In an era of increasing environmental awareness and stringent resource conservation policies, plastic recycling has become a critical focus for industries worldwide. Among the various plastic recycling technologies, waste plastic recycling granulation stands out as a practical, efficient, and economically viable method that transforms discarded plastic materials into reusable granules. These recycled granules can be further processed into new plastic products, with performance levels comparable to those made from virgin materials, thus realizing true resource circulation and reducing the environmental burden caused by plastic waste.
Zhuoyue, a leading manufacturer of extrusion equipment, is committed to providing comprehensive recycling granulation production lines for all types of waste plastics, including PP (Polypropylene), PE (Polyethylene), LDPE (Low-Density Polyethylene), PET (Polyethylene Terephthalate), PS (Polystyrene), ABS (Acrylonitrile Butadiene Styrene), and more. With advanced extrusion technology and in-depth expertise in plastic recycling, Zhuoyue’s extruders are tailored to meet the unique challenges of waste plastic granulation, delivering efficient, energy-saving, and high-quality solutions for enterprises engaged in plastic recycling.
1. An Overview of Waste Plastic Recycling Granulation
Waste plastic recycling granulation is a specialized process that converts various forms of waste plastics—such as plastic bottles, films, containers, scraps from production lines, and post-consumer plastic waste—into uniform, high-quality plastic granules through a series of mechanical and thermal treatments. These recycled granules, also known as regranulates or reprocessed plastic pellets, can be directly used in injection molding, extrusion, blow molding, and other plastic processing methods to produce new products, ranging from packaging materials and construction components to automotive parts and daily necessities.
The core value of waste plastic recycling granulation lies in its ability to address the dual challenges of plastic waste disposal and resource scarcity. Unlike traditional waste plastic disposal methods such as landfilling and incineration, which pose severe environmental risks, recycling granulation achieves true resource recycling:
- Environmental Protection: Landfilling of plastic waste occupies valuable land resources and can lead to soil and groundwater pollution, as plastics are non-biodegradable and can release harmful substances over time. Incineration, on the other hand, emits toxic gases (such as dioxins and carbon monoxide) and particulate matter, contributing to air pollution and global warming. Recycling granulation reduces the amount of plastic waste entering landfills and incinerators, minimizing environmental pollution and carbon emissions.
- Resource Conservation: Plastics are derived from non-renewable fossil fuels (such as oil and natural gas). By recycling waste plastics into reusable granules, the demand for virgin plastic materials is reduced, conserving valuable fossil resources and reducing the energy consumption associated with virgin plastic production. It is estimated that recycling one ton of plastic can save up to 7.4 barrels of oil and reduce carbon emissions by 1.5 tons.
- Economic Benefits: Recycled plastic granules are significantly cheaper than virgin plastic materials, offering substantial cost savings for manufacturers. For recycling enterprises, the process of collecting, processing, and granulating waste plastics can generate stable profits, creating new economic opportunities and employment positions. Additionally, many countries and regions offer policy incentives (such as subsidies and tax breaks) for plastic recycling enterprises, further enhancing the economic viability of recycling granulation.
However, the quality of recycled plastic granules and the performance of the final recycled products are highly dependent on the granulation process and equipment used. Factors such as the type and purity of waste plastic, the efficiency of sorting and cleaning, the temperature and shear control during extrusion, and the design of the extruder all have a significant impact on the final product quality. Therefore, developing a simple, convenient, efficient, energy-saving, environmentally friendly, and economically viable granulation process has become the focus of research and development in the plastic recycling industry.
1.1 Key Characteristics of Recycled Plastic Granules
The performance of recycled plastic granules is closely related to the type of waste plastic, the degree of contamination, and the granulation process. In general, high-quality recycled granules should possess the following characteristics:
- Uniform Particle Size: Consistent particle size ensures stable feeding during subsequent processing (such as injection molding and extrusion), improving the uniformity and quality of the final product. The particle size of recycled granules is typically between 2mm and 5mm, depending on the application requirements.
- Low Contamination: Contaminants such as dirt, dust, metal fragments, paper, and other non-plastic materials can significantly affect the performance of recycled granules and the final product. Therefore, effective sorting and cleaning of waste plastic are essential to ensure low contamination levels.
- Good Plasticity and Processability: Recycled granules should have good melting properties and flowability, allowing for easy processing into new products without affecting the processing efficiency or product quality. This requires precise control of the temperature and shear rate during the granulation process to avoid excessive degradation of the plastic molecular structure.
