A TEST OF THE PARALLEL REACTION MODEL USING KINETIC MEASUREMENTS ON HYDROUS PYROLYSIS RESIDUES

Open-system kinetics are measured on extracted residues from hydrous p yrolysis to test aspects of the parallel reaction model and the assump tion of a single frequency factor for all energies. The absolute rates of the residues form a series supporting the concept that hydrous pyr olysis removes primarily the more reactive components at lower tempera ture. The parallel reaction model works well for the marine kerogen, e xcept for the small amount of refractory material in the highest tempe rature residue that is not represented adequately in kinetics from the initial sample because of measurement limitations. The kinetic parame ters derived from the unreacted coal do not work as well and predict t oo much remaining reactive material. The discrepancy may be caused by a weakness in the parallel reaction model, or due to the fact that the open-system kinetics are not intended to predict the generation and s ubsequent removal of extractable organic matter. That the parallel rea ction model works less well for coal confirms earlier concerns about t he complexity of oxygen-related reactions. The constant frequency fact or approximation works fairly well for the kerogen but marginally well for the coal. The frequency factor shifts about ten-fold over the act ivation energy range in the kerogen and about 100-fold over the activa tion energy range in the coals.