Analysis on the Causes of Corrosion and Perforation Accidents in Boiler Smoke Pipes
The smoke pipe of a WNS type gas boiler in a certain hotel has undergone corrosion,perforation,and leakage.It was learned from the staff that the boiler is in an alternating state of operation and standby all year round.During the shutdown period,the dosing pump also continuously adds medicine to the furnace.Water quality testing and analysis were conducted on the boiler.Although the water quality meets the standards,there is still scale generation in the boiler;The microstructure and metallographic analysis of the sample tube showed that the spheroidization of the tube was level 2;The corrosion products were tested and analyzed by X-ray energy spectrometer,and it was found that the corrosion products were mainly composed of Fe and O,with the presence of Si,Ca,Mg,Cl,S,and P components.Through the analysis of corrosion mechanism,it is concluded that the water side corrosion of the boiler flue pipe is localized electrochemical corrosion,and the types of metal corrosion are oxygen corrosion and medium concentrated alkali corrosion.Excessive dosing in water causes concentrated alkaline corrosion of the medium,ineffective deoxygenation of the boiler water results in oxygen corrosion,and Cl-in the boiler water cause small hole corrosion on the weak oxide film.The inclusion of sulfides in the steel accelerates the corrosion rate,leading to corrosion perforation of the smoke pipe.
万方数据
维普
