membranes Review Glycerol Production and Transformation: A Critical Review with Particular Emphasis on Glycerol Reforming Reaction for Producing Hydrogen in Conventional and Membrane Reactors Giuseppe Bagnato 1, Adolfo Iulianelli 2,*, Aimaro Sanna 1 and Angelo Basile 2,* 1 School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK;
[email protected] (G.B.);
[email protected] (A.S.) 2 Institute on Membrane Technology of the Italian National Research Council (ITM-CNR), c/o University of Calabria, via P. Bucci Cubo 17/C, 87036 Rende (CS), Italy * Correspondence:
[email protected] (A.I.);
[email protected] (A.B.); Tel.: +39-0984-492011 (A.I.); +39-0984-492013 (A.B.) Academic Editor: Edward Gobina Received: 12 January 2017; Accepted: 17 March 2017; Published: 23 March 2017 Abstract: Glycerol represents an emerging renewable bio-derived feedstock, which could be used as a source for producing hydrogen through steam reforming reaction. In this review, the state-of-the-art about glycerol production processes is reviewed, with particular focus on glycerol reforming reactions and on the main catalysts under development. Furthermore, the use of membrane catalytic reactors instead of conventional reactors for steam reforming is discussed. Finally, the review describes the utilization of the Pd-based membrane reactor technology, pointing out the ability of these alternative fuel processors to simultaneously extract high purity hydrogen and enhance the whole performances of the reaction system in terms of glycerol conversion and hydrogen yield. Keywords: glycerol production; glycerol steam reforming; conventional reactor; membrane reactor; hydrogen 1. Introduction The need for replacing fossil fuels is driving the development of renewable fuels such as biodiesel.