The blower must push/pull the air through the burner, the ducting to the dryer, the dryer ducting, the slot valves, the fluidized chips, and the exhaust gas cleanup (usually cyclone, but sometimes an additional bag filter) plus the ductwork to and up the stack. Most of this is similar to a rotary dryer or even a belt dryer, but the combined pressure drop of the slot valves and head of fluidized chips may be slightly higher than the other designs.

The normal pressure drop across the dryer bed (and thus across the slots) must be sufficient to distribute the air and maintain the fluid bed state across the whole bed. It is expected that 2” water (xx kPa) would be required, and it could be higher.  In one study there was instability of the fluidized bed along the length of the slot. This is one aspect of the fluidized bed dryer design that needs more work, and a physical model is almost certainly required.

On startup the blower must be able to lift the bed of chips in the dryer (bed head  x bed density). At low flow during startup the other pressure losses will be much lower and the blower pressure should easily lift the bed. The chips near the inlet will be wet and the densest, so it will likely be best to start the fluidization from the inlet end of the dryer. Once a bed is fluidized the flow through the slots can be increased because the pressure above the bed will be lower than the initial slumped back pressure.