3 precipitation, and protonated amine regeneration were achieved. There was a linear relationship between the Ca utilization efficiency and pKa values of different amines. TEA obtained the highest CaCO3 yield and Ca utilization efficiency of 56.8 % and 16.8 %, respectively. In addition, amines provided excellent control of the size, polymorph, and morphology of the CaCO3 product. The primary amino group had a more pronounced effect on vaterite stabilization than secondary and tertiary ones. Introducing a side chain could promote the vaterite transforming to calcite and increasing chain length could decrease the vaterite particle size. Moreover, the maximal utilization efficiency in MEA was 15.9 % at conditions: 160 g/L solid to liquid ratio, 58 % degree of protonation, and 2.0 mol/L MEA concentration.

CFD modeling on the chemical absorption of CO2 in a microporous tube-in-tube microchannel reactor

In this paper, combining recently developed mesoscale mass transfer model with reaction kinetics, the chemical absorption process of CO2 by MEA solution in a microporous tube-in-tube microchannel reactor (MTMCR) was numerically simulated for the first time. The predicted values by CFD simulations were in agreement with the public experimental data (Na-Na Gao et al., Ind. Eng. Chem. Res., 2011). The distributions of CO2 removal efficiency and volumetric mass transfer coefficient under different gas flow rate, solvent flow rate, solvent temperature, and MEA concentration were analyzed. Among these factors, MEA concentration had a more significant influence on the CO2 chemical absorption. The KGa in the MTMCR was more than 200 times of that in the randomly packed bed under the similar operating conditions. The local mass transfer rate of chemical absorption was one order of magnitude higher than that of physical absorption. This research work could lay a theoretical foundation for the simulation of the complex gas–liquid systems including the chemical absorption by CFD method.

Study on the hydrothermal recovery characteristics of nano-ceramic membranes on regenerative gas

In view of the large energy consumption of the regeneration process in the chemical absorption decarburization process, on the basis of the enrichment classification flow process, the nanoscale ceramic film is used as a new heat exchanger between the enriched liquid and the regeneration gas. The porous ceramic film is capable of coupling thermal-mass transfer to effectively recover part of the water vapor and the heat carried in the regeneration gas, so as to reduce the regenerative energy consumption of the system. The effects of parameters such as regeneration temperature, flow rate, molar fraction of water vapor, and MEA enrichment temperature, flow rate, and MEA concentration of shunt on the hydrothermal recovery effect of ceramic membranes of different pore sizes and lengths were studied by using the heat recovery flux and water recovery rate as the indicators. The results show that the hydrothermal recovery performance of the ceramic membrane increases with the increase of MEA enrichment flow, but decreases significantly with the increase of the enrichment temperature. At the same time, with the increase of regenerative gas velocity and the molar fraction of water vapor in the regenerative gas, the heat recovery flux will increase. The heat recovery performance of the 10 nm ceramic membrane is better than that of the 20 nm ceramic membrane.

Kinetics of CO2 absorption into ethanolamine + water + ethanol system—mechanism, role of water, and kinetic model

The kinetics of CO2 absorption in ethanolamine (MEA) + H2O + ethanol systems was investigated using stopped-flow apparatus. The first-order reaction rate constant (k0) values were tested with varying H2O and MEA concentrations. Transiting from the aqueous to non-aqueous solvents, the k0 decreases and the reaction order for MEA shifts from 1.05 to 1.88. The zwitterion mechanism with the rate-limiting step of deprotonation was used to explore the role of water and its effect. Results showed that water could impact reactions through direct involvement and changing solvation environment. An improved kinetic model based on the zwitterion mechanism was obtained to indicate the quantitative influence of H2O concentration on the reaction kinetics of MEA + H2O + ethanol systems. The predicted values from the model well agreed to the experimental data with the average absolute relative difference of 6.73%. This study highlights the important effects of water on the reaction kinetics of CO2 absorption into water-lean amine solutions.

