فهرست مطالب mansour jahangiri

Considering the limitations of energy consumption and the increasing problems of pollution from low-quality fossil fuels and the need to increase the quality of these fuels by using oxygen additives such as Ethyl tert-butyl ether (ETBE) for their combustion, reviewing and optimizing the production processes of oxygen additives is of great importance. The goal of this study is to simulate-optimize the ETBE production which is used as an oxygenate gasoline additive in the production of gasoline from crude oil. The feed for the ETBE unit comprised two flows of hydrocarbon and ethanol. The Soave-Redlich-Kwong (SRK) equation of state for the vapor phase and the UNIQUAC activity coefficient model for the liquid phase have been used. In this work, at first, the reactive distillation process was simulated by HYSYS software for producing ETBE. Then, the coding was written using MATLAB software and the Genetic algorithm (GA). Both software have been linked simultaneously and the later optimization data was transferred and compared with HYSYS data. The objective function was reflected as the total annual income of ETBE production. The parameters of the objective function were optimized by GA. Optimization was made on decision variables of the objective function which included the output stream temperature of the heater (Tho), input stream temperature of the reactive distillation tower (Tti), output stream temperature of the cooler (Tco), and input stream feed pressure of the distillation tower (Pti). The results of GA optimization show that reboiler duty decreases by 10% as well as total annual profit increases by 15%. Additionally, the comparison of the present work with the findings of researchers reveals a good agreement.

In this research, a photocatalytic reactor made of quartz was designed and built. Then ZnO nanophotocatalysts modified with different percentages of Ag and Zr were synthesized by combustion method and using microwave. Photocatalytic experiments showed that nanophotocatalysts with a mass ratio of 0.093 Ag and 0.04 Zr are more efficient. The characteristics of this catalyst were evaluated by XRD, SEM and FT-IR analyses. Then the photocatalytic activities of ZnO-Ag-Zr in the degradation of reactive red dye 198 were investigated and the effective factors such as pH of the solution, amount of catalyst and initial concentration of the solution were investigated. Experiments showed that the optimal conditions for decolorization of the dye at a concentration of 20 mg/liter are: pH=10 and the amount of catalyst is 0.3 g/liter, and under these conditions, decolorization is above 92%. Also, in the study of the kinetics of the aforementioned reaction, it was shown that the removal rate of Reactive Red 198 dyes is in good agreement with the pseudo-first-order Langmuir-Hinshelwood equation, and therefore, the kinetic parameters were determined using this model.

The Zeolitic adsorbent is successfully synthesized by natural Iranian kaolin to the separation of hydrogen sulfide from a gas mixture. In this work, zeolite 13X from modified natural Iranian kaolin at 65 °C for 72 h at various concentrations of caustic soda solution was synthesized using a metakaolinization process at 900 °C for 2h. By Taguchi’s experimental design, the best duration and temperature of crystallization were 72 h and 65 °C. Prepared zeolite 13X was characterized using X-Ray Diffraction (XRD), Fourier Transforms InfraRed (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM), and N2 adsorption-desorption methods. In addition, the adsorption capacity of zeolite 13X for 310 ppm of hydrogen sulfide mixed with hydrocarbon gas-like butane was investigated using a volumetric method by two different detectors and different temperatures. After the adsorption process, the amount of H2S in output gas was about 108 ppm and this confirms approximately more than 65% adsorption at 25 bar and 298K. The results are is in good agreement with experimental results.

Asphaltene formation and precipitation in crude oil is an extremely serious issue. The most important way to combat this problem in the petroleum fields was using chemical solvents like xylene. This solvent has a lower environmental impact and safety in the extraction process. The purpose of this study was to find an alternative solvent such as aromatic solvent, especially xylene, employing new water-based emulsions. The prepared solvents containing 50-60% water, 30-35% aromatics solvents (xylene, toluene,…), 3-5% co-solvent (kerosene, gasoline, ethanol…), and less than 1% surfactant. In this research, five different kinds of emulsion solvents with various compositions were prepared. Then the tests were achieved at the environmental and oil well (80°C) conditions. The temperature growth was increased the asphaltene solubility in all prepared samples in this study. Also, the results of the experiments on aqueous emulsion solvents show that these solvents have high performance leading to good comparability with aromatics solvents like xylene and toluene. Therefore, the harmful aqueous aromatic solvents can be replaced and reduced harmful effects with suitable aqueous emulsions in the petroleum industries.

