And 2-amino-2-methyl-1-propanol Research Articles

이산화탄소 5 ton/day 흡수분리 Pilot Plant 운전 특성

석탄화력 발전소의 연소 배가스를 시간당 1,000 <TEX>$Nm^3$</TEX>을 처리할 수 있는 이산화탄소 분리용 pilot plant를 설치하여 화학흡수제인 mono-ethanolamine(MEA)과 2-amino-2-methyl-1-propanol(AMP)를 이용해서 운전특성을 연소 배가스 유량과, 흡수용액 순환유량을 주 실험변수로 분석하였다. MEA 20 wt%를 기준으로 연소 배가스 유량이 100 <TEX>$m^3/hr$</TEX> 감소할수록 이산화탄소 제거율이 평균 6.7% 증가하였으며 흡수용액 순환유량이 1,000 kg/hr 증가에 따라 이산화탄소 제거율은 약 2.8% 상승하였고 <TEX>$110^{\circ}C$</TEX> 재가열기 온도에서 90% 이상의 이산화탄소 제거효율을 나타냈다. MEA가 AMP보다 높은 제거효율을 보였고 MEA(20 wt%) 실험에서 이산화탄소의 제거율이 75.5%인 ASPEN plus의 모사 결과보다 10% 높은 85.5%로 나타났다. The pilot scale experiments can handle the flue gas up to 1,000 <TEX>$Nm^3/hr$</TEX> for separation of carbon dioxide included in real flue gas at coal-fired power plant. The operational characteristics was analyzed with the main experimental variables such as flue gas flow rate, absorbent circulation rate using chemical absorbents mono-ethanolamine( MEA) and 2-amino-2-methyl-1-propanol(AMP). The more flue gas flow rate decreased in 100 <TEX>$m^3/hr$</TEX> in the MEA 20 wt% experiments, the more carbon dioxide removal efficiency was increased 6.7% on average. Carbon dioxide removal efficiency was increased approximately 2.8% according to raise of the 1,000 kg/hr absorbent circulation rate. It also was more than 90% at <TEX>$110^{\circ}C$</TEX> of re-boiler temperature. Carbon dioxide removal efficiency of the MEA was higher than that of the AMP. In the MEA(20 wt%) experiment, carbon dioxide removal efficiency(85.5%) was 10% higher than result(75.5%) of ASPEN plus simulation.

Study on the improvement of the capacity of amine-impregnated commercial activated carbon beds for CO2 adsorbing

Amine-based chemicals were impregnated onto activated carbon particles to improve its natural adsorption ability and selectivity to adsorb CO2 from gas mixture stream. Characterization results achieved by measuring the surface area with ASAP 2020 showed that the amine-based chemicals blocked the mostly micropore pores of the activated carbon particles. The amine-based chemicals used in this study were, monoethanolamine (MEA) and 2-amino-2-methyl-1-propanol (AMP). The impregnation process and the subsequent blockage reduced the surface area of the activated carbon particles significantly but on the other hand enhanced the adsorption capacity and selectivity of the activated carbon for CO2 adsorption. Elemental analysis results using energy-dispersive X-ray spectroscopy showed that the impregnation process managed to attach the reactive N2 molecules onto the surface and inside the pores of the activated carbon particles. Images from field emission scanning electron microscope showed that due to impregnation process most of the pores of the activated carbon particles had been blocked by the MEA and AMP molecules. Sweeping exhausted non-impregnated activated carbon beds with 60ml/min pure nitrogen for 4h was enough for these beds to regain their original adsorption capacity but in contrast it was not enough to regenerate exhausted AMP, MEA-impregnated activated carbon beds to regain their original adsorption capability.

