Method and arrangement for reduction NOx emissions in reactors with a circulating fluidized bed used for combustion of fuels containing large amounts of volatile combustible components

摘要

Method and arrangement for reduction of NOx emissions in CFB reactors intended for combustion of fuels at atmospheric pressure. A CFB reactor 12 includes a combustion chamber 14 in which a fluidized bed formed with particles is incorporated, a particle separator part in which one or more particle separators 16, 20 arranged after each other are incorporated, a convection part 22 and a channel 40 for clean gas, said channel connecting the particle separators to the convection part. The arrangement also includes a device 54, 56 for injection of ammonia or a substance forming ammonia into the flue gases to reduce the NOx entering the gases. The ammonia or substance that forms ammonia is injected into the purified flue gases into a channel for clean gas which connects the convection part to the separators and in which the particle density for solid particles is very low and the temperature sufficient for the NOx reduction reactions. <IMAGE>