Experimental investigations and the modeling approach for CO2 solubility in aqueous blended amine systems of monoethanolamine, 2-amino-2-methyl-1-propanol, and 2-(butylamino)ethanol.

In this work, new CO2 solubility data on three types of aqueous amine blends were reported to complement existing databases. The experiments were conducted at temperatures of 313K (absorption condition) and 363K (desorption condition). The effect of the MEA concentration on the CO2 solubility in several amine blends at low CO2 partial pressure (8 to 50.65kPa) were studied in this work, including 0.1, 0.3, 0.5mol/L MEA + 2mol/L AMP; 0.1, 0.3, 0.5mol/L MEA + 2mol/L BEA; and 0.1, 0.3, 0.5mol/L MEA + 1, 2mol/L AMP + 1, 2mol/L BEA. Besides, an additional group of equilibrium CO2 solubility data were conducted at 298K in order to estimate the heat of CO2 absorption of the blended solvents at a temperature range from 298 to 313K. A new simplified Kent-Eisenberg model was developed for the predictions of blended solvents, and a multilayer neural network model with Levenberg-Marquardt backpropagation algorithm was developed upon five hundred reliable published experimental data. The predictions from two methods are both in good agreement with the experimental CO2 solubility data.

Comparative assessment of the pulping potentials of soda and mea processes for the development of paper-pulp from sugarcane bagasse

Pulping trials were carried out using MEA and the soda process comparing their pulping potentials. The operating conditions such as the concentration of the cooking liquor (50%, 75%, 100%) for MEA and (10%, 15%, 20%) for NaOH, the maximum cooking temperature (150oC, 160oC, 170oC) and cooking time (60, 90, 120minutes) for both processes were investigated systematically to establish optimal pulping conditions. The agro-biomass used in this investigation is Sugarcane Bagasse viewed as alternative raw material for pulp and paper production. The lignin content of Bagasse (19.5%) was low; indicating that Bagasse should be easier to pulp. The optimum cooking conditions (independent variables) for MEA pulping were 75% MEA concentration, 150oC cooking temperature and 90 minutes cooking time. Excel 2013 was used to analyze the effect of independent variables on yield of bagasse pulp and properties of furnished paper from MEA process in comparison with the Soda process which include tear index, tensile index, burst index and folding endurance with errors less than 15% in all cases. The Kappa number range (12.7-16.9), viscosity (270-870 ml/g) and brightness (62.1-93.2%) of bagasse pulp are appropriate for high-brightness printing and writing papers. The physical properties of furnished paper, tear index (13.4 mN.m2/g), tensile index (71Nm/g), Burst index (4.8 KN/g) and folding endurance (82) recommend the cellulosic pulp from Sugarcane Bagasse obtained from the MEA process for strengthening the virgin fiber in recycled papers and also for developing certain types of printing and packaging papers. Due to the awareness towards the negative impact of kraft mill’s effluent to the environment recently, soda pulping started to regain its popularity among the pulp mills especially non-wood based pulp mills. MEA process is more economically attractive given its high pulp yield, despite the significant increase in chemical demand for bleaching. MEA pulping is a good alternative to soda pulping furnishing high pulp yield with less cooking temperature, i.e. 150oC, thereby saving a considerable amount of energy with less odoriferous pollutants and pollution load associated with the soda process.

