Food-Grade PET Flake Pelletizing Case Study: 3000–3500 kg/h High-Capacity rPET Pellet Production Line

Capacity: 3000–3500 kg/h
Raw Material: Washed PET flakes
Finished Product: High-quality rPET pellets
Main Applications: PET sheet, thermoformed packaging, food containers, fiber, packaging products, and other downstream PET applications

PET recycling presents several important processing challenges, especially when washed PET bottle flakes are used as the feed material for high-capacity pellet production.

1. Moisture Sensitivity
PET is sensitive to moisture during thermal processing.
If moisture is not properly controlled, hydrolysis may occur during extrusion, affecting the molecular structure and intrinsic viscosity of the material.
Stable moisture management is therefore an important part of the PET pelletizing process.

2. Intrinsic Viscosity Stability
Intrinsic Viscosity (IV) is an important parameter influencing the properties and downstream processability of PET.
During recycling and extrusion, excessive degradation or unstable processing conditions may result in changes to the material properties.
For this reason, stable extrusion conditions and real-time process monitoring are important for maintaining consistent pellet quality.

3. Residual Contaminants
Even after washing, PET flakes may contain residual contaminants or fine particles.
An effective melt filtration system is therefore required to improve melt cleanliness and support continuous, stable production.

4. High-Capacity Continuous Production
With a production capacity of 3000–3500 kg/h, the complete system must maintain stable material feeding, extrusion, melt pressure, filtration, pelletizing, and process control throughout continuous operation.

Each processing stage must work together to support consistent high-output production.

For this project, ACERETECH designed a complete PET flake pelletizing and extrusion solution based on the customer's production requirements.

The system integrates the following main processing stages:

Crystallization → ACT105/220 Conical Twin-Screw Extrusion → Vacuum Degassing → Automatic Back-Flushing Melt Filtration → Melt Pressure Control → Inline Melt Viscosity Measurement → Underwater Pelletizing → Centralized PLC Control

The complete system is designed to continuously process washed PET flakes and convert them into high-quality rPET pellets.

The process begins with the crystallization of the PET flakes before extrusion.
The crystallization system is designed to improve the flow characteristics of the material and support stable feeding into the downstream extrusion system.

Key functions include:

 Helping prevent material bridging and adhesion
 Improving feeding stability
 Supporting moisture management
 Improving processing efficiency

Proper material preparation before extrusion is important for maintaining stable operation throughout the pelletizing process.

At the heart of this high-capacity PET pelletizing line is the ACT105/220 conical twin-screw extruder.

Main Specifications

 Screw Diameter: 105/220 mm
 Maximum Screw Speed: 75 rpm
 Output: 3000–3500 kg/h

The extrusion system is designed to provide stable processing performance under continuous high-output operating conditions.
Advanced Screw Construction
The screws feature a bimetallic construction combining:
38CrMoAlA nitrided steel
Nickel-based wear-resistant alloy
This design provides:
Excellent wear resistance
Improved corrosion resistance
High-temperature stability
Extended service life
Infrared Heating System
The barrel is equipped with an infrared heating system.
Key advantages include:
Rapid heating
Efficient heat transfer
Reduced energy consumption
Maintenance-free operation
Combined with the air-cooling system, the extrusion unit is designed to maintain stable processing conditions during continuous production.

The high-capacity extrusion system is equipped with a heavy-duty gearbox designed for demanding industrial applications.
The gearbox uses nickel-molybdenum alloy gears to provide stable power transmission during high-output operation.

Key advantages include:

High-torque transmission
Low operating noise
Reliable continuous operation
Extended service life

The robust gearbox supports stable operation of the extrusion system under continuous production conditions.

The extrusion line is equipped with a vacuum degassing system for melt purification during PET processing.

The system includes:

Liquid ring vacuum pump
Roots vacuum booster pump
Multi-stage vacuum configuration

The vacuum system helps remove:

Moisture
Volatile component
Low-molecular-weight substances
By improving melt purification during extrusion, the vacuum degassing system supports stable processing and consistent pellet quality.

