The present study has been conducted to investigate the corrosion and scale formation rates of CS-A106 and 5Cr-A182 exposed to different acid concentrations and varying amounts of sulfur compounds. The experiments were designed to determine the effect of time, temperature and acid concentration on the formation and retention of sulfide films formed on the steel surface. A hot oil flow loop “Flow Through Mini Autoclave” was used to conduct experiments forming sulfide scales at different acid concentrations varying from 0.04 to 4. Temperature of these experiments was varied from a low temperature (450°F) to a high temperature (700°F). Tests were conducted for a short period of 3 hr to a long period of 96 hr.
It was observed that sulfide scales protect steel surface from being corroded once they formed on the steel. Amount of scale accumulated on the steel increased with time but the protectiveness of the scale was highly reliant on the time of exposure, acid concentration and temperature. Sulfide scales were subjected to cracking and it reduced the adherence of scale to steel surface. Sulfide scales were not 100% dense and SEM pictures showed porous scales formed in all experiments.