Moisture standard for fertilizer drum steam granulation
The drum granulator is a commonly used fertilizer production machine. In the steam granulation process, the pellets are mainly clad, so the material circulation volume should be larger, so this can provide a larger coating process Nuclear, and the water injection volume should be smaller, so that the water absorption of the core can be reduced. When pelletizing by bonding or "gathering", the moisture content of the material is smaller, because at this time, the material in the rotary drum is mainly composed of fresh materials with small particle size and mutual bonding. The liquid ratio required for bonding should be large, because the space between the fine powder particles to be bonded with each other should be filled with water.
The main structure of the rotary drum granulator is an inclined rotary cylinder, the drive can be constant speed or variable speed. When the liquid content of the feed powder is appropriate, agglomeration occurs and rolls in the drum. The drum has a certain slope, and the included angle between its axis and the horizontal is below 10 °, which can help the material roll along the long direction of the drum. The feed end is often equipped with a retaining ring to prevent the material from flowing back. A retaining ring can also be installed at the discharge end of the drum granulation production process to increase the thickness of the material layer and extend the residence time in the main drum. In other occasions, a spiral discharge ring is often used to convey boredom to the drum. At the end of the screen. Sometimes the cylindrical screen is integrated with the drum to form a product discharge port.
In the whole NPK fertilizer manufacturing process, the feed consists of fresh material and circulating material, and the feeding system can adopt belt conveyor, chute pipe or other similar equipment. The bonding liquid is injected either before the solid material enters the rotating cylinder or immediately after the solid enters the rotating cylinder.