Catalyst for treating leaked ammonia of selective catalytic reduction device and preparation method of catalyst

Abstract

The invention relates to a catalyst for treating ammonia leakage of a selective catalytic reduction device and a preparation method of the catalyst. The catalyst comprises a carrier, and an inner active coating and an outer active coating which are sequentially coated on the surface of at least part of pore channels of the carrier. The inner active coating and the outer active coating are coated on the surface of at least part of the pore channels of the catalyst carrier to form a double-active-coating structure, the inner active coating can oxidize NH3 leaked by the SCR device into NOx, and efficient and reliable purification of the NH3 leaked by the SCR device is achieved; meanwhile, the SCR catalytic active component of the outer active coating can catalyze the NOx generated by NH3 oxidation and the SCR reaction between the unpurified NOx of the SCR system and the remaining leaked NH3, and therefore efficient collaborative purification of the leaked NH3 of the SCR device and the unpurified NOx is further achieved.

Description

technical field [0001] The disclosure relates to the field of purification of diesel vehicle exhaust pollutants, in particular to a catalyst for treating ammonia leakage from a selective catalytic reduction device and a preparation method thereof. Background technique [0002] Selective catalytic reduction (SCR) technology is currently an effective method to reduce the emission level of nitrogen oxides (NOx) from diesel engines. X At the same time, it can improve the thermal efficiency of diesel engines, so it has become one of the exhaust gas treatment technologies that are widely used and can meet Euro V and Euro VI emission regulations. The principle of diesel engine SCR technology is: according to the exhaust conditions of the diesel engine, a specific amount of urea solution is sprayed into the exhaust pipe of the diesel engine; the urea solution is thermally decomposed and hydrolyzed under the action of the high-temperature exhaust of the diesel engine, and finally gen...

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Problems solved by technology

However, since the main active ingredient of this type of catalyst is noble metal platinum, not only the cost of raw materials is high, but also the effect of sulfur resistance and thermal aging resistance is poor. NH 3 Partial oxidation reactions have good selectivity, resulting in NH leakage from SCR devices under some operating conditions 3 A deep oxidation reaction occurs to generate NO, NO 2 etc., thus worsening the NOx emission of the diesel engine again

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