Direct answer
Which pyrolysis machine should you use?
If the feed is lumpy, wet or contaminated, buy a rotary kiln or an auger. If the feed is dry, sized and you want oil, buy a fluidised or spouted bed with a fast quench. If you need precise temperature for sludge or battery binder, buy an electrically heated screw. Microwave and plasma are not drop-in replacements for a 2 t/h mixed-waste kiln.
| Reactor | Best product | Feed tolerance | Heat / dwell | TRL | Watch-outs |
|---|---|---|---|---|---|
| Fixed / batch bed | Char, lab oil | High | Slow, hours | 9 (charcoal) / 4 (oil) | Not a continuous plant |
| Rotary kiln (indirect) | Char, rCB, BM | Very high | Minutes–hours | 8–9 | Vapour time poorly controlled |
| Auger / screw (fuel-fired) | Char, oil | High if pre-shredded | Minutes, set by rpm | 8–9 | Screw wear, seals |
| Electrically heated screw (Spirajoule / Biogreen) | Char or oil | Medium–high | 200–800 °C, set by Joule + rpm | 8–9 | Power price; dielectric not required |
| PYREG-class carboniser | Sludge biochar | Dried sludge, organics | ~500–700 °C, minutes | 8–9 | Needs dryer + gas oxidiser |
| Moving bed (Pyrum-type) | Tire oil + rCB | Granules | 500–750 °C, ≥1 h | 8 | Feed spec, rCB quality |
| Bubbling / circulating fluid bed | Bio-oil | Low (size, density) | Seconds, 450–550 °C | 7–8 | Metals, melt, attrition |
| Conical spouted bed | Plastic oil, less wax | Sticky particles better than BFB | 500–600 °C | 6–7 | Complex, cost |
| Rotating cone / ablative | Bio-oil | Low–medium | Very high HR | 6–7 | Scale and wear |
| Vacuum retort | Oil (tires, wood) | Medium | Lower T, less secondary crack | 6–8 | Seals, vacuum train |
| Microwave-assisted | Oil, designer carbons | Needs absorber if transparent | Volumetric, up to hundreds °C/s | 5–7 | Penetration depth, scale |
| Thermal plasma | Syngas, vitrified slag, H2 | Hazardous, mixed | 10³–10⁴ °C locally | 5–8 (duty-specific) | kWh, not selective oil |
| Battery rotary calciner | Black mass | Shredded cells | 300–1200 °C, N2 | 8 | HF, explosion, Cu oxidation |
What plants actually run (not a vendor catalogue)
- Biochar / sludge: auger and rotary kilns are >60% of reported industrial biochar capacity (IBI/USBI synthesis in SusMat 2026). PYREG + SUEZ Pyrolis S2B (2026) is the municipal sludge pattern: dry to ~90% DS, pyrolyse ~600 °C, oxidise gas >950 °C.
- Tires: augers at 4–400 kg/h have now been shown to match yields (Energy & Fuels 2024). Pyrum moving-bed is a named industrial oil + rCB line. Enviro-class and similar Scandinavian plants sit in the same product triangle.
- Plastics: Plastic Energy, Quantafuel/BASF, Agilyx, Brightmark-class thermal/catalytic trains — all live or die on sorted polyolefin and on oil upgrading, not on the kiln brand.
- Batteries: Accurec-style pyrolysis vs Duesenfeld vacuum drying vs Umicore smelting (>1000 °C, not pyrolysis). China GB/T 45203-2024 now names recycled black mass as a product.
Heating method is a process variable
Fuel-fired jackets are cheap where gas is cheap. Electric screws and kilns buy you atmosphere control (no tramp oxygen), ramp precision, and a path to low-carbon power — which matters for battery HF chemistry and for PFAS vapour containment. Plasma is electric too, but it is an energy density play, not a 500 °C oil play.