A comparative study of one-step and stepwise pyrolysis of furfural residue and its kinetic analysis

Abstract

Furfural residue (FR), a solid waste from the furfural production industry, is rich in cellulose and lignin. It has great potential for producing bio-fuels and bio-chemicals through pyrolysis. To examine the effects of heating programs on the product distribution of FR pyrolysis, stepwise and one-step pyrolysis processes were compared using a commercial Py-GC/MS system. During the stepwise pyrolysis, the acids had a maximum yield at 300 °C, while the outputs of the ketones/aldehydes, furans, esters, alcohols, and sugars were the most abundant at 350 °C. The production of aromatics increased, whereas the nitrogen-containing compounds decreased as the temperature increased from 300 °C to 500 °C. The relative percentages of the aromatics and furans from the one-step pyrolysis were much higher than those from the stepwise pyrolysis. In contrast, the acids, sugars, alcohols, nitrogen-containing compounds, and alkanes/olefins from the stepwise pyrolysis were higher than those from the one-step pyrolysis at 500 °C. The kinetic analysis showed that the activation energy of the FR was reduced from between 212 and 214 kJ/mol to between 189 and 191 kJ/mol as the degree of conversion (α) increased from 20% to 60%, before increasing from 191 kJ/mol to 478 kJ/mol as α further increased from 70% to 90%.