Low-emission swirling-type furnace

A swirl type furnace simultaneously recirculating fuel particles in a low-temperature reduction zone and reburning fine-grained unburned fuel particles in a high temperature oxidation zone, the swirl type furnace comprising:

• a combustion chamber having a front wall, a rear wall and a pair of side walls, the front and rear walls being inclined at a bottom end of the combustion chamber to define, together with said pair of side walls, a prismatic dry-bottom hopper in the bottom end of the combustion chamber;
• a slot-like mouth defined in the prismatic dry-bottom hopper at the bottom end of the combustion chamber;
• a first duct on said front wall introducing a first air/fuel particle mixture flow into said combustion chamber along a first longitudinal axis defined by said first duct;
• a second duct on said front wall introducing a second air/fuel particle mixture flow into said combustion chamber along a second longitudinal axis defined by said second duct;
• an undergrate blast means at the slot-like mouth introducing a counterflow of air directed at said front wall, the counterflow of air mixing with the first and second air/fuel particle mixture flows to form a vortex gas flow, the undergrate blast means and the first and second ducts collectively being adapted to develop reduction and oxidation zones in said combustion chamber and generate said vortex gas flow for repeatedly circulating fuel particles in said reduction zone.

A swirl type furnace simultaneously recirculating fuel particles in a low-temperature reduction zone and reburning fine-grained unburned fuel particles in a high temperature oxidation zone, the swirl type furnace comprising:

• a combustion chamber having a front wall, a rear wall and a pair of side walls, the front and rear walls being inclined at a bottom end of the combustion chamber to define, together with said pair of side walls, a prismatic dry-bottom hopper in the bottom end of the combustion chamber;
• a slot-like mouth defined in the prismatic dry-bottom hopper at the bottom end of the combustion chamber;
• a plurality of ducts on said front wall in a linear array, said plurality of ducts introducing a plurality of air/fuel particle mixture flows into said combustion chamber along a plurality of longitudinal axes defined by said plurality of ducts;
• an undergrate blast means at the slot-like mouth introducing a counterflow of air directed at said front wall, the counterflow of air mixing with said plurality of air/fuel particle mixture flows to form a vortex gas flow, the undergrate blast means and the plurality of ducts collectively being adapted to develop reduction and oxidation zones in said combustion chamber and generate said vortex gas flow for repeatedly circulating fuel particles in said reduction zone.