Spatiotemporal Evolution and Expansion Potential of the Reaction Zone in a Solar-Driven Biomass Pyrolysis Reactor Packed with SiC Foam

This study performed a CFD-based analysis to assess the reaction-region expansion potential of a solar-driven biomass pyrolysis reactor packed with SiC foam. Reacted volume fraction (RVF), temperature volume fraction (TVF), and the operational conversion front defined by the 700 K isotherm were used to quantify the formation and propagation of the effective reaction region. The results show that the operational conversion front in the SiC foam reactor continued to propagate toward the unreacted region without apparent stagnation. The available time window for further front propagation was approximately five times larger than the time required to cover the remaining unreacted region near the original bed. Moreover, under a conservative assumption for a 12.5% reactor extension, the required finite axial temperature gradient was about two orders of magnitude larger than the local axial temperature gradient at the original bed end. These results indicate that the expanded reaction region can compensate for the feedstock loading capacity loss caused by the SiC foam skeleton, while the reactor still retains further expansion potential.