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To explore the changes of pyrolysis behaviors from xylophyta to herbage, pyrolysis properties of red pepper stalks (RPS) as a representative kind of biomass of high lignin content of agricultural residues were studied by using TGA and Py-GC/MS. The results indicated that contents of cellulose, 43.2 wt.%, and of lignin, 24.7 wt.% were higher than those of corn stalks, wheat stalks and cotton stalks, but closer to those of the poplar wood. The pyrolysis process mainly occurred in three stages, and with an increasing heating rate from 10 °C/min to 30 °C/min, the TGA curves shifted to a lower temperature. With an increase in pyrolysis temperature, the contents of sugars, phenols and furans decreased from 3.96%, 13.54% and 10.13% to 1.09%, 7.13% and 1.65%, respectively. The contents of hydroxyacetaldehyde and acetone reached a maximum 13.71% and 20.05% at 500 °C. At 300 °C levoglucose, pentanal and methyl furan content reached maxima of 3.63%, 13.09% and 7.49%, respectively. Different chemical components could account for the changes of pyrolytic behaviors from xylophyta to herbage. [ABSTRACT FROM AUTHOR]

To utilized biomass for optimum application, sweet potato vine (SPV) was studied on its pyrolytic characteristics by TGA and Py-GC/MS analysis as a representative of biomass with low lignin content and high extractives content. Results indicated that lignin, cellulose, hemicellulose and extractives contents were 7.85 wt.%, 33.01 wt.%, 12.25 wt.% and 37.12 wt.%, respectively. In bio-oil, sugars content firstly increased from 8.76 wt.% (350 °C) to 13.97 wt.% (400 °C) and then decreased to 9.19 wt.% (500 °C); linear carbonyls and linear acids contents decreased from 16.58 wt.% and 17.45 wt.% to 5.26 wt.% and 4.03 wt.%, respectively; furans content increased from 7.10 wt.% to 15.47 wt.%. The content 11.86 wt.% of levoglucose at 400 °C, 15.41 wt.% of acetic acid at 350 °C and 6.94 wt.% of furfural at 500 °C suggested good pyrolysis selectivity of SPV. [ABSTRACT FROM AUTHOR]