Membrane Contactor as Reactor for CO2 Capture

A novel composite solution consisting of N-methylmonoethanolamine (MM-EA) and 2-amino-2-methyl-1-propanol (AMP) as a CO2 absorbent was proposed. Coupling process of membrane contactor and the composite solution was investigated. The performance of the coupling was experimentally compared between the single and composite solution. Overall mass transfer coefficients were determined. Effects of various factors, such as flow rates and operation temperatures on mass transfer of membrane contactor, were studied. Comparison of prediction for overall mass transfer coefficients using a resistance in series model with experimental values was performed. Results show that performance of the composite solution is evidently better than that of the single MMEA solution. The overall mass transfer coefficient with the composite solution is much higher than that with the single MMEA solution. Higher operation temperature can enhance mass transfer of membrane contactor. Operation parameters such as flow rates can promote mass transfer, but the promotion is limited. Enhance of mass transfer relies essentially on chemical reaction. Model values are in good agreement with experimental ones.

Modeling of carbon dioxide absorption in a gas/liquid membrane contactor

In this study, the behavior of CO2 absorption in flat sheet membrane contactors is developed. Physical and chemical absorption of CO2 in co-current and counter-current flow were studied using both distilled water and 2-amino-2 methyl 1-propanol (AMP) as a solvent in the model. The effect of flow pattern, solvent type and gas and liquid velocity on absorption of carbon dioxide through the membrane contactor is obtained. The results indicate that the use of AMP instead of water leads to a better separation for carbon dioxide. Furthermore, unlike the liquid velocity, lower value of gas velocity showed higher performance for absorption.

Carbon dioxide absorption in a cross-flow rotating packed bed

This work investigates the feasibility of applying the cross-flow rotating packed bed (RPB) to the removal of carbon dioxide (CO 2) by absorption from gaseous streams. Monoethanolamine (MEA) aqueous solution was used as the model absorbent. Also, other absorbents such as the NaOH and 2-amino-2-methyl-1-propanol (AMP) aqueous solutions were compared with the MEA aqueous solution. The CO 2 removal efficiency was observed as functions of rotor speed, gas flow rate, liquid flow rate, MEA concentration, and CO 2 concentration. Experimental results indicated that the rotor speed positively affects the CO 2 removal efficiency. Our results further demonstrated that the CO 2 removal efficiency increased with the liquid flow rate and the MEA concentration; however, decreased with the gas flow rate and the CO 2 concentration. Additionally, the CO 2 removal efficiency for the MEA aqueous solution was superior to that for the NaOH and AMP aqueous solutions. Based on the performance comparison with the conventional packed bed and the countercurrent-flow RPB, the cross-flow RPB is an effective absorber for CO 2 absorption process.

Nucleophilicity and Accessibility Calculations of Alkanolamines: Applications to Carbon Dioxide Absorption Reactions

Both nucleophilicities and accessibilities of three alkanolamines [monoethanolamine (MEA), (2-(methylamino)ethanol (MAE), and 2-amino-2-methyl-1-propanol (AMP)] were calculated to predict their reactivities with CO(2). After DFT geometry-optimization calculations, the global, group, and atomic nucleophilicities of each amine were obtained using MP2 quantum mechanical calculations. Only global nucleophilicity matched an experimental pK(a) order (MAE > AMP > MEA). However, it failed to predict the slow rate of the sterically hindered AMP and the order of rate constants, MAE > MEA > AMP. The accessibilities of amines to CO(2) have been calculated by MD simulations by monitoring collisions at the reaction centers: N atoms in amines and C in CO(2). The accessibility results indicate that global nucleophilicity needs quantitative correction for steric effects to predict better reactivities of amines with CO(2).

Capture of carbon dioxide by amine-impregnated as-synthesized MCM-41

The novel carbon dioxide (CO 2) adsorbents with a high capture efficiency were prepared through impregnating the as-synthesized MCM-41 with three kinds of amines, namely diethylenetriamine (DETA), triethylenetetramine (TETA) and 2-amino-2-methyl-1-propanol (AMP). The resultant samples were characterized by small angle X-ray diffraction and low temperature N 2 adsorption. The synthesis way not only saves the energy or extractor to remove the template but also is environmentally friendly due to the absence of the potential pollutants such as toluene. CO 2 capture was investigated in a dynamic packed column. The sample impregnated by TETA showed the highest adsorption capacity, approximately 2.22 mmol/g at 60°C due to its highest amino-groups content among the three amines. The CO 2 adsorption behavior was also investigated with the deactivation model, which showed an excellent prediction for the breakthrough curves.

