CO rich syngas production from catalytic CO2 gasification-reforming of biomass components on Ni/CeO2

Abstract

The advancement of biomass utilization technology is vital for addressing global climate change and the depletion of fossil resources. CO rich syngas production from the CO2 gasification-reforming of biomass components (cellulose, xylan, lignin, and starch) was investigated by a two-stage fixed bed reactor. The four biomass components were heated from room temperature to 600 °C in a CO2 atmosphere, among which lignin exhibited the highest residue fraction (51.6 wt.%) and the lowest gas yield (5.7 mmol gbiomass−1), whereas cellulose demonstrated the highest gas yield from CO2 gasification-reforming (14.6 mmol gbiomass−1). Nanorod CeO2 supported Ni catalysts were used to enhance volatile (tar) CO2 reforming reactions, and the gas yield increased by 104.3 % for cellulose, 103.3 % for xylan, 149.3 % for lignin, and 128.3 % for starch compared with noncatalytic CO2 gasification-reforming. Furthermore, the structure of fresh and used catalysts were characterized by X-ray diffraction (XRD), N2 adsorption/desorption isotherm, scanning electron microscope (SEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), H2-temperature programmed reduction (H2-TPR), and thermogravimetry (TGA). For the CO2 gasification-reforming of cellulose, the optimum CO yield of 27.6 mmol gbiomass−1 was achieved at a gasification/reforming temperature of 600/700 °C and a biomass/catalyst ratio of 6.25 using 2 %Ni/CeO2 catalyst. The stability tests of catalysts showed an approximately linear decrease in CO yield with the increase of the number of cycles, and catalyst deactivation resulted from Ni sintering and coke deposition.