Method for injecting a substance into a boiler of a waste incineration plant

A method for injecting a substance into a boiler (4) of a waste incineration plant, using a gaseous propellant, the substance being conducted, starting from at least one distributor (8), via lines (14a-i) which branch off from the distributor (8), in each case to a nozzle (16a-i) which is assigned to the respective line (14a-i) and by means of which the substance and the propellant are injected into the boiler (4), and the substance quantity to be conducted to the respective nozzle (16a-i) being set in the distributor (8), wherein the boiler (4) is subdivided into multiple boiler sectors (4a-d), in which the nozzles (16a-i) are arranged in a plurality of horizontal nozzle planes, and to each boiler sector (4a-d) at least one separate distributor (8) is assigned, and the substance and the propellant are combined upstream of the branch-off with the respective line (14a-i).