What are you actually buying when you order a "PET recycling line"?
The phrase "PET washing line" describes an integrated chain of machines, not a single machine, and that is the first source of misunderstanding between buyer and Chinese supplier. A typical line starts with baled bottles and ends with clean flakes ready for sale or for feeding an extrusion line. Any quotation that does not list the equipment item by item, with installed power and steel grade per unit, should be treated as incomplete until proven otherwise.
Standard stages of the line
- Bale opener to break compressed bales and feed the line at a steady rate.
- Manual sorting belt to remove PVC, PE, metals and unwanted coloured bottles.
- Label remover to separate BOPP labels and glue before grinding.
- Wet crusher to reduce bottles to flakes of 10–14 mm.
- Float–sink separation tank to split floating PP/PE caps from sinking PET flakes.
- Hot caustic soda washing at 85–95 °C to dissolve glue, oils and organic residue.
- High-speed friction washer followed by rinsing to remove alkaline traces.
- Centrifugal dryer, then hot-air dryer, followed by a storage silo and bagging station.
How do you calculate the capacity you need in kg/h?
Start from the market, not from the machine. Establish how many tonnes of bales are available each month in your region at a stable price, then divide by real operating hours. The practical formula: required capacity = (target tonnes per month × 1000) ÷ (working days × shift hours × utilisation factor). A realistic utilisation factor for washing lines is between 0.75 and 0.85, because of stoppages, tank water changes and daily cleaning.
Worked example: to produce 300 tonnes per year on a single shift (8 hours, 26 working days per month) you need 300000 ÷ (12 × 26 × 8 × 0.8) ≈ 150 kg/h of finished flakes. One caution is decisive here: suppliers usually quote input capacity measured in bales, while losses between bale and final flake run from 15% to 25% (labels, caps, moisture, contamination). Always ask for capacity measured at the dryer outlet, not at the bale opener inlet.
| Item | 500 kg/h | 1000 kg/h | 2000 kg/h |
|---|---|---|---|
| Approximate installed power | 120 kW | 200 kW | 350 kW |
| Water consumption with recirculation | 1.5 m³/h | 2.5 m³/h | 4 m³/h |
| Floor area required | 300 m² | 500 m² | 800 m² |
| Operators per shift | 6–8 | 10–12 | 16–20 |
The flake specifications that set your selling price
Flakes are not a single product; the price gap between an industrial-grade flake and one suitable for re-extrusion can exceed a third. The specifications a serious buyer will ask about:
- Moisture below 1% at bagging.
- PVC content below 50 ppm and PE/PP content below 100 ppm.
- Intrinsic viscosity (IV) of at least 0.72 dl/g to preserve processability.
- Dust and fines below 1%, with flakes free of fibres and glue.
- Consistent flake size within a narrow range, to avoid screw feeding problems downstream.
The golden rule: flake quality is made at the manual sorting stage before grinding, not in the washing tanks after it. Every gram of PVC that enters the crusher will never be removed by any washer, and will reappear later as burnt specks in the final product.
Common mistakes when importing a recycling line from China
- Skipping the wash-water treatment plant: the line runs without it, but the local environmental authority may shut the factory down within weeks.
- Accepting a low steel grade on parts in contact with hot caustic; require 304 as a minimum and 316 in the hot washing tanks.
- Relying on catalogue nominal capacity without a factory acceptance test (FAT) on bales from the buyer's own country, since bale cleanliness differs radically between markets.
- Leaving caustic soda, detergents, energy and water out of the feasibility study — usually the second largest operating cost after buying bales.
- Failing to agree in writing on the wear-parts list: crusher blades, filters, belts and pump seals.
Practical checklist before signing the contract
Ask the supplier for three documents before the first payment: a dimensioned process flow diagram, an electrical and water load schedule per unit, and a video-documented test report covering both capacity and quality. Those three documents turn a quotation from a promise into a measurable commitment, and save months of argument after the containers arrive. If you are studying a PET washing and recycling line and need a technical review of the offer, or a shortlist of factories matching your specification, talk to our team for an independent assessment before you decide.