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In this study, physical properties of nanofluids such as viscosity and thermal conductivity are investigated. Although there are many experimental and theoretical correlations and models available to predict these parameters, predictions are highly conflicting because the involved mechanisms are not fully understood. For instance, the predicted values of dynamic viscosity of γ-Al2O3/water nanofluids (at a volume fraction of 0.001) by different models range between 0.0005623 and 0.0403 kg/m.s and thermal conductivity ranges within 0.866 and 1.551 W/m-K under the same conditions. In this work, 184 experimental data of thermophysical properties of various metal oxide nanoparticle including Al2O3, SiO2, TiO2, Fe2O3, MgO, and CuO at a temperature range of 30 to 65 °C, diameter range of 10 to 50 nm, and volume fraction between 0.004% to 2% were collected from various publications. In this work, artificial neural network (ANN) has been implemented. The parameters of thermal conductivity and dynamic viscosity have been correlated to nanofluid concentration, temperature, particle size and molecular weight. It has been found that the topography of (4, 4, 4) from the ANN provides about 2% and 1% cross-validating and testing error respectively. Additionally, a sensitivity analysis was performed and the effect of individual parameters was analyzed. [ABSTRACT FROM AUTHOR]

Frontal polymerization is a relatively old polymerization process that is performed in a limited space and is done with a spontaneously progressive wave mechanism. This process is for quick and easy preparation of all types of polymers, co-polymers, nano composites, large composite parts. In recent years, it has been used to prepare polymer hydrogels. This study is an overview of frontal polymerization in the chemical industry. Hydrogels are a group of lattice polymers with a three-dimensional structure, which, due to their hydrophilic groups, are able to absorb large amounts of water and biofluids without dissolving. SO3H-in the structure of hydrogels. These materials can absorb from 10% to thousands of times their initial weight in the dry state of water. The water content of hydrogels plays an important role in determining the overall properties of the polymer network. For this reason, compared to hydrophobic polymer networks, hydrophilic hydrogels show different properties. Also, the preparation conditions of hydrophilic hydrogels are milder due to the formation of gels at room temperature and the rare use of organic solvents. [ABSTRACT FROM AUTHOR]

Removal of pollutants from petrochemical effluents is vital in terms of effluent control and achieving environmental standards. Because of the nature of particular effluents in petrochemical industry, direct biological treatment is not recommended. Therefore, novel techniques such as advanced oxidation processes through photocatalytic processes have been proposed for this purpose. In this study, synthetic photocatalyst TiO2-CTAB (cetyletrimethylammonium bromide) was used for treatment of a real spent-neutral effluent from a neutralization section of the olefin unit of a petrochemical plant. In order to study the chemical oxygen demand (COD) of the process, a double-walled photoreactor was utilized pursuing the Box-Behnken experiment design method. The results show that increasing the concentration of photocatalyst at neutral pH, up to an optimal value of 0.61 g/L in unrestricted conditions and 2 g/L in restricted conditions enhances COD removal by 91.3% and 90.7%, respectively. Furthermore, the effects of oxidation parameters, aeration rate, pH and the amount of catalyst loaded on COD removal efficiency were investigated. It is interpreted from the results that when the oxidant is at its lowest level, removal efficiency is reduced with increasing pH. [ABSTRACT FROM AUTHOR]

According to the studies, increasing the injection pressure at the surface will not have much effect on increasing the production flow of the well therefore, taking into account the economic cost, making changes to increase the injection gas pressure is not justified. Increasing the injection gas flow rate will cause a significant increase in the production flow. Therefore, it is recommended that control valves cannot be installed in order to control the injection flow gas due to the operational limitations, by installing appropriate reducers in the injection flow gas path to increase the oil flow. In order to investigate the effect of increasing injection gas flow rate on production from one well, one injection of gas with flow was performed at about 12000000 SCF / DAY and again injection rate was increased to 15000000 SCF / DAY and then the results were compared. [ABSTRACT FROM AUTHOR]

