دکتر محمد تقی صادقی

With the increase of offshore drilling for oil extraction, exploitation and transportation of oil and oil products, on one hand, the risk of oil spills and oily waste water in the marine environment has increased significantly, on the other side, easy, controllable and economical modern methods for oil-water separation has become necessary. Oil spills and oily waste water have a disastrous effect on the ecosystem and environment, and the separation of crude oil associate water by traditional methods also requires the use of expensive chemicals. During the past few years, the development of special wetting materials for the separation of water - hydrocarbons has attracted much attention from researchers, and many researchers have created materials with selective wettability that are hydrophobic/oleophilic or hydrophilic/oleophobic, which can be used to separate a selective phase from an oil (hydrocarbons, petroleum, fats)-water mixture. In the current research, the possibility of using nonostructure tungsten oxide as a coating on stainless steel mesh is investigated in order to check the possibility of changing the wettability of the mesh and using it to selectively separate one of the water or hydrocarbon phases from their mixture. For this purpose, both sides of the 5 micron stainless steel mesh were coated with nanostructured tungsten oxide by hydrothermal method. The measurement of the contact angle of water and oil on this mesh showed that the wet coated mesh is hydrophilic in air and becomes oil-repellent when submerged. Due to such wetting behavior, this mesh can be used to separate oil and water mixtures. A piece of stainless steel mesh was placed in an autoclave with an inner Teflon coating containing 250 mL of an aqueous solution of hydrated sodium tungstate, hydrochloric acid, and oxalic acid. The autoclave was placed in an oven at 180°C for 3 hours. After cooling to room temperature, washing with ethanol and Water and drying, it was roasted in an electrical furnace of 350°C for about an hour. The wettability of the hydrophilic and underwater oleophobic filter was also evaluated by measuring the static contact angle. The wetting behavior mechanism of the constructed filter is mainly related to the hierarchical structure of the nano-spherical coating of the surface and its relative roughness, and hence the hydrophilicity of the surface increased. The EDS analysis of the coating formed on the mesh and the FE-SEM and TEM images of the fabricated filter all indicate the formation of WO3 nanostructured coating on both sides of the stainless steel mesh.

CO2 injection processes are among the effective methods for enhanced oil recovery. A key parameter in the design of CO2 injection project is the minimum miscibility pressure (MMP). From an experimental point of view, slim tube displacements test routinely determines the MMP. Because such experiments are very expensive and time-consuming, searching for fast and robust methods for determination of MMP is usually requested. The Neural Network (NN) and Support Vector Machine Regression (SVM) were used to designs networks for estimation MMP. The Networks Trained by trusted data including independent variables. The validity of these new models were successfully approved by comparing the models results to the pure and impure experimental slim-tube CO2-oil MMP and the calculated results for the common pure and impure CO2-oil MMP correlations. The average accuracy of the predicted values for the neural network in terms of coefficient of determination (R2) and mean square error (MSE) are 0.9863 and 0.0018. These values for the SVM regression are 0.9870 and 0.0017, respectively. In addition, the new models could be used for predicting the impure CO2-oil MMP at higher fractions of non-CO2 components (Up to 100% for methane and 50% for hydrogen sulfide).

In this study, gas phase holdup in a gas-liquid bubble column reactor was experimentally studied. To conduct experiments, a bubble column with a height of 54 cm and a diameter of 10.4 cm was applied. The studied systems include water-air, Gasoline-air, and Behran oil-air. Experiments were carried out in the range of 400-50 rpm agitator. Based on the Buckingham π theorem, a semi-experimental model for gas phase holdup was presented. The results showed that with increasing viscosity from 0.001 to 0.0136 gas phase holdup loss due to high adhesion of bubbles at high viscosity and also the increase of bubble size at the output from the distributor decreases from 0.41 to 0.333. Among the selected systems, the gas phase holdup of the gas-air system was maximized. The results also showed that in materials with low viscosity, the gas phase reduction was due to the formation of liquid vortex movement and air canalization by the agitator. The best agitator speed to increase the gas phase holdup at water and oil are 150 and 400 rpm, respectively.

