e-NRTL Model Research Articles

Comparison of liquid–liquid phase equilibrium behavior of acetonitrile–water system using choline chloride salt and water-based deep eutectic solvent

The liquid–liquid equilibrium (LLE) data for the ternary systems of (acetonitrile (ACN) + water (W) + choline chloride (ChCl)) and (ACN + W + water-based deep eutectic solvent (WDES) consisting of ChCl:W (1:3)) were measured at 298 K. The consistency of tie-lines was verified by the Bachman and Othmer-Tobias correlations. ChCl as an organic salt and its WDES (within the water content range of less than 50 w%) as green extractants represent feasible performances in terms of selectivity and distribution coefficients for separation of water from acetonitrile-water system in comparison to other inorganic salts and hydrophobic DESs. ChCl in the (ACN + W + ChCl) system can separate water from the solution in the form of hydrate ions while WDES in the (ACN + W + WDES) system tends to absorb water by intermolecular forces. The experimental data of the (ACN + W + ChCl) system was correlated using the symmetric electrolyte non-random two liquid (e-NRTL) model while the equilibrium data of the (ACN + W + WDES) system was correlated using NRTL and universal quasi-chemical activity coefficient (UNIQUAC) models. ChCl in the form of salt represents a better separation performance than WDES for water removal from the acetonitrile mixture. Meanwhile, WDES might be considered to be superior compared to ChCl in terms of regeneration energy consumption and operating considerations.

Comparative study of deterministic and stochastic optimization algorithms applied to the absorption of CO2 by alkanolamine solution

Abstract A model based on simulated annealing approach is used with e-UNIQUAC model as well as two other algorithms to study the absorption of carbon dioxide by monoethanolamine solutions. In this work, we propose to compare the performance (through the knowledge of RMSD values) of two stochastic methods, namely the GA (genetic algorithm) and SA (simulated annealing) methods and a deterministic method that is the simplex method. These methods were applied to the absorption of carbon dioxide by an alkanolamine solution using a chemical equilibrium model and a thermodynamic equilibrium model. The latter is based on the use of the modified-UNIQUAC (UNIQUAC-electrolyte) model instead of e-NRTL model for the liquid phase and a fugacity model for the vapor phase. The chemical equilibrium in this work represents the absorption of CO2 by monoethanolamine solution at different temperatures. Solving the coupled system of material and charge balances gives us the carbon dioxide pressure while taking into account the non-ideality of the system. The three-optimization methods show good agreement with the experimental data with a better performance of the simulated annealing method..

Effect of protic surfactant ionic liquids based on ethanolamines on solubility of acetaminophen at several temperatures: measurement and thermodynamic correlation

Absolute qualifications with the application of protic ionic liquids (PILs) and a recognition of the numerous thermophysical features of these materials are required in various processes. Due to the wonderful applications of these compounds and their high potential in the chemical and pharmaceutical industries, there is a particular eagerness to utilize these PILs in drug solubility and delivery area. The aim of this investigation was to explore the solubility of the acetaminophen (ACP) in three PILs base on ethanolamine laurate [(2-hydroxyethylammonium laurate [MEA]La), (bis(2-hydroxyethyl)ammonium laurate [DEA]La), and ( tris(2-hydroxyethyl)ammonium laurate [TEA]La)]. The shake flask method has been employed in this study, and the conditions were set at T = (298.15–313.15) K and atmospheric pressure. Moreover, the experimental solubility data was correlated using a variety of empirical and thermodynamic models, encompassing e-NRTL and Wilson activity coefficient models and the empirical models such as Van’t Hoff-Jouyban-Acree and Modified Apelblat-Jouyban-Acree. Their performance for the system containing [MEA]La follow the trend for activity coefficient models and empirical respectively: the Wilson > e-NRTL and Modified Apelblat–Jouyban–Acree > Van’t Hoff–Jouyban–Acree. On the other hand, [DEA]La and [TEA]La PILs followed slightly different trend for activity coefficient models and empirical respectively: the Wilson > e-NRTL and Van’t Hoff–uyban–Acree > Modified Apelblat–Jouyban–Acree. The Van’t Hoff and Gibbs equations were used to determine the thermodynamic properties of dissolution in the studied systems.

