Catalytic oxidation of NOx/SOx in flue gases with atmospheric oxygen as the oxidation reagent

A combined system for catalytic oxidation and wet-scrubbing of simultaneously both nitrogen oxides (NOx) and sulphur oxides (SOx) from a flue gas, and for manufacturing fertilisers comprising:

• a) An air separation unit for separating atmospheric oxygen from air and thereby producing an air stream substantially enriched with atmospheric oxygen for oxidation of NOx and SOx;
• b) An adsorption and oxidation reactor containing a dry oxidation catalyst or an adsorbing dispersion containing the oxidation catalyst, and designed to receive the air stream substantially enriched with atmospheric oxygen and a flue gas stream containing NOx and SOx, to adsorb said streamed gases, and then to carry out the catalytic oxidation of said NOx and SOx by said oxygen to yield nitric and sulphuric acids;
• c) A separator and reactor control unit for separation of products and liquids and controlling said catalytic oxidation and wet-scrubbing;
• and
• d) A vessel containing gas or liquid ammonia, connected to said adsorption and oxidation reactor or to said separator and reactor control unit, and having an inlet streaming said ammonia into the adsorption and oxidation reactor or into the separator and reactor control unit to react with the nitric and sulphuric acids and to yield ammonium nitrate and ammonium sulphate fertilisers, thereby wet-scrubbing NOx and SOx from the flue gas and producing said fertilisers.