Low-emission furnace for wastes, in particular domestic refuse

摘要

The invention relates to a low-emission furnace for wastes of the domestic refuse type, which have been coarsely comminuted and freed of iron parts and inert material (glass, stones...). The combustion is divided into the three known stages: burning-out of carbon-containing residues, low-temperature carbonisation of the feed material with an oxygen deficit, and combustion of the carbonisation gases with secondary air. The first stage takes place in a relatively narrow shaft furnace or fluidised-bed furnace, the second stage takes place in a widened shaft which is arranged above the former and is closed at the bottom via a collection funnel by a movable grate and which, above the bed, has means for smoothing out the surface of the bed layer, the fly ash being largely filtered out by the bed layer, and the third stage takes place in an after combustion chamber with secondary air nozzles, for example just upstream of a waste heat boiler. The temperature in the first stage is maintained by known means at 900 DEG K, and basic additives, for example powdered lime, are added in order largely to bind chlorine and sulphur inside the furnace.