Corrosion of engineering alloys in simulated eastern oil shale retorting environments

Abstract

Eastern United States oil shales usually contain sulfur levels considerably higher than those encountered in their Western counterparts. Because the emphasis in the development of Eastern oil shale retorting technologies is rather recent, very little is known about the requirements for materials of construction for various high temperature components. In this investigation, engineering alloys, including carbon steel, 410 ss, and 304 ss, have been exposed in the laboratory to environments approximating those encountered in indirectly heated Eastern oil shale retorts. These included temperatures in the neighborhood of 455 °C (850 °F) and gases with typically 1 pct H2, 1 pct H2S, and 10 pct H2O. Special runs were also made where samples were packed in spent shale to determine how such contact would affect performance. The corrosion rates and the corrosion products observed in the laboratory experiments resembled the trends and features encountered in pilot plant retort coupons exposed to comparable environment and temperature conditions. These experiments were extended to exposure times exceeding those of the longest retort alloy tests. The results are used to evaluate mechanisms of alloy deterioration and to aid in providing criteria for the selection of materials of construction.