Sharif Digital Repository

The aim of this project is Industrial Solvents (White Spirit) producing in Tehran Refinery. For this manner “Wild Naphtha” from Gasoil Hydrotreater and Kerosene Hydrotreater Units was chosen as feed stock for solvents preparation. In addition, Pentane Recovery Column is selected for Simulation and Optimization based on Wild Naphtha. As a Result, Abadan White Spirit 402 and 410 has been produced and a side stream which is full of Aromatic is obtained. Simultaneously, Tray Hydraulics and Solvents production in different cases (Various Pressure and different Split Ratio of Feed Stock) are evaluated, so optimum Tower process conditions such as pressure, Temperature and Split Ratio of Feed Stock... 

In this thesis heat transfer coefficient and temperature distribution of two Non-Newtonian and a Newtonian fluids in stirred vessel are investigated using Computational Fluid Dynamic (CFD). This vessel is agitated with new impeller called MAXBLEND. Non-Newtonian fluids are aqueous solutions of carboxymethyl cellulose 1.5%w/w and xanthan gum 3% w/w and Newtonian fluid is glycerin. This vessel is simulated in laminar regime with Reynolds number less than 14. The results of simulation are compared with correlation proposed by Kawase et al. Furthermore as a new research for this impeller, the effects of vessel diameter and position of impeller in the vessel on heat transfer coefficient are... 

Pipeline transfer is the most commonly method for natural gas transportation. Potential force of natural gas transportation in pipeline is pressure difference that is generated in Gas Compressor Stations (GCS). For each 100 to 150 km of pipeline, one GCS is required that pressure is increased usually from 700 to 1000 psig. Each station contains different process equipments such as turbines, compressors, scrubbers, filters, air coolers, throttling valves and pipes with instruments. It is shown that about 10 percent of the generated pressure difference, decays in GCS.
In this thesis, pressure losses are studied and initiatives are purposed to reduce them in a Gas Compressor Station. Then... 

Brine in crude oil causes many problems that underpin the importance of its separation. In recent years brine in crude oil has been increased with increase of the oil fields lifetime and its separation has been more important. One of the most effective separation methods is electrocoalescence. In this research, the simulation of brine droplets motion and their coalescence under the effect of electric field have been investigated by using the Computational Fluid Dynamics method and the droplets size distribution has been calculated under different values of electric field magnitude. The motion of two single brine droplets in stagnant oil phase and the behavior of many numbers of droplets in... 

The present thesis has provided more fundamental understanding of granulation rate processes (such as coalescence, attrition and breakage) by investigating the effects of operating parameters on product properties. The studied process was wet granulation carried out in two high shear mixer granulators. Granulation duration, binder mass and impeller speed were considered as operating parameters and granule size distribution (measured by sieving) and granule binder distribution (measured by thermogravimetery method) were regarded as product properties. Experiments were conducted in two analogous cylindrical and conical high shear granulators. The obtained experimental and theoretical results... 

In the present work, the possibility of using a cross flow microchannel heat exchanger in cryogenic service for natural gas liquefaction has been numerically investigated using 3D computational fluid dynamics approach. Microchannels of rectangular and triangular cross section with a hydraulic diameter of 0.667 and 0.472 mm respectively have been constructed in Gambit and Fluent is used as the solver of numerical simulations.For solver’s equations validation, the existing experimental data on flow of water through rectangular microchannels has been modeled by CFD. Comparison of CFD results with experimental data shows a good agreement.Both models are constructed of three distinct layers. In... 

Catalytic Reforming is a chemical process to convert naphtha feed stock into aromatic hydrocarbons and high-octane products. This process firstly was used in 1940s and since then has been considering as one the main units in oil refineries. It involves several complicated reactions which occur at high temperature and pressure in three or four series of reactors. There are various technologies for regeneration of the catalysts. The latest technology for this process is continuous catalytic regeneration.
The aim of this study was to optimize the catalytic reforming process by minimizing the deposited coke on catalyst surface and maximizing the octane number. To reach this aim, the... 

The main purpose of this project is to achieve better design by using exergy analysis. First steam methane reforming process of Tehran refinery is simulated using ASPEN HYSYS. Reformer and high temperature and low temperature shift reactors are simulated using trusted kinetics from literatures and results are compared with plant data and، and there was a good agreement between simulation and plant data. A MATLAB program is written to calculate stream exergies and equipment exergy destruction using AUTOMATION. Streamlined life cycle assessment is done using sustainably metrics، and environmental impacts are evaluated. The main environmental impact was global warming. After exergy destruction... 

The huge jam complex unit in assaluye (tenth olefin plan) with the capacity of 1320000 tons of ethylene and 306 thousand tons of propylene is considered as one of the biggest olefin units of all world. It is found that the bottleneck of increasing the capacity is the demethanizer unit. In this thesis, after simulation of the demethanizer towers, capacity enhancement is accomplished along with comparing the outlet stream with PFD data in terms of mass fractions, temperature and pressure. in addition, the hydrolic treat ment of towers is checked. This is continued till a problem occures in each of towers. In the bottleneck capacity , a solution and some changes have been offered. Thereafter... 

With the huge natural gas reservoir in Iran, LNG production processes have a great attraction for the gas industry. The main goal of this project is the design of a skid mounted of a small scale LNG unit. A pretreatment unit was designed which includes two adsorption towers. In these towers, the type 13X adsorbent, eliminate traces of CO, N2 and H2S. For the cryogenic side a N2 expansion cycle was considered, after studying different cycles. It is found that N2 expansion cycle is one of the best methods for mini LNG production unit. In this process N2 gas was compressed to 35 bar in two stages and after precooling, enters to an expander to produce the -165 C cold in a cold box. The natural... 

