Abstract: Porous, moisture-containing materials are dried in a fluidized bed reactor. The moisture content of both the underflow and carryover products from the dryer are controlled by introducing hot gases into the freeboard region above the fluidized bed. One or more tuyeres of extended length with ports at a level above the fluidized bed in the freeboard regin may be employed to admit hot gases directly into the freeboard region from the reactor windbox without traversing the fluidized bed. Alternatively, a valved conduit may be employed extending through the refractory dome or gas distributor to regulate gas flow between the windbox and the freeboard region.