Structural and chemical modifications of typical South African biomasses during torrefaction

Bioresour Technol. 2016 Feb:202:192-7. doi: 10.1016/j.biortech.2015.12.007. Epub 2015 Dec 14.

Abstract

Torrefaction experiments were carried out for three typical South African biomass samples (softwood chips, hardwood chips and sweet sorghum bagasse) to a weight loss of 30 wt.%. During torrefaction, moisture, non-structural carbohydrates and hemicelluloses were reduced, resulting in a structurally modified torrefaction product. There was a reduction in the average crystalline diameter (La) (XRD), an increase in the aromatic fraction and a reduction in aliphatics (substituted and unsubstituted) (CPMAS (13)C NMR). The decrease in the aliphatic components of the lignocellulosic material under the torrefaction conditions also resulted in a slight ordering of the carbon lattice. The degradation of hemicelluloses and non-structural carbohydrates increased the inclusive surface area of sweet sorghum bagasse, while it did not change significantly for the woody biomasses.

Keywords: Biomass; CP-MAS (13)C NMR; Torrefaction; XRD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomass*
  • Carbohydrates / analysis
  • Carbon / analysis
  • Cellulose / chemistry*
  • Hot Temperature*
  • Lignin / analysis
  • Magnetic Resonance Spectroscopy
  • Sorghum / chemistry
  • South Africa
  • Thermogravimetry
  • Wood / chemistry*

Substances

  • Carbohydrates
  • lignocellulose
  • Carbon
  • Cellulose
  • Lignin
  • bagasse