Millions of tons of toxic ash are created every year from the burning of refuse. This potentially-dangerous material is typically simply dumped in landfills (or, in some countries, used in construction). Rather than simply discard this toxic material, why not do something useful with it? And that’s exactly what researchers at Lund University have done. Researchers there have developed a process to produce hydrogen gas from the ash.
The technique appears to have great potential: “20 billion litres of hydrogen gas a year, or 56 gigawatt-hours (GWh). Calculated as electricity, the energy is the equivalent of the annual needs of around 11 000 detached houses.”
Hydrogen gas has been emerging as an potentially very important energy source in recent years, primarily because of its portability and ease of storage. And with how widespread refuse incineration is in Europe, there’s great potential there.
“The ash can be used as a resource through recovery of hydrogen gas instead of being allowed to be released into the air as at present. Our ash deposits are like a goldmine,” said Aamir Ilyas, Doctor of Water Resources Engineering at Lund University and the developer of the technique.
The technique is rather simple:
[It] involves placing the ash in an oxygen-free environment. The ash is dampened with water, whereupon it forms hydrogen gas. The gas is sucked up through pipes and stored in tanks. It is the heavy, grit-like bottom ash that is used. In combustion, a lighter fly ash is also formed. The bottom ash remains in quarantine, in the open air, at the site for up to six months to prevent leaching of environmentally harmful metals and the risk of hydrogen gas being formed, since accumulation of hydrogen during indoor storage can result in explosion.
A bonus is that this method removes the risk of hydrogen gas. It also reduces the strain on our landfill sites.
In reference to why this new technique is important even with the rapid growth of solar and wind energy in recent years, Kenneth M. Persson, Professor of Water Resources Engineering, had this to say: “There will not be one universal solution that will be used to generate energy. We need to find a number of solutions.”
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