March 10, 2012, London, UK - Scientists at Imperial College London have demonstrated that a key part of biomass processing could be made 80 per cent more energy-efficient by taking advantage of the slippery properties of fluids called ionic solvents.
By Scott Jamieson
They say this could reduce the cost of biofuels by 3p per litre, around
10% of its current cost. 
The efficiency savings can be made
during one of the energy-intensive stages of the biomass manufacturing
process, when solid timber chunks are turned into a 'soup' of fluids and fine wood particles
in an industrial grinder, which works in a similar way to a giant
coffee grinder. The discovery paves the way to making the biomass
Treating timber with ionic solvents has
previously been shown to help processing wood into biofuels and
chemicals. While initially this effect was only attributed to the
solvents' ability to partially weaken wood's tough, fibrous structure,
this new study suggests the energy-savings are predominantly due to the
way that these fluids lubricate the wood chips as they go around in the
Lead author of the study Dr Agnieszka Brandt, from the
Department of Chemistry at Imperial College London, said: "Tree wood is a
mine of really valuable chemicals locked up in a safe that we need to
unlock before we can use the different components. Breaking down the
timber into a fine powder helps us to access these chemicals, but it
needs to be an energy-efficient process to make it sustainable. Our
previous work showed how the chemical action of ionic solvents improved
energy efficiency in the processing, but we were surprised to discover
how much more energy could be saved when take advantage of their
lubricating physical properties."
biomass products are often hailed as environmentally friendly
alternatives to fossil fuel and its derivatives. Trees such as fast
growing species of willow and pine will be an important source of
biofuels and basis for manufacturing naturally occurring chemicals like
vanillin (a flavouring in the food industry), valuable oils and
biomass-derived plastics, such as polystyrenes or polyesters (used for
plastic bottles). Scientists are working to ensure biomass lives up to
these expectations, assessing and reducing the environmental impact of
every part of the product cycle, including the source of its raw
materials, how and where they are transported, and what happens to the
by-products of the industry.
Research author Tom Welton, Professor of Sustainable Chemistry
and Head of Imperial’s Department of Chemistry, said: "Sustainable
development has been defined by the UN as development to meet the needs
of the present generation without compromising the ability of future
generations to meet their own needs.
"The alleviation of poverty
and improvement of all of our living standards cannot continue without
us also ensuring that our planet is in a condition to support these. As
our petrochemical resources run out and we need to turn to other places
for our energy and materials needs, we have an opportunity to build
these new industries in a sustainable way. This is an opportunity that
we can’t afford to miss."
 Calculating the cost-saving in biomass manufacturing
- The estimated grinding cost of grinding biomass is £8 per tonne. This method would reduce that by 80%, which is £6.40/tonne.
- Each tonne of biomass produces about 200L of ethanol
- This is a saving approximately 3p per litre off the cost of ethanol
- Ethanol costs just about £0.30 per litre, so this reduces prices by ca. 10%
 Photograph shows ground wood
chips after treatment at 90 °C for 1 h with various ionic solvents and
other liquids: (a) no liquid, (b) Organosolv, (c) DMSO, (d) silicone
oil, (e) [C4C1im][HSO4], (f ) [C4C1im][MeCO2], (g) [C4C1im][NTf2], (h) Fomblin.