In view of phenomena concerning gas and air ducts’ vibration as well as vibration due to fans’ fouling in Niangziguan Power Plant

causes leading to occurance of said phenomena have been analysed through frequency spectrum test and hot state test. It is considered that the main causes leading to said vibration are: out-of-matching between forced draft fan and the resistance of draft air pipeline

bad quality of fixing the air ducts

and ash deposition on the bladed disc of induced draft fan

etc. After retrofitting the forced draft fan as 5-53 type high-effective one

and the induced draft fan as 4-6B type fan with straight-plate blades

as well as consolidating the gas duct

the said vibration problems have been solved.