Your current location: Home > Industry Info
Industry Info

Key points of formula design for NPK compound fertilizer production line

From a technical point of view, the important factor in the design of the extrusion granulation product formula of a NPK fertilizer production line is the characteristics of the material. Next, we discuss another aspect of the influencing factor, that is, the effect of the type of raw material on the formula.


1.Compatibility of materials
Theoretically, it is possible to formulate basic fertilizers containing NP or K in any proportion, and if necessary, trace elements and even pesticides should be added. However, the materials must be restricted by compatibility. The materials in the formula must not undergo chemical reactions during the fertilizer manufacturing process, and the reactions should not be allowed to occur occasionally.

2.The effect of urea on the formula
The International Fertilizer Center has done a lot of experiments on the effect of urea on the performance of compound fertilizers, although the report has not mentioned the same example as the product formula we are examining, and most of the experiments are not performed on the extrusion granulation method. Yes, but its conclusion is still useful for us.

Because urea is easy to absorb moisture, the critical relative humidity of NPK compound fertilizer is significantly reduced. At the same time, the International Fertilizer Center also found that this effect is even more severe when potassium chloride is used as the potassium source for compound fertilizers.

Because the critical relative humidity is low, urea-based compound fertilizers tend to absorb moisture, which can block screens, pipes, chutes, and so on.

When the temperature rises, the critical relative humidity of urea-based compound fertilizer decreases rapidly.

The production capacity of the dryer must be determined by many factors. Some urea-based NPK fertilizers begin to soften at 70 ° C. If the dryer outlet temperature is higher than this temperature, the fertilizer particles will be too soft and the granulation process will be out of control (too large particles), scarring inside the dryer, and causing difficulties in screening, transportation, etc.

In the same report, the International Fertilizer Center also tested some other aspects of urea, such as: water absorption, moisture permeability, water holding capacity, particle integrity, fluidity, and agglomeration. The result is negative, which has an adverse effect.

In short, the formulation design tests and production of extruded granulated products of compound fertilizer production lines have shown that the use of urea in compound fertilizers will encounter great troubles, not only because of the impact on the storage and transportation performance of the product, but also because it also has a certain impact on the production process.