Sulfur containing compounds of oil cuts cause air pollution, corrosion of metallic equipments and refinery catalysts poisoning, so using HYDRODESULFURIZATION (HDS) catalysts and reducing sulfur content of oil cuts is critical. These catalysts generally contain a uniform monolayer dispersion of VIB group metal oxides such as molybdenum oxide and VIII group metal oxides such as cobalt oxide on a carrier preferably g-alumina. In this work successive dry impregnation of g-alumina by ammonium heptamolybdate and cobalt nitrate solutions was used to prepare HDS catalyst samples and then effect of impregnation solution pH. Mo and Co solution concentration, drying rate and feed flow rate on the HYDRODESULFURIZATION performance was investigated. The samples were evaluated via scanning electron microscopy, porosimetery and reactor tests. The catalyst sample JDS-C5 shows the ability of reducing sulfur content of the feed from 1200 ppm to less than 1 ppm in the refinery HDS unit operation conditions (T=290 °C and P=15 bar).

Highly active unsupported MoO3 and Co - MoO3 catalysts were prepared by a simple solution reaction method in the presence of different organic additives. Catalysts were characterized by the XRD, BET surface area measurement, SEM and TEM techniques. Results suggested that utilizing different additives produced different morphologies of MoO3 microstructures. Optimizing reaction conditions was found to produce more active molybdenum oxide nanoparticles when urea and PEG200 additives were utilized. XRD and TEM results indicated crystal growth restriction after cobalt incorporation. Catalytic activities of prepared materials were evaluated in the HYDRODESULFURIZATION reaction of Naphtha. Products were analyzed by XRF to determine the residual sulfur content of the feed after the reaction occurred.It was concluded that nanostructures and promoted catalysts had higher activities than microstructure samples. Ultimately, the reaction over the urea-prepared promoted catalyst decreased the sulfur content of the feed of Naphtha from 2420 to 24 ppm, which is considerably lower than that of commercial catalysts.

The purpose of this study is evaluation of complicated kinetic models by means of Genetic Algorithm. Because of importance of sulfur removal from oil products to control environmental pollution as well as preparation of low/ free sulfur feed for reforming process, hydrotreating of oil cuts is one of the most important reactions in refining processes. Rigorous HDS reaction kinetics is nonlinear models which are carried out on bi-functional catalysts. Two parallel reactions; Hydrogenolysis and Hydrogenation, are the major reactions which are carried out on the surface of non-homogeneous catalysts as Ni-Mo/g-Al2O3. In this study, appropriate models of Langmuir-Hinshelwood type kinetics for Hydrogenolysis and Hydrogenation were investigated. The experimental rate data at high constant pressure in different temperatures with different concentrations of dibenzothiophene (heavy sulfur compound), hydrogen and hydrogen sulfide were used for each model. By implementation of GA the best model and Arrhenius parameters were obtained, directly.In this study, a comparison with Levenburg-Marquardt Algorithm has been investigated. It is concluded that LMA is sensitive to the first guesses and there is possibility to trap in local optimum in contrast GA. In conclusion, GA can be used to modeling of rigorous and nonlinear kinetics, without consuming time for writing partial differentiation as we have to do in LMA, and GA is a convergent method to global optimua if we use a reasonable interval for the unknown parameters

A specific type of mesopore extrudates gamma alumina was prepared; which is applied as the catalyst in the heavy oil HYDRODESULFURIZATION unit. Extrudates gamma alumina has been devised the boehmite powder; several samples have been utilized to investigate the concentration and the number of acetic acid treatment effects on the textural properties. Textural properties of catalyst support have been characterized by X-Ray Diffraction, N2-adsorption/desorption techniques, the best results were observed at 25% acetic acid after three times treatments. The active metals (3. 71%Molybdenium &1. 43%Nickle) have been impregnated on the catalyst support. The prepared catalyst determined by X-Ray Fluorescence, N2-adsorption/desorption, bench scale reactor test, NH3-Temperature Programmed Desorption and Radial Strength techniques.

In Iran, power plants use liquid fuels such as heavy fuel oil (HFO) or mazut to prevent disruption in power generation. The high percentage of sulfur compounds in HFO and the lack of efforts to remove it cause significant damage to the environment. The purpose of this research is performing a techno-economic analysis of the HYDRODESULFURIZATION (HDS) process of HFO. The results show that for removing 85% of sulfur compounds from HFO with 3. 5 wt % sulfur compounds at a volume flow rate of 250 m3/h, the total capital investment and the net production cost are 308. 9 million USD and 114. 5 million USD/year respectively. Moreover, the sensitivity analysis indicates that with a 100% increase in the catalyst loading, the mass percentage of sulfur compounds in the HFO decreases by more than 15%, which adds 6. 4% and 32% to the total capital investment and net production cost respectively. With a 100% increase in the gas-to-oil ratio, the mass percentage of sulfur compounds in the HFO decreases by more than 15. 3%, which adds 43. 8% and 6% to the total capital investment and net production cost respectively. With a 100% increase in the pressure of the HDS process, the mass percentage of sulfur compounds in the HFO declines by more than 20. 75%, which adds 43% and 6. 75% to the total capital investment and net production cost respectively. Ultimately, with a 100% increase in the inlet temperature of the beds, the mass percentage of sulfur compounds in the HFO is reduced by more than 5%. Among the effective operational parameters, hydrogen consumption has the greatest impact on net production cost and payback period, and the pressure of the HYDRODESULFURIZATION process has the most significant influence on increasing the total capital investment of the process.