Low-Temperature Atmospheric Pyrolysis of Coal in Presence of SeO₂ and Liquefaction of Pyrolyzed Coal

Abstract

Gas evolution from coal heated at a fairly low temperature in the presence of SeO₂ and liquefaction behavior of the treated coal were examined for different coals. During atmospheric pyrolysis of coal with SeO₂, gas evolution was observed at extremely low temqeratures below 473 K. The gas was shown to consist of CO, CO₂ and H₂O. Combined with the gas evolution characteristics with gas composition from various aromatic model compounds, those gases were supposed to be originated mostly from carboxyl and methyl groups in coal and oxygen from SeO₂. The solid residue after the pyrolysis was liquefied using a sufficient amount of tetralin as a solvent under 10MPa of nitrogen at 723K. The results clearly showed that the SeO₂-treated coals give higher yields of pyridineand benzenesolubles than their parent coal due to improved coal reactivity and catalytic effects of SeO₂ and/or Se formed during pyrolysis.