March 8-13, 2009
Nowadays, there is a great interest in hydrogen production because of its chemical uses in industry and its utilization as a clean fuel in high energetic efficiency systems like fuel cells. At present, fossil fuels (natural gas, naphtha, coal …) are the main feedstock for hydrogen production, but they have the inconvenience of a net increase of CO2 emissions and other environmental problems. The use of different types of biomass, among them waste streams, should be considered.
In the present work, aqueous-phase reforming (APR) process will be studied. The APR process has some advantages in comparison to the current steam reforming methods: - Energy consumption is reduced because the water and oxygenated hydrocarbons are not vaporized. - The oxygenated compounds obtained can be safely handled and stored as they are non flammable neither toxic. - The process occurs at temperatures and pressures where the water-gas shift reaction is favoured allowing to produce hydrogen with low amounts of CO. - The decomposition reactions of carbohydrates, when they are heated at high temperatures, are minimized because APR process is performed at low temperatures (around 227 ºC). - APR process allows a continuous hydrogen production in a single step at low temperatures. - A membrane technology can be coupled to the APR process, as both are conducted at high pressures, in order to obtain a hydrogen rich effluent removing the carbon dioxide.
A Pt-Al2O3 research catalyst will be synthesised as it has a high selectivity to hydrogen production. The experiments will be carried out with ethylene glycol at 227 ºC and pressures of 26.5 to 50 bar. The effect of pressure and catalyst weight/ethylene glycol flow rate (W/methglycol) ratio will be studied.
The system consists of a stainless steel fixed-bed tubular reactor (9 mm id). A mixture of catalyst and sand will be placed into the reactor bed over a porous plate. When the liquid flow exits the stream is degasified and cooled at atmospheric pressure obtaining a gaseous phase, which will be analyzed in a microGC, and a condensed phase with water and non reacted ethylene glycol.
The results will show the effect of pressure and W/methglycol on the gas yields and carbon conversion to gas.
REFERENCES: R.D. Cortright, R.R. Davda, J.A. Dumesic, Nature 418 (2002) 964. G.W. Huber, J.W. Shabaker, S.T. Evans, J. A. Dumesic, Appl. Catal. B 62 (2006) 226.
ACKNOWLEDGMENTS. The authors wish to express their gratitude to the Spanish Ministry of Education and Science (MEC) (Research Project Ref. No. CTQ2007-62841).
Lucía García; Ana Valiente, José Antonio Medrano, Miriam Oliva, Joaquín Ruiz; and Jesús Arauzo, "HYDROGEN PRODUCTION BY AQUEOUS-PHASE REFORMING" in "Bioenergy - II: Fuels and Chemicals from Renewable Resources", Dr. Cedric Briens, ICFAR, University of Western Ontario, Canada; Dr. Franco Berruti, ICFAR, University of Western Ontario, Canada; Dr. Muthanna Al-Dahhan, Washington University, USA Eds, ECI Symposium Series, (2009). http://dc.engconfintl.org/bioenergy_ii/44