Abstract: Aiming at the issue of high ammonia consumption in one 600-MW unit in Fujian Province, the SCR velocity field and ammonia slip are measured as theoretical evidences to reduce the ammonia slip volume. The flue gas velocity and ammonia slip at the SCR inlet and outlet values are measured by using micro-manometer and gas analyzer and then the measurement data are post-processed by using Tecplot. The analysis results show that the SCR inlet arrangement significantly affects the flue gas velocity distribution while the flue gas velocity field has great impacts on the ammonia slipping. The higher the NO_x capture efficiency, the higher ammonia slip rate will be reached. The SCR outlet flue gas velocity field and the ammonia slip rate indirectly reflect the activity as well as the plugging of catalysts. Moreover, piping wearing may occur due to the existence of high velocity area at the outlet.

Key words: thermal power plant, flue gas denitration, SCR, ammonia slip