Analysis of a Corroded Stainless Steel Recuperator Used on a Glass Melting Furnace

摘要

A recuperator installed on a natural gas-fired glass melting furnace recovered heat from flue gases to preheat combustion air for the gas burner. The recuperator, which was constructed of type 321 stainless steel, supplied combustion air at about 500 exp 0 C for about 5760 h (eight months). Although some corrosion of the partition wall in contact with the flue gases was noted during the early weeks of operation, the recuperator continued to supply preheated air at near design temperature throughout the campaign. The partition wall had a 1.5-mm-thick corrosion product consisting of oxides and possible sulfides, and the alloy exhibited a region of grain boundary attack. The thickness of the corrosion product far exceeded that predicted by assuming that only oxidation occurred at the indicated temperature of 650 exp 0 C. It was concluded that accelerated corrosion was caused by a sulfidation-oxidation mechanism resulting from carry-over of a sulfur-bearing compound from the glass batch and the fuel. (ERA citation 06:006209)