Sulphur Dew-Point Corrosion in Exhaust Gases

Sulphur dew-point corrosion continues to be an important problem in steam-power stations and some gas-turbine applications. A series of corrosion tests is described in which it was found that the effects of this type of corrosion can be minimized by (a) use of certain corrosion-resistant alloys such as Hastelloy C, Carpenter No. 20, or Type 316 stainless steel; (b) the use of low-sulphur fuels; or (c) the maintenance of surface temperatures above the acid-water dew point. The tests indicate that none of the presently available coating materials can provide adequate low-temperature corrosion protection for heat-exchanger surfaces or compressor blading.