Effects of Trace Impurities in Coal-Derived Liquid Fuels on Deposition and Accelerated High-Temperature Corrosion of Cast Superalloys

摘要

This is a review of work describing effects of trace metal impurities in coal-derived liquids on deposition, high temperature corrosion, and fouling. Alloys were burner rig tested from 800 to 1100 exp 0 C, and corrosion was evaluated as a function of potential impurities. Actual and doped fuel tests were used to define an empirical life prediction equation. An evaluation of inhibitors to reduce or eliminate accelerated corrosion was made. Barium and strontium were found to limit attack. Intermittent application of the inhibitors or silicon additions were found to be effective techniques for controlling deposition without losing the inhibitor benefits. A computer program was used to predict the dew points and compositions of deposits. These predictions were confirmed in deposition tests. The potential for such deposits to plug cooling holes of turbine airfoils was evaluated. Tests indicated that, while a potential problem exists, it strongly depended on minor impurity variations. (ERA citation 06:033509)