Plastic recycling plays a pivotal role in modern sustainability efforts, aiming to minimise waste and repurpose materials into new products. Among the various stages of the recycling process, ontwatering is crucial, as it removes water from washed plastics, preparing them for further processing.
This article provides an in-depth look at the role, types, and advantages of dewatering machines in plastic recycling, offering valuable insights for industry professionals and environmentally conscious readers alike.
Understanding Dewatering Machines
Dewatering machines are specialised equipment designed to extract water from materials. In plastic recycling, their primary function is to remove excess moisture from washed plastics, ensuring they are ready for drying, pelletising, or extrusion. Excess water can compromise efficiency, damage equipment, En affect the quality of recycled plastic.
A typical plastic recycling process includes:
1. Verzamelen & sorteren – Separating plastics by type and quality.
2. Wassen – Removing dirt, labels, and other impurities.
3. Ontwatering – Extracting as much water as possible from cleaned plastic.
4. Drogen – Further reducing moisture for optimal processing.
5. Pelletising/Extrusion – Converting plastic into new products.
Research highlights the significant moisture variability in washed plastics. Some plastics, such as films, may retain up to 30% water, while others can hold as much as 70% moisture before dewatering. The dewatering process aims to reduce this level to between 5-30%, depending on the machine type, ensuring optimal conditions for downstream processing.
Learn more about high-performance dewatering solutions at Energycle.
Types of Dewatering Machines and Their Mechanisms
Several dewatering technologies are used in plastic recycling, each offering unique advantages based on plastic type and operational needs.
1. Centrifugal Dewatering Machines
Centrifugal dewatering machines use high-speed spinning forces to expel water from plastics. They are particularly effective for small plastic flakes and particles, commonly used in plastic film recycling plants.
• Belangrijkste voordelen: High efficiency, rapid moisture reduction.
• Moisture Content Post-Dewatering: Typically 5-30%.
• Usage: Suitable for various plastic types, including PET, HDPE, and PP flakes.
Explore Energycle’s advanced centrifugal dewatering machines.
2. Step Dryers
Step dryers use a multi-stage process to extract water, employing a step-shaped basket screen and rotor. They are particularly effective in recycling thermoplastics like polycarbonate and polypropylene, achieving exceptionally low moisture levels.
• Belangrijkste voordelen: Achieves ultra-low moisture levels (0.4-0.06 wt%), ensuring high-quality recycling.
• Moisture Content Post-Dewatering: As low as 0.06%.
• Usage: Ideal for high-end recycling operations requiring premium-quality output.
Screw presses remove water using mechanical pressure, making them ideal for large-scale plastic recycling plants. They are particularly efficient for plastic films and soft plastics, reducing moisture to as low as 3% in some cases.
• Belangrijkste voordelen: Energy-efficient, handles large volumes.
• Moisture Content Post-Dewatering: 2-10% (depending on model and material).
• Usage: Effective for plastic films, bags, and soft plastics.
Each type of dewatering machine offers distinct advantages, and the best choice depends on moisture content, plastic type, and plant capacity.
Key Benefits of Dewatering Machines in Plastic Recycling
Dewatering machines play a critical role in optimising recycling operations, providing the following advantages:
1. Reducing Weight & Volume
By eliminating excess water, dewatering machines significantly reduce the weight and volume of plastic waste, making storage and transportation more cost-effective.
Example Calculation:
• 1 tonne of plastic waste with 70% moisture weighs 3.33 tonnes.
• After dewatering to 20% moisture, it weighs just 1.25 tonnes.
• This 62% reduction results in lower logistics costs and increased processing efficiency.
2. Preparing for Further Processing
Moisture content must be minimal for efficient extrusion and pelletising. Excess water can cause material defects, such as brittleness, and even damage equipment. Dewatering ensures that plastic is optimally prepared for subsequent processing.
3. Improving the Quality of Recycled Plastic
Higher-quality recycled plastic results from effective dewatering, preventing issues such as cracking, warping, or weakened structural integrity. This is particularly important for industries where precise material standards are required.
4. Cost Savings & Increased Efficiency
By reducing moisture content, less energy is required for subsequent thermal drying, lowering operationele kosten. Additionally, lighter material means lower transport expenses.
Case Study:
• A recycling plant using a WEIMA C.200 press saved €250 per day on transportation and disposal costs.
• The investment paid off within a year, proving the economische voordelen of effective dewatering.
Challenges & Considerations
Despite their effectiveness, dewatering machines may not completely eliminate moisture, necessitating further drying. Moisture levels after dewatering can vary:
• Centrifugal dewatering machines: 5-30% moisture.
• Step dryers: As low as 0.06% moisture.
• Squeezing: 2-10% moisture (depending on design and material processed).
Selecting the right dewatering machine is crucial to maximising efficiency, cost savings, and output quality.
Conclusie
Dewatering machines are indispensable in plastic recycling, enhancing efficiency, quality, and sustainability. By removing water effectively, they help reduce costs, improve product quality, and support a greener future.
For those looking to optimise their plastic recycling process, choosing the right ontwateringsmachine is a strategic investment that can increase profitability and environmental impact.
Discover Energycle’s industry-leading dewatering solutions here.
Comparison Table: Dewatering Machine Types
| Machinetype | Mechanism | Key Benefit | Typical Moisture Post-Dewatering | Common Usage |
|---|---|---|---|---|
| Centrifugal Dewatering | High-speed spinning expels water | Efficient for small particles | 5-30% | Various plastics (PET, HDPE) |
| Step Dryers | Multi-stage water removal | Achieves ultra-low moisture levels | 0.4-0.06% | High-end thermoplastics |
| Squeezing Machine | Mechanical pressure extraction | Handles large volumes, energy-efficient | 2-10% | Plastic films, soft plastics |
By selecting the right dewatering machine, recycling facilities can optimise their operations, cut costs, and contribute to a more sustainable future.
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