Pyrolysis and combustion characteristics of corncob hydrolysis residue

Corncob hydrolysis residue (CHR) is a by-product of the furfural industry. In this paper, the thermal behavior of CHR was determined with the aim to promote its application as fuels or chemicals. Firstly, the pyrolysis and combustion of CHR in nitrogen and air, were respectively investigated by thermogravimetric analyzer coupled with Fourier transform infrared spectrometer (TG-FTIR). The TG and DTG (differential thermos-gravimetric) curves revealed that both the pyrolysis and combustion of CHR included three distinct stages. The main evolving gaseous products during pyrolysis were H2O, CH4, CO, CO2 and oxygenated compounds, while combustion yielded considerable amounts of CO2 in the temperature range of 345-500 °C. The presence of oxygen can increase the volatilization rate of organic matter in CHR and accelerate thermal decomposition of CHR. A total weight loss of 57.29 wt% and 77.53 wt% was observed for pyrolysis and combustion, respectively. The non-isothermal kinetic was used to analyze the activation energy (E) of combustion and pyrolysis processes. The E of CHR pyrolysis reaction is 135.45 kJ mol−1 in temperature of 200-500 °C, while under the combustion process the value of E is 121.57 kJ mol−1 and 135.45 kJ mol−1 in 200-345 °C and 345-500 °C temperature ranges, respectively. In addition to it, the types of products and their proportions in pyrolysis process of CHR were studied by Py-GC/MS and the results indicated that the oxygenated compound produced from CHR pyrolysis mainly included acids, aldehyde, phenolics and anhydrides.