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Triethylene glycol (TEG) is widely used in the gas dehydration process. While absorbing water from the gas, some hydrocarbons may also be absorbed. Knowledge of hydrocarbon solubility in TEG is nec...

Energy shortage and environmental pollution are among the most serious challenges facing mankind. The utilization of efficient and green solvents has great urgency, if true action is to be taken to alleviate these issues. The Deep Eutectic Solvents (DESs) were recently introduced as sustainable solvents with special characteristics. These novel solvents have very low vapor pressures and can be “designed” for desired properties through the engineered selection of appropriate hydrogen-bond donors and acceptors. Research is necessary to investigate the feasibility of applying DESs in various industrial applications, including absorption refrigeration systems. Since the coefficient of performance (COP) and the exergetic coefficient of performance (ECOP) of an absorption refrigeration system depend highly on the properties of the absorbent and refrigerant, selecting a proper DES with particular attention to its physical properties, can dramatically affect its efficiency. In this study, three DESs were investigated as potential absorbents, consisting of Reline (1 Choline chloride + 2 urea), Ethaline (1 Choline chloride + 2 ethylene glycol) and Glyceline (1 Choline chloride + 2 glycerol), with ammonia as the refrigerant. A modified SRK-NRTL model was used to estimate the physical and thermodynamic properties of the DESs and their mixtures with ammonia. The COPs and ECOPs of the absorption refrigeration cycles were calculated within wide ranges of absorber and regenerator temperatures. The results were compared to literature systems, including ammonia/water and ammonia/ionic liquids cycles. The performances based on energy and exergy analyses showed that ammonia/DES working fluids have the potential to be used in such cycles.

Cyclohexanone is largely generated in the direct or indirect conversion of lignin-derived bio-oils. Hence, the upgrading of cyclohexanone, i.e. deoxygenation in the presence of hydrogen is of great interest. In this regard, two nickel-molybdenum catalysts on alumina support were investigated in the temperatures up to 400 °C and pressures up to 15 bar. High activity, selectivity, and yield were achieved by utilizing these catalysts at the studied condition. The main products of the upgrading of cyclohexanone were C6, C7, and C12 cyclic, aromatic, and bicyclic including cyclohexane, cyclohexene, benzene, and cyclohexylbenzene. The results of the present study imply that these catalysts are beneficial in producing hydrocarbon-rich products from cyclohexanone and lignin-derived bio-oils. Based on the achievements of the present study, the nickel-molybdenum catalyst composed of 1.14 wt% nickel and 14.27 wt% molybdenum showed about 87%, 100%, and 116% conversion of cyclohexanone, total hydrocarbon selectivity, and total hydrocarbon yield, respectively. The optimum condition for obtaining such results was at 400 °C and 8 bar.

In this work, the selective separation of toluene from mixtures of toluene + heptane or toluene + hexane was investigated using the newly emerging family of solvents, namely, deep eutectic solvents...

The spent bleaching clay (SBC) from the edible oil refining industries contains different types of contaminants, including fatty acids and trace amounts of heavy metals and hazardous materials. Therefore, the conventional procedure of landfilling of SBC is not safe for the environment. Because of this, researchers have been trying to find alternative routes, such as novel processes to regenerate the clay and reuse it. The large amounts of oil remaining in SBC justifies the investigation of in-situ transesterification of the oil to biodiesel. In this study, clays that have been de-oiled by in-situ transesterification at various operating conditions are investigated for their final regenerated bleaching capacity. The different in-situ operating parameters considered are: the choice between two different alkali catalysts, catalyst/SBC ratio, ethanol/SBC ratio, temperature, and reaction time. With 60 different experiments and using the method of experimental design, the optimum operating parameters were determined and presented for achieving maximum bleaching capacity of the regenerated clay. The suggested conditions were then confirmed experimentally. Results showed that the maximum bleaching capacity at these optimum conditions was 17.03%.

Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. In this study, the viscosity behavior of two mixtures of Ethaline (1 ChCl:2 ethylene glycol) with either methanol or ethanol were investigated over the temperature range of 283.15–333.15 K at atmospheric pressure. The measured viscosities of neat Ethaline, methanol, and ethanol showed reliable agreement with the corresponding reported literature values. The mixture viscosities were modeled by an Arrhenius-like model to determine the behavior of viscosity with respect to temperature. The data were also modeled by the four well-known mixture viscosity models of Grunberg–Nissan, Jouyban–Acree, McAllister, and Preferential Solvation. All of the model results were reliable, with the Jouyban–Acree and Preferential Solvation models showing the most accurate agreement with the experimental measurements. The Jones–Dole viscosity model was also investigated for the measured viscosities, and by analyzing the results of this model, strong interactions among Ethaline and the alcohol molecules were proposed for both systems. As a final analysis, viscosity deviations of the investigated systems were calculated to study the deviations of the viscosity behaviors with respect to ideal behavior. Both systems showed negative viscosity deviations at all of the investigated temperatures, with the negative values tending towards zero, and hence more ideal behavior, with increasing temperatures. Moreover, in order to correlate the calculated viscosity deviations, the Redlich–Kister model was successfully used for both systems and at each investigated temperature. publishersversion published

The urgency of advancing green chemistry from labs and computers into the industries is well-known. The Deep Eutectic Solvents (DESs) are a promising category of novel green solvents which simultaneously have the best advantages of liquids and solids. Furthermore, they can be designed or engineered to have the characteristics desired for a given application. However, since they are rather new, there are no general models available to predict the properties of DESs without requiring other properties as input. This is particularly a setback when screening is required for feasibility studies, since a vast number of DESs are envisioned. For the first time, this study presents five group contribution (GC) and five atomic contribution (AC) models for densities, refractive indices, heat capacities, speeds of sound, and surface tensions of DESs. The models, developed using the most up-to-date databank of various types of DESs, simply decompose the molecular structure into a number of predefined groups or atoms. The resulting AARD% of densities, refractive indices, heat capacities, speeds of sound and surface tensions were, respectively, 1.44, 0.37, 3.26, 1.62, and 7.59% for the GC models, and 2.49, 1.03, 9.93, 4.52 and 7.80% for the AC models. Perhaps, even more importantly for designer solvents, is the predictive capability of the models, which was also shown to be highly reliable. Accordingly, very simple, yet highly accurate models are provided that are global for DESs and needless of any physical property information, making them useful predictive tools for a category of green solvents, which is only starting to show its potentials in green technology.