Modeling gas–liquid equilibrium of carbon dioxide in mixtures of (1-butyl-3-methyl-imidazolium acetate + 1-(2-aminoethyl) piperazine + water) and (1-butyl-3-methyl-imidazolium acetate + bis (3-aminopropyl) amine + water) by electrolyte non-random two liquid (e-NRTL) model

Targeting the control in emissions of post-combustion carbon dioxide capture from large point sources, a simulation approach towards the estimation of important thermodynamic property parameters useful in designing of carbon capture and sequestration technologies is being proposed. In the current work, simulation is carried out for modeling the gas – liquid equilibrium of CO2 in two aqueous mixtures of ionic liquid 1-butyl-3-methyl imidazolium acetate ([bmim][Ac]) and amines viz. ([bmim][Ac] + 1-(2-aminoethyl) piperazine) (AEP) and ([bmim][Ac] + bis (3-aminopropyl) amine) (APA). The experimental CO2 solubilities were taken from our previously published work and is regressed with electrolyte–Non-Random Two Liquid (e-NRTL) model for the liquid phase while Redlich-Kwong (RK) equations of state (EOS) was used to model the gas phase. Various thermodynamic parameters of importance and concentration of species in the mixtures were regressed in the model using Aspen Plus 14.

Modeling H2S solubility in aqueous MDEA, MEA and DEA solutions by the electrolyte SRK-CPA EOS

In this study, an electrolyte cubic plus association equation of state (e-CPA EOS) has been proposed to predict the vapor–liquid equilibrium of (H2S) in aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA). This EOS is composed of repulsive forces, short-range interactions, short-range ionic interactions, association term, long-range ionic interactions, and Born term. The Soave– Redlich– Kwong EOS is used as a non-electrolyte part. A new iterative procedure based on the Jacobi method is introduced to obtain the compositions of all species in the liquid phase. The genetic algorithm (GA) is used to find the optimal values of binary interaction coefficients between molecules and ions. Compared with experimental data, the e-CPA EOS model successfully describes the vapor–liquid equilibrium of H2S in the aqueous solutions of MEA, DEA, and MDEA. The average absolute deviations for 313 data of MEA-H2S-H2O, 156 data of DEA-H2S-H2O, and 145 data of MDEA-H2S-H2O systems were obtained as 8.20 %, 8.04 %, and 9.41 %, respectively. In addition, for some similar cases, the capability of the e-CPA EOS was compared with the Clegg–Pitzer, N-Wilson-NRF, e-NRTL, and e-CTS models. The results indicated that the e-CPA EOS has less error than the four other models.

Liquid–Liquid Equilibria of the System Nitric Acid + Phosphoric Acid + Calcium Nitrate + Water + Tri-n-Octylamine at 298.15 K

Liquid–liquid equilibrium (LLE) data of the system nitric acid + phosphoric acid + calcium nitrate + water + tri-n-octylamine (TOA) were measured at 298.15 K and atmospheric pressure. The distribution coefficients of nitric acid, phosphoric acid, calcium nitrate, and water and the separation factors of nitric acid against phosphoric acid, nitric acid against calcium nitrate, and nitric acid against the water were calculated. Based on these data, the capability and selectivity of TOA for extracting nitric acid in this system were evaluated. The experimental results were used to obtain binary interaction parameters and pair parameters as correlated by the electrolyte non-random two-liquid (eNRTL) model. The eNRTL model was shown to be suitable for predicting the LLE data of this system, with a root-mean-square deviation of just 1.17%.

