Problem of preventing chloride ion corrosion in 316L stainless steel reactor vessels
Thread Content
The company has a setup in which hydrochloric acid is one of the reaction materials. From a reaction mechanism perspective, the chloride ions should be completely consumed (transformed entirely into “C-Cl”), but I don’t think this reaction can eliminate all the chloride ions 100%. Even if it is possible to react all the chloride ions in hydrogen chloride, what about the chloride ions contained in substances such as ferric chloride present in industrial hydrochloric acid? Meanwhile, the tolerance of stainless steel to chloride ions at 120°C is on the order of ppm. The tower is made of 316L material and has already been fully installed; it’s not possible to replace it with titanium or any other type of stainless steel. So, in this case, what are the ways to avoid corrosion? 1. Chloride ions are adsorbed using special resins before the materials enter the tower. 2. Should the tower bottom and reboiler be replaced with titanium or duplex stainless steel? 3. There should be some kind of coating that can be applied to the inside of the tower bottom to prevent contact between stainless steel and chloride ions, but I’m not sure what kind of coating would be suitable. I wonder if any other expert has another approach?
1. Resin adsorption leads to material loss; 2. Changing the material requires additional investment; 3. An acid- and alkali-resistant coating is the best solution – it requires less investment and is easy to implement
May I ask for any acid- and alkali-resistant coatings that you can recommend?
Coated with PTFE, polytetrafluoroethylene can resist strong acids, strong bases, and various organic solvents.
Stainless steel is highly susceptible to corrosion at 120°C when it contains chloride ions.
Search for acid and alkali resistant coatings; it’s not difficult to find them these days
Chloride-containing duplex steel isn’t very reliable either; our company has had similar experiences
Is it also said that spraying PTFE will cause “peeling”?
Personally, you could try a titanium nano-coating
Well, I’ll go find out! The current plan is to use enamel for corrosion protection on the tower bottom, and titanium for the tube side of the reboiler
There are not many coatings that can adhere firmly to the surface of 316L.:L