alireza azimi

In this study, direct conversion of methane to methanol in the plasma process was attended. Besides, RSM modeling was used to optimize and evaluate parameters such as voltage, the flow rate of CH4, Ar, and external electrode length. RSM prediction model by the desired condition including minimized Ar (20 mL/min), O2 (2 mL/min), CH4 (2 mL/min), and voltage (4 kV) was used to determine the effect of Ar and CH4 in reactions. The results showed that increasing the Ar flow from 20 to 100 mL/min led to less methanol mole percent. On the other hand, enhancement in methane flow rate from 2 to 12 mL/min was the reason for raising the methanol mole percent at the reactor outlet. To determine how modifying the length of the external electrode affected the mole percent of methanol, the length was lowered from 12.5 to 2 cm, clearly reducing the amount of methane converted. However, it was effective in raising the methanol mole percent to 3% in E.EFF 0.13 mmole/kJ and length of electrode 4 cm. As well as the methanol mole percent in the least energy efficiency E.EFF 0.045 mmole/kJ detected at 2.27%. To summarize, in DBD plasma reactor by direct conversion of methane, increasing in voltage and Ar flow rate had a significant influence on the progress of the process which had an unfavorable effect on methanol mole percent. Meanwhile, the enhancement of CH4   flow rate had an impressive effect on the raising of methanol. Furthermore, the influence of oxygen flow was negligible.

Emerging consequences due to the expansion of urbanization, unfair distribution of wealth, facilities and services on the one hand, and the poor state of the economy, unemployment and the consequent reduction in government revenues, which leads to a reduction in the support of organizations for vulnerable people, on the other hand, have affected the social hope of citizens.using sociological theories, we tried to find the factors affecting social hope among Tehrani citizens, and five variables were obtained from theories to explain the causes of social hope, including life satisfaction, social security, feeling of powerlessness, social trust, and social inequality. The research method is a quantitative-survey type and the sample showed that all five independent variables had an effect on the social hope of Tehrani citizens, which according to the correlation coefficient, With the increase of social trust, social security and life satisfaction, the level of social hope also increases, but on the other hand, with the increase of the feeling of powerlessness and social inequality, the level of social hope will decrease. In addition, the results of direct, indirect and total standard coefficients in structural equations showed that the variables of life satisfaction and social inequality, in addition to the direct and significant effect on the variable of social hope, have an indirect and significant effect through the mediation of the three variables of social trust, social security And they also feel powerless.

According to financial and monetary theories, the main role of banks in the economy is to create liquidity through cash deposits and provide them in the form of loans. The main purpose of this study is to investigate the effect of shadow banking system on the volume of liquidity in Iran. For this purpose, Iranian quarterly data during the years 1397-1388 have been analyzed using structural vector autoregression and ordinary least squares. The results of  the SVAR model in the form of shadow banking shock and analysis of variance show that the shadow banking system affects the liquidity of the country in the period under review, so that the effect of shadow banking shock on supply Money and quasi-money reached their highest levels in the second year, about 29.70 and 28.40 percent, respectively, and then began to decline. Also, the results of the ordinary least squares method show that there is a positive relationship between shadow banking and money supply and quasi-money and the correlation coefficient of shadow banking with money supply and quasi-money is 0.502677 and 1.043699, respectively. Therefore, the activities of the shadow banking system increase the volume of liquidity by promoting the volume of money and quasi-money, which are the components of the volume of liquidity.

In this study, the effect of changes in plasma generator voltage on the partial oxidation reaction of methane in a DBD plasma reactor and in three states without catalyst, plasma with nickel oxide catalyst, and plasma with copper oxide catalyst was investigated. The results showed that increasing the device voltage from 6 to 10 kV with nickel catalyst increased the molar percentage of methanol from 0.37 to 0.76% and for C₂ + hydrocarbons from 0.55 to 1.8%. Plasma and copper catalyst testing decreased the production of precious hydrocarbons as the voltage increased. Hence, the molar percentage of methanol declined from 0.3 to 0.18, and the molar percentage of C₂ + diminished from 0.82 to 0.23. Calculation of energy consumption when increasing the device voltage showed that the experiments were performed at 6 kV voltage with a higher energy efficiency of 0.17 mmol/ kJ. At this voltage and in the presence of a nickel oxide catalyst, the selectivity of carbon monoxide was 37% and hydrogen was 58%, which was higher than the other two and the amount of H₂ / CO in the synthesis gas was closer to 2. To sum up, the choice of nickel catalyst in the DBD plasma reactor to produce precious hydrocarbons or synthetic gas with lower energy consumption is better than copper catalyst and non-catalyst plasma.