This thesis tries to suggest a simple solution to reduce the amplitude of occurred fluctuations in mixing tees. Temperature fluctuations can induce cyclical thermal stress and thermal fatigue. In order to estimate the lifetime of pipeline material and reduce the frequency and amplitude of these fluctuations, an accurate diagnosis of these fluctuations must be conducted. For this aim, a comparison between Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) models was carried out to show the ability of LES model in prediction of temperature fluctuations. The effect of Peclet number on the amplitude was discussed. The effect of placing simple pipe segments and orifices to... 

The aim of this study is to survey the ability of vortex tube cascade for separating heavy components of a gas mixture. For this purpose, three vortex tubes based on previous experiences have been manufactured. Also, a helical double pipe heat exchanger has been designed and constructed. Because of the vortex tube’s ability in developing thermal separation, the effect of thermophysical parameters like feed’s temperature, inlet and outlet pressure of air on the thermal separation performance were evaluated. The recommended correlations for estimating outlet temperature of hot and cold flows, have been validated against experimental data. Moreover, various arrangements of vortex tubes to... 

Supersonic separation is a modern technology which is used in petroleum’s industry. Supersonic flow is obtained by converging-diverging nozzle in which by decreasing pressure and increasing fluid’s velocity, we can reach low temperature which is required for separation. After separation in low temperature, pressure is recovered via normal shockwave or a second nozzle. In the case of using second nozzle, fluid’s velocity is decreased and its pressure is increased. In these separators, we have two important issues: Separation efficiency and Pressure recovery . On the other hand, nozzle’s performance depends on two sets of factors: Factors related to nozzle’s geometry and Factors related to... 

One of the most undesirable compounds present in various crude oil cuts are sulfur compounds That creates a lot of problems in different stages of refining and when consumed. In this study, the hydro-desulfurization process that is the most common method of treating oil cuts in the refinery industry and in terms of economic and environmental special place in the oil industry and related industries, has been discussed. In hydro-desulfurization process, sulfur compounds under high pressure and temperature, are converted to hydrogen disulfide in a catalytic reactor. In this study, the catalytic reactor may be simulated with the utmost care. In this context, Euler-Euler two-phase model that is... 

To investigate the metallic cation (Ni and Pb) removal performance of the rice barn-obtained biochar which was modified by nitric acid and titanium nanoparticles (TiO2) adsorption tests were conducted in continuous and non-continuous systems. First section addressed the characterization of the synthesized sorbents using field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X ray spectroscopy (EDX) and sorption-desorption porosity analysis (BET). In the second section, the effect of different parameters such as pH, initial concentration of the metallic ions, temperature, time, sorbent content, ionic... 

Supersonic separators (3Ss) are used in gas separation processes such as dehumidification of humid air thanks to their high performance and good pressure recovery. Moreover, 3Ss because of their simple mechanical construction and absence of any environmental impact are preferred to other dehydration methods of natural gas, such as adsorption, cooling, and membrane. Also using the 3Ss for relatively large facilities with considerable investment is more than evident. In the first phase of present study, 2-D simulation is performed to investigate the effect of operational and thermo-physical parameters on shockwave position in a specially conceived wet air 3S. Moreover, the effect of cyclonic... 

Compressor stations with gas turbine drive have become common in transport of natural gas. However, the thermal efficiency of the gas turbines used in these stations is low. One reason for this is that 70% of the heat of combustion of the fuel gas used by the gas turbine is lost with its exhaust gases. Hence, heat recovery from gas turbine exhaust gas would increase the cycle efficiency by decreasing the fuel gas consumed. On the other hand, gas turbine efficiency highly depends on the climatic conditions of operation. Among several well known methods of performance improvement, the use of an absorption chiller for inlet air cooling has been studied from both process and economic points of... 

In order to prevent the CCR catalysts from sintering and maintaining their acidity, some chloride compounds are added to these catalysts during regeneration process. The existence of these compounds in downstreams units and equipment causes problems such as corrosion, fouling, etc. Therefor for eliminating these chloride compounds from the exit stream a chloride adsorbent is used. The common compound that is suggested for this application is activated alumina for its high surface area. When Olefin or Aromatics exist in the stream, that is common in many units, a side reaction happens and green oil is formed. In this study, different factors in green oil formation has been studied. Although... 

The delayed coking process is one of the common thermal process technique that used to improve the quality of heavy oil. In this process, heavy feeds such as vacuum residues have been heated in the furnace to temperatures up to the 480-500 °C. For the cracking reactions the heated feed have been sent to the drum that is placed after the furnace. Since the reactions begin inside the furnace and coke is one of the products, deposited on the wall of the tube. With the deposition of coke on the tube wall and the reduction of heat transfer, the temperature of the tube have been increased with the increasing of the flame temperature to save constant heat flux. Therefore, the study of thermal... 

Sea water desalination needs fossil fuel and electricity. Although there has been major technical development in this case , including RO technical improvements, mainly motivated by oil exporting rich countries, under developed region still need investments for these processes. In this MSc project , a process using renewable energies is investigated to minimize operating costs. “Green technologies” for water desalination will become attractive with oil price increase. The green desalination process is simulated and sensitivity analysis of parameters is investigated. Based on the results, the optimum number of effect is 6, last effect pressure equal to 0.64 bar, and the sea water flow rate to...