In the field of continuous bulk solids processing equipment, residence time can be one of the most influential variables in process Settings, especially when handling materials in rotary dryers, rotary kilns, drum granulators, or other types of drum.

Residence time is the amount of time a material is processed in a given device. In most process Settings, a specific retention time must be achieved to achieve its intended goal. Such as the need to achieve a specific moisture content, to initiate or complete a chemical reaction or phase transition, to form particles within the desired size distribution, and so on.

For example, in terms of mass, a rotary dryer that does not properly understand retention time may cause the material to reach the target moisture content too early in the drum, meaning that the material will continue to dry for the remaining time. This can cause the material to over-dry and break down into fine powder. Similarly, if the length of the drum is insufficient to accommodate the necessary retention time, the material may leave the drum before reaching the desired moisture content, still falling short of the desired target particles. In other cases, the mass may not be affected, but the drum size may be too large, resulting in reduced efficiency. Therefore, in the production process of npk fertilizer line, we should control the time rhythm and pay more attention to the temperature, humidity, size and form of materials.