The spent bleaching clays (SBC) of vegetable oil refining plants have residual vegetable oil contents ranging from 17 to 40 wt%. The common worldwide practice of landfilling such spent clays imposes inevitable environmental hazards. The extraction of oil from a spent clay will not only alleviate this problem, but can also provide an oil source for processes, such as transesterification for the production of alcohol-esters. In-situ transesterification of the residual oil within SBC is an even more attractive idea, as it can eliminate the extraction step from the process. In this study, in-situ transesterification on the spent bleaching clay of a local vegetable oil plant was investigated experimentally. Furthermore, optimum operating conditions were determined for a number of parameters influencing the conversions, including reaction temperature, ethanol-to-SBC ratio, alkali catalyst type, and catalyst-to-SBC mass ratio. The experiments were designed by the response surface method based on the central composite approach (RSM-CCD model). The results were analyzed using the analysis of variance method (ANOVA) to investigate the effect of the parameters on the efficiencies of the biodiesel produced and the oil removed from the initial SBC. Within the ranges investigated, the maximum conversion to ethyl-ester was 72.90% at the optimum conditions of a reaction temperature of 73.2 °C, reaction time of 4.5 h, ethanol/SBC ratio of 4.2 ml/g, while using NaOH alkali catalyst with a catalyst-to-SBC mass ratio of 4.33%.

ERC-2016-CoG 725,034 UID/QUI/50006/2019 Deep eutectic solvents (DESs) are newly introduced green solvents that have attracted much attention regarding fundamentals and applications. Of the problems along the way of replacing a common solvent by a DES, is the lack of information on the thermophysical properties of DESs. This is even more accentuated by considering the dramatically growing number of DESs, being made by the combination of vast numbers of the constituting substances, and at their various molar ratios. The speed of sound is among the properties that can be used to estimate other important thermodynamic properties. In this work, a global and accurate model is proposed and used to estimate the speed of sound in 39 different DESs. This is the first general speed of sound model for DESs. The model does not require any thermodynamic properties other than the critical properties of the DESs, which are themselves calculated by group contribution methods, and in doing so, make the proposed method entirely independent of any experimental data as input. The results indicated that the average absolute relative deviation percentages (AARD%) of this model for 420 experimental data is only 5.4%. Accordingly, based on the achieved results, the proposed model can be used to predict the speeds of sound of DESs. publishersversion published

Deep Eutectic Solvents are complex solvents whose properties are challenging to understand and to model. In this study, the Prigogine–Flory–Patterson (PFP) theory was used, for the first time in literature, to estimate excess molar volumes of different systems consisting of Deep Eutectic Solvents (DESs). Twelve different systems, consisting of Ethaline + DMSO, Ethaline + water, Reline + water, Reline + methanol, Reline + ethanol, Glycine + water, Glycine + methanol, Glycine + ethanol, Glycine + isopropanol, Maline + water, Tegaline + water, and Glucoline + water were investigated in the full range of concentrations and within wide ranges of temperature, at atmospheric pressure. Excess molar volume is a complicated thermodynamic property because it depends not only on the shape, size, and chemical nature of each pure component in the mixture, but also on all of the binary and higher order interactions of the components in the mixture. The Prigogine–Flory–Patterson theory is one of the very few theoretical models for estimating excess molar volume. Because of the thermodynamic background of the PFP theory, which divides the excess molar volume into three different molecular interaction contributions, the results of this model in mixtures involving DESs can be valuable for a rough interpretation of the molecular interactions of such complex mixtures at a microscopic scale. In order to avoid the correlative aspect of the PFP theory, a generalized relation was proposed for the interaction parameter of the theory covering all temperatures. The resulting model, with a total AARD% of 14.6% and agreement between the predicted trends and the corresponding experimental trends, indicated the capability and suitability of the PFP theory in estimating excess molar volumes of such complex and non-ideal mixtures consisting of DESs.

Deep eutectic solvents (DESs), with their attractive properties, are currently of great interest. Introducing new kinds of eutectic solvents with different components as their hydrogen bond donors (HBD) and hydrogen bond acceptors (HBA), and investigating the (thermo-) physical properties of the new DESs can play an important role in promoting future research and use of such mixtures. In this study, we investigate the feasibility of the formation of new kinds of eutectic solvents based on the sodium halide salts as the hydrogen bond acceptors with ethylene glycol as the hydrogen bond donor. Different molar fractions of HBD/HBA were investigated. The results indicated that sodium fluoride does not form a DES throughout the whole concentration range investigated, while sodium chloride, sodium bromide, and sodium iodide do form eutectic mixtures at certain molar ratios. Differential scanning analysis was performed on the resulting eutectic solvents to measure the glass transition temperature. Other physical properties of the proposed DESs, namely density, viscosity, refractive index, and electric conductivity were also measured within the temperature range of 293–333 K. Furthermore, the effect of water in aqueous mixtures of the proposed DESs was investigated, with molar fractions of water ranging from 0.1 to 0.9. Based on the calculations of excess molar volume, the effect of water in the mixtures was investigated. Over the whole range of water concentrations in the mixture, the excess molar volumes had negative values, indicating intensive hydrogen-bonding between unlike molecules in the mixture and/or a void filling mechanism by the smaller molecules.

Deep Eutectic Solvents (DESs) have been introduced recently as a new generation of green solvents. DESs have great potential to be used in different fields and applications, and so, it is important to have information on the properties of DESs and their mixtures. Up to now, the volumetric properties of only aqueous mixtures of DESs have been investigated. In this study, we measured the densities of pseudo-binary mixtures of methanol and choline chloride + urea (1:2) (reline) at atmospheric pressure over the temperature range of 293.15–323.15 K. Based on the measured density data, excess molar volumes of the mixtures were calculated. All of the excess molar volumes had negative values, which show the stronger solvation interactions of the mixture molecules compared to the interactions within pure reline or methanol. Furthermore, the volumetric properties of partial molar volume, excess partial molar volume, partial molar volume at infinite dilution, excess partial molar volume at infinite dilution, and isobaric volume expansion were calculated. By comparing the excess partial molar volumes at infinite dilution of reline and methanol, it is concluded that each prefers to be surrounded by the other, and this tendency is stronger for reline molecules.

In this study, the deep eutectic solvent of choline chloride/urea, also known as Reline, was synthesized. Mixtures of Reline with ethanol were prepared covering the entire concentration range, and their densities were determined experimentally. Together with pure Reline and pure ethanol, this made a total of eleven systems, whose densities were measured over the temperature range of 293.15–333.15 K at pressure of 100 kPa. The volumetric properties of interest in the calculation of other derivative thermodynamic properties were determined for all of the investigated mixtures and temperatures. This included the correlation of density to temperature, as well as the excess molar volumes, partial molar volumes, partial molar volumes at infinite dilution, excess partial molar volumes, excess partial molar volumes at infinite dilution, and isobaric volume expansions. The excess molar volumes had negative values at all concentrations and temperatures. This led us to propose a possible molecular arrangement of the hydrogen bond network, placing Reline mainly in central positions, with the preference to be surrounded by ethanol molecules.

