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What's the Difference Between Batch, Semi-Continuous, and Fully Continuous Pyrolysis Plants for Waste Tires?
Industry News / Date:November 4, 2026
When buyers compare waste tire pyrolysis plants, the choice usually comes down to three classes. The short answer to how they differ: batch pyrolysis plants take whole tires and run one cycle at a time; semi-continuous pyrolysis plants take 16–18 mesh rubber powder and run in scheduled cycles, commonly two days out of three; and fully continuous pyrolysis plants take powder below 5 mm and run for 45–60 days between planned stops. Everything else — pre-treatment cost, automation, labor, maintenance, site works — follows from those feeding rhythms, and the same batch cycle also comes skid-mounted for the smallest sites. Which class fits is decided less by capacity than by your tire supply, site and budget.
Different pyrolysis solutions for various project scales
1. How the Three Tire Pyrolysis Processes Work
All three feed a rotating reactor, heat it under sealed, oxygen-free conditions, condense the vapour into oil, burn the non-condensable gas in the furnace and discharge carbon black and steel wire. Tire cracking happens at 320–350°C, at atmospheric pressure below 2 kPa, in every class.
The classes divide on two points only: what goes into the reactor — whole tires or powder — and how the reactor is fed and emptied, whether batch by batch, in scheduled cycles or continuously. Cost, labor, carbon black quality and site works all trace back to those two points, which is why the rest of this article is organised around them.
2. Batch Tire Pyrolysis Plant
Working process. Whole tires are pushed in by a hydraulic feeder through a 1.4 m door. One cycle — load, heat, condense, cool, discharge — takes about 20 hours, with the vapour passing through up to four stages of condensation. Forced cold air brings the reactor down in roughly 4–5 hours.
Feedstock. No rubber-powder line is needed: no washing, shredding or wire pulling before the feed. The only physical limit is the door — anything that fits goes in. Naturally, it is better if the tires are already shredded.
Capacity and cycle. Batch pyrolysis plants span 1 to 20 tonnes per day. Small 1–5 tonne reactors suit trials and pilot lines; 10, 12 and 15 tonnes are the common tire configurations, and the top of the band is also configured for plastics and aluminum-plastic waste. Projects reach volume by running several reactors in rotation.
Advantages. Lowest entry investment, the shortest path from delivery to first oil, tolerance of irregular tire supply, and a free choice of front, side or rear discharge to suit the yard.
Limitations. Carbon black tends to carry higher ash, labor and cooling time are counted per reactor, and a single reactor cannot match the output of a continuous line.
Whole tires processed one cycle at a time
3. Skid-Mounted Tire Pyrolysis Plant: Batch Mode in a Movable Frame
What it is. A skid-mounted tire pyrolysis plant runs the batch cycle described above, but the reactor, condensing stage and control cabinet are mounted, piped and pressure-tested on skid frames before leaving the factory. On site the modules are placed, connected to power and water, and brought online — the whole plant leaves the works assembled, which is what makes installation quick and later relocation possible.
Capacity and use. It occupies the small end of the batch band, 100kg/500kg per day. Typical users are pilot lines, small dealers proving a market before scaling up, and sites where a full civil project is not yet justified.
Trade-offs. Cycle time, oil yield and the front, side or rear discharge options follow the batch section above. What it gives up is scale: output is capped by the small reactor, so growth means adding modules rather than upsizing one, and the per-tonne economics only hold while volumes stay small.
Compact design with factory-assembled modules
4. Semi-Continuous Tire Pyrolysis Plant
Working process. Powder is fed through an enclosed screw and a ball valve, so the reactor never opens to air while hot. A buffer tank with a pressure gauge and relief valve guards the vapour path before the condensers. Oil starts flowing in roughly 10 hours.
Feedstock. Tires must already be 16–18 mesh rubber powder, with the steel wire recovered at the milling stage — where it comes out bright and clean, the grade steel buyers pay for.
Capacity and cycle. Semi-continuous pyrolysis plants are configured between 5 and 20 tonnes per day. In the common arrangement the plant runs two days out of every three: one batch discharging through a water-cooled screw while the next processes, the carbon black leaving hot and sealed.
Advantages. Investment sits between the other two classes; several reactors can share one purification backend, so environmental systems are not multiplied per reactor; the powder requirement is easier to satisfy than a continuous line's.
