Upgrading Fuel Properties of Biomass by Torrefaction
Year: 2013
Type: article
Abstract: Torrefaction is a mild thermal (200 – 300 ÛC) treatment in an inert atmosphere, which is known to increase the energy density of biomass by evaporating water and a proportion of volatiles. In this work, the influence of torrefaction on the chemical and mechanical properties (grindability and hygroscopicity) of wood chips, wood pellets and wheat straw was investigated and compared. The mass loss during torrefaction was found to be a useful indicator for determining the degree of torrefaction. For all three biomass, higher torrefaction temperature or longer residence time resulted in higher mass loss, higher heating value, better grindability, and less moisture absorption. However, severe torrefaction conditions were found not necessary in order to save energy during grinding, since strain energy and grinding energy decreased tremendously in the first 5- 25 % anhydrous weight loss. By correlating the heating value and mass loss, it was found that wheat straw contained less heating value on mass basis than the other two fuels, but the fraction of energy retained in the torrefied sample as a function of mass loss was very similar for all three biomass. Gas products formed during torrefaction of three biomass were detected in situ by coupling mass spectrometer with a thermogravimetric analyzer (TGA). The main components were water, carbon monoxide, formic acid,
Authors: Lei Shang, Jesper Ahrenfeldt, Ulrik Birk Henriksen, Jens Kai Holm
Institution: Technical University of Denmark
Language: English
Subfield: Fuel Technology
Field: Energy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2605373009