The important principle of compound fertilizer production by drum steam granulation is to reduce the addition of water during granulation as much as possible, and moderately increase the temperature and solubility of materials, so as to reduce the heat consumption and improve the qualified rate of pelletizing, increase the output and reduce the production cost of fertilizer production line.
When the granulation temperature and humidity are different from the ambient temperature and humidity, the environmental impact becomes very important and must be adjusted. Because the operation flexibility of rotary drum granulator depends on the adjustment range of granulation temperature, humidity and other factors. The granulation temperature should be controlled between the viscosity temperature and the ambient temperature to maintain a suitable temperature difference, so as to ensure that the materials do not have excessive viscosity and have a certain crystallization rate.
2. Material solubility
In the compound fertilizer with high nitrogen ratio, the amount of urea added exceeds 50%, and the solubility is large, so the amount of liquid phase is very high. It can be improved by adding powdered urea at lower operating temperature. However, the urea dissolution endothermic operation reduces the granulation temperature and increases the granulation difficulty of the rotary drum granulator. In addition, the resulting low-melting-point mixture brings more difficulty to granulation control.