Prediction of the solid-liquid equilibrium of ternary and quaternary salt-water systems. Influence of the e-NRTL interaction parameters

The aim of this work is to use the refined binary electrolyte-solvent interaction parameters of the e-NRTL model obtained in a previous paper (J.L. Valverde et al. Fluid Phase Equilibria (2022), 551, 113264) and to analyse the impact of considering the electrolyte-electrolyte interaction parameters different from zero on the prediction of solid-liquid equilibria in salt-water mixtures. For this purpose, experimental data were fitted to the complete e-NRTL model by non-linear regression. Ternary (two salts + water) and quaternary (three salts + water) systems were considered. Almost all the systems analyzed were precisely predicted by using the e-NRTL model with the electrolyte-water pairs regressed previously and electrolyte-electrolyte ones set to zero. Including the electrolyte-electrolyte binary parameters in a proper way can slightly improve the solid-liquid equilibria prediction for some of the selected systems. The Na2SO4+K2SO4+Li2SO4+H2O mixture was described poorly than the remainder ones computed due to the complexity of the system which exhibits the formation of multiple salts.

Effect of mono, di, tri ethanolamine lactate ionic liquids on the solubility of acetaminophen: Experimental measurement and correlation

Solubility is one of the most important physicochemical properties in the discovery and development of drugs and adding a co-solvent to an aqueous solution for further designing drug formation is the most widely used method in the pharmaceutical industry. In recent years, protic ionic liquids (PILs) as a new low-cost and an environmentally friendly class of green solvents have been used to overcome drug solubility issues. In this research work, the effect of some PILs containing 2-hydroxyethylammonium, bis(2-hydroxyethyl)ammonium, and tris(2-hydroxyethyl)ammonium cations and lactate anion have been investigated for acetaminophen (ACP) solubility at temperature ranges (298.15 to 313.15) K. The results show that ACP solubility increases with increasing PIL concentration and at higher temperatures and that PILs containing tris(2-hydroxyethyl)ammonium lactate have a greater impact on ACP solubility. The obtained solubility data were fitted by the e-NRTL and Wilson models which e-NRTL model is more consistent with experimental data. Finally, by applying the Gibbs and van't Hoff equations, the apparent dissolution thermodynamic functions such as enthalpy, Gibbs free energy, and entropy have been estimated. The results indicate that ACP dissolution processes in the investigated systems are endothermic.

Estimating VLE behavior from SLE data in aqueous mixtures of choline chloride-sorbitol deep eutectic solvents: Experimental investigation and thermodynamic modeling using the e-NRTL model

Knowledge of solid–liquid equilibria (SLE) and vapor–liquid equilibria (VLE) for mixtures containing deep eutectic solvents (DESs) is of paramount importance. We have conducted experiments to obtain additional data for SLE systems and then used the e-NRTL model to predict the VLE behavior in mixtures of DESs comprised of choline chloride (ChCl), sorbitol (S), and water (W). The systems under investigation include three 2-component systems (S/W, ChCl/W, ChCl/S), and one 3-component system (DES/W) where the DES is obtained by mixing ChCl and S at a molar ratio of 1. Using the e-NRTL activity coefficient model, the adjusted binary interaction parameters of the proposed model are determined solely from the experimental SLE data obtained from this work and also those in the literature. There is an excellent agreement between the SLE solubility data and the e-NRTL results. The tuned model is then used to predict the bubble pressure in three aqueous systems (S/W, ChCl/W, and DES/W) with an overall AARD value of 2.21%. The excellent agreement between the experimental and predicted VLE data demonstrates the viability of the proposed thermodynamic modelling framework to represent the equilibrium systems containing DESs. The outcome from our study can be used to relate the SLE and VLE data without the need to perform experiments for both cases for the given system of interest. Compared to the VLE experiments, the SLE tests are much simpler and safer because there is little compressibility and the effect of pressure on solubility is minimal which makes it possible to conduct SLE tests at room conditions (at least for liquids with negligible non-ideality). Therefore, conducting the high-pressure VLE calculations without the need to perform VLE experiments and through SLE experimental data alone will be of practical significance.

