PET Bottle Washing Line: From Baled Bottles to Market-Ready Flake
Post-consumer PET bottles arrive as dense bales mixed with paper labels, PP caps, glue, sand and organic residue. A purpose-built PET bottle washing line strips that contamination in a fixed sequence and hands your granulator or end buyer a flake they will actually pay for. This guide walks through the process stage by stage, with the reference capacities LVKESORT publishes for its WL series.
Why PET Bottles Need a Dedicated Line
PET is one of the easiest polymers to recycle and one of the easiest to get wrong. The bottle itself is clean value; everything attached to it is not. A typical bale of post-consumer bottles carries:
- Paper and film labels held on by glue
- PP caps, rings and sleeves
- Sand, grit and organic residue from collection
- Traces of metal from caps and contamination
If labels are crushed together with the bottles, glue smears across the flake surface and ends up in the wash bath, contaminating every kilogram downstream. That is why a PET line is designed around a fixed sequence rather than a single wash tank: each stage removes one class of contamination before it can spread.
The Six Stages of a PET Bottle Washing Line
LVKESORT PET lines follow a process sequence that has been refined over decades of bottle-to-flake projects:
Process Sequence
- De-baling — bales are opened and metered at a steady rate so downstream stages never starve or flood.
- De-labeling — labels and sleeves are separated before crushing, which keeps glue out of the wash bath and off the flake.
- Crushing — a PS-series crusher reduces whole bottles to flake size, opening every surface for washing.
- Hot washing — heated wash liquor with dosing removes glue and organic residue that cold water cannot lift.
- Density separation — caps, rings and other PP/PE fractions float off while PET heavies sink.
- Dewatering and drying — flakes are dewatered and dried to the moisture your granulator or end user accepts.
The order matters most at stages two and three. De-labeling before crushing is what keeps glue out of the wash bath; crushing before hot washing is what gives the detergent access to every surface. Lines that skip the de-labeling stage fight glue contamination for the rest of the process.
Reference Line Configurations
The published WL series covers four reference configurations. PET projects normally sit on WL-1000 and above, so the hot-wash stage has enough dwell time at commercial throughput:
| Model | Capacity (kg/h) | Water use (t/h) | Total power (kW) | Outlet moisture | Typical feed |
|---|---|---|---|---|---|
| WL-500 | 500-800 | 3-5 | 80-120 | ≤2% | Small bottle collection |
| WL-1000 | 1,000-1,500 | 5-8 | 120-180 | ≤2% | Municipal bottle fractions |
| WL-2000 | 2,000-3,000 | 8-12 | 180-250 | ≤2% | Regional bottle recovery |
| WL-5000 | 3,000-5,000 | 12-20 | 250-300 | ≤2% | Large bottle-to-flake plants |
Two reading notes on this table. First, outlet moisture of 2% or less is the published target across the series, which is what most flake buyers expect at delivery. Second, flake quality targets such as residual moisture and label content are confirmed after a wash trial on your bales — input contamination varies by region and collection scheme, and the trial is what turns a reference line into your line.
The Three Machines That Decide Flake Quality
Inside the line, label removal, friction washing and dewatering are the three stages that decide whether flake passes specification:
- Label removal — separating labels and sleeves before crushing is the cheapest contamination control in the whole line, because every gram of glue kept out of the bath is a gram that never reaches the flake.
- Friction washing — high-speed rubbing between flake particles scrubs glue and residue off the surface. LVKESORT friction washers run at 500-800 rpm with capacities from 300-500 kg/h (FW-500) up to 1,500-2,000 kg/h (FW-1200). See the friction washer specifications.
- Dewatering — centrifugal dewatering machines in the VD series reach a dewatering rate of 95% or more before final thermal drying, which directly cuts the energy the drying stage needs.
The PS-series crusher is the fourth machine to size carefully, because flake geometry affects how well every later stage works. Full machine links are listed on the PET bottle washing line product page.
Water Management: Consumption and Closed-Loop Operation
Water is the second operating cost of a PET line after power. The published series ranges from 3-5 t/h on the WL-500 to 12-20 t/h on the WL-5000. Those figures describe the closed-loop water system including treatment: wash water circulates, treatment removes the fines, glue and organics it picks up, and only the treatment side consumes fresh make-up water.
When you compare lines between suppliers, always ask whether quoted water figures assume a closed loop or once-through use. A line that looks cheaper on paper can be expensive at the water bill and at the effluent discharge point.
What Decides Flake Quality (and Price)
Flake buyers grade material on a short list of parameters, and every one of them traces back to a stage in the line:
- Label and glue content — controlled by de-labeling and hot-wash chemistry.
- Residual moisture — controlled by the dewatering and drying stages; the published WL target is 2% or less.
- Wash temperature and dwell time — set during the material trial to match your glue and residue profile.
- Water quality — maintained by the closed-loop treatment system.
Colour sorting is a separate discipline: the washing line removes contamination, while colour and polymer sorting are configured to your target output. A line can produce clean mixed-colour flake or feed a downstream sorting stage for food-grade applications — the washing stage itself does not change.
Frequently Asked Questions
How much water does a PET bottle washing line use?
The published WL series ranges from 3-5 t/h on the WL-500 to 12-20 t/h on the WL-5000. The line runs a closed-loop water system including treatment, so circulating water is reused and only the treatment side needs fresh make-up water.
Do I need a de-labeling stage before crushing?
For bottle-to-flake quality, yes. Removing labels and sleeves before the bottles are crushed keeps glue out of the wash water and off the flake surface.
Can the line handle coloured bottles?
Yes. The washing line removes contamination such as labels, caps, glue and residue. Colour and polymer sorting are a separate stage, configured according to your target flake output.
What decides PET flake quality?
Label and glue removal, wash temperature and dwell time, water quality, and the drying stage. Targets such as residual moisture and label content are confirmed after a wash trial on your actual bales.
Planning a Bottle-to-Flake Project?
Send bale photos and your target flake specification. LVKESORT's engineering team will size the line and confirm quality targets with a wash trial on your material.