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The aim of the work presented in the current paper was the development of a portable power generation device applying methanol as fuel and fuel cell technology with an electrical net power output of 100 W. At the Institut für Mikrotechnik Mainz (IMM), Germany, an integrated micro-structured methanol fuel processor based on oxidative steam reforming was developed. The fuel processor was tested separately and then coupled to a high-temperature fuel cell that had been developed in parallel by the Zentrum für Brennstoffzellentechnik GmbH (ZBT). ObjectivesPower supply of mobile devices by batteries is time limited, owing to weight restrictions. The increasing energy demand of outdoor applications and wireless industrial tools alone amounts currently to approximately 714 GWh in Europe. Therefore, a potential market exists for alternative solutions such as fuel cell technology. Hydrogen storage by metal hydrides and pressurised hydrogen tanks is not suited as a hydrogen source for portable applications, owing to their weight and market introduction barriers, the latter originating mainly from safety considerations of the end-users. Liquid fuels have a high power density and are easier to handle. Applying fuel processing technology, methanol is converted to a hydrogenrich gