Theoretical analysis of hydrogen production by variable volume membrane batch reactors with direct liquid fuel injection Thomas M. Yun a , Peter A. Kottke a , David M. Anderson a , Andrei G. Fedorov a,b,* a George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA b Parker H. Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA article info Article history: Received 2 February 2015 Received in revised form 4 April 2015 Accepted 12 April 2015 Available online 7 May 2015 Keywords: Distributed hydrogen production Methanol steam reforming Membrane reactor Reactive flash volatilization Maxwell-Stefan diffusion Heat and mass transfer abstract A direct liquid fuel injection/variable volume reactor integrated with a hydrogen selective membrane (CHAMP-DDIR) has been recently shown to be a promising new concept for hydrogen production in portable and distributed applications. The CHAMP-DDIR reactor performance has been analyzed using a simplified transport model with which conditions for maximum performance, e.g. highest volumetric power density, were identified. A prototype reactor demonstrated the ability to realize performance improvement, while also indicating a need for more a rigorous model for accurate exploration of the design and operation space. In this paper, we present a comprehensive reactor model which carefully considers the effects of heat and mass transfer, including rigorous treatment of multi- component species transport. The model is validated against experimental results through comparison of predicted and measured hydrogen production rate, reactor pres- sure, and temperature. The experimentally validated model is used to identify the rela- tionship between CHAMP-DDIR design and operating parameters and the rate-limiting processes that govern reactor output. In addition, effects of heat and mass transfer limi- tations on CHAMP-DDIR performance are investigated by comparing the predictions among multiple cases with increasing level of complexity used for modeling the transport phenomena within the reactor. Copyright © 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Introduction Some of the key requirements for a fuel reforming reactor for portable applications are (i) high power density (both volume and mass based) [1e3], (ii) ability to operate with dynamically varying hydrogen throughput without sacrificing conversion efficiency [4] and (iii) rapid start-up/shut-down (i.e. low tem- perature and effective mass/heat transport) [5,6]. These re- quirements for portable applications stand in contrast to the main concerns for large industrial-scale fuel reforming chemical plants, for which the focus is on maximizing the energy conversion efficiency and minimizing the cost [3]. This fundamental difference in objectives leads to drastically * Corresponding author. George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA. Tel.: þ1 404 385 1356. E-mail address: AGF@gatech.edu (A.G. Fedorov). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 40 (2015) 8005 e8019 http://dx.doi.org/10.1016/j.ijhydene.2015.04.051 0360-3199/Copyright © 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.