Deep eutectic solvents (DESs) make up a most-recent category of ‘green’ solvents with a potentially promising future. Insignificant vapor pressure, biodegradability, low cost, task-specific engineering, and high absorption for gases such as CO2 are the most important characteristics of most DESs. To apply DESs in various industries, knowledge of their physical properties is vital. Since the viscosity of a DES is a strong function of temperature, as well as the ratio of the hydrogen bond donating and accepting components, to estimate the viscosity behavior, a model based on sound theory is proposed in this study, i.e., the free volume theory. Since DESs are strongly associating components, this theory is enriched by using associating equations of state, namely CPA and PC-SAFT. In this study, a large density and viscosity databank of 27 DESs of different nature, also with varying molar ratios of the hydrogen bond donor and acceptor, were used to propose the model. In this way, a global model is presented for the first time to estimate the viscosities of DESs. The pseudo-component approach, with a 2B association scheme, was considered for the DESs. Both the CPA and the PC-SAFT EoSs, coupled with the free volume theory, showed reliable results, with average AARD% values in viscosity for all of the investigated DESs equal to 2.7% and 2.7%, respectively. Furthermore, both models reliably showed the trend of nearly logarithmic increase in DES viscosity with decreasing temperature. Also, both models accurately estimated the viscosity behavior of the DESs by not only changing the molecular nature of the hydrogen bond donor with a fixed hydrogen bond acceptor, but also at all of the various molar ratios investigated.

In this study, a new correlation is proposed for estimating 1-alkyl-3-methylimidazolium ionic liquid (IL) viscosities at different temperatures and atmospheric pressure. Since ILs are rather novel,...

In this study, the aqueous mixture viscosities of two phenolic DESs, consisting of (1 ChCl: 3 phenol) and (1 ChCl: 4 phenol), were measured at atmospheric pressure over the temperature range of 293.15 - 333.15 K. According to the measured data, the values of viscosity deviations for the investigated aqueous systems were calculated to indicate deviating viscosity behavior with respect to ideality. Both aqueous systems showed negative viscosity deviations over the entire composition range and at all of the investigated temperatures. The Redlich-Kister model was applied to estimate the viscosity deviations of both aqueous systems at different compositions and temperatures, while the viscosity behavior, itself, was modeled by different literature models, consisting of the Grunberg-Nissan, Jouyban-Acree, McAllister, Preferential Solvation, and an Arrhenius-like viscosity model. All of the models presented satisfactory agreement, however the Preferential Solvation and the Jouyban-Acree models succeeded to achieve more reliable results as compared to the others. In addition to the mixture viscosity estimation models, the Jones-Dole viscosity model was applied to both of the aqueous systems to suggest the interactions in the mixture. By calculating and analyzing the values of the B-coefficients of this model, possibly stronger interactions among the DESs and water molecules in the mixture were suggested, as compared to the self-species interactions.

Ionic liquids are considered as new absorbents with high solubility for separation of CO2 from flue gases. In this study, the effect of an ionic liquid ([Bmim][BF4]) on the absorption of CO2 using polypropylene hollow fiber membrane contactors was studied. Aqueous solutions of ionic liquid and mixture of ionic liquid with methyldiethanolamine were applied as physical and chemical absorbents, respectively. The effects of different parameters including concentration of ionic liquid in water and aqueous solution of methyldiethanolamine as base fluids, liquid and gas flow rates, and flow direction were investigated. The results showed that a 25 wt% solution of ionic liquid can increase the absorption efficiency about 20% and 15% compared to pure water in co-current and counter-current flows, respectively. It was also observed that a mixture containing 20 wt% of ionic liquid and 10 wt% of methyldiethanolamine can improve the absorption capacity about 10% compared to a 10 wt% MDEA aqueous solution without ionic liquid.

In this study, the thermodynamic modeling of SO2 solubilities in 14 Deep Eutectic Solvents (DESs) of different nature was investigated for the first time in literature. This is a challenging mixture to model. The thermodynamic modeling approach of γ − ϕ for vapor-liquid equilibria was used. The Cubic Plus Association Equation of State (CPA EoS) was used to represent the vapor phase and the NRTL and UNIQUAC models were both investigated for the liquid phase. The DESs were considered as pseudo-components and their physical properties calculated. Both the CPA-UNIQUAC and CPA-NRTL models showed good agreement with experimental values, with total AARD% of 2.9% and 3.1%, respectively. CPA-UNIQUAC shows slightly better results, while CPA-NRTL is a simpler model. In addition to the γ − ϕ approach, the ϕ − ϕ approach was investigated for all of the systems. However, the results were not reliable, even when incorporating binary interaction parameters as adjustable parameters in the model.

Deep Eutectic Solvents (DESs), as recently introduced green solvents, are interesting for different fields and applications. Most of the known DESs have high viscosities, which change dramatically with temperature. Therefore, the viscosity of a DES is most often one of the vital physical properties which must be known accurately. Because of the strong non-ideal interactions between the constituents, as well as the dramatic changes of DES viscosity with temperature, modeling and predicting the viscosities of DESs over wide ranges of temperatures is very challenging. In this study, a viscosity approach is used and implemented into two advanced association equations of state for different families of deep eutectic solvents. The cubic plus association (CPA) and the perturbed chain-statistical associating fluid theory (PC-SAFT) equations of state (EoSs), which are two powerful models to handle associating compounds, have been coupled with the friction theory, which is itself among the successful theoretical viscosity models of literature. Twenty-seven different types of DESs, for which density and viscosity data are available in open literature, were considered. A large density databank, consisting of 590 density data over wide ranges of temperatures and pressures, together with a large viscosity databank covering 253 viscosity data over wide ranges of temperatures at atmospheric pressure were collected. The resulting friction theory models with the CPA and PC-SAFT EoSs were checked against experimental data and their deviations were found to be the same and equal to 4.4%. Such accuracy showed the promising capability of both models. By changing the hydrogen bond donor types for a fixed hydrogen bond acceptor, the accuracies of the models were also shown to be good with respect to experimental values. In addition, both models perfectly followed the trends of changing ratios of hydrogen bond donors to hydrogen bond acceptors. The viscosity-temperature trend of the different DESs was also successfully modeled.

