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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.

In this work, the equilibrium conditions of xenon hydrates have been measured within wide pressure and temperature ranges. Various experimental equipment have been used for this purpose, namely the tensimeter, the Cailletet apparatus, and the high-pressure autoclave. A number of three-phase equilibrium data points were measured for liquid water-hydrate-vapor (Lw-H-V) and the ice-hydrate-vapor (I-H-V). It was concluded that there is a good consistency between the experimental data points measured in this work and those obtained by the other groups in the literature. A modified van der Waals-Platteeuw (vdW-P) model was used to predict the xenon hydrate stability conditions. The Kihara spherical-core potential function was used to represent the intermolecular forces between the water molecules and the xenon molecules in the cavities. The fugacity of xenon in the vapor/gas phase was computed using the Peng-Robinson (PR) EoS. The solubility of xenon in the liquid phase was calculated through the Krichevsky-Kasarnovsky equation. The investigated model had the ability to predict the xenon hydrate stability conditions with good accuracy within wide ranges of pressures and temperatures, resulting in an average absolute deviation (AAD) of about 0.61 K for (Lw-H-V) and 0.42 K for (I-H-V) equilibrium temperatures.

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.

Because of the special nature of ionic liquids, consisting of large heterogeneous organic cations and either an organic or inorganic anion, they possess interesting physical properties, such as negligible vapor pressure, low melting temperature, and high viscosity. The high viscosities of ionic liquids can be useful in some industries and for certain applications, such as lubricants. In this study, the viscosities of eight different ionic liquids and their binary mixtures with water have been investigated. Two easy-to-use correlations have been proposed, one for the estimation of viscosities of pure ionic liquids, and the other for their aqueous mixtures. The simple correlations are applicable at various temperatures at atmospheric pressure, and in the case of the mixture correlation, at various molar compositions. For the pure component correlation, an absolute average relative deviation of 2.97% was obtained for a total of 245 pure ionic liquid (and pure water) data, while for the mixture correlation, an absolute average relative deviation of 6.72% was obtained for a total of 512 viscosity data points for mixtures of ionic liquids with water. Such error values show the good agreement of both the proposed pure component and aqueous mixture correlations with respect to the corresponding experimental values. The proposed pure ionic liquid viscosity model was also compared to the two common literature correlations of Vogel and Daubert and Danner, after optimizing these two literature models to obtain the necessary equation coefficients for ionic liquids. Also, the newly-proposed mixture viscosity correlation was compared to the Grunberg and Nissan method for mixtures, coupled with three different pure viscosity models, to calculate the viscosities of mixtures of ionic liquids with water. Comparison of error values indicated the two correlations of this work to be more accurate than the above literature models for both pure and mixture viscosities.

The heat capacities of pure ionic liquids (ILs) are among the thermophysical properties that are required for certain engineering calculations and designs. In this study, a simple correlation is presented for the prediction of the heat capacities of pure ionic liquids. This correlation is a temperature-dependent relation that uses temperature, molecular weight and the number of atoms (such as carbon, hydrogen, oxygen, nitrogen, etc.) in the structure of the IL as input parameters. A dataset of approximately 128 different ILs, consisting of 4822 data points, was used to develop and validate this general correlation, covering a temperature range from 190 to 663 K. Nearly three-quarters of the data were used for optimization and a quarter for validation. The resulting correlation gives good estimations for heat capacities, while having a number of advantages over previous literatures methods. These advantages include (a) being very simple; (b) not requiring any experimental data as input parameters; (c) being more global than previous literature models by having been constructed over a larger databank of ionic liquids; (d) being accurate. The average absolute relative deviation (AARD%) was calculated to be 5.8% for the optimization dataset, and 5.6% for the validation dataset. This is smaller than what is obtained for the literature atomic-contribution methods proposed by Farahani et al. and Sattari et al., with AARD% values of 14.2% and 6.6%, respectively, based on the validation dataset of this study.

