Journal of Power Sources 192 (2009) 107–113 Contents lists available at ScienceDirect Journal of Power Sources journal homepage: www.elsevier.com/locate/jpowsour Analysis of the control structures for an integrated ethanol processor for proton exchange membrane fuel cell systems S. Biset a , L. Nieto Deglioumini a , M. Basualdo a,∗ , V.M. Garcia b , M. Serra b a GIAIP-CIFASIS (UTN-FRRo-CONICET-UPCAM-UNR), BV. 27 de Febrero 210 Bis, S2000EZP Rosario, Argentina b Institut de Robòtica i Informàtica Industrial, C. Llorens i Artigas 4-6, 08028 Barcelona, Spain article info Article history: Received 14 October 2008 Received in revised form 16 December 2008 Accepted 19 December 2008 Available online 30 December 2008 Keywords: Fuel cells Bioethanol reforming Hydrogen production Plant wide control abstract The aim of this work is to investigate which would be a good preliminary plantwide control structure for the process of Hydrogen production from bioethanol to be used in a proton exchange membrane (PEM) accounting only steady-state information. The objective is to keep the process under optimal oper- ation point, that is doing energy integration to achieve the maximum efficiency. Ethanol, produced from renewable feedstocks, feeds a fuel processor investigated for steam reforming, followed by high- and low- temperature shift reactors and preferential oxidation, which are coupled to a polymeric fuel cell. Applying steady-state simulation techniques and using thermodynamic models the performance of the complete system with two different control structures have been evaluated for the most typical perturbations. A sensitivity analysis for the key process variables together with the rigorous operability requirements for the fuel cell are taking into account for defining acceptable plantwide control structure. This is the first work showing an alternative control structure applied to this kind of process. © 2008 Elsevier B.V. All rights reserved. 1. Introduction The current industrial hydrogen production technology could only partially meet the requirement of the small-scale fuel pro- cessors, which must be compact, turnkey and of high efficiency by combining component functionalities and eliminating unneces- sary components. Although the on-board fuel processor program has been put on hold by the U.S. Department of Energy (DOE), a number of new approaches for the establishment of hydrogen refueling station based on some form of a fuel processor are being pursued [1]. Particularly among all the alcohols, methanol is the most popular fuel for reforming, not only because it requires mild reforming conditions and has potential for attainment of highest possible efficiency, but also because of its possibility to be pro- duced from renewable resources [2,3]. Another alcohol is ethanol, which is already used as one of the main additives for gasoline for both its high octane number (RON and MON) and low toxicity, has gained popularity for its environmentally friendliness as well as sustainability [4]. Biomass, including bioethanol and other high molecular weight materials such as sugar alcohol is considered to be promising raw material in terms of their carbon cycling neutral- ity. Conventionally, hydrogen can be obtained by high temperature gasification/pyrolysis of biomass followed by catalytic reforming of the gas/liquid product [5]. A good recent review about different ∗ Corresponding author. Tel.: +54 341 482 1771/6300x104; fax: +54 341 482 1772. E-mail address: basualdo@cifasis-conicet.gov.ar (M. Basualdo). technologies for integrated fuel processors for fuel cell application is given in Qi et al. [6]. They emphasized that process intensification technologies such as engineered catalysts, on-site heat produc- tion/removal and product purification can not only allow precise control of reaction and heat/mass transfer rates, but also help opti- mize the operation conditions, and, consequently, improve overall efficiency and mitigate the requirement for materials and capital investment. On the other side, feedback control of fuel cell power systems has recently started to attract attention. Several control problems for fuel cell-powered electric vehicles are outlined in Powers and Nicastri [7]. Boettner et al. [8] have identified control opportuni- ties for the compressor within the fuel cell system. Control of the electrical power output and oxidant supply in electrical power gen- eration for a fuel cell powered vehicle is discussed in Mufford and Strasky [9]. Pukrushpan et al. [10] have derived a lumped dynamic model of the cell stack, and regulated the net power output by con- trolling the air supply to the cathode. More recently, a comparison of PI and LQG controls for air supply is presented in Rodatz et al. [11]. In Pukrushpan et al. [12] have demonstrated a model-based multivariable control design for the fuel processing system (FPS) to regulate the temperature of CPO and the mole fraction of hydrogen in the anode. Gorgun [13] presented a control-oriented physics- based modeling of FPS reactors in fuel cell power systems. In both last references methane is used as the feed and dynamic models were employed for defining the proposed control structure. As the authors understand, up to now, there is no works con- sidering the overall FPS with PEM, using bioethanol, where the 0378-7753/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.jpowsour.2008.12.099