Using the newly developed automatic potential controller, anodic protection can be used to prevent a severe corrosion problem in the manufacture of petroleum sulfonates. Corrosion was a major problem in a mild steel oleum storage tank and in a 304 stainless steel sulfonic acid neutralization vessel.
Laboratory studies of anodic polarization curves showed that anodic protection was theoretically possible in both these systems. A potential controller, suitable platinum cathode and reference electrode were designed and successfully installed on each vessel. A solid reference electrode was necessary since the usual calomel or copper sulfate reference electrodes were not suited to the system of high temperature and extreme agitation.
The effectiveness of anodic protection was measured in terms of (1) reduction in iron concentration throughout the process; (2) improved quality of product due to absence of colored iron salts; (3) increased productivity of plant due to more rapid product hydrocarbon separation due to the absence of iron soaps. This equipment has continuously and automatically controlled corrosion in a sulfonation plant for one year. 2.4.2
