Analysis of bed agglomeration during gasification of wheat straw in a bubbling fluidised bed gasifier using mullite as bed material

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Show simple item record Mac an Bhaird, Seán T. Walsh, Eilín Hemmingway, Phil McDonnell, Kevin et al. 2015-02-24T15:56:53Z 2015-02-24T15:56:53Z 2014 Elsevier en 2014-03
dc.identifier.citation Powder Technology en
dc.description.abstract The quantity and composition of the ash content of straw poses technical challenges to its thermal conversion and have been widely reported to cause severe ash sintering and bed agglomeration during fluidised bed gasification. Literature indicates that a combination of reactor design and bed material measures is required to avoid defluidisation at temperatures above 800 °C. Using scanning electron microscopy and energy dispersive X-ray spectroscopy this study investigated the initial agglomeration of a mullite bed during the gasification of wheat straw in a small scale, air blown bubbling fluidised bed. The results show that the temperatures along the height of the bed converge prior to any marked drop in pressure or heating of the lower freeboard. This convergence was seen to occur at temperatures close to 750 °C in repeated gasification experiments. Energy dispersive X-ray spectroscopy indicates coating-induced agglomeration caused by the reaction of alkali metals with silica. Scanning electron microscopy under high magnification revealed a layered structure to the agglomerates, where ash particles are subsumed into a fused material. This suggests the formation of agglomerates by the three step agglomeration process postulated by other authors. Analysis of indices used to predict agglomeration on the basis of a fuel's ash content and composition indicates that the Alkali Index is the most accurate, successfully predicting agglomeration for 7 of the 9 fuels where agglomeration was observed. en
dc.description.sponsorship Science Foundation Ireland en
dc.language.iso en en
dc.publisher Elsevier en
dc.rights This is the author’s version of a work that was accepted for publication in Powder Technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Powder Technology (VOL 254, ISSUE 2014, (2014)) DOI: 10.1016/j.powtec.2014.01.049 en
dc.subject Bubbling fluidised bed en
dc.subject Gasification en
dc.subject Wheat straw en
dc.subject Mullite en
dc.subject Bed agglomeration en
dc.subject Predictive indices en
dc.title Analysis of bed agglomeration during gasification of wheat straw in a bubbling fluidised bed gasifier using mullite as bed material en
dc.type Journal Article en
dc.internal.availability Full text available en
dc.status Peer reviewed en
dc.identifier.volume 254 en
dc.identifier.startpage 448 en
dc.identifier.endpage 459 en
dc.identifier.doi 10.1016/j.powtec.2014.01.049
dc.neeo.contributor Mac an Bhaird|Seán T.|aut|
dc.neeo.contributor Walsh|Eilín|aut|
dc.neeo.contributor Hemmingway|Phil|aut|
dc.neeo.contributor McDonnell|Kevin|aut|
dc.neeo.contributor et al.||aut|
dc.description.othersponsorship Department of Communications, Energy and Natural Resources en
dc.internal.rmsid 465282722 2015-02-17T12:35:50Z

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