Process for purifying flue gases containing sulphur oxides and nitrogen oxides

摘要

The invention relates to a process for purifying flue gases containing sulphur oxides and nitrogen oxides, which flue gases additionally still contain residual oxygen, basic dusts and steam. The procedure is carried out in such a way that at least some of the sulphur oxides are converted to sulphur trioxide at an oxidation catalyst and at least some of the sulphur trioxide reacts directly with the basic dusts, forming solid sulphates and/or reacts with the steam, forming sulphuric acid and the sulphuric acid reacts with the basic dusts, forming solid sulphates and the solid sulphates are separated off from flue gases in a device for dedusting flue gases. At least some of the nitrogen oxides in the flue gases can be reduced by addition of suitable reducing agents which are added into the firing space, at least some of the excess of the reducing agent being converted at the oxidation catalyst to ecologically harmless substances.