Pyrolysis of C3 energy plant (arundo donax): Thermogravimetry, mechanism, and potential evaluation

Pyrolysis of Arundo donax can provide renewable and sustainable energy, materials, and chemicals in a large scale. In this study, the pyrolysis mechanism and potential evaluation of biomass was revealed by thermogravimetric analysis, Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry and a fixed bed pyrolysis setup. Up to about 150 degrees C, moisture in the sample was evaporated, resulting in mass loss. After drying, in the second stage, pyrolytic thermal decomposition reaction took place in the temperature range of about 150-375 degrees C at different heating rates ranging from 10 to 20 degrees C/min in inert atmosphere using the techniques of thermogravimetric analysis. The differential thermogravimetric curves could be divided into three fitting peaks corresponding to three key components of cellulose, hemicellulose, and lignin. Apparent absorbance peaks at 3590, 2950, 2182, 1786, and 1176 cm(-1) were detected and indicated the main pyrolysis products of CO2, CH4, CO, and O-containing compounds (acids, alcohols and ketones/aldehydes). The main carbon numbers were C-3, C-4, C-5, and C-8 and the main compositions were acids, ketones/aldehydes, alcohols, and phenols. The output of an industrial scale plant (2000 t/d) was 28MW power, 51.36 t/d bio-oil, 555.04 t/d vinegar, and 511.36 t/d biochar. In China, there are more than 0.3 million ha of marginal lands suitable for growing Arundo donax, which can provide 9 million tons of feedstock for industrial scale pyrolysis plants.