Modeling solubility of acid gases in alkanolamines using the nonelectrolyte Wilson-nonrandom factor model

The nonelectrolyte Wilson-nonrandom factor local composition model (N-Wilson-NRF) by Haghtalab and Mazloumi is applied for modeling the vapor–liquid equilibrium of the acid gases (CO 2 and H 2S)–alkanolamine–water systems. The model is used to calculate the nonideality of species in liquid phase through the activity coefficient equations. In this work, we use the N-Wilson-NRF model for short-range forces in the aqueous electrolyte system of alkanolamines by using the concept of ion-pair. For the long-range interaction the Pitzer–Debye–Hückel theory is applied. The model is used to correlation of the solubility data of CO 2 and H 2S in aqueous monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA) and 2-amino-2methyl-1-propanol (AMP) systems over wide range of temperature (0–140 °C), partial pressure (0.001–1000 kPa) and acid gases loading (0.001–1.0 mol gas/mol amine). To show the predictability of the model, the interaction parameters without any additional adjustable parameters are used to predict the solubility of CO 2 in aqueous AMP solution at different conditions. The results of the model show a very good agreement with the experimental data.

Evaluation of alkanolamine solutions for carbon dioxide removal in cross-flow rotating packed beds

The removal of CO(2) from a 10 vol% CO(2) gas by chemical absorption with 30 wt% alkanolamine solutions containing monoethanolamine (MEA), piperazine (PZ), and 2-amino-2-methyl-1-propanol (AMP) in the cross-flow rotating packed bed (RPB) was investigated. The CO(2) removal efficiency increased with rotor speed, liquid flow rate and inlet liquid temperature. However, the CO(2) removal efficiency decreased with gas flow rate. Also, the CO(2) removal efficiency was independent of inlet gas temperature. The 30 wt% alkanolamine solutions containing PZ with MEA were the appropriate absorbents compared with the single alkanolamine (MEA, AMP) and the mixed alkanolamine solutions containing AMP with MEA. A higher portion of PZ in alkanolamine solutions was more favorable to CO(2) removal. Owing to less contact time in the cross-flow RPB, alkanolamines having high reaction rates with CO(2) are suggested to be used. For the mixed alkanolamine solution containing 12 wt% PZ and 18 wt% MEA, the highest gas flow rate allowed to achieve the CO(2) removal efficiency more than 90% at a liquid flow rate of 0.54 L/min was of 29 L/min. The corresponding height of a transfer unit (HTU) was found to be less than 5.0 cm, lower than that in the conventional packed bed.

Carbon dioxide capture by blended alkanolamines in rotating packed bed

Abstract The capture of CO2 from a 10 vol% CO2 gas by chemical absorption with aqueous solutions containing 30 wt% of single and mixed monoethanolamine (MEA), 2-(2-aminoethylamino)ethanol (AEEA), piperazine (PZ), and 2-amino-2methyl-1-propanol (AMP) in a rotating packed bed (RPB) was studied. The RPB had an inner diameter of 7.6 cm, an outer diameter of 16 cm, and a height of 2 cm. The CO2 capture efficiency was found to increase with increasing temperature in a range of 303 to 333 K. It was also found to be dependent on rotating speed, gas flow rate, and liquid flow rate. The 30 wt% mixed alkanolamine solutions containing MEA or AEEA with at least 10 wt% PZ were the appropriate absorbents compared with the single alkanolamine and the mixed alkanolamine solutions containing AMP. A higher portion of PZ in a mixture was more favourable to CO2 capture. Because of short contact time in a RPB, alkanolamines with high reaction rate with CO2 are suggested to use. For the solutions containing 15 wt% MEA or AEEA and 15 wt% PZ, the highest gas flow rate allowed to achieve a capture efficiency more than 90% were 30 L/min at a solution of 100 mL/min and 50 L/min at a solution of 300 mL/min. The corresponding height transfer units were found to be less than 2.0 cm, significantly lower than those in a conventional packed bed absorber.

