In the NPK (nitrogen phosphorus potassium) fertilizer production line, granulation is a key process that converts raw materials into granular fertilizers that are easy to store, transport, and use. According to different process requirements and production capacity, there are several types of common granulator equipment:
The disc granulator is the most traditional granulation equipment, suitable for large-scale continuous production. It forms spherical particles of material through the centrifugal force generated by rotating the disk. Suitable for processing powder raw materials with good fluidity.
Features: Simple structure: easy to operate and maintain. High flexibility: The particle size can be changed by adjusting the disc angle and speed.
Extrusion granulators are divided into two types: single axis spiral extruders and double axis roll extruders. Among them, the roller extrusion granulator is particularly suitable for granulating high hardness and high viscosity materials, such as some NPK fertilizer raw materials.
Characteristics: High pressure extrusion: By squeezing between two pairs of rotating rollers, solid particles are formed.
Wide applicability: capable of handling diverse raw materials, including those that are not easy to flow or have a certain viscosity.
3. Fluidized bed granulator
Fluidized bed granulation is a process of granulation carried out under fluidized conditions, particularly suitable for granulation of high humidity raw materials. By spray liquid into the fluidized bed, the particles will gradually grow up by tumbling in the airflow.
Features: Simultaneous drying and granulation: Especially suitable for raw materials with high moisture content, drying can be completed simultaneously with granulation. Particle uniformity: forming a relatively uniform particle size distribution.
4. Efficient mixing and granulation machine
This granulator integrates mixing, granulation, and drying, making it particularly suitable for situations that require fast and continuous production.
Features: Multi functional integration: simplifies the process flow and reduces energy consumption. Easy to operate: high level of automation, easy to adjust granulation conditions.
5. Particle cooler/dryer
Although not a direct granulation equipment, it is crucial in NPK fertilizer production lines for cooling and drying freshly produced particles, ensuring their stability and storage performance.
characteristic:
Ensure quality: prevent particles from deforming or sticking due to high temperature or humidity.
Improve efficiency: shorten production cycles and increase overall production line capacity.
The choice of type of granulator depends on various factors such as raw material properties, expected output, energy consumption, and economic costs. In practical applications, enterprises may also combine multiple devices to meet specific production needs through customized design. For example, in the NPK fertilizer production line, a roller press granulator may be used for initial shaping, followed by refinement and drying using a fluidized bed granulator, and finally cooled using a particle cooler to obtain high-quality granular fertilizers.