Sharif Digital Repository

Highly active unsupported MoO3 and (Co) MoO3 catalysts were synthesized utilizing the solution combustion method where the Ammonium molybdate powder and an organic additive were used as precursors. Different organic materials including Ethylene Diamin Tetra-acetic acid (EDTA), Polyethylene Glycol 200 (PEG 200), Sorbitol and Urea were used as additive in order to investigate the effect of additive structure on morphology and particle size of products. Also various reaction parameters such as the additive/Mo molar ratio, concentration of metal ion in solution, pH of the reaction and temperature of the synthesis media were changed to study effects on product morphology and size. Outcomes were... 

After carbon and hydrogen the most existed element in crude oil is sulfur which is appeared as sulfur compound in fossil fuels. Sulfur might be converted to hydrogen sulfide by hydrodesulphurization operation. The increasing demand for sulfur removal has required large improvements in hydrodesulphurization technology.Most hydrodesulphurization processes use fixed-bed reactors, however, there are still some disadvantages with performing hydrodesulphurization in these reactors. The most important one is high exothermic nature of hydrodesulphurization process which cause some problems for catalyst in these reactors and decrease the performance of catalyst. In order to solve the temperature... 

Monolithic nanocatalysts for naphta hydrodesulfurization process have been prepared and evaluated. Commercial cordierite monolith was used as a ceramic substrate. Initially, the monoliths were pretreated with nitric acid solution in order to increase specific surface area. After that, carbon nanotubes were grown through catalytic decomposition of methane over prepared monoliths. Finally, the CNT-coated monoliths were oxidized with ozone and an aqueous solution of H2O2. For the preparation of HDS Co-Mo nanocatalysts, the metal content of aqueous solution including cobalt nitrate, ammonium heptamolybdate were then impregnated onto the prepared supports. Next, samples of prepared supports and... 

The sulfur compounds in crude oil cause air pollution, metallic equipments’ corrosion and refinery catalysts poisoning like reforming catalysts. Therefore it is necessary to use hydrodesulfurization catalysts for sulfur content reduction. Hydrodesulfurization is the most common desulfurization method in the industry. In this method, sulfur compounds react with the hydrogen in presence of ComMo/γ Al2O3 catalyst and under hard operational conditions like high temperature ( 300-340 ͦC) and high pressure (20-100 atm of hydrogen). Then,these compounds are turned into hydrogen sulfide and hydrocarbons. In the next step, produced hydrogen sulfide will be eliminated from oil cutting.In this... 

Sulfur compounds are very undesirable and result in Corrosion in metal equipment, air pollutions and poisoning of refinery Catalysts such as reforming Catalyst. Therefore, application of Hydrodesulfurization (HDS) process in order to decrease the amount of sulfur in petroleum cuts has a great importance. HDS process is the most usual and efficientmethod for sulfur removal. In this method sulfur compounds at vigorous operating conditions such as high temperature and pressure in the presence of catalyst react with hydrogen and produce hydrogen disulfide and hydrocarbon. Sulfided Co–Mo catalysts are widely used in this process.
The aim of this study is to prepare and improve CoMo/γ-Al2O3... 

One of the most important world issues is environmental constraints regarding the pollutants released by transportation fuels and refinery products, sulfur reduction being one of the most significant objectives. Deep hydrodesulfurization processes result in great sulfur reduction in refinery streams. However, such harsh process conditions increase undesired side reactions and facilitate coke formation as well as affecting the surfaces. More effective alternatives for hard process conditions are highly active and selective hydrodesulfurization catalysts, which enable the process to be performed at milder pressure and reaction conditions. Catalyst bases play a very important role in hydrogen... 

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... 

Environmental destructive effects of gases caused by combustion of sulfur compounds in the fuel, poisoning of catalysts, corrosion of equipment, as well as intensification of environmental considerations and new standards adopted for maximum sulfur content has made the desulfurization of fuels important; The desulfurization method using hydrogen has a high potential to remove sulfur. One of the major challenges in this process is to find the proper catalyst that has the best performance for this process. Ni (or Co) Mo (or W)/ γ-Al2O3 catalysts have high potential for using as a catalyst for the desulfurization process from a variety of large-scale or industrial hydrocarbon cuts. According to... 

The harmful environmental effects of gases resulting from the combustion of sulfur compounds in fuel, poisoning of catalysts, corrosion of equipment, as well as the intensification of environmental considerations and new standards adopted for the maximum amount of sulfur, have made the desulfurization of fuels important; Meanwhile, the desulfurization method using hydrogen has a high potential to remove sulfur compounds. For example, diesel fuel contains a variety of impurities such as sulfur, nitrogen (basic and Non-basic), and aromatic compounds, the sulfur in diesel fuel causes many problems related to environmental pollution and corrosion of engine components. Also, due to the high...