With the running time of tungsten trioxide SCR denitration catalyst going, the activity of the catalyst will be significantly reduced. The main reason is: catalyst poisoning, carbon and fly accumulation, sintering, active ingredient losing, as well as mechanical wear and destruction.

 

The main influences that the running time has on the tungsten trioxide SCR denitration catalyst are as follows:

1. From the appearance of the catalyst, with the run time extending, cellular SCR denitration catalyst pore plugging a lot, wall thinning, the color also changed caused by erosion due to the high temperature;

2. The catalyst activity is reduced, the active component vanadium lost; according to the denitration activity test, denitration performance can’t meet the requirements of coal-fired power plants after running over 30,000t;

3. With the time running, the catalyst surface compaction, agglomeration aggravating;

4. The analysis of different run-time catalyst pore structure properties showed that the flue gas fly ash can not only blocking the pores, but also affecting the internal mesoporous catalyst during operation;

5. Catalytic active component losing. The property of V=O on the catalyst surface has a significant impact on the SCR denitration, during the catalyst operation process, the V=O itself is reduced by the ammonia, and then oxidized by oxygen the flue gas, thus to cause the active ingredient losing, and result in catalyst activity decreased.

6. A large number of ash deposited on the catalyst surface with SCR denitration reaction going, the water-soluble anionic and cationic in the fly ash are one of the reasons which affect catalyst activity. The experimental results showed that the amount of fouling the catalyst surface is increased with the extension of the running time, and thus indirectly affect the amount of water-soluble ions making it appearing an increasing trend, and ultimately affect the tungsten trioxide SCR denitration catalyst activity.