Helena Jönsson, Lars-Ove Jönsson
Thermal degradation by pyrolysis is highly temperature dependent, and the distribution of pyrolysis products is strongly dependent on the actual temperature at thermal decomposition. This leads to problems with reproducibility since the pyrogram is highly influenced by not only the steady-state temperature of the pyrolyzer, but also how the final temperature is reached. Therefore the time to reach the temperature in isothermal pyrolysis, the temperature rise time, is a vital characteristic of the pyrolysis process. Indeed, if the half decomposition time is of the same order of magnitude as the temperature rise time, most of the sample will be pyrolyzed below the steady state temperature. The temperature rise time shall be as short as possible to ensure reproducibility and well-defined pyrolysis conditions. In the present work a filament pyrolyzer is used to investigate the influence of the temperature rise time on the resulting pyrograms, with temperature rise times ranging from milliseconds to minutes. The sample is placed directly on the heated filament, and the pyrolysis temperature is measured by two independent methods: by resistance and by light emission.
theory, Arrhenius plot, temperature rise time, TRT, temperature time profile, TTP, fractionated pyrolysis