METHOD AND DEVICE FOR THE COMBUSTION OF SOLID FUELS

摘要

The invention relates to a method and a device for the combustion of solid fuels using combustion agents containing free oxygen, in particular for an oxyfuel process. According to said method, gases that are charged with dust in the form of fine ash and grit exit the combustion chamber at the top and predominantly coarse-grained products exit the combustion chamber as bottoms, the combustion chamber being supplied with the combustion agents required for complete combustion. The method is carried out in such a way that the combustion chamber is divided into at least one first combustion zone, designed as a moving bed and at least one second combustion zone, located above the first and designed as a highly expanded or circulating fluidised bed, that the division of the combustion chamber is achieved by at least one lateral injection of second combustion agents required for the extensive combustion of the solid fuels, said injection being directed towards the centre of the combustion chamber and the second combustion agents having an oxygen content > 50 % by volume and being injected at a speed > 10 m/s to 100 m/s, that the first combustion agents required for almost complete combustion are injected in a counter-current at the lower end of the first combustion zone, the oxygen content of the gas mixture being restricted to < 50 %, preferably < 21 % to < 10 %, and that the solid fuels are introduced into the combustion chamber to a depth beyond the upper end of the first combustion zone sufficient to prevent the formation of hot-spots at the level of the introduced material and in the area surrounding the latter, in which hot-spots most or all of the ash melts.