DRYING OF SLUDGE-LIGNITE MIXTURE IN A ROTARY DRUM DRYER UNDER SUPERHEATED STEAM

摘要

This paper discusses the drying of partially dried sludge and a sludge/ lignite mixture in a rotary drum dryer.Pouring the sludge directly in to the screw feeder of the rotary drum dryer resulted of a high sticking to the surface of the drum with very large particle size products. The sticking led to a high decline in the drying efficiency and only a very small change in the materials moisture content.Mixing the partially dried sludge with lignite at different ratios led to decrease the sticking to the drum surface however the agglomeration was still a problem.Chopping the mixture of sludge-lignite and then sieving it with 4 mm mesh was the key to eliminate the agglomeration to a great extent. The sieving process introduces the materials to the drum with specific particle size.Controlling the particle size in advance was the solution for preventing agglomeration. This is also led to significant reduction in the moisture content of the product.