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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemical Engineering(IJChE)
- نوع مقاله: Journal Article
- کلمات کلیدی: Alumina,nanocrystal,Selective oxidation,CuO/CeO2,Ultrasound energy
- چکیده:
- چکیده انگلیسی: In this paper, xCuO/CeO2–γAl2O3 nano-catalysts were successfully synthesized by precipitation from an aqueous solution which modified via ultrasonic waves. For characterization of xCuO/CeO2–γAl2O3 samples N2 adsorption results showed that the BET surface area of the CuO/CeO2–γAl2O3, X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-rays (EDX dot-mapping) were used. The BET, XRD and SEM results indicate that CuO/CeO2-γAl2O3 particles are nano-structured catalysts. These catalysts (xCuO/CeO2–γAl2O3) have high specific surface area and finer particle that confirm SEM pictures. xCuO/CeO2-γAl2O3 catalysts compared to other previous synthesised catalysts for selective CO oxidation. The activity and selectivity of these catalysts obtained in the presence of rich hydrogen stream, with space velocity of 30,000 h−1 in the absence of CO2 and H2O. Results show that CuO/CeO2–γAl2O3 catalyst represents high CO conversion in low temperature (less than 120 ◦C), and selectivity of more than 63% at 100 ◦C. Also, results show that decreasing of CeO2 amount decreases selectivity of CO oxidation.
- انتشار مقاله: 28-06-1394
- نویسندگان: Esmaeil Fatehifar,Asadollah Karimi,Reza Alizadeh,Abbas Jafarizad,Mahmood Jamili
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Simulation,Refinery,Atmospheric Distillation Tower,MFCA,Positive Products,Reduce Loss
- چکیده:
- چکیده انگلیسی: The oil refining industry, as one of the most important sources of supply for the people of the world, needs to optimize energy. In the present study, the atmospheric distillation unit of a refinery has been selected as a case study. Using a new method of material flow cost, determining the positive and negative products and their actual valuation, the share of various costs in the unit has been demonstrated. Since about 99.3% of the total costs in this unit are related to the cost of purchasing crude oil as feedstock, the importance of purchasing crude oil in the event of crisis management and the conditions of alternatives are fully characterized. Three crude oils named Maroon, Dezful, and Mansouri were studied as alternatives for Ahwaz crude oil. The results of Maroon crude oil show that, in the same operating conditions, its substitution as the main feedstock obtains the same quality products as Ahvaz crude oil products. The products derived from Dezful crude oil shows a difference of approximately 7 to 8 degrees API. Products from Mansouri crude oil have a difference of between 20°C and 40°C at boiling point and a difference of 5° to 7°API, and with increasing temperature and feed pressure, there is no significant change in the quality of the products. The mixture of Mansouri and Dezful crude oil separately with Ahwaz crude oil does not achieve the desired quality. But proper quality can be obtained by applying changes of 10 °C to 30 °C at inlet temperature, and from 0.5 to 0.7 kg/cm2 at the pressure. Due to the same price of Ahwaz and Maroon and Dezful, there is no change in the cost of purchasing, and products of the same cost are obtained.
- انتشار مقاله: 21-04-1398
- نویسندگان: Asadollah Karimi,Elham Mahmoudi,Esmaeil Fatehifar,Ali Reza Motavalli
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Adsorption,Breakthrough curve,Dynamic modeling,COD removal,Granular Activated Carbon (GAC),Oily waste water
- چکیده:
- چکیده انگلیسی: Bubble column reactors are used in a wide variety of applications such as multiphase bioreactors, catalytic slurry reactors, and absorption processes. The superficial gas velocity-gas holdup relationship and transition point are two important parameters for characterizing the hydrodynamics of a bubble column reactor. In this study, systematic investigation of a nitrogen - water - glass beads bubble column was conducted using the Taguchi experimental design method. The L16 (45) orthogonal array was selected for experiments design. Results showed that the order of importance of parameters is as follows: bed porosity, the ratio of height to diameter, and superficial gas velocity. A novel mathematical model was developed using the experimental data and based on 4th order polynomial. This model was successfully used to obtain the transition point with a high accuracy. The results of the mathematical method were in close agreement with those of the drift flux method. For liquid level of H=12D and slurry content of 13 vol%, transition velocity of 2.98 cm/s was calculated using the presented method, while a velocity of 3.14 cm/s was obtained from the drift flux method.
- انتشار مقاله: 07-06-1390
- نویسندگان: Ali Reza Rouhi,Esmaeil Fatehifar,Leyla Khazini
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: optimization,bimetallic,Modified Fenton,Remediation,tert-butyl mercaptan
- چکیده:
- چکیده انگلیسی: In this work, the fast remediation of tert-butyl mercaptan from the polluted soil via a bimetallic Fenton treatment that included Fe2+/Fe3+/Fe0/Cu2+ in the presence of gasoline was studied. The analysis of variance and the Pareto analysis resulting from the central composite design (CCD) showed that the H2O2, CuSO4, Fe3O4 nanoparticles, nano zerovalent iron (nZVI), and gasoline initial concentrations as a secondary contaminant were influential factors on the removal efficiency of tert-butyl mercaptan (with an effectiveness of 2.09%, 13.38%, 1.92%, 2.01%, and 39.73% respectively). Moreover, the interaction of H2O2/nZVI, H2O2/nFe3O4, H2O2/CuSO4, nZVI/nFe3O4, and nZVI/CuSO4 had a positive effect on removal efficiency, while nFe3O4/CuSO4 had a negative one. Surprisingly, the mixing of nZVI and nFe3O4 before adding them to the reactor did not affect the removal efficiency. The optimum conditions suggested for the maximum removal efficiency of tert-butyl mercaptan were the minimum levels of the initial gasoline concentration (2.5 %w/w), a maximum level of CuSO4 (0.12 %w/w), and an optimum concentration of H2O2, nano-ZVI, and nano-Fe3O4 (8.92 %w/v, 0.1194 %w/w and 0.0898 %w/w, respectively) in the studied intervals. This condition led to a 99.27% efficiency removal of tert-butyl mercaptan removal in 20 minutes without pH and temperature adjustments.
- انتشار مقاله: 01-02-1398
- نویسندگان: Pejman Roohi,Esmaeil Fatehifar
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: optimization,Soil remediation,Sonication,2-methylpropane-2-thiol,Mathematical modelling
- چکیده:
- چکیده انگلیسی: Existence of 2-methylpropane-2-thiol as an organosulfur and odorant compound in the soil could causes environmental problem and social dissatisfaction. In this study, remediation of this type of thiol using ultrasound is investigated. Central Composite Design (CCD) based on Response Surface Model (RSM) was used to obtain effects of the main factor (Power, sonication time and amount of water) and their interactions. Analysis of variance and Pareto analysis shows that all main factors are effective (the percentage effects of 43.30%, 30.35% and 9.62% on removal efficiency for power, sonication time and amount of water respectively). Moreover, interaction between water content and power, and sonication time and power are effective interaction (with P-values of 0.025 and 0.007 respectively). Base on experiment results and analysis of variance effects of the daylight is not significant (P-value=0.825). P-value of lack of fit (0.176) suggested model assessed as a good model and adequately fits data. Highest levels of power and sonication time (86 watt and 38 minute respectively) and water content in lower level (27 ml) in studied interval lead to maximum removal efficiency (82.83%).
- انتشار مقاله: 02-01-1395
- نویسندگان: Pejman Roohi,Esmaeil Fatehifar,Reza Alizadeh
- مشاهده