Membrane reactors integration with fuel cell

MesoSystems is developing a 50 W portable power supply using ammonia as the fuel. The system consists of an ammonia cracking reactor, an ammonia adsorbent, a membrane, heat exchangers, and power controls. They have integrated the system with the necessary pumps, fans, and controls and tested it with fuel cells. 

Solid-state electrochemistry is an important and rapidly developing scientific field that integrates many aspects of classical electrochemical science and engineering, materials science, solid-state chemistry and physics, heterogeneous catalysis, and other areas of physical chemistry. This field comprises - but is not limited to - the electrochemistry of solid materials, the thermodynamics and kinetics of electrochemical reactions involving at least one solid phase, and also the transport of ions and electrons in solids and interactions between solid, liquid and/or gaseous phases, whenever these processes are essentially determined by the properties of solids and are relevant to the electrochemical reactions. The range of applications includes many types of batteries and fuel cells, a variety of sensors and analytical appliances, electrochemical pumps and compressors, ceramic membranes with ionic or mixed ionic-electronic conductivity, solid-state electrolyzers and electrocatalytic reactors, the synthesis of new materials with improved properties and corrosion protection, supercapacitors, and electrochromic and memory devices. 

Moreover, there is a potential application of polymeric membranes for integrated gasification combined cycle (IGCC) power plants, some aspects of the integration of a membrane reactor with a fuel cell, the possibility to integrate a membrane reformer into a solar system, and the potential application of membrane integrated systems in the fusion reactor fuel cycle, which are attracting many scientists and so will also be introduced and discussed in this chapter. 

Various chapters on membrane reactors (MR) consider different aspects of the integration of membranes with other conventional systems pervapo-ration, zeolite, bioreactors, fuel cells, wastewater treatment, systems for electrical energy, and so on. However, among the various possible examples not cited in these chapters, in the following, due to the lack of space, only seven, but very interesting, case studies are taken in consideration. 

Integration of a membrane reactor with a fuel cell... 

Another reactor system with a CO methanator integrated in the permeate of a MR to eliminate CO traces due to defect presented into a perm-selective membrane was proposed by Mori et al. (2008). Because the perm-selective Pd/Ag membrane is not completely defect-free, some traces of CO diffuse through the membrane. While in contact with catalysts in the permeate side (shell side), these traces of CO are converted in methane, which is not harmful for the fuel cell catalyst. Nonetheless, the purity of hydrogen was larger than 99.8%, and the concentration of CO was less than 10 ppm. Because the purity of the obtained hydrogen is quite large and conversion of methane is around 85%, the proposed system fulfills the requirement to be appfied in PEM fuel cell systems. 

One of the high priorities for hydrogen production for use in fuel cells is the purity of gas. In a conventional process this can be difficult to achieve at a high level, due to relatively low conversion of CH4, as well as the presence of carbon monoxide and carbon dioxide. The integrated heat exchanger reactor overcomes this with the use of membranes. These allow the purity of the gas to reach 100% (Buxbaum, 1997). 

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