Mixtures of carbon dioxide and secondary butyl alcohol at high pressures are interesting for a range of industrial applications. Therefore, it is important to have trustworthy experimental data on the high-pressure phase behavior of this mixture over a wide range of temperatures. In addition, an accurate thermodynamic model is necessary for the optimal design and operation of processes. In this study, bubble points of binary mixtures of CO2 + secondary butyl alcohol were measured using a synthetic method. Measurements covered a CO2 molar concentration range of (0.10–0.57) % and temperatures from (293 to 370) K, with pressures reaching up to 11 MPa. The experimental data were modelled by the cubic plus association (CPA) equation of state (EoS), as well as the more simple Soave–Redlich–Kwong (SRK) EoS. Predictive and correlative modes were considered for both models. In the predictive mode, the CPA performs better than the SRK because it also considers associations.

Kinetics of the reactions of anisole, a model compound representative of lignin-derived bio-oils, with H2, catalyzed by Pt/Al2O3, were investigated with a fixed-bed tubular microflow reactor at 573–673 K, 8–14 bar, and space velocities in the range of 3–240 (g of anisole)/(g of catalyst × h). Selectivity–conversion data were used as a basis to propose an approximate reaction network and estimate parameters in approximate rate equations. The reactions include the following: anisole conversion to phenol by hydrogenolysis, to 2-methylphenol by transalkylation, to 2,4-dimethylphenol, 2,4,6-trimethylphenol, and 2,3,5,6-tetramethylphenol by transalkylation and alkylation, to benzene by hydrodeoxygenation (HDO), and to hexamethylbenzene by HDO and alkylation. The primary reactions are satisfactorily represented with the approximation that each is first-order in the organic reactant. The apparent activation energy for the hydrogenolysis reaction that leads to phenol formation is approximately 25.3 kJ/mol, and the...

In this study, an imidazolium-based ionic liquid (IL), 1,3-dimethylimidazolium dimethyl phosphate ([Mmim][DMP]), was applied for pretreating sugarcane bagasse to produce bioethanol. The main goal of this study was to investigate the feasibility of bagasse pretreatment with this IL, and to verify the effect of different operational parameters on the pretreatment process. Results indicated that temperature and duration of IL-pretreatment have optimum values. Within the range investigated, a maximum fermentable sugar conversion of 70.38% was achieved with this IL at 120 °C and 120 min. The corresponding value was 28.65% for the untreated biomass. The main cause for the observed enhancement in enzymatic hydrolysis was the reduction of cellulose crystallinity in the IL-pretreated biomass, as compared to the untreated sample, because it resulted in higher accessibility of the enzymes to the biomass after pretreatment. Moreover, the results indicated that aqueous [Mmim][DMP] mixtures are not as effective for pretreatment as the pure IL.

In this study, a volume-translated version of the Peng–Robinson equation of state (PR EoS) is developed for ionic liquid + polar solvent mixtures to estimate molar volumes within a range of compositions and temperatures. The ionic liquids investigated consisted of various combinations of either the 2-hydroxyethylammonium or the alkyl-methylimidazolium cation with various alkyl chain lengths, with the anions methyl-sulfate, ethyl-sulfate, hydrogen-sulfate, dicyanamide, acetate, bis(trifluoromethylsulfonyl)imide, and tetrafluoroborate. The polar solvents consisted of water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetone, nitromethane and dichloromethane. The volume shift parameter, c, was first optimized for all of the systems investigated at each composition and temperature. Based on the values obtained, it was observed that temperature-dependency is negligible. Therefore, a generalized equation was presented for the c parameter as a function of the molar composition of the polar solvent and the molecular weight of the ionic liquid. This relation, which contains a combination of exponential, logarithmic and polynomial terms, was able to improve the predictions of the PR EoS and reduce the errors with respect to experimental data. The average errors of the conventional PR EoS and the volume-translated PR EoS (both without using any binary interaction parameters) were equal to 14.92% and 5.91%, respectively. The added advantage of using this correlation is that it omits the need to optimize any binary interaction coefficients in such highly nonideal systems, making it a very simple and practical engineering tool for the industries, while at the same time increasing predictive accuracy.

