Carbon dioxide loading capacity in aqueous solution of Potassium salt of Proline blended with Piperazine as new absorbents (original) (raw)
Related papers
Carbon dioxide absorption with aqueous potassium carbonate promoted by piperazine
Chemical Engineering Science, 2004
Many commercial processes for the removal of carbon dioxide from high-pressure gases use aqueous potassium carbonate systems promoted by secondary amines. This paper presents thermodynamic and kinetic data for aqueous potassium carbonate promoted by piperazine. Research has been performed at typical absorber conditions for the removal of CO2 from ue gas.
Mixture of piperazine and potassium carbonate to absorb CO2 in the packed column: Modelling study
Fuel, 2022
A rate-based non-equilibrium model is developed for CO2 absorption with the mixture of piperazine and potassium carbonate solution. The model is based on the mass and heat transfer between the liquid and the gas phases on each packed column segment. The thermodynamic equilibrium assumption (physical equilibrium) is considered only at the gas-liquid interface and chemical equilibrium is assumed in the liquid phase bulk. The calculated mass transfer coefficient from available correlations is corrected by the enhancement factor to account for the chemical reactions in the system. The Extended-UNIQUAC model is used to calculate the nonidealities related to the liquid phase, and the Soave-Redlich-Kwong (SRK) equation of state is used for the gas phase calculations. The thermodynamic analysis is also performed in this study. The enhancement factor is used to represent the effect of chemical reactions of the piperazine promoted potassium carbonate solution, which has not been considered given the rigorous electrolyte thermodynamics in the absorber. The developed model showed good agreement with the experimental data and similar studies in the literature.
Reactive Absorption of Carbon Dioxide in l-Prolinate Salt Solutions
Industrial & Engineering Chemistry Research, 2014
Aqueous amino acid salt solutions are seen as more sustainable alternative CO 2 solvents compared to conventional alkanolamines. The absorption of CO 2 into aqueous solutions of potassium L-prolinate, over the temperature range of 290−303 K, was studied using a stirred cell. To compare the effect of potassium versus sodium as counterion, the absorption rates of CO 2 in sodium L-prolinate solutions were also determined. The amino acid salt concentration was varied between 0.5 and 3 mol dm −3. Physicochemical properties such as density, viscosity, and physical solubility of N 2 O, required in the interpretation of absorption rate experiments, were determined separately. The obtained experimental reactive absorption fluxes were interpreted, using the pseudo-first-order approach, into intrinsic reaction kinetics. The potassium-based solvent showed, on average, a 32% higher reactivity toward CO 2 than the sodium equivalent. The kinetic data were correlated in a power-law reaction rate expression. The reaction order with respect to the amino acid was found to be between 1.40 and 1.44 for both L-prolinate salts, and the second order kinetic rate constant, k 2 , was calculated for the potassium salt to be 93.7 × 10 3 dm 3 •mol −1 •s −1 at 298 K with an activation energy of 43.3 kJ•mol −1. L-Prolinate salts show higher chemical reactivity toward CO 2 than most of the aminoalcohols and amino acid salts.
Chemical Engineering Research and Design, 2015
In this work, physical properties such as density, viscosity and refractive index of aqueous sodium L-prolinate (SP) and piperazine (PZ) as a solvent for CO 2 removal were measured at temperatures from 298.15 to 343.15 K at 5 K intervals. Different mass fractions (w 1 +w 2) % of aqueous blends of (SP+PZ) were 0.10+0.02, 0.10+0.05, 0.20+0.02, 0.20+0.05, 0.30+0.02, and 0.30+0.05. It was observed that the density, viscosity and refractive index increase with increasing the mass fraction, and decrease with increasing temperature. The density data were used for theoretical evaluation of thermal expansion coefficients. It was found that thermal expansion coefficient increases slightly with increasing concentration and temperature. Empirical correlations were applied to the measured physical properties in order to calculate the predicted data. The statistical error analysis was carried out, which showed good agreement between experimental and predicted data.
Kinetics of Carbon Dioxide Absorption into Aqueous Potassium Carbonate and Piperazine
Industrial & Engineering Chemistry Research, 2006
The absorption rate of CO 2 was measured in a wetted-wall column in 0.45-3.6 m piperazine (PZ) and 0.0-3.1 m potassium carbonate (K 2 CO 3 ) at 25-110°C. A rigorous kinetic model was used to model the data and interpret diffusivities and rate constants. The rate approaches second-order behavior with PZ and is highly dependent on other strong bases. In 1 M PZ, the overall rate constant is 102 000 s -1 , 20 times higher than in monoethanolamine. The activation energy is 35 kJ/mol, similar to other amine-CO 2 reactions. Rate constants for contributions of carbonate, PZ carbamate, and water to the rate were determined according to base catalysis theory. The addition of neutral salts to aqueous PZ increases the apparent rate constant. In 2.7 M NaCl/0.6 M PZ, the overall rate constant is increased by a factor of 7. Ionic strength effects were accounted for within the rigorous model of K + /PZ mixtures. The absorption rate in concentrated K + /PZ mixtures is up to 3 times faster than in 30 wt % monoethanolamine. At low temperatures and low CO 2 loadings, a pseudo-first-order approximation adequately represents the absorption rate. At high loadings, the reaction approaches instantaneous behavior but is still influenced by reaction kinetics. Under industrial conditions, gas film resistance may account for >80% of the total mass transfer resistance at low loadings.
