METHOD AND APPARATUS FOR REDUCING NOX EMISSIONS IN CFB REACTORS USED FOR COMBUSTION OF FUEL CONTAINING LARGE AMOUNTS OF VOLATILE COMBUSTIBLE COMPONENTS

摘要

A method and an apparatus for reducing NOx emissions in CFB reactors used for combusting fuel at atmospheric pressure. The CFB reactor includes a combustion chamber (14), having a fluidized bed of particles therein, a particle separator section including one or more consecutive particle separators (16, 20), a convection section (22) and a clean gas duct (40) connecting the particle separator to the convection section. The apparatus also includes means (54, 56) for injecting ammonia or its precursor into the flue gases, for reducing NOx therein. The ammonia or its precursor is injected into the cleaned flue gases in the clean gas duct (40) connecting the last separator (20) to the convection section (22), the clean gas duct having a very small density of solid particles therein. The temperature in the clean gas duct being sufficient for NOx reducing reactions.