Energy and exergy analysis of multi-stage vacuum membrane distillation integrated with mechanical vapor compression

Membrane distillation (MD) is a promising candidate for desalinating hypersaline brine, but its poor energy efficiency has remained a major barrier for widespread application. One possible solution to this issue is to recover the latent heat in the process. In this work, a multi-stage vacuum MD (MSVMD) was integrated with a mechanical vapor compressor (MVC) to enhance the latent heat recovery, and the energetic and exergetic performance of this integrated process was examined. A comprehensive energy and exergy analysis is provided to compare MSVMD and MSVMD-MVC processes for desalination of hypersaline brine. This analysis was conducted by examining the effect of the compression ratio on the energetic and exergetic performance, and the findings are reported in terms of specific thermal energy consumption (STEC), specific electricity consumption (SEC), and exergetic efficiency. The energy analysis shows that thermal energy consumption can be reduced as the compression ratio increases, due to the enhancement of latent heat recovery. The MSVMD-MVC process can be operated in a steady-state condition, without the need for thermal heat input; with STEC and SEC of 0 and 49 kWh/m3 at the feed temperature of 50 °C and MVC compression ratio of 2.14. Moreover, exergy analysis demonstrates the efficacy of the eNRTL model in exergy calculation. Exergy destruction can be greatly reduced by increasing the compression ratio to an optimal value. For high salinity brine (124 g/L), MSVMD-MVC achieved a higher exergetic efficiency of 6.85%, compared to 2.42% in MSVMD. The result suggests that the application of MVC can intensify the energy efficiency and exergetic efficiency of the MSVMD system, although this process cannot outperform the current desalination technologies from the standard primary energy point of view.

Modeling and experimental measurement of NaBr solubility in water, methanol, ethanol, 1-propanol, and its mixtures at different temperatures

This work reports experimental data of NaBr solubility measured in water, methanol, 1-propanol, and mixed solvents water + ethanol, 1-propanol + methanol, and water + 1-propanol + methanol solvents at temperatures ranging from 283.15 K to 343.15 K. The effect of temperature on the solid–liquid-liquid equilibrium of the ternary system water + 1-propanol + NaBr was also studied, and it was found that the increase in temperature caused an increase in the immiscibility region of the system. The new solubility and phase equilibrium data measured in this work, as well as experimental information from the literature, were used to estimate the interaction parameters of the e-NRTL model, which combines the original Electrolyte Nonrandom Two-Liquid (NRTL) with a Pitzer–Debye–Huckel expression to consider the long-range interactions. Although the model overestimated the size of the liquid-liquid equilibrium regions for the water + 1-propanol + NaBr system, it adequately fit all the experimental solubility data.

A Benchmark Database for Mixed-Solvent Electrolyte Solutions: Consistency Analysis Using E-NRTL

Modeling of thermodynamic properties of mixed-solvent electrolyte solutions is challenging. Reliable experimental data are essential for any model development and parametrization. In this work, a benchmark database for (water + methanol/ethanol + alkali halide) mixed-solvent electrolyte solutions is presented. The available experimental data of mean ionic activity coefficient (MIAC) and vapor–liquid equilibrium (VLE) are comprehensively collected and critically evaluated for 61 data sets of 23 solutions. The resulting benchmark database includes 1413 data records from 32 data sets for 13 solutions. The evaluated data sets of the relevant aqueous electrolyte solutions are also presented. A consistent E-NRTL model that satisfies the Gibbs–Duhem equation is utilized for analyzing the data, reconciling the MIAC and VLE data. Based on the database, recommended parameters are obtained for the E-NRTL model.

The Split Flow Process of CO2 Capture with Aqueous Ammonia Using the eNRTL Model

Carbon Capture and Storage (CCS) technology has attracted increasing attention as global climate change accelerates. Carbon dioxide removal processes under development include pressure swing adsorption (PSA) and chemical absorption using amine solvents. In this paper, an ammonia solvent, which is relatively inexpensive and has good material properties, was used instead of amines in the carbon dioxide removal process simulation as a chemical absorption method. This simulation used the eNRTL thermodynamics model which has the advantage of predicting ions in the liquid phase in Aspen Plus. A case study (Case Study 1) was conducted to verify the validity of the thermodynamic model. The purpose of this research was to find the operating conditions to eliminate more than 90% of the carbon dioxide contained in the flue gas from coal-fired power stations, and to lower heat duty and operating cost conditions. A second case study (Case Study 2) was conducted to find the operating conditions by comparing various process operating conditions. Additionally, this paper determined lower operating cost conditions by manipulating the amount of steam and cooling water. The results showed that the heater’s outlet temperature should be set at under 80 ℃ to lower the operating costs. As a result of changing the flow rate of the side stream of the split flow process, energy consumption was reduced when compared to the conventional flow process. It was shown that the split flow is a superior process with 10.24% less energy use than the conventional flow. In this study, the split flow process achieved an energy saving advantage when compared to the conventional flow process, and a carbon dioxide removal rate of 95% was achieved.

