METHOD AND SYSTEM FOR REMOVING NITROGENOUS COMPOUNDS FROM FLUE GAS USING CLOTH FILTER BAGS AND SCR CATALYST Russian patent published in 2021 - IPC B01D53/86 B01D53/56 

FIELD: exhaust gas purification.

SUBSTANCE: present invention relates to a method and system for the recovery of emission solid particles and nitrogen oxides (NOx) from waste gases and flue gases. Flue gas is passed through one or more cloth filter bags catalyzed by a selective catalytic reduction catalyst of nitrogen oxides in the presence of ammonia added to flue gas either as such or in the form of its precursor. Waste gas containing nitrogen dioxide is introduced into flue gas upstream of one or more cloth filter bags. Waste gas containing nitrogen dioxide is provided by catalytic oxidation of ammonia or its precursor by oxygen-containing atmosphere to waste gas containing nitrogen monoxide and oxygen in the presence of an oxidation catalyst. Next, waste gas is cooled to an ambient temperature from -20°C to 40°C. In cooled waste gas, nitrogen monoxide is oxidized to waste gas containing nitrogen dioxide. Waste gas containing nitrogen dioxide is introduced into flue gas in the amount that leads to the fact that from 45 to 55 vol.% of nitrogen oxides are nitrogen dioxide at the entrance to the selective catalytic reduction catalyst of nitrogen oxides.

EFFECT: increasing the efficiency of SCR catalyst at a gas temperature below 250°C.

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