Infrared heated pyrolysis of corn stover: Determination of kinetic and thermodynamic parameters

Abstract

High-value bio-oil and gaseous products can be produced by pyrolysis of corn stover. This work presents a systematic study on pyrolysis characteristics of corn stover using an innovative infrared heated pyrolysis reactor. Firstly, the analytical pyrolysis was performed in a thermogravimetric (TG) analyzer at 10, 20, 30 and 40 °C/min to investigate the thermal degradation behaviors, and the pyrolysis kinetics and thermodynamics parameters were calculated. The activation energies calculated by FWO and KAS method were 19.61–38.33 kJ/mol and 11.40–29.51 kJ/mol respectively at conversion fractions (α) ranging from 0.2 to 0.8, and the one-dimensional diffusion (D1) has the highest fitting degree. The infrared heated technology effectively suppressed the secondary reaction of primary volatiles, and it presented a higher bio-oil yield than electrically heated technology, and as a result, the char and gas yields had a lower value. In both reactors, the yield of bio-oil increases at first and then decreases with the increase in temperature, and the bio-oil yield of the infrared heated furnace and electrically heated furnace reaches the maximum value at 550 ℃ and 500 ℃, which are 34.34 wt.% and 26.40 wt.%, respectively. The acids content of bio-oil decreased gradually with the temperature increased in the infrared heated reactor. The yield of phenolic compounds in bio-oil was higher in the former than in the latter, at 19.36 % and 14.86 %, respectively. The infrared heated reactor has superior performance in producing high quality bio-oils compared to conventional electric heating methods and may be considered as a promising biomass conversion technique.