ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Steam-reforming of ethanol for hydrogen production

Ahmed Bshish, Zahira Yakoob, Binitha Narayanan, Resmi Ramakrishnan, and Ali Ebshish

Department of Chemical and Process Engineering, Faculty of Engineering, National University of Malaysia UKM, Bangi, 43600 Malaysia

E-mail: binithann@yahoo.co.in

Abstract: Production of hydrogen by steam-reforming of ethanol has been performed using different catalytic systems. The present review focuses on various catalyst systems used for this purpose. The activity of catalysts depends on several factors such as the nature of the active metal catalyst and the catalyst support, the precursor used, the method adopted for catalyst preparation, and the presence of promoters as well as reaction conditions like the water-to-ethanol molar ratio, temperature, and space velocity. Among the active metals used to date for hydrogen production from ethanol, promoted-Ni is found to be a suitable choice in terms of the activity of the resulting catalyst. Cu is the most commonly used promoter with nickel-based catalysts to overcome the inactivity of nickel in the water-gas shift reaction. γ-Al₂O₃ support has been preferred by many researchers because of its ability to withstand reaction conditions. However, γ-Al₂O₃, being acidic, possesses the disadvantage of favouring ethanol dehydration to ethylene which is considered to be a source of carbon deposit found on the catalyst. To overcome this difficulty and to obtain the long-term catalyst stability, basic oxide supports such as CeO₂, MgO, La₂O₃, etc. are mixed with alumina which neutralises the acidic sites. Most of the catalysts which can provide higher ethanol conversion and hydrogen selectivity were prepared by a combination of impregnation method and sol-gel method. High temperature and high water-to-ethanol molar ratio are two important factors in increasing the ethanol conversion and hydrogen selectivity, whereas an increase in pressure can adversely affect hydrogen production.

Keywords: steam-reforming – hydrogen production – catalytic system – ethanol

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-010-0100-0

Chemical Papers 65 (3) 251–266 (2011)