This study investigated the catalytic upgrading of 4-methylanisole using Pt/γ-Al2O3 in the presence of hydrogen with a fixed-bed tubular flow reactor at 573–673 K, 8–20 bar, and space velocities in the range of 3–120 (g of 4-methylanisole)/(g of catalyst × h). Selectivity-conversion data were used to determine an approximate reaction network. It is observed that the scission of the Cmethyl–O bond is faster that the scission of the Caromatic–O bond. So 4-methylphenol forms as a primary intermediate product via scission of the Cmethyl–O bond, and then hydrogenolysis of the Caromatic–O occurs giving toluene. Also another possible deoxygenation route involves a direct Caromatic–O bond-breaking reaction, leading to toluene. Multiple transalkylation reactions including intramolecular and bimolecular rearrangement account for methylphenols with multiple methyl substituents. The major products were 4-methylphenol, 2,4-dimethylphenol, and 2,4,6-trimethylphenol. So we inferred that transalkylation involving methyl ...

Xylenes are aromatic hydrocarbons naturally present in petroleum and crude oil. Since market demand has shown a growing tendency toward xylenes consumption, investigators have been seeking for more efficient ways of their production by converting surplus toluene and less useful heavy aromatics to more valuable xylenes by means of disproportionation/transalkylation reactions. In this study, a novel radial-flow packed bed reactor configuration has been proposed for transalkylation reactions owing to its remarkably lower pressure drop in comparison to axial flow packed bed reactors. According to the complex nature of the feedstock, an accomplished reaction network based on 18 pseudo-components and 39 reactions was applied to design the reactor more reliably. Afterwards, the differential evolution (DE) method was used in order to optimize the operating conditions of the proposed reactor design. Finally, the performance of the optimized reactor was compared with that of an optimized conventional axial flow packed bed reactor to ascertain the superiority of the proposed reactor configuration.

In the present study, an accomplished reaction network is developed for commercial conversion of heavy reformates to more valuable xylenes. The proposed kinetic model is based on 18 pseudo-components and 39 related reactions in which 7 different types of reactions are included. Thermodynamic principles are also applied to predict the reversibility of the reactions. To estimate the reaction rate constants, the absolute deviation between the model results and observed data are minimized applying differential evolution (DE) optimization method. To prove the accuracy of the proposed model, simulation results are compared with the plant data and an acceptable agreement is achieved. Then, the effect of operating conditions on the reactor performance is verified. The results of this work show that increasing the inlet temperature and molar flow rate up to certain values would improve the xylenes production.

The paraffin group has a major role in the surface properties of hydrocarbon reservoirs. Because of its importance, this work reports new experimental density data for binary mixtures of heptane + hexadecane at temperatures and pressures ranging from 313.15 to 393.15 K, and 0.34 to 44.47 MPa, respectively. Five compositions were investigated, consisting of pure heptane, pure hexadecane, and their binary mixtures at heptane mole fractions of 0.4296, 0.6932, and 0.8748. An Anton Paar vibrating-tube densimeter was used to measure the densities. The resulting density data were fit to a Tait-type equation, showing deviations of less than 0.12% in AAD%. Excess volumes were calculated from the experimental data and fit to the Redlich–Kister equation. In addition, partial molar volumes of the components at infinite dilution and excess partial molar volumes of the components at infinite dilution were calculated. The isobaric expansion and the isothermal compressibility were also driven from the Tait-type equation.

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.

The conversion of cyclohexanone catalyzed by Pt/γ-Al2O3 in the presence of H2 was investigated with a fixed-bed tubular flow reactor at temperatures in the range of 573–673 K, a pressure of 14 bar, and space velocities in the range of 3–120 g of cyclohexanone/(g of catalyst × h). Data determined at low conversions of cyclohexanone identify the kinetically significant reaction classes (hydrogenation, dehydrogenation, hydrodeoxygenation, dehydration, and condensation) and quantitatively represent the initial product distribution. The pseudo-first-order rate constants for formation of the main products of cyclohexanone conversion under initial reaction conditions decrease in the following order: phenol > 2-cyclohexylidenecyclohexan-1-one > 2-methylphenol > cyclohexylbenzene > cyclohexane > biphenyl > 2-cyclohexen-1-one > 2-cyclohexylcyclohexan-1-one > 2-phenylphenol > cyclohexene > 2-cyclohexylphenol. The apparent activation energy for the dehydrogenation reaction that leads to phenol formation is approximat...

