Kinetics of the pan fibre stabilization process

摘要

The polyacrylonitrile fibre stabilization process was examined as a heterogeneous gas-solid reaction using the well-known model with changing voidage to represent the fibres as a system of a large number of identical microfibriles. The model includes determination of the effective diffusivity of oxygen within oxidized PAN fibres based on the corresponding correction for temperature and actual conversion degree, as well as determination of the reaction rate between the oxygen and active groups on the shrinking core of microfibriles. Using experimental data of the overall conversion degree of PAN fibres oxidized at isothermal conditions (220℃) the reaction rate constant was determined. The results obtained show that the model used has the ability to predict the overall conversion degree under a variety of conditions, with a consistent set of material constants.