CO2 and H2S absorption in aqueous MDEA with ethylene glycol: Electrolyte NRTL, rate-based process model and pilot plant experimental validation

Acid gas absorption with aqueous amines is an important industrial technology for natural or flue gas treatment. To lower the high energy required for the regeneration process it has previously been proposed to replace a significant part of the water by a physical co-solvent with a lower specific heat. To investigate this idea, as well as the overall impact of adding a physical co-solvent, a detailed process model for CO2 and H2S absorption using an aqueous mixture of N-methyl diethanolamine (MDEA) – ethylene glycol (EG) is developed based on lab-scale experimental measurements of physical, thermodynamic, and kinetic properties. Those experiments indicate that the addition of EG reduces the solubility of the acid gases and that, despite the higher viscosity of the solvent, the impact on the rate of acid gas absorption is minor. Pilot plant tests further confirmed this. The vapor-liquid equilibrium (VLE) experiments were used to regress the thermodynamic electrolyte e-NRTL (Non-Random Two-Liquid) model parameters. In parallel, the kinetic measurements allowed to develop a rate-based model. All models were implemented in a commercial process simulator that was validated with high-pressure absorption–regeneration pilot tests with the solvent composition of 34 wt% MDEA, 44.5 wt% EG and 21.5 wt% H2O and with the raw gas composition of 2.5 mol% H2S and 2.5 mol% CO2. Comparison with aqueous MDEA (50 wt% MDEA, and 50 wt% H2O) shows that a reduction of 25 % in reboiler duty can be obtained when adding EG. Nevertheless, an 80 % increase in solvent flow rate is needed to get a similar acid gas absorption performance, and a higher co-absorption of hydrocarbons is observed.

Vapor pressure measurement of electrolyte solution and its impact on regeneration process in TRAB

As a rapidly developing heat-electricity conversion technology in recent years, thermally regenerative ammonia-based battery (TRAB) is characterized with the advantages of high power density and recyclability. Compared with the chemical reaction in TRAB, the thermophysical properties of battery electrolyte is lack of investigation. In this paper, the vapor pressures of a typical TRAB electrolyte, CuSO 4 -(NH 4 ) 2 SO 4 –NH 3 –H 2 O, were measured from 333.15 K to 373.15 K. The common-used e-NRTL model was applied to fit the experimental data and describe the vapor-liquid equilibrium property of solution, with maximal relative deviation of 1.98% and average absolute relative deviation (AARD) of 0.66%. Thereafter, the regeneration requirement of TRAB was analyzed. The regeneration temperature is mainly influenced by regeneration pressure and Cu 2+ concentration, while NH 3 concentration shows insensitive effect on the regeneration temperature. To avoid too low regeneration pressure, the regeneration temperature needs to be higher than 94 °C with regeneration pressure higher than 80 kPa. Through the results obtained in this paper, persuasive reference can be provided for the prediction or simulation on the working process of TRAB. The results in this paper will contribute to the follow-up studies on the regeneration process of TRAB, especially the achievement of recycling of ammonia. • Experimental measurement of vapor pressure of CuSO 4 -(NH 4 ) 2 SO 4 –NH 3 –H 2 O is carried out from 333.15K to 373.15K. • The experimental results are integrated with literature data and correlated using e-NRTL model. • Regeneration requirement for TRAB is simulated with parametric analyses. • For the electrolyte investigated, the regeneration temperature is recommended to be higher than 94 °C.

