Corrosion and Degradation of Materials in the Synthane Coal-Gasification Pilot Plant

摘要

Corrosion monitoring of materials was conducted in the operating environments of the Synthane coal gasification pilot plant between 1976 and 1978. Metal and refractory specimens were exposed in the gasifier vessel in two test locations (fluidized bed, freeboard). Metal coupons only were exposed in the gasifier char cooler (freeboard) and four test locations in the quench system (vapor and liquid phases). Exposure times under operating conditions were 181 to 782 h. In two gasifier test locations (600 psig, 1284 exp 0 F and 1434 exp 0 F), the performance of nickel-base alloys with >20 wt % Cr, 40 to 46 wt % Ni, and 3 to 9.1 wt % Mo was consistently better than for other test alloys. Equivalent linear corrosion rates for these better alloys were < 20 mpy (782 h) with Montana Rosebud coal as feedstock; however, with Illinois No. 6 coal the linear rates were >20 mpy but <75 mpy (181 h). IN-600 (76.5 wt % Ni, 15.8 wt % Cr) was found unsuitable for gasifier internal application. All refractories tested in the two gasifier test locations (600 psig, 1284 exp 0 F and 1434 exp 0 F), with the exception of silicon nitride, were not greatly affected during either exposure period. The better materials were monolithic refractories with 5 to 30% porosity and 50 to 60% alumina content. Corrosion monitoring of metals in the gasifier char cooler freeboard (600 psig, 800 exp 0 F) showed that Type 304 was more resistant to corrosion attack than Type 410 and carbon steel. (ERA citation 07:048997)