The amino acid (feed bed reaction) process is used to produce compound fertilizers. It is in principle between the pellet method and the slurry method. The produced products have smooth and smooth particles, high strength, and are not easy to agglomerate. In production, it has strong adaptability to raw materials and formulas. The product has wide adaptability and little side effect on soil.

In the process of liquid ammonia and sulfuric acid, sulfuric acid is sprayed on the surface of the material. The rate of ammoniation of the acid is mainly controlled by the diffusion rate of ammonia molecules approaching the outside of the particles and then entering the pores from the surface. Production practice shows that the flow state of ammonia passing through the bed can be divided into two types: one is the filtration type, which continuously flows through the gap between the particles, hardly affecting the movement of the particles; the other is the spray type, where the ammonia passes The nozzle has a large flow velocity, which forms a space or a tongue in the particle bed, causing the particles to make a violent rotary motion, which greatly strengthens the mass and heat transfer process.

Liquid ammonia is sprayed uniformly along the axis of the granulator through a distributor buried in the bed. Good design can make the absorption rate of ammonia reach over 95%. Ammonia distributor is an important part of ammonia granulator. From the perspective of perennial operation at home and abroad, the technology is mature and secure.