Thermodynamic analysis of H2O − 3-aminopropyl tributyl phosphonium glycinate as a working pair for absorption refrigeration system

In this paper, A hydrophilic dual amino-functionalized ionic liquid 3-aminopropyl tributyl phosphonium glycinate ([aP4443][Gly]) with high thermal stability was used as absorbent and the refrigerant was water for the absorption refrigeration system (ARS). The heat capacities of the system were estimated by the differential scanning calorimetry (DSC) with various water mass fractions (w1) (0.004 to 0.6993) and temperatures (285 K to 365 K), and a polynomial equation on temperature and mass fraction of ionic liquid (w2) was associated. Between the experimental and estimated values, the average relative deviation (ARD) was 0.66%. The vapor–liquid equilibrium (VLE) data of the H2O–[aP4443][Gly] binary mixture was correlated using the electrolyte nonrandom two-liquid (eNRTL) model, and the binary mixture's excess thermodynamic properties were simulated. The first and second laws of thermodynamics were used to simulate the performance of a single-effect ARS with a solution heat exchanger (SHE). The ARS simulation results show that the coefficient of performance (COP) of the system with H2O–[aP4443][Gly] as the working pair is higher than that of the conventional working pair NH3-H2O but slightly lower than that of H2O-LiBr. Furthermore, the effect of generator temperature (Tg) on ARS is investigated; simulation results show that the ARS of the novel working pair has a higher COP value at higher generator temperature, indicating that H2O–[aP4443][Gly] has the potential to be a new type of absorption refrigeration working pair.

Application of the e-NRTL model to electrolytes in mixed solvents methanol-, ethanol- water, and PEG-water

In this work, the e-NRTL binary interaction parameters for the alcohol-water (ethanol-water and methanol-water), electrolyte-alcohol (NaBr-methanol, NaBr-ethanol, NaCl-methanol, NaCl-ethanol, KCl-methanol and KCl-ethanol), PEG (polyethylene glycol)-water (PEG1000-, PEG4000- and PEG6000-water) and electrolyte-PEG (NaCl and KCl-PEG4000-water, KCl-PEG1000-water, LiCl-PEG4000-Water, CsCl-PEG (PEG1000, PEG4000 and PEG 6000)-Water) were evaluated by the non-linear regression of experimental data at different temperatures, reported in the literature. The application used was able to evaluate the impact of the NRTL, Debye-Hückel and Born contributions on the activity coefficients of a salt (or an electrolyte) in different media. In addition, the solubility constants, and the free energy of transfer on the molar scale of NaCl, KCl and NaBr in alcohol-water mixed solvents (methanol-water and ethanol-water at different temperatures) were evaluated by using the e-NRTL model and the binary interaction parameters previously computed. It was reached an excellent correlation of the experimental data of water activity, mean activity coefficient and osmotic pressure data of ethanol-water and methanol-water solutions, electrolyte-alcohol systems, and electrolyte-PEG, respectively. The presence of PEG and alcohol in solution had a great influence on the solubility of the solid phases.

Influence of choline-based ionic liquids as neoteric green solvents on aqueous solubility of lamotrigine and piroxicam drugs

Background: The low aqueous solubility of three important drugs (betamethasone (BETA), meloxicam (MEL) and piroxicam (PIR)) have been increased by use of deep eutectic solvents (DESs) based choline chloride/urea (ChCl/U), choline chloride/ethylene glycol (ChCl/EG) and choline chloride/glycerol (ChCl/G) as new class of solvents at T = (298.15 to 313.15) K. Methods: DESs were prepared by combination of the ChCl/EG, U and G with the molar ratios: 1:2. The solubility of drugs in the aqueous DESs solutions was measured at different temperatures with shake flask method. Results: The solubility of the investigated drugs increased with increasing the weight fraction of DESs. The solubility data were correlated by e-NRTL and Wilson models. Also, the thermodynamic functions, Gibbs energy, enthalpy, and entropy of dissolution were calculated. Conclusion: At the same composition of co-solvents and temperature, the BETA, PIR and MEL solubility was highest in (ChCl/U + water), (ChCl/U + water) and (ChCl/EG + water) respectively. The calculated solubility based on these models was in good agreement with the experimental values. In addition, the results show that, the main contribution for drugs solubility in the aqueous DES solutions is the enthalpy.

