You use a central dryer as a single source of dry, unheated air that is piped to multiple material hoppers. Each material hopper is equipped with its own heater, blower and controls. The advantage is that you can dry multiple materials with varying drying parameters using the same source of dry air.
Typically, you can use either a dual bed desiccant dryer or a desiccant wheel dryer as the central dryer. You will need several drying hoppers equipped with heaters, blowers and controls. These are supplied as ‘central drying assemblies’. They are connected together with manifolds that carry the dry process air to the drying hoppers and the return air back to the central dryer where that air is re-dried and circulated back to the drying hoppers in a closed loop.