How to understand the activity of SCR catalyst?

There are different opinions on “the activity of SCR catalyst”. The accurate statement should be: the characteristic value that characterizes the comprehensive performance of the catalyst under specific operating conditions.

The calculating formula of activity: k = -AV × ln(1-η)

The following points should be noted when using the concept of SCR denitrification catalyst activity:

1. The determination of catalyst activity is related to the method of catalyst detection. The same catalyst with different detection methods, the results are not the same. The accepted method is based on the VGB-R 302H standard, and the default activity value refers to the detection value based on this standard.

2. The above activity formula is a characterization expression, not for analysis. The value of catalyst activity largely depends on the volume of the catalyst and the content of active components (for V-W-Ti catalysts, mainly vanadium content). Generally, an increase in volume will reduce the activity value, while an increase in vanadium content will increase the activity value. In engineering applications, increasing catalyst volume is very beneficial to the long-term stable operation of SCR denitration equipment, while increasing vanadium content is not necessarily a good thing, which needs to be balanced with SO₂/SO₃ conversion rate.

3. The activity of SCR catalyst is not the higher the better. In some cases, it is meaningless to compare the catalyst activity value. For example, there is no comparability in the activity of catalysts between different flue gas conditions. If the activity is used to compare the advantages and disadvantages of different brands of catalysts, it makes no sense without any restrictions.