- Stable Mechanical Properties: The tensile strength, elongation at break, impact strength, and other mechanical properties of recycled granules should be as close as possible to those of virgin materials, ensuring that the final recycled products meet the required performance standards.
- Low Moisture Content: High moisture content in recycled granules can lead to defects such as bubbles and cracks in the final product during processing. Therefore, drying steps are often required during the granulation process to reduce the moisture content to an acceptable level (typically below 0.5%).
1.2 Common Types of Waste Plastics for Granulation
Almost all types of thermoplastic plastics can be recycled and granulated, while thermosetting plastics (which cannot be melted and reprocessed) are not suitable for recycling granulation. The most common types of waste plastics used in recycling granulation include:
- PP (Polypropylene): A widely used thermoplastic with good chemical resistance, mechanical properties, and processability. Common waste PP includes plastic buckets, containers, caps, and production scraps. Recycled PP granules are often used to produce plastic pipes, auto parts, and packaging materials.
- PE (Polyethylene): Divided into LDPE (Low-Density Polyethylene) and HDPE (High-Density Polyethylene). LDPE is commonly used in plastic films, bags, and bottles, while HDPE is used in barrels, pipes, and containers. Recycled PE granules are suitable for producing plastic films, pipes, and injection-molded products.
- PET (Polyethylene Terephthalate): A transparent, rigid plastic commonly used in beverage bottles, food packaging, and fiber products. Recycled PET granules are widely used in the production of polyester fibers, plastic bottles, and packaging materials.
- PS (Polystyrene): Available in rigid (such as foam cups, food containers, and plastic toys) and foam (EPS, expanded polystyrene) forms. Recycled PS granules can be used to produce plastic toys, decorative materials, and foam products.
- ABS (Acrylonitrile Butadiene Styrene): A high-performance plastic with good impact strength, rigidity, and heat resistance. Common waste ABS includes plastic shells of electronic products, auto parts, and toys. Recycled ABS granules are used to produce electronic product shells, auto parts, and injection-molded components.
Zhuoyue’s recycling granulation production lines are designed to handle all the above-mentioned waste plastics, with customized equipment configurations to meet the specific processing requirements of different plastic types.
2. The Waste Plastic Recycling Granulation Process
The waste plastic recycling granulation process typically consists of several key steps: waste plastic collection and sorting, cleaning, crushing, drying, extrusion granulation, cooling, and cutting. Each step plays a crucial role in ensuring the quality of the final recycled granules. The specific process parameters may vary depending on the type of waste plastic, the degree of contamination, and the desired quality of the recycled granules.
2.1 Collection and Sorting
The first step in the recycling granulation process is the collection and sorting of waste plastics. Waste plastics are collected from various sources, including households, industries, commercial establishments, and production lines. Due to the wide variety of waste plastics and the presence of contaminants, sorting is essential to ensure the quality of the recycled granules.
Sorting can be done manually or mechanically. Manual sorting is suitable for small-scale recycling operations and involves separating different types of plastics, removing non-plastic contaminants (such as metal, paper, glass, and organic waste), and sorting plastics by color and quality. Mechanical sorting, on the other hand, is more efficient and suitable for large-scale operations, using technologies such as density separation (sink-float separation), magnetic separation, electrostatic separation, and infrared sorting to separate different plastic types and remove contaminants.
Effective sorting is critical because mixing different types of plastics can lead to a significant reduction in the performance of the recycled granules. For example, mixing PP and PET can cause phase separation during extrusion, resulting in poor plasticity and mechanical properties of the granules.
2.2 Cleaning
After sorting, the waste plastics are cleaned to remove surface contaminants such as dirt, dust, oil, grease, food residues, and labels. The cleaning process typically involves several steps:
- Pre-cleaning: Removing large contaminants (such as labels, caps, and metal fragments) and coarse dirt through brushing, blowing, or manual picking.
- Washing: Soaking the waste plastics in a cleaning solution (usually water with detergent or alkali) to remove oil, grease, and food residues. Agitation or ultrasonic cleaning may be used to enhance the cleaning effect.
- Rinsing: Rinsing the cleaned plastics with clean water to remove any remaining cleaning solution and contaminants.
- Dewatering: Removing excess water from the cleaned plastics using centrifuges, dewatering machines, or air drying to reduce the moisture content and facilitate subsequent processing.