In this study, the behavior of derivative properties estimated by equations of state, including isochoric heat capacity, isobaric heat capacity, speed of sound, and the Joule-Thomson coefficient for pure compounds and a mixture, has been investigated. The Schmidt-Wagner and Jacobsen-Stewart equations of state were used for predictions of derivative properties of 10 different pure compounds from various nonpolar hydrocarbons, nonpolar cyclic hydrocarbons, polar compounds, and refrigerants. The estimations were compared to experimental data. To evaluate the behavior of mixtures, the extended corresponding states principle (ECS) was studied. Analytical relationships were derived for isochoric heat capacity, isobaric heat capacity, the Joule-Thomson coefficient, and the speed of sound. The ECS calculations were compared to the reference surface data of methane + ethane. The ECS principle was found to generate data of high quality.

In this study, a feed-forward artificial neural network, with three layers and seventeen neurons, was constructed to estimate the densities of a wide range of ionic liquid families including those based on the imidazolium, ammonium, pyridinium, pyrrolidinium, 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 condition of temperature and pressure, which covers a temperature range of (273.15 to 393.17) K and a pressure range of (0.1 to 100) MPa. Therefore, no additional experimental data on the ionic liquid is required as input parameter(s), which makes this technique quite versatile. It was observed that the estimated values of densities of pure ionic liquids have very good agreement with the experimental data. The training correlating coefficient ( R ), the training performance (MSE), and the average absolute error on the training dataset were 0.99997, 6.04 × 10 −6 , and 0.019%, respectively. The average absolute error value on the test dataset is 0.014%.

The already numerous industrial applications of alcohols is continuously growing to even higher significance. Accurate estimations of the physical properties of various alcohols within wide ranges of pressures and temperatures are necessary in the design and optimum operation of such processes. In this study, high-pressure liquid densities of the first six members of the normal alkanol family were predicted as a function of temperature and pressure. This was done using two different approaches: The computer method of support vector machine (SVM) and the thermodynamic model of Cubic Plus Association Equation of State (CPA EoS). A total of 2979 experimental data on alcohol density, also covering high pressure and high temperature conditions, were obtained from literature. The results of the calculations show that the value of AARD% for all of the 2979 data was 0.06% for the SVM computer model and 1.36% for the thermodynamic CPA model.

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).

A feed-forward neural network was constructed and tested to estimate the viscosities of binary mixtures of five different types of ionic liquids with various polar and non-polar solvents within a range of temperatures. The ionic liquids investigated had various anions and consisted of either the imidazolium, ammonium, pyridinium, pyrrolidinium, or isoquinolinium cations, with various cation alkyl side-chains. Together, a total of 1996 experimental data were collected from previously published literature and divided randomly into three different datasets: 1775 data points making up the training and validation datasets, and 221 data points selected as a test dataset. The molecular weight and group structure of the ionic liquid, the molecular weight and reduced boiling temperature of the solvent, and the molar composition, temperature, and pressure of the system were selected as the independent input variables. Results indicated that the network structure presented in this study is capable to estimate the viscosity of such nonideal binary mixtures, consisting of a range of ionic liquids and solvents, with an average relative error of 0.6%.

High pressure–temperature isopleths were obtained, experimentally, for the binary system of methanol + ethylene within a temperature and pressure range of 293–373 K and 38–119 bar, respectively. The experimental results were modeled using the Cubic-Plus-Association (CPA), Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK) equations of state. The ability of the CPA model to predict the phase behavior of methanol + ethylene is much better than the SRK and PR models. However, even though the p–T diagrams indicate that the CPA equation of state correlates well with the experimental results, by increasing ethylene concentrations, the errors of CPA increase due to the solvation that occurs in methanol + ethylene systems. In this work, the effect of solvation is also investigated. Results show that deviations from experimental data are less for CPA with solvation than for the CPA without solvation. Correlations are presented for the binary interaction (kij) and the association volume (βAiBj) parameters to model the phase behavior of methanol + ethylene, as both of these parameters were indicated to be temperature-dependent.

