Drying Equipment Dryers for Solids and Pastes Tray

Drying Equipment

• Dryers for Solids and Pastes • Tray dryers • Screen-Conveyor dryers • Tower dryers • Rotary dryers • Fluid-bed dryers • Flash dryers • Dryers for Solutions and Slurries • Spray dryers • Thin-film dryers • Drum dryers

Tray dryers • • • Trays with 30 in 2, 2 to 6 in deep Heated air is circulated at 7 to 15 ft/s Useful when the production rate is small Drying cycles are long: 4 to 48 h per batch Application on valuable products like dyes and pharmaceuticals Dryers for Solids and Pastes

Screen-Conveyor dryers • Typically 6 ft wide and 12 to 150 ft (drying time of 5 to 120 min) • The minimum screen size is about 30 mesh (coarse granular, flaky or fibrous materials) • Particularly applicable when the drying conditions must be appreciably changed as the moisture content of the solid is reduced Dryers for Solids and Pastes

Tower dryers Gas velocities are commonly 2 to 8 ft/s. Dryers for Solids and Pastes

Rotary dryers • Inlet gas temperature are typically 250 to 350 o. F (120 to 175 o. C)steam heated and for flue gas from a furnace 1000 to 1500 o. F (540 to 815 o. C) • Dryer diameters range from 3 to 10 ft (1 to 3 m) Dryers for Solids and Pastes

Fluidized-bed dryers • The average time a particle stays in the dryer is typically 30 to 120 s (only surface liquid is vaporized) and up to 15 to 30 min (internal diffusion) Dryers for Solids and Pastes

Flash dryers • Drying takes place during transportation. • 3 to 4 s is required to evaporate substantially all the moisture from the solid. • The temperature of the gas is high (1200 o. F at the inlet), The temp. of the solid rarely more than 100 o. F during drying. Dryers for Solids and Pastes

Dryers for Solutions and Slurries Thin-film dryers Dryers for Solutions and Slurries Spray dryers

Drum dryers Dryers for Solutions and Slurries