Characterisation of inorganic constitutions of condensate and solid residue generated from small-scale ex situ experiments in the context of underground coal gasification

Sadasivam, Sivachidambaram ORCID: https://orcid.org/0000-0002-2305-0292, Zagorščak, Renato, Thomas, Hywel Rhys ORCID: https://orcid.org/0000-0002-3951-0409, Kapusta, Krzysztof and Stańczyk, Krzysztof 2022. Characterisation of inorganic constitutions of condensate and solid residue generated from small-scale ex situ experiments in the context of underground coal gasification. Environmental Science and Pollution Research 29 , pp. 2203-2213. 10.1007/s11356-021-15780-8

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Abstract

This paper deals with the characterisation of inorganic constitutions generated at various operating conditions in the context of underground coal gasification (UCG). The ex situ small-scale experiments were conducted with coal specimens of different rank, from the South Wales Coalfield, Wales, UK, and Upper Silesian Coal Basin, Poland. The experiments were conducted at various gaseous oxidant ratios (water: oxygen = 1:1 and 2:1), pressures (20 bar and 36 bar) and temperatures (650°C, 750°C and 850°C). Increasing the amount of water in the oxidants proportionately decreased the cationic elements but increased the concentrations of anionic species. The temperature played minor impact, while the high-pressure experiments at temperature optimum to produce methane-rich syngas (750°C) showed significant reduction in cationic element generation. However, both coal specimens produced high amount of anionic species (F, Cl, SO4 and NO3). The “Hard” bituminous coal from Poland produced less gasification residues and condensates than the South Wales anthracitic coal due to its higher reactivity. The inorganic composition found in the solid residue was used in the theoretical calculation to predict the dissolved product concentrations when the solid residue interacts with deep coal seam water in the event of UCG cavity flooding. It was evident from the solubility products of the Cr, Ni and Zn that changes in the groundwater geochemistry occur; hence, their transportation in the subsurface must be studied further.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering
Additional Information:	This article is licensed under a Creative Commons Attribution 4.0 International License
Publisher:	Springer
ISSN:	0944-1344
Date of First Compliant Deposit:	8 August 2021
Date of Acceptance:	29 July 2021
Last Modified:	24 Aug 2023 20:43
URI:	https://orca.cardiff.ac.uk/id/eprint/143235

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