The cleaning effect directly affects the quality of the recycled granules. Inadequate cleaning can lead to contamination of the granules, affecting their processability and mechanical properties. For example, oil and grease residues can cause poor adhesion between the plastic molecules during extrusion, resulting in low tensile strength of the granules.
2.3 Crushing
After cleaning and dewatering, the waste plastics are crushed into small pieces (flakes or fragments) using a crusher. Crushing helps to increase the surface area of the plastic, facilitating melting and mixing during the extrusion process. It also helps to remove any remaining small contaminants that may be embedded in the plastic.
The type of crusher used depends on the type and form of the waste plastic. Common types of crushers include jaw crushers, hammer crushers, blade crushers, and granulators. For flexible plastics (such as plastic films and bags), blade crushers are typically used, while for rigid plastics (such as plastic bottles and containers), hammer crushers or jaw crushers are more suitable. The size of the crushed plastic pieces is usually between 5mm and 20mm, depending on the type of extruder used and the desired granule size.
2.4 Drying
Even after dewatering, the crushed plastic pieces may still contain a certain amount of moisture. High moisture content can lead to defects such as bubbles, cracks, and poor surface quality in the recycled granules during extrusion. Therefore, a drying step is necessary to reduce the moisture content of the crushed plastic pieces to an acceptable level (typically below 0.5%).
Common drying methods include hot air drying, vacuum drying, and infrared drying. Hot air drying is the most widely used method, which involves passing hot air (at a temperature of 80-120°C) through the crushed plastic pieces to evaporate the moisture. The drying time and temperature depend on the type of plastic and the initial moisture content. For example, PET is more sensitive to moisture and requires higher drying temperatures (120-160°C) and longer drying times to ensure complete moisture removal.
2.5 Extrusion Granulation
Extrusion granulation is the core step in the waste plastic recycling granulation process. It involves melting, mixing, and homogenizing the dried crushed plastic pieces using an extruder, then extruding the molten plastic through a die to form continuous strands, which are subsequently cooled and cut into uniform granules.
The extruder is the key equipment in this step, and its performance directly determines the quality and efficiency of the granulation process. There are two main types of extruders used in waste plastic recycling granulation: twin-screw extruders and single-screw extruders. Each type has its own advantages and is suitable for different types of waste plastics, as detailed in Section 3.
During extrusion granulation, several key process parameters need to be precisely controlled:
- Temperature: The temperature of the extruder barrel and die is critical for melting the plastic and ensuring good mixing and homogenization. Different types of plastics have different melting points, and the barrel temperature is typically set 10-30°C above the melting point of the plastic to ensure complete melting. For example, the barrel temperature for PP is usually 170-220°C, while for PET it is 260-280°C. Excessively high temperatures can cause thermal degradation of the plastic, leading to a reduction in the mechanical properties of the recycled granules, while excessively low temperatures can result in incomplete melting and poor mixing.
- Shear Rate: The shear rate is determined by the screw speed and the screw design. A suitable shear rate helps to homogenize the molten plastic, disperse any remaining contaminants, and improve the plasticity of the granules. However, excessively high shear rates can cause mechanical degradation of the plastic molecular structure, leading to reduced performance.
- Screw Speed: The screw speed affects the throughput, melting efficiency, and mixing quality. Higher screw speeds can increase the throughput but may reduce the melting and mixing efficiency, while lower screw speeds can improve the mixing quality but reduce the throughput. The optimal screw speed depends on the type of plastic, the extruder type, and the desired granule quality.
- Extrusion Pressure: The extrusion pressure is determined by the die design, screw speed, and material viscosity. Stable extrusion pressure ensures uniform strand formation and consistent granule size. Excessively high pressure can cause die blockage, while excessively low pressure can result in uneven strands.
2.6 Cooling and Cutting
After extrusion through the die, the continuous plastic strands are cooled to solidify them. Cooling can be done using air cooling or water cooling. Water cooling is more efficient and is widely used in large-scale granulation operations, involving passing the strands through a water tank or water spray to quickly cool them to room temperature. Air cooling is suitable for small-scale operations or for plastics that are sensitive to water (such as some engineering plastics).
Once the strands are cooled and solidified, they are cut into uniform granules using a pelletizer. The pelletizer is typically installed at the exit of the cooling system and can be adjusted to control the length of the granules (usually between 2mm and 5mm). Common types of pelletizers include strand pelletizers, water ring pelletizers, and underwater pelletizers. Strand pelletizers are the most widely used type for waste plastic recycling granulation, as they are simple in structure, easy to operate, and suitable for most types of plastics.
