Ergun Software for Bubbling Beds

TDH and Entrainement

The entrainment from the bed depends on the bubble size at bed surface. To calculate the entrainment coefficients (Ki) and the "Transport Disengaging Height" (TDH) the program propose a number of correlations.

Note that the size distribution of particles at the "top" bed exit is different from that of thebed (almost equivalent to that of the "Discharge" at the lower part). Big particles with a terminal velocity (Ut) superior to the fluidization velocity (U) do not arrive to the top exit if this last one is placed over the Transport Disengaging Height (TDH).

The design of cyclone(s) should be done with this "fine" solid distribution. Note that "fine" particles are always more difficult to capture. A cyclone designed with the bed partcile size distribution would be insuffucient.

The Virtual Expert helps the user to choose the most appropriate model for each case. Results are exposed in a very simple and comprehensive table, as shown in the figure beside.

Ergun Design Technology

Simplified example of solid distibution sizes at diverse level of the bed.

example of results window for TDH and Entrainment module

Links to other pages: Site Map