2nd Year Comparison of Superheater Metal Wastage Rates Utilizing Various Boiler Tube Alloys in a Waste-to-Energy Facility

The SEMASS Resource Recovery Facility (SEMASS) is a processed refuse fuel (PRF) waste-to-energy plant serving Southeastern Massachusetts. The plant consists of three 1000 ton per day boilers that generate steam at 765 F and 650 psig for use in a steam turbine/generator set. Over the past several years there have been a series of plant improvements made in order to achieve compliance with the MACT emission standards. Unfortunately, metal wastage rates due to fire side corrosion of pressure containing components, have increased significantly during this same time period. In an attempt to reduce overall maintenance costs and unscheduled down time due to tube failures, a test of various alloy tube materials was undertaken in 2001 (see NAWTEC#10 paper-1021) in the primary superheater section of boiler #1. The materials tested were SA213-T22 (original spec.), SA213-T22-Heavy Wall, SA213-TP310H, SB-423 Incoloy 825, and Inconel 625 spiral weld overlay of SA213-T22 base material. This paper will summarize the results of the second year of testing including wastage rate tables and annualized costs for the various tube materials.