The spreader stoker is capable of burning a wide range of coals, from high-rank eastern bituminous to lignite or brown coal and a variety of by product waste fuels.
As the name implies, the spreader stoker projects fuel into the furnace over the fire with a uniform spreading action, permitting suspension burning of the fine fuel particles. The heavier pieces, that cannot be supported in the gas flow, fall to the grate for combustion in a thin fast burning bed. This method of firing provides extreme sensitivity to load fluctuations as ignition is almost instantaneous on increase of firing rate and the thin fuel bed can burned out rapidly when desired.
The modern spreader stoker installation consists of feeder distributor units in widths and numbers as required to distribute the fuel uniformly over the width of the grate, specifically designed air-metering grates, forced draft fans for both undergrate and overfire air, dust collecting and reinjecting equipment and combustion controls to coordinate fuel and air supply with load demand.