Microbial enhanced oil recovery (MEOR) process is divided into two main categories, namely in-situ and ex-situ techniques. It utilizes reservoir microorganisms or specially selected bacteria to use their metabolites for more oil recovery from depleted oil reservoirs. In the present study, the potential of two biosurfactant-producing strains of Enterobacter cloacae and Bacillus stearothermophilus SUCPM#14 were investigated on tertiary oil recovery efficiency in carbonated cores using different designed injection protocols. The required operational time, process cost and proper selection of bacterial formulation during the MEOR process were the main objectives of this study. The results of interfacial tension (IFT) measurements demonstrated the capability of E. cloacae to reduce the water/crude oil IFT from 30 to 2.7 mN/m after 24 h cultivation, while B. stearothermophilus SUCPM#14 was able to slightly reduce the IFT from 30 to 15 mN/m in the same period of time. The core flooding tests showed different bacterial formulations using various injection patterns, leading to different oil recovery efficiencies. Besides, the results showed that the required operational time as well as the cost of the process directly affects the design of the MEOR process for a selected reservoir. Based on the performed tests, E. cloacae in most of the MEOR scenarios leads to significant tertiary oil recovery efficiencies. Considering the economical parameters B. stearothermophilus SUCPM#14 demonstrated higher feasibility for in-situ MEOR processes compared to the ex-situ type. The proper design of injection protocols and appropriate selection of bacterial formulation result in considerable amounts of tertiary oil recovery.

No literature data are available on the phase behavior of binary or ternary systems involving acetaldehyde, Versatic 10, and Veova 10. This experimental study presents bubble point curves within a temperature range of 295–350 K for the two binaries of acetaldehyde + Versatic 10 and acetaldehyde + Veova 10 at several concentrations. Bubble point data are also presented for the ternary system acetaldehyde + Versatic 10 + Veova 10. The Cailletet equipment was used for the measurements, which operates according to the synthetic method. The measured bubble point pressures increased with increasing temperature and reached up to 3 bar within the concentration and temperature range investigated.

Knowledge of accurate vapor–liquid equilibrium data for mixtures of allyl chloride and 1,5-hexadiene is important for several industrial purposes. The bubble points of binary mixtures of allyl chloride and 1,5-hexadiene have been measured experimentally using a synthetic method. Measurements were carried over concentrations ranging from (0 to 1) mol % of allyl chloride. The vapor–liquid equilibrium is presented at temperatures ranging from (25 to 100) °C. Within this temperature range, bubble-point pressures up to 5 bar were observed. The experimental results indicated that, as the concentration of allyl chloride increases in the mixture, higher pressures are necessary for a complete dissolution of the two components. In addition, solubility pressures increase as temperature increases for a mixture of fixed composition

The high pressure vapor-liquid equilibria of binary mixtures of propylene and isopropyl alcohol were measured experimentally within a temperature range of 315-440 K and pressures up to 6 MPa, using a synthetic method. The experimental data were modeled using the cubic plus association (CPA) equation of state (EoS) by once considering and once not considering solvation between the inert and polar molecules in the mixture. Results indicated that taking salvation into account did not make a huge improvement in the accuracy of CPA for this particular system. In addition, the Soave-Redlich-Kwong (SRK) EoS, representing the widely-used engineering EoS family, was also compared to the CPA. Results showed that both the CPA and SRK perform well for this system in the pressure and temperature range investigated, however, the values of binary interaction coefficients required by SRI( to approach the experimental data are much greater than for CPA. (C) 2013 Elsevier B.V. All rights reserved.

The binary systems of water + biodiesel and ternary systems of methanol + glycerol + biodiesel, which are involved in the biodiesel production process, were investigated in order to find the corresponding equilibrium data. In the case of binary systems, water solubilities in two biodiesels from either corn or frying oil were determined within a temperature range of 297.2–333.2 K. For the ternary mixtures of methanol + glycerol + either corn or frying oil biodiesel, the binodal curves and tie lines were determined at the three temperatures of 293.2, 303.2, and 313.2 K. Results showed that the solubilities in both binary and ternary systems increased with increasing temperature. The Othmer–Tobias correlation was applied to each ternary system to ascertain the reliability of the experimental tie line data obtained, and to provide phase equilibrium correlations at conditions where data are not available. All of the investigated systems were also modeled using the UNIQUAC model. The satisfactory results obtained indicate the suitability of this model for such systems.

