The reasons for the shedding of the cone of the desulfurization tower in the raw material sintering plant was investigated by metallography,scanning electron microscope and x-ray diffraction.The results showed that the water vapor in the flue gas forms condensed water on the inner wall of the cone,and the corrosive components in the flue gas or after the flue gas is oxidized by ClO2 gas dissolve into the condensed water to form electrolyte.The electrolyte penetrates into the desulfurization ash which is attached to the inner wall of the cone of the desulfurization tower,causing electrochemical corrosion to the inner wall of the steel plate of the desulfurization tower;Since the material of the desulfurization tower cone is Q235 plain carbon steel,it has no corrosion resistance,resulting in the formation of thicker corrosion products on the inner wall of the steel plate of the cone of the desulfurization tower,together with the desulfurization ash form scaling on the inner wall of the desulfurization tower,and further crevice corrosion occurs.The Clˉ generated by the reaction of the flue gas and the oxidant ClO2 gas,together with the Clˉ in the flue gas,accelerates the corrosion process of the desulfurization tower.Eventually,the steel plate of the cone is continuously corroded and thinned,resulting in a decrease in its load-bearing capacity.When the load-bearing capacity is lower than the weight of the cone itself,the cone breaks and falls off.
desulfurization and denitrificationdesulfurization towerFOSS processelectrochemical corrosioncrevice corrosion
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