PET Recycling Machines Compared: How to Choose the Right Line

PET projects succeed when you design backward from the end market. “A PET recycling machine” can mean anything from a basic wash plant that sells hot-washed flakes to a bottle-to-bottle line that produces pellets for regulated applications.

This guide compares the major PET line configurations and explains which modules matter most for your target product: washed flakes, pellets, or food-contact rPET. It uses Energycle’s PET bottle recycling system as a reference point for typical workflow blocks.

Quick takeaways – Sorting quality drives everything: PVC and metal contamination can ruin batches and increase scrap. – PET wash plants often rely on a hot caustic wash to remove adhesives and label residue, which drives both capex and wastewater load. (Source: APR PET design guidance) – Drying is not optional if you remelt PET; moisture control affects polymer degradation and IV consistency. (Source: CWC PET drying guidance)

What Are You Actually Building? (Flakes Plant vs Pellets Plant)

Use this table to pick the “type” of PET recycling system before you compare equipment quotes.

Target output	Typical buyer goal	What the system must do well	Modules that usually make or break the project
Washed PET flakes	Sell flakes to sheet/fiber/pellet producers	Remove labels/adhesives, PP/PE caps, metals, grit	Sorting, hot wash, sink-float, drying, wastewater handling
rPET pellets	Sell pellets to molders/extruders	Hold stable melt, filter contaminants, control odor/VOCs	Drying, extrusion/degassing, melt filtration, pelletizing + pellet drying
Food-contact rPET (market-specific)	Supply regulated markets	Track input, prove decontamination, control quality tightly	Upstream quality control, decontamination concept, documentation and validation

1. The Front Line: Bale Breaking and Sorting

Before any plastic is cut, it must be singled out and sorted. If you buy bales, start with bale specs and incoming QC because yield and contamination drive your entire cost model.

APR publishes model bale specifications that many buyers use as market acceptance guidelines for post-consumer bales. Use them to align “what you think you’re buying” with what the market calls acceptable. (Source: APR Model Bale Specifications)

Manual vs. Automated Bale Breaking:
- Manual: Suitable for low-capacity lines (<500 kg/h). Labor-intensive but low capital cost.
- De-baler Machine: Essential for high-capacity lines. It uses low-speed shafts to tease apart compressed bottles without shattering them, ensuring a steady feed to the sorters.
Trommel vs. Ballistic Separator:
- Trommel: A large rotating drum that removes small contaminants (rocks, glass) by size. Great for dirty collection streams.
- Ballistic Separator: Uses paddling motion to separate 2D items (labels/films) from 3D items (bottles). Higher precision, recommended for bottle-to-bottle lines.

2. Size Reduction: Crusher Configurations

The heart of the mechanical process. The wrong crusher generates excessive “fines” (dust), which is pure material loss.

Wet Grinding vs. Dry Grinding:
- Dry Grinding: Standard for lower throughputs. High noise and dust generation.
- Wet Grinding: Water is sprayed into the cutting chamber. This cools the blades, reduces dust, and starts rinsing early—useful when you are targeting cleaner flakes.

3. Washing Systems: The Cleanliness Factor

This is the most critical stage for value addition. The difference between “dirty flake” and “hot-washed flake” often determines which buyers will even consider your material.

APR’s PET rigid packaging design guidance describes the PET reclamation process as involving a hot caustic wash that removes adhesives and other label components—useful context for why wash chemistry and water treatment load show up as major line cost drivers. (Source: APR Design Guide — PET Rigid)

System Type	Key Feature	Ideal For	Cost Impact
Cold Wash Only	Uses ambient water, sometimes with detergent.	Lower-end applications where odor/appearance specs are forgiving.	Low Opex, Low Sale Price
Steam / Hot Wash	Uses heated water with chemistry to remove glue, oils, and organics.	Sheet extrusion, bottle-to-bottle, high-end fiber.	High utility cost, High Profit Margin
Sink-Float Tanks	Density separation (PET sinks, PP/PE caps float).	Standard separation for all bottle lines.	Standard

Wash line modules buyers should specify explicitly

Many quotes hide performance assumptions inside vague phrases like “washing system.” Make the supplier spell out the modules and what each is supposed to remove.

