Abstract
In this work, a continuous four day catalytic fast
pyrolysis experiment was carried out in VTT's Process
Development Unit (PDU) using pine sawdust and a spray
dried HZSM-5 catalyst. The PDU employs circulating
fluidized bed technology with online catalyst
regeneration. Approximately 250 kg of pyrolysis oil were
produced, along with 600 kg of aqueous side products. On
average, the carbon content of the pyrolysis oil was 72
wt. %, and the oxygen content 22 wt. %. The pyrolysis oil
contained 24 % of the original biomass carbon, whereas 14
% were present in the aqueous fraction. The catalytically
produced pyrolysis oil contained mostly water-insoluble
compounds, i.e. lignin-derived material and some aromatic
hydrocarbons, while majority of the polar oxygenates from
cellulose and hemicellulose concentrated in the aqueous
fraction. The elemental composition of the pyrolysis oil
remained quite stable during the four day experiment.
Clear changes were, however, observed in the properties
and behavior of the catalyst. Coke formation decreased
over time, as did the surface area and porosity of the
catalyst. This was accompanied by a loss of crystallinity
and changes in the catalyst structure. Biomass alkali
metals (Ca, K, Mg and P) also deposited on the catalyst,
and the overall alkali content of the catalyst reached
1.1 wt. % at the end of the experiment. A linear
correlation between catalyst alkali metal content and
acidity was observed, which suggested possible
substitution of HZSM-5 proton sites with biomass alkalis.
Original language | English |
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Publication status | Published - 2014 |
MoE publication type | Not Eligible |
Event | Symposium on Thermal and Catalytic Sciences for Biofuels and Biobased Products, TCS2014 - Denver, United States Duration: 2 Sep 2014 → 5 Sep 2014 |
Conference
Conference | Symposium on Thermal and Catalytic Sciences for Biofuels and Biobased Products, TCS2014 |
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Abbreviated title | TCS2014 |
Country | United States |
City | Denver |
Period | 2/09/14 → 5/09/14 |