The use of ionic liquids is being increasingly investigated in separation technologies, for example, in special distillation processes such as azeotropic or close-boiling mixtures. Such applications require accurate knowledge of the physical properties of the mixtures involved. In this respect, the correlation or estimation of the bubble points might be difficult due to the complex nature of some ternary systems, especially in the presence of ionic liquids. In the present study, the bubble points of several ternary mixtures containing an ionic liquid were correlated using an artificial neural network modeling approach. The solvents investigated consisted of 1-propanol, 2-propanol, ethyl ethanoate, methyl ethanoate, chloroform, propanone, ethanol, methanol and water and the ionic liquids considered were 1-ethyl-3-methylimidazolium trifluoromethane-sulfonate ([emim][CF3SO3]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]). For this purpose, a total of 529 experimental data points from previously published literature were collected to aid in finding the best network architecture and the optimum parameters. To do this, the collected data were divided into two subsets, namely the training and testing subsets. Using the training data set, and based on a trial and error procedure, the optimum network parameters were determined to be three layers including one input, one hidden and one output layer, nine neurons in the hidden layer, the logarithmic-sigmoid transfer function for the hidden layer, and the purline function for the output layer. The optimized weights and biases were also obtained and presented. The feasibility of the proposed network for the correlation of ternary bubble point was then examined using data that were not used in optimizing the network. The overall average absolute relative deviation (AARD %), mean square error (MSE), maximum deviation (Emax), minimum deviation (Emin) and correlation coefficient (R2) were calculated to be 0.20%, 0.9953, −0.97, 0.87 and 0.95, respectively.

In the present study, a mathematical model for naphtha thermal cracking in the presence of steam is developed. This model can predict the behavior of cracking unit of the olefin plant. In this plant a mixture of steam and naphtha passes through cracking tubes. The major role of steam is partial removal of coke that causes different problems along the reactor such as low heat transfer and high pressure drop. In this study another diluting media such as carbon dioxide is employed instead of steam in order to investigate the effect of carbon dioxide on main products yield and operating conditions. Carbon dioxide was shown to improve not only naphtha conversion but also the yield of ethylene and other main products. It also increases the heat transfer to the coils due to the fact that in presence of carbon dioxide the coke thickness along the reactor reduces dramatically. This analysis suggests that the run length of the reactor in presence of carbon dioxide is 25% higher than that in presence of steam. It is also observed that using carbon dioxide reduces tube wall temperature, resulting in less operating and maintenance costs.

In this work a mathematical model is employed to simulate the industrial layered PSA unit of domestic petrochemical plant which operates for purification of hydrogen. The outlet stream of this plant has about 99.99% purity in hydrogen and the hydrogen recovery is about 75%. A good agreement was observed between the simulation results and the plant data. Moreover, in this study, the effect of cycle time and feed flow rate on hydrogen recovery and product purity is investigated and an optimal value is estimated for cycle time and feed flow rate. The optimal sub cycle time causes to reduce the pollution load of the sorbents. Reduction of pollution load of adsorbents increases the absorber life time and consequently, decreases operating cost of PSA unit of domestic petrochemical plant that allocates for purge of adsorbents. The results show that by applying the optimal cycle time and optimal feed flow rate as the operating conditions, hydrogen recovery of the PSA unit increases from 75% to 80% and 77.5% respectively, and hydrogen purity of the product stream slightly reduces. This phenomenon increases purified hydrogen that is fed to hydrogenation unit.

Engineers often demand the availability of easy correlations without difficult and time-consuming calculations. Up till now, there has been a lack of such correlations for mixtures of CO 2 + ionic liquids. This work proposes a correlation to predict CO 2 solubility in 27 common ionic liquids. The main advantages are its simplicity and minimal input data, namely temperature and pressure. The ionic liquids investigated ranged within a variety of families, having various anions and cations. Compared with the popular engineering models of Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK), the present correlation is much easier to use, yet it is also more accurate (PR, SRK and the proposed model had AARD% values of 43.5%, 44.3% and 4.9%, respectively for a total of 3073 data), even when binary interaction coefficients of PR and SRK are optimized to experimental data (AARD% values of 17.2%, 16.9% and 4.9% for PR, SRK and the proposed model, respectively).

