Proximate analysis, rheological properties and technological applications of some Nigerian coals

Background: Nigeria is endowed with large coal deposits, but some of them are yet to be explored. A combination of proximate analysis and rheological properties were used in characterizing the newly discovered Tai, Garin Maiganga and Shankodi-Jangwa coals in order to determine their suitable applications. Results: Tai, Garin Maiganga and Shankodi-Jangwa coals were found to have moisture contents of 9.61%, 5.51% and 1.33%; volatile matter contents of 45.11%, 40.53% and 17.37%; ash contents of 23.40%, 20.42% and 17.37%; and fixed carbon contents of 24.11%, 34.75% and 57.57%, respectively. Shankodi-Jangwa coal had the highest percentage of sulphur (1.63%), while both Tai and Garin Maiganga coals had sulphur contents of less than 1%. The agglomerating and rheological properties of the coals revealed that only Shankodi-Jangwa coal has some coking properties with a crucible number of 3.0, temperature range of 107(o)C, maximum fluidity of 300 and dilatometric G value of 0.96, indicating that it is a low-plasticity and medium-coking coal, which may be blended with strongly coking, low-ash, low-sulphur and high-fluidity coal. Conclusions: The results indicate that all the coal samples could be suitable for liquefaction; Shankodi-Jangwa coal may be suitable for hydro-gasification in the production of methane. Classification of the Tai, Garin Maiganga and Shankodi-Jangwa coals using the International Standard Organization (ISO) chart revealed that the ISO code numbers are 900, 800 and 622, respectively.