In order to clarify the situation in energy consuming devices in hydrocarbon plants (Olefin, butadiene and butene1), by using thermodynamic laws (1st and 2nd) and apply energy and exergy balances to all equipment's, loss rate and the amount of renewable energy for each group of equipment such as pumps, towers, heat exchangers and ... were calculated and with the process changes, it was tried to utilize current energy as much as possible. Since the irreversibility's cannot be omitted completely in processes, the rate of energy loss was reduced as much as possible by change in operation condition. Finally, the factors that influence the creation of irreversible processes have been discussed. [ABSTRACT FROM AUTHOR]

Corrosion reactions are often complex heterogeneous reactions that are accelerated by interactions such as: common kinetic considerations, electrolyte chemical composition, mass transfer between the electrolyte and the metal surface, Different surface effects such as adsorption, desorption and surface hardness are determined. The interactions between these factors make it difficult to reproduce electrochemical data or precise conditions that cause a metal to be corroded. These are the experimental factors that must be considered when corrosion tests are being designed. Ignoring these factors can produce data that does not provide the true corrosion behavior of the test metal under study. This paper presents the relationship between the inherent errors of corrosion measurement and suggestions on how to handle variability of electrochemical data. [ABSTRACT FROM AUTHOR]

The absence of high degrees below zero in most part of Iran, especially in the Persian Gulf area, provides suitable conditions for the replacement of thermodynamic inhibitors with kinetic inhibitors. Although it is possible to use kinds of LDHIs (Low Dosage Hydrate Inhibitor), especially kinetic inhibitors in most parts of Iran, it is always necessary that the limitations of these materials are checked before using. Hydrate is an aqueous network with a set of empty spaces in a small distance. If some of this space was filled by gas molecules, the hydrate could be considered as a stable solid. In other words, gas hydrates are complex crystalline molecules that are formed from the mixture of water and suitable gas molecules. [ABSTRACT FROM AUTHOR]

In this study, the kinetics of gas hydrate formation in the presence of tetra-n-butyl ammonium fluoride (TBAF) and cetyl trimethyl ammonium bromide surface active ingredient (CTAB) with zinc nano oxide (ZnO) are investigated and the most important kinetic parameters of hydrate formation such as their induction time and storage capacity were measured. The kinetic experiments were carried out in a constant volume temperature method in a high pressure reactor. The storage capacity of carbon dioxide hydrate in water in the presence of ZnO and surfactants at different temperatures, pressures and concentrations of TBAF and CTAB additives was calculated and measured using time induction measurements. The results show that with increasing pressure and decreasing temperature, the storage capacity of CO2 in hydrate increases. Finally, statistical analysis of the parameters affecting the induction time of hydrate formation showed that zinc oxide can reduce the induction time of hydrate formation compared to other additives. [ABSTRACT FROM AUTHOR]

In the present study, a new nanocomposite of iron/cobalt oxides and magnetic nanoparticle doped with polyaniline (PANI‐Co3O4@MNPs) was synthesized and subsequently, evaluated for its potential in decontaminating nitrate ions from ground water. Various important parameters such as pH, mass dosage, adsorption time, initial concentration, and temperature were experimentally investigated. The important surface and chemical properties of PANI‐Co3O4@MNPs, such as surface morphology and roughness, composition and chemical structure were evaluated using field emission scanning electron microscope, energy‐dispersive X‐ray spectroscopy, and Fourier transform infrared. Finally, the removal of nitrate was assessed using kinetic, adsorption isotherm, and thermodynamic studies to investigate the underlying mechanism of the removal process. Maximum adsorption capacity was found to be 68.96 mg/g for nitrate ions at pH 6, adsorbent dosage 60 mg within 60 min. The kinetic studies and the adsorption isotherms have been well fitted using pseudo first and the Freundlich models respectively whereas the thermodynamic parameters have been described in terms of enthalpy, entropy, and Gibbs free energy which showed a negative value signifying that the adsorption process was exothermic and spontaneous in nature. [ABSTRACT FROM AUTHOR]