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%

• 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).

Hindrances for the commercial deployment of first generation biofuels

BP Energy Outlook 2035 (2015): Transport sector sector

Second generation biofuels

Biofuels from microorganisms

Third generation biofuels

Genetic engineering for biofuels productionF. Sarkeyeva et al., Photosynth.. Res. 125 (2015) 329-340.

Microalgae

Macroalgae

Oleaginous yeasts

Cyanobacteria

• 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.

Advanced biofuels

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.

Main modifications of the biomass components:

• Oxygen removal

• Increase of the hydrogen content

• Improvement of the heat value

• Depolymerization followed by C-C bonds formation

18 MJ/kg

43 MJ/kg

Lignocellusose conversion into advanced biofuels

20 MJ/kg

27 MJ/kg

• 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.

Liquefaction

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.

Fixed carbon, volatile material, ash

H2, CO, CO2, H2O, CH4, C2H2, C2H4

Oxygenated organics, hydrocarbons, water, tars

Lign

ocel

lolo

se B

iom

ass

Lign

in +

Cel

lulo

se +

Hem

icel

lulo

se

Pyro

lysi

s

Gas (10-35 %)

Bio-oil (10-75 %)

Char (10-35 %)

Thermal treatment in inert atmosphere.

Main parameters:

• Temperature-time

• Heating rate

• Reactor type

• Biomass pre-treatment

Pyrolysis

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.

Organic compounds in Bio-oils

O

OH

OH

OH

O

Levoglucosan

OH

CH3O

G uaiacol

AcidsAlcohols

O

OH

CH3

Acetic acid

CH3 OH

Ethanol

Ketones

O

CH3CH3

propan-2-one

AldehydesOCH3

acetaldehyde

Phenols

OH

phenol

Guaiacols

Syringols

Sugars

Furans

Misc. oxygenates

OH

O

CH3

OCH3

O

OH

CH3

Hydroxyacetone

OOH O

Hydroxymethylfurfural

Syringol

Lignocellulose pyrolysis: bio-oil composition

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