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
Monocrystalline silicon thin film for cost-cutting solar cells with 10-times faster growth rate fabricated
16.03.2018 | Tokyo Institute of Technology
Research gets closer to producing revolutionary battery to power renewable energy industry
15.03.2018 | University of Kansas
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.
When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...
At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.
Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...
16.03.2018 | Event News
13.03.2018 | Event News
08.03.2018 | Event News
16.03.2018 | Earth Sciences
16.03.2018 | Physics and Astronomy
16.03.2018 | Life Sciences