(1) melt extrusion

Clean polyester chips from recycling and cleaning are fed into a hopper, and after metal impurities are removed by a metal detector, they are quantitatively fed into an annular extruder by a metering feeding device. The raw materials without pre-drying enter the extruder for continuous mixing and uniform heating. The polyester chips are degassed first in solid state, dried to a certain water content, and then melted and homogenized. By vacuum and contact degassing of the melt with high surface renewal rate, the organic components in soft drinks, such as aromatic or other diffused solvents, which may cause toxic effects on polyester bottles, are carried out by airflow and removed, so that the melt can obtain the required cleanliness and hygiene. The PET melt is pressurized by a gear pump, and continuously passes through a melt filter to remove solid particles, so as to be granulated.

(2) casting belt and granulating

The qualified melt is extruded through a casting head to form a uniform strip, cooled in a water bath, cut into particles of a specified size by a granulator, that is, sliced, and then air-dried. The unqualified particles are removed by vibration screening, and the qualified chips are transported to the crystallization device in the solid phase polycondensation section by air flow.

(3) crystallization

It is a two-step fluidized bed crystallization process. Amorphous polyester chips are heated to above 130℃ for pre-crystallization, and crystallized in closed air not exceeding 180℃. In the fluidized bed, the chips are prevented from sticking by airflow disturbance, and the surface moisture is removed, without hydrolysis, and the chips are dried.

(4) solid phase polycondensation

In the solid-state polycondensation reactor, the polymer is heated to above 200℃ to reach the temperature required for initial polycondensation, which completes the second crystallization and is also dried to a very low water content. The process of continuous solid-state polycondensation and thickening with high-purity hot nitrogen gas, by controlling the temperature and residence time of the polymer in the reactor, the final viscosity reaches the required bottle-level slicing standard, and any impurities and pollutants are removed during this process. The reacted nitrogen gas is subjected to catalytic oxidation to remove organic impurities, which ensures its recycling. The chips coming out of the solid-state polycondensation reactor are cooled and transported to the finished product warehouse by airflow. The recycled polyester bottle-grade chips are weighed and packaged by the automatic packaging system, and the chips are packaged and sent to the finished product warehouse.

Polyester bottle brick → unpacking and feeding → drum impurity removal → label removal → automatic sorting → whole bottle cleaning → label removal → automatic sorting → manual sorting (metal removal) → crushing → floating washing → hot washing → friction dehydration → washing → rinsing → drying → chip sorting → clean polyester chips → packaging.