Catalytic Pyrolysis of Rice Hull with Char Composite from Lignin and Spent Lithium-Ion Battery Cathode

Abstract

The char modified by the battery cathode material was studied for catalytic pyrolysis of rice hull (RH). Compared to the direct mixing, the addition of cathode material to char by the impregnation was more favorable to synthesize the lignin char catalyst (i.e. char 1) with hierarchical pore structure and larger specific surface area. The char 1 decreased the E_a of the RH pyrolysis from 79 kJ/mol to 66 kJ/mol. The char 1 decreased the yield of liquid product from 23.2% to 12.3% and increased the yield of gas product from 35.2% to 52.2%. The char 1 decreased the contents of acids from 20.6% to 3.6% and phenols (tar surrogates) from 29.4% to 8.0%. The increase of hydrocarbons and CO₂ indicated that the char catalysts had high catalytic reactivity in converting the oxygenated components (e.g., sugars, furans, acids, phenols) into light hydrocarbons (e.g., alkanes, aromatics) and micro-molecular gases (e.g., CO₂, H₂).

Keywords: rice hull, pyrolysis, char catalysts, spent lithium-ion battery cathode, Tar