PAHs emission from the pyrolysis of Western Chinese coal

Several organic and inorganic pollutants are released during coal utilization such as polycyclic aromatic hydrocarbons (PAHs). PAHs, due to their carcinogenic properties pose potential health hazards. The current work focused on the behavior of the 16 PAHs during pyrolysis process, an important step of all coal thermal conversion including combustion, gasification, and carbonization. The experiments were performed using a CDS-5250 pyroprobe which could be heated fast. The pyroprobe was coupled with GC–MS (Thermo DSQII/FOCUS GC) and the pyrolysis products were analyzed in situ. The emissions of the 16 USEPA priority-controlled polycyclic aromatic hydrocarbons from Western Chinese coal were measured under different pyrolysis conditions. The results showed that the emission concentrations of PAHs reach a maximum at a pyrolysis temperature of 800 °C. Emission concentrations of PAHs decreased with increasing rates of pyrolysis heating. PAHs emissions increased gradually with coal rank under the same pyrolysis conditions. A correlation between the yield of PAHs, coal rank and maceral was also demonstrated. Also in this study, the variety trend of the each species of 16 PAHs with pyrolysis temperature was observed and the reasons were discussed.