توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Equilibrium Isotherms of Propane and Propylene over Activated carbon
اطلاعات انتشار: دهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۱۵
The adsorption equilibrium isotherms of propane and propylene on two types of activated carbon were measured by a static volumetric technique. Equilibrium data were obtained at (273, 303, and 343) K and pressures up to 1 bar . The porosity was determined by the measurement of the N2 adsorption isotherm at 77 K. Single component equilibrium adsorption of propane and propylene on the adsorbents were correlated by several well–known isotherm models. The enthalpies of adsorption were estimated by Clausius–Clapeyron equation and its dependence on adsorption coverage.The Dubinin–Astakhov equation and Langmuir–Freundlich equations were found to provide an excellent fit to the experimental data.<\div>

۲Theoretical and Experimental Study of Adsorption Separation of O2\N2 on Zeolite 5A
نویسنده(ها): ،
اطلاعات انتشار: همایش بین المللی ژئولیت ایران، سال
تعداد صفحات: ۴
To develop an adsorption separation technology, researches on the adsorption mechanism are necessary
in both theory and experiment. Many researchers have achieved great successes in describing adsorption
behavior by different methods models. In this work, experimental adsorption isotherms of pure oxygen and
nitrogen as well as their mixtures have been obtained with a volumetric method on zeolite 5A. Pure and
binary data are given at temperatures of 273,283, 303, and 343 K and in pressure range 0.05–10 bar. Several
EOS were used for modeling the collected data. The model utilizes the 2–D van der Waals, Soave–Redlich–
Kwong, Peng–Robinson and Eyring equation of state with a classical mixing rule to predict the total
adsorption for the pure and binary systems. Model constants in the 2–D EOS are determined from pure
adsorption equilibrium data and then used to predict adsorption of binary mixtures. The predictions are
compared with experimental data. Comparison of the results from the experiments and the thermodynamic
modeling gave a reasonable agreement.<\div>

۳Four–Bed Pressure Swing Adsorption for Oxygen Separation from Air with Zeolite 13X
اطلاعات انتشار: همایش بین المللی ژئولیت ایران، سال
تعداد صفحات: ۹
This article is presented an experimental and modeling study of a four–bed pressure swing adsorption
process using zeolite13X to provide oxygen–enriched air. The binary mixture N2\O2 (79\21 vol %) was used
as a feed stream. The effects of purge\feed ratio (P\F), adsorption pressure, adsorption time and product flow
rate on product purity under nonisothermal condition were studied. The higher the P\F ratio, the faster
decreasing the purity during long adsorption times. In a constant pressure, for long adsorption times the
purity is decreasing significantly in high P\F ratios (0.18≤ P\F ≤ 0.24). In a constant P\F ratio and pressure,
increasing the product flow rate causes gentle decreasing of purity. Pressure changes have not significant
effect on purity. In cycle time 140 S, P\F ratio = 0.18, pressure = 4 bar, product flow rate = 0.4 lit\min, the
purity of 96.22% is achieved. In this study, the sorption rate into an adsorbent pellet is described by the liner
driving force (LDF) model with a single lumped mass–transfer parameter. A mathlab code using finite
difference method was developed to solve the set of coupled differential–algebraic equations, and the
simulation results are agreed well with experimental results.<\div>

۴Oxidized single–walled carbon nanotubes (SWCNs–COOH) as a newcatalyst for the Oxidation of alcohols
اطلاعات انتشار: اولین کنفرانس ملی نانو فناوری در صنایع نفت، گاز و پتروشیمی، سال
تعداد صفحات: ۵
Nano–materials are considered as suitable heterogeneous catalysts for manyorganic reactions. Herein oxidized carbon nanotube (SWCNTs–COOH) has been reported as a heterogeneous catalyst, for oxidation of alcohol in EtOH at 700C. The+Y59 reactions proceed smoothly with good to excellent yields, and the SWCNTs–COOH used can be recycled.1. Introduction Compounds containing the ketone or aldehyde functional group are important in organic chemistry. They are common in nature and are often key intermediates in organic synthesis . Useful methods for preparation of ketones include the coupling of acid chlorides with organozinc reagents, addition of organomagnesium reagents to Weinreb amides and the hydration of alkynes. Aldehydes can be prepared by reduction of acid chlorides or esters withcertain metal hydrides or by catalytic hydrogenation. Despite numerous methods forpreparation, the single most important method for preparation of both ketones and aldehydes is the oxidation ketones and aldehydes is the oxidation of alcohols. Alcohols are among the most readily available organic compounds, and therefore, this method for preparation of aldehydes and ketones is extremely usefulOn the other hand, materials with nano–sized tubular structures including carbon and metal have been developed.15 Among the nano–structured, carbon nanotube has been a focus of extensive research due to its chemical stability, large surface area, non–toxicity, small dimensions and remarkable physical properties of these materials.16 Carbon nanotubes have showed their potential in many fields.17–19 Along with our previous research on carbon nanotubes,20–22 we now describe another application for carbon nanotubes. Although SWCNTs–COOH has been considered as a suitable heterogeneous catalyst, there are in our opinion no reports for catalytic activity of SWCNTs–COOH. Hence, in this context, wereported a mild and convenient procedure for protection of carbonyl groups by usingSWCNTs–COOH as catalyst. The major advantages of the SWCNTs–COOH as catalyst are: (1) ease of separation from reaction mixture by filtration; and (2) catalyst recycling.<\div>

۵Thermodynamics Modeling of Binary GasAdsorption Equilibria for CO2, CH4, CO and N2 overCarbon Nanotubes
نویسنده(ها): ، ،
اطلاعات انتشار: اولین کنفرانس ملی نانو فناوری در صنایع نفت، گاز و پتروشیمی، سال
تعداد صفحات: ۷
Due to importance of gas adsorption process in diverse fields of scienceand necessity of applying carbon nanotubes in chemical processes,thermodynamics modeling of binary gas adsorption equilibria for CO2,CH4, CO and N2 over some typical carbon nanotubes is investigated.Hence, pure adsorption isotherms of CO2, CH4, CO and N2 on varioustypes of carbon nano tubes were selected from literature data and theirbinary adsorption is predicted using Sips isotherm model combining idealadsorbed solution model. Furthermore, isosteric heats of adsorption arepredicted using an equation derived from Sips model. Binary adsorption ofthe studied systems is characterized using equilibrium x–y diagrams andselectivity curves. Finally effect of temperature and pressure on theselectivity of the considered systems is discussed. The obtained resultsshow that, carbon nanotubes could be applied as a selective adsorbent toseparate all the investigated systems.<\div>

۶Numerical Simulation of a Pressure Swing Adsorption for Air Separation
نویسنده(ها): ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۱۲
A two–bed four step pressure swing adsorption (PSA) using zeolite 5A adsorbent for oxygen separation from air studied by dynamic mathematical simulation. The mathematical model contains partial differential equations corresponding to the bulk gas phase mass, energy and momentum balances. The effects of operational variables such as purge to feed ratio, high operating to low operating pressure and feed flow rate on oxygen purity and recovery were investigated. The results show that in a constant feed flow rate, increasing purge to feed ratio can lead to a reduction the oxygen recovery, but instead will cause to increase the oxygen purity. In the same conditions, increase the feed flow rate will result in a reduction the oxygen purity while the oxygen recovery increases. Results of simulation indicated a very good agreement with some current literature experimental work<\div>
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