Integration of CO2 capture unit using blended MEA–AMP solution into coal-fired power plants

This study evaluated feasibility of using blended MEA and 2-amino-2-methyl-1-propanol (AMP) in the CO2 capture unit that is integrated into a supercritical coal-fired power plant. The evaluation was carried out by using the integrated power plant and gas absorption model developed at the University of Regina, Canada. Simulation results were presented in terms of energy requirement for solvent regeneration, sizes of absorber and regenerator, cost of CO2 capture and energy penalty. Conventional MEA process was also simulated and used as a benchmark for a comparison purpose.

Theoretical studies on separation of CO2 by single and blended aqueous alkanolamine solvents in flat sheet membrane contactor (FSMC)

Abstract Absorption of carbon dioxide by different single and blended alkanolamine solvents were studied theoretically using flat sheet membrane contactor. The solvents considered for this study include aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA) and 2-amino-2-methyl-1-propanol (AMP) as well as aqueous blends MEA or DEA with AMP or MDEA. Simulation study shows that the absorption flux for CO2 with aqueous solution of MEA was the highest among the single amines solvents studied. There is an increase in CO2 absorption flux with the increase in the concentration of MEA or DEA in the blends of (MEA + MDEA), (DEA + MDEA) and (MEA + AMP). For the (DEA + AMP) system the flux of CO2 is found to have a marginal effect with different blend compositions. The blends of (MEA + MDEA) and (MEA + AMP) are found comparatively suitable for the absorption of CO2 among all the blends. The performance of flat sheet membrane contactor is found to be better than that of hollow fiber membrane contactor if only the absorption flux of CO2 in the amine is considered.

Prediction of equilibrium solubility of CO2 in aqueous alkanolamines using differential evolution algorithm

AbstractThe design of sour‐gas treating processes with alkanolamine solvents requires knowledge of the vapour–liquid equilibrium (VLE) of the aqueous acid gas–alkanolamine systems. Representation of the experimental data with a thermodynamically rigorous model is required, so that one can systematically correlate and predict the VLEs of these systems. The modified Clegg–Pitzer equations have been used to correlate and predict the VLE of CO2 in the aqueous N‐methyldiethanolamine (MDEA) and 2‐amino‐2‐methyl‐1‐propanol (AMP) systems. Differential evolution (DE), an evolutionary computational technique, has been used for parameter estimation of the developed VLE model in an effort to predict the VLE of CO2 in aqueous MDEA and AMP solutions with a comparable accuracy to that by using the non‐traditional simulated annealing (SA) and deterministic technique like Levenberg–Marquardt (LM), if not better. In this work, the DE/rand‐best/1/bin strategy has been used for finding near global minimum solutions to the multivariable optimization problem as a part of the numerical solution of the developed model.

Absorption of carbon dioxide by the absorbent composed of piperazine and 2-amino-2-methyl-1-propanol in PVDF membrane contactor

This paper tests the performance of microporous polyvinylidinefluoride (PVDF) hollow fiber in a gas absorption membrane process (GAM) using the aqueous solutions of piperazine (PZ) and 2-amino-2-methyl-1-propanol (AMP). Experiments were conducted at various gas flow rates, liquid flow rates and absorbent concentrations. Experimental results showed that wetting ratio was about 0.036% when used with the aqueous alkanolamine solutions, while that was 0.39% with aqueous piperazine solutions. The CO 2 absorption rates increased with increasing both liquid and gas flow rates at N Re < 20. The increase of the PZ concentration showed an increase of absorption rate of CO 2. The CO 2 absorption rate was much enhanced by the addition of PZ promoter. The resistance of membrane was predominated as using a low reactivity absorbent and can be neglected as using absorbent of AMP aqueous solution. The resistance of gas-film diffusion was dominated as using the mixed absorbents of AMP and PZ. An increase of PZ concentration, the resistance of liquid-film diffusion decreased but resistance of gas-film increased. Overall, GAM systems were shown to be an effective technology for absorbing CO 2 from simulated flue gas streams, but the viscosity and solvent–membrane relationship were critical factors that can significantly affect system performance.