Estimation of e-NRTL binary interaction parameters and its impact on the prediction of thermodynamic properties of multicomponent electrolyte systems

The main objective of the current work is to obtain and validate the binary interaction parameters of the e-NRTL model for different salts in water, using the data of mean ionic activity coefficients vs. molality compiled by Robinson and Stokes (Electrolyte Solutions, Dover Publications, 2012). This way, the interaction parameters τsalt,water and τwater,salt of the e-NRTL thermodynamic model for 171 binary (salt + water) electrolyte systems have been calculated by non-linear regression of the data available in the literature. The fitting was performed by the Marquardt-Levenberg algorithm which was computationally implemented in an Excel VBA homemade program. The e-NRTL equation was solved by using two different procedures: (i) included in the Excel VBA code or, (ii) implemented in Aspen Plus by linking the process simulator and the Excel VBA code via automation as the third-party software. The interaction parameters obtained by both approaches were able to adequately fit the experimental results. They were successfully validated by the thermodynamic prediction of multicomponent systems reported by other authors. Additionally, the current predictions were compared with those obtained with the parameters contained in the Aspen Properties database showing a significant improvement for several systems. Finally, this work demonstrates that it is possible enhancing the quality of the prediction of multicomponent systems with proper values of the binary electrolyte interaction parameters, without considering electrolyte-electrolyte interactions foreseen in the original e-NRTL model, which makes possible the simulation of processes containing a variety of chemical species regardless their nature.

New solubility and heat of absorption data for CO2 in blends of 2-amino-2-methyl-1-propanol (AMP) and Piperazine (PZ) and a new eNRTL model representation

New data comprising CO2 partial pressure, total pressure, and the heat of absorption of CO2 for over aqueous solution of 3 mol/dm3 AMP and 1.5 mol/dm3 PZ and total pressure and heat of absorption for different mol ratios of AMP/PZ (3.0/0.0, 0.0/1.5, 0.5/4.0, 1.5/3.0, 2.25/2.25, 3.0/1.5, 4.0/0.5) are presented as functions of CO2 loading and temperature.Measured solubility data and selected data reported in the literature were used in the regression of binary interaction energy parameters in the quaternary system (AMP/PZ/H2O/CO2) using the eNRTL model. The equilibrium constants and binary interaction energy parameters from our previous work on the ternary systems of AMP/H2O/CO2 and PZ/H2O/CO2 were used without refitting.Good agreement with the literature was observed for the total pressure data over aqueous solutions of 3.0 mol/dm3 AMP and 1.5 mol/dm3 PZ, and the CO2 partial pressure and heat of reaction data over aqueous solutions of 3.0 mol/dm3 AMP+1.5 mol/dm3 PZ at different loadings and temperatures. The results reflect that the new data are consistent with reported data from the literature.The modeling results show that the eNRTL model represents the data well with AARD values of 13.1% for total pressure and 20.9% for CO2 partial pressure. The volatility of AMP and PZ as function of loading and temperature and published speciation data for AMP/AMPH+, PZ/PZH+/PZH22+, PZCO2−/PZH+CO2−, PZ(CO2−)2 and HCO3−/CO32− were also well predicted.Only the heat of absorption data over an aqueous solution of 3.0M AMP+1.5M PZ from this work can be compared with literature data, and good agreement is observed. The eNRTL model also predicts satisfactorily the experimentally obtained heat of absorption data for all different ratios of AMP/PZ. Individual reaction contributions show that when the AMP/PZ ratio increases, the predicted total heat of absorption goes toward the single solvent AMP system where only protonated AMP is the main contributor. When the AMP/PZ ratio decreases, the predicted total heat of absorption also approaches the single solvent PZ system where the protonated PZ, PZ-monocarbamate and zwitterion reactions play important roles. In systems with high PZ-concentration, the contribution of the zwitterion, protonated PZ and PZ-carbamate cancel each other at high loadings.