Kinetic Analysis on Pyrolysis of Corn Straw Fermentation Residue

Abstract

Lignocellulose fermentation residue (FR) is a lignin-rich biomass material, which can be widely obtained as a solid waste from a fuel ethanol producing process. In this paper, kinetic analysis on the pyrolysis of FR was conducted through Coats-Redfern method via the instrument of thermal gravimetric analyzer. It was found that the pyrolysis of FR showed three weight loss stages: the stage from 30^oC to 180^oC could be attributed to the dehydration and degas process; the stage from 180^oC to 700^oC was the main pyrolysis of organics; the stage from 700^oC to 900^oC was due to a decomposition of minerals. Nine kinetic equations were tried for most probable mechanic model searching, while none of the models can be used to describe the whole process in the temperature from 150^oC to 700^oC, indicating that the pyrolysis is not a single mechanic process. In the range of conversion rate from 10% to 50%, the reaction is most probably a diffusion controlled process, with an increasing activation energy varied from 37.8 kJ/mol to 41.3 kJ/mol with increasing heating rate. In the range from 50% to 75%, a less satisfactory R² value no higher than 90.1% was given by the model of D3, and therefore tests on more models are necessary still.