توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱CFD Optimization of DME Direct Synthesis from Syngas in Experimental Slurry Bed Reactor
نویسنده(ها): ،
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۷
In this research, optimization of direct synthesis of Dimethyl ether experimental reactor considering four main catalytic reactions of production was performed and validated. Effect of temperature, pressure and reactor length on the productivity of reactor was also studied. The reactor was modeled in steady state and isothermal situation. The equations were solved by CFD method of k–e model. The salvation of them for the model was performed separately assuming 10% intensity. Also the impacts of pressure parameters on CO conversion and DME selectivity wereexamined. Then the results were compared with those obtained under H–Mordente Zeolite modified catalyst with Alumina for methanol dehydration reaction and Cuo\Zno\Al2O3 for water gas shift and CO consumption reactions. For each case the maximum error was less than 11%. Taking into account the influence of reactor length increase on its productivity, the results showed that efficient reactor length was 15 cm.<\div>

۲Titanate nanotube: Synthesis, charachterization and future possibilites for removal of heavy metals from aquaeuos solutions
اطلاعات انتشار: چهاردهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۴
Titanate nanotubes (TNTs) are successfully synthesized via a hydrothermal process. These nanotubes with specific surface areas of 194.1 m2g–1 and pore volume of 0.21 cm3g–1 are employed to remove heavy metal ions via adsorption method. TNTs can be synthesised via changing NaOH concentration, temperature, time of reaction and the pH value of washing solutions. In this study, TNTs are synthesized with NaOH concentration of 10 M at the temperature of 130 °C for 96 h and washed with double distiled water and HCl solution of 0.1 M. The characterization of TNTs are investigated by SEM, XRD, and BET analyses.<\div>

۳The Multi–Objective Optimization of Shazand Refinery’s Hydrocracking Unit
نویسنده(ها): ، ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۹
In the process of oil refining, hydro cracking is a process through which a heavy hydrocarbon cut is converted into lighter and more valuable products in presence of hydrogen. The current study isconcerned with a multi objective optimization of several hydro cracking unit’s reactors of ImamKhomeini’s Shazand refinery of Iran. In this regard, a tube reactor in a fixed bed has been modeled and the results validated with industrial data collected from the aforementioned refinery.Then the reactor optimized with the aim of increasing production with respect to the least reduction in the catalytic activity and efficiency in terms of hydrogen and fuel gas consumption. The results indicated that, optimization plus changes in operating conditions led to increased ormaintained conversions at accepted industrial levels. Furthermore, the procedure to reduce the hydrogen consumption complied with led to an estimated annual reduction of 83373.84(KNM 3 ) hydrogen consumptions plus annual saving of about 87120NM3 in heater’s fuel gas consumption. These were economically valuable and in particular, important in terms of environmental issues.Operating parameters varied within ±0.1, ± 0.3, ±0.6, ± 1 and ± 1.2ºC for the reactor inlet temperature for 5%, 10% and 20% by volume of hydrogen injection in the feed and inlet.Optimal variations ranged for the reactor inlet temperature from – 0.7 to +0.3 °C as well as; for inlet hydrogen injection determined to be + 9 to – 9% by volume and for the feed inputs were found +4 to 8% by volume<\div>

۴Mathematical Modelling of Biohydrogen Production in an EGSB Reactor Utilizing Computational Fluid Dynamics
نویسنده(ها): ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۹
In this study the performance of an Expanded Granular Sludge Bed (EGSB) reactor for biological production of hydrogen was modeled using computational fluid dynamics. The effect of differentHydraulic Retention Time (HRT) of 1, 2 and 4 hr and Glucose mass fraction in feed of 0.002,0.004, 0.006, and 0.008 on Hydrogen production rate was determined. The maximum value of H2production rate at the HRT of equal to 2h and Glucose mass fraction of 0.008 is 0.033 kg\h . It wasdemonstrated that the model is capable of predicting the variation of the EGSB reactorperformance for biohydrogen production at various substrate concentrations and HRT values.<\div>

۵A Study of Gas Flow in a Slurry Bubble Column Reactor for the DME Direct Synthesis: Mathematical Modeling from Homogeneity vs. Heterogeneity Point of View
نویسنده(ها): ، ،
اطلاعات انتشار: Journal of Chemical and Petroleum Engineering، چهل و نهم،شماره۱، ، سال
تعداد صفحات: ۱۲
In the present study, a heterogeneous and homogeneous gas flow dispersion model for simulation and optimization of a large–scale catalytic slurry reactor for the direct synthesis of dimethyl ether (DME) from synthesis gas (syngas) and CO2, using a churn–turbulent regime was developed. In the heterogeneous flow model, the gas phase was distributed into two bubble phases including small and large while in the homogeneous one, the gas phase was distributed into only one large bubble phase. The results indicated that the heterogeneous gas flow model was in a better agreement with experimental pilot–plant data compared with that of the homogeneous one. Also, through investigating the heterogeneous gas flow for small bubbles as well as the large bubbles in the slurry phase (i.e.; including paraffins and the catalyst), the temperature profile along the reactor was obtained. The optimum value of rector diameter and height obtained at 3.2 and 20 meters respectively. The effects of operating variables on the axial catalyst distribution, DME productivity and CO conversion were also understudied in this research.

۶Oxidation of H2S to Elemental Sulfur over Alumina Based Nanocatalysts: Synthesis and Physiochemical Evaluations
اطلاعات انتشار: Scientia Iranica، بيست و سوم،شماره۳، ۲۰۱۶، سال
تعداد صفحات: ۱۵
In this paper oxidation of the H2S into elemental sulfur over synthesized alumina–based nanocatalysts was physiochemically investigated and the results compared with a commercial Claus catalyst. The wet chemical, co–precipitation and spray pyrolysis techniques employed to synthesize several alumina nanostructures. Then, the SEM, XRD and ASAP analysis methods utilized to characterize in order to choose the best nanocatalyst. The sulfur andH2S contents determined through the standard UOP techniques. Amongst these as–synthesized materials, Al2O3–supported sodium oxide prepared through the wet chemical and Al2O3 nanocatalyst via spray pyrolysis methods were the most active catalysts for the purpose at hand. In addition, the titanium dioxide nanostructure and a hybrid of nano alumina support (made via the wet chemical method) decorated on the carbon nanotube prepared for this goal. Moreover, the statistical design of experiments screening of the significant synthesizing parameters performed through the Box–Behnken (e.g.;Response Surface Methodology (RSM)) technique. Ultimately, the best chemically characterized nanocatalyst was subjected to evaluations in a fixed bed reactor while effects of temperature, metal loading and GHSV understudied. It was observed that, the alumina nanoparticles prepared through the wet chemical and spray pyrolysis methods led H2S into elemental sulfur in a reproducible manner with 97 and 98% conversions, respectively. Both of these were more desirable than that obtained utilizing the commercial catalysts (i.e.: CR–3S and CRS–31) providing nearly 96% conversion.
نمایش نتایج ۱ تا ۶ از میان ۶ نتیجه