Composition of Coals from Republic of Tuva and Their Extracts Based on Pyrolysis and TGA Data

Ashless extracts, hypercoals, were obtained from Tuvan coals of the Ulug-Khem basin by dissolving them in N -methylpyrrolidone. The yield of the extracts was 27.3–79.4%, and their ash content was 0.5–0.8%. The composition of the products of pyrolysis, carried out at 420°C, of the initial coals and the hypercoals obtained from them was studied. It was found that high volatile bituminous coal (coal from the Elegest deposit) can be extracted most effectively. The qualitative and quantitative compositions of pyrolysis products were not fundamentally different in the initial coals and the corresponding extracts. According to TGA data, the decomposition of extracts (hypercoals) occurred at lower temperatures relative to that of the original coals with a high yield of volatile components.