CATALYTIC AND THERMAL-CRACKING OF COAL-DERIVED LIQUID IN A FIXED-BED REACTOR

A coal-derived liquid, obtained from the Coal Technology Corp.'s mild gasification process, was cracked over char produced from Pittsburgh N o. 8 coal mixed with Plum Run dolomite in the Foster Wheeler carbonize r. For the purpose of comparison, calcined Plum Run dolomite (PRD) cha r produced from Pittsburgh No. 8 coal, and silicon carbide (an inert m aterial) were also studied. Coal liquid feed was analyzed by sulfur-se lective gas chromatography (GC), liquid chromatography (LC), and proto n nuclear magnetic resonance (NMR) and for elemental composition. The gaseous products of cracking were analyzed for hydrocarbons using GC. Most sulfur in the feed was present in molecules heavier than dibenzot hiophene and was distributed in a variety of structures. The surviving coal liquid was analyzed by LC. The results indicated that deoxygenat ion of phenols, dealkylation of aromatic compounds (AR), and condensat ion of aromatic structures are some of the reactions occurring on the surface of bed materials. Energies of activation for homogeneous and f or heterogeneous pyrolysis of the coal liquid were calculated after se parating the rate of thermal cracking from the sum of rates of thermal and catalytic cracking.