Mixing tanks equipped with mechanical stirrer are broadly applied in chemical and petrochemical industries, due to their variety of industrial process requirements. In this study, helical single blade mixer was designed applying CATIA and then mixing of fluid and solid particles, in a tank with this agitator was examined by OpenFOAM. For velocity distribution in the mixing tank, continuity, momentum equations, boundary conditions and coding were performed applying​ C++ language scripts in the software. The results of velocity distributions in three directions coordinates indicated that the efficiency of helical blade mainly correlated to axial and tangential flows.  The radial flow has less important role in mixing operation. Moreover, solid particles concentration distribution were computed in the fluid phase .It was exhibited that the particles were distributed homogeneously in the tank. In addition, temperature distribution was obtained applying continuity, momentum and energy equations as well as utilizing necessary code and boundary conditions in the software. Consequently, a correlation for Nusselt number as a function of Re, Pr and Vi was acquired by using temperature profile and dimensional analysis. The results achieved are in good agreement with those available in literature.

The electrochemical coagulation process, or EC, is an electrochemical process that direct electrical current was used to remove pollutants from solution. In this paper, the effect of nanofluids of iron, copper, and zinc metal oxides on electrochemical reaction of heavy cobalt metal removal from the refinery wastewater was investigated. Different tests were performed to achieve the best performance with maximum efficiency. In the meantime, the best performance was achieved at 30 volts and 60 minutes having efficiency up to 52%. In the next step, the tests were performed using iron, copper, and zinc nanoparticles oxides that they could been reduced cobalt values to 73%, 87% and 61% of the initial amounts, respectively. Between used metal oxides, the results show iron oxide nanoparticles could reached to maximum cobalt removal from the wastewater, and after that copper and zinc oxides nanoparticles have high removal efficiency, respectively. Surface response method used to determining the optimum cobalt removal conditions. A quadratic statistical model was presented in terms of experimental parameters. The statistical model predictions from experimental design are in good agreement with experimental data for cobalt removal in this work.

A high chlorinated alumina catalyst obtained by treating Pt/γ-Al2O3 (0.25 wt. % Pt) samples with two mixtures of CCl4/N2 and CCl4/N2/H2 was tested for the hydroisomerization of C6 alkane. The conversion of n-hexane feed was diluted with hydrogen performed with different H2/HC ratios at various temperatures, liquid hourly space velocities (LHSVs) and 3MPa total pressure. The catalyst introduced in the reactor displayed a fairly high initial activity, but conversion slowly declined with time on stream. Adding CCl4 to the hexane feed could not improve the stability with time on stream. The effects of temperature on conversion and isomer selectivity were studied at various H2/HC ratios and LHSVs. Superior conversion and selectivity were found for the catalyst at 160 ˚C and 120 ˚C at LHSV 1.2 h-1. Furthermore, effects of LHSV and low temperature were studied on conversion and product octane number derived from hexane isomerization, respectively. The highest octane number was observed at the low space velocity (1.2 h-1).

Silicon and aluminum sources are most important reactants in the synthesis of zeolite. The use of the silicon source has an important effect on the crystallization of zeolites. Also, it can change the properties of the end product. This work reports the influence of three common commercial silica sources such as colloidal silica (Ludox AM-30), fumed silica and water glass on the crystallinity of NaX zeolite by hydrothermal method, also the adsorption of carbon dioxide on these samples have also been studied. The synthesized samples from different sources are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transformin frared (FT-IR) and nitrogen adsorption–desorption analysis. The sample obtained by fumed silica, colloidal silica and water glass is NaX phase. The percentage of crystallinity and surface area increased in the sequence: water glass

Precipitation and deposition of asphaltene are one of the serious problems in oil industry and has drawn the attention of many researchers in recent decades. The application of aromatic solvents is the most common method of asphaltene removal, especially in oil wells. Xylene, one of most applicable aromatic solvents, creates many environmental issues. Then it is needed to reduce the use of xylene either by co-solvents or replace it with environmentally friendly solvents. The main purpose of this paper is to find an alternative solvent to replace or reduce consumption of aromatic solvents. Firstly, the efficiency of xylene has been evaluated in the presence of co-solvents including kerosene and diesel at different temperatures. Then, terpene as an environment-friendly asphaltene solvent has been studied at ambient temperature and 80 ⁰C. The results show that efficiency of xylene in the presence of kerosene is higher than diesel. Moreover, temperature increase leads to more asphaltene dissolution. Finally, terpene has shown an acceptable solubility compared to aromatic solvents while its efficiency is being reduced dramatically in the presence of kerosene and diesel.

This study investigated the photo-degradation of methyl orange (MO) as a type of azo dye using a CuO/α-Fe2O3 nanocomposite. A CuO/α-Fe2O3 powder with a crystalline size in the range of 27-49 nm was successfully prepared using simple co-precipitation along with a sonication method. The characterization of the synthesized sample was done via XRD, FE-SEM, EDS, FTIR and DRS analyses. The Tauc equation revealed that the band gap of the nano composite in the direct mood was 2.05 ev, which is in the visible light range. The effect of operating factors containing dye concentration, photocatalyst dosage and pH on dye degradation efficiency was measured. Response Surface Method (RSM) was employed to specify the parameter effects. The photocatalytic activity of the CuO/α-Fe2O3 nanocomposite was evaluated by degradation of MO under visible light irradiation. The results showed that the pH value played a very effective role in the dye degradation process efficiency. Also, the photocatalytic degradation of MO obtained was equal to 88.47% in the optimal values.

