Structure and Working Principle of a Grate Incinerator

Structure and Working Principle

Waste enters the incinerator through the feed inlet and lands on the grate. It first goes through the drying stage, where moisture is evaporated by the high-temperature hot gas in the furnace. As the grate moves, the waste is slowly pushed forward into the combustion stage. There, with sufficient air supply, the waste burns fully, producing high-temperature flue gas and heat. Finally, the burnt residue is discharged from the end of the grate, while the high-temperature flue gas enters the downstream flue gas treatment system.

A grate-type incinerator mainly consists of a set of grates, usually including fixed grates and moving grates. The fixed grate supports the fuel, while the moving grate is driven by a mechanical device to move left/right or front/back. The shape and arrangement of grate bars vary; some overlap like fish scales, which prevents waste from falling through the grate gaps and also helps stir the waste during movement.

A ventilation system below the grate delivers air evenly into the waste layer above. Depending on the combustion stage, the ventilation system can adjust the air volume in different zones.