Where there is muck there is brass

Interdisciplinary research at Leeds is finding ways of processing and reusing waste to create new products and alternative energy sources. Professor Paul Williams, Head of the Faculty’s Energy and Resources Research Institute, leads a group which is looking at how different types of waste can be recycled to create a new product or energy.

“We are constantly looking for ways to reduce emissions, reduce the physical amount of waste being produced and create something new out of this waste”, says Professor Williams.

The work undertaken relating to the breaking down of worn-out tyres clearly illustrates Professor Williams’ point. The system created by Professor Williams is a refinement of the pyrolysis process which causes the molecular structure of the tyre to break down, leaving behind oil, gas and carbon. The gas is then used to power the process, making it a self-sustaining method of tyre disposal. The oil can be used as a fuel or upgraded to a chemical feedstock. The carbon can also be upgraded to produce activated carbon.

Professor Williams goes on to say “One of the difficulties in getting rid of waste through traditional incineration processes is that it can emit harmful dioxins into the air. Dioxins are toxic and are thought to be linked to cancer, other serious illnesses and birth defects, so much of our current work is focusing on getting rid of waste, whilst reducing dioxin levels during incineration.”

The group have so far secured two grants from the Engineering and Physical Sciences Research Council (EPSRC): £220,000 in 2003 to examine and analyse the release of dioxins into flue gases through the incineration process and, £245,000 in 2006 to look at how dioxins are formed and how they can be minimised.

In 2006, the Energy and Resources Research Institute was also awarded a £293,000 grant to research the burning of tyres and plastics in power stations. The University is partnering with energy supplier E.ON, which is supplying fuels and undertaking some of the analysis of the resultant ash. The Institute is proposing adding granulated tyres at a later stage of the combustion process in the hope of reducing nitrogen oxide emissions. The pilot scale results have so far shown some exciting outcomes and could make a significant impact on the growing ‘tyre mountain’.