The use of thermogravimetry in establishing the Fischer tar of a series of South African coal types

A method has been developed, by which the tar producing propensity of coal (Fischer assay) can be assessed from a single trace of a thermogravimetric simulation of the proximate analysis of coal. It was found that, for a suite of 22 South African coal types under well defined experimental thermogravimetric conditions, the mass loss observed in the temperature interval of 460–510 °C is related to the Fischer assay by the formula: Y=1.17X−2.0 where Y represents the expected Fischer tar and X represents the observed mass loss in the 460 and 510 °C temperature interval as calculated on a dry, ash free basis. The co-efficient of correlation, r2, was found to be >0.91.