Mathematical Simulation of Hazardous Ion Retention from Radioactive Waste in a Fixed Bed Reactor

Abstract

Reactor design for fluid-solid, noncatalytic reaction depends on the prediction of the performance of the reactor kinetically. Most mathematical models used to handle a fixed bed reactor in which the solid bed constitutes one of the reactants, while a second reactant is in the fluid phase, are complex and difficult to handle. A new mathematical model which is easier to handle has been developed to describe the system under investigation. The model was examined theoretically and experimentally. A column packed with a chelating cloth filter to separate radionuclides from radioactive waste solution is used as a practical application for the model. A comparison of the model predictions with the experimental results gives a satisfactory agreement at most of the process stages.

Heavy metal extraction by a counter-flow moving bed reactor

“…A further similar increase of the K value provides thus an effective impact on the conversion extent, which can be reasonably understood as this parameter includes the reaction rate constant that is responsible for the speed of reaction. These findings agree with those obtained by Othman et al [1][2][3][4][5]. .…”

“…controlled [1][2][3][4][5]. When ratio is high, the internal diffusion dominates and is the rate determining step so that…”

“…The resin-specific reaction rate parameter can be largely increased by using smaller resin particles [2]. Figure 5 shows that increasing the resin-specific reaction rate parameter largely increases the conversion extent and reduces the required reactor height.…”

“…Similar to other fluid-solid reactors, the global kinetics of the reactor is determined by mass transfer from the bulk fluid to the interior of the solid phase and/or by the chemical reaction. Generally, the internal mass transfer inside the solid particle offers much greater resistance than other steps [1][2][3][4][5], so that it can be considered as the rate-determining step.…”

Experiment and Modeling of Water Vapour Decomposition on ZrNi5 Alloy

“…The following assumptions are made: The fixed bed is isothermal, gas is plus flow and velocity is constant, axial dispersion is negligible for alloy powder size is small compared with the diameter and length of the bed, the reaction is irreversible. One-dimensional quasi-homogenous model of the fixed-bed reactor is based on the conservation equation 12,13 :…”