Development of a petrographic technique to assess the spontaneous combustion susceptibility of Indian coals

Mohalik, N.K.; Lester, E.; Lowndes, Ian

Abstract

Petrographic studies are commonly used categorise the potential utilisation of coals. Eleven coal samples from the jharia coalfield (JCF), india, were studied using petrographic techniques to investigate maceral content, reflectance, and textural characteristics. Multiple test samples of each coal were slowly oxidised under controlled laboratory conditions from an ambient temperature of 30°c to 300°c to investigate the morphology of oxidised coals. The petrographic characterisation of the coals before and after oxidation showed important changes in both morphology and vitrinite reflectance. The oxidation of the coal particles produced three predominant textural changes: particles with homogeneous change of reflectance (HCv), particles with oxidation rims (ORv), and particles with no changes were observed (Uv) respectively. These textural characteristics were used to indicate how particles had interacted with oxygen at low temperatures during the early stages of oxidation. The morphological classification developed provides an alternative method to confirm the susceptibility of a coal to spontaneous combustion. Conventional thermal parameters such as crossing point temperature (CPT) were unable to identify the coals prone to spontaneous combustion. However, certain petrographic parameters could be combined with CPT values to provide a much more accurate measure for susceptibility to spontaneous combustion.

Citation

Mohalik, N., Lester, E., & Lowndes, I. (in press). Development of a petrographic technique to assess the spontaneous combustion susceptibility of Indian coals. International Journal of Coal Preparation and Utilization, https://doi.org/10.1080/19392699.2017.1360874

• Journal Article Type: Article
• Acceptance Date: Jul 25, 2017
• Online Publication Date: Nov 1, 2017
• Deposit Date: Oct 4, 2017
• Publicly Available Date: Nov 2, 2018
• Journal: International Journal of Coal Preparation and Utilization
• Print ISSN: 1939-2699
• Electronic ISSN: 1939-2702
• Publisher: Taylor and Francis
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1080/19392699.2017.1360874
• Keywords: Petrographic study, spontaneous combustion, morphology study of oxidised coal, principal component analysis and classification (PCCA), Fixed nonlinear regression models (FNRM)
• Public URL: https://nottingham-repository.worktribe.com/output/892229
• Publisher URL: http://www.tandfonline.com/doi/full/10.1080/19392699.2017.1360874
• Additional Information: This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Coal Preparation and Utilization on 1 November 2017, available online: http://www.tandfonline.com/10.1080/19392699.2017.1360874.
• Contract Date: Oct 4, 2017