Effectiveness of bed additives in abating agglomeration during biomass air/oxy combustion in a fluidised bed combustor

Chi, Hetian; Pans, Miguel A.; Sun, Chenggong; Liu, Hao

Abstract

In this study, molochite (calcined kaolin) and dolomite with particle sizes (ca.1 mm) similar to those of the sand bed materials of industrial-scale fluidised beds, rather than powders which were normally used by previous studies, were investigated as the bed additives to counter agglomeration with the combustion of wheat straw and miscanthus pellets in a 20 kWth bubbling fluidised bed combustor under both conventional air combustion and oxy-fuel combustion conditions. The performance of the additives in abating agglomeration was compared to that achieved with another agglomeration countermeasure, lime addition to fuel. Dolomite was found to be superior to molochite in terms of prolonging defluidisation time when firing wheat straw. When firing miscanthus, similar effects of these two bed additives on defluidisation time were observed. The most significant improvement to the combustion performance was achieved by lime addition to fuel for both fuels. Moreover, the oxy-fuel combustion atmosphere showed a great impact on the effectiveness of dolomite but little influence on the effectiveness of molochite. The agglomeration samples were analysed by CAMSIZER, XRD and SEM/EDX and the results were used to derive the possible anti-agglomeration mechanisms of the additives under both air and oxy combustion conditions.

Citation

Chi, H., Pans, M. A., Sun, C., & Liu, H. (2022). Effectiveness of bed additives in abating agglomeration during biomass air/oxy combustion in a fluidised bed combustor. Renewable Energy, 185, 945-958. https://doi.org/10.1016/j.renene.2021.12.072

• Journal Article Type: Article
• Acceptance Date: Dec 15, 2021
• Online Publication Date: Dec 22, 2021
• Publication Date: 2022-02
• Deposit Date: Jan 5, 2022
• Publicly Available Date: Jan 5, 2022
• Journal: Renewable Energy
• Print ISSN: 0960-1481
• Electronic ISSN: 1879-0682
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 185
• Pages: 945-958
• DOI: https://doi.org/10.1016/j.renene.2021.12.072
• Keywords: Renewable Energy, Sustainability and the Environment
• Public URL: https://nottingham-repository.worktribe.com/output/7165873
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0960148121017924