Catalytic hydrogenation of Tamnava (Yugoslavia) soft brown coal

摘要

The effect of the reaction conditions in the catalytic hydrogenation of Tamnava (Yugoslavia) soft brown coal on the yield of the reaction products and the conversion degree was studied in this paper. Hydrogenation of the coal, dispersed in tetralin, in the presence of the Co-Mo-Al_2O_3 catalyst was carried out in a stream of hydrogen in a batch reactor. The yields of oil (liquid products soluble in n-heptane), asphaltenes and the solid residue served as a basis for the calculation of coal conversion. A high degree of coal conversion (>85%) was achieved in all applied reaction conditions but the yields of individual products varied. Generally, the yield of asphaltenes was lower and that of oil higher by increasing the reaction temperature and the residence time. The maximum oil yield was obtained at temperatures below the highest used (440 ℃) with a residence time shorter than eight hours. Changes in the pressure affected the product yields to a lesser extent. Micropetrographic analysis confirmed the surprisingly high reactivity of Tamnava soft brown coal in the catalytic hydrogenation process as well as the effect of the reaction conditions on the conversion of the coal into liquid products.