Removal of CO2 by Single and Blended Aqueous Alkanolamine Solvents in Hollow-Fiber Membrane Contactor: Modeling and Simulation

A theoretical analysis to capture CO2 using different aqueous single and blended alkanolamine solutions in a hollow-fiber membrane contactor has been performed. The aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), and 2-amino-2-methyl-1-propanol (AMP), as well as aqueous blends of MEA or DEA with AMP or MDEA are considered. The aqueous solution of MEA has the highest CO2 absorption flux among the single amine solutions. For the absorption in the blends of (MEA + MDEA), (DEA + MDEA), and (MEA + AMP), the flux increases as the concentration of MEA or DEA increases. For the (DEA + AMP) system, the flux of CO2 is observed to be almost constant with different blend compositions. The absorption fluxes of CO2 in the blends of (MEA + MDEA) and (MEA + AMP) are higher, compared to those in other blends.

Density and Viscosity of Aqueous Solutions of (N-Methyldiethanolamine + Piperazine) and (2-Amino-2-methyl-1-propanol + Piperazine) from (288 to 333) K

The densities and viscosities of aqueous blends of piperazine (PZ) with N-methyldiethanolamine (MDEA) and 2-amino-2-methyl-1-propanol (AMP) have been measured at (288, 293, 298, 303, 308, 313, 318, 323, 328, and 333) K. The total amine mass fraction in all solutions was kept at 30 % in view of recent interest in using concentrated amine solutions in gas treating. Correlations for the density and viscosity of the ternary mixtures are presented as a function of temperature and amine concentration.

Kinetics of carbon dioxide absorption and desorption in aqueous alkanolamine solutions using a novel hemispherical contactor—I. Experimental apparatus and mathematical modeling

This two-parts paper summarizes the experimental and theoretical results of a comprehensive and first of its kind study on the kinetics of carbon dioxide (CO 2) absorption and desorption in and from aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), methyl-diethanolamine (MDEA) and 2-amino-2-methyl-1-propanol (AMP) and their mixtures (i.e., MEA + AMP , MEA + MDEA , DEA + AMP and DEA + MDEA ). Part-1 of this paper presents a detailed design of the novel hemispherical apparatus and a rigorous mathematical model applicable to both absorption and desorption conditions with some preliminary results and Part-2 provides detailed results with estimates of kinetic coefficients for CO 2 absorption and desorption for eight different aqueous amine systems. The new hemispherical contactor consists of a 76 mm diameter solid hemisphere housed in a Pyrex glass cylinder with appropriate gas and liquid feed and withdrawal systems. The liquid feed passes through a 4 mm ID tube, which is located in the center of the hemisphere, and discharges at the top. The liquid descends as a well-defined liquid film over the surface of the hemisphere and is collected by a funnel (79 mm ID) at the base of the hemisphere. The interfacial area and hydrodynamics are well defined and the entrance/exit effects as well as surface rippling are minimized. Using this apparatus, the absorption experiments were conducted at near atmospheric pressure with pure CO 2 saturated with water vapor at 293–323 K with initially unloaded solutions and the desorption experiments were performed at 333–383 K for CO 2 loadings between 0.02 and 0.7 moles of CO 2 per mole of amine using humidified nitrogen gas as a stripping medium at total system pressures up to 205 kPa. The new rigorous mathematical model developed to interpret the rate data is based on the principle of diffusional mass transfer accompanied with liquid-phase chemical reactions over a hemispherical liquid film. Also developed in this work is a methodology that uses the rigorous model in conjunction with a non-linear regression technique to estimate kinetic parameters. Preliminary results presented in this part of the paper show that the new experimental apparatus was successful in accurately measuring and the new model and its numerical implementation were successful in accurately predicting both absorption and desorption rates for all aqueous amine systems considered in this study.

