eprintid: 10192717 rev_number: 7 eprint_status: archive userid: 699 dir: disk0/10/19/27/17 datestamp: 2024-05-24 08:14:14 lastmod: 2024-05-24 08:14:14 status_changed: 2024-05-24 08:14:14 type: article metadata_visibility: show sword_depositor: 699 creators_name: Hou, Fei creators_name: Zhong, Xiaoxing creators_name: Zanoni, Marco AB creators_name: Rashwan, Tarek L creators_name: Torero, José L title: Multi-step scheme and thermal effects of coal smouldering under various oxygen-limited conditions ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F44 keywords: Coal fires; Smouldering; Multi-step scheme; Thermal effects; Oxygen-limited note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: Coal smouldering fires are global disasters and notoriously challenging to characterize. To better understand combustion and chemistry within these coal fires, TG-DSC experiments were carried out in two different coal samples in nitrogen and oxygen-limited (including ambient air) atmospheres. A mechanism with 8-step reactions simulating coal combustion was proposed, including one drying, two pyrolysis, two oxygen adsorption, and three high-temperature oxidations. The kinetic parameters were optimized via a Genetic Algorithm (GA). It was found that this 8-step mechanism created unnecessary overfitting to the TGA data. Therefore, two alternative schemes were developed with 5- and 4-step, which included and neglected oxygen adsorption, respectively. To compare the two schemes, GA and Gaussian multi-modal fitting were used to quantify the mass change rates in each step and their thermal effects as functions of oxygen concentrations. Moreover, the heat flow rates of coal samples were calculated and compared with measured DSC curves. The results indicated that oxygen adsorption could play a critical role in the transition from water evaporation to high-temperature combustion, and the 5-step scheme could reflect coal's intrinsic oxygen-limited combustion characteristics more accurately. Altogether, this study provides novel insight into coal smouldering under oxygen-limited conditions. date: 2024-07-15 date_type: published publisher: Elsevier BV official_url: http://dx.doi.org/10.1016/j.energy.2024.131421 full_text_type: other language: eng verified: verified_manual elements_id: 2271688 doi: 10.1016/j.energy.2024.131421 lyricists_name: Rashwan, Tarek lyricists_name: Torero Cullen, Jose lyricists_id: TLRRA25 lyricists_id: JLTOR59 actors_name: Torero Cullen, Jose actors_id: JLTOR59 actors_role: owner full_text_status: restricted publication: Energy volume: 299 article_number: 131421 issn: 0360-5442 citation: Hou, Fei; Zhong, Xiaoxing; Zanoni, Marco AB; Rashwan, Tarek L; Torero, José L; (2024) Multi-step scheme and thermal effects of coal smouldering under various oxygen-limited conditions. Energy , 299 , Article 131421. 10.1016/j.energy.2024.131421 <https://doi.org/10.1016/j.energy.2024.131421>. document_url: https://discovery.ucl.ac.uk/id/eprint/10192717/1/Fei-Manuscript-upload.pdf