The aim of this study was to investigate the effect of interlayer on the microstructal characteristic and mechanical properties of diffusion welding between 17-4PH precipitation hardening stainless steel and Ti6Al4V alloy. For this purpose, the bonding of two alloys without the interlayer and with the pure nickel interlayer at a temperature of 900 ° C and a time of 45 minutes was investigated. . The structure of joints were characterized by optical microscopy, scanning electron microscopy and energy dispersive x-ray spectroscopy. After examining the microstructure and diffusion rate, the hardness and shear strength of joints were also investigated. The results show that the β-Ti, λ + FeTi and σ phases are formed at the interface when the interlayer is not used.The formation of these intermetallic compounds causes a brittle bond and reduces the mechanical properties. When the pure nickel interlayer is used, Ni3Ti, NiTi and NiTi2 intermetallic compounds are formed at the nickel-titanium interface. Nickel in the form of interlayer prevents the diffusion of titanium into iron and the formation of FeTi compounds. The maximum microhardness of 562 Vickers was obtained, which is exactly on the intermetallic compounds. The average shear strength was 289 MPa if the interlayer was used.

The flow patterns and pressure gradient of a two-phase mixture of water/super high viscous oil in a horizontal pipe were experimentally investigated. The mixture containing oil with a viscosity of 67 cP and density of 0.872 g/cm3, and pure water flows through an acrylic pipe with a length of 6m and a diameter of 20 mm. Superficial velocities of water and oil were in the range between 0.18–1.2 m/s and 0.18–0.95 m/s, respectively. Six flow patterns were identified. The stratified flow became visible at low velocities of oil (<0.42 m/s) and water (<0.26 m/s) and bubbly flow patterns happened at low superficial oil velocities (Uso = 0.18–0.22 m/s). The dispersion of oil in water (DO/W) occurred at high superficial water velocity (Usw =0.79 – 1.2 m/s) at low or moderate superficial oil velocities (Uso = 0.18 –0.53 m/s). Dispersion of water in oil (DW/O) appeared from superficial oil velocity of higher than 0.69 m/s. The effect of oil viscosity on flow structure was assessed by comparing the present work with the available data and this revealed that the extent of dual continuous patterns reported by other systems containing low viscosity oil is 5% higher than the results of the present study. The effect of oil viscosity on the pressure gradient was also investigated. The pressure gradient values obtained in this study were 80% greater than other studies at similar superficial oil and water velocities. The experimental pressure gradient was also compared with the values predicted by the Al-Wahaibi correlation and two-fluid model. The Al-Wahaibi correlation agreed reasonably with the experimental results, with an average absolute error of less than 9%, while the error of the two-fluid model was 30%.  Based on the results, a clear overview of the flow patterns and pressure drop with detailed information was presented.

In this study, the effect of various concentrations of alkyl polyglycoside (APG), aluminum oxide nanoparticles (Al2O3), and tetra-n-butyl ammonium chloride (TBAC) on the storage capacity of CO2 hydrate formation are investigated. For this aim, a laboratory system is developed. The experiments are carried out in the pressure range of 25 to 35 bar and the temperature range of 275.15 K to 279.15 K. The Experimental results showed that by increasing the system pressure at a constant temperature, the storage capacity increased by 48% on average. Decreasing the system temperature at constant pressure increased the storage capacity by 23% on average. Adding APG to the system at constant temperature and pressure increases the storage capacity by 75% on average, while adding nanoparticles of aluminum oxide increases the storage capacity by 5% and TBAC 38% on average. For statistical analysis of laboratory data, Design-Expert software and Response Surface test design method, and Quadratic model are employed and a mathematical relationship is developed with R2 = 0.9987 to estimate CO2 storage capacity in hydrates. The optimum amount of storage capacity equal to 137.476 has been reached at 34.558 bar, 276.085 K, 2.825 wt% of TBAC, 956.733 ppm APG, 2.436 wt % Al2O3.

