Birley, RI, Jones, JM orcid.org/0000-0001-8687-9869, Darvell, LI orcid.org/0000-0002-4119-8485 et al. (5 more authors) (2019) Fuel flexible power stations: Utilisation of ash co-products as additives for NOx emissions control. Fuel, 251. pp. 800-807. ISSN 0016-2361
Abstract
This work investigated the effects of different ash co-products on the combustion of solid fuels, in particular the fuel-nitrogen behaviour: The fuel-ash additive combinations investigated were: Firstly, biomass ashes added to bituminous coals, representative of those used in power stations; Secondly, a low reactivity coal; Thirdly, a high-N biomass (olive cake) was chosen as a high reactivity fuel and studied with a power-station pulverised coal fly ash as an additive. These five solid fuels have a wide fuel ratio FR (i.e. the ratio of fixed carbon to volatile matter content). The ash additives were a pulverised fly ash (PFA) and a furnace bottom ash (FBA) from wood pellet combustion in a UK power station. Fuels (with and without additives) were studied for nitrogen partitioning during (i) devolatilisation and for (ii) NOX formation during combustion, using two different electrically heated drop tube furnaces (DTF) operating at 1373 K. Devolatilisation was also studied via ballistic-heated thermogravimetric analysis (TGA). The extent of impact of additives on volatile yield under devolatilisation conditions was dependent on fuel ratio, high FR has the greatest increase in volatile release when co-feeding the additive. Under devolatilisation conditions, there is a correlation between volatile nitrogen and carbon conversion for all the fuels tested. Thus, additives liberate more volatile-nitrogen from the coals and also deliver enhanced carbon conversion. A mechanism is proposed whereby ultra-fine particles and vapours of reactive compounds from the additives interact with the reacting fuel/char particle and influence N-release during both devolatilisation and char burn-out. The enhanced conversion of fuel-nitrogen to volatile-nitrogen and the reduction of char-nitrogen can lead to reductions of NOX emissions in emissions-controlled furnaces. This approach could assist fuel-flexible power stations in achieving their NOX emission targets.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 The Authors. Published by Elsevier Ltd. Published by Elsevier Ltd. This is an open access article under the CC-BY license (http://creativecommons.org/licenses/BY/4.0/). |
Keywords: | NOX; Coal combustion; Co-combustion; Nitrogen partitioning; Carbon conversion |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 18 Apr 2019 09:07 |
Last Modified: | 25 Jun 2023 21:47 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.fuel.2019.04.002 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:145021 |