Kinetics of carbon dioxide absorption and desorption in aqueous alkanolamine solutions using a novel hemispherical contactor—II: Experimental results and parameter estimation

In Part 1 of this paper, detailed design of the hemispherical apparatus and a rigorous mathematical model applied to CO 2 absorption and desorption in and from aqueous alkanolamine solutions was presented with some preliminary results. This part of the paper provides detailed results on CO 2 –amine kinetics under absorption and desorption conditions and present new estimates of the kinetic parameter for aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), methyl-diethanolamine (MDEA) and 2-amino-2-methyl-1-propanol (AMP). The absorption experiments were conducted at near atmospheric pressure with pure humidified CO 2 at 293–323 K using initially unloaded solutions. The desorption experiments were performed at 333–383 K for CO 2 loadings between 0.02 to 0.7 mol of CO 2 per mole of amine using humidified nitrogen gas as a stripping medium at total system pressure ranging from 110 to 205 kPa. The new rigorous mathematical model discussed in Part 1 was used in conjunction with a non-linear regression technique to estimate the kinetic parameters. In all cases, the new model predicts the experimental results well. Also, the new results clearly demonstrate that the theory of absorption with reversible chemical reaction could be used to predict desorption rates. The zwitterion mechanism adequately describes the reactions between CO 2 and carbamate forming amines such as MEA, DEA and AMP. The reactions between CO 2 and aqueous MDEA solutions are best described by a base-catalyzed hydration reaction mechanism. The kinetic data obtained show that desorption experiments could be used to determine both forward and backward rate constants accurately. The absorption experiments, on the other hand, could only be used to determine forward rate constants. It was found that at all operating conditions used in this study, the kinetic parameters for MEA, DEA and AMP obtained using absorption data could not be extrapolated to predict desorption rates. However, for MDEA, these data could be used successfully to obtain reasonably good predictions of desorption rates.

DEGRADATION OF AQUEOUS SOLUTIONS OF ALKANOLAMINE BLENDS AT HIGH TEMPERATURE, UNDER THE PRESENCE OF CO2 AND H2S

ABSTRACT An experimental study on the degradation of aqueous solutions of alkanolamine blends, under the presence of carbon dioxide and hydrogen sulfide, was carried out. The studied alkanolamines were: diethanolamine (DEA), methyldiethanolamine (MDEA), and 2-amino-2-methyl-1-propanol (AMP). Degradation experiments were carried out at a temperature of 200°C. The mass fraction of DEA and MDEA in the studied aqueous solutions was 10% and 35%, respectively. AMP was incorporated into the MDEA-DEA aqueous solutions, with concentrations of (0–8) mass fraction. Partially degraded alkanolamine aqueous solutions were analyzed, after about 90 hours, by gas chromatography. It was found that in all the studied alkanolamine aqueous solutions the MDEA degrades more slowly than DEA under the same experimental conditions. Degradation of both alkanolamines was found to be almost independent of the AMP concentration. AMP exhibits an intermediate stability; it is more resistant to degradation than DEA but less than MDEA. In addition, thermal degradation of DEA and MDEA is minimal up to 200°C.

Using polypropylene and polytetrafluoroethylene membranes in a membrane contactor for CO 2 absorption

Over the past 20 years, gas absorption membrane (GAM) contactors have been evaluated as an alternative to packed columns in carbon dioxide (CO 2) capture applications. The success of this technology is highly dependent on the wetting relationship between the membrane and liquid solvent used in the system. This paper tests the performance of microporous polypropylene (PP) and polytetrafluoroethylene (PTFE) hollow fiber membranes in a GAM system using aqueous solutions of monoethanolamine (MEA) and 2-amino-2-methyl-1-propanol (AMP). Experimental results showed that PP membranes suffer a loss in performance over time when used with aqueous alkanolamine solutions, while PTFE membranes maintain their initial level of performance. A new GAM module design allowed for the connection of modules in series, intermediate data sampling points, and removable membrane cartridges. Overall, GAM systems were shown to be an effective technology for absorbing CO 2 from simulated flue gas streams, but the solvent–membrane relationship is a critical factor that can significantly affect system performance.