Common protection methods for metals in cooling water systems
Thread Content
Common protection methods for metals in cooling water systems: Electrochemical protection in cooling water systems – polarizing the metal components to the corrosion-free or passivated region to provide protection； Anti-corrosion coating method: An anti-corrosion coating is applied to the heat transfer surface of metal heat exchangers to form a continuous, firmly adhered film that isolates the metal from cooling water and prevents corrosion ； Increase the pH value of the circulating aqueous solution: Metals perform better at a pH of 7–8.
Personally, I think controlling the pH level is the most effective approach
4. Improve the material: Generally, only carbon steel is coated with non-metallic coatings for corrosion protection.
Corrosion prevention in petrochemical heat exchangers has always been a topic of research in corrosion protection technology; in particular, the corrosion of the heat exchanger tube bundles affects the safe operation and production costs of the entire facility. The anti-corrosion techniques for heat exchangers need to be analyzed on a case-by-case basis. In general, water coolers and condenser tube bundles are mostly protected through a combination of surface coatings and electrochemical protection; heat exchangers, on the other hand, are primarily made of various metal materials. Of course, it is very important to properly adjust the process parameters for corrosion prevention.
Using paint is a good method, but it affects heat transfer... If temperature after heat exchange is not a concern, paint can be used; but if it is a concern, please consider selecting materials accordingly
Now, there are coatings for heat exchangers whose thermal conductivity is greater than that of carbon steel. For example, if the thermal conductivity of carbon steel is 50 W/m·K, using graphene to modify the heat exchanger coating can raise this value to around 250 W/m·K, which is comparable to the thermal conductivity of aluminum.
Thank you for your explanation. But regarding graphene... we have actually never used it before, and we are not aware of its resistance to corrosion (acids and bases). If it’s convenient for you, could you possibly provide me with some information for reference? Thank you
We all know that pure graphene cannot be used in anti-corrosion applications, as it is not possible for graphene alone to form a film that can resist the attack of corrosive agents. Taking advantage of the inherent properties of graphene, such as its high thermal conductivity and good electrical conductivity. By adding only a small amount of graphene to the coating, we can achieve the desired properties of the coating. By adding 0.3~0.5% (by solid content) of graphene to the coating, we can obtain the antistatic coating we need ； Adding 1 to 1.5 coats of coating can improve the thermal conductivity of the coating layer ； Generally, adding 1% to anti-corrosion coatings can improve their corrosion resistance. The ratios I mention here are only approximate ranges; in practice, graphene needs to be added and then tested, and it is only based on the results that we can obtain the performance indicators we need.
I see, I’ve learned a lot. Thank you for your guidance