Abstract: Ammonia slip is the key parameter of the SCR denitrification from coal-fired boiler flue gas.On the basis of a large sample sizes study on the application sta-tus of ammonia slip online monitoring of SCR denitrifica-tion from coal-fired boiler flue gas,application situation, ap-plication effect,typical problem were systematic summarized and analyzed, and some countermeasures were proposed, which can be used for further reference.

Key words: de-NOx, ammonia slip, online monitor? ing, application status