Limitations. It still needs a milling line, and its output per line stays below a fully continuous pyrolysis line, so growth beyond the band means adding reactors or moving class.
Rubber powder feeding with scheduled production cycles
5. Fully Continuous Tire Pyrolysis Plant
Working process. Powder below 5 mm enters through a metering belt and conveying screws. An internal propeller moves material forward as the reactor rotates, and slight negative pressure draws the vapour backwards so oil vapour and carbon black separate cleanly. A hot-air furnace holds temperature across the run, under PLC control.
Feedstock. Powder with the wire fully removed — nothing oversized passes. The mill has to match the reactor: a 30-tonne-per-day line needs roughly 2.5 tonnes of powder per hour to keep the metering belt fed.
Capacity and cycle. A continuous pyrolysis plant runs lasts 45–60 days between planned stops; that is a maintenance interval, not a promise of never stopping. Reactor size steps up with tonnage — about 1.6 m diameter with 16 mm boiler plate at 30 tonnes per day, 2.0 m with 18 mm plate at 50. DOING ECO builds these lines at 15, 20, 30, 40 and 50 tonnes per day.
Advantages. Fewest people per tonne, steady conditions that keep carbon black quality consistent, about 12% of output as non-condensable gas that larger projects pressurize and clean to run a generator, and continuous discharge through three-stage water-jacketed screws.
Limitations. Highest total investment once the milling line is counted, no tolerance for powder shortfalls, and maintenance has to be planned into the calendar rather than squeezed between batches.
Automated production for long-term operation
6. Batch vs Semi-Continuous vs Fully Continuous: A Detailed Comparison
| Item | Skid-mounted (batch mode) | Batch | Semi-continuous | Fully continuous |
|---|---|---|---|---|
| Feed form | Whole tires, small door | Whole tires | 16–18 mesh powder | Powder below 5 mm |
| Pre-treatment | None | None within the 1.4 m door | Shredding and milling line | Milling line, wire fully removed |
| Feeding | Manual or hydraulic, small door | Hydraulic feeder | Enclosed screw + ball valve | Metering belt + conveying screws |
| Operating rhythm | ~20 hours per cycle | ~20 hours per cycle | Scheduled cycles, commonly two days out of three | 45–60 days between planned stops |
| Capacity per line | 100kg/500kg per day | 1–20 t per day (10–15 t common for tires) | 5–20 t per day | 15 / 20 / 30 / 40 / 50 t per day |
| Installation | Factory-assembled modules, placed and connected | On-site assembly | On-site assembly | On-site assembly, longest |
| Automation | Simple, operator-led, can be equipped with PLC. | Simple, operator-led, can be equipped with PLC. | Partial, per cycle, can be equipped with PLC. | PLC-controlled, continuous |
| Labor | One crew per reactor | Per reactor, rises with reactor count | Depends on line layout | Lowest per tonne |
| Discharge | Front, side or rear, as batch | Front, side or rear after cooling | Water-cooled screw, hot and enclosed | Three-stage water-jacketed screws |
| Carbon black | Tends to higher ash, as batch | Tends to higher ash | Intermediate | Tends to lower ash |
| Initial investment | Lowest of all four | Lowest of the three main classes | Middle, close to batch | Highest, including milling line |
| Indicative budget (reactor line) | About USD 11,000–38,000 | About USD 50,000–120,000 | About USD 60,000–150,000 | About USD 400,000–1000,000 |
| Site and utilities | One small pad, smallest water system | Several reactor pads, small water system | Powder line plus reactor area | Full line footprint, largest water system |
| Fits best | Trials, small lots, quick start, relocation | First plant, irregular supply | Steady powder, mid-size output | Large, long-run projects |
Note one overlap worth knowing: semi-continuous pyrolysis plant reaches 20 tonnes per day and fully continuous pyrolysis plant starts at 15, so between 15 and 20 tonnes per day both classes are technically offered. The tie-break is not capacity but powder reliability, budget and how continuously you want to run.
The budget figures above are indicative ranges for the pyrolysis line itself. Final quotations move with configuration, and freight, site works and installation are priced separately.