In the present study, a hybrid method has been used to completely removal these compounds. This method is a combination of 3 different separation processes including ultra-filtration, fixed bed adsorption and Nano filtration. The membranes used were made by Sepro USA and were made of Polyacrylonitrile and polyamide with 0.0162 and 0.0165 cm thickness and 0.05 and 0.003 μm pore sizes, Ultra and Nano types were used, respectively. The results showed that none of these processes alone can reduce the concentration to the standard level and eliminate them completely. The results of the hybrid combination of these processes showed that the use of ultra-filtration at the beginning and as a pretreatment increases the flux and thus increases the treatment rate. In general, the use of this combined method increased the speed of the treatment operation, reduced the choking rate and had a higher efficiency of the treatment operation. The results obtained from the study of adsorption models showed that the adsorption of halostonitriles on adsorbent particles is conform with the temkin equation. Optimal adsorption conditions of halostonitriles in continuous adsorption operation were obtained in a tower with a diameter of 1.6 cm with an adsorbent height of 75 cm. None of the methods of removal of ultrafiltration, adsorption and Nano filtration alone, even at low feed concentrations, could not approach the standard of the World Health Organization, the standard of the Ministry of Health of Iran and the European standard in the product of permeation.

Pressure gradient of a two phase mixture in a horizontal pipe were experimentally investigated for water/super viscose oil mixtures. The mixture contained oil having a viscosity of 67 cp and density of 0.872 g/cm3, and pure water, flowing through an acrylic pipe having a length and diameter of 6 m and 20 mm, respectively. A high speed digital camera has been used to record visual information. Superficial velocities of water and oil were in the range between 0.18–1.2 m/s and 0.18–0.95 m/s, respectively. The experimental pressure gradient has been compared to the Al-Wahaibi correlation and two-fluid model. The absolute average error for the “two-fluid model” and Al-Wahaibi correlation have been calculated for 30% and 12%, respectively. In this investigation, a new modified correlation is developed on the basis of the Al-Wahaibi correlation, that predicts the values of pressure gradient with an absolute average error of about 9%. The pressure gradient correlation was validated extensively against 11 independent data sources. To our knowledge, this is the best pressure gradient furmola that is published for oil–water flow which includes wide range of operational conditions including fluid properties, pipe diameters and pipe materials. One of the advantages of the new proposed formula is that it also performs well for super viscosity oils.

Water can contain microorganisms and cause deposition and corrosion in cooling tower systems.Therefore, treatment of thewater of cooling towers is important and essential.Various biocides are used to remove bacteria and disinfect the water of cooling towers,the most commonly used of whichare sodium hypochlorite and chlorine compounds. Two chlorinated water,(hypochlorous acid) and (sodium hypochlorite) were tested in this studyon two pilot and industrial cooling towers.The results of experiments on the pilot tower showed that the performance of hypochlorous acid in disinfection and removal of bacteria and microorganisms has a high capability.The total bacterial count decreased from 10000 (cfu/ml) to less than 800 (cfu/ml) compared to sodium hypochlorite.Experiments and researches were performed on the industrial cooling tower of the Petrochemical Acetic Acid Unit for six months, in which pH, Free Chlorine, TBC and SRB were measured.Very high disinfection power of hypochlorous acid compared to sodium hypochloriteand also low pH of hypochlorous acid compared to sodium hypochlorite led to a significant reduction in the use of chemicals in the cooling tower.The results of Experiments and TBC and SRB tests showed very good performance of using hypochlorous acid

Cobalt-based perovskites containing strontium and copper (La1-xSrxCo1-yCuyO3) were synthesized by the sol-gel method and characterized by XRD, H2-TPR, N2-adsorbtion, XRF and XPS techniques. The XRD results showed that the rhombohedral structure of perovskites was obtained. The activation energy employed to analyze the activities of samples in the combustion of methane was optimized using full factorial design (FD) by considering strontium (x=0, 0.1 and 0.2) and copper (y=0, 0.25 and 0.5) as the input variables. Analysis of Variance (ANOVA) was employed to investigate the obtained data and a p

