INHIBITION OF HYDROGEN ABSORPTION BY STEELS IN WET HYDROGEN-SULFIDE REFINERY ENVIRONMENTS

Hydrogen permeation and polarization measurements were used to investigate hydrogen absorption by pressure vessel steels in refinery environments containing hydrogen sulfide (H2S), ammonia (NH3), and cyanide (CN-). The severity of these environments is determined by the concentrations of bisulfide (HS-) and CN-. Corrosion rates and hydrogen absorption efficiencies were found to depend on H2S and NH3 concentration in the pH region where HS- was the dominant protonic species. Effects of chemical additives on corrosion and hydrogen absorption were examined. Of the chemicals tested, diamines with long carbon (C) chains were the most effective in reducing the corrosion rate and hydrogen absorption.