MEA-conversion of agro-wastes to paper-pulp: Optimization of pulping conditions

This paper investigates the potentials of a novel environmental friendly pulping (Monoethanoleamine-MEA) process in comparison with conventional Soda and Kraft pulping processes in furnishing high yield pulp from agro-biomass for the formation Papers and other paper products. The pulping investigation had three (3) factors at three (3) different levels each: Factor 1, MEA concentration (50, 75 and 100%); Factor 2, cooking time (60, 90 and 120minutes); Factor 3, liquor-biomass ratio (4, 6 and 8) at a fixed temperature of 123±5oC. Consequently, the experimental design had 27 treatments (3×3×3) and 2 replicates. By using a central composite factorial design, equations relating the dependent variable (pulp yield) to the different independent variables (cooking temperature, cooking time and liquor concentration) were derived; reproducing the experimental result for the dependent variable with errors less than 15%. Models were evaluated to analyze the effect of experimental pulping conditions on pulp properties and evaluate the effect of these properties on furnished paper samples. Pulp Screened Yields was in the range of 42.45 to 49.18% calculated on oven dry (O.D) basis. The resultant pulps obtained from the cooking operation had very good appearance, exhibiting fairly bright color, with slow tendency to felt, thereby making drainage and consequent paper making time short. It is recommended that the cellulosic pulp obtained from MEA pulping of EFB is appropriate as virgin fiber for strengthening secondary fibers in recycled papers and also for developing certain types of writing, printing and packaging paper materials. Conclusive investigation on EFB fiber in this research study asserts that it has a promising future (when used in blend with certain long fiber plant i.e. kenaf) in substituting wood in the pulp, paper and fiber- board industry. Conclusive investigation also asserts from over-all parameter achieved that monoethanolamine-MEA when used as the main de-lignifying agent furnished pulp and subsequent paper with good strength properties that can adequately match those from conventional (i.e. kraft and soda) processes and because it works without the use of sulphur compounds, it attributes a particular benefit of simple MEA recovery by distillation, allowing black liquor combustion to be dispensed and the dissolved lignin recovered without negative impact on the environment.

Dynamic modelling based on surface renewal theory, model validation and process analysis of rotating packed bed absorber for carbon capture

Rotating packed beds can reduce the equipment size and costs in solvent-based carbon capture. However, difficulties are encountered when modelling rotating packed beds due to turbulent fluid flows inside rotating packed beds and the cross-sectional area of mass transfer unit that changes with radius. This study aims to develop a validated dynamic model of a rotating packed bed absorber and to carry out process analysis through steady state and dynamic simulations. Innovatively, the dynamic model was developed based on surface renewal theory for mass transfer. The model can calculate distributed mass transfer coefficients and other key variables related with absorption performance. Experiments were carried out and new experimental data for the rotating packed bed absorber under realistic operating conditions were obtained for model validation. Process analysis about the effects of key operational variables such as rotating speed, liquid-gas ratio and solvent concentration on absorption performance was performed with benchmark MEA solvent. It was found that the optimal MEA concentration is around 70 wt%. Dynamic simulation results reveal that the RPB absorber has fast responses for process changes. This new distributed dynamic model and the insights obtained through process simulation will promote rotating packed bed technology towards its industrial deployment in large scale carbon capture processes.

Investigation of Factors Affecting the Efficiency of Carbon Dioxide Removal in a Single Perforated Sieve Tray Column

An experimental work was carried out for the recovery of carbon dioxide in monoethanolamine solution (MEA) using pilot plant of perforated sieve tray column. The effect of MEA concentration, carbon dioxide ratio in the gas phase, liquid flow rate, gas flow rate and CO2 loading in the absorption solution was investigated. The results show that the efficiency of recovery increased by increasing the concentration of MEA and better removal efficiency can be achieved by increasing the liquid flow rate and the contact time between CO2 and the absorbent and that can be happened by decreasing the air flow rate.

Cost Reduction Study for MEA based CCGT Post-Combustion CO <sub>2</sub> Capture at Technology Center Mongstad

A campaign was carried out by Technology Center Mongstad (TCM) and its owners in the amine capture plant to study various cost saving operating options relevant for combined cycle gas turbine plants. The owners chose MEA as solvent for this test because it is a well-studied solvent system with no commercial constraints regarding sharing of data. Learnings obtained from MEA studies are also expected to be of relevance for other solvent systems. During this campaign the main focus was on thermal energy optimization at different flue gas flow rates through the absorber column and MEA emissions, with target for reduced CAPEX and OPEX. During the campaign, new options such as a rich solvent bypass to stripper overhead and higher concentration of MEA (up to 38wt%) were tested. Tests were carried out to identify plant configurations and process parameters with the potential for CAPEX and OPEX reduction in a post-combustion carbon capture plant. Significant cost of CO2 avoided reductions were achieved compared to the previous TCM campaigns for MEA.

