Improvement of the Richardson-Zaki liquid-solid fluidisation model on the basis of hydraulics (PPT)
Onno J.I. Kramer (Hogeschool Utrecht, Waternet, TU Delft - Sanitary Engineering)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
One of the most popular and frequently used models for describing homogeneous liquid-solid fluidised suspensions is the model developed by Richardson & Zaki in 1954. The superficial fluid velocity and terminal settling velocity together with an index, make it possible to determine the fluid porosity in a straightforward way. To maintain optimal process and control conditions in multiphase drinking water treatment processes, the porosity is kept relatively low. Unfortunately, the Richardson-Zaki index models tend to overestimate the minimum fluidisation velocity and therefore also result in less accurate predictions with respect to porosity values. We extended the Richardson-Zaki model with proven hydraulics-based models. The proposed models are compared with data from expansion experiments with grains applied in drinking water softening using the fluidised bed process. The porosity prediction error decreases from 15% to 3% and the minimum fluidisation velocity error from 100% to 12%.