Design of an ion transport membrane reactor for application in fire tube boilers Mohamed A. Habib a , Medhat A. Nemitallah a, b, c, * a KACST TIC #32-753, KACSTand Mechanical Engineering Department, Faculty of Engineering, KFUPM, Dhahran 31261, Saudi Arabia b Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Mas. Avenue, Cambridge, MA, United States c Mechanical Engineering Department, Alexandria University, Alhorreia Avenue, Alexandria 21544, Egypt article info Article history: Received 14 March 2014 Received in revised form 7 January 2015 Accepted 9 January 2015 Available online xxx Keywords: Fire tube boiler Oxy-combustion Oxygen permeation ITM reactor Steam generation abstract A design of an ITM (ion transport membranes) reactor is introduced in a two-pass fire tube boiler furnace to produce steam for power generation toward the ZEPP (zero emission power plant) applications. Oxygen separation, combustion and heat exchange occur in the first pass containing the multiple-units ITM reactor. In the second pass, heat exchange between the combustion gases and the surrounding water at 485 K (P sat ¼ 20 bar) occurs mainly by convection. The emphasis is to extract sufficient oxygen for combustion while maintaining the reactor size as compact as possible. Based on a required power in the range of 5e8 MWe, the fuel and gases flow rates were calculated. Accordingly, the channel width was determined to maximize oxygen permeation flux and keep the viscous pressure drop within a safe range for fixed reactor length of 1.8 m. Three-dimensional simulations were conducted for both counter and co- current flow configurations. Counter-current flow configuration proved its suitability in fire tube boilers for steam generation over the co-current flow configuration. The resultant reactor consists of 12,500 ITM units with a height of 5 m, membrane surface area of 2700 m 2 and a total volume of 45.45 m 3 . © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Many studies have been conducted using different types of ion transport membranes and different experimental and numerical approaches. These studies aimed at understanding the oxygen permeation characteristics through the ion transport membranes. Mixed ionic and electronic conducting ITM (ion transport mem- branes) are very promising materials for oxygen separation from air at elevated temperatures of the membrane, typically higher than 700  C [1]. The mathematical formulation for the oxygen perme- ation mechanism through the ITMs is fairly complex [2]. This mechanism includes the gas phase mass transfer and surface on both surfaces of the membrane and oxygen vacancy and electron diffusion through the membrane bulk [3]. The mechanism of oxy- gen permeation is dependent on both the membrane surface temperature and the partial pressure difference of oxygen in both sides of the membrane [4]. The most extensively used membrane materials are the lanthanum cobaltite perovskite ceramics [5]. However, research is continued in order to develop new ceramic membrane materials for many applications including the ITM reactor technology. Those new materials include modified perov- skite ceramics, ceramicemetal dual phase membranes, structured ceramic, and thin dual phase membranes including the Pd phases and YSZ (yttria-stabilized zirconia) [6]. The dependence of oxygen permeation flux on the temperature of a disk ceramic membrane was examined by Sunarso et al. [7]. They observed an insignificant oxygen permeation flux at low operating temperatures, lower than 600  C. On the other hand, they reported considerable oxygen flux at temperatures higher than 650  C and a sharp increase in the oxygen flux was observed at temperatures higher than 800  C. Zhu et al. [8] studied the oxygen permeation characteristics of BaCe 0.15 Fe 0.85 O 3ed (BCF1585) ceramic membranes which were synthesized by different methods. They observed a strong dependence of the permeated oxygen flux on the operating temperature. Investigations of the influences of the operating surface temperature of the membrane and also the in- fluences of the operating sweep gas flux on the amount of oxygen permeation were experimentally conducted by Zydorczak et al. [9] using ultra-thin La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3ed ceramic membranes. They * Corresponding author. KACST TIC #32-753, KACST and Mechanical Engineering Department, Faculty of Engineering, KFUPM, Dhahran 31261, Saudi Arabia. Tel.: þ966 3 860 4467. E-mail addresses: medhatahmed@kfupm.edu.sa, mahmed@mit.edu (M.A. Nemitallah). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy http://dx.doi.org/10.1016/j.energy.2015.01.029 0360-5442/© 2015 Elsevier Ltd. All rights reserved. Energy xxx (2015) 1e15 Please cite this article in press as: Habib MA, Nemitallah MA, Design of an ion transport membrane reactor for application in fire tube boilers, Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.01.029