Grass clippings: the fuel of tomorrow?

Posted on 16 March 2010

Researchers at the University of York are developing novel ways of using microwaves to convert waste products such as grass cuttings or straw into biofuels.

Using a Biorefinery Microwave Demonstrator, scientists in the University’s Green Chemistry Centre (GCC) are aiming to change the future of world energy production.

The Centre is embarking major new projects on fast low temperature pyrolysis - the heating of material in the absence of air for making of higher energy density products, such as charcoal - for the production of liquid fuels and high calorific value chars for use in power stations.
The Green Chemistry Centre of Excellence has been studying the effects of microwave radiation on chemical compounds, giving new insights into how it can accelerate chemical reactions. The centre has discovered that microwaves can be used to selectively activate components of biomass, such as trees, grasses, crops, paper and food waste, to control the decomposition process.

Through careful tuning of conditions the product output can be switched between high value chemicals, bio-oils for blending with petroleum for use in cars and bio-chars for co-firing with coal power stations making a contribution towards reducing Britain’s carbon dioxide emissions in line with government targets.

It means that green chemical technology can be used to make a range of valuable products including liquid and solid fuels, and chemicals from sustainable sources of carbon. A major feature of this is designing and building new continuous microwave biomass processors.

Green Chemistry Centre Director Professor James Clark said “Nature has pyrolysed plant material and other biomasses very slowly at low temperatures for millions of years to make fossil fuels. Man has pyrolysed biomass quickly at very high temperature to make charcoal for hundreds of years. Now, we are looking at the next generation by carrying out pyrolysis rapidly at low temperatures to make a range of fuel products.”

Funding of more than £1.5 million for the research has come from the European Regional Development Fund, the Carbon Trust and METRC (The N8 Molecular Engineering Translational Research Centre).