Catalytic Hydrotreating for Nitrogen Removal from Coal Tar Pitch in Supercritical Fluid

Specific features of solid catalyzed reaction in supercritical fluid were discussed through the comparison of denitrogenation of coal tar pitch by using NiMo-Al₂O₃ catalyst in supercritical fluid (toluene/tetralin mixture) and in liquid (1-methyl naphthalene/tetralin mixture). Basic nitrogen compounds reacted faster than neutral nitrogen compounds on the solid-acid-catalyst in both cases. At 703 K and 15 MPa, and in the range of particle sizes from 0.11 to 0.85 mm where denitrogenation proceeded under chemical reaction control, the reaction rate in supercritical fluid was higher than that in the liquid.