Studies of ignition behaviour of biomass particles in a down-fire reactor for improving co-firing performance

Li, J., Paul, M. C. and Czajka, K. M. (2016) Studies of ignition behaviour of biomass particles in a down-fire reactor for improving co-firing performance. Energy and Fuels, 30(7), pp. 5870-5877. (doi:10.1021/acs.energyfuels.6b01065)

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Abstract

To realize large percentage biomass co-firing with coal in existing coal-fired boilers, the combustion behaviour of biomass is expected to be similar or comparable to that of coal. When co-firing with coal, biomass is not necessarily to be ground as fine as the dedicated coal particles due to its higher reactivity. With aim of achieving promising performance of co-firing with dedicated coal particles, the determination of suitable particle size of biomass becomes important. The paper investigates experimentally the ignition behaviour of three biomass materials in a down-fire reactor associated with thermogravimetric analyser (TGA). TGA results showed that the devolatilization process is accelerated by the presence of oxygen, but failed to identify the impacts of particle size on the ignition behaviour of biomass. However, the ignition testing results based in the down-fire reactor clearly showed that ignition delay time of a large biomass particle is longer than that of smaller one. In addition, being injected into the furnace, the softwood particles take a longer residence time to be ignited than the straw particles at same sizes, which agrees well with their reactivity analysis in TGA. Moreover, the ignition test results suggested that the ignition mechanism of biomass could be alternated from homogeneous to the heterogeneous ignition when the furnace temperature is increasing; at high enough furnace temperatures, the ignition predictably occurs at the particle surface without requiring the start of devolatilization. The results quantitatively demonstrate the effects of particle size on the ignition delay time of biomass, which, together with the transport phenomena and surrounding atmosphere, can contribute to control the biomass combustion profile and co-firing performance.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Paul, Dr Manosh and Li, Dr Jun
Authors: Li, J., Paul, M. C., and Czajka, K. M.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Energy and Fuels
Publisher:American Chemical Society
ISSN:0887-0624
ISSN (Online):1520-5029
Published Online:15 June 2016
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in Energy and Fuels 30(7): 5870-5877
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
618711Impact Acceleration Account (IAA - EPSRC)Jonathan CooperEngineering & Physical Sciences Research Council (EPSRC)EP/K503903/1VICE PRINCIPAL RESEARCH & ENTERPRISE