Research on the methanation properties of biomass gasification simulation based on alkali-modified Ni/Al₂O₃ catalysts

In this paper, the Ni/Al2O3 monolithic catalyst with 15% Ni content was prepared using cordierite as a matrix, and the catalyst was modified with 10% NaOH to study the methanation performance of biomass gasification simulated gas based on alkali-modified Ni/Al2O3 monolithic catalyst. BET, TEM, H2-TPR, XRD, CO2-TPD and TG were used to characterize the physicochemical properties of the catalyst before and after modification. The results indicated that the CO conversion rate trends of unmodified and modified Ni/Al2O3 monolithic catalysts over 2 h were fundamentally consistent. However, the Ni/Al2O3 catalysts modified for 2 h demonstrated significantly enhanced performance compared to those modified for 1 h. Regarding CH4 selectivity, the modified Ni/Al2O3 catalyst exhibited markedly better performance than the unmodified Ni/Al2O3 catalyst, confirming the enhanced methane performance of the alkali-modified Ni/Al2O3 monolithic catalyst. Under optimized conditions (H2/CO volume ratio of 3∶1, space velocity of 10000 mL/(g·h), and temperature of 400 °C), the methanation performance of the Ni/Al2O3 monolithic catalyst modified for 2 h reached its peak, achieving a CO conversion rate of 97% with 100% CH4 selectivity.