Abstract
Fe++ and Fe+++ ion are most usually found in the solutions of acid cleaning of any equipments. Besides, when petroleum reformer is cleaned with acids, a large amount of H2S is evolved on dissolution of FeS scale and the acid solutions are saturated with H2S.
The effect of inhibition was examined under the co-existence of these materials with four commercial inhibitors, and the following results were obtained.
1) The effect of H2S on the corrosion of steel somewhat differed according to the kind of inhibitors, although H2S was generally considered to increase the corrosion rate.
2) Fe++ ion scarcely affected the corrosion rate.
3) Fe+++ ion, in the presence of H2S, was reduced to Fe++ and did not accelerate the corrosion rate so remarkably.
Data in some actual field were also shown.
