Membrane reformer development

In recent years, fuels of higher molecular weight and reforming reactions, which have higher tendency toward coke formation such as dry reforming, have been the subject of investigations in the field of membrane reformer development. 

Yasuda, I. et al., Development of membrane reformer for highly-efficient hydrogen production from natural gas, Proceeding of XV World Hydrogen Energy Conference, Yokohama, Japan, 2004. 

Yasuda, I., T. Tsuneki, and S. Shiraski, Development of Membrane Reformer System for Highly-Efficient Hydrogen Production from Natural Gas, World Conference on Wind Energy, Renewable Energy, Fuel Cell (WCWRF 2005), Hamamatsu, Japan, June 2005. 

Steam reformers equipped with the Pd membranes were developed and have been tested in Japan to produce pure hydrogen from city gas.3 Because of the working principle of the membrane reactor, the performance of this type of steam reformer directly depends on hydrogen permeability of the membranes. This has led us to develop membranes with higher hydrogen permeability. 

Yasuda, I., Shirasaki, Y., Tsuneki, T., Asakura, T., Kataoka, A., Shinkai, H., Yamaguchi, R. (2004). Development of membrane reformer for high-efficient hydrogen production from natural gas. In "15 World Hydrogen Energy Conference, Yokohama 2004". Hydrogen Energy Systems Soc. of Japan (CDROM). 

Successful applications of dynamic membranes in a number of industrial separation processes, membrane stability at high temperature and over a broad pH range, and membrane reformation capability on durable substrates have attracted a significant research and development effort. Much of the research has been directed toward... 

The materials are stable at very high temperatures (>500°C). A schematic illustration of the ion transport membrane (ITM) developed by Air Products is shown in Figure 7.30 [29]. Details on this technology can be found in Ref. [194]. The Danish company, Haldor Topsoe A/S, has presented a patented solution with an integrated ion-conducting membrane for autothermal steam reforming [195]—several other patents are announced. 

Metallic membranes, (Pd-Ag) alloys, are typically used for separation of H2, either as an unsupported foil or a supported thin film. In these membranes, the hydrogen transport is by adsorption and atomic dissociation on one side of the membrane, dissolution in the membrane, followed by diffusion, and finally desorption (on the other side). Due to the H2 dissociation step, H2 separation is driven by a transmembrane difference of the square roots of the hydrogen partial pressures. The preparation technologies of both unsupported and supported Pd-Ag membranes are well developed and such membranes are commercially available. Since the membrane reformer performance is limited by separation capability, optimization of membrane permeability is one of the important issues. 

An innovative membrane reformer approach for production and use within a PEF fuel cell fed with natural gas has been recently published by Campanari et al. (2008). These authors analysed a PEM system developed for a micro-cogeneration in these three different systems ... 

Moreover, the use of a Pd-based membrane reformer for Hj production and use within PEF fuel cell developed for a micro-cogeneration suggests the possibility to substitute a lot of steps (a conventional SR, two different WGS reactors, a PROX and a final H2 purification step) with just one. 

Tokyo Gas Co., Ltd. (TGC) has developed a 40 Nm /h-class membrane reformer system with the world s highest efficiency (a value of 81.4%). The company has demonstrated the use of the hydrogen produced to refuel fuel cell vehicles (FCV), together with CO2 capture at the hydrogen station. An advanced hydrogen separation membrane module consisting of a palladium alloy membrane on a structured porous catalyst, which can be used to produce a membrane reformer that is more compact and less expensive, has also been developed. This chapter introduces the development of these two membrane reformer technologies. 

In parallel with the development of the membrane reformer system, a new concept membrane module, which has a palladium alloy membrane coated on the porous support tube with catalytic activity has been developed (Nishii, 2009). This membrane module is expected to provide a more compact reactor because the reactor does not require a separate catalyst. It is also expected that this module can be manufactured at low cost by applying the industrially-established mass production process used to make oxygen sensors for combustion control in vehicles with internal combustion engines. 

A membrane reformer with a rated hydrogen production capacity of 40 NmVh has been developed under the NEDO program and the operation test proved the potential advantages of the membrane reformer of simple system configuration, compactness and energy efficiency as high as 80%. 

To commercialize the membrane reformer technology, the durability and reliability must be improved and the cost needs to be reduced significantly. Presently, TGC continues the long-term operation test of the MRF for verification of durability and reliability, and development of an advanced membrane module which will be a key technology for cost reduction. 

Yasuda I (2007), Development and demonstration of membrane reformer system for highly-efficient hydrogen production from natural gas . Materials Science Forum Vols. 539-543, Switzerland,Trans Tech Publications, 1403-1408. Available from http //www.scientific.net. 

Figure 9.13 ICen 250-W methanol-fuelled portable fuel cell system with reformer and membrane separation developed by IdaTech the upper arrow indicates the position of the fuel processor, the lower arrow the fuel cell [586].

---