Sulfur release and transformation behaviors of sulfur-containing model compounds during pyrolysis under oxidative atmosphere

In this study, the sulfur release and transformation behaviors of tetradecyl mercaptan, dibutyl sulfide, phenylsulfide, 2-methylthiophene, benzothiophene and dibenzothiophene during pyrolysis were investigated by thermo-gravimetric analyzer coupled with mass spectrometer (TG–MS). The order of sulfurs release is dibutyl sulfide > 2-methylthiophene > tetradecyl mercaptan > benzothiophene > phenylsulfide > dibenzothiophene. The decomposition temperatures of all of the sulfur compounds are lower during pyrolysis under an oxidative atmosphere than that under inert and hydrogen atmospheres, which indicates that oxygen can break C–S bonds more easily than C–C bonds. The SO2 evolution of most sulfur model compounds except 2-methylthiophene and dibenzothiophene is derived mainly by decomposition of their transformation compounds rather than their native forms. Most sulfur compounds can be removed under an oxidative atmosphere with little loss of carbon.