Bidding Farewell to Fuel Size Constraints: Costs and Advantages of the "Walking Floor" Medium-Scale Biomass Incinerator

In wood processing plants, paper mills, agricultural reclamation zones, and regional heating centers, processing agricultural and forestry waste often involves dealing with irregularly shaped wood chips (10–50 mm), baled bagasse, long straw sections, and tangled baling twine.

When handling these challenging fuels, the traditional screw feeders (shafted or shaftless) commonly equipped on a medium-scale biomass incinerator frequently suffer from three chronic issues: tangling, bridging, and jamming. Once a screw flight is seized by fibrous ropes or long materials, it not only halts operation but requires dismantling for manual clearance, driving up maintenance costs.

To completely break the rigid limitations on fuel size and morphology, the "Walking Floor" (moving floor) feeding system has emerged. Utilizing a hydraulically driven series of chain-linked flat plates that alternate lifting, translating, and lowering motions, it acts like a combination of a conveyor belt and a bulldozer. It smoothly pushes chaotic, large-sized fuel into the furnace without any rotating engagement, physically eradicating the root cause of jamming.

Below, we deeply deconstruct the cost breakdown and technical advantages of a medium-scale biomass incinerator equipped with this system.

The Inherent Flaws of Screw Feeding: Why the Medium-Scale Biomass Incinerator Needs a Walking Floor Revolution

A typical medium-scale biomass incinerator—handling 0.5–6 t/h (steam equivalent) or 200–500 kg/h (waste incineration version)—is usually paired with a shaftless screw feeder. This leads to:

• Tangling and Jamming: Baling twine and long fibers mixed within rice husks or straw wrap around the screw axis, causing motor overload and tripping.

• Bridging and Idling: Wet bagasse or compacted wood chips form an arch (bridge) over the hopper outlet, causing the screw to spin empty without feeding fuel.

• Strict Size Limits: Screw clearances generally require material <30 mm. Large, chunky wood chips (>50 mm) simply cannot enter.

The Walking Floor Mechanism:

Composed of a set of chain-linked flat plates at the bottom of the bunker:

1. The first group of plates lifts, supporting the material, and translates forward.

2. The plates lower and retract to their original position, while the material remains forward due to gravity and friction.

3. The next group of plates repeats the action, creating a "walking" push.

Because there are no rotating, biting components, there is virtually no restriction on fuel length or shape (capable of handling 500–1000 mm long wood strips or baled blocks), and the massive hydraulic thrust makes jamming nearly impossible.

Cost Breakdown: Medium-Scale Biomass Incinerator with a Walking Floor

A walking floor system is mechanically more complex and relies on sophisticated hydraulic controls compared to a screw feeder, resulting in a higher total equipment price.

Taking a medium-scale biomass incinerator with a processing capacity of 300–500 kg/h (thermal equivalent of a 2–3 t/h steam boiler) as an example:

Note: If comparing a fully loaded medium-scale biomass incinerator (including dual-chamber, rapid quench purification, and heat recovery) where the total price is already in the ¥300,000–¥450,000 range, the absolute price difference of the walking floor is diluted by the overall environmental configuration.

Operational Advantages After Eliminating Jams: Continuity and Fuel Tolerance

1. "Zero Pickiness" for Fuel Size and Shape

• Directly accepts long straw sections (200–500 mm), irregular wood chips (>50 mm), baled bagasse blocks, and even lightly mixed construction waste wood.

• Eliminates the need for excessive crushing down to <30 mm, saving massive crusher electricity costs and blade wear.

• Pushes high-moisture fibrous materials (like 50% moisture fresh bagasse) stably, without the sticky clumping that jams screws.

2. Drastically Improved Uptime and Lower Maintenance

• A screw jam typically requires 2–4 hours of furnace downtime to dismantle and clear. The walking floor has near-zero jam risk, reducing unplanned annual downtime by over 70%.

• The chain plates are made of high-strength wear-resistant steel (NM360/400) and only require localized replacement every 3–5 years, far outlasting easily worn screw flights.

