توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Making support for zeolite membranes from kaolin by extrusion
اطلاعات انتشار: دهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۸
Ceramic membranes specially zeolite membranes are usually used for organics separation by pervaporation. In this research, effect of calcination temperature on flux of kaolin modules that prepared by extrusion as a support of zeolite membranes was investigated. By increasing the kaolin calcination temperature, the flux of membrane increases due to many pores created in the module. This was confirmed by SEM micrographs. The highest flux was about 18 kg\m2.h for modules calcined at 1200 oC with distillated water. Increasing calcination temperature causes module strength to enhance. It was found that the module calcined at 1200 oC may be suitable as a support for zeolite A membranes.<\div>

۲Pervaporation separation of n–hexane\thiophene mixtures with PDMS\PA membrane
نویسنده(ها): ، ،
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۶
The aim of this research is sulfur removal from gasoline by membrane. For this purpose separation of n–hexane and thiophene mixture is investigated by PDMS\PA composite membrane. Effects of feed temperature, permeate pressure, thiophene concentration and feed Reynolds number on the desulfurization efficiency were investigated for binary nhexane\ thiophene mixtures by pervaporation. Experimental results indicated that the change of thiophene concentration has negligible effects on total flux. Total flux slightly increases with increasing feed Reynolds number. With increasing the feed temperature and decreasing permeate pressure, total flux increases. Enrichment factor of thiophene increases by decreasing both feed temperature and permeate pressure. The highest total flux for the n–hexane\thiophene mixture wasobtained at maximum feed temperature (53 ºC) and permeate pressure (46 mmHg) to be 54 kg m–2 h–1. The highest enrichment factor of thiophene was obtained to be 1.42 at a feed temperature of 30 ºC and a permeate pressure of 23 mmHg.<\div>

۳Modeling and Numerical Simulation of Ammonia Stripping from Industrial Wastewater Streams
اطلاعات انتشار: سومین کنفرانس ملی کاربرد CFD در صنایع شیمیایی، سال
تعداد صفحات: ۸
Ammonia removal from water was studied experimentally and theoretically by means of a hollow–fiber membrane contactor (HFMC). Aqueous solution of NH3 flowed as feed in the lumen side of membrane contactor while sulfuric acid was used as stripper in the shell side. An unsteady state and 2D mathematical model was developed to study ammonia stripping in the HFMC. The model was implemented in linked MATLAB–COMSOL Multiphysics. COMSOL software was applied to solve the model equations for the contactor while MATLAB software was employed to consider changes in the feed tank’s concentrations. Modeling predictions were then validated with the experimental data and were found to be in good agreement.<\div>

۴Simulation of CO2 Absorption in Hollow–Fiber Membrane Contactors for Wetting and Non–wetting Modes
اطلاعات انتشار: سومین کنفرانس ملی کاربرد CFD در صنایع شیمیایی، سال
تعداد صفحات: ۷
This study deals with absorption of CO2 in hollow–fiber membrane contactors (HFMCs). Simulations were performed to study CO2 transport through HFMCs. The simulations were performed via CFD techniques based on finite element method (FEM). Simulation results were validated with the experimental data for CO2 absorption using amine aqueous solutions. The simulation results were in consistent with the experimental data. Six liquid absorbents including aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), N–methyldiethanolamine (MDEA), 2–amino–2–methyl–1–propanol (AMP), sodium hydroxide (NaOH) and potassium glycinate (PG) were compared for absorption of CO2. The simulation results showed that the removal of CO2 using aqueous solution of PG was the highest among the other absorbents.<\div>

۵CO2 and CH4 Permeation through SAPO–34 Zeolite Membranes Effect of Synthesis Temperature and Support Properties
اطلاعات انتشار: اولین همایش ملی توسعه تکنولوژی در صنایع نفت، گاز و پتروشیمی، سال
تعداد صفحات: ۶
In this research continuous SAPO–34 membranes were synthesized by secondary growth method onto both –alumina and mullite supports at three levels of synthesis temperature;185,195 and 220 for 24 h. The zeolite membranes synthesized were characterized by XRD, SEM and single gas permeation. It was found out that the support structural properties and synthesis temperature both have significant effects on membrane formation. By increasing synthesis temperature SAPO –34 crystals size which grown on mullite supports become uniform and smaller while crystals formed on a– Al2 O3 substrate become larger. The effect of synthesis temperature on single gas permeation properties of the synthesized SAPO– 34 membranes was also studied The permeance of CH4 and CO2 decreased as the synthesis temperature increased. But the CO2\CH4 ideal selectivity versus synthesis temperature follows two different trends for SAPO–34 membranes synthesized on mullite and a–Al2 O3supports. By increasing synthesis temperature, CO2\CH4 ideal selectivity decreased for – alumina supported membranes while for mullite supported ones increased Under optimum synthesis conditions at room temperature and 1 bar feed pressure the CO2 permeance through – alumina and mullite supported SAPO–34 membranes were 2.01 x 10 –6 and 7.86 x10 –8, , respectively and CO2\CH4 ideal selectivities were 13.91 and17.39 respectively.<\div>

