Pyroflex FSR

Flat moving grate firing system 850 to 8000 kW

Specialist for the wood industry

The wood-burning system Pyroflex FSR is designed for the wood industry. The generously dimen­sioned combustion chamber volume and the extensive use of refractory material guarantee low-emissions operation, even with fuels such as chipboard and MDF. The low-NOx combustion chamber is designed with primary-side measures such as air staging to reduce NOx emissions.

Flat moving grate firing system FSR

State-of-the-art combustion technology

Logging and sawmill scraps
Wood processing scraps
Saw shavings

The wood-burning system Pyroflex FSR is designed for the wood industry. The generously dimen­sioned combustion chamber volume and the extensive use of refractory material guarantee low-emissions operation.

Flue gas recir­cu­lation “over” and “under” the grate

The flue gas is drawn into the exhaust line and reintro­duced to the combustion chambers “over” or “under” the grate with a fan. This decreases the flame tempe­rature and reduces nitrous oxides. The efficiency of the system is increased as a result since a lower residual oxygen content remains in the flue gas, even in the case of dry fuels.

For the flue gas recir­cu­lation “under” the grate, the recir­cu­lated flue gas is mixed with the primary air in mixing chambers and then reintro­duced under the grate. The flue gas recir­cu­lation “under” the grate also results in more complete combustion and prevents slag formation on the grate.

Hydrau­li­cally driven flat moving grate

The grate of the Pyroflex FSR is divided into two or three independent grate zones (depending on the unit size). The fuel is distri­buted over the entire grate surface. To achieve optimally complete combustion even with difficult fuels, the grates in the different zones can be operated at different speeds.

Minimal life cycle costs

We place the utmost impor­tance on durability and a long lifespan for our systems. This is achieved by using robust system components. Solid steel construction and the use of high-quality refractory material guarantee reliable system availa­bility for many years. The large grates and the above-average firebox volume signi­fi­cantly reduce wear. Thanks to frequency-controlled screws, grate drives and flue gas recir­cu­lation, we can guarantee minimal power consumption in all load states of the system.

Equipment and access­ories

Measu­re­ments in the primary air and recir­cu­lation air

To achieve optimal combustion results and emissions values in all load stages, including with difficult fuels, the flow rates of primary air and flue gas recir­cu­lation are measured and the required air quantities are calcu­lated in advance. The grate of the Pyroflex FSR is divided into four independent primary air zones. This allows the required air quantities to be adapted to the fuel.

Use of high-quality O2 probes

The secondary air flow rate is regulated based on the detected oxygen level. High-quality O2 probes make it possible to maintain a conti­nuously low residual oxygen level in the flue gas (approx. 4–5% O2 (damp) – depending on the fuel). This allows the highest levels of efficiency to be achieved even in modulating partial load operation.

Automatic ash removal

Several variants are available for removing ash from the combustion chamber as well as the cyclone and electro­static filter, depending on the fuel and ash content. The ashes can be discharged jointly or separ­ately. They are deposited into containers of up to 800 l or in settling pits of 5.5 to 12 m2. They can also be filled into big bags.

The following variants are available:

  • With trough chain conveyor
  • With screws
  • Laterally from the combustion chamber
  • Directly under the combustion chamber
Sectional drawing FSR
  1. 3-pass boiler (6.0 bar – higher pressure ratings on request)
  2. Safety heat exchanger (integrated into boiler)
  3. Flat moving grate, hydrau­li­cally driven (divided into two or three zones, depending on type) with injection of the primary air (4 zones)
  4. Injection of secondary air
  5. Injection of flue gas recir­cu­lation “above the grate”
  6. Hydraulic infeed / direct infeed with water-cooled infeed neck or infeed screw
  7. Automatic combustion chamber ash removal
  8. Firebox doors
  9. Injection of flue gas recir­cu­lation “under the grate”
  10. Pneumatic boiler tube dedusting

Profit from these benefits:

  • Fully automatic wood-burning system with flat moving grate 850 to 8000 kW
  • Fuel water content: 6 to 55%, ash content (share of foreign matter) up to 6%
  • Four independent combustion air supply zones under the grate enable optimal combustion condi­tions in every phase of the grate.
  • The use of frequency-controlled screws, grate drives and fans for the flue gas, secondary air and recir­cu­lation ensures minimal power consumption in all load ranges of the system
  • High wear resis­tance thanks to large grate surfaces and water cooling of the grate support and sides of the grate
  • Modulating load regulation from 25 to 100% of the rated heat output in compliance with the emissions values

Optional access­ories

  • Pneumatic boiler tube dedusting (signi­fi­cantly extends the time between cleanings)
  • Automatic ignition system (automatic ignition for fuels with a water content of up to 35%)
  • Flue gas recir­cu­lation “under” the grate (increases efficiency and reduces nitrogen oxides, plus cooling of the grate)
  • Remote maintenance and visua­li­sation systems (full system access from a PC, tablet or mobile phone)
  • Raising of the flue gas tempe­rature (to avoid conden­sation in the flue gas path and in downstream components)
  • Nitrogen oxide reduction system (for reducing of NOx emissions with the SNCR method)
  • Conti­nuous emissions measu­rement
  • LUVO (preheating of the primary air for wet fuels)
  • A firebox camera for monitoring the firebox is an optimal addition to a visua­li­sation system


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Example instal­lation

District heating plant for a city

Firing system: 2x Pyroflex FSR
Output: 2600 kW each
Fuel: Wood from lands­caping M45

Anlagenbeispiel FSR
  1. Fuel storage in reserve bin with crane feeding
  2. Daily supply bin with moving floor discharge
  3. Hydraulic fuel transport
  4. Firing system: 2x Pyroflex FSR
  5. Ash r