Catalytic Pyrolysis of Herb Residues for the Preparation of Hydrogen-Rich Gas

Thermochemical conversion technology for the resource utilization of biomass can not only treat wastes polluting the environment but also efficiently generate hydrogen-rich gas for industrial applications. In this paper, the simulation calculation and experimental studies were employed to investigate the catalytic pyrolysis of herb residues for the preparation of hydrogen-rich gas. The results of thermogravimetry–Fourier transform infrared, kinetic, and thermodynamic studies showed that the catalytic pyrolysis of herb residues by 10 wt % Ni/CaO catalyst exhibited the lowest apparent activation energy compared to pyrolysis catalyzed with CaO or no catalyst. Under the catalysis of 10 wt % Ni/CaO and the temperature range of 500–700 °C, the content of H2 in the catalytic pyrolysis gas products of herb residues was higher, while the content of CO2 was lower. Furthermore, in the presence of 10 wt % Ni/CaO catalyst, the catalytic pyrolysis experiment of herb residues in a moving bed reactor was carried out at 500–700 °C. The results showed that the distribution of hydrogen-rich gas composition with an increasing temperature was consistent with the thermodynamic simulation results. Specifically, with a rising pyrolysis temperature, the H2 content increased initially and then decreased, which reached the highest ratio at 650 °C with an experimental value of 67.31 vol %.