2.7 Screening and Packaging
After cutting, the recycled granules are screened using a vibrating screen to remove any oversized or undersized granules, ensuring uniform particle size. The screened granules are then dried again (if necessary) to remove any moisture absorbed during cooling, then packaged into bags or bulk containers for storage and transportation.
Packaging is an important step to prevent contamination and moisture absorption of the recycled granules. The packaging materials should be moisture-proof and clean, and the granules should be stored in a dry, ventilated, and clean warehouse to maintain their quality.
3. Extruder Selection for Waste Plastic Recycling Granulation
As mentioned earlier, the extruder is the core equipment in the waste plastic recycling granulation process. The selection of the right extruder depends on the type of waste plastic, the desired granule quality, the production volume, and the budget. There are two main types of extruders used in waste plastic recycling granulation: twin-screw extruders and single-screw extruders. Each type has its own unique advantages and is suitable for different applications.
3.1 Twin-screw Extruders for Recycling Granulation
Twin-screw extruders are widely used in the recycling granulation of engineering plastics and plastics with high contamination levels, such as ABS, PS, and PET. They consist of two parallel screws that rotate in the same direction (co-rotating) or opposite directions (counter-rotating) within a barrel. Co-rotating twin-screw extruders are more commonly used in plastic recycling due to their superior mixing and conveying capabilities.
3.1.1 Key Advantages of Twin-screw Extruders
- Easy Material Feeding: Twin-screw extruders have a strong conveying capacity, which allows for easy feeding of crushed plastic pieces, even if they are irregular in shape or have a certain amount of contaminants. This reduces the need for pre-processing of the material and improves production efficiency.
- Short Material Residence Time: The residence time of the material in the twin-screw extruder is short (typically 1-5 minutes) compared to single-screw extruders. This helps to avoid thermal degradation of the plastic, especially for heat-sensitive plastics such as PET and ABS, which can degrade easily when exposed to high temperatures for a long time. Short residence time also reduces energy consumption and improves production efficiency.
- Excellent Venting Effect: Twin-screw extruders are equipped with venting ports that allow for the removal of moisture, volatile gases, and air from the molten plastic. The meshing part of the screws provides effective mixing, and the self-cleaning function of the venting section ensures that the material can achieve complete surface renewal, allowing for efficient removal of volatile substances. This helps to improve the quality of the recycled granules by reducing the number of bubbles and defects.
- Superior Mixing and Plasticizing Effect: The co-rotating twin-screw extruders have strong shear and mixing capabilities, which can effectively homogenize the molten plastic, disperse contaminants, and mix additives (such as stabilizers, antioxidants, and colorants) uniformly. This ensures that the recycled granules have consistent properties and good processability.
- Low Specific Power Consumption: Despite their high performance, twin-screw extruders have low specific power consumption (power consumption per unit output), making them more energy-efficient compared to single-screw extruders for certain applications. This helps to reduce operating costs for recycling enterprises.
- High Volume Power: Twin-screw extruders have a high volume power (power per unit volume of the barrel), which means they can process a large amount of material in a small space. This makes them suitable for large-scale production operations with limited space.
3.1.2 Suitable Applications for Twin-screw Extruders
Twin-screw extruders are particularly suitable for the recycling granulation of the following plastics:
- ABS: A high-performance plastic that is widely used in electronic products, auto parts, and toys. ABS is sensitive to heat and requires short residence time and good mixing, making twin-screw extruders the ideal choice.
- PS: Both rigid and foam PS can be recycled using twin-screw extruders. The superior mixing capabilities of twin-screw extruders help to disperse any remaining foam cells and contaminants, ensuring good granule quality.
- PET: PET is highly sensitive to moisture and heat, and requires precise temperature control and short residence time. Twin-screw extruders with good venting and temperature control capabilities are suitable for PET recycling granulation.
- Engineering Plastics: Other engineering plastics such as PC (Polycarbonate), PA (Polyamide), and POM (Polyoxymethylene) can also be recycled using twin-screw extruders, thanks to their superior mixing and plasticizing capabilities.
3.2 Single-screw Extruders for Recycling Granulation
Single-screw extruders are simpler in structure, lower in cost, and easier to maintain compared to twin-screw extruders. They consist of a single screw that rotates within a barrel, conveying and melting the material through friction and shear between the screw and the barrel. Single-screw extruders are widely used in the recycling granulation of general-purpose plastics such as PP, PE, and LDPE.
