Hydroliquefaction of subbituminous coal Effectiveness of pretreatment by organic reduction with Na or k

Abstract

Hydroliquefaction of subbituminous Taiheiyo coal, without any pretreatment and after organic reduction, was carried out in the presence of tetralin using fine iron powder as catalyst. Two pretreatment procedures were used (A) reduction of coal with Na in liquid ammonia solution and (B) treatment with K in refluxing THF. Samples of treated coal with well-dispersed iron powder were prepared by co-reduction of coal coated with FeBr 2 using both procedures. Non-catalytic liquefaction of coal treated by A showed double the yield of hexane-solubles compared with that from liquefaction of the original coal while non-catalytic liquefaction of the coal treated by B roughly tripled the hexane-solubles yield and consumed the same amount of hydrogen. The presence of iron powder increased hexane-solubles by 5 wt% while increasing benzene-solubles by 13 wt% compared with non-catalytic liquefaction of treated coal by procedure B. The coals prepared by co-reduction (A and B) showed highest conversion (73 and 77%) along with highest yield of HS (38 and 43%). This significant effect on hydroliquefaction could be correlated with a slight increase of hydrogen atoms added to coal organic materials and the loosening of clusters of aromatic sheets.