In situ corrosion testing of various nickel alloys at Måbjerg waste incineration plant

Abstract

The majority of waste in Denmark is disposed via waste to energy (WTE) incineration plants which are fabricated from carbon steel. However, due to the increasing corrosiveness of waste over the years, more corrosion resistant alloys are required. In Denmark, Inconel 625 (UNSN06625) is the weld overlay material currently being used to give improved corrosion resistance. In order to assess the use of alternative nickel alloys, test panels have been manufactured and inserted into Måbjerg waste incineration plant. Inconel 625 as a 50% weld overlay, two layered weld overlay and as a spiral weld overlay was exposed. Other nickel materials exposed were weld overlay Alloy 686, Alloy 50 and Sumitomo Super 625 coextruded tube. Exposure has been undertaken from 2003 to 2009 in the first pass and 2005–2009 in the second pass, and sections have been removed and investigated during this period. The composition of the deposits from the exposed waterwall panels was also analysed each time sections were removed. This paper will compare the various nickel alloys in the two areas and assess the results of the long‐term testing project.

Field exposure of FeCrAl model alloys in a waste‐fired boiler at 600°C: The influence of Cr and Si on the corrosion behaviour

“…The reference material used was a 16Mo3 sample ring, overwelded with Inconel 625. This has been exposed various times in similar field exposures (biomass‐ and waste‐fired boilers) due to its exceptionally high corrosion resistance and can therefore be used as a measure of the corrosivity of the present conditions. A disadvantage with the overweld is that the sample ring thickness is not even and accurate thickness measurements for calculation of material loss was therefore not possible.…”

High Temperature Corrosion Studies of a Zirconia Coating: Implications for Waste-to-Energy (WTE) Plants

“…In the last decades, the use of nickel-based superalloy claddings has found widespread application. In particular, Inconel 625 is a widely used material, due to its good corrosion resistance with lifetimes of up to 20 years [6][7][8][9]. With a thickness of several millimeters, these claddings are very cost intensive.…”

Ni, Cr, and Fe surfaces corroded by molten ZnCl2

“…Along with these potentials of molten ZnCl 2 are challenges, such as the corrosion of structure and container alloys containing the elements Ni, Cr, or/and Fe by an eutectic of molten ZnCl 2 , the pollution of molten salts, and so on. In addition, in incineration plants, which are considered as a valid and efficient technology to treat municipal solid wastes, molten ZnCl 2 is one of the most common impurities in residues and can corrode boiler superheater tubes used in incinerators crucially …”