3.2.1 Key Advantages of Single-screw Extruders
- Short Screw Length and Residence Time: Single-screw extruders typically have a shorter screw length compared to twin-screw extruders, resulting in shorter material residence time. This helps to avoid thermal degradation of the plastic, especially for soft plastics such as PE and LDPE, which have lower melting points and are prone to degradation.
- Cost-Effective: Waste plastic recycling often involves materials with high levels of contaminants, which can cause significant wear and tear on the extruder screw and barrel. Single-screw extruders are simpler in structure and use less expensive materials, making them more cost-effective to replace and maintain compared to twin-screw extruders. This is particularly important for small and medium-sized recycling enterprises with limited budgets.
- Suitable for Soft Plastics: The material conveying efficiency of single-screw extruders depends on the friction performance of the solid material and the viscosity of the melt. Soft plastics such as PP, PE, and LDPE have good friction performance and low melt viscosity, making them ideal for processing with single-screw extruders. These plastics can be conveyed and melted efficiently, ensuring good granule quality.
- Simple Operation and Maintenance: Single-screw extruders have a simple structure, with fewer moving parts, making them easy to operate and maintain. This reduces the need for skilled operators and lowers maintenance costs, which is beneficial for small-scale recycling operations.
3.2.2 Suitable Applications for Single-screw Extruders
Single-screw extruders are particularly suitable for the recycling granulation of the following plastics:
- PP (Polypropylene): PP is a soft plastic with good friction performance and processability, making it ideal for processing with single-screw extruders. Recycled PP granules produced using single-screw extruders have good mechanical properties and can be used in a wide range of applications.
- PE (Polyethylene): Both LDPE and HDPE are suitable for processing with single-screw extruders. LDPE, in particular, is a soft plastic with low melt viscosity, which can be conveyed and melted efficiently by single-screw extruders. Recycled PE granules are widely used in the production of plastic films and pipes.
- LDPE (Low-Density Polyethylene): LDPE is commonly used in plastic films and bags, which are easy to crush and process. Single-screw extruders are ideal for LDPE recycling granulation, as they can handle the soft material efficiently and cost-effectively.
3.3 Key Factors for Extruder Selection
When selecting an extruder for waste plastic recycling granulation, the following key factors should be considered:
- Type of Waste Plastic: As discussed earlier, twin-screw extruders are suitable for engineering plastics (ABS, PS, PET) and plastics with high contamination levels, while single-screw extruders are suitable for general-purpose plastics (PP, PE, LDPE).
- Production Volume: For large-scale production (more than 500kg/h), twin-screw extruders are more suitable due to their high throughput and efficiency. For small-scale production (less than 200kg/h), single-screw extruders are more cost-effective and practical.
- Granule Quality Requirements: If high-quality recycled granules with uniform properties and low contamination are required (such as for automotive parts and electronic products), twin-screw extruders are the better choice due to their superior mixing and plasticizing capabilities. For general-purpose applications (such as plastic films and low-grade injection-molded products), single-screw extruders can meet the requirements at a lower cost.
- Budget: Twin-screw extruders are more expensive than single-screw extruders, both in terms of initial investment and maintenance costs. Therefore, enterprises with limited budgets may prefer single-screw extruders for general-purpose plastic recycling.
- Energy Consumption: For large-scale production, energy consumption is an important consideration. Twin-screw extruders have lower specific power consumption, making them more energy-efficient for high-volume operations. Single-screw extruders may be more energy-efficient for small-scale operations due to their simpler structure.
4. Zhuoyue Extruder Series for Waste Plastic Recycling Granulation
Zhuoyue offers a comprehensive range of extruders specifically designed for waste plastic recycling granulation, including twin-screw extruders and single-screw extruders. The extruder series are tailored to meet the specific needs of different types of waste plastics, production volumes, and granule quality requirements, combining high performance, efficiency, energy-saving, and cost-effectiveness. The main extruder series include ZTE series and HTE series, each with unique features and advantages to suit different application scenarios.
4.1 Core Technical Features of Zhuoyue Extruders
All Zhuoyue extruders for waste plastic recycling granulation share a set of core technical features that make them ideal for the harsh conditions of plastic recycling, such as high contamination levels, irregular material shapes, and varying material properties:
- Robust Construction: Zhuoyue extruders are built with high-quality materials (such as alloy steel for screws and barrels) to withstand the wear and tear caused by contaminants in waste plastics. The screws and barrels are treated with special surface treatments (such as nitriding and hard chrome plating) to improve their wear resistance and service life.
