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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Alkali attack on coal gasifier refractory lining

Lee, Kyoung-Ho January 1988 (has links)
For a given coal gasification atmosphere, the reactions between fired alumina-chromia solid solution refractories and alkali (sodium and potassium) with and without sulfur at varying alkali concentrations were thermodynamically calculated using the SOLGASMIX-PV computer program and the results were experimentally confirmed. In addition, the kinetics of alkali diffusion into the refractory were experimentally determined as a function of time and temperature. The results, both experimental and theoretical, show formation of alkali-aluminate (Na₂O⋅Al₂O₃, K₂O⋅Al₂O₃) and β-alumina (Na₂O⋅11Al₂O₃, K₂O⋅11A₂O₃) compounds with formation of several metastable alkali compounds in a coal gasification environment. Sulfur did not appear to affect the reaction products. Alkali distribution into the alumina-chrome refractory is rapid and the formation of the Na₂O⋅Al₂O/K₂O⋅Al₂O₃ compounds cause large volume expansion from the reaction surface which causes poor thermal shock resistance and eventual refractory failure. The hot face of an alumina-chrome refractory in service in an alkali environment will be prone to failure by alkali attack. / Master of Science

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