Reservoir oil recovery and efficiency of EOR projects include designed water injection influenced by factors such as oil composition, porosity, permeability, rock mineral composition, porous space distribution, and pore size. The injection of designed water into the carbonate reservoir has always faced many ambiguities. This category of ambiguities has been further investigated and analyzed in this study by examining one of the influential factors, such as polar compounds of oil and its Physico-chemical interactions during the production process. Polar components in crude oil affect the electrostatic interactions at the mineral surfaces, affecting the wettability conditions. This study performed experiments measuring contact angle and spontaneous vascular process on limestone samples. For this purpose, cores with the same conditions are saturated in different oils regarding the percentage of polar compounds. Moreover, they are adjacent to specific components of active ions in designed water. In this regard, using the collected results, we can interpret and study how to participate in the reaction and the effectiveness of polar compounds in the oil. The results show that the amount of oil production due to water injection depends on the chemical composition of the oil and the interaction between water and oil, and in addition to the amount of asphaltene in the oil, it is also affected by the amount of organic carboxylic acids in crude oil.

The process of injecting smart water into carbonate reservoirs has always faced many challenges. In this study, by examining one of the effective factors such as ionic compounds active in smart water, these ambiguities have been further investigated and analyzed. The reaction between three phases, oil, rock and saline, which leads to a change in wettability, requires the presence of ionic compounds active in smart water and active compounds in oil. The presence of these compounds in the desired concentrations is the driving force required to perform ion exchange reactions followed by a change in wettability. In fact, the optimal concentration of active ions leads to the formation of a stable water film and a change in the wettability of the rock. In this study, experiments measuring the contact angle and the spontaneous imbibition deferens process were performed on samples of limestone.  For this purpose, the cores with the same conditions are located in the vicinity of different compounds of active ions in smart water. In this regard, using the collected results, it is possible to interpret and study how to participate in the reaction and the effectiveness of the active compounds of smart water. It can also be concluded that cations in the presence of sulfate ions can have a positive performance at the minimum concentration in seawater and have acceptable efficiencies of about 41% in experimental conditions.

Optimal reservoir management, modeling and production, depend on understanding the connectivity between production wells in an oil reservoir. Using numerical simulation and a reservoir permeability map can clear this feature, however, it is a time-consuming method and the presence of uncertainty in the input data of simulators leads to employ other methods to understand the feature. Having new sensors that are permanently placed in the wellbore, large amounts of production data (production rate and bottom hole pressure) are available. In recent years, intelligent data-driven techniques have been used to work with the large amount of data obtained from production wells. This paper uses a data-driven approach based on detecting important production well events during its production life. Important well events are divided into three categories: (1) increasing, (2) decreasing, and (3) no flow (shut in the well by operator). These events are identified using derivative and slope of the production figures and some limiting factors. Afterwards, the algorithm has to find the related events between the production wells, and based on the importance of the events, the inter-well connectivity among production wells is determined which it is shown as a connectivity map. A synthetic reservoir was first developed in the Eclipse simulation software, and the three high-permeability streaks were considered between three well pairs. Next, its production data were used as the data-driven model’s input, which it is programmed in MATLAB software, in order to identify the three high-permeability streaks via the data-driven model.

In this research, carbon dioxide absorption by 13x zeolite was studied in a fixed bed reactor. The adsorption experiments were carried out in a fixed bed with 1 m height and 10 cm diameter. The adsorption experiments were carried out to investigate adsorption operating parameters including temprature, pressure, gas flow rate and adsorbent amount. The analyses result showed that adsorbent diameter avarege is 1.92 nm and interface area is 697 m2/gr. The experimental result showed that adsorption rate of carbon dioxide was increased by increasing pressure and bed height and decreasing temperature. The evaltuation of adsorption isotherm data showed that the CO2 adsorption is physical and the adsorbent has high capacity. Also the isotherm data was evaluated with different isotherm models and the results showed that Frendlich model with correlation coeffient 0.999 has good agreement with experimental data.