- Precise Temperature Control: The extruders are equipped with advanced temperature control systems, including heating zones and cooling zones, to ensure precise control of the barrel and die temperature. This helps to avoid thermal degradation of the plastic and ensure complete melting and mixing.
- Efficient Conveying and Mixing: The screw designs are optimized for waste plastic recycling, with enhanced conveying capacity and mixing capabilities. Twin-screw extruders feature co-rotating screws with optimized flight profiles to ensure superior mixing and homogenization, while single-screw extruders have specially designed screws to improve conveying efficiency for soft plastics.
- Excellent Venting Performance: Twin-screw extruders are equipped with multiple venting ports to remove moisture, volatile gases, and air from the molten plastic, ensuring high-quality granules with minimal defects. The self-cleaning function of the venting section ensures efficient venting even with contaminated materials.
- Energy-Saving Design: Zhuoyue extruders adopt energy-saving technologies such as variable frequency drives (VFD) and optimized motor configurations to reduce energy consumption. This helps to lower operating costs for recycling enterprises.
- Easy Operation and Maintenance: The extruders are designed with user-friendly interfaces and simple structures, making them easy to operate and maintain. The screws and barrels can be easily disassembled for cleaning and replacement, reducing downtime.
- Customizable Configurations: Zhuoyue extruders can be customized with different screw lengths, diameters, and configurations to meet the specific needs of different types of waste plastics and production volumes. For example, extruders for PET recycling can be equipped with special drying systems and venting ports to ensure complete moisture removal.
4.2 ZTE Series Extruders
The ZTE series is Zhuoyue’s cost-effective extruder series, designed for small and medium-sized recycling enterprises and general-purpose waste plastic recycling granulation. This series offers excellent cost-performance ratio, with parameters designed to suit most common waste plastics, including PP, PE, LDPE, and general-purpose ABS and PS. The ZTE series includes both single-screw and twin-screw extruders, providing flexible options for different applications.
4.2.1 Key Features of ZTE Series Extruders
- Excellent Cost-Performance Ratio: The ZTE series is designed to provide reliable performance at a competitive price, making it the ideal choice for enterprises with limited budgets or small-scale production needs. The initial investment and maintenance costs are significantly lower than high-end extruders, while still meeting the basic requirements of waste plastic recycling granulation.
- Versatile Parameter Design: The parameters of the ZTE series are designed to suit most common waste plastics, including PP, PE, LDPE, ABS, and PS. This versatility allows enterprises to process multiple types of waste plastics with a single extruder, improving production flexibility and reducing equipment investment.
- Reliable Operation: The ZTE series adopts a reliable standard transmission system and simple structure, ensuring stable operation even in harsh recycling environments. The screws and barrels are designed to handle contaminants in waste plastics, reducing the risk of equipment failure.
- Low Maintenance Costs: The simple structure of the ZTE series makes it easy to maintain, with fewer moving parts and lower maintenance requirements. The screws and barrels can be easily replaced when worn, reducing downtime and maintenance costs.
- Suitable for Small to Medium-Scale Production: The ZTE series is available in a range of sizes, with throughputs ranging from 50kg/h to 500kg/h, making it suitable for small to medium-scale recycling operations.
4.2.2 ZTE Series Model Parameters
The ZTE series includes both single-screw and twin-screw extruders, with parameters tailored to different types of waste plastics. The following table details the parameters of the ZTE series twin-screw extruders, suitable for ABS, PS, and PET recycling granulation:
| Model | Specific torque（N.m/Cm³） | Main motor power（Kw） | Output speed（rpm） | Slot depth ratio D0/Di | Suitable Plastics |
|---|---|---|---|---|---|
| 25 | 6 | 7.5 | 600 | 1.55 | PS, Small-scale ABS |
| 35 | 6 | 18.5 | 600 | 1.55 | PS, ABS, LDPE |
| 50 | 6 | 55 | 600 | 1.55/1.68 | ABS, PS, PET (Small-scale) |
| 65 | 6 | 110 | 600 | 1.55/1.68 | ABS, PS, PET |
| 75 | 6 | 160 | 600 | 1.55/1.68 | ABS, PS, PET, PP |
| 95 | 6 | 300 | 600 | 1.55/1.68 | ABS, PS, PET, PP, PE |
The ZTE series single-screw extruders are mainly used for PP, PE, and LDPE recycling granulation, with parameters optimized for soft plastics. The screws are designed with enhanced conveying capacity to handle the irregular shapes of crushed plastic films and bottles, ensuring efficient production.
