Porous activated carbon fibre (ACF) materials, as a recycled absorbent, have been widely applied in the harmless disposal of volatile organic chemicals (VOCs). In order to reduce the energy consumption of cyclic regeneration process and avoid second pollution of high concentration VOCs, there is an urgent need to develop a synergistic regeneration method to recover the adsorptive capacity of ACF and achieve the in‐situ degradation of VOCs simultaneously. Due to the outstanding oxidation performance of ozone, ozonization was used to degrade VOCs adsorbed by absorbent materials and has a potential advantage in combination with the traditional electrothermal desorption technology. In this work, a three‐dimensional pore‐scale lattice Boltzmann method (LBM) is established to solve the convective heat and mass transfer processes considering the desorption and ozonization effects. Using this numerical model, a pore‐scale simulation is performed to investigate the reactive and desorptive transport behaviours in the reconstructed pore structure of ACF felt, which is regenerated using the electrothermal desorption process combined with the ozonization degradation method. The simulation works reveal the effects of key operation parameters on the desorption and degradation mechanisms into the pores of ACF felt during this combined regeneration process. The numerical results show that the flow velocity of carrier gas plays an important role on the performance of the combined regeneration process. The approach of reducing the carrier gas velocity would obviously improve the degradation ratio of VOC and the efficiency of the combined regeneration process.