Comparative study of pyrolysis characteristics of bamboo powder and grape vine by anaerobic fermentation pretreatment

Abstract

To further explore the different effects of anaerobic fermentation on pyrolysis behaviors of grass and xylophyta, bamboo powder (BP) and grape vine (GV) were pretreated and pyrolysis characteristics were studied by thermogravimetric analysis (TG) and pyrolysis-gas chromatograph/mass spectrometry (Py-GC/MS) analysis. With the pretreatment time increasing from 0 to 20 days, cellulose contents in BP decreased from 51.47 to 48.52 wt.% and extractives contents increased from 5.58 to 11.57 wt.%. Only the extractives in GV were degraded during pretreatment. TG curves of BP moved to the higher temperature, which was contrary to that of GV. The residues at 700 °C from BP decreased from 25.11 to 16.9 wt.%, however that of GV increased. In the bio-oil of BP pyrolyzed at 500 °C, sugars contents firstly increased from 3.09 to 18.18% and then decreased; contents of linear acids and linear ketones decreased. The pretreatment improved significantly pyrolysis selectivity of BP for levoglucose (LG) and 4-vinyl phenol (4-VP). At 500 °C, LG content reached the maximum of 13.71% from the sample for 5 days. At 300 °C, 4-VP content reached the maximum of 16.16% from the sample for 20 days. Prolonging the pretreatment duration restrained the formation of LG and 4-VP. The bio-pretreatment increased the contents of linear carbonyls, linear acids and linear ketones in the GV bio-oil, but it decreased the sugars content especially LG.