With the aim of investigating the solutions of ethane shortage in a commercial ethylene plant, addition of propane as supplementary feedstock and increasing steam to hydrocarbon ratio were proposed as possible strategies. These strategies were proposed to compensate for the ethane shortage in the thermal cracking unit of the commercial plant. Run length, ethylene yield, and propylene yield were considered as the determining factors to appraise the strategies. The major contribution of present work would be the investigation of effect of feed shift on the run length of the steam cracker. Regarding this, five different cases were investigated in real plant condition. To include all the aspects of process, a mathematical model with reasonable assumptions was developed and then validated against the real plant data. Based on the obtained results, increasing propane concentration leads to increase in propylene yield and decrease in ethylene yield. Besides, run length of process was obtained to be longer in the cases with higher propane content in the feed stream.

The thermodynamic modeling of a new generation of solvents, deep eutectic solvents (DESs) is investigated. Because hydrogen bonding is a dominant molecular interaction, the cubic plus association (CPA) equation of state (EoS) was chosen for modeling. This is the first study to model DES density and carbon dioxide solubility using CPA. Fifteen different DESs were chosen which have density data, as well as CO2 solubility data, available in the literature over wide temperature and pressure ranges. To date, this is the most extended and global databank of DESs which has been employed in relation to a complex EoS. The density data were used to optimize the CPA parameters. The CPA EoS proved to be capable of accurately modeling pure DES densities. The validity of the optimized CPA parameters was further validated with literature density data of mixtures of DES + water, which were estimated successfully by a purely predictive procedure. To calculate CO2 solubility in DES, all the possible association schemes of ...

The use of industrial waste streams as a source of biomass is beneficial, not only to reduce environmental problems, but also to save valuable resources. Waste streams containing volatile fatty acids (VFAs) are one such example. However, separation from these streams is challenging because of the low concentrations of VFAs found in aqueous solutions. In this study, medium-chain fatty acids (MCFAs) diluted in an organic solvent are used as extractants for VFAs from dilute aqueous solutions. MFCAs have the advantage of forming double hydrogen bonds, which makes them very interesting for the recovery of VFAs. Liquid-liquid extractions (LLE) are carried out using hexanoic, octanoic or decanoic acid as the MFCA extracting agents, diluted with either hexane or toluene for economy. The various VFAs extracted consist of either acetic, propionic or butyric acid. In this manner, the effect of parameters such as the alkyl chain length of the VFAs and MCFAs and the nature of diluent have been investigated. In addition, the influence of the concentration of MCFAs in the diluent (n-hexane and toluene) on the extraction efficiency of the various VFAs has been determined. Results suggest that the decrease in extraction efficiency by diluting an MCFA with a conventional solvent is not at all a linear function of volume fraction. Therefore, a diluted MFCA has the potential to be the more economic extractant rather than a pure MCFA, as very little extraction efficiency is sacrificed over relatively large ranges of dilution.

In this study, a new simple, general, accurate and easy-to-use correlation has been developed for estimating the thermal conductivities of pure ionic liquids (ILs) over a wide range of temperatures at atmospheric pressure. In addition to the abilities mentioned, a further goal of this work was to develop a thermal conductivity correlation which does not require, as input parameters, any other physical properties, once a single thermal conductivity data point is available. This can be a valuable advantage, especially in the field of ILs for which many physical properties are unavailable. The new correlation has been proposed based on 378 thermal conductivity temperature data points from 44 different IL types. The proposed correlation, in comparison to two well-known and commonly used group contribution models and one literature correlation, shows much higher accuracy with respect to experimental values. Calculations covering all of the investigated ILs in this work resulted in AARD% values of 1.0%, for the proposed model. It is also more widely applicable, as indeed, it can estimate IL thermal conductivities with a very simple formula and without the need for other physical properties, even molecular weight and molecular structure.

Accurate knowledge of the surface tension of liquid mixtures is of considerable importance in the development of chemical processes that involve mass and heat transfer across phase interfaces. Despite the significant progress made in the development of advanced equations of state (EOS) for accurate representation of thermophysical properties, as well as sophisticated models for the thermodynamic equilibrium of highly non-ideal mixtures, they nonetheless have been to a large extent underrepresented in the prediction and correlation of the surface tension of such systems. In the current work, a modified version of the Butler equation is adopted alongside the Cubic Plus Association (CPA) EOS, with the objective of predicting and correlating the surface tension of binary liquid mixtures of associating compounds. In doing so, the experimental data of aqueous and non-aqueous mixtures of alcohols, glycols, acids, and phenol, comprised of 238 data points belonging to 18 binary mixtures are studied. It is shown that by incorporation of an association term based on the Wertheim's first-order thermodynamic perturbation theory, the CPA EOS can satisfactorily predict the values of surface tension with an AARD of only 9.78%, compared with deviations of 73.87% and 28.38% obtained for the Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR) EOSs, respectively. Also, a major advantage of the proposed model is its inherent capability to simultaneously estimate the composition of the surface phase alongside the mixture surface tension. In addition, with only one adjusted binary parameter, AARDs of 5.29%, 7.09%, and 11.02% are obtained for the correlation of the experimental data using the CPA, SRK, and PR EOSs, respectively.

Deep eutectic solvents (DESs) are emerging green solvents with very unique characteristics. Their contribution to atmospheric pollution is negligible, and they can be &ldquo, designed&rdquo, for desired properties. In this study, the feasibility of applying DESs (Reline, Ethaline, or Glyceline) as absorbents in absorption refrigeration cycles was investigated. The sophisticated cubic-plus-association (CPA) equation of state, considering the strong intermolecular interactions of such complex systems, was used to estimate the thermodynamic properties. At a fixed set of base case operating conditions, the coefficients of performance were calculated to be 0.705, 0.713, and 0.716 for Reline/water, Ethaline/water, and Glyceline/water systems, respectively, while the corresponding mass flow rate ratios were 33.73, 11.53, and 16.06, respectively. Furthermore, the optimum operating conditions of each system were estimated. To verify the feasibility, results were compared to literature systems, including LiBr/water and various ionic liquid/water systems. The results indicate that DES/water working fluids have the potential to be used in such cycles. Since DESs have the characteristic to be tuned (designed) to desired properties, including their solvent power and their enthalpies of absorption, much further research needs to be done to propose new DESs with higher energy efficiencies.

