Katalytische Kohlenstoffmonoxidoxidation in Stahlwerksabgasen

Translated title of the contribution: Catalytic carbon monoxide oxidation of exhaust gases from steel industry

Research output: ThesisMaster's Thesis

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Abstract

The carbon monoxide oxidation catalysis in sinter plant exhaust gas implies high potential resource and energy saving aspects. Challenging properties of sinter plant exhaust gas require catalysts with particular stability characteristics. For this purpose the perovskite-type oxide lanthanum cobaltate in combination with zirconia support was examined in this study. The active component lanthanum cobaltate shows comparable activity to conventional platinum-based catalysts under common exhaust gas conditions. Moreover, zirconia support causes fine distribution of the active sites on the carrier. During test phase 1 the catalytic activity was analysed in the absence of sulphur dioxide. For lanthanum cobaltate/zirconia (calcination at 700 °C) more than 90 % conversion of carbon monoxide at 260 °C could be achieved. Based on promising results, sulphur dioxide influence was investigated within phase 2. Initially, high activity for lanthanum cobaltate/zirconia could be determined in spite of sulphur dioxide presence. After several test runs in instationary conditions, e.g. temperature variation, all examined catalysts were deactivated as a consequence of sulphur dioxide/water exposition. These results correspond with most references found in literature, stating that deactivation is the consequence of sulphur dioxide chemisorption on lanthanum cobaltate or cobalt oxide at higher temperatures (> 300 °C). Sulphuric acid formation is expected to be responsible for catalyst deactivation in sinter plant exhaust conditions. Furthermore, sulphuric acid condensation is influenced deeply by surface pore size distribution. Without intermediate removal of sulphuric acid by catalyst washing, long-term sulphur dioxide stability could not be clearly determined. Manifold catalyst deactivation mechanisms in sinter plant conditions, as indicated in this work, outline challenges for further investigations. Perovskite-type oxides provide a large pool of properties, promising to find sulphur dioxide-stable catalysts.
Translated title of the contributionCatalytic carbon monoxide oxidation of exhaust gases from steel industry
Original languageGerman
QualificationDipl.-Ing.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Weiß, Christian, Supervisor (internal)
Award date15 Dec 2017
Publication statusPublished - 2017

Bibliographical note

embargoed until 30-10-2022

Keywords

  • oxidation catalysis
  • carbon monoxide
  • sulphur dioxide
  • lanthanum cobaltate
  • sinter exhaust gas

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