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Ilmenite as alternative bed material for the combustion of coal and biomass blends in a fluidised bed combustor to improve combustion performance and reduce agglomeration tendency

Garcia, Eduardo; Liu, Hao

Ilmenite as alternative bed material for the combustion of coal and biomass blends in a fluidised bed combustor to improve combustion performance and reduce agglomeration tendency Thumbnail


Authors

Eduardo Garcia

HAO LIU LIU.HAO@NOTTINGHAM.AC.UK
Professor of Energy Engineering



Abstract

Co-firing coal and biomass has the potential to reduce GHG emissions. However, high levels of alkali and alkaline metals in biomass ash can bring additional issues to the operation of coal-fired boilers. This study investigates the effects of ilmenite as the bed material on CO and NOx emissions and combustion efficiency of a coal and biomass blend, and the agglomeration tendency of the bed material with a pilot-scale (30 kWth) bubbling fluidised bed combustor. The experiments were carried out at 900 °C using a bituminous coal blended with wheat straw pellets at 40 wt% as the fuel and silica sand as the baseline bed material. Samples of agglomerates collected from the combustor and cyclone ash were characterised by SEM-EDS, XRD, and XRF. The results revealed that ilmenite could reduce the level of excess air required to achieve complete combustion due to lower CO emissions and less efficiency loss compared to silica sand. However, ilmenite increased NOx emissions. Furthermore, the characterisation of the obtained agglomerates and cyclone ash showed that ilmenite could hinder the K-rich molten substance attachment to the bed material, leading to significantly smaller agglomerates and hence less tendency towards defluidisation in comparison to silica sand.

Journal Article Type Article
Acceptance Date Aug 25, 2021
Online Publication Date Sep 3, 2021
Publication Date Jan 15, 2022
Deposit Date Sep 23, 2021
Publicly Available Date Sep 4, 2022
Journal Energy
Print ISSN 0360-5442
Publisher Elsevier BV
Peer Reviewed Peer Reviewed
Volume 239
Article Number 121913
DOI https://doi.org/10.1016/j.energy.2021.121913
Keywords General Energy; Pollution; Mechanical Engineering; Building and Construction; Electrical and Electronic Engineering; Industrial and Manufacturing Engineering; Civil and Structural Engineering
Public URL https://nottingham-repository.worktribe.com/output/6297013
Publisher URL https://www.sciencedirect.com/science/article/pii/S0360544221021617?via%3Dihub
Additional Information This article is maintained by: Elsevier; Article Title: Ilmenite as alternative bed material for the combustion of coal and biomass blends in a fluidised bed combustor to improve combustion performance and reduce agglomeration tendency; Journal Title: Energy; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.energy.2021.121913; Content Type: article; Copyright: © 2021 Elsevier Ltd. All rights reserved.