A method for transferring heavy oil emulsion with high viscosity heavy crude oil through the pipeline. Despite the substantial reduction in pressure and viscosity of the emulsion water/ oil, water must be removed before entering the refining process. Several methods have been proposed for the separation of water from the emulsion. The most common method demulsification oil is heating the emulsion. In addition, other methods have been introduced for deemulsification, despite the benefits, limitations, and problems such as low efficiency, high equipment costs and environmental problems are substantial. Therefore, due to the problems mentioned research has been directed toward new technologies. Among the methods of the past decade, most attention has been the use of microwave energy for heating instead of conventional demulsification. The advantage of this method is selected and volumetric heating, which causes the aqueous phase is further influenced by the type of heating and water separation efficiency increases. The microwave will cause the rotation of water molecules thereby neutralizing zeta potential leads to the breakdown of hydrogen bonds between water and the surfactant.

In recent years, the Fischer-Tropsch synthesis has been considered as an important chemical process for natural gas conversion to liquid fuels. The abundant availability of natural gas and the increasing demand for different hydrocarbon products such as olefins, diesel, and waxes have led to a high level of interest to further develop this process. In this study, a multicomponent reaction engineering model for a slurry bubble column reactor on a commercial scale is developed in order to study the effects of different parameters on product distribution. The modeling results show that different parameters such as temperature, operating pressure, catalyst holdup, and superficial gas velocity affect the syngas conversion and carbon product distribution. In order to maximize the rato of different hydrocarbons products to all the products, the optimization of the operating parameters has been carried out using several optimization techniques such as genetic algorithm (GA), simulated annealing (SA), and gradient method. According to the optimization results, a high H2/CO ratio and low catalyst holdup are required to maximize naphtha, diesel, and wax products relative to the other products. On the other hand, a low H2/CO ratio and high catalyst holdup are required to maximize the olefin products relative to the other products. Moreover, high pressure has a positive impact on the all the products.

One of the best non-intrusive methods for concentration measurement in fluid flow is Laser Induced Fluorescence (LIF). In this technique, a laser used to excite the fluorescent component. Usually, fluorescent dyes such as Rhodamine B and fluoerscein are used as flow tracers. These tracers absorb the laser's energy and then emit a portion of the absorbed energy at the different wavelength. The emitted energy, after passing an optic filter reaches to a CCD sensor which could be quantified for dye concentration measurement. Additionally, this technique is used to whole field temperature measurement. In this article, the fluorescence phenomena, equipments for LIF system, basic theory and some literatures about concentration measurement in fluids have been reviewed.

Track stabilization is an indispensable issue in railway track construction within the initial months of track operation. Construction of rail track on soft and compressible formation soils causes pore water pressure to prolong the consolidation time. The passage of heavy haul trains with considerable imposed trainloads over such deposits causes excessive track settlements and significant reduction in the load bearing capacity of the track. It causes deferment in track stabilization. These deformations lead to less safety and stability of railway track systems. As a result, track maintenance will become a challenging concern. This paper presents a proper model of prefabricated vertical drains to be installed in heavy hauls. This model facilitates achieving to a proper degree of consolidation in an optimum time. In this regard, a finite element analysis was carried out to analyze substructure and superstructure of railway heavy hauls. Parameters including subgrade total consolidation time, subgrade degree of consolidation and track’s total settlement have been derived. Consolidation time for subgarde with prefabricated vertical drains has been also established. The number and distance of the prefabricated vertical drains per unit length have been determined. Furthermore, the optimum length of each drain has been identified taking advantage of sensitivity analysis on stabilized track subgrades with different lengths. Finally, a model,including the number, the distance and the length of drains has been proposed in order to install in heavy hauls.