In this study, MnO2 nanowire adsorbent was synthesized by low cost preparation method that was capable of extracting gold form diluted jewellery waste water solutions. Different adsorption parameters like number of treatment, hold time, pH and agitation speed of mixing on the gold adsorption were studied. Adsorption experiments was designed by Taguchi method and effectiveness of parameters as well as optimum operating conditions were determined. The manganese oxide adsorbent, prepared by low-temperature synthesis followed by acid treatments, exhibits a nanowire like morphology. The results showed that under the optimum operating condition, gold adsorption efficiency was more than 77.2% during 2h.

The multiple reference frames (MRF) method is the most suitable method to simulate impeller rotation in mixing systems. Precise determination of stationary and moving zones in MRF method leads to accurate results in mixing performance. In this research, the entire volume of mixing system was divided into two zones. The kinetic energy values were used to distinguish the zones with different velocities. The low-velocity zones, close to zero, were considered as the stationary zone and higher velocities were considered as the moving zone. The standard geometrical parameters were used for mixing system. The axial velocity and axial flow number were compared with literatures for validation. The values for dimensionless diameter of stationary zone at different Reynolds numbers were achieved for Newtonian and non-Newtonian fluids that are in agreement with
values applied in literatures. The results show that the dimensionless diameter of stationary zone decreases as Reynolds number increases.

Anthocyanin is known as natural pigments of fruits. These pigments are among the best natural pigments to be used in food industry. In this study، the method for extraction of cherry’s pigment (Anthocyanin) using an Amberlite XAD-7 resin is discussed. Amberlite XAD-7 has got an excellent condition for extraction of Anthocyanin due to its lack of charged groups and great porosity. After completion of adsorption process of Anthocyanin on Amberlite resin، desorption process was performed by acidic methanol which was able to extract about 90 percent of Anthocyanin compounds. Furthermore، Langmuir and Freundlich isotherms were applied for explanation of Anthocyanin adsorption which finally indicated that Langmuir model has a better consistency

One of the basic problems in the mixing of non-Newtonian fluids and especially diluted polymer solutions is the determination of the prevailing shear rates during the mixing process. The significant method of Metzner and Otto for calculation of the effective shear rate is limited to the laminar region and it is not valid in the transition region. In this article, the local shear rate and the Metzner-Otto method for helical ribbon impeller have been studied using laser Doppler anemometry (LDA) for viscoelastic liquids. It is also shown that the variation of the local shear rate against the impeller speed is better correlated by a power equation, i.e., γ = k´s.Nb´ in the transition region, i.e., 70 < Re < 6700. In addition, a correlation between the improved coefficient, k´s, and the elasticity number of the viscoelastic liquid is given that can be helpful in designing the mixing of viscoelastic as well as inelastic non-Newtonian fluids by means of relating the rheological properties to the kinematical and dynamical parameters of the mixing process.

Velocity profiles are helpful for the confident design of mixing tanks in the transition region. In this article, velocity profiles for helical ribbon impeller have been studied using laser Doppler anemometry for viscoelastic liquids with rheological properties typical of those found in polymer processes. Local tangential and radial velocities were measured at radial positions on a horizontal plane passing through the middle of the helical ribbon impeller. New correlation is suggested for dimensionless local tangential velocity profiles in the transition region, i.e. 70

The hydrodynamics of the flow in stirred-tank reactors, i.e., velocity profiles, stress fields, turbulence characteristics and etc., are essential for the confident design of mixing tanks. fluctuation tangential and radial velocities were measured using a two-component laser doppler anemometry (LDA) system for a typical Rushton turbine impeller. The working fluids had different concentrations of polyacrylamide (PAA) with rheological properties typical of those found in polymer processes. It is shown that the correlations for fluctuating velocities in Newtonian fluids do not apply to the case of viscoelastic liquids. New correlations are given in the lower part of the transition region, i.e., 30 < Re < 2000, for fluctuating tangential and radial velocity components values along the centre line of the impeller tip.

Velocity profiles are helpful for the confident design of mixing tanks in the transition region. In this work, mean and fluctuating tangential and radial velocity components were measured using a two-component laser doppler anemometry (LDA) for a typical Rushton turbine impeller. The working fluids were different concentrations of polyacrylamide (PAA) solutions with rheological properties typical of those found in polymeric processes. It is shown that the correlations for mean and fluctuating velocities of Newtonian and inelastic non-Newtonian fluids do not apply to the case of polymeric viscoelastic liquids. New correlations are given in the lower part of the transition region (i.e., 35