Abstract:The pyrolysis characteristic of poly vinyl chloride (PVC) was investigated by thermogravimetric analysis (TG). The effect of sample amount, pyrolysis time and temperature on the yield of hydrogen chloride (HCl), tar, gas and char during the production of HCl by PVC pyrolysis was studied. The pyrolysis products were analyzed by ion chromatography (IC), gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and the mechanism of HCl production from PVC pyrolysis was revealed. An optimal result could be obtained when 1.2g PVC was pyrolyzed at 400℃ for 30min when the carrier gas flow was 100mL/min. PVC pyrolysis included two decomposition stages, at the temperature of 260~320℃ and 390~600℃, respectively. With temperature increasing, tar yield enhanced from 0.95% to 20.29%, HCl yield raised from 25.69% to 53.76%, while char yield decreased from 54.39% to 11.27% and gas yield varied from 9.09% to 18.97%. H2, C2H4 and C3H6 were detected in the gas product when the temperature was below 400℃, while CH4, C2H6 and C3H8 were also found when the temperature was higher than 400℃. The unstable components converted to stable types when the temperature increased. In the first thermal decomposing stage, chain reactions for the removal of HCl were the main reactions, while in the second stage, the main reactions were tar reforming, molecular rearrangement, benzene removal and isomerization.