EFFECT OF PREHEAT TREATMENT ON COAL-LIQUEFACTION

For the catalytic and noncatalytic liquefaction of Wandoan and Illinoi s No. 6 coals with anthracene oil and hydrogenated anthracene oil at 4 50 degrees C, the two-stage liquefaction with in situ preheat treatmen t at 250, 350, and 400 degrees C for 15 min gave higher yields of tolu ene solubles (TS) and hexane solubles (HS) than the one-stage liquefac tion without in situ preheat treatment. The effect of preheat treatmen t at low temperature on the yields of TS and HS is believed to result from the swelling of coal in the solvent. The two-stage Liquefaction i s also advantageous from the viewpoint of using a lower preheat temper ature than the liquefaction temperature, compared with the one-stage l iquefaction for the same reaction time.