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Pore Model (pore + model)
Selected AbstractsDiffusional properties of chitosan hydrogel membranesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2001Barbara Krajewska Abstract Chitosan membranes were prepared by a solvent evaporation technique, followed by crosslinking with glutaraldehyde and coating with BSA. The effects of crosslinking and BSA coating on the pore structure of such prepared hydrogel chitosan membranes were determined. The diffusion rates of 12 non-electrolytes ranging in molecular radius between 2.5 and 14,Å through the membranes were measured, and the results were interpreted in terms of the capillary pore model and free volume model of solute diffusional transport through hydrogel membranes. Glutaraldehyde crosslinking was found to reduce the membrane water content and consequently the membrane pore size and surface porosity, whereas further BSA coating brought about the opposite effect. The latter effect lessened with an increase in glutaraldehyde pretreatment of the membranes. The optimal chitosan membrane preparation, compromising between the solute flux and membrane stability and durability was obtained when the membranes were crosslinked with glutaraldehyde at concentrations between 0.01 and 0.1% (w/w). The knowledge of transport properties and of physical strength of the membranes is of importance for the development of chitosan-based controlled release systems. © 2001 Society of Chemical Industry [source] Application of the random pore model to the carbonation cyclic reactionAICHE JOURNAL, Issue 5 2009Gemma Grasa Abstract Calcium oxide has been proved to be a suitable sorbent for high temperature CO2 capture processes based on the cyclic carbonation-calcination reaction. It is important to have reaction rate models that are able to describe the behavior of CaO particles with respect to the carbonation reaction. Fresh calcined lime is known to be a reactive solid toward carbonation, but the average sorbent particle in a CaO-based CO2 capture system experiences many carbonation-calcination cycles and the reactivity changes with the number of cycles. This study applies the random pore model (RPM) to estimate the intrinsic rate parameters for the carbonation reaction and develops a simple model to calculate particle conversion with time as a function of the number of cycles, partial pressure of CO2, and temperature. This version of the RPM model integrates knowledge obtained in earlier works on intrinsic carbonation rates, critical product layer thickness, and pore structure evolution in highly cycled particles. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Kinetic study of the gasification of an Australian bituminous coal char in carbon dioxideASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2010Chetan R. Chodankar Abstract Experimental work was carried out to study the kinetics of the carbon dioxide gasification of a coal char. The coal char was prepared from an Australian bituminous coal by pyrolyzing it at 900 °C in a tube furnace for 9 min in inert environment. The coal char was gasified in a thermo-gravimetric analyzer (TGA) with a mixture of carbon dioxide and nitrogen. The effects of gasification temperature (800,875 °C) and carbon dioxide concentration (10,80%) were studied. In the present study the reaction rate of the pyrolyzed coal was obtained and interpreted by Random pore model. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | ||||||||||