Gas composition from Biomass Torrefaction

1
Gas composition from Biomass Torrefaction Linda
Pommer1, Lorenz Gerber2, Susanne Wiklund
Lindström1, Ingemar Olofsson1, Anders Nordin1
1 Energy Technology and Thermal Process
Chemistry, Umeå University, Sweden 2 Department
of Forest Genetics and Plant Physiology, Swedish
University of Agricultural Sciences, Sweden
Background Biomass is a widespread source of
renewable energy, and has the potential to play a
significant role in the energy conversion
decreasing the fossil fuel dependency. However, a
number of fuel characteristic properties could be
significantly improved.
Torrefaction pyrolysis-GC/MS Raw pulverized
biomass samples were torrefied in a Py-GC/MS. Two
different heating rates were used (1) heating of
the biomass to 300 ºC during 10 min, and (2)
heating to 300 ºC during 5 s.
Results The composition of the products gas were
determined using both Py-GC/MS and MBMS. The
compounds present at the highest concentrations
are presented in the table below.
Figure 2. Weighs selected for analysis of
separating compounds between hardwood and
softwood.
Identification of compounds in the product gas
separating hardwood from softwood Mass numbers
selected from PLS-DA consisted mainly of
compounds derived from lignin. Compounds
correlated to hardwood were products derived from
S-lignin and for softwood from G-lignin.

• The knowledge of the composition of volatiles
  produced in the temperature range of torrefaction
  is a topic of interest for
• Producing green chemicals
• Energy process- and exergy optimization
• Process behavior and operation
• Raw material adaption process
• Process control

Energy content of the product gas Compounds in
the product gas were tentatively identified and
quantified. The results are preliminary and
indicate a higher HHV (Higher Heating Value) for
the product gas during torrefaction of Birch.
Differences in the contri-bution to the HHV from
of specific compounds could be attributable to
dissimilarities of softwood and hardwood.
Objective The objective with the present work was
therefore to determine the composition and the
energy content of the product gas from
torrefaction utilizing different biomasses.
Multivariate analysis All responses from MBMS
measurements of the different samples were used
for both PCA and PLS-DA. In the PLS-DA presented
below the data was centered and UV scaled for
identification of to components correlated to
coniferous or deciduous wood independent on
concentrations.
Torrefaction MBMS analysis
Figure 3. Higher heating value of wet
torrefaction product gas.
Chips from Birch, Pine and Spruce were torrefied
at 270-320 ºC. Initially the wood chips were
pre-dried in 105ºC over night before it was
intro-duced into a heated alumina reactor tube.
The size of the wood chips torrefied were 20 x 7
x 3 mm. The wood chips were immersed down
through the reactor to stages for initial drying
(100ºC) and torre-faction (275-315 ºC). The
biomass was exposed to torrefaction condi-tions
for 20-50 min. The produced gases were
continuously sampled by a molecular beam mass
spectro-meter (MBMS).
Figure 4. Relative contribution to higher heating
value in torrefaction product gas.
Suggestion of compounds based on fragmentation
and base peaks from the literature.
Energy Technology and Thermal Process
Chemistry Umeå University SE-901 87 Umeå,
Sweden Phone [phone] E-Post
linda.pommer_at_chem.umu.se
linda.pommer_at_chem.umu.se
lorenz.gerber_at_genfys.slu.se
susanne.wiklundlindstrom_at_chem.umu.se
anders.nordin_at_chem.umu.se