Stepped grate firing system 850 to 10000 kW
The stepped grate firing system is particularly suited to the combustion of wood fuels with a high water content of up to 60% and an ash content of 10%. These conditions allow the flexible use of inexpensive, undried fuels such as forest wood chips, green cuttings, bark, wood from landscaping, short-rotation woody crops and mature timber. The wood-burning system Pyroflex SRT with stepped grate firing system is designed for continuous operation of up to 8000 hours per year.
Designed for continuous operation
Fuels:
Wood from landscaping
Bark
Green cuttings
Mature timber
Short-rotation woody crops
Special fuels
The Pyroflex SRT is particularly suited to the combustion of wood fuels with a high water and ash content. These conditions allow the flexible use of inexpensive, undried fuels.
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.
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. Minimal power consumption in all load states of the system is ensured by frequency-controlled screws, grate drives and flue gas recirculation.
Equipment and accessories
Measurements in the primary air and recirculation air
The flow rates of the primary and recirculation air are measured, and the required air quantities are calculated in advance. This achieves optimal combustion results and emissions values in all load stages, including with difficult fuels. The grate of the Pyroflex SRT is divided into up to 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