Abstract: According to the practical situation of the SCR denitrafication equipment of power plants, the comparative study on three ammonia slip measurement methods, including indophenol blue spectrophotometric method, Nessler’s reagent spectrophotometry method and ion selective electrode method, is conducted. The result shows that the three methods can all be applied to the measurement of ammonia slip of flue gas from the SCR denitration equipments in the power plants. Among the three methods, the ion selective electrode method has the most excellent anti-dust ability, while the Nessler’s reagent spectrophotometry method has the most stable result. The two methods are recommended for practical application.

Key words: power plant, SCR denitrification equipment, ammonia slip measurement, indophenol blue spectrophotometric method, Nessler’s reagent spectrophotometry method, ion selective electrode method