High-purity syngas production by cascaded catalytic reforming of biomass pyrolysis vapors

A novel pyrolysis followed by in-line cascaded catalytic reforming process without additional steam was developed to produce high-purity syngas from woody biomass. The key to the proposed process is the construction of a cascaded biochar + NiAl2O4 catalytic reforming process in which biochar acts as a pre-reforming catalyst, and NiAl2O4 acts as a primary reforming catalyst. The large oxygenates in the pyro-vapors are deeply cracked in the biochar layer due to the increased residence time in the hot-biochar bed. The remaining small molecules are then reformed with the autogenerated steam from pyrolysis catalyzed by the reduced Ni-0 species in the NiAl2O4 catalyst (NiAlO). The results showed that the yield of syngas for the optimized process was 71.28 wt % (including 44.44 mg-H-2/g-biomass and 536.48 mg-CO/g-biomass), and the CO2 yield of the process was only 3 kg-CO2/kg-hydrogen. High-purity syngas with 89.47 vol% of (H-2 + CO) was obtained, and the gas energy conversion efficiency (GECE) of the process reached 75.65%. The study shows that in the cascaded catalytic reforming process, cracking of the large oxygenates and reforming of the small molecules are promoted sequentially in separated biochar + NiAlO catalyst layers, which maximizes the syngas production and improves the activity and stability of the Ni-based catalyst.

Automated summary

A novel pyrolysis followed by in-line cascaded catalytic reforming process without additional steam was developed to produce high-purity syngas from woody biomass. The key to the proposed process is the construction of a cascaded biochar + NiAl2O4 catalytic reforming process in which biochar acts as a pre-reforming catalyst, and NiAl2O4 acts as a primary reforming catalyst. The study showed that in the cascaded catalytic reforming process, cracking of the large oxygenates and reforming of the small molecules are promoted sequentially in separated biochar + NiAlO catalyst layers, which maximizes the syngas production and improves the activity and stability of the Ni-based catalyst.