Coking properties of perhydrous low-rank vitrains. Influence of pyrolysis conditions.
type: Dataset
description: Compositional transformations occurring during natural coalification generally lead to increased coking potential of coals characterised in the resulting cokes by large sizes of molecular orientation domains (MOD) determined through transmission electron microscopy with 002 dark field mode. In this study, two sets of perhydrous low-rank vitrains (WJV and UCV) have been pyrolysed using an open-system with two heating rates in an attempt to increase their coking potential. Results show that, despite the high potentialities of such vitrains for producing hydrocarbons, i.e. a suspensive medium efficient for their cokefaction, each of the pyrolysis methods does not lead to solid residues chemically equivalent to natural coking coals, since the cokes from these residues are always made of smaller MOD than those obtained for coking coals. For comparison, a similar characterisation, carried out on a conventional vitrain (Fouthiaux) pyrolysed in a confined-system which prevents the release of hydrocarbons, leads also to non-coking coals. The formation of such MOD is likely due to the peculiar chemical composition of the precursors and/or the pyrolysis conditions. FTIR data show that perhydrous vitrains are characterised by a low degree of condensation of aromatic units with a very small concentration of aromatic rings of large size. Thermal treatment originates depolymerisation reactions in the vitrinite network with the formation of low molecular weight products which are not efficient to form large anisotropic domains. The oxygen, present in relatively high amount in some vitrains (UCV and Fouthiaux) might also act as a crosslinking agent preventing the formation of large MOD. Furthermore, while open-medium pyrolysis leads to an important effluent release, as shown by the rapid decrease of H/C ratio, hydrocarbon effluents are conversely retained within the coal matrix in the case of confined-medium pyrolysis. However, the latter pyrolysis induces secondary cracking reactio…
issued: 2026-05-20T03:18:23.015592
language: en
modified: 2026-05-20T03:18:23.015606
contact point: Organization
  fn: CCSD
keyword: chemical-structure
keyword: coking-properties
keyword: infoeu-reposemanticsarticle
keyword: journal-articles
keyword: pyrolysis
keyword: sdustugcsciences-of-the-universe-physicsearth-sciencesgeochemistry
keyword: tem-002-dark-field-mode
keyword: vitrain
landing page: 0165-2370

Coking properties of perhydrous low-rank vitrains. Influence of pyrolysis conditions.
type: Distribution
format: HTML
issued: 2026-05-20T03:18:23.035003
modified: 2026-05-20T03:18:22.973500
access URL: https://insu.hal.science/hal-00069369

test_moissonnage_selune
type: Agent