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Recent progress in the
thermocatalytic processing of
biomass into advanced biofuels
David Serrano
Rey Juan Carlos University, IMDEA Energy Institute
Biofuels2015, Valencia, August 2015
World biofuels production (Mtoe)
2014 figures (BP statistical review of world energy, 2015):
• Global growth in primary energy consumption: 0.9%
• Biofuels production growth: 7.4%
Hindrances for the commercial deployment of
first generation biofuels
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Negative effects on the food market and prices.
Deforestation and land use changes.
Environmental impact: uncertain reduction of CO2 emissions, water consumption.
Limits in the proportion they can be incorporated into conventional engines.
Production costs: 2-3 times higher than those of petroleum fuels (high cost of both
the raw biomass and the conversion process).
BP Energy Outlook 2035 (2015): Transport sector
sector
Second generation biofuels
Third generation biofuels
Biofuels from microorganisms
Microalgae
Macroalgae
Cyanobacteria
Oleaginous
yeasts
Genetic engineering for biofuels production
F. Sarkeyeva et al., Photosynth.. Res. 125 (2015) 329-340.
Advanced biofuels
• Production from non-food related raw materials:
Lignocellulose, residues, microorganisms.
• Properties close to those of conventional fossil fuels:
low oxygen content, high heat value, preferred as
liquids.
• Deep transformation of the raw biomass resources:
integration into biorefineries.
• Co-production of biofuels and bio-chemicals.
Potential of lignocellulosic biomass resources in Europe
By 2030 about 1/3 of the
energy consumed in
transport could be
covered by the European
bioenergy sector.
A. Sanna, Bionerg. Res. 7 (2014) 36-47.
Transgenic woody plants for biofuel production
• Genetic modification of forest trees is being investigated to improve
their properties:
- Fast growing trees.
- Higher cellulose content (for bioethanol production)
- Improved properties: insect and herbicide resistance, salt and
frost tolerance, etc.
• Hazards: transfer of the synthetic genes to other plant species, risks
for human health.
W. Tang et al., J. For. Res. 25(2) (2014) 225-236.
Lignocellulose conversion routes into
biofuels
A. Sanna, Bionerg. Res. 7 (2014) 36-47.
Lignocellusose conversion into advanced biofuels
Main modifications of the biomass
components:
• Oxygen removal
• Increase of the hydrogen content
• Improvement of the heat value
• Depolymerization followed by CC bonds formation
Liquefaction
• Hydrothermal treatment of biomass
(200 – 370ºC, 100 – 200 atm) in
aqueous media.
• Production of a hydrophobic bio-oil:
great part of the oxygen is removed
by dehydration and decarboxylation
reactions.
• Use of both homogeneous and
heterogeneous catalysts.
• High operation and plant investment
costs.
• Convenient treatment for biomass
with high water content, like
microalgae.
Gasification + Fischer Tropsch
• Adaptation of the technology initially
developed for coal: partial oxidation,
leading to syngas (CO and H2).
• Reaction conditions: T > 800 ºC, using
oxygen, air, steam or mixtures as
gasifying agent.
• Use of catalysts in the FT step: mainly
Co and Fe containing catalysts.
• The gaseous stream must be
subjected to exhaustive cleaning
before the FT step to remove
particulates, tars, alkali, nitrogen and
sulphur.
• Novel catalysts have been proposed to
reduce tars and coke formation.
Gasification + Fischer Tropsch (BTL)
• Corrosion and fouling of heat
exchangers.
• High complexity and costs
(both operation and
investment).
• Scale economy: plants of
higher capacity, co-processing.
Pyrolysis
H2, CO, CO2, H2O, CH4, C2H2, C2H4
Pyrolysis
Lignin + Cellulose + Hemicellulose
Lignocellolose Biomass
Gas (10-35 %)
Bio-oil (10-75 %)
Oxygenated organics, hydrocarbons,
water, tars
Char (10-35 %)
Fixed carbon, volatile material, ash
Thermal treatment in inert
atmosphere.
Main parameters:
• Temperature-time
• Heating rate
• Reactor type
• Biomass pre-treatment
Commercial process of biomass pyrolysis
(Joensuu, Finland)
Capacity: 50.000 t/y of bio-oil
• Compared to gasification
and liquefaction, pyrolysis
is the cheapest technology
requiring the lowest capital
investment.
• The produced bio-oil can be
competitive even with
petroleum-derived fuels
provided that biomass is
available.
Lignocellulose pyrolysis: bio-oil composition
O
O
H3C
H3C
OH
Ethanol
H3C
OH
Alcohols
Acetic acid
CH3
propan-2-one
Acids
Ketones
O
HO
H3C
O
Hydroxymethylfurfural
H3C
O
Furans
OH
O
Aldehydes
Organic
compounds
in Bio-oils
Syringols
acetaldehyde
OH
Phenols
CH3
Syringol
O
phenol
Guaiacols
O
CH3
OH
Sugars
Misc.Ooxygenates
O
O
OH
HO
OH
OH
Guaiacol
Levoglucosan
H3C
Hydroxyacetone
Catalytic bio-oil upgrading
Future perspectives and challenges
Thermocatalytic processes will play a relevant role in the
commercial deployment of advanced biofuels, but this will still
require to successfully face a number of challenges.
• More accurate estimation of the potential of lígnocelllusic resources.
• Genetic engineering is a powerful tool for improving biofuels-producing
microorganisms and woody plants.
• Liquefaction: new catalysts for conversion of high-water content biomasses.
• Gasification: co-processing with other materials to reduce costs.
• Pyrolysis: Improvement of bio-oil properties by catalytic upgrading.
Thanks for your
kind attention