Scr catalyst for removal of nitrogen oxides

Abstract

The present invention provides for catalysts for selective catalytic reduction of nitrogen oxides. The catalysts comprise metal oxide supporters, vanadium, an active material, and antimony, a promoter that acts as a catalyst for reduction of nitrogen oxides, and at the same time, can promote higher sulfur poisoning resistance and low temperature catalytic activity. The amount of antimony of the catalysts is preferably 0.5-7 wt %.

Description

TECHNICAL FIELD[0001]The present invention relates to catalysts for selective reduction of nitrogen oxides, and more particularly to catalysts for removal of nitrogen oxides that have enhancing effects on the reduction activity of nitrogen oxides at low temperatures and on the sulfur poisoning resistance.BACKGROUND ART[0002]Nitrogen oxides (NOx) are usually produced when fuels are combusted, and are exhausted from moving sources such as a motor vehicle and fixed sources such as a power plant or an incinerator. These nitrogen compounds are identified as the major causes of acid rain and smog formation. Since environmental protection regulations have become stricter recently, more studies are being carried out, in response, in order to reduce nitrogen compounds through catalysts.[0003]As a method of removing nitrogen compounds that were emitted from fixed sources, selective catalytic reduction (SCR) device that uses vanadium oxides (V2O5) as active materials impregnated on a titanium ...

AI Technical Summary

Benefits of technology

[0012]The present invention provides for catalysts for the reduction of nitrogen oxides that are impregnated in to supporters and contain vanadium as an active material and antimony as a promoter that promote reduction of nitrogen oxides at low temperatures and increase sulfur poisoning resistance.

[0016]As mentioned above in the conventional arts, nitrogen oxides can be reduced to harmless nitrogen and water by using a reductant. Catalysts for the reduction of nitrogen oxides are used and each of these catalysts comprise a supporter, an active material and a promoter which reduces sulfur poisoning and enhancing low temperature catalytic activity.

[0020]According to the present invention, antimony is added to promote the reactivity at low temperatures and the sulfur poisoning resistance. Preferably, 0.5-6 wt. % of antimony is added. By the addition of antimony as a promoter, the addition amount of vanadium can be reduced, and thus, the sulfur poisoning resistance can be reduced. Preferably, 1-3 wt. % of vanadium is added.

Problems solved by technology

The produced ammonium bisulfate salts are imbedded into the surfaces of the catalysts, thereby interfering with the reduction reaction.

As a result, as the amount of unreacted ammonia increases, formation of sulfur trioxides (SO3) is promoted, thereby accelerating the sulfur poisoning, which eventually shorten the life of the catalysts.

%, the increase in the price of catalysts is unavoidable.

A conventional art uses a TiO2 supporter impregnated with vanadium sulfate (VSO4), vanadyl sulfate (VO SO4) and the like, and is reacted at the range of temperatures at 300-520° C. However, the problem of the previously-explained sulfur poisoning also arises in this case due to the usage of vanadium.

However, not only the problem of the sulfur poisoning from vanadium oxides still exists, but also, the previously-mentioned high cost problem due to the usage of tungsten oxides are accompanied.

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