Utilization of carbonaceous materials to restore the coking properties of weathered coals

Castro Diaz, Miguel; Fernanda Vega, Mar�a; Barriocanal, Carmen; Snape, Colin

Abstract

Coking coals with different rank and maceral compositions have been weathered, and their fluidity has been determined through high-temperature rheometry. The pristine and weathered coals were blended with carbonaceous additives comprised of coal tar, diesel fuel, high-density polyethylene, sugar beet roots, lignin, and bio-oil in order to produce blends with optimum fluid characteristics. The addition of only 3 wt % coal tar to a high-rank coal weathered for 6 months completely restored its fluid properties, and the addition of 3 wt % diesel fuel was able to restore the fluidity of the coal but only after shorter weathering periods (4 months). However, the strength parameter R1 (particles > 0.6 mm) of the semicokes obtained from these blends at 700 °C was lower than that of the pristine coal by 3%. Biomass additives such as sugar beet roots and lignin were found to reduce the fluidity of a weathered coal with medium-volatile-matter content (25 wt % dry ash free (daf)) to levels similar to those encountered in good coking coals. Although sugar beet roots reduced the strength of the semicoke obtained from the blend, the blend with lignin produced a semicoke with strength similar to that of the pristine coal. The lower volatility matter content in lignin compared to sugar beet roots and its high oxygen content (∼25 wt %) could limit fissure formation in the semicoke and facilitate the cohesion with the oxidized coal matrix, respectively.

Citation

Castro Diaz, M., Fernanda Vega, M., Barriocanal, C., & Snape, C. (2015). Utilization of carbonaceous materials to restore the coking properties of weathered coals. Energy and Fuels, 29(9), 5744–5749. https://doi.org/10.1021/acs.energyfuels.5b01575

• Journal Article Type: Article
• Acceptance Date: Jan 1, 2015
• Publication Date: Aug 30, 2015
• Deposit Date: Sep 13, 2018
• Journal: Energy and Fuels
• Print ISSN: 0887-0624
• Electronic ISSN: 1520-5029
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 29
• Issue: 9
• Pages: 5744–5749
• DOI: https://doi.org/10.1021/acs.energyfuels.5b01575
• Public URL: http://www.scopus.com/inward/record.url?eid=2-s2.0-84941925677&partnerID=40&md5=91fcd46db776aa612cf3fc392b9abef4
• Publisher URL: https://pubs.acs.org/doi/10.1021/acs.energyfuels.5b01575
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