Abstract
Economical, effective and relatively easy to handle, hydrochloric acid is being widely used as a solvent for chemical cleaning of refinery equipment. Inhibitors must be added to retard corrosion during cleaning operations, but these inhibitors must not prevent dissolution of the scale to be removed. Practical temperature ranges for cleaning are given. The corrosion rate increases exponentially with temperature and with acid concentration. The corrosion .rates of various metals in 5 percent inhibited hydrochloric acid are given. The influence of inhibitors on the rates of dissolution of iron oxides and sulfides are shown.
Four typical cases of corrosion occurring during acid cleaning are discussed with special safety precautions that should be observed during cleaning operations. The influence of commonly present substances such as hydrogen sulfide is shown to increase the rate of corrosion. 5.9.2
