Hydrogen has been tipped as a cleaner, greener alternative to fossil fuels. But scientists have struggled to find a way to make it that doesn't consume vast amounts of energy, use up scarce natural resources, or spew out high levels of greenhouse gas.
Researchers at the University of Leeds have now found an energy-efficient way to make hydrogen out of used vegetable oils discarded by restaurants, takeaways and pubs. Not only does the process generate some of the energy needed to make the hydrogen gas itself, it is also essentially carbon-neutral.
"We are working towards a vision of the hydrogen economy," said Dr Valerie Dupont, who is leading the Leeds-based project. "Hydrogen –based fuel could potentially be used to run our cars or even drive larger scale power plants, generating the electricity we need to light our buildings, run our kettles and fridges, and power our computers. But hydrogen does not occur naturally, it has to be made. With this process, we can do that in a sustainable way by recycling waste materials, such as used cooking oil."
Hydrogen can already be made quite easily from simple fossil fuels, such as natural gas. The fuel is mixed with steam in the presence of a metal catalyst then heated to above 800 degrees centigrade to form hydrogen and carbon dioxide.
However when much more complex fuels are used, such as waste vegetable oil, it is difficult to make very much hydrogen using this method without raising the temperature even further. The reactions could be run at lower temperatures but the catalysts would quickly become poisoned by residues left over from the dirty oil. In short, the process is not only expensive but also environmentally unsound.
Dr Dupont and colleagues have perfected a two-stage process that is essentially self-heating. To begin, the nickel catalyst is blasted with air to form nickel oxide – an 'exothermic' process that can raise the starting temperature of 650 degrees by another 200 degrees. The fuel and steam mixture then reacts with the hot nickel oxide to make hydrogen and carbon dioxide.
The researchers also added a special 'sorbent' material to trap all the carbon dioxide produced, leaving them with pure hydrogen gas. This trick eliminated the greenhouse gas emissions and also forced the reaction to keep running, increasing the amount of hydrogen made.
"The hydrogen starts to be made almost straight away, you don't have to wait for all of the catalyst to be turned into pure nickel," Dr Dupont said. "So as well as the generation of heat, this is another way that makes the process very efficient."
The researchers have shown that the two-stage process works well in a small, test reactor. They now want to scale-up the trials and make larger volumes of hydrogen gas over longer periods of time.
"The beauty of this technology is that it can be operated at any scale. It is just as suitable for use at a filling station as at a small power plant," Dr Dupont said. "If we could create more of our electricity locally using hydrogen-powered fuel cells, then we could cut the amount of energy lost during transmission down power lines."
Details of the work will be published in the journal Bioresource Technology.
The project was funded by the Engineering and Physical Sciences Research Council (EPSRC) and benefited from industrial collaboration with Johnson Matthey.
For further information: Paula Gould, University of Leeds press office: Tel +44 113 343 8059, email firstname.lastname@example.org
Notes to editors:
1. The paper: Pimenidou P, Rickett G, Dupont V, Twigg MV, 'High purity H2 by sorption-enhanced chemical looping reforming of waste cooking oil in a packed bed reactor', is available online ahead of print publication in Bioresource Technology (doi:10.1016/j.biortech.2010.06.079).
2. The Faculty of Engineering at the University of Leeds was ranked seventh overall in the UK in the 2008 Research Assessment Exercise (RAE), with 75% of its activity rated as 'internationally excellent' or 'world leading'.
The University of Leeds is one of the largest higher education institutions in the UK and a member of the Russell Group of research-intensive universities. The University's vision is to secure a place among the world's top 50 by 2015. www.leeds.ac.uk
3. The Engineering and Physical Sciences Research Council (EPSRC) is the UK's main agency for funding research in engineering and the physical sciences. The EPSRC invests around £850 million a year in research and postgraduate training, to help the nation handle the next generation of technological change. The areas covered range from information technology to structural engineering, and mathematics to materials science.
Paula Gould | EurekAlert!
Further reports about: > Bioresource > EPSRC > Hydrogen > Physical Sciences > carbon dioxide > fossil fuels > greenhouse gas > greenhouse gas emission > hydrogen gas > information technology > natural resource > nickel oxide > power plant > two-stage process > vegetable oil > waste management > waste material
Waste from paper and pulp industry supplies raw material for development of new redox flow batteries
12.10.2017 | Johannes Gutenberg-Universität Mainz
Low-cost battery from waste graphite
11.10.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Earth Sciences
20.10.2017 | Life Sciences
20.10.2017 | Life Sciences