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faujasites
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Synthesis and Evaluation of Modified Zeolites for Separation of Acidic Gases
, M.Sc. Thesis Sharif University of Technology ; Khorasheh, Farhad (Supervisor) ; Soltanali, Saeed (Supervisor) ; Ghasabzadeh, Hamid (Co-Supervisor)
Abstract
The adsorption equilibria of carbon dioxide, methane, and nitrogen on pelletized cation-exchanged faujasite zeolite (with alkali, alkaline earth, and transition metal ions) have been investigated by a volumetric apparatus. The standard instrumental analytical techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) coupled with energy dispersive X-ray spectroscopy (EDX), and atomic absorption spectroscopy (AAS) were utilized to characterize binder-free modified zeolites. The EDX spectra and AAS results revealed that the ion-exchange was successfully achieved with expected tendencies. The results indicate that the type of cation present in the zeolite...
Synthesis of Alumina Support Modified with X and Y Zeolites as a Catalyst of Diesel Hydrodesulfurization Process
, M.Sc. Thesis Sharif University of Technology ; Kazemeini, Mohammad (Supervisor) ; Soltanali, Saeed (Supervisor) ; Rashidzadeh, Mehdi (Co-Supervisor)
Abstract
Environmental destructive effects of gases caused by combustion of sulfur compounds in the fuel, poisoning of catalysts, corrosion of equipment, as well as intensification of environmental considerations and new standards adopted for maximum sulfur content has made the desulfurization of fuels important; The desulfurization method using hydrogen has a high potential to remove sulfur. One of the major challenges in this process is to find the proper catalyst that has the best performance for this process. Ni (or Co) Mo (or W)/ γ-Al2O3 catalysts have high potential for using as a catalyst for the desulfurization process from a variety of large-scale or industrial hydrocarbon cuts. According to...
Modeling of catalyst deactivation in zeolite-catalyzed alkylation of isobutane with 2-butene
, Article Chemical Engineering Science ; Volume 65, Issue 2 , 2010 , Pages 645-650 ; 00092509 (ISSN) ; Kazemeini, M ; Khorasheh, F ; Sharif University of Technology
Abstract
The deactivation of solid acid catalysts in liquid phase alkylation of isobutane with 2-butene was investigated. Since under liquid phase conditions the alkylation reaction is severely diffusion limited, effects of diffusion on the rate of reaction and deactivation pathways were considered. In the present work, an attempt has been made to implement more appropriate assumptions in order to properly model catalyst deactivation in a mixed reactor. Accordingly, spatial variation of diffusivity in the pores of the catalyst was considered as a function of time on stream. The effect of the pore mouth plugging was also investigated and it was found that this phenomenon had a pronounced effect on the...
Fabrication of granulated NaY zeolite nanoparticles using a new method and study the adsorption properties
, Article Powder Technology ; Volume 231 , November , 2012 , Pages 1-6 ; 00325910 (ISSN) ; Kazemeini, M ; Ahmadi, S. J ; Kazemian, H ; Sharif University of Technology
2012
Abstract
NaY zeolite nanoparticles were synthesized and shaped into the uniform spherical granules using a developed novel and simple two-step granulation technique. First, the alginate/nanozeolite or alginate/nanozeolite-bentonite spherical hybrid was successfully fabricated, and then the alginate was decomposed by calcinations resulting uniform spherical granules. To improve the mechanical stability of the prepared granules, bentonite was added as an inorganic binder at different ratios of 20wt.% to 40wt.%. Moreover, the effect of binder on the ion exchange properties of the prepared granules was studied. Increasing of binder content from 20wt.% to 40wt.% linearly enhanced the mechanical stability...