۶Synthesis and Characterization of Thin–layer SAPO–34 Membrane on Disk–Shaped Mullite Support for Natural Gas Sweetaning
اطلاعات انتشار: اولین همایش ملی توسعه تکنولوژی در صنایع نفت، گاز و پتروشیمی، سال
تعداد صفحات: ۸
High reproducibility SAPO– membranes were fabricated on microporous mullite supports via the secondary growth method for the first time. The ceramic supports were prepared via calcination of kaolin powder, followed by a leaching post–treatment. Influence of synthesis temperature on formation of nanoporouse SAPO investigated at three levels: 185,195 and 220 °C. Morphology and crystalline structure of the synthesized membranes were characterized by SEM and XRD, respectively. It was found out that chemical nature of the support and synthesis temperature have significant effects on the nucleation process. The more regular in shape and the less intergrown crystals on the membrane surface layers were observed at higher synthesis temperature. Gas permeation experiments were conducted to characterize the membranes separation ability. Effects of synthesis temperature were also investigated on single permeances of CO2and CH4 and CO2\CH4 ideal selectivity.It was observed that increasing synthesis temperature increases the zeolite layer thickness and eventually decreases the single gas permeances, however, CO2\CH4 ideal selectivity increases as a result of better membrane surface coverage with SAPO–34crystals as confirmed with the SEM results.According to the results of conducted experimental design and at1bar feed pressure, the ranges of gas permeances and CO3\CH ideal selectivities were10 –9to10 –6mol\m2 s Pa) and 5.78–17.39, respectively. Mullite as a novel, cheap and easily processable support was found as a good candidate for synthesis of SAPO–34membranes in separation of CO2 from CH 4.<\div>

۷Synthesis and characterization of W–type zeolite membrane:effect of synthesis temprature
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۱۰
In this paper, effects of synthesis temperature on synthesis of W–type zeolite membrane were investigated. Experiments were carried out at these levels of synthesis temperature: 165, 185 and 200 °C and synthesis time: 12. Permeation measurements and SEM analysis were used forcharacterization of the synthesized membranes. The results showed that increasing synthesis temperature from 165 up to 185 °C increases separation factor of O2\SF6, however, furtherincreasing decreases the separation performance. The same trend was observed for synthesis time for the synthesized zeolite W membrane. This behavior was attributed to the effect of synthesis temperature on selectivity. More zeolite crystals are deposited, and larger crystals are formed at higher synthesis temperatures. Formation of larger crystals increases zeolite layer integration rate,which is responsible for gas separation, in one hand and reduces deposited zeolite layer density, due to the more void formation, on the other hand. In the optimum condition, W–type zeolite membrane was synthesized at 185 °C for 12 h with a high separation factor of 12.<\div>

۸Comparison of T and W zeolite membranes for separation of O2\SF6 mixtures
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۱۱
Greenhouse effect is one of the most significant dilemmas in environmental aspects that cause negative results in nature and society. SF6 is a very potent greenhouse gas. The global warming potential of the gas is 23,900 times greater than that of CO2, and its atmospheric lifetime is about 3,000 years. Two different zeolite membranes (T (0.36 – 0.67 nm) and W (0.27 – 0.51 nm) were synthesized and their performances were evaluated in separation of O2\SF6 mixtures. They were selected due to their different silicon modules (SiO2\Al2O3) and their polarities. Effect of feedpressure on separation of O2\SF6 was also investigated. The results showed that T zeolite membrane (silicon module = 25) provides higher separation factor of O2\SF6 (50) compared withW zeolite membrane (20.1). Also, increasing feed pressure from 3 up to 5 bar decreases separationfactor of O2\SF6 and increases O2 and SF6 permeances through both the zeolite membranes. From the results, it was concluded that increasing pressure decreases the surface diffusion contribution through the molecular sieve pores, and increasing the Knudsen flow and the viscous flow contributions.<\div>
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