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Advanced biofuels via synthesis gas
Fischer-Tropsch Synthesis Over Cobalt Catalysts:
Biomass Conversion to Fuels
Edd A. Blekkan
Dep. of Chemical Engineering,
Norwegian University of
Science and Technology
(NTNU), NO-7491 Trondheim,
Norway
Bioenergi søkerseminar
14.mars 2014
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Synthesis Gas
Feedstocks and Products
Coal
H2 (or NH3)
CH4
Gas
Synthesis Gas
(CO+H2)
CH3(CH2)nCH3
Oil
CH3OH
Biomass
CH3(CH2)nCH2OH
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BTL
Figure: Kavalov B, Peteves SD, 2005.
(EU report, ISBN 92-894-9784-X )
•
•
GTL, CTL are established technologies
BTL introduces other issues
– Economy of scale
– Biomass contains a range of elements, cleaning/scrubbing at low temperature has a
cost
• Investment
• Efficiency
•
Recent review: Lillebø, Holmen, Enger, Blekkan, WIREs Energy and Environment,
Vol. 2 (2013), 507. (DOI:10.1002/wene.69)
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Effect of alkali
• Alkali species are important in syngas from
biomass and coal gasification
– Concentration and speciation depends on conditions
and composition (Norheim et al.)
– In case of poor design or operation of gas cleaning
units alkali species can reach catalytic reactors
• Sodium can be present in alumina support
materials, and has been shown to influence
specific activity strongly (Borg et al.).
A. Norheim et al. /Energy & Fuels 23 (2009) 920–925
Ø. Borg et al. / Journal of Catalysis 279 (2011) 163–173
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Catalytic activity
• Even low concentrations lead to large loss in activity
• Gas cleaning crucial stage in the process
-Lillebø, Patanou, Yang, Blekkan, Holmen, Catalysis Today, 215 (2013), 60.
-Patanou, Lillebø, Yang, Chen, Holmen, Blekkan, Industrial & Engineering
Chemistry Research, 53 (2014) 1787−1793.
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Utfordringen
• Big is «beautiful»
• Pearl, Qatar
(Shell & QP)
– 140 000 fat/dag
– 20 milliarder US $
– «Gratis» naturgass
• Biomasse som
råstoff krever
andre løsninger
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Microstructured reactors in FTS?
• Microstructured reactors:
– Large number of small, parallel channels
• enhanced mass transfer properties
• intensified heat transfer
– Different production technologies for
these systems
– Compact and modular
• Suggested for offshore use, BTL, biogas
conversion etc.
• New paradigm in scaling?
• Suitable for FTS?
– Catalyst introduction
• Wall coating
• Packed bed
• Structured systems
– Pressure drop and stability issues?
• Companies claim good results
– Oxford catalyst (Velocys) recipient of
2010 XTL award for their system
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Micro-channelled
reactor
Steel microstructured reactor (KIT,
Karlsruhe)
– 8 sections with 800 μm channel height
– Channels formed by stacking of foils etched
with a pillar structure
– Cross-flow oil-channels between catalyst
layers (cooling)
– Unit (2 cm3) placed in tube fitting
– Filled with catalyst (high loading Co/Al2O3,
particle size 53-75 μm
– Compared with same catalyst in FBR (diluted
1:20 with SiC to ensure uniform temperature,
Δ <1 K
Myrstad et al. Catalysis Today 147S (2009) S301.
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Microchannelled system compared to FBR
•
•
•
The catalyst activity and selectivity is comparable in the two systems
T measurements indicates some axial gradient, probably due to the effect of
heat loss to surroundings (modelling indicates isothermal operation)’
No increased deactivation even at 240 ºC confirms isothermal operation
Myrstad et al. Catalysis Today 147S (2009) S301.
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Oppsummering
• Prosjektene våre bygger på kompetanse etablert for
å konvertere naturgass
• Biomasse som råstoff krever store justeringer
– Fordi kjemien er litt forskjellig og stiller andre krav
• Jeg har snakket om alkali, men det er flere problemer som må løses
– Andre økonomiske vilkår
• Stordriftsfordel – tilgang på råstoff