China is energy consuming country which is taking coal as the primary energy. In the combustion process of coal, it will produce a large amount of sulfur oxides (SOx) and nitrogen oxides (NOx), where industrial and mining coal combustion NOx emissions account for a very large proportion, about 70%. SCR is not only the most widely used currently, but also the most mature technology for stationary sources denitration technology. Denitration catalyst takes the key part of SCR technology, which directly determines the denitration efficiency. This article will examine the SCR denitration catalyst containing tungsten trioxide affected by sulfur dioxide.

 

The raw materials of tungsten trioxide denitration catalyst include: ammonium metavanadate, hydrated ammonium tungstate, ammonium molybdate, oxalic acid, anatase titanium dioxide, forming agent and additives. 

 

Experimental part:

1. when the temperature is 350 ℃, inlet the sulfur dioxide, we observe that the denitration efficiency is falling and then raising, after a certain reaction time, the activity of WO₃ denitration catalysts is little less than that without sulfur dioxide;

2. When the sulfur dioxide gas concentration reaches a certain value, the denitration catalyst activity was inhibited in a certain period of time, but with the reaction continues, the inhibition will be weaker and weaker, and will eventually return to the state of non-sulfur dioxide; when the concentration of sulfur dioxide reaches to 1000ppm, the inhibition will be more evident.

 

Therefore, we can see: weakly inhibits the sulfur dioxide has on catalyst activity; low sulfur dioxide concentration has little effect on catalyst, but high sulfur dioxide concentration will cause a greater inhibition. This shows that the SCR denitration catalyst containing tungsten trioxide has a strong anti-sulfur dioxide poisoning feature.