CORROSION FOR CHEMICAL ENGINEERS

In the previous article the basic principles of corrosion were considered with particular reference to immersed conditions of attack and it was shown that corrosion resulted from the interaction of the metal and its environment and occurred by a galvanic cell mechanism. It follows, therefore, that anodic attack may be prevented by factors which may be either related to the metal or the environment. It is the purpose of this article to apply the theoretical principles of corrosion to practical problems and to consider in particular how corrosion can frequently be avoided in the earliest stages by attention to design. No particular process will be considered but rather the effect of the metal, method of construction, shape, velocity of flow of the liquid, dissimilar metals in contact, etc., on the possibility of corrosion occurring. Although there are certain basic principles in designing to avoid corrosion, it should be emphasised that this must be followed by pilot‐plant testing, as only in this way can t...