Kinetic Study of Decomposition of ASR Residues after Pyrolysis in Inert and Oxidative Atmosphere

摘要

The kinetic studies on solid residues after pyrolysis from ASR (Automobile Shredder Residue) originated from STENA Metall AB have been performed with the use of thermogravimetry analysis TGA. The char after microwave pyrolysis has been pyrolyzed and combusted in the presence of helium and air respectively. The TG experiments have been performed with heating rate of 10, 20, 40, 60 and 100deg/min. The influence of heating rate for decomposition rate and the char reactivity was also analyzed. Three different decomposition peaks have been identified for pyrolysis process in the range of temperatures 230-430, 400-500 and 680-850 ℃, respectively. The activation energy (E_(act)) and pre-exponential (frequency) factor (A) were calculated from the DTG curves using Coats and Redfern (C&R) method and Doyle's (D), based on the assumption of an independent, parallel first order Arrhenius-type global kinetic model. The kinetic data were also obtained for small lab scale gasification process of ASR pyrolysis residues. The mass loss and the heating of sample are recorded. It was proved, that the char's heating rate plays a significant role in the conversion rate as well in the char reactivity. The relatively high ignition temperature of 630℃ would require the steam temperature to be well above 800℃. Thus, reasonable would be to use high temperature steam gasification for treating ASR residues after microwave pyrolysis.