After extrusion and melt preparation, the PET melt passes through an automatic back-flushing screen changer.
The system is designed to provide continuous melt filtration while minimizing interruptions caused by frequent manual screen replacement.

Key advantages include:

PLC-controlled automatic cleaning
Continuous production
Improved filtration efficiency
Reduced manual operation
Extended production uptime
This stage is particularly important when processing recycled PET flakes that may contain residual contaminants.

A melt pump is installed downstream of the filtration system.

The main functions of the melt pump include:

Stabilizing melt pressure
Reducing output fluctuations
Supporting consistent pellet production
Improving overall process stability
Stable melt pressure is particularly important for maintaining reliable operation of the downstream underwater pelletizing system.

The system is equipped with an inline melt viscosity measurement system for real-time process monitoring.
The system allows operators to:
Monitor melt viscosity in real time
Observe processing stability
Detect material fluctuations
Adjust processing parameters when required
This monitoring system provides additional support for process control and helps maintain consistent production conditions.

The final pelletizing stage uses an underwater pelletizing system.
The molten PET is processed into pellets under a continuous and automated pelletizing process.

Key advantages include:

Uniform pellet size
Smooth pellet surface
High production efficiency
Effective pellet cooling
Automated operation

The underwater pelletizing system is particularly suitable for continuous high-capacity PET pellet production.

The complete production line is managed through an intelligent PLC control system.

The centralized control system provides:

Centralized operation
Real-time monitoring
Automatic process control
Production data management
User-friendly operation

By integrating the main processing stages into one centralized control architecture, operators can monitor and manage the complete pelletizing process more efficiently.

This high-capacity PET flake pelletizing line integrates multiple processing technologies into one complete system.

Key features include:

Production capacity of 3000–3500 kg/h
Processing of washed PET flakes
PET flake crystallization before extrusion
ACT105/220 conical twin-screw extrusion
Infrared heating and air cooling
Heavy-duty gearbox for continuous operation
Vacuum degassing system
Automatic back-flushing melt filtration
Melt pressure stabilization
Inline melt viscosity monitoring
Underwater pelletizing
Intelligent centralized PLC control

By integrating these technologies into a complete production line, the system is designed to support continuous, stable, high-capacity rPET pellet production.

The rPET pellets produced by this system can be used in a variety of downstream PET processing applications, depending on the final material specifications and application requirements.

Typical applications include:

PET sheet production
Thermoformed packaging
Food containers
Beverage and packaging products
Polyester fiber
PET strapping
Other recycled PET applications
The final application depends on the properties of the recycled pellets and the requirements of the downstream manufacturing process.

Related Articles

PET bottle shredding solutions
PET bottle washing line solutions
PET sheet extrusion lines

This project demonstrates ACERETECH's capability to provide high-capacity PET recycling and pelletizing solutions for the processing of washed PET flakes.
With a production capacity of 3000–3500 kg/h, the complete line integrates material preparation, high-capacity extrusion, vacuum degassing, automatic melt filtration, pressure control, inline viscosity monitoring, underwater pelletizing, and intelligent centralized control.

The complete process can be summarized as:

PET Flake Crystallization → ACT105/220 Conical Twin-Screw Extrusion → Vacuum Degassing → Automatic Back-Flushing Screen Changer → Melt Pump → Inline Melt Viscosity Measurement → Underwater Pelletizing → Centralized PLC Control

By integrating these processing stages into one complete system, washed PET flakes can be continuously processed into high-quality rPET pellets for further manufacturing applications.

Looking for a High-Capacity PET Recycling and Pelletizing Solution?
ACERETECH provides integrated PET recycling and pelletizing solutions covering PET bottle recycling, washing, crystallization, extrusion, melt filtration, pelletizing, and downstream material handling.
Each project can be designed according to the characteristics of the input material, required production capacity, and downstream application requirements.
Contact ACERETECH to discuss your PET recycling project and find a suitable solution for your application.