In present work, ethylene and hydrogen production is investigated through thermal cracking of ethane in domestic petrochemical plant. In the thermal cracking process, a mixture of ethane and steam is introduced into radiant tubes located vertically in a furnace. The use of steam is mainly due to the partial removal of coke which has undesirable effects on the process. The coke deposition along the tubes causes high pressure drops and also reduction in production yield. In this study, the ethane thermal cracking process of this company is modeled and solved numerically. A comparison between model results and experimental data shows that the model can predict the process accurately. In addition, the effects of using carbon dioxide instead of steam are investigated on coke deposition. According to the results of two cases, the thermal cracking process in presence of CO2 is superior to the conventional process because of higher ethylene and hydrogen productions and less coke thickness. The simulation results reveal that the run length of the reactor in presence of CO2 becomes as twice as the one in presence of steam.

Biodiesel has the potential to become a suitable substitute for diesel fuel in the future. However, the reduction of production costs and finding a permanent oil source have remained the two main concerns for this green fuel. The production of biodiesel from acid oils is one of the ways to reduce biodiesel production costs. In addition, high free fatty acid oils are almost never categorized as edible oils. Consequently, this new material has a more reliable margin in debates concerning the security of food, compared to other oils considered in biodiesel production. By considering these important aspects of biodiesel production technology, this study investigates the pretreatment step of biodiesel production from acid oils. In this work, an oil with high free fatty acid content is selected and the main parameters in the biodiesel production reaction are investigated experimentally. The effects of methanol-to-oil ratio (in the range of 0.2 to 1.2 v/v), the amount of catalyst (in the range of 0.5 to 6% v/v) and time (in the range of 20 to 120 min) on the progress of the reaction are studied.

The high-pressure solubility of hydrogen gas in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulphonyl)amide ([emim][Tf2N]) was measured experimentally in an equipment based on the synthetic technique. Measurements were carried out within a temperature range of 310-450K and pressures up to 15 MPa. Hydrogen solubility was shown to be low in this ionic liquid, reaching a maximum concentration of about 6 mole percent at the highest temperatures and pressures investigated. Hydrogen solubility showed an "inverse" temperature effect, indicating increased solubility at higher temperatures in contrast to other commonly investigated gas solubilities in ionic liquids, such as carbon dioxide. Within the temperature and pressure range investigated, solubility isotherms on a pressure-concentration diagram approximated linear behaviour. It was also shown that the solubility of hydrogen increases as the alkyl side chain of the cation increases in size within the homologous family. (C) 2012 Published by Elsevier B.V.

In the present study, a new optimization procedure is applied on Fischer–Tropsch synthesis (FTS) reactions to maximize the production yield of gasoline ( C 5 + ). In this way, the conventional synthesis reactor has been discretized into some elements. For each element, the inlet temperature, the injected hydrogen and the removed water are considered as decision variables. Then, the optimum amount of these decision variables is defined by using the differential evolution (DE) algorithm as an optimization method. Five distinct discretized reactor (DR) models have been investigated: the optimum inlet temperature of each element in DR1, the optimum hydrogen injection into each element in DR2, the optimum water removal from each element in DR3, the simultaneous optimum inlet temperature and hydrogen injection in DR4 and the simultaneous optimum inlet temperature, hydrogen injection and water removal in DR5. In all of these models, the objective function was the production yield of C 5 + at the end of the reactor. The results of this theoretical study demonstrated that in comparison with conventional reactor (CR) the C 5 + yield, in DR1–DR5 is increased up to 4.7, 46.7, 2.0, 54.2 and 57.7 percent respectively.

