Superheater Life With Stainless, Inconel, and Carbon Steel Alloys at the Maine Energy Recovery Company

The Maine Energy Recovery Company is a refuse derived fuel (RDF) waste to energy facility that began commercial operation in 1987. The facility consists of an RDF production operation, two B&W boilers which produce 210,000 lb/hr of steam at 650 psig/750F with a design Furnace Exit Gas Temperature of 1700 F, and a 22 MW steam turbine generator. Since startup, the facility has suffered fireside erosion/corrosion of the waterwalls, superheater, and generator bank hot side sections. Through the years, Maine Energy has made various operational and design changes in order to improve combustion and overall boiler availability. While combustion has improved as evidenced by improved emissions, reduced supplemental fuel usage, and lower ash production, superheater availability has suffered. At the same time reliability of the waterwall and generating bank components have improved. This paper will present a history of Maine Energy’s efforts to improve its superheater availability including a summary of the tube wastage rates for various superheater alloys, as well as Maine Energy’s plans for its superheaters.