Multistage hot gas dryer for conveyed bulk prod. - recovers low grade waste heat from industrial process, used e.g. in sugar refineries

摘要

Drying is carried out in several successive stages, each effected in one of several, superimposed conveying compartments. Each compartment houses a conveyor band permeable to hot gas which is supplied at 100 degrees C. In each compartment, hot gas is blown through a conveyed layer of prod. which is discharged into the next stage, or from the final stage. Successive stage conveyors carry progressively thicker layers of prod., each at a slower speed than the previous one. In each stage prod. layer thickness and conveyor speed are pref. adjustable. The hot gas is pref. supplied from a heat exchanger where waste heat from an industrial process raises the temp. of the gas. In every stage but the last, prod. layer thickness and conveyor speed pref. ensure saturation of the gas after passage through the layer. In the last stage, conditions are adjusted to obtain a final prod. of desired moisture content. Used for drying industrial prods. in bulk, e.g., beetroot pulp in sugar refineries. Low grade waste heat below 100 degrees is used to dry the prod. while the process is used to cool waste industrial fluids prior to disposal. Drying is rapid and efficient with no danger of overheating the prod.