Activity: Talk or presentation › Talk or presentation at a workshop, seminar, course or other meeting
Historically, drinking water engineers have often worked with classical process state prediction models. The most frequently applied and the most popular classical models in l-s fluidisation processes are the Ergun, Carman-Kozeny and Richardson-Zaki models. These semi-empirical porosity prediction models are derived for perfectly round spheres. However, in drinking water multiphase systems, applied particles are often natural - and therefore irregularly shaped. Examples of such particles are calcium carbonate pellets, rapid sand filter grains and granular activated carbon rods, to mention but a few examples. In addition, in these processes, these particles show a non-uniform particle size distribution, which leads to stratified beds in case beds have a fluidised state. The system becomes even more complex when, in pellet softening reactors, calcium carbonate pellets are crushed and re-used for sustainability reasons. To be able to predict bed porosity while considering irregularly shaped particles, an experimental set-up was built at Waternet and at the Applied University in Utrecht. The data obtained from the conducted experiments were compared with the classical models. We were also extremely fortunate to be able to borrow nicely coloured and almost perfectly round mono-dispersed glass beads as a reference, which we were able to compare with our natural sized particles. Jos Vantomme, a Bachelor’s student of Chemical Engineering, has carried out the fluidisation experiments at the HU process laboratory. This was done together with Onno Kramer, a part-time PhD student at TUDelft supervised by co-promotor Johan Padding. During this TUe PhD lecture, we will show the results from liquid fluidisation with the glass beads used at TUe in gas fluidisation experiments.