The study aims to investigate mixed matrix membranes for absorption of CO2in gas-liquid contacting process by AL2O3 nanofluid as liquid absorbent. PVDF/MWCNT hollow fiber mixed matrix membranes were fabricated absorbent and characterized via relevant characterizations. This study showed that the addition of MWCNT to the matrix led macro cavities to be expanded at the cross section of the membrane. According to the results of gas permeation, surface porosity experienced an increasing trend and in contrast surface pore size reduced. By placing the CNTs in porous PVDF, an increase in the surface contact angle and hydrophobicity of the composite membranes was revealed which could be related to the hydrophobic nature of the added nanopaticles as well as increasing the absorbent average surface roughness.

There are various vital reasons for cementing operation, in which fluid migration through cement slurry, as one of the most dangerous and complicated challenges faces drilling industry has been occurred. This phenomenon has become a global problem with its disastrous effects this review paper focused on the gas migration types, factors affecting on each of them and some theoretical and experimental solution. Immediate, short term and long term are the three types of gas migration based on the lifecycle of the well. There are different strategies to prevent gas migration, each type of migration have special strategies. Technical solution development, application of different cement additives in cement slurry and prediction technique for cement quality are number of strategies are developed. Hydrostatic pressure less than pore pressure and the existence of a path to gas migration are two major factors that must be stopped simultaneously to prevent migration. Understanding the mechanisms of cement hydration in early times is necessary to investigate these factors. Cement hydration can lead to swelling and shrinkage at the same time. At the beginning of cementation chemical shrinkage occurs, followed by swelling and autogenously shrinkage, and their intensity depends on the type and amount of the cement additives, the degree of hydration, the water-cement ratio and the fineness of cement. The most important factors that make the annulus pressure less than the pore pressure are: cement placement, Cement hydration in liquid state, and Cement hydration in solid-liquid state.

The haloacetonitriles (HANs) exist in drinking water exclusively as byproducts of disinfection. HANs are found in drinking water more often with higher concentrations. Human exposure occurs through consumption of finished drinking water, oral and dermal contact as well as when showering, swimming and other activities. The purpose of this study was to investigate the novel hybrid adsorption/ PBS membrane filtration process used to remove haloacetonitriles from aqueous solution. The efficiency of the PAC adsorbent was also evaluated at different pH, which confirmed efficacy of PAC at pH of 8.A maximum removal of DOC (98.7%) was obtained with 150 mg/L PAC dosage at a solution pH of 8. HANs sorption process followed the pseudo second order kinetic model and the Langmuir isotherm gave the best correlation of adsorption.

In this study removal of haloacetonitriles from aqueous solution by employing a novel hybrid filtration process is investigated. The application potential of the oxidized multi-walled carbon nanotubes (O-MWCNTs) as adsorbent was investigated by evaluating the effect of different process parameters. Solution pH significantly affected the removal of DCAN (as a model of HANs) due to its strong effect on the charges of the adsorbent and the adsorbate. A maximum DOC removal of 98.7% for was achieved with 150 mg/L oxidized MWCNTs dosage and at a solution pH of 8. Finally, the nanofiltration technique using a PBS membrane was effectively employed to reject the wastewater pollutants (HANs) proprly.

Given that most of the gaseous constituents of industrial chimneys are usually carbon dioxide which is one of the most important greenhouse gases. It seems that the hydration process is one of the newest methods for the separation of this gas from gaseous mixtures. In the gas hydrate formation industry, in addition to disadvantages, there are some advantages such as gas separation, transmission, and storage. Therefore, it is important to determine the appropriate promoter for the formation of gaseous hydrates as well as to find the inhibitor. In this study, the effect of tetra-n-butyl ammonium chloride (TBAC) (which is a thermodynamics promoter) and alkyl poly glucoside (APG) as a nonionic surfactant on the surface tension of carbon dioxide hydrate formation process have been studied. The experiments were carried out in a 218 cm3 batch reactor. The surface tension of CO2 hydrate has been determined at different concentrations and different temperatures and pressures. The nucleation classical theory has been used for this purpose. Designing the experiments performed by Design-Expert software. The results show that increasing the APG and temperature leads to decreasing the surface tension and in contrast, induction time decreases, and the experimental model of the effect of these parameters on surface tension presented as R2 = 0.9898.