4.2.3 Application Scenarios for ZTE Series
The ZTE series is ideal for the following application scenarios:
- Small and medium-sized recycling enterprises with limited budgets.
- General-purpose waste plastic recycling, including PP, PE, LDPE, ABS, and PS.
- Production of general-purpose recycled granules for plastic films, low-grade injection-molded products, and construction components.
- Enterprises new to plastic recycling, thanks to the easy operation and low maintenance requirements of the ZTE series.
4.3 HTE Series Extruders
The HTE series is Zhuoyue’s mid-range extruder series, designed to bridge the gap between cost-effective extruders (such as ZTE series) and high-end extruders. This series combines high performance with high cost-effectiveness, delivering higher output while reducing energy consumption. The HTE series includes both twin-screw and single-screw extruders, suitable for medium to large-scale waste plastic recycling granulation.
4.3.1 Key Features of HTE Series Extruders
- Balanced Performance and Cost-Effectiveness: The HTE series offers higher performance than the ZTE series, including better mixing capabilities, higher throughput, and more precise temperature control, while maintaining a competitive price. This makes it suitable for enterprises that require higher granule quality but do not want to invest in high-end extruders.
- Energy-Saving and High Output: The HTE series is optimized for energy efficiency, with advanced motor configurations and variable frequency drives (VFD) to reduce energy consumption. At the same time, the extruders have higher throughput, allowing for medium to large-scale production (500kg/h to 1000kg/h) with lower energy costs.
- Reasonable Torque and Power Configuration: The HTE series has a reasonable torque and power configuration, ensuring stable and efficient production even when processing plastics with high contamination levels or varying properties. The twin-screw extruders have higher torque density, making them suitable for processing engineering plastics such as ABS and PET, while the single-screw extruders are optimized for soft plastics such as PP and PE.
- Dual-Speed Options for Partial Models: Some models of the HTE series are equipped with dual-speed options, allowing for flexible adjustment of the screw speed to suit different types of plastics and production requirements. This expands the application range of the extruders, making them suitable for multiple plastic types.
- Enhanced Wear Resistance: The screws and barrels of the HTE series are made of high-quality alloy steel and treated with advanced surface treatments to improve their wear resistance, ensuring a long service life even in harsh recycling environments.
- Advanced Control System: The HTE series is equipped with advanced PLC control systems, allowing for automatic control of temperature, screw speed, extrusion pressure, and other key parameters. This improves the stability and consistency of the granulation process, ensuring uniform granule quality.
4.3.2 HTE Series Model Parameters
The HTE series twin-screw extruders are suitable for ABS, PS, PET, PP, PE, and LDPE recycling granulation, with parameters optimized for high performance and efficiency. The following table details the specific parameters:
| Model | Specific torque（N.m/Cm³） | Main motor power（Kw） | Output speed（rpm） | Slot depth ratio D0/Di | Suitable Plastics | Throughput (kg/h) |
|---|---|---|---|---|---|---|
| 25 | 9 | 11 | 600 | 1.55 | PS, ABS, LDPE | 50-100 |
| 35 | 9 | 30 | 600 | 1.55 | PS, ABS, PE, LDPE | 100-200 |
| 35 | 9 | 45 | 1000 | 1.55 | PS, ABS, PE, LDPE | 200-300 |
| 50 | 9 | 75 | 600 | 1.55/1.68 | ABS, PS, PET, PP | 300-500 |
| 50 | 9 | 110 | 900 | 1.55/1.68 | ABS, PS, PET, PP | 500-700 |
| 65 | 9 | 160 | 600 | 1.55/1.68 | ABS, PS, PET, PP, PE | 700-900 |
| 65 | 9 | 220 | 900 | 1.55/1.68 | ABS, PS, PET, PP, PE | 900-1200 |
| 75 | 9 | 250 | 600 | 1.55/1.68 | ABS, PS, PET, PP, PE, LDPE | 1200-1500 |
| 75 | 9 | 315 | 900 | 1.55/1.68 | ABS, PS, PET, PP, PE, LDPE | 1500-1800 |
| 95 | 9 | 400 | 600 | 1.55/1.68 | All common waste plastics | 1800-2200 |
The HTE series single-screw extruders are optimized for PP, PE, and LDPE recycling granulation, with higher throughput and better energy efficiency compared to the ZTE series. They are suitable for medium to large-scale production of recycled granules for plastic films, pipes, and injection-molded products.