3. Superior Sealing and Anti-Backfire Safety

• Walking floor inlets are usually equipped with a dual air-lock system (hydraulic gate + gravity flap). Combined with micro-negative pressure control (-20 to -50 Pa), the backfire risk is lower than a screw feeder (where the central hollow space can conduct fire).

• The hydraulic system features overload pressure relief. If it hits an immovable hard object (rock/solid metal), it automatically yields and alarms, preventing damage to the main structure.

4. High Bunker Utilization and Automation

• Pairs perfectly with large-capacity trapezoidal bunkers without the need for forced arch-breaking devices. Material piles naturally and is pushed out by the plates.

• PLC Integration: Automatically adjusts the walking frequency (pushing speed) based on furnace temperature or steam pressure, achieving true "on-demand" feeding rather than the brute-force constant speed of a screw.

Multi-Dimensional Comparison: Choosing the Right Feeding System

Application Scenarios: Who Should Buy a Walking Floor Medium-Scale Biomass Incinerator?

We strongly recommend prioritizing the Walking Floor system for the following scenarios:

• Wood Processing Plants: Handling offcuts of varying sizes (strips, shavings, broken boards).

• Sugar / Paper Mills: Dealing with baled bagasse blocks, long-fiber residues, and wet/sticky bases.

• Agricultural Zones: Feeding corn/wheat stalks (200–500 mm) directly into the furnace without fine crushing.

• Refuse-Derived Fuel (RDF) Lines: Handling irregular shapes mixed with twine and plastics.

If your fuel is entirely uniform 6–8 mm pellets or <20 mm crushed rice husks, and you are highly constrained by space and budget, a conventional screw-fed medium-scale biomass incinerator remains cost-effective. However, if your fuel is "wild" in shape and large in volume, the initial premium of a walking floor will be recovered within 1–3 years through reduced downtime, saved crushing costs, and lower labor.

BNTET Customized Solutions: The Walking Floor Medium-Scale Biomass Incinerator

The BNTET medium-scale biomass incinerator (BM-WF Series, processing 200–500 kg/h or 1–6 t/h steam equivalent) offers tailored Walking Floor integration:

• Dual-Chamber Pyrolysis-Oxidation: Primary chamber 600–750°C hypoxic pyrolysis; secondary chamber ≥850°C (≥900°C for plastics/pharma residues) with CFD-verified ≥2s residence time.

• Walking Floor System:

• Chain plates use NM360 wear-resistant steel; hydraulic station power 5.5–11 kW (thrust-dependent).

• PLC proportional valve controls walking frequency (0.1–1.0 m/min stepless).

• Airlock & Sealing: Feed inlet features a hydraulic gate + gravity flap dual airlock, interlocked with micro-negative pressure (alarms and halts pushing if pressure > -5 Pa).

• Bunker Adaptation: Compatible with large trapezoidal bunkers (1–3 m³) with angled floor plates to prevent material stagnation.

• Anti-Slagging Lining: High-alumina low-cement + SiC in the primary chamber to resist alkali/silica attack; corundum in the secondary chamber, anchored with 310S.

• Smart Control Integration: PLC displays furnace temp, walking frequency, hydraulic pressure, and furnace negative pressure. Includes USB data export and alarms for over-temp, overload, and open doors.

Fuel size and shape limitations should never become the bottleneck for the stable operation of a medium-scale biomass incinerator. The tangling and jamming of screw feeders translate into downtime losses and maintenance costs that quickly cancel out their initial low price.

The Walking Floor system, with its "lift-translate-drop" hydraulic chain plate mechanism, physically eradicates the jamming risks associated with rotating engagement, comfortably handling everything from 6 mm pellets to 500 mm wood logs and baled bagasse.

By deeply integrating the dual-chamber pyrolysis process with a Walking Floor feeding system, the BNTET medium-scale biomass incinerator offers a quantum leap in continuous operation rates and fuel tolerance for a mere 15%–25% price premium. It is the ultimate solution for the "rough but voluminous" waste streams of the timber, sugar, paper, and agricultural industries, ensuring every irregular scrap is steadily, smokelessly, and continuously converted into thermal energy or volume-reduced ash.