Corrosion has been the greatest problem in oil and gas industry, and many experts have always tried to combat this major problem. This has been given to the corrosion and inspection in oil and gas industry. Corrosion in oil and gas wells is driven by some electrochemical mechanisms, and when the system reaches a temperature below the dew point, the moisture will be converted to liquid and many droplets form on the pipe's wall. The corrosion in pipelines' coatings is one of the main problems in oil and gas industries for which a huge amount of money is spent each year. Coating is the first defense line in front of a corrosive environment in which pipes have been buried. Good function of coating depends on its adhesion to the metal surface. Finally, according to our results in this article, we show that, the chemical compounds inside the coating such as chlorides and sulphides can play an electrolyte role, which accelerates corrosion.

Naphtha catalytic reforming is one of the main processes of gasoline production with high octane number. Inactive catalysts and changing the products distribution is an important issue in this process. In this paper we discussed the kinetic overview of catalytic reforming units (fixed and continuous reforming). The catalyst activity model introduced in this research study has been used as a function of temperature and process time to detect the catalyst deactivation. The kinetic model and catalyst activity were estimated by using the genetic algorithm as well as overlapping the proposed model results with the experimental data. The results of the modeling showed that the amount of the aromatics during the reactor reduced the trend due to the decrease in the amount of paraffin and naphthen. After the process modeling, the effect of different factors such as time, reactor temperature changes, reactors operating pressure, and the ratio of hydrogen to hydrocarbon on the activity of catalysts and distribution of the products were investigated. The results revealed that, the aromatics rate decreased and coke formed rate on the catalyst surface increased by catalyst activity passing time. Also, increasing the input temperature and reducing the ratio of hydrogen to hydrocarbon enhanced the aromatics produced rate.

In this study, the processes led to the production of gasoline and reactions resulting in increasing the octane number in the catalytic conversion unit with continuous resuscitation has been described first then simulated with Petrochem software. Considering all the research and investigations, the best recommended values of operational variables for producing high quality gasoline at nominal capacity has been achieved to account for temperature 525 degrees centigrade in the reactors input, flow rate of 22 tons per hour with 93% hydrogen purity, pressure 5.5 relative bar of the circulating gas compressor output, concentration of 0.9 percent weight of catalyst chloride, Naphtha hydrogen purification unit which resulted in the production of 25630 gasoline barrels per day and 0.37 volume percent benzene that the mass efficiency of the catalytic converter.

Natural gas and crude oil in natural underground reservoirs are in contact with water. Stability of these compounds at the presence of both components and complete dependence on the host molecules by forming holes in their guest molecules are replaced. There are many gases such as methane, ethane, propane, carbon dioxide, hydrogen sulphides that can play the role of guest molecules. The natural gas hydrate formation in different sectors of the oil and gas industry in downstream processes causes the production to stop or decrease. Therefore, the need to know the causes and conditions of hydrate formation is strongly felt. In this study, Van der Waals and Platteeuw model was used to predict hydrate formation conditions. The prediction of hydrate formation conditions needs equilibrium fugacity of gaseous components, and for the equilibrium molar component of water.

The aim of this study is to investigate naphtha Gasoline unit catalysts. In two-factor catalysts, platinum or palladium was used as the active metal on the base alumina chloride, zirconia, and zeolite. Considering the fact that refining and gasoline processes are expanding and refineries in Iran are required to produce cleaner fuels that meet environmental standards, investigating different kinds of light naphtha gasoline unit catalysts can greatly help to promote production of clean fuel and make production process more efficient. Light naphtha gasoline is normally conversion of normal pentane and normal hexane compounds to its branched compounds. Also Light naphtha its derivatives and it is done by chlorinated ammonia or zeolite catalysts in one or some fixed bed reactors.  Activity of two-factor catalysts strongly depends on acidic and metal sites. For example, in catalyst Pt./HY, which is a kind of zeolite catalyst for Gasoline Units, the optimal ratio of strong acidic sites to metal sites in n-heptane Gasoline is determined to be less than 6. In this work, various kinds of catalysts used in isomerization unit were identified and considered.

