مجله فرآیند نو
پیاپی 64 (زمستان 1397)

In this paper, petrochemical synthesis gas production unit is simulated using Aspen Hysys software and the effect of changing parameters such as temperature and pressure on the output current of the secondary reactor in the unit is investigated. In addition, due to the age of the study unit, the addition of a tri-reforming reactor to increase the production efficiency of petrochemical synthesis gas has been investigated. The results also show that with increasing temperature on the output current of the secondary reactor, the percentage of methane conversion and the ratio of hydrogen to carbon monoxide increase. However, with increasing pressure, the conversion percentage of methane and the ratio of methane to hydrogen also decreases. In addition, by adding a tri-reforming reactor to the unit operating in the temperature range of 800 to 850 ° C, the unit will have the best performance in terms of synthesis gas production.

Nickel catalysts were prepared with different methods and used for hydrogenation of benzene in the refinery platformate. The catalysts were evaluated in a continuous fixed-bed reactor at atmospheric pressure and temperature range of 473-423 K. The physicochemical properties of catalysts were identified by XRD, XRF, FESEM, EDS-map, H2 adsorption and nitrogen adsorption/desorption methods. The effect of hydrogen to benzene ratio and space velocity on catalysts activity were studied. The percentage of nickel particles dispersion is dependent to the method of preparation, the amount of loaded nickel and the interaction between the support and nickel. The catalysts produced by the sedimentation and sol-gel method, 4-6 times more than toluene hydrogenated benzene in the platformate. The highest benzene conversion at 448 K temperature was obtained by catalyst prepared by sedimentation. This catalyst has a better performance in the hydrogenation of benzene due to the greater dispersion and homogeneity of nickel particles.

In the present investigation, the operation of an industrial tray column was evaluated in absorption of hydrogen sulfide by diethanolamine and the effects of processing factors on separation was discussed in detail. In the first step, the absorption process was simulated and the results were compared with the industrial data to validate the calculated method. The role of column pressure, amine concentration, amine inlet temperature and gas flow rate were evaluated on absorption. Although, the increase in column pressure causes to achieve the stream in which the hydrogen sulfide concentration is lower than 0.01 %, the outlet amine temperature increases, negligibly. The rise in amine inlet temperature couldn’t effectively change the operation but amine concentration should be controlled correctly to reach appropriate concentration.

In the present work, the mullite based support was fabricated from Iranian kaolin by extrusion in semi-industrial scale. Firstly, the selected kaolin was extruded by spiral extruder as strand and calcined at 1100 C. In the second stage the amorphous phase was extracted by alkali solution in the presence of microwave to achieve mullite based material. Initially, the change in active site density of supports was evaluated by dye adsorption. X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) techniques were applied to characterize the produced support structure. The obtained results indicated that the fabricated support can be replaced with gamma alumina support. The amorphous phase extraction should be carried out at 1000 W to improve the number of active sites and minimize the weight loss.

Increasing usage of fossil fuels, is polluting environment with an ascending rate. In addition to carbon dioxide, using crude oil leads to emitting sulfur oxides, which in the environment leads to acidification of rainfall and soil and pollution of water resources, and in human can exacerbate heart and respiratory diseases. Moreover, presence of sulfur in petroleum refining is unpleasant since can lead to catalysis deactivation, corrosion of equipment, scale formation, etc. To decrease effects of these pollutants, in many countries environmental regulations are developed to reduce sulfur in petroleum products. The process which is currently used in refineries to reduce sulfur level is hydrodesulfurization. This technology at high temperature and pressure by using hydrogen and in presence of the catalysts, convert sulfur atom in organic compounds to hydrogen sulfide. However, hydrodesulfurization faces with many obstacles and challenges, which in this paper most important issues in this regards are addressed.

Th power generation inKermanshah Oil Refinery Company section includes two parts. The first one is steam power plant and the second one is internal combustion engines power plant. The steam power plant includes two boilers, two turbines, a condenser and feed pumps. Steam power plant has been analyzed using the mass continuity, first law of thermodynamics and the exergy equations. To increase the efficiency of the steam power plant four suggestions have been presented. The first one is reducing the extra supplied air to boiler. The second is using the temperature of exhausted gas from chimney. Third is preheating air by exhausted gas. The last one is preheating the feed water of boiler by the high pressure steam. Results show that increasing 20C in air and 30C in feed water temperature results in saving fuel rate of the boiler by 485000 m3 per year for the company.