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. Acombination 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°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.