Material issues related to coking wastewater
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Recently, I encountered a project for treating coking wastewater. Due to the presence of corrosive ions such as Cl in this wastewater, careful consideration was required when selecting the appropriate materials. But there is a wastewater preheater, and CS is generally chosen as the material for both the hot and cold sides. Is carbon steel more susceptible to chloride corrosion than stainless steel? I appreciate your guidance.
Carbon steel is not as resistant to Cl corrosion as stainless steel; even with just CL salts, its service life is likely to be short, so titanium is the best choice.
Theoretically, that’s the case. As far as I know, there are usually many CS agents on site, which is why I’m confused.
Looking at the components and concentrations, moreover, the materials chosen in the designs developed by some companies may not be appropriate, especially those from small environmental protection firms. I encountered problems with a waste brine treatment project – all the main equipment had to be replaced
Titanium is too expensive; why not try our 711 inorganic anti-corrosion coating?
It is likely due to cost-saving considerations; generally, for such preheaters, the tube side uses 2205 material, while the shell side uses 304 or 316 material
It’s mainly because special materials are too expensive. 304 is prone to pitting and leakage in such applications; repairing it after 1-2 years is troublesome, and the cost of scrapping it is too high. For carbon steel, it lasts only 1-2 years before it needs to be discarded.