A Vertical Fountain Dryer Adjusted for Sawdust and Wood Chips Drying

This article presents the preliminary results on the drying process in a fountain dryer designed and adapted to drying waist sawdust and/or chips of various morphology and moisture content. In terms of drying technology, it is important to reduce the demand for heat and electricity. The phenomena occurring during the drying of sawdust in a fountain dryer were analyzed. Modifications of a typical fountain dryer were proposed in order to dry the chips, to obtain appropriate moisture and quality suitable for the process of their further granulation for the production of pellets. The test stand and the most important properties of the fountain dryer were described and discussed. Such characteristic aims of the device, i.e., efficiency, combustion, air and exhaust gas flow measurements, among others, were presented. The characteristics of the sawdust drying curves as a function of temperature were also determined. Computer simulations of heat exchange, air, and exhaust gas flow velocities were also performed and compared with the results obtained directly from the modified test stand. The maximum combustion of sawdust measured during startup of the furnace was 0.14 m(3)/h, which is 0.46 m(3) of the fuel consumption for the production of 1000 kg. Drying times of wet sawdust is relatively short and takes similar to 50 s for (weight of wet sawdust 4.75 kg, with moisture of 35%) the relatively low air temperature of 175 degrees C.