7. Investment and Running Costs: Where the Money Goes
| Cost item | Skid-mounted | Batch | Semi-continuous | Fully continuous |
|---|---|---|---|---|
| Pyrolysis reactor line | Lower still | Lower | Middle | Higher |
| Milling and wire separation | Not required | Not required | Required | Required, sized to the reactor |
| Automation and controls | Simple | Simple | Partial | PLC, sensors, interlocks |
| Labor | One crew | Per reactor | Per line | Lowest per tonne |
| Civil works and site | One small pad | Multiple pads, shorter units | Reactor area plus powder line | Longest footprint plus conveyors |
| Maintenance | As batch, one reactor | Spread across more reactors | Screws, valves, seals | Planned stops, wear parts on conveyors |
| Utilities | Smallest | Small cooling system | Medium | Largest cooling and power demand |
Two things explain why a fully continuous pyrolysis line can still be the cheaper plant per tonne at scale, without quoting a single figure. First, the capital cost is paid once while the labor, fuel and floor space are paid every month — and the continuous design spreads all three over far more tonnes. Second, the powder line that makes continuous pyrolysis plants expensive is also the line that turns scrap tires into a saleable grade of steel wire and a consistent feed, so part of that investment earns its own revenue.
The reverse holds too. A project collecting a few tonnes of tires a day does not gain from a continuous line's rhythm, because the mill and the reactor would both sit idle between deliveries — the smaller class carries less capital for the same output.
Automated monitoring and process control
8. How to Choose: Five Questions in Order
Step 1 — What form is your feed? Whole tires point to a batch pyrolysis plant. Powder points to semi-continuous or fully continuous, and the milling line becomes part of the project.
Step 2 — How stable is the supply? Seasonal or irregular collection suits batch operation, where each reactor starts when material arrives. Steady daily supply is what makes a scheduled or continuous line worth its capital.
Step 3 — What is your daily target? Under 5 tonnes, a skid-mounted pyrolysis plant or a small batch pyrolysis reactor is the honest answer. Between 5 and 20, batch pyrolysis reactors in combination and semi-continuous pyrolysis lines cover the band. Above 20, fully continuous replaces a battery of reactors with one line.
Step 4 — What do you already own? An existing milling line changes the arithmetic completely — check its real hourly output against the reactor's appetite before choosing a class. No milling line means either adding it to the budget or choosing batch.
Step 5 — What is the five-year plan? Batch and semi-continuous pyrolysis plants suit businesses that expect to change feedstock or scale gradually. Long-term, single-product, high-volume operation is what a continuous line is built for.
9. Four Typical Project Scenarios
| Scenario | Project conditions | Sensible direction |
|---|---|---|
| Pilot line or small dealer | A few hundred kilograms to 2 t per day; fast start wanted; site may change | Skid-mounted pyrolysis plant, factory-assembled modules, or Batch pyrolysis plant |
| Small collector or first plant | Limited, irregular tire collection; no milling line; tight budget | Batch pyrolysis plant, two reactors, whole-tire feeding |
| Mid-size recycler with powder supply | Steady 16–18 mesh powder from a local mill or own line; 5–20 t per day | Semi-continuous pyrolysis plant, reactors sharing one purification system |
| Large tire recycling plant | Own shredding and milling line; long-term contracts; 20 t per day and up | Fully continuous pyrolysis plant, mill sized above reactor demand |
| Powder line already built, capital limited | Milling capacity exists; the continuous line is out of reach this year | Semi-continuous pyrolysis plant now, continuous line later on the same site |
These are directions, not rules. Two projects at the same daily tonnage can land in different classes once the powder supply, budget and site are counted — which is exactly why the quotation step matters.
10. Maintenance, Site and Environmental Requirements
Maintenance and downtime. Batch pyrolysis plants stop between every cycle for cooling and discharge, so maintenance fits into natural gaps. A continuous pyrolysis plant runs for weeks and then stops for a planned service window; wear parts sit mainly in the conveying and discharge systems, where the screws and jackets do the work. Neither class runs unattended forever.
Site and utilities. Beyond the reactor pad, a continuous project needs space for the milling line, powder storage, conveyors, carbon black handling and product tanks, plus power capacity for the mill and the largest cooling system of the three. Batch pyrolysis projects need several smaller pads and room to turn vehicles between reactors.