Nowadays, Deep Eutectic Solvents (DESs) are considered as green solvents in many research fields. Knowledge of the physical properties of DESs can pave the way to their useful utilization. One of the important properties of a DES is its heat capacity. Besides experimental measurements, which are expensive and time consuming, it is vital to have models for the estimation of heat capacities. A generalized model is presented to estimate the heat capacities of DESs. In this regards, 505 isobaric heat capacity data points, over the wide temperature range of 278.15 to 363.15 K, from 28 DESs of different natures were used to develop the model. Up to date, this is the largest data bank investigated for isobaric heat capacities of DESs in the open literature. Based on this database, a simple, straightforward, yet precise correlation was developed to estimate the heat capacities of DESs as a function of temperature, molecular weight, critical pressure, and acentric factor. The absolute average relative deviation (AARD%) of the proposed correlation for all of the investigated data points is 4.7%, which shows that the calculated results are quite promising for such complicated systems. To the best of our knowledge, up to now, there are no generalized models for estimating the heat capacities of deep eutectic solvents, and this is the first model in the literature, therefore, it can be of great value to researchers in the field. The model has even further significance when considering that it is actually needless of any experimental data as input. This is because the physical properties used in the correlation to identify the substance are themselves obtained by group contribution methods. In practice, the only required information to use this simple and predictive model is the chemical structure.

In this study, the densities of the pseudo-binary systems of water and the deep eutectic solvent, 1 choline chloride + 4 phenol were measured and reported for the first time in literature, and a comprehensive investigation on the various volumetric properties was carried out. Nine mixtures, with different compositions of water, were prepared. The densities of the prepared mixtures, as well as pure water and pure deep eutectic solvent (DES) were measured within a temperature range of 293.15–333.15 K at atmospheric pressure. Various volumetric properties, such as excess molar volumes and isobaric volume expansions, partial molar volumes and excess partial molar volumes were calculated for the investigated compositions. Furthermore, partial molar volumes and excess partial molar volumes at infinite dilution were estimated for water and the DES. By analysing the calculated properties, the interstitial accommodation effect was suggested for the investigated mixtures. The stronger tendency of water to be solvated in the mixture, as compared to the DES, was observed for all investigated temperatures. This suggests that, most probably, hydrogen bonds in the investigated mixtures are established in a manner in which water molecules are located at central positions, surrounded by the DES pseudo-molecules.

A group contribution procedure, on the basis of SAFT-γ equation, is extended to cover new families of imidazolium-based ionic liquids (ILs), with either the [MeSO3], [MeSO4], [EtSO4] or [CF3SO3] anions. The IL groups of the SAFT-γ equation were fit to IL density data at temperatures from 293.15 to 393.15 K. Pressures varied up to 60 MPa. The groups corresponding to the CO2+IL systems were optimized by the solubility data of CO2 in the ILs. The binary system data covered temperatures from 273.15 to 413.15 K, with pressures going up 27 MPa. In addition to the accuracy of estimations, the strength of SAFT-γ in predictions was investigated by estimating both the density of ILs, and the bubble-point pressures for some mixtures of CO2+ILs which were not considered in the fitting process. The average absolute relative deviations in density and bubble pressure predictions did not exceed 2.78% and 4.97%, respectively.

In this study, focused radio wave (RW) assisted leaching was investigated for the first time to considerably enhance the efficiency of copper leaching from its low-grade ores. For this purpose, the effect of exposure to radio wave electromagnetic irradiation was experimentally investigated. Two series of leaching tests were conducted, in the form of agitated slurry and fixed-bed column modes. The experimental results indicated a significant improvement of recovery in both modes. The most probable mechanisms for enhanced recoveries could be the dielectric heating through concentrated irradiation. For less than 24 h of leaching in the fixed-bed column under irradiation, the recovery improved by about 40% (~60% for leaching vs. ~100% for RF leaching), as compared to the same tests with no irradiation, while the agitated leaching tests showed an increase of up to 10% under irradiation. It is concluded that electromagnetic technology, even in the range of radiofrequency (

CO2 solubilities in the deep eutectic solvent (1 choline chloride +3 triethylene glycol) were measured at the four temperatures of 303.15, 313.15, 323.15 and 333.15 K and pressures up to 30 bars. Measurements were carried out in a newly designed, built and validated high pressure solubility apparatus. The measured data were modeled by the cubic plus association (CPA) and the Soave-Redlich-Kwong (SRK) equations of state, with AARD% values of 5.52% and 7.30% for the CPA and SRK EoSs, respectively, showing the good correlative ability of both models. Furthermore, by calculating the standard Gibbs free energies of dissolution, standard enthalpies of dissolution and standard entropies of dissolution at infinite dilution, we found that the dissolution process is nonspontaneous and exothermic, with the CO2 - DES interactions being the stronger interactions. The solution becomes less chaotic and reaches a higher degree of order in the liquid phase after dissolution of CO2.

In this work, a three layer feed-forward artificial neural network, with 24 neurons, was constructed to estimate the viscosities of a wide range of ionic liquid families, including those based on the imidazolium, ammonium, pyridinium, pyrrolidinium, phosphonium, and isoquinolinium cations, together with various anions, as well as varying lengths of alkyl side-chain lengths. The model is a function of the molecular weight and structure of the ionic liquid, and the system conditions of temperature and pressure. It covers a temperature range of (273.15 to 393.15) K and a pressure range of (0.1 to 150) MPa. Results indicated the estimated values of viscosities of pure ionic liquids to be in good agreement with the experimental data. The training (correlating) and validation coefficients (R) were 1.00000 and 0.99955, respectively, while the training and validation performances (MSE) on the training and validation datasets were 4.36 × 10 − 8 , and 1.63 × 10 − 6 , respectively. The average absolute error value on the test dataset was 1.310%.

In recent years, absorption of carbon dioxide using nanofluids has increasingly gained attentions due to its unique advantages. In this study, the absorption of carbon dioxide using Sulfinol-M based nanofluids were investigated. Functionalized MWCNTs and Fe3O4 nanoparticles were dispersed in the absorbent in order to study their effects on absorption rate and equilibrium amount of absorption using a high pressure vessel equipped with a magnetic stirrer. The effects of different parameters including nanoparticle type, nanoparticle concentration in Sulfinol-M and initial pressure of CO2 in gas phase were investigated. The obtained results revealed that the presence of both nanoparticles in the based solvent can enhance the rate of absorption and also the equilibrium solubility to a maximum amount of 46.7% and 23.2%, respectively. MWCNT shows better effects and it increases the solubility up to 7.3% more than Fe3O4 nanoparticle under the same condition. In addition, the possible mechanisms regarding mass transfer augmentation and equilibrium solubility enhancement are discussed.

A simple and general atomic group contribution method is developed for the prediction of liquid densities of ionic liquids as a function of temperature and pressure. Available literature data are used as a comprehensive database, consisting of 25 850 data points for a vast variety of ionic liquid families, and within wide ranges of pressures (0.10–300 MPa) and temperatures (217.58–473.15 K). In developing the group contribution model, the idea was to propose a simple equational form, with straightforward groups which will be easy to use, yet be general and predictive for a vast range of ionic liquids at the same time. To do this, as functional groups, we have chosen atoms and a few small and simple groups. This feature makes the model rather capable and global for a wide range of ionic liquids. Despite the generality and simplicity of the model, and by considering that the only necessary information required to use this method is the chemical structure of the ionic liquid, a good accuracy (AARD% of 0.95%)...

Due to importance of acetylene removal from ethylene rich stream in polymerization units in order to prevent formation of highly explosive compounds, presenting any strategies improving the process efficiency has attracted researchers and industries interests. Proposing novel configurations in the reaction-regeneration cycles with lower energy consumption and enhanced catalyst lifetime leading to profits for the polymerization units is of a great interest. In this regard, a new configuration for the tail-end acetylene hydrogenation reactor of a commercial olefin plant was proposed in the present study. Based on the proposed configuration, a new protocol is applied to the process for utilizing total capacity of active catalysts in each fixed bed. A mathematical model based on component and energy balance was developed and validated to evaluate the operability of the proposed configuration. Operation of different runs in the new protocol was compared with the conventional configuration. The obtained results revealed that the new configuration is managed to decrease the volume of the regenerated catalyst in a 4-year period of operation. A 33.3% decrease in the volume of the regenerated catalyst was observed. Such an achievement was obtained without reducing acetylene conversion and ethylene yield.

In continuation of our earlier publication on the phase behavior of binary and ternary mixtures involving acetaldehyde, Versatic 10, and Veova 10, in this work we present bubble-point pressures of the binary and ternary systems of acetaldehyde, Versatic 9, and Veova 9. The measurements were carried out in the Cailletet equipment, which operates according to the synthetic method. The solubility data are presented within a temperature range of 298-353 K for the two binaries of acetaldehyde + Versatic 9 and acetaldehyde + Veova 9. The pressures required for complete solubility into one homogeneous phase ranged from 0.083 to 0.414 MPa in the temperature and concentration range considered. While both Versatic and Veova contain a C=O group, Versatic also contains an alcoholic OH, which makes its solubility in acetaldehyde more difficult. The solubility curve of Versatic 9 not only shifts to higher pressures compared to that of Veova 9, but also has an increased curvature, indicating its greater deviations from ideality. As the alkyl chain is increased by one carbon number to Veova 10 and Versatic 10, the absence and presence of the OH group in Veova and Versatic also result in greater and smaller curvatures of the solubility curves, respectively. The Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) equations of state were used to model phase equilibria of the binary systems of acetaldehyde + Versatic 9 and acetaldehyde + Veova 9. Results showed that both models have good agreement with the experimental values in this study. Two ternary mixtures of acetaldehyde + Versatic 9 + Veova 9 were also investigated experimentally for their bubble point pressures. While both components have one C=O group, Versatic 9 also contains an alcoholic OH, which Veova 9 lacks. Therefore, nonideal interactions are increased between the molecules of acetaldehyde and Versatic 9 due to the presence of this hydrogen-bonding group, as compared to the system of acetaldehyde + Veova 9.

The modification of alumina support of copper-based oxygen carrier using zirconium oxide is investigated in this study. The CO 2 modified chemical looping reforming (CO 2 -CLR) process is applied to evaluate the synthesized oxygen carriers at different reduction temperatures (550–750 °C). The presence of ZrO 2 in the support structure of oxygen carrier inhibited the deposition of coke on the samples. The results revealed that the addition of 20% zirconium oxide could effectively improve the efficiency of oxygen carrier at different reduction temperatures. In addition, the effect of CH 4 /CO 2 ratio in feed (0.5–3) and copper loading percentage (10, 15, 20, 25, 30) are investigated on methane and carbon dioxide conversion, hydrogen production yield and CO/CO 2 ratio. The synthesized oxygen carriers were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), BET and energy dispersive X-ray spectroscopy (EDX) techniques. The 15Cu/20Zr-Al as optimized oxygen carrier exposed a mesoporous structure with a high surface area of 315.9 m 2 g −1 . The redox results revealed that 15 Cu/20 Zr-Al oxygen carrier exhibited the highest activity and showed about 99.2% CH 4 conversion at a low temperature of 650 °C. This oxygen carrier revealed high stability for CH 4 and CO 2 conversion, hydrogen production yield and CO/CO 2 ratio during 16 redox cycles at 650 °C.

In the present study, the volumetric behaviour of mixtures of (ethaline + ethanol) was investigated for the first time. Ethaline, which is the mixture of choline chloride and ethylene glycol at a molar ratio of 1:2, is among the most well-known Deep Eutectic Solvents (DESs). Because of its rather low viscosities as compared to many DESs, it has gained the interest of researchers for use in different applications. In this work, isobaric densities of the mixtures of Ethaline + ethanol were measured and presented over the entire mixture concentration range within the temperature range of (293.15 – 333.15) K. Using the measured data, excess molar volumes of the mixtures were calculated and analysed. The negative values of excess molar volumes suggested the stronger interactions of hydrogen bonds in the mixture with respect to the pure states of its constituents. Additionally, partial molar volumes and excess partial molar volumes, as well as the corresponding values at infinite dilution, were calculated and analysed. It was found that both Ethaline and ethanol have the tendency to be solvated by the mutual unlike-molecule in the mixture, and this tendency is stronger for Ethaline. It is also suggested that within the established hydrogen bond networks in the mixture, the Ethaline pseudo-molecules are probably located at central positions, being mostly surrounded by ethanol molecules.

Deep eutectic solvents have aroused a great level of interest in recent years. In this regard, a simple model is presented for the calculation of viscosities of a wide range of deep eutectic solvents. Based on a databank covering 156 deep eutectic solvents of different natures, a straightforward, simple, accurate, and global correlation is proposed. This model, which covers wide ranges of temperatures, requires the critical pressure, critical temperature, and one reference viscosity data as its input parameters. Since the model has one set of global constants, it can be used for any DES. Apart from this correlation, a second approach was also taken in this study, which was to obtain the constants of the Vogel-Fulcher-Tamman (VFT) model for all of the investigated DESs. With this approach, the constants are individually fit to each DES, therefore, no physical properties are required as input. The average absolute relative deviation errors of 10.4% and 1.7% for the proposed model and the VFT model, respectively, are compared to literature models. The results indicate that the proposed correlation, in addition to its acceptable accuracy and simplicity, is a general model for the estimation of the viscosities of different-natured deep eutectic solvents.

In this study, a comprehensive investigation on the volumetric properties of mixtures of a deep eutectic solvent (DES) and an alcohol was carried out. Ethaline (1 choline chloride + 2 ethylene glycol), which is one of the more common DESs, and methanol were chosen to make the desired mixtures. Nine different mixture compositions of Ethaline + methanol, over the full range of concentrations, were prepared. Densities of pure Ethaline and methanol, and also nine mixture samples, were measured at five temperatures from 283.15 to 323.15 K and atmospheric pressure. The excess volumes of the investigated mixtures were calculated and modeled with the Redlich-Kister model. All of the calculated values of excess volumes were negative, which probably shows stronger hydrogen bond contributions and better interstitial accommodations in the mixtures with respect to the pure states. Furthermore, other volumetric properties, such as partial molar volumes and excess partial molar volumes at each composition and at infinite dilution were calculated. By analyzing the calculated volumetric properties, the greater tendency of Ethaline for solvation in the mixture was observed as compared to methanol. Therefore, it is suggested that probably the hydrogen bond networks in the mixture are created in a pattern in which mostly Ethaline occupies central positions, being surrounded largely by methanol molecules.

Nitrogen and oxygen are the main components of air. Liquid nitrogen is an alternative to fossil fuels. However, little attention has been paid to this energy resource. Liquid oxygen is not a fuel in itself, however, it can be used as an oxidizer to run vehicles. In this respect, gas hydrate technology can be of interest, as applicable media for nitrogen/oxygen transport or nitrogen/oxygen separation. Both nitrogen and oxygen have the tendency to form hydrates, especially at high pressures, with double occupancy of the large cavities of structure sII. Thermodynamic hydrate promoters (THPs) can be used to facilitate the formation of nitrogen or oxygen hydrates at more moderate equilibrium conditions. For this purpose, CCl4 can be a potential candidate. In this contribution, hydrate equilibrium conditions for binary mixtures of nitrogen + CCl4 (50 data points) and oxygen + CCl4 (41 data points) were experimentally measured. This was done using three different experimental equipment, namely: a tensimeter, the Cailletet apparatus, and a high-pressure autoclave. A thermodynamic model, according to the van der Waals-Platteeuw (vdW-P) solid solution theory, was then employed to predict the hydrate equilibrium temperatures of the aforementioned mixtures. The fugacities of the components in the mixtures were calculated through the Peng-Robinson (PR) EoS and the classical van der Waals mixing rules. The Kihara potential model was applied to represent the guest-host interactions. The results reveal that the model has the ability to predict the hydrate equilibrium temperatures with the average absolute deviation (AAD) of 0.32 K. The fractional occupancy calculations indicate that the CCl4 molecules mostly occupy the large cages and do not enter the small cages of sII hydrates because of their size, while nitrogen and oxygen have small contributions in the filling of the large cages of sII.

Among the fossil fuels, diesel has the major share in petroleum product consumption. Diesel demand in Iran has increasingly grown due to the low price of diesel, a high subsidy, and an unsuitable consumption pattern. During 2006–2007, this growth imposed 2.2 billion liters of imports, which were equivalent to 7.5% of diesel production in 2007 and cost about $1.2 billion. Therefore, the government implemented fuel rationing in 2007 and a targeted subsidy law in 2010. These projects have not gained effective control of consumption due to the wide gap between the international diesel price and the domestic price. Diesel import after the implementation of fuel rationing and the targeted subsidy law in 2011 imposed 3.6 billion liters of import and cost about $2.2 billion. Therefore, the government will need fundamental strategies and policies to face and control the negative impact on the economy and the environment. Third generation fuels, biofuels, as another supplementary approach seems to have the capability to reduce the petroleum requirement. This paper investigates the potential of biodiesel as diesel alternative fuel from oil seeds and microalgae in Iran along with evaluating the policy for reducing diesel consumption. Dunaliella salina as an indigenous green microalga isolated from the Maharlu Salt Lake was cultivated in an integration of an airlift system and a raceway pond (IARWP) to prove microalgal potentials in Iran. Additionally, the natural culture medium from the Maharlu Salt Lake was utilized for Dunaliella salina in order to commercialize and reduce cultivation cost. Compared to oilseeds, microalgae because of their high lipid content have much potential to solve a fuel consumption problem. This paper found that only 21 percent of cultivable land is needed to replace the diesel currently consumed in Iran with microalgal biodiesel.

The group contribution equation of state (GC-EoS) is extended to model gas solubilities in the homologous 1-alkyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl) imide family. The gases considered in this work are CO2, CO, H2, CH4, and C2H6. The model parameters were estimated on the basis of 1400 experimental data points in the temperature range of 278-460 K and pressures up to 160 bars. A correlation is also presented to calculate the critical diameter, a characteristic parameter of the GC-EoS repulsive term, as a function of the ionic liquid molar volume. Density data is most often available for ionic liquids; hence, the correlation provides a predictive method for ionic liquids not included in the parameterization process. The new parameters were then used to predict the phase behavior of binary mixtures containing different solutes (including C3H8, C4H10, and C6H14) and ionic liquids with different chain lengths than those used in the parameterization process. Fil: Pereda, Selva. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina Fil: Raeissi, Sona. Shiraz University; Irán Fil: Andreatta, Alfonsina Ester. Universidad Nacional de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Planta Piloto de Ingeniería Química (I). Grupo Vinculado al Plapiqui - Investigación y Desarrollo en Tecnología Química; Argentina Fil: Bottini, Susana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina Fil: Kroon, Maaike. Eindhoven University of Technologie; Alemania. Technische Universiteit Eindhoven; Alemania Fil: Peters, Cor J.. Technische Universiteit Eindhoven; Alemania. Eindhoven University of Technology; Alemania. The Petroleum Institute. Chemical Engineering Department - Abu Dhabi; Emiratos Arabes Unidos

The aim of present study is to develop a mathematical model to predict water and salt separation efficiencies in an industrial two stages crude oil desalting process. The considered process consists of mixing valve and electrostatic drums connected in series. The desalting plant is modeled based on the population balance method considering water droplet breakage and coalescence terms to predict droplet size distribution. The class method as a common mathematical technique is selected to solve population balance equation. The accuracy of the developed mathematical model and considered assumption is evaluated using taken data from an industrial desalting plant. Then, the effect of mixing valve pressure drop, flow rate of fresh water and strength of electric field is studied on the desalting and dehydration efficiencies. The simulation result shows that increasing flow rate of fresh water from 3% to 6% decreases salt content in the treated crude oil from 2.06 to 0.71 PTB.

The goal of this study was to propose, a general, yet simple and accurate model for the estimation of the standard molar chemical exergies of various organic compounds, often used in the industries. With this goal in mind, for the first time in literature, the atomic contribution approach was considered, and the feasibility of adopting such a simple method to calculate chemical exergies was investigated. A large data bank, consisting of 4129 organic compounds from wide ranges of families, was gathered from the literature, and divided into training and test datasets. Upon investigating various functionalities, and optimizing using the training databank, two atomic contribution models were proposed to calculate the standard enthalpy and entropy of formation, from which, the standard molar chemical exergy of a compound is calculated. The AARD% value for estimating the standard molar chemical exergy of the entire database, consisting of both the training and testing datasets, was 0.64%, which shows not only the feasibility of applying the atomic contribution approach for the calculation of this property, but also high accuracy as compared to more tedious literature models. Since the proposed models require knowledge of only the chemical formula and the normal boiling point of the desired compound, it is indeed in line with our purpose of simplicity and generality, and can easily be incorporated into computer codes. Considering that it is also global and quite accurate, this model even has great potential to be used in energy and chemical-related software.

Amino acid salts (AAS) are mentioned as potential solvents for the separation and capture of carbon dioxide (CO2). This study investigates the aqueous solution of Potassium Glutaminate (K-Glu) solvent from different viewpoints including equilibrium solubility of carbon dioxide varying the concentration and absorption temperature at different pressures, reaction kinetics and mechanism between K-Glu and CO2, heat of absorption and cyclic absorption and regeneration efficiency. The reaction rate was calculated using the obtained experimental data and quasi first order overall reaction rate is proposed. The successive absorption-desorption preliminary tests showed a negligible drop in CO2 capture capacity over consecutive cycles through regeneration at 343.15 K. The proposed solvent has the advantages of high absorption rate and capacity (compared with monoethanolamine and N-methyldiethanolamine) with interesting aspects such as lower corrosion rate, environmental biening and high resistance against thermal and oxidative degradation covering the shortcomings of conventional amines, which considers it as a potential new solvent.

Ionic Liquids (ILs) are designer solvents with very unique properties, resulting in the exponential growth of publications in the field. Speed of sound can be considered as one of the important thermodynamic properties of compounds, since many other thermophysical properties can be determined using the speed of sound, including density, isentropic compressibility, isothermal compressibility, thermal conductivity, heat capacity, Joule-Thomson coefficient, and bulk modulus. Since ILs are designer solvents, much of their properties are unknown, hence, knowledge of their speeds of sound can be quite valuable. Two new straightforward models, with totally different approaches and input parameters, are proposed to estimate the speed of sound in ILs: an atomic contribution model, which only considers the atoms as building blocks to create the molecule and estimate its speed of sound; and a novel correlation. The atomic contribution model is the first which requires knowledge of only the chemical formula of the IL, making it needless of, not only any physical properties, but also the molecular structure which group contribution methods do require. This is considerable progress, as it will cover the majority of future ILs, which have not even been synthesized, and it does not have the ambiguities and difficulties of conventional group contribution (GC) methods for such complex structures. The further notable progress is its easy incorporation into computer programs, which is a serious setback with GC models. However, while being very straightforward and easy-to-use, it is more global than literature models. In addition to the atomic contribution method, a novel empirical correlation is proposed, with a new perspective. Both proposed models are quite reliable, while being very simple, and general.

Nowadays, environmental issues and the energy crisis are among the most important challenges to researchers. The necessity of increasing the energy efficiency of industrial processes is vital. If this efficiency increase is additionally done by using sustainable components, environmental issues are also alleviated. Deep eutectic solvents (DESs) are a new generation of green solvents with unique properties. This has led to the exponential growth of research in the field, oriented towards green chemistry and green processing. This study investigates the feasibility of utilizing DESs in the petroleum industries by considering the case study of capturing CO2 from natural gas, resulting in a purified gas with greater heating value. The idea is to utilize the DES as an absorbent, in place of the conventional Selexol. The pressure swing absorption process was simulated for two different DES, namely Reline and Glyceline. The purity of the methane stream was 89.1% when using Selexol, and 90.1% and 79.6% for Reline and Glyceline, respectively. The carbon dioxide stream showed even greater purity differences when DESs were used (98.3%, 98.4% and 94.9% CO2 when using Reline, Glyceline, and Selexol, respectively). Furthermore, energy and exergy analyses were carried out on the proposed plants. While the overall duties were less for the plants using DESs (−51.27, −11.13, and 15.17 and kW for Reline, Glyceline, and Selexol, respectively), the exergy destructions were not (146.78, 165.64, 96.54 kW for Reline, Glyceline, and Selexol, respectively). The results indicated the feasibility of using DESs as potential physical solvents in such industries.

Deep eutectic solvents (DESs) mostly comply with the principles of green chemistry. Therefore, they are being widely investigated due to their great potential for a variety of applications in the industries. However, it is necessary to have accurate (thermo)-physical property information on any solvent before it can pave its way into the industries. Among such properties, density as a function of temperature is one of the most important. In this study, a simple, accurate and global correlation is proposed to estimate the densities of a large number of DESs of different natures. The proposed model is a function of the critical temperature, critical volume and acentric factor of the DES, as well as the temperature of the system. In this way, the model is capable of accurately predicting the densities of DESs without the need for any reference temperature density data, in contrast to most of the literature models that do require a reference data point. The average relative error for 149 DESs of different natures was estimated to be 3.12% by the proposed model, indicating its accuracy compared to previous models.

Dielectric barrier discharge (DBD) plasma reactor is an innovative advanced oxidation technology for degradation of organic dye in water. In this study, the crystal violet (CV) solution was exposed to a post-discharge DBD plasma in which O2 was used as the feed gas. In this mode, the liquid target is isolated from the plasma medium and the plasma effluent gas is bubbled across the liquid target to increase mass transfer between reactive species and the solution. The influence of operating parameters including applied power and gas flow rate was studied. It was shown that increasing reactor temperature resulted in the reduction of CV removal. Dilution of the plasma forming gas (pure O2) with Ar enhanced the CV removal up to 44%. The kinetic model of CV bleaching was shown to follow a first-order reaction. In the most suitable experimental condition after one minute treatment, the CV decolorization of 100% was achieved, and the total organic carbon (TOC) dropped to zero. Preliminary investigation into the byproducts through UV-VIS, TOC and GC-MS were done which showed the disappearance of the aromatic rings. This work also outlines current operation methods for plasma treatment of organic dyes in water and compares their performance in terms of energy efficiency, degradation rate constant and formation of main reactive species. The interesting results of post discharge treatment which can be compared quite favorably with those achieved by other operation methods, are the degradation rate constant of 4.37 (1/min) and energy efficiency of 12.2 (g/kWh).

Reports on deep eutectic solvents (DESs), as a new category of green media following ionic liquids (ILs), are increasingly emerging in the literature. Because of the dramatically large number of DE...