Environmental pollution caused by noise is one of the most adverse consequences of railways operation. In spite of the vast amount of studies on railway noise, little attention has been paid to the effect of rail corrugation on rolling noise. Corrugation on the wheel tread and the railhead causes vibrations within the vehicle and the track, causing different ranges of noise. There is a need for a thorough investigation into rail corrugation effect on rolling noise. Inresponse to this need, present research concentrates on rolling noise and investigates rail corrugation effects on rolling noise. For this purpose, a thorough field investigation into the noise and corrugation measurements was carried out in this research. Measurements of the noises generated in the track by the passage of railway vehicles in a tangent track and a curve with small radius, were recorded by field tests. Rail corrugation measurement was performed in an indirect method by EM50 track recording car. Results obtained from the field tests were analyzed leading to new findings in rail corrugation effect on rolling noise. The effects of rail corrugation types on rolling noise were indicated. According to the research findings, the formation and occurrence of rail corrugation in curves is much more than that in tangent tracks. Rolling noise is so sensitive to the short-pitch rail corrugation in the tangent track. Moreover, it was noticed that the short-pitch rail corrugation in the tangent track is the most controlling factor because of having higher rate of rolling noise in the test site which leads to dissatisfaction of train passengers and residents of nearby residential areas. However, the lowest effect of rolling contact fatigue corrugation on rolling noise was observed for the curve.

The accuracy of the measured data is very important for better quality prediction by soft sensors. In order to determine the quality of the treated gas oil، a soft sensor is designed. The soft sensor design is based on a new machine learning technique called support vector regression (SVR). An integrated technique was developed for data preprocessing. In this technique، wavelet analysis and vector quantization were being used sequentially for random error elimination، data compression، and unusual data omitting. Different methods of wavelet analysis were used to remove the random errors and the best method was selected. Random errors were deleted using Harr and Daubechies basis function where Rigrsure، Minimaxi، Heursure، and Sqtwolog were the threshold algorithms. The results showed that the db4 basis function with Rigrsure threshold algorithms provided the best results for error removal. AARE and RMSE for this method was better than the other types of wavelet functions. Additionally، the results of SVR training based on the pilot plant data showed AARE of 0. 053. This showed the high accuracy of the SVR model for predicting treated gas oil quality.

In this paper, a turbulent lifted diffusion jet flame is studied using the composition probability density function approach in a two-domensional domain with detailed chemistry. The main purpose is to investigate the effect of density variations on scalar fields and lift-off height. For this purpose, the standard k- model as well as a modified turbulence model for variable density conditions are employed to investigate the impact of turbulence models on the flame behavior and the place of stabilization. The results show that the best agreement between the numerical results and measurements is achieved using the modified turbulence model. A comparison between the numerical results and measurements shows that the standard k- model over-predicts the spreading and decay rates in the jet. Using the velocity-pressure gradient term in the modified turbulence model resolves the relevant problem to a great extent and leads to better results than those of the standard k- model.

Hydrogen storage in large quantities is a main factor to produce ‘‘Hydrogen Economy’’. Recently, with the development of the hydrogen economy and fuel cell vehicles, the manner of storing and delivering large quantities of hydrogen arises as a major problem. Nowadays several hydrogen storage methods are available. Technologies are being developed and/or engineered other than the classical compression and liquefaction of hydrogen, which are based on the chemical (e.g., ammonia) and physical (e.g., carbon nanotubes) adsorption of H2. Also, a novel technology is in progress, which is based on clathrate hydrates of hydrogen. In this article has been tried to discuss at length the possibility of hydrogen storage in hydrate and thermodynamic models.

Development of an optimized strategy for the maintenance of Iranian railway track maintenance in a form of management system was made in this research. Through reviewing the current maintenance management system in the USA, Europe and Asia as well as investigating the characteristics of railway structure and current maintenance approaches in Iran, a new algorithm was made in order to improve efficiency of maintenance decision system and maintenance planning in Iranian railway industry. The practicability and reliability of the new maintenance algorithm (model) were evaluated by applying the new proposed algorithm in a railway line in Tehran province. It was shown that the new proposed maintenance management system (algorithm) is effective in providing an optimized maintenance strategies and plans. It was also shown that track operation can be evaluated by sensitivity analyses of the proposed model.

Construction of high speed railways is booming in the world. One of the main issues related to high speed railway is the non-uniform deflection of the rail along the track due to increases in train speed. This study focuses on investigations of the influences of strain speeds on track defections. For this propose, a model of railway track was developed. This model was then calibrated using field results available in the literature. The results of model calibration indicate that the consideration of the track support system nonlinearity has substantially effects on the theoretical results, concluding that the incorporation of the support system nonlinearity is a need in track modeling. From sensitivity analyses of the calibrated model, the effects of increases in train speeds on track deflections were investigated. It is shown that track deflections increase as the train speed increases up to the speed of 140 km/h. However, after this speed, the deflections of the track slightly reduce. It indicates that the critical speed of the track from the deflection point of view is 140 km/h. Research findings here indicate the necessity of further consideration of the critical speed in the design of high speed tracks.