Environmental control. Every class carries sealed feeding, condensed vapour recovery, non-condensable gas burnt in the furnace, desulfurization and dust removal, and enclosed carbon black handling. What changes with scale is the volume to be handled and how automated the monitoring is — a continuous pyrolysis line's steady flue gas is easier to control than the start-and-stop profile of batch cycles. Sealed feeding alone does not make a project compliant; local emission limits decide the configuration, and DOING ECO sizes desulfurization, dust removal and monitoring to the limits a project has to meet, from a basic scrubber set to a full flue-gas chain.
Flue gas desulfurization and dust removal
11. What to Prepare Before Asking for a Quotation
| Information | What it decides |
|---|---|
| Daily processing target | Reactor size and number of units |
| Tire types and sizes | Whether whole-tire feeding is possible |
| Whole tires or powder | Pre-treatment requirement |
| Daily tire supply and its stability | Batch, scheduled or continuous operation |
| Existing milling equipment and its hourly output | Whether line capacity matches the reactor |
| Available land and layout | Reactor pads, powder line and storage areas |
| Power supply and fuel availability | Mill drives, furnace and gas use |
| Cooling water source and space | Pond or cooling tower sizing |
| Target products and buyers | Carbon black handling and oil storage |
| Local emission requirements | Desulfurization, dust removal, monitoring scope |
With those ten answers a configuration can be costed as a whole — reactor, milling line and environmental systems together, not as three separate budgets that later fail to match.
FAQ
Can I start with batch pyrolysis plants and move to a fully continuous pyrolysis plant later?
Yes, and many buyers do — starting with a 2-plus-2 or 2-plus-4 arrangement of batch pyrolysis reactors, then adding a continuous line as volume grows. What you cannot do is convert one into the other: the feeding, discharging and control systems share nothing between classes. The real precondition for going continuous is not capital but powder — the milling line has to exist first, so it is worth planning the site for it even in year one.
How many batch pyrolysis reactors does a real project run?
Almost always an even number: two, four or six. Reactors are paired so the firing zones face each other, one firing worker can watch two reactors at once, and the piping runs stay short. A 20,000-tonne-per-year tire project typically lands at four to six reactors. At six to eight, the tail-gas volume becomes large enough to recirculate completely across the group, which cuts fuel purchases visibly.
When does a skid-mounted plant beat a fixed batch pyrolysis plant — and when not?
Below roughly 5 tonnes per day. There, a fixed batch layout carries civil works and a multi-reactor yard sized for growth a small site may never see, while skid modules arrive factory-assembled and start production after connection to power and water — and can move to a new site if the material supply shifts. Past that tonnage the arithmetic reverses: fixed batch reactors price better per tonne, pair into the shared-furnace arrangements described above, and grow by adding units on one yard.
Can one plant handle different tire sizes?
Within one class, yes. A batch pyrolysis reactor's limit is the door: passenger, truck and agricultural tires all fit, while oversized off-the-road tires have to be cut down first. In powder-fed classes the limit moves to the mill and the screen, and mixing very different rubber grades in one run makes the oil and carbon black less consistent, so batches are usually kept separate by source.
What happens if the powder supply falls short of a continuous pyrolysis line's demand?
The reactor is designed around steady feed, so a shortfall shows up quickly — the metering belt runs light, temperature and pressure drift, and the line has to be held rather than run badly. Operators keep a buffer of milled powder on site and plan mill capacity above reactor demand; sizing the mill to exactly match the reactor leaves no room for a breakdown at the shredder.
How much cooling water does each class need?
The condensing side is water-hungry, and the difference between classes is large. As a reference configuration, a 50-tonne-per-day fully continuous pyrolysis line works with a cooling pond of around 200 cubic metres; a batch line runs from 40 cubic metres upward, usually planned at 50. Where the site cannot spare the area, a cooling tower replaces part of the pond, and inlet water temperature matters more than volume.
Can a semi-continuous pyrolysis plant process anything besides tires?
Its separate solid and liquid feed ports let one batch take rubber powder and the next take a pumpable feed — oily sludge being the usual example — without changing the reactor. That flexibility is a side benefit rather than a reason to choose the class, since sludge projects have their own permitting and reactor requirements, and they are usually planned as dedicated oily sludge pyrolysis plants.
Send your daily tonnage, the form your tires arrive in — whole, shredded or milled — and your site conditions, and the class can be narrowed to the one your project can keep running. DOING ECO quotes the reactor line, the milling line and the environmental systems as one configuration, and sends engineers for installation and operator training on whichever class is delivered.
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