Regensburg 2019 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 39: Structural Materials (Steels, light-weight materials, high-temperature materials)
MM 39.2: Talk
Thursday, April 4, 2019, 15:15–15:30, H45
High Temperature Chlorine Corrosion - Influence of additives on alkali-capture and the effect on corrosion in waste to energy plants — •Sebastian Pentz1, Daniel Ott1, Ferdinand Haider1, and Ragnar Warnecke2 — 1Universität Augsburg, Institut für Physik, 86159 Augsburg — 2Gemeinschaftskraftwerk Schweinfurt GmbH, 97424 Schweinfurt
High temperature corrosion especially in waste-to-energy-plants leads to massive problems. At prevalent temperatures around 400∘C-600∘C corrosion is mainly chlorine induced. Responsible for the supply of chlorine at heat exchangers like superheaters or boiler walls is in majority a local release of chlorine through sulfation of solid alkali chlorides out of deposits on the steel parts. This reaction requires an atmosphere containing SO2, H2O, O2 and releases HCl/Cl2.Due to additive addition in the incinerator one tries to minimize this deposit built up. While encapturing alkalies by additives the formation of alkali chlorides is reduced which leads to less condensation of gaseous alkali chlorides on colder steel parts and therefore a reduction of chlorine enriched deposits. One possible material class for alkali-capture seem to be aluminum silicates. The interstratification of alkalies out of alkali chlorides into aluminium silicates leads to a release of chlorine. The corrosive attack of the steel through chlorine strongly depends on the released chlorine species. HCl is much less critical than Cl2. Principles of the reaction conditions in waste-to-energy-plants are shown and laboratory experiments regarding the additive influence on kinetics of sulfation reactions and the corresponding chlorine attack are presented.