Pre-wash / trommel / grit removal: protects downstream equipment and reduces filter load
Friction washer: targets surface contamination and loosens labels
Hot wash reactor (if used): targets adhesives, oils, and organics
Sink-float separation: removes caps/rings (PP/PE floats, PET sinks)
Rinsing and drying: controls moisture, which affects storage and remelting performance
Wastewater treatment interface: defines what your plant must handle (filters, chemistry, sludge)

If you want a dedicated reference layout, Energycle’s PET bottle washing line page shows a typical sequence from size reduction through washing, separation, and drying.

4. Drying: Moisture is the Enemy

PET is hygroscopic. Excess moisture causes hydrolytic degradation during remelting.

Mechanical drying: A centrifugal step removes bulk surface water after washing.
Thermal drying (as needed): Used when you must hit a tighter moisture target for bagging, transport, or pelletizing.

If you pelletize PET, treat drying as a quality control step, not an accessory. A PET recycling guidance document on drying notes that moisture in melted PET can drive hydrolysis and reduce molecular weight, and that PET must be thoroughly dried before melt processing to control IV loss. (Source: CWC PET drying guidance (BP-PET3-05-01))

5. Pelletizing: The Upgrade Step

Converting flakes to pellets opens up more end markets, but it also adds new failure modes: unstable melt pressure, screen-change downtime, and odor/VOC problems if degassing is weak.

Single Screw Extruder:
- Best For: Clean, dry, pre-washed flakes. Lower output, simpler maintenance.
Twin Screw Extruder:
- Best For: Material requiring degassing (ink/moisture removal) and additive mixing. High torque, better mixing, significantly higher price point.
Vacuum Degassing:
- Standard: One vent port.
- High-Performance: Double or triple degassing zones. Essential for removing volatile organic compounds (VOCs) for food-grade compliance.

To compare pelletizing concepts and downstream handling options, you can also reference Energycle’s plastic pelletizer machines category and its guide to pelletizing methods.

Filtration and pellet quality

If you plan to sell pellets, buyers will judge you on consistency: pellet size distribution, gels/black specs, and lot-to-lot stability. Filtration and melt pressure stability are a big part of that.

For example, Gneuss describes the operational risk of screen changes causing pressure spikes or interruptions and outlines filtration concepts aimed at maintaining constant melt flow conditions by controlling screen contamination. (Source: Gneuss melt filtration overview)

Decision Matrix: What Do You Need?

Scenario A: The “Wash Plant”

Goal: Buy baled bottles, sell clean flakes.
Key investment: Sorting + hot washing. Size reduction is important, but cleanliness is what determines sale price.
What to spec: Bale quality, washing chemistry, separation efficiency, and drying capacity.

Scenario B: The “In-House” Recycler

Goal: Recycle factory rejects (preforms/bottles) back into production.
Key Investment: High-quality Single Shaft Shredder and a dust-free Granulator. No washing needed (material is clean).
Priority: Zero contamination.

Scenario C: The Full-Scope Processor

Goal: Dirty bottles to food-grade pellets (rPET).
Key Investment: Solid State Polycondensation (SSP) capabilities (often downstream of pelletizing) and intense filtration.
Requirement: FDA/EFSA compliance tracking.

For examples of bottle-to-bottle system concepts, manufacturers describe integrated decontamination and IV management approaches. For instance, EREMA’s VACUREMA concept describes defined vacuum treatment time at higher temperature and melting under vacuum, plus filtration features. (Source: EREMA VACUREMA details)

Starlinger’s recoSTAR PET description also highlights melt filtration and low VOCs as part of its rPET pellet output claims. (Source: Starlinger recoSTAR PET overview)

Common Failure Modes (And How to Avoid Them)

These issues show up in real procurement projects:

1) You buy the wash line before you define bale quality. Result: you pay to process contamination you can’t sell. 2) PVC control is vague. Result: frequent scrap events and customer rejections. 3) Hot wash and water treatment are undersized. Result: poor glue removal and unstable flake quality. 4) Drying is treated as a conveyor. Result: hydrolysis risk and IV drift in pelletizing. 5) Filtration is priced like an accessory. Result: downtime and unstable pellet quality.

