Plastic polymer landscape - technical summary
This table covers six plastic polymer types (PE, PP, PS, MLP, PET, PVC) with their resin identification codes, pyrolysis suitability rating, the type of output each produces, and the reactor handling action required for each.
| Polymer Type | Resin Code | Pyrolysis Suitability | Main Output Type | Reactor Action Required |
| PE (HDPE/LDPE) | 2 & 4 | Premium | High-Yield Liquid Oil | Maximize feed ratio for best oil density. |
| PP | 5 | Premium | High-Yield Liquid Oil | Mix freely with PE to optimize fluid viscosity. |
| PS | 6 | Good | Aromatic Rich Liquid | Monitor burner settings to manage soot. |
| MLP (Multi-Layer) | 7 | Moderate | Oil + Aluminum Residue | Run specialized char screening to recover aluminum flakes. |
| PET | 1 | Poor | Carbon Dioxide & Acid | Sort out via Optical Sorting down to <5\%. |
| PVC | 3 | Hazardous | Hydrochloric Acid Gas | Must be eliminated (<0.1%) to prevent plant damage. |
Beyond definitions
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How to read this table
- Resin codes are the triangular recycling symbols printed on plastic products (1–7); use these to identify polymer type during sorting
- Suitability ratings: Premium = high yield, clean oil; Good = high yield, manageable issues; Moderate = lower yield, extra handling needed; Poor = low yield, avoid above trace levels; Hazardous = must be eliminated entirely
- "Reactor Action Required" describes the specific operational step needed for that polymer type — follow these when designing your sorting and char management processes
About this table
Not all plastic is equal as pyrolysis feedstock. The six major polymer types that appear in municipal and industrial plastic waste each behave differently inside the reactor — producing different outputs, creating different operating challenges, and requiring different pre-processing or handling actions. Knowing the polymer landscape is the foundation of feedstock procurement and quality control.
Polyethylene (PE) — resin codes 2 (HDPE) and 4 (LDPE) — and Polypropylene (PP) — resin code 5 — are the two premium feedstocks. Both produce high liquid oil yields with good fuel properties, and they can be mixed freely in the reactor. PE produces a paraffinic oil close to diesel; PP adds a higher gasoline-range fraction. Together they are the backbone of Indian pyrolysis plant economics. Polystyrene (PS) — resin code 6 — also rates as good, with very high oil yield but producing aromatic-rich oil that needs burner management to avoid soot buildup.
Multi-Layer Packaging (MLP) — resin code 7 — is moderate in suitability. It produces oil mixed with aluminum residue from the laminate layers, and requires char screening after each batch to recover aluminum flakes and prevent buildup in the char discharge system. PET — resin code 1, the clear water bottle — is rated poor: it produces carbon dioxide and acidic compounds rather than useful hydrocarbons, and needs to be sorted out to below 5% of the feed to avoid yield and quality losses.
PVC — resin code 3 — is the critical hazard. When heated, PVC releases hydrochloric acid gas, which corrodes reactor walls, heat exchangers, and condensers at concentrations above 0.1%. A single contaminated batch can cause equipment damage costing more than the plant's monthly revenue. PVC must be eliminated from the feedstock stream through optical sorting, manual picking, or density separation before it enters the reactor. This is the single most important quality control rule in plastic pyrolysis.
Key insights
- PE (HDPE/LDPE) and PP are the two premium feedstock types — high oil yield, clean paraffinic/gasoline-range output, freely mixable
- PVC must be kept below 0.1% of the reactor feed — it releases hydrochloric acid gas that corrodes equipment and can cause major plant damage
- PET (clear water bottles) produces acid and CO2 rather than oil — sort it out to below 5% of the feed to protect yield and oil quality
- PS delivers the highest oil yield of any polymer but produces aromatic oil requiring burner management to prevent soot buildup
- MLP produces aluminum residue in the char stream — char screening after each batch is required to recover aluminum and prevent discharge system blockage
Methodology & sources
Polymer characterisations and suitability ratings compiled from pyrolysis industry technical literature and CPCB-published guidance as of 2023–2024. Yield ranges and reactor action recommendations reflect batch and semi-continuous reactor conditions typical of Indian plants at 5–30 TPD scale. PVC contamination threshold of 0.1% is the widely cited industry limit; consult your reactor vendor for equipment-specific tolerance.
Related data tables
Feedstock table 1
This table shows the liquid oil yield, syngas yield, and solid char percentage for four plastic types — pure HDPE/LDPE, pure PP, pure PS, and mixed post-consumer plastic — and describes the primary oil characteristic from each.
output yeild
This table shows the percentage yield and daily/annual output quantities for the four products of a plastic pyrolysis plant — liquid oil, carbon char, syngas, and moisture/loss — modelled at 30 tonnes per day input capacity.
Plastic Pyrolysis Vs Mechanical Plastic Recycling
This table compares plastic pyrolysis and mechanical recycling across four key dimensions: processing method, feedstock tolerance, output quality, and lifecycle outcome.