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چكيده انگليسي :

94 Dynamic Adsorption and Desorption of Chemical Reaction and Mass Transfer Resistance in Packed Beds of Inert Core Hollow Shell Core Monodisperse Spherical Particles an Analytical Solution Ali Fayazbakhsh a fayazbakhsh@ce iut ac ir Date of Submission 2013 06 2 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree Master of Science Language PersianSupervisor Kayghobad Shams K shams@cc iut ac irAbstract Packed bed reactors are widely used in the gas oil and petrochemical industries particularlyfor solid catalyzed heterogeneous reactions in which the packing serves as the catalyst Fixed bedabsorbers desorbers are also ubiquitous within various process industries where because ofphysicochemical limitations traditional separation operations such as distillation solvent extraction crystallization evaporation etc are not applicable For detailed mathematical treatment of thesesystems it is a matter of common practice to consider a bed of monodisperse spherical particles andwrite unsteady state mole balances on both the flowing and the stationary phases and in compliance ofthe physics of the system impose various simplifying assumptions This leads to a system of coupledevolution partial differential equations PDEs that must be solved byanalytical approximation numerical methods depending on the degree of tractability of the coupledPDE s at hand In the last decade fabrication of inert core core shell hollow spherical particles invarious sizes from different materials has proved to be of intense interest The motivations forfabrication of the aforementioned particles are their potential utilization in a wide variety of applicationssuch as drug delivery cosmetics dyes and inks acoustic insulation in the development of piezoelectrictransducers drug encapsulation ultrasound imaging chromatography catalysts fillers coatings adsorptive filters and photonic band gap materials Hollow inert core spherical particles maydemonstrate properties that are remarkably different from those of the core particles It is establishedthat the structure composition and size of these particles can be tuned to tailor their optical electrical thermal mechanical electro optical magnetic and catalytic properties Hollow shell particlesdemonstrate lower density higher specific surface area and particular optical properties To the best ofour knowledge there is no experimental data regarding reactive sorption in packed beds of inertcore shell core hollow spherical particles that can allow simultaneous consideration integration of theseprocesses and mathematical modeling of such systems are scarce and is limited to the use of numericalmethods and simulations In this research the transient behavior of reactive diffusive fixed bed packedwith inert core shell core hollow thin film coated monodisperse spherical rigid particles is investigated We modeled the reactive desorption system with linear mass exchange law between the flowing and thestationary phases The coupled governing partial differential equations were integrated analyticallyusing Laplace transformations The analytical closed form solution involves two infinite integrals Theclosed form solution was integrated using an adaptive integration method and the breakthrough curvesof the system were studied under the influence of the system parameters The limiting cases arediscussed a simple error function type closed form asymptotic solution for fixed bed desorbers withmonodisperse spherical particles is obtained and results are generalized for similar kinetics of reactivefixed bed systems for diffusion absorption into the inert core monodisperse spherical packing Effect ofmass transfer resistance is also investigated Keywords Packed bed Inert core spherical packing Reactive desorption Reactive absorption Reactive diffusion effectivesurface film resistance Reactive diffusion Hollow sphere

فياض بخش، علي

حل تحليلي جذب و واجذبي پويا با واكنش شيميايي و مقاومت انتقال جرم در بسترهاي آكنده از آكنه هاي كروي پوسته اي/ با هسته ي بي اثر

بستر ثابت , فيلم نازك