Abstract
The aim of this study was to determine the yields and
chemical compositions of condensates formed at
torrefaction conditions with different kinds of
feedstocks and to assess their utilization from an
economic perspective. Test runs for spruce and bamboo
were carried out with a slow pyrolysis test rig, and the
liquids collected at 20-105, 105-240, and 240-300 °C
temperature ranges were analyzed for chemical
characteristics and compositions. The results were
compared with those obtained earlier for a birch
condensate. The mass yields and compositions of
condensates differed between the feedstocks and the
temperature ranges. The amount of organic compounds in
the total condensates was 12-19 wt %. The main compounds
were acetic acid, 1-hydroxy-2-propanone, methanol,
furfural, and 2-hydroxyacetaldehyde. Total condensates
formed at =280 °C are promising to be utilized for
different purposes, for example as a biopesticide. Higher
temperatures are critical, because at 290 °C, strong
exothermic reactions occur, which decreases considerably
the yield of torrefied material and produces tar
containing condensates. It is possible to produce, in
addition to biocoal, valuable liquids. Economic
assessments were performed for three torrefaction cases
without and with the recovery of condensates. The
production costs of torrefied pellets can be lowered
significantly, for example on the order of 5-10 MWh-1
in medium scale pellet production, by recovering and
selling the condensates to new applications.
| Original language | English |
|---|---|
| Pages (from-to) | 3134-3142 |
| Journal | Energy & Fuels |
| Volume | 29 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 2015 |
| MoE publication type | A1 Journal article-refereed |
Keywords
- torrefaction
- batch test rig
- wood
- bamboo
- condensates
- wood vinegar
- economic assessment