4.3.3 Application Scenarios for HTE Series
The HTE series is ideal for the following application scenarios:
- Medium to large-scale recycling enterprises with higher granule quality requirements.
- Recycling of multiple types of waste plastics, including PP, PE, LDPE, ABS, PS, and PET.
- Production of high-quality recycled granules for automotive parts, electronic product accessories, and high-grade injection-molded products.
- Enterprises that focus on energy efficiency and cost reduction, thanks to the energy-saving design of the HTE series.
4.4 Customized Solutions from Zhuoyue
In addition to the standard ZTE and HTE series, Zhuoyue also provides customized extruder solutions for special waste plastic recycling needs. For example:
- Customized extruders for high-contamination waste plastics, equipped with enhanced filtering systems to remove contaminants.
- Extruders for heat-sensitive plastics such as PET and PC, equipped with special drying systems and low-shear screws to avoid thermal degradation.
- Complete recycling granulation production lines, including crushers, dryers, extruders, pelletizers, and screening equipment, to provide a one-stop solution for enterprises.
Zhuoyue’s professional R&D team works closely with customers to understand their specific needs and provide tailored solutions that meet their production requirements and budget.
5. Best Practices for Waste Plastic Recycling Granulation with Zhuoyue Extruders
To ensure the best performance and granule quality when using Zhuoyue extruders for waste plastic recycling granulation, the following best practices are recommended:
5.1 Proper Sorting and Cleaning
Effective sorting and cleaning are essential to reduce the wear and tear on the extruder and ensure high-quality granules. Separate different types of plastics to avoid mixing, and remove non-plastic contaminants (such as metal, paper, and glass) as much as possible. Thoroughly clean the waste plastics to remove oil, grease, and food residues, which can affect the mixing and plasticizing effect.
5.2 Optimal Drying
Ensure that the crushed plastic pieces are properly dried to reduce the moisture content to below 0.5%. For moisture-sensitive plastics such as PET, use high-temperature drying (120-160°C) for a sufficient period to ensure complete moisture removal. This helps to avoid bubbles and defects in the recycled granules.
5.3 Precise Process Parameter Control
Adjust the extruder parameters (such as temperature, screw speed, and extrusion pressure) according to the type of waste plastic. Follow the recommended parameter settings provided by Zhuoyue, and make adjustments based on the actual material properties and granule quality. Avoid excessively high temperatures or shear rates, which can cause plastic degradation.
5.4 Regular Maintenance
Regularly inspect and maintain the extruder to ensure its normal operation. Clean the screws and barrels regularly to remove any accumulated material or contaminants. Check the wear of the screws and barrels, and replace them when necessary. Lubricate the moving parts regularly to reduce friction and extend the service life of the extruder.
5.5 Use of Additives (If Necessary)
For waste plastics with severe degradation or poor performance, consider adding additives such as stabilizers, antioxidants, and plasticizers to improve the quality of the recycled granules. Consult Zhuoyue’s technical team to select the appropriate additives and dosage.
6. Conclusion
Waste plastic recycling granulation is a critical technology for realizing resource circulation and environmental protection, offering significant economic, environmental, and social benefits. The quality and efficiency of the granulation process depend largely on the extruder used, and selecting the right extruder is essential for the success of a plastic recycling enterprise.
Zhuoyue’s ZTE series and HTE series extruders are specifically designed for waste plastic recycling granulation, combining high performance, efficiency, energy-saving, and cost-effectiveness. The ZTE series provides a cost-effective solution for small and medium-sized enterprises and general-purpose plastic recycling, while the HTE series offers balanced performance and cost-effectiveness for medium to large-scale production with higher quality requirements. With robust construction, precise temperature control, superior mixing capabilities, and customizable configurations, Zhuoyue extruders can handle all types of waste plastics, from PP and PE to ABS and PET, delivering high-quality recycled granules for a wide range of applications.
As a leader in extrusion technology, Zhuoyue is committed to providing advanced, reliable, and cost-effective solutions for the plastic recycling industry. With professional R&D, high-quality products, and comprehensive after-sales service, Zhuoyue helps enterprises unlock the full potential of waste plastic recycling, contributing to a more sustainable and environmentally friendly future.