Continuous gas lift process is used to boost oil production in many mature reservoirs، which can no longer produce under natural drive. In this article، application of mechanistic flow maps as well as the correlations estimating pressure drop in a gas lifted well، as the most complex and time consuming part of the gas lift modeling is examined. Using the black-oil model to compute the two-phase pressure drop in a gas lifted well leads to a substantial error due to the changes in composition and bubble point pressure along the well. In order to describe the thermodynamic behavior of the hydrocarbon fluid، a multi-component compositional description has been applied using the reduced parameter method. The results show that the empirical maps and correlations lead to severe discontinuities at transition points between the different flow regimes. This causes an unacceptable error when computing the pressure drop.

The effects of meshing type and turbulency model on distribution and volume fraction of the liquid phase on the MontzpakB1-250Y structured packing at steady state condition was investigated employing computational fluid dynamics (CFD) technique. The volume of fluid method was used to simulate the liquid distribution, while different meshing types (e.g. tetrahedron and cooper algorithm) and turbulency models (including Standard, RNG and Realizable) were used for modelling the system. Resulted equations were numerically solved employing the finite volume method. Liquid maldistribution was studied using parameter and volume fraction of the liquid phase at various velocities and conditions. The results were compared with experimental data reported in the literature indicating that a proper selection of meshing type and turbulency model can significantly affect hydrodynamics simulation of the structured packing.

Rotary cement kiln as heart of a cement production plant plays an important role in overall energy consumption and product yield. Therefore, the process behavior and physical parameters affecting the final production need to be investigated. Modeling and simulation of the rotary cement kiln have been done by several researchers considering dynamic and steady state behavior of the process. In this research, different models presented by other researchers were evaluated and their advantages and disadvantages were studied. Next, a general and comprehensive model was developed with the aim of optimization of the process. Due to the complexity of the Differential and Algebraic Equations (DAE’s) constructing the model, a powerful method should be employed in order to solve the complex system. Simulation results were compared to the result from a case study presented in the literature. Moreover, Genetic Algorithms (GA) was used as a strong tool to find optimum parameters and operating conditions for production of different cement types. Having maximum production as objective function, different values for the parameters and conditions were resulted from the numerical optimization of the process. It was found that for some fixed plant geometries, different optimum values exist for production of a specified cement type.

Na2WO4-Mn/SiO2 catalysts were prepared for oxidative coupling of methane using co-precipitation, wetness impregnation and wet impregnation methods. Catalytic performances of the prepared catalyst samples were examined under the same conditions in a fixed bed microreactor. It was found that the Na2WO4-Mn/SiO2 catalystsprepared by the wet and wetness impregnation methods have similar performances and both methods have superior performances over that of the co-precipitation method. The results also show that the catalysts prepared by the wetness and wet impregnation methods present excellent stability performance. The catalysts were characterized by means of BET, SEM and XRD tests. The results show that the Na2WO4 phase is necessaryfor achievement of the desired performance.

In this study simulation and optimization of an industrial acetylene hydrogenation reactor was studied. Three well known kinetic models were used for a nearly similar catalyst to predict the industrial data. Due to the complexity of the reactions, none of the offered kinetic models could be considered as an exact kinetic model and it is necessary to determine the kinetic parameters. One of the best methods to determine the kinetic of a process is to simulate the process and then minimize the deviations between industrial data and calculated ones. Thus the hydrogenation reactor was simulated at the industrial operating conditions which were taken from an operational petrochemical plant and the optimum kinetic parameters were determined using optimization technique. Since such problem has many local optima, the genetic algorithm (GA) and simulated annealing (SA) methods were used to optimize the kinetic parameters of the three models. Due to the strong dependency of the GA performance on the GA condition, it was tried to investigate the effect of GA parameters on overall GA performance in detail. For this purpose, different GA parameters were used to solve the problem and results were discussed.