FAQ (Real Procurement Questions)

What should I send suppliers so I get quotes that are actually comparable?

Send a one-page input spec and a one-page output spec. Input should include bale source, expected contamination (PVC/other polymers, metals, labels/paper, fines), moisture condition, and target throughput. Output should define whether you sell cold-washed flake, hot-washed flake, or pellets, plus the acceptance tests your buyers use (visual contamination limits, moisture target, IV target if pelletizing). Also ask each supplier to list modules line-by-line (sorting, washing, separation, drying, filtration, pelletizing) and to define yield assumptions. APR bale specifications are a good reference point for aligning on incoming material definitions. (Source: APR Model Bale Specifications)

Do I really need hot washing for post-consumer PET bales?

Often yes if you sell higher-grade flakes or plan to pelletize, because adhesives and label residue can limit cleanliness. APR’s PET rigid design guidance describes hot caustic washing as part of the PET reclamation process for removing adhesives and label components, which is why many higher-spec lines include it. Still, the right answer depends on your bale stream and buyer spec. If your market accepts lower cleanliness, a simpler wash may work—especially with better sorting and separation. Decide with a trial tied to buyer acceptance tests. (Source: APR Design Guide — PET Rigid)

How do I decide between selling flakes vs making rPET pellets?

Start with customers, not equipment. Flake plants win when they can consistently meet a buyer’s cleanliness and moisture targets at low operating cost. Pellet plants win when customers pay for consistency and you can hold stable melt pressure, filtration, and odor control. Pelletizing also adds drying and hydrolysis risk: a PET drying guidance document notes that moisture in melted PET can hydrolyze the polymer and reduce molecular weight, affecting IV. If you can’t control drying and filtration, pellets can be harder to sell than flakes. Build your business case around delivered quality and yield, not just price per ton. (Source: CWC PET drying guidance)

What’s the easiest way to de-risk PVC contamination in a PET bottle line?

Define a measurable incoming and outgoing spec, then design the sorting and QC around it. That includes bale inspection routines, automated sorting where appropriate, and checkpoints that catch PVC early enough to avoid contaminating your wash system. Also plan for “what happens when PVC slips through” (reject stream handling and operator response). Use common identification and labeling standards to align materials language across your team and suppliers; ASTM D7611 is widely referenced for resin identification coding. Most importantly, ask suppliers to explain how they detect and remove PVC and how they prove performance during acceptance testing. (Source: ASTM D7611 overview)

If I plan to pelletize, what modules matter most besides the extruder?

Drying, degassing, filtration, and pellet handling. Drying and degassing protect polymer quality and help stabilize the melt. Filtration and melt pressure stability determine pellet consistency and downtime frequency. Pelletizing method and pellet drying determine fines, moisture, and handling quality. Plastics Technology notes that underwater pelletizing success depends on proper specification of extruders, pumps, filters, water systems, and dryers working together—use that mindset even if you choose a strand system. Ask suppliers to show pellet quality and downtime assumptions at your target throughput, not only equipment descriptions. (Source: Plastics Technology — The Path to Pellet Perfection)

If I target food-contact rPET, what’s the first compliance document I should read?

For U.S. projects, start with FDA’s guidance on chemistry considerations for using recycled plastics in food packaging and align your validation plan with your end-market requirements. “Food-contact” is not only a machine choice; it includes input control, process control, documentation, and testing. Use the guidance to structure questions for your technology provider and to define what data you need from trials and ongoing production. Also confirm what your customers and regulators accept in your market (U.S. vs EU requirements differ). (Source: FDA recycled plastics guidance PDF)

Summary

There is no one-size-fits-all PET recycling system. Choose the line configuration based on your target output (flakes vs pellets vs regulated markets), then specify each module so the quote reflects your real feedstock and your buyer’s acceptance tests.

Sustainable Solutions for a Circular World