No abstract

A study of low-rank coal conversion into liquid products by direct catalytic hydrogenation was undertaken. A soft brown coal from the ‘Tamnava’ field of the Kolubara mines characterized by a huminite reflectance of 0.27 ± 0.03% R R , ash content of 10.4 wt% (db), carbon content of 64.0 wt% (daf), and volatiles ca. 50 wt% (db), was submitted to liquefaction in a batch reactor. The effect of reaction parameters on both the yield and nature of liquefaction products was studied for temperatures ranging from 365 to 440°C, and pressure from 13.5 to 16.5 MPa, with process duration from 1 to 8 hours. The total coal conversion was high at all applied reaction conditions (84–93%, daf coal basis), pointing to a high reactivity of this coal. The yield of particular liquid products varied markedly depending on temperature and residence time. The yield of light-oil ( n -heptane soluble products) increased and that of asphaltenes decreased by increasing the temperature and prolonging the residence time. Changes in petrographic composition of the coal were examined by microscopic analysis. At more severe reaction conditions the content of semicoke and coke increased. With the increase of temperature at mild conditions, the proportions of both the reacted coal and granular residue increased, while the cenospheres and mineral matter decreased. The nature of the changes observed in the organic and mineral components of the coal grains was used to correlate the degree of coal conversion with the experimental conditions.

No abstract

No abstract

No abstract