Process Description for Pelletizing and Extrusion in Compound Feed Processing Units

Compound feed processing unit The manufacturing process can be summarized as follows: raw material receiving and cleaning → crushing → batching → mixing → shaping → metering and packaging, among other key steps. Feed shaping typically involves processes such as pelleting, extrusion, and compression. Next, let’s take a look at… Compound feed processing unit Process description for granulation and extrusion.

1. Compound feed processing unit Process of granulation and pelletizing
Traditional pelletizing processes involve pelleting, cooling, crushing, and grading. This method is typically used to produce animal feed or other low‑energy feeds, with the resulting product usually being loose. Nowadays, some plants employ much more sophisticated pelletizing processes, which comprise the following processing steps:
During the aforementioned process, tempering and annealing promote starch gelatinization and protein denaturation, thereby enhancing the nutritional value of the feed and improving the material’s pelleting performance, which in turn elevates the processing quality of the pelletized product. Following quenching and tempering, the starch undergoes gelatinization; the gelatinized starch acts as a lubricant as it passes through the die holes, and during pellet formation, it fills the voids between the various ingredients, binding them together to produce a compact, dense product.
2. The factors affecting granulation quality and bulk density are, respectively,
Feed formulation accounts for 40%, feed ingredient particle size accounts for 20%, and processing technology accounts for 40% (including conditioning and tempering at 20%, ring-die pelleting at 15%, and cooling and drying at 5%).
3. Compound feed processing unit Process Granulation Quality Control Technology
In this regard, first, it is essential to control the quality of feed conditioning—specifically, temperature, processing time, water addition, and the degree of starch gelatinization—to ensure that the conditioned feed is suitable for pelleting. Second, it is necessary to regulate the feed‑in rate of hard pellets, the cooling temperature, moisture content, pellet uniformity, consistency, and water resistance. To meet these requirements, a well‑designed steam supply and control system, along with appropriate conditioning, pelleting, cooling, and screening equipment, must be in place, and process parameters should be scientifically adjusted according to the specific needs of each product.
4. Expansion Principle
Extrusion puffing is a process in which materials are moistened, heated, and tempered, then forced through an extrusion die or abruptly released from a pressurized vessel, causing their volume to expand due to the sudden drop in pressure. During this expansion operation, the material is subjected to heat and pressure; when no steam or water is used, the process is referred to as dry puffing. When steam or water is added during heating and pressurization, the resulting expansion is called wet puffing. In feed production, the commonly employed extrusion puffing technique involves conditioning and tempering the material, continuously applying pressure and extruding it, followed by a rapid pressure release to induce volumetric expansion. The primary piece of equipment used is the screw extruder.
5. Compound feed processing unit Puffing process technology
Extruded feed is the primary form of extruded feed production. While the processing steps may vary depending on the type of extruded feed being produced, the process typically involves several stages, including crushing, screening, batching, mixing, tempering, extrusion, puffing, drying, cooling, coating, and final product packaging.