Abstract: Disclosed are a multi-stage gravity-type sludge drying apparatus and a sludge drying method using the same. The drying apparatus includes: a dryer, a preheater, a steam generator, a filter, a steam or water separation buffer tank, a steam compressor, a cooling water pump, a sealed discharge device, pipes and valves. The dryer includes several indirect dryer modules. The transportation of sludge in the dryer is achieved by gravity. The inner cavity of respective indirect dryers is filled with high-temperature steam to dry the sludge by indirect heating. The condensate water in the cavity is recycled and fed into the preheater to perform preheating and impurity removal on the wet sludge. The secondary steam generated in the dryer is filtered, compressed and overheated to become a new heat source for indirect heating in the cavity and convection drying at a bottom of the dryer.

Abstract: Disclosed are a multi-stage gravity-type sludge drying apparatus and a sludge drying method using the same. The drying apparatus includes: a dryer, a preheater, a steam generator, a filter, a steam or water separation buffer tank, a steam compressor, a cooling water pump, a sealed discharge device, pipes and valves. The dryer includes several indirect dryer modules. The transportation of sludge in the dryer is achieved by gravity. The inner cavity of respective indirect dryers is filled with high-temperature steam to dry the sludge by indirect heating. The condensate water in the cavity is recycled and fed into the preheater to perform preheating and impurity removal on the wet sludge. The secondary steam generated in the dryer is filtered, compressed and overheated to become a new heat source for indirect heating in the cavity and convection drying at a bottom of the dryer.