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MM: Fachverband Metall- und Materialphysik

MM 4: Structural Materials

MM 4.7: Vortrag

Montag, 5. September 2022, 12:00–12:15, H46

Sulphation kinetics of chloride particles, corrosion potential and effect of reactive additives — •Sebastian Pentz and Ferdinand Haider — Universität Augsburg, Institut für Physik, 86135 Augsburg

Chlorine induced high temperature corrosion leads to massive problems especially in waste-to-energy-plants, but also in biomass combustion. During the combustion process chloride containing particles are released and deposited on heat exchanger surfaces. There chlorides get converted into sulphates with a release of chlorine species which then lead to severe corrosion. In laboratory experiments we study the conversion kinetics under various conditions like temperature, particle size or gas composition. Both the sulphation reaction and the rate of subsequent corrosion show an Arrhenius dependency on temperature, a linear dependence on time, on particle surface and on partial pressure of SO2. The addition of reactive additives can strongly influence this reaction and consequently the release of chlorine species: Adding iron oxide (e.g. Fe₂O₃) results in a strong acceleration of the sulphation process due to catalysis of the reaction from SO₂ to SO₃. On the other hand, a reduction of the sulphur content in the reaction atmosphere by desulphurising species like calcium oxide slows down the sulphation reaction and reduces the amount of released chlorine compounds.In lab experiments, chlorides (mixed with additives) are applied to 16Mo3 steel samples and exposed to a flowing reaction atmosphere in a tube furnace.Support by Federal Ministry for Economic Affairs and Climate Action on the basis of a decision by the German Bundestag.