In Vitro Determination of Antimicrobial and Hypoglycemic Activities of Mikania cordata (Asteraceae) Leaf Extracts

Infectious diseases and diabetes mellitus are counted responsible for a substantial amount of mortality among the human population. The current study was performed to detect the antimicrobial activities and hypoglycemic potential of Mikania cordata (Asteraceae) leaves extracted into aqueous media and several organic solvents (ethyl acetate and methanol). The ethyl acetate extract of Mikania cordata (MEA) leaves was observed to possess significantly ( p ≤ 0.05 ) greater antimicrobial capabilities (susceptible against Bacillus cereus ATCC 11778 and Staphylococcus aureus ATCC 25923) when compared with that of the methanol (MME) and aqueous extracts (MDW) which were assessed based on Kirby-Bauer disk diffusion assay. The minimum inhibitory concentration of MEA (against B. cereus, S. aureus, and Escherichia coli ATCC 25922) and MME (against B. cereus, S. aureus, E. coli, and Candida albicans ATCC 10231) lies in a similar range of 1.13 > MIC>0.56 mg/ml. In the present study, a single compound (from MEA) of Rf value 0.64 was isolated by thin-layer chromatography (TLC) that was responsible for the zone of inhibition against B. cereus (20.3 ± 0.3 mm). The results of this study also depicted the antihyperglycemic properties of M. cordata leaves which followed the same trend as the commercial drug Metformin in a glucose concentration-independent manner when tested in a glucose uptake assay by yeast cells. Therefore, it is evident that Mikania cordata is a reservoir of useful bioactive compounds which with further research will be paving the path for drug commercialization. This is the first record of TLC-based isolation of antimicrobial compounds of M. cordata and analysis of the hypoglycemic properties of M. cordata leaves.

Experimental investigation of hydrodynamic parameters and bubble characteristics in CO2 absorption column using pure ionic liquid and binary mixtures: Effect of porous sparger and operating conditions

For first time, bubble size distribution, bubble shape, bubble orientation, mean bubble size (d32), gas holdup (εg) and interfacial area in pure IL [BMIM][BF4] were compared with those in its binary mixtures with MEA and MeOH. Experiments were performed in small-scale cylindrical bubble column with a porous sparger using a high-speed image capture system. Further, to investigate effects of sparger pore size, column diameter, temperature and gas flow rate, experiments were performed employing gas-pure IL system. Compared with pure IL, d32 in binary mixtures was smaller, which decreased with increasing MEA or MeOH concentration, whereas, gas holdup and interfacial area were increased. MeOH exhibited profound effect as compared to MEA. In gas-pure IL, sparger pore size and temperature significantly influenced on aforementioned parameters. Correlations were proposed for predicting d32 and εg in pure IL for two different column sizes demonstrating their applicability in higher column dimensions and scaling-up.

New Insights and Assessment of Primary Alkanolamine/Sulfolane Biphasic Solutions for Post-combustion CO2 Capture: Absorption, Desorption, Phase Separation, and Technological Process

The sulfolane was, surprisingly, found to be a universal phase splitting solvent in a serial of aqueous primary alkanolamine solution for CO2 removal, the reaction product of carbamate and hydrophilicity of amine can be the key factor for CO2 triggering phase change, also the phase change can have significant effect on CO2 absorption performance. To comprehensively understand the effect of phase change on absorption, stripping and phase separation performance of primary alkanolamine solution for CO2 capture, MEA sulfolane-based solution was chosen as typical biphasic system for investigation. First, the experimental results revealed that phase change can dramatically decrease the absorption rate and lead to less CO2 capacity in an absorption process. Second, the enriched MEA in separated solution can substantially decrease the energy consumption for CO2 stripping, but exorbitant concentration of MEA can significantly reduce the CO2 removal efficiency in a quasi-cycle of absorption and desorption. Third, t...