Air flow can be parallel or counter current to the solids flow. Air flow is typically counter current to solids flow. Wet and pasty materials can be dried when the feed is backmixed with dry product. Air flow is parallel to the solids flow. Because of the short retention time in the dryer, higher outlet air temperatures may be required to achieve low product moistures.
Air flow is perpendicular to solids flow.
Fluid bed dryer can be provided with multiple zones to match the drying operating conditions with the material drying characteristics. Internal heating coils can be provided for additional heat input. Air flow is perpendicular to solids flow. Fluid bed coolers can be provided with internal cooling coils can be provided for additional heat removal. The fluid bed cooler can be the final zone of the fluid bed dryer.