Corrosion protection in dechlorination process
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This post was last edited by sunjl1981 on 2013-1-6 at 23:55. The pipes in the company’s dechlorination process are suffering from severe corrosion, and I would like to know what causes this. Is it related to the amount of alkali added and the amount of sodium sulfite? # ， ， &
Complex medium: contains brine, hypochlorites, chlorates, as well as acids and bases, along with high temperatures. The key is to select good materials, and then ensure stable operation.
If ordinary carbon steel is used, the main issue is an excessive amount of sodium sulfite being added. Since sodium sulfite is a common deoxidizing agent that can effectively remove rust, it is often used for deoxidizing boilers. Meanwhile, the presence of sodium chloride in the system can lead to oxygen-induced corrosion, especially at the interfaces in contact with air. The rust resulting from this oxygen-induced corrosion is quickly removed by sodium sulfite, exposing a new surface; this new surface is then rapidly oxidized again, and this cycle repeats itself, resulting in severe corrosion of the system’s pipes
Question for Floor 3: The presence of sodium chloride in the system can cause oxygen-induced corrosion. What does that mean? Has electrochemical corrosion occurred? Could you be more specific? Is there any way to deal with this?
The medium conditions in the dechlorination process are complex and highly corrosive; when selecting materials, the following aspects should be taken into account: Dechlorination tower, jet pump (chlorine water circulation pump), dechlorination brackish water pump: titanium； CPVC is a better choice for pipes carrying dechlorinated brine, chlorine water, and high-purity hydrochloric acid ； Stainless steel for sodium sulfite pipelines and caustic soda pipelines ； The chlorine water circulation tank is lined with natural rubber; corrosion protection must be adequate, and electric spark testing must pass, as there is a possibility of hydrogen generation ； Gas exhaust fan pipeline: UPVC ；