The Binder underfed combustion system can be found at the heart of some of the worlds finest wood energy installations. The RRF/PRF unit is based around a robust underfed retort burner constructed of scale-resistant chromium cast steel. Fuel is augered into the combustion chamber from below with a minimum number of moving parts.
The system is available in three fuel-feed configurations, with the stoker auger capable of feeding either from the left, right or front of the boiler. This provides excellent flexibility, particularly when retrofitting a Binder boiler into an existing boiler room.
Cutaway of Binder underfed combustion unit
Capable of burning fuel at moisture contents of up to 35%, the RRF is available in configurations suited to both wood chip and wood pellet. It's also possible to reconfigure chip systems to burn wood pellets at a later date should that be desirable.
For applications where pellets will be the only fuel, a PRF pellet combustion unit is used. The PRF is specifically designed for the combustion of pellets in the 6-10mm range, and generates high-quality renewable heat from this refined wood fuel. The grate is cooled from below with the introduction of primary combustion air, and the firebox is lined with a reduced amount of refractory to eliminate overheating and clinkering on fuels with a low ash fusion point.
The RRF/PRF combustion units have a range of features which make them ideally suited to use in schools, office buildings and other commercial and public-sector applications. Equipped with automatic ignition via a powerful 1600W electric igniter, these boilers are typically integrated with building management systems to provide on-demand heating and hot water from carbon neutral wood fuel.
The unit achieves optimum combustion conditions by using a number of sensor-based controls in the boiler operation. Oxygen sensors in the chimney and Binder's innovative flue gas recirculation system, combined with variable speed drives controlling the primary and secondary fans, give excellent combustion efficiencies - typically around 92% - and ultra low particulate emissions. In fact, emissions from a typical school-sized Binder boiler are no more than from a single domestic wood-burning fire!
Binder's patented high-velocity air cleaning system ensures that the excellent efficiency levels and low emissions are maintained throughout the year, without the need for regular cleaning shutdowns. Based around an oversized secondary fan, the cleaning system periodically blasts high-velocity air through the boiler firetubes, dislodging any sooty build up for recovery by the flue cyclone. This gives Binder boilers yet another edge over the competition, who rely either on manual cleaning or supplementary, compressor-based systems to maintain optimum outputs.