The catalytic conversion of naphtha is a refinery process in which heavy naphtha feeds through the catalytic bed of several reactors at high temperatures and pressures that potentially increase the aromatics content of naphtha and its octane number. Usually, naphtha feed is used to remove the impurities that prevent useful reactions and cause poisoning of reformer catalysts. Operating abutments for the catalytic converter unit are temperature, pressure, metallurgical agent, hydrogen to hydrocarbon ratio, and chlorine ratio. In this study, Operational Conditions in Octanizer and Hydro-treating Units in oil refinery companies is investigated and optimized the conditions of catalysis.

Gas consumption rate is an important factor in the kinetic study of gas hydrate formation. In this study, the kinetic of the hydrate formation was examined in water + carbon dioxide + graphene oxide and water + carbon dioxide + graphene oxide + sodium dodecyl sulfate (SDS) systems. The experiments are carried out at 0.05 and 0.1%of graphene oxide nanoparticle weight and 400 PPM SDS solution at 3.6 MPa and 4 MPa pressures and temperatures of 275.65, 277.65, and 279.65 K. The results show that as the pressure rises, graphene oxide is responsible for the increase in the storage capacity and gas consumption at constant temperature so that using graphene oxide at 0.1% weight increases the storage capacity by 4.2% and molar gas consumption by 3.8% at the pressure of 3.4 MPa compared to the 0.1% weight. When the surfactant, SDS with the concentration of 400 ppm, is used, storage capacity and gas consumption increase by 38% and 26%, respectively.

Amine solvents are extensively used on an industrial scale for removing carbon dioxide (CO2). The presence of some additives in amine solvents has a desirable effect on CO2 absorption kinetics and also improves the absorption process. In this study, graphene oxide (GO) nanoparticles and the anionic surfactant sodium dodecyl sulphate (SDS) were used as additives to the amine solvent. The number of CO2 moles that were used (ng), the values of the diffusion coefficient (DAB), and the mass transfer coefficients of CO2 gas absorption in the amine solvent (Kc) were determined. Furthermore, the effect of the additives on the kinetics of CO2 gas absorption in the amine solvent was investigated. The results showed that mass transfer coefficients increased with a decrease in pressure and an increase in temperature as well as in the SDS and GO concentrations. The values of the mass transfer coefficient under different conditions varied between 0.0311 and 0.0587 cm/s. The molecular diffusion coefficient of CO2 in the amine solvent increased from 0.000025 to 0.000287 cm2/s with decreases in the pressure and with increases in the temperature and increases in concentrations of additives. The laboratory data were statistically analyzed via Design-Expert software using response surface experiment design and a historical method. A mathematical relation was proposed to estimate the mass transfer coefficients. Moreover, a mathematical relation was introduced to predict the molecular diffusion coefficient of CO2 in the amine solvent.

One of the main problems in oil recovery via the gas injection is the formation of hydrates in the lines. In order to prevent the formation of hydrate in these lines, which leads to the blockage and sometimes explosion, at first, the equilibrium formation conditions must be determined and then to prevent its formation by changing the thermodynamic conditions or by adding the inhibitors. In this research, the hydrate formation for a natural gas sample has been studied under the various thermodynamic conditions. For this purpose, a gas sample was taken from the natural gas transmission lines. Then, the conditions for the formation of gas hydrates were determined from the experimental equations. Also, by constructing and launching a laboratory system, the experiments were carried out using the Isochoric method and the hydrate formation conditions were determined. The experiments were done at a temperature range of 264 to 300 K and a pressure range of 5 to 45 bar in the pure water. The results showed that, with increasing temperature, the equilibrium pressure of the hydrate formation increases and with increasing pressure, the equilibrium temperature of hydrate formation is reduced.