METHOD FOR PURIFYING EFFLUENT GASES

摘要

The present invention relates to the purification of exhaust gases from non-stationary internal combustion engines such as those used in petrol or diesel vehicles, as well as to the purification of industrial waste containing nitrogen oxide and products from the incomplete combustion of various fuels. The purification of gases is essentially carried out during different NOx reduction and oxidation stages by performing a treatment using different layers of oxide catalysts which are applied on highly porous block supports and onto a carbon-black filter. This method also uses oxide compositions of transition metals, compounds of the perovskite and zeolite type as well as modification agents free from Pt metals. In order to neutralise poor fuel effluents, complementary reduction reagents are added such as hydrocarbons for carbonating the support and filter surfaces, or nitrogen-containing reducing agents after cooling the gases in a heat-exchanger. This invention may be used to improve the efficiency and completeness of an economical gas purification process, as well as for purifying exhaust gases from internal combustion engines in oxygen-excess conditions using a reserve of reducing reagents while warming up a cold engine.