Assessment of nature and distribution of inertinite in Indian coals for burning characteristics

Maceral composition and mean reflectance (Rr) of coal are considered to be important parameters, which influence the coal combustion characteristics. Vitrinite and liptinite are traditionally considered to be reactive components towards combustion. Numerous studies on Gondwana coals suggest that some inertinites, low in reflectance having mean reflectance up to 1.30%, show good burning behaviour and they can even be more reactive than vitrinite. Thermogravimetric analysis (TGA) technique has been used to assess combustion characteristics of the coal samples. The traditional parameters such as fuel ratio and rank, as reflected by vitrinite reflectance, did not correlate well with the TGA parameters. Rather, TGA parameters were found to show good correlation with the petrofactor, which combines the effect of the rank and the total reactive macerals content, which includes the reactive macerals (vitrinite, semivitrinite, liptinite) and low reflecting reactive inertinites. The study indicates the necessity of considering the role of low rank inertinites while assessing the combustion behaviour of inertinite rich non-coking/non-caking coals.