A low-temperature SCR denitrification reactor with built-in pre-oxidation unit and method thereof

Abstract

The invention relates to a low-temperature SCR (selective catalytic reduction) denitration reactor with internal pre-oxidation unit and a method for denitration by the same.Flue gas is divided into two streams at a flue gas inlet, one stream of the flue gas directly enters the reactor while the other stream of the flue gas enters a pre-oxidation compartment, NO in the flue gas is oxidized into NO2 under the action of a catalytic oxidation layer, the pre-oxidized flue gas is mixed with the unoxidized flue gas, and a mole ratio of NO to NO2 in the mixed flue gas is (0.8-1.15):1.The mixed flue gas is well mixed with NH3 sprayed by a nozzle through a static mixer, and a low-temperature SCR reaction is carried out on the catalytic oxidation layer, wherein the internal temperature of the reactor is 200-350 DEG C.The low-temperature SCR reactor has the advantages that a main reaction in the reactor is changed into the rapid SCR reaction through the internal pre-oxidation unit, the reaction rate is more than ten times of a standard SCR reaction rate, denitration efficiency of a low-temperature flue gas section is greatly improved, and denitration efficiency is up to 98%.

Description

technical field [0001] The invention belongs to the technical field of flue gas denitrification, and in particular relates to a low-temperature SCR denitrification reactor with a built-in pre-oxidation unit and a method thereof. Background technique [0002] Nitrogen oxides are very harmful, can lead to photochemical pollution and acid rain, and endanger human health. Selective Catalytic Reduction (SCR) technology is to use a suitable reducing agent to reduce NOx in the flue gas to N under the action of a catalyst. 2 and water to reduce the hazards of nitrogen oxides. 4NH is mainly produced in the SCR reactors currently used on a large scale 3 +4NO+O 2 →4N 2 +6H 2 The chemical reaction of O, under the action of a vanadium-titanium system catalyst, requires a reaction temperature above 350°C to achieve a high denitration efficiency, and the denitration effect is poor under low temperature and complex working conditions. Contents of the invention [0003] Aiming at the...

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Problems solved by technology

4NH is mainly produced in SCR reactors currently used on a large scale 3 +4NO+O 2 →4N 2 +6H 2 The chemical reaction of O, under the action of a vanadium-titanium system catalyst, requires a reaction temperature above 350°C to achieve a high denitrification efficiency, and the denitrification effect is poor under low temperature and complex working conditions

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