Ergun Software for Bubbling Beds

"Step by step"Modeling

Before beginning any design or modeling step, its always interesting to get an idea about the divers properties of solide phase particles (see particle topic). This fisrt step of study is explained in the "Particle" topic and is not discussed here.

The most reasonnable way to beging to design or study a fluid bed is to study the "Hydrodynamic" behaviour first. "Heat Balance" and "Reaction Rate" calculations are usually done in second and third steps of the design study. As shown in the figure beside, divers steps of calculation are :

Grid check

Bubbling and expansion properties calculation

"Transport Disengaging Height" calculation and population balance on the fluid bed

Cyclones design and study

Heat Transfer Coefficient calculation and bed Heat Balance

Conversion rate calculation (depends on bubbling properties and solid residence time)

This preliminary step by step calculation helps us to avoid "Interactive Design Problems" confusion. For example, if the fluidization grid is not well designed bubbles may become big and the "mass transfer rate" between the bubbles (gas) and the so called suspension (solid) phases becomes poor. This would lead to a poor conversion rate of the reaction. "Step-by-step" preliminary study helps us to avoid such a complecated interactions.

Once these steps of calculations are finished, the project can be put together byn FBmod expert modeling module.

Ergun Design Technology

Step by step calculation procedure proposed for a design task

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