High-pressure Solubility of Carbon Dioxide in Aqueous Sodium L- Prolinate Solution
Procedia Engineering, 2016
An experimental evaluation of CO 2 solubility in aqueous sodium L-prolinate (SP) solution was carried out using high-pressure solubility equipment at three different temperatures, 303.15, 313.15, and 333.15 K. The study was conducted over the pressure range from 2 to 60 bar for 30 wt. % SP solution. It was found that, the CO 2 loading (mole of CO 2 / mole of SP) decreases with increasing temperature, while it increases with increasing the pressure of gas. ANOVA analysis was carried out to determine the statistical significance of the solubility data with respect to temperature a nd pressure. The CO 2 loading of aqueous SP solution was also compared with MEA and aqueous sodium glycinate (SG) solution. It was observed that the aqueous SP solution has higher CO 2 loading capacity as compared to 30 wt. % MEA, and comparable with aqueous 30 wt. % SG solution.
Absorber intercooling in CO2absorption by piperazine-promoted potassium carbonate
AIChE Journal, 2009
Intercooling was evaluated as a process option in CO 2 absorption by piperazine (PZ) promoted potassium carbonate. The system performance with 4.5 m K þ /4.5 m PZ was simulated by a model in Aspen Plus V R RateSep TM. The absorber was evaluated for use with a double matrix stripper by optimizing the position of the semilean feed and intercooling stages to maximize CO 2 removal. Additionally, a simple absorber system was modeled to observe the effect of intercooling on systems with variable CO 2 lean loading. Intercooling increases CO 2 removal by as much as 10% with the double matrix configuration. With a simple absorber, the effectiveness of intercooling depends on solvent rate. Near a critical liquid/gas ratio (L/G) there is a large improvement with intercooling. This is related to the position of the temperature bulge. An approximation is proposed to estimate the critical L/G where intercooling may maximize removal. V
Carbon dioxide has a huge impact on the increase of greenhouse gas formation causing global warming and climate change. The most effective method to capture CO 2 is chemical absorption using potassium carbonate (K 2 CO 3) solution and amines as additive to enhance the absorption rate. CO 2 solubilities in 30% of K 2 CO 3 and 5% of the total composition of mixed methyldiethanolamine (MDEA)-diethanolamine (DEA) / piperazine (PZ)-DEA solutions at various temperatures of 303.15-323.15 K and atmospheric pressure are reported. The solubility data were measured using an equilibrium cell apparatus with the N 2 O analogy method. The E-NRTL model was used to correlate the experimental data accurately. The binary interaction parameters of the model for the CO 2-K 2 CO 3-MDEA-DEA-H 2 O and CO 2-K 2 CO 3-PZ-DEA-H 2 O systems were obtained. The CO 2 physical solubility in 30% of K 2 CO 3 , 5% of PZ, and 0% of DEA at 303.15 K had the highest value, while the Henry constant of CO 2 in this solution had the lowest value. The CO 2 loading increased with increasing partial pressure of CO 2 , while the CO 2 solubility decreased with increasing temperature. Any increase in MDEA concentration from 0% to 5% enhanced the CO 2 partial pressure, otherwise, an increase in PZ concentration from 0% to 5% decreased the CO 2 partial pressure.
High pressure solubility of carbon dioxide (CO2) in aqueous piperazine solutions
Fluid Phase Equilibria, 2010
The solubility of CO 2 in aqueous solutions of 1-methyl piperazine (1-MPZ) was measured at (313 and 353) K for (15 and 30) wt % and up to a pressure of 7815 kPa, reaching a gas loading of 0.67 mol CO 2 /mol alkalinity . The electrolyte−NRTL (nonrandom two-liquid) model was used to correlate the data. Five adjustable ionic pair interaction parameters and six molecular interaction parameters were regressed, which allowed for the correlation of the experimental solubility data within an average deviation of 2 % in pressure and temperature and 7 % in experimental loading. The model was used to predict the speciation, heat of absorption, and pH of the loaded solutions. The predicted properties were compared with PZ to show the advantages in using piperazine derivatives in CO 2 capture.