FURNACE FOR BURNING BIOFUELS Russian patent published in 2023 - IPC F23B10/00 

FIELD: thermal power engineering.

SUBSTANCE: devices for burning biofuels in the form of pellets and wood chips with a size of no more than 50 mm with a relative humidity of up to 30%. The proposed firebox contains a screw feeder of granular biofuel or wood chips into a “U-shaped” burner device, the side, front and rear walls of which expand towards the top and are covered with grates. The bottom of the burner device is made of refractory material and has a recess in the biofuel entry area at the front wall, which serves as a stabilizer for the primary ignition and combustion of the fuel. The firebox contains a combustion chamber equipped with a screw fuel supply device, channels for introducing primary air under the grates of the burner device and secondary air into the nozzles at the side walls, the walls of which are covered with refractory material, and an afterburning and cooling chamber, on the walls of which there is no refractory material, and they transfer heat to the boiler water. In the outlet window of the afterburn chamber there are pipes that provide a connection between the rear wall of the furnace and the boiler ceiling via boiler water and turbulize the combustion products at the exit from the afterburn and cool chamber. The installation angle of the secondary air supply nozzles is reduced to 15-25° to the horizon, and they are located with a half-pitch offset relative to the nozzles of the opposite wall.

EFFECT: angle of inclination of the rear wall of the “U-shaped” burner device is reduced to 30-45° to the horizon, and there is no threshold that prevents spontaneous discharge of ash and slag into the channel for collecting focal residues for their subsequent removal from the furnace; the pipes located in the outlet window of the afterburn and cool chamber have transverse ribs for additional turbulization and cooling of combustion products.

1 cl, 3 dwg