Effects of used bed materials on char gasification: Investigating the role of element migration using online alkali measurementsShow others and affiliations
2022 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 238, article id 107491Article in journal (Refereed) Published
Abstract [en]
Online alkali measurements using surface ionization are employed to study alkali release during heating of used industrial fluidized bed materials and gasification of biomass-based char and bed material mixtures. The alkali release from the bed materials starts at 820 °C and increases with temperature, the time a bed material has experienced in an industrial process, and in the presence of CO2. Online alkali measurement during heating of char mixed with used bed material shows significant alkali uptake by the char. Complementary SEM-EDS studies confirm the alkali results and indicate that other important inorganic elements including Si, Mg, and Ca also migrate from the bed material to the char. The migration of elements initially enhances alkali release and char reactivity, but significantly reduces both during the final stage of the gasification. The observed effects on char gasification become more pronounced with increasing amount of bed material and increasing time the material experienced in an industrial process. The ash-layer on the used bed material is concluded to play an important role as a carrier of alkali and other active components. The char and bed material systems are closely connected under operational conditions, and their material exchange has important implications for the thermal conversion.
Place, publisher, year, edition, pages
Elsevier, 2022. Vol. 238, article id 107491
Keywords [en]
Char, Gasification, Fluidized bed, Alkali, Potassium, Ash
National Category
Energy Engineering Other Chemical Engineering
Research subject
Energy Engineering
Identifiers
URN: urn:nbn:se:ltu:diva-93045DOI: 10.1016/j.fuproc.2022.107491ISI: 000893047000008Scopus ID: 2-s2.0-85137630130OAI: oai:DiVA.org:ltu-93045DiVA, id: diva2:1696163
Funder
Swedish Energy Agency
Note
Validerad;2022;Nivå 2;2022-09-15 (joosat);
2022-09-152022-09-152023-09-05Bibliographically approved