Leeds researchers produce biohydrogen from biodiesel byproduct glycerol

Scientists at the University of Leeds have found a novel, efficient process to turn low-grade glycerol sludge obtained from biodiesel production into a high-value hydrogen rich gas. The process could make eco-friendly biodiesel even greener and more economical to produce, while at the same time opening a viable production pathway for hydrogen. Given that the gas is produced from a renewable, bio-based feedstock, it can effectively be called 'biohydrogen'.

Biodiesel – motor fuel derived from vegetable oil - is a renewable alternative to rapidly depleting fossil fuels. It is biodegradable and non-toxic, and production is on the up. But for each molecule of biodiesel produced, another of low-value crude glycerol (glycerin) is generated. Its disposal presents a growing economic and environmental problem. When vegetable oils are transesterified, around 10% of the volume becomes glycerin. This has led to a glut of crude glycerol on the market. Many researchers are therefor looking for novel applications for the product: some have found cost-effective ways to use crude glycerin as feedstock for new types of biopolymers, bioplastic films, and green specialty chemicals such as propylene glycol. Others found glycerin makes for a suitable cattle and poultry feed or for the production of biogas. Still others recently found a way to turn it efficiently into ethanol.

Now researchers from Leeds have shown how glycerol can be converted to produce a hydrogen rich gas. Hydrogen is in great demand for use in fertilisers, chemical plants and food production. Moreover, hydrogen is itself viewed as a future ‘clean’ replacement for hydrocarbon-based transport fuels, and most countries currently reliant on these fuels are investing heavily in hydrogen development programmes.

The novel process developed by Dr Valerie Dupont and her co-investigators in the University's Faculty of Engineering mixes glycerol with steam at a controlled temperature and pressure, separating the waste product into hydrogen, water and carbon dioxide, with no residues. A special absorbent material filters out the carbon dioxide, which leaves a much purer product.

Hydrogen has been identified as a key future fuel for low carbon energy systems such as power generation in fuel cells and as a transport fuel. Current production methods are expensive and unsustainable, using either increasingly scarce fossil fuel sources such as natural gas, or other less efficient methods such as water electrolysis.

Our process is a clean, renewable alternative to conventional methods. It produces something with high value from a low grade by-product for which there are few economical upgrading mechanisms. In addition, it’s a near ‘carbon-neutral’ process, since the CO2 generated is not derived from the use of fossil fuels. - Dr Valerie Dupont

Dr Dupont believes the process is easily scalable to industrial production, and, as the race towards the ‘hydrogen economy’ accelerates, could potentially be an economically important, sustainable – and environmentally friendly – way of meeting the growing demand for hydrogen. Whilst it is likely to be many years before a full hydrogen economy can be achieved due to infrastructure and storage issues, biodiesel is a forerunner to this as a sustainable, more environmentally friendly fuel, to be used in combustion engines:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: biodiesel :: byproduct :: glycerin :: hydrogen :: biohydrogen ::

Hydrogen production is a large and growing industry. Globally, some 50 million metric tons of hydrogen, equal to about 170 million tons of oil equivalent, were produced in 2004. The growth rate is around 10 per cent per year. In the United States, 2004 production was about 11 million metric tons (MMT), an average power flow of 48 gigawatts. For comparison, the average electric production in 2003 was some 442 gigawatts. As of 2005, the economic value of all hydrogen produced worldwide is about $135 billion per year.

Dr Dupont’s research has been funded with a £270k grant from the Engineering and Physical Sciences Research Council (EPSRC) under the Energy programme, and is in collaboration with Professors Yulong Ding and Mojtaba Ghadiri from the Institute of Particle Science and Engineering, and Professor Paul Williams from the Energy and Resources Research Institute at the University.

Industrial collaborators are Johnson Matthey and Jatropha biodiesel producer D1-Oils.

Dr Valerie Dupont is a senior lecturer in the Energy & Resources Research Institute (ERRI) in the Faculty of Engineering. Her research interests span combustion and fuel engineering, fuel science and technology, by-products relating to fuels, the chemistry of catalysis and energy and the environment. Earlier she developed a promising method for the production of biohydrogen from vegetable oils (abstract and here *.pdf).

ERRI is a pioneering institute of international standing housed within the School of Process, Materials and Environmental Engineering (SPEME). Strongly interdisciplinary in nature, it has collaborative links with many University schools and departments, as well as with other academic institutions around the world. The Institute spans a diverse portfolio of research areas including: combustion, flames, fire and explosion, advanced energy engineering, environmental pollution control, monitoring and modelling, renewable energy systems and future fuels, sustainable management of resources.

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 £740 million a year in research and postgraduate training, to help the nation handle the next generation of technological change.

References:
University of Leeds: Leeds researchers fuelling the ‘hydrogen economy’ - November 27, 2007.

S.n. "Production of hydrogen from sunflower oil", Fuel Cells Bulletin, Volume 2004, Issue 10, October 2004, Pages 8-8

Ross A.B., Hanley I, Dupont V., Jones J.M., Twigg M., Brydson R., "Development of unmixed reforming for production of hydrogen from vegetable oil", Waterstof, March 25, 2007.

Biopact: Scientists convert biodiesel byproduct glycerin into ethanol - November 04, 2007

Biopact: The bioeconomy at work: Dow develops propylene glycol from biodiesel residue - March 19, 2007

Biopact: Students patent biopolymer made from biodiesel and wine byproducts - June 20, 2007

Biopact: Researchers make biodegradable films from biofuel and dairy byproducts - June 11, 2007

Biopact: Researchers study effectiveness of glycerin as cattle feed - May 25, 2007

Biopact: Biodiesel byproduct glycerine makes excellent chicken food - August 04, 2006

Biopact: Glycerin as a biogas feedstock - December 27, 2006