Q1: Rotary dryers cannot handle __________ materials.

ANS:C - sticky

Rotary dryers cannot handle sticky materials well. Rotary dryers are commonly used in industrial settings to dry bulk solids, such as grains, minerals, chemicals, and biomass. They consist of a rotating drum or cylinder that is heated externally, and the material to be dried is fed into the drum, where it comes into contact with the heated surface and is dried as it rotates. Sticky materials, such as pastes, slurries, or materials with high moisture content and adhesive properties, can pose challenges in rotary dryers. These materials tend to adhere to the surface of the drum, leading to uneven drying, agglomeration, or even blockages within the dryer. Additionally, sticky materials may cause excessive buildup on the drum surface, reducing heat transfer efficiency and overall drying performance. To handle sticky materials in rotary dryers, various modifications or specialized designs may be required, such as the addition of internal lifters or flights to promote tumbling and mixing of the material, the use of air sweep or pneumatic systems to prevent buildup on the drum surface, or the incorporation of agglomeration prevention measures. In summary, while rotary dryers are versatile and widely used for drying a range of bulk solids, they may not be suitable for handling sticky materials without appropriate modifications to mitigate the challenges associated with adhesion and buildup.