In this study, the dehydrogenation of cyclohexanol (CLL) and its utilization in a novel thermally coupled reactor for Fischer–Tropsch synthesis (FTS) has been investigated. In the new configuration, the produced heat of FTS reactions is removed by the endothermic reaction of CLL dehydrogenation instead of circulating high-pressure boiling water in the conventional reactor (CR). The products of this reaction are hydrogen and cyclohexanone (CLN). Some of the generated hydrogen is utilized in synthesis gas and also in hydro cracking unit for production of GTL products and other is stored and used in some other processes. Gasoline ( C 5 + ) – the desirable product – alongside some undesirable products like carbon dioxide and methane are produced in FTS reactions. To demonstrate the superiority and advantages of this new configuration it has been compared with another thermally coupled reactor for FTS in which the dehydrogenation of cyclohexane works as coolant reaction in the endothermic side of the reactor. In order to analyze this novel reactor a one-dimensional heterogeneous model has been applied. After modeling and solving the differential equations, the excellence and advantages of new configuration are clarified. The ( C 5 + ) yield is increased and a reduction in the generation of undesirable products like CO2 and CH4 is observed in this new configuration. Moreover, hydrogen and CLN which both are useful products are generated in considerable amounts in the endothermic side of the reactor.

During biodiesel production, the product is contaminated with impurities such as some non-reacted alcohol, glycerol, and catalyst. In order to comply with product requirements, these impurities must be removed, for example, by washing with water. Knowledge of the extent of water solubility in biodiesel is required to design the drying system and determine fuel quality. In the present work, the solubilities of water in biodiesels produced from sunflower and canola oils were measured within the temperature range of 24–60 °C. The solubility of water increased with increasing temperature and biodiesel unsaturation. The liquid–liquid equilibria of ternary systems of glycerol, methanol, and the above-mentioned biodiesels were investigated experimentally at 20, 30, and 40 °C. The binodal curves were determined by using the cloud point titration method and the tie lines were measured by evaporating the methanol. Both binary and ternary data were modeled using the UNIQUAC model. The model showed good agreement with the data. Othmer-Tobias correlations were applied and the corresponding constants were obtained. The results validated the consistency of the tie-line data obtained experimentally.

On the basis of an artificial neural network (ANN), a model is proposed to predict the thermal conductivity of pure ionic liquids. A total of 209 data points from 21 different ionic liquids was used to train and test the proposed network. The optimum number of hidden layers was determined to be 1, with 13 neurons in the hidden layer and logarithmic–sigmoid and purelin functions as the transfer functions in the hidden and output layers, respectively. The results obtained reveal that the proposed network is able to correlate and predict the thermal conductivity of all of the pure ionic liquids with an overall absolute mean relative deviation percent (MARD %) of 0.5% and mean square error (MSE) of 1.2 × 10–6. The optimized network was also compared with literature correlations and a predictive group contribution method. The results indicate the rather good accuracy of the proposed neural network compared to the previously proposed literature methods.

Liquid–liquid phase equilibria of two systems of concern in the biodiesel production process are determined experimentally. The first system is the binary mixture of water + biodiesel within a temp...

Accurate knowledge of gas solubility is necessary for the development of processes involving ionic liquids (ILs) and gases. In this work, a group contribution approach is used to predict the phase behavior of CO 2 + IL systems based on the statistical associating fluid theory (SAFT-γ) as proposed by Lymperiadis et al. The IL molecule is divided into groups of CH 3 , CH 2 , cation head, and the anion. The SAFT-γ parameters of CO 2 + imidazolium-based ionic liquids with either [PF 6 ], [BF 4 ] or [Tf 2 N] anions are optimized to experimental data. The ability of the model to describe the phase behavior of these systems is demonstrated within a temperature range of 313.15–353.15 K and pressures up to 100 bars. Moreover, by using the optimized group parameters, the performance of the model is examined by predicting equilibrium data of some CO 2 + IL systems not included in the optimization database. The results show good agreement with experimental data.

Previously unavailable high-pressure solubility data of hydrogen in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide has been measured experimentally up to temperatures and pressures of 450 K and 15 MPa, respectively. In contrast to CO2 solubility, H2 tends to dissolve better in the ionic liquid at higher temperatures. This “inverse” temperature effect has been studied from a thermodynamic perspective and the underlying reason for this effect is explained. It is shown that the negative P-T slope is not limited to this particular binary mixture, but is the typical behavior in most, if not all, H2 + ionic liquid systems. However, there is a certain range of temperatures, pressures, and concentrations in which this phenomenon occurs. By predicting the Scott-van Konynenburg phase diagram for systems of H2 + ionic liquids to be of type III, it is shown how and why the solubility increases with temperature in some regions, but decreases in others. © 2012 American Institute of Chemical Engineers AIChE J, 2012