Hydrogen-rich gas formation from catalytic pyrolysis of biomass tar by aluminum dross coupled HZSM-5 co-loaded Ni-Fe bimetallic catalysts: Influence of co-carrier characteristics

This paper studied the hydrogen-rich gas production from catalytic pyrolysis of biomass tar using catalysts derived from aluminum dross (AD) combined with HZSM-5 molecular sieve co-supported Ni-Fe in a two-stage fixed-bed reactor. It revealed that the carrier characteristics played an important role in determining the Ni and Fe species form, textural properties, and catalytic abilities of the resulting catalysts. The surface properties and pore structure of aluminum dross activated by 3 mol/L H2SO4 (ASA) are improved. Especially, the hydrogen-rich gas production with the highest toluene conversion (91.96 %), highest gaseous efficiency (70.78 wt%), gas (H2, CH4, CO) yield was 110.5 mL/g-toluene, H2 ratio was 39.55 vol%, and the lowest solid yield (0.09 %) and carbon deposition (7.14 mg/g-catalyst) by the assisted-CO2 at the reforming temperature of 800 degrees C with the catalyst amount of 16 %. CO2 conversion of 84.37 % by catalytic pyrolysis of toluene under the CO2-assisted ASA combined with HZSM-5 co-supported Ni-Fe (Ni-Fe/ASA@HZSM-5) catalyst condition. The synergy factor of ASA and HZSM-5 molecular sieve as co-carriers on H2 and CO yield is 1.30 and 1.70, playing a dual role in improving the yields of H2 and CO, and realizes the coordinated regulation of catalytic action and thermal conversion action. Therefore, the Ni-Fe/ASA@HZSM-5 catalyst has good catalytic activity and stability, which realizes the recovery and utilization of waste resources, reduces the preparation cost of catalysts and provides a new idea for the preparation of catalysts used to catalyze cracking/reforming of biomass tar to produce hydrogen-rich gas.