Characteristics and kinetics of catalytic degradation of immature kerogen in the presence of mineral and salt

In the present work, a series of simulation experiments were carried out on isolated kerogen and mixtures of kerogen–montmorillonite and kerogen–potassium carbonate to investigate the effects of mineral and salt on the generation of various pyrolysates. A kinetic model of pyrolysate generation was developed which takes into account the effects of the added mineral and salt on kinetic parameters. It is found that montmorillonite and potassium carbonate (K2CO3) act as a catalyst to promote the degradation of kerogen, to increase the yield of gas and light hydrocarbons and to decrease the activation energies for the generation of gas and light hydrocarbons. In the generation of heavy hydrocarbons, however, K2CO3 exhibited feeble catalytic action. In contrast, montmorillonite decreased the yield of heavy hydrocarbons due to the retention on mineral surfaces. The catalytic effects of montmorillonite and K2CO3 become small and weak with increasing temperature. The catalytic action of montmorillonite and K2CO3 on the kerogen degradation can be tentatively accounted for by carbonium ion mechanism and electron transfer mechanism, respectively.