Cyclic / batch (batch pyrolysis)

Batch and continuous operation are the two fundamental modes for pyrolysis reactors used in tyre, plastic, and biomass conversion. The choice between them is one of the single most consequential design decisions for any pyrolysis project because it dictates capex, opex, output quality, regulatory pathway, and the scale at which the project becomes financially viable.

Batch pyrolysis loads a fixed quantity of feedstock — typically 5–15 tonnes of shredded tyres or plastics — into a horizontal cylindrical reactor, seals it, heats it from 350–500°C over a 6–12 hour cycle, then cools and discharges. A second reactor allows staggered operation. Batch units dominate the small-scale Indian tyre pyrolysis market because capex is low (₹1.5–3.5 crore for a 10 TPD plant) and they tolerate variable feedstock. However, oil yield is typically 35–40%, char yield is high (25–30%), and labour intensity is significant — workers are needed for every load and unload. Emissions control is harder because the reactor goes through full temperature swings on each cycle.

Continuous pyrolysis feeds shredded material via screw or auger into a heated reactor that maintains steady-state temperature and pressure, with simultaneous product withdrawal. Oil yields are higher (45–55%), gas yields more consistent, and char is finer and more uniform. Continuous plants run 24/7 with 8,000 hours per year of operation, against 4,500–5,500 for batch. The trade-off is much higher capex (₹8–15 crore for the same throughput), tighter feedstock specifications, and a higher minimum viable scale — typically 50 TPD or more. Continuous units also face stricter SPCB scrutiny because emission control systems must be sized for steady operation, but a properly designed continuous plant has a far better chance of meeting the CPCB emission standards introduced in 2022 for both tyre and plastic pyrolysis units.