Structural analysis of chars generated from South African inertinite coals in a pipe-reactor combustion unit

N. Malumbazo, N. J. Wagner, J. R. Bunt, D. Van Niekerk, H. Assumption

Research output: Contribution to journalArticlepeer-review

45 Citations (Scopus)


An inertinite-rich medium rank C bituminous South African coal was utilized to generate chars in a pipe-reactor combustion unit. This unit generates chars at atmospheric pressures and temperature was controlled with N2 to a maximum of 1250 °C. Chemical structural changes were investigated at different reaction zones identified in the pipe-reactor combustion unit. A combination of FTIR, XRD and Solid State NMR experiments were used to characterize the coal/char/ash fractions produced in the reactor. These techniques revealed that the coal structure becomes disordered in the drying zone as well as in the beginning of the pyrolysis zone in the reactor. As the temperature increases towards the base of the reactor the coal structure becomes more ordered and well aligned until char is formed and converted. Major structural changes were seen to occur in the drying to the pyrolysis zones. Structural changes within the molecular core were observed with FTIR and XRD results obtained from samples taken from the drying zone to the combustion zone. However, 13C CP/MAS and dipolar dephasing experiments were not able to corroborate these structural changes of the coal/char/ash fractions produced in the reactor occurring in the reduction and combustion zones.

Original languageEnglish
Pages (from-to)743-749
Number of pages7
JournalFuel Processing Technology
Issue number4
Publication statusPublished - Apr 2011
Externally publishedYes


  • Aromaticity
  • C Solid State NMR
  • Coal structure
  • Pyrolysis
  • Structural ordering

ASJC Scopus subject areas

  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology


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