Fixed-bed hydropyrolysis tests have been conducted on a UK bituminous
coal (Gedling), the Wyodak Argonne Premium coal sample and the high-su
lfur Mequinenza lignite at a pressure of 15 MPa with heating rates of
5 and 300 K min(-1). The tar yields and overall conversions increased
markedly by similar to 5-20 wt% daf coal as the heating rate was decre
ased from 300 to 5 K min(-1) for final temperatures of 520 and 600 deg
rees C, both with and without a sulfided molybdenum catalyst. Conversi
ons of >90 wt% were achieved with slow heating in catalytic hydropyrol
ysis for all three coals. The small increases in gas yield indicated t
hat tar-forming as opposed to hydrogasification reactions are promoted
by slow heating. These results demonstrate the value of slow heating
for analytical applications of hydropyrolysis, which include the deter
mination of organic sulfur forms and the covalently bound biomarker hy
drocarbons in coals and petroleum source rocks. Copyright (C) 1996 Els
evier Science Ltd.