A study on preparation of sulfur-iron compounds and their electrochemical and hydrogen barrier properties

Abstract

Corrosion and hydrogen damage cause problems to oil and gas industry equipment. FeS (sulfur-iron) compounds generated by H2S causes surface corrosion and covers the surfaces of the equipment where the extent of corrosion and hydrogen damage are influenced by these compounds. Different types of FeS compounds have different crystal structures, and there by influence their corrosion and hydrogen resistance. In this paper, single-structure pyrrhotite and pyrite were synthesized by hydrothermal method, which was controlled by controlling the temperature and Fe, S ratio. Their structures are hexagonal sheet and polyhedron respectively. The interfacial properties and hydrogen barrier properties of FeS were tested and the results show that pyrrhotite possesses anion selectivity. The electrochemistry shows low impedance modulus and high corrosion current density, which indicates low corrosion resistance. Pyrrhotite has the lowest hydrogen permeation current density and has good inhibition of hydrogen permeation ability. For the high impedance modulus and low corrosion current density pyrite possesses cation selective, which shows strong resistance to corrosion. However, its hydrogen permeation current density is high and hydrogen blocking effect is weak.