On the basis of conventional inspection method for single SCR catalyst element activity in laboratory

the NOxand ammonia escape concentration at inlet and outlet of the SCR device was measured during field performance test

by taking the multi-layer cascade catalyst in the SCR reactor as the research object.The de-NOxefficiency-ammonia slip method was used to evaluate the macroscopic SCR potential with the deNOxefficiency and ammonia slip measured from the field SCR performance test with the actual operating NH3/NO molar ratio less than 1.0.Field test results of 11 units show that the relative deviation of SCR potential in each unit with different NH3/NO molar ratios at full load ranges from-2.0%to 1.8%

indicating the field performance test data have well repeatability

which can reflect and evaluate the SCR device performance.Finally

by taking a down-fired 600 MW unit boiler as the example

the SCR performance degradation function over time was regressed from the SCR potential measured at different time and then used to adding or replacing the catalyst layer.