Aromatization of oils from coal-tyre cothermolysis II. PAH content study as a function of the process variables

In this work, the PAH content in the oils obtained from hydro-cothermolysis have been analysed. The influence of the process variables (H-2 pressure, 1 and 10 MPa, different feed materials: coal, tyre and a blend of coal-tyre (1:1 in organic matter) in two reactors, tubing bomb and autoclave reactor s (TBR, AR), on PAH formation has been studied. Gas chromatography/mass spectrometry (GC/MS) is used as the main analytical technique after fractionation into four chemical fractions using neutral a lumina column chromatography (CC). As the complementary technique, thin lay er chromatography with flame ionisation detector (TLC/FlD) was used to comp are the analytical tool on the total aromatic compounds, leading to the con clusion that the nature of synthetic oils is also dependent on the analytic al technique. In relation to the variables studied, the lower the pressure the higher the concentration of PAH detected. The hydrogen abundance reduces the PAH cont ent. The hydropyrolysis of tyre, coal, and a blend of coal-tyre at the same conditions show that coal produces higher concentrations of PAH at hydroge nating conditions. PAHs that contain three and four cycles are the main PAH s detected regardless of the feed. (C) 2000 Elsevier Science B.V. All right s reserved.