Effect of torrefaction temperature and O2 concentration on the pyrolysis behaviour of moso bamboo

Abstract

Five-year-old moso bamboo was torrefied under nitrogen and different oxygen concentrations of 3% to 9% and torrefaction temperatures of 200 °C to 300 °C. Mass yields of 31.7% to 96.6%, energy yields of 30.8% to 98.9%, and higher heating values (HHVs) in the range 18.8 to 27.1 MJ/kg were obtained. The torrefied sample was characterized by Fourier transform infrared spectrometry (FTIR). Under the different torrefaction temperatures and oxygen concentrations, hemicellulose and cellulose were thermally decomposed, which led to significant changes in the chemical functional groups of the raw and torrefied bamboo. The pyrolysis experiments on raw and torrefied bamboo were conducted using the pyrolyzer coupled with a gas chromatography/mass spectrometer (Py-GC/MS). According to the Py-GC/MS analysis, the pyrolytic bio-oil were mainly composed of acids, furans, phenols, ketones, aldehydes, esters, alcohols, and hydrocarbons. Higher torrefaction temperature reduced the relative contents of acids, ketones, furans, and aldehydes. However, lower torrefaction temperatures and moderate oxygen concentrations were optimal for the production of phenols and hydrocarbons.

Evaluation of the Optimal Conditions for Oxygen-Rich and Oxygen-Lean Torrefaction of Forestry Byproduct as a Fuel

“…Contrary to this popular view, Basu et al reported that the effect of oxygen concentration on the calorific value of torrefied biomass products is marginal [27]. Sun et al reported that torrefaction temperature and oxygen concentration significantly influenced bamboo pyrolysis [28].…”

Identification of differences and comparison of fuel characteristics of torrefied agro-byproducts under oxidative conditions

“…Basu et al reported that the effect of oxygen concentration on the heating value of a torrefied biomass product is marginal [ 23 ]. Otherwise, Sun et al reported that torrefaction temperatures and oxygen concentrations remarkably influenced the pyrolysis of bamboo [ 26 ]. Wang et al [ 27 ] reported moderate and severe removal of hemicellulose can be achieved through torrefaction under air and nitrogen, respectively.…”