(1) Combined dryers that combine various drying methods, such as spray-fluidized dryers, etc.

　　(2) Combined dryers that combine various heat transfer processes, such as film-fluidized bed dryers, etc.

　　(3) Combination of multi-stage dryers of the same type, such as multi-stage airflow dryers.

　　The combined drying system is often used in the following situations:

　　① When a single drying equipment cannot meet the moisture requirement;

　　②When a single dryer cannot meet the forming requirements;

　　③When using a single dryer with high energy consumption;

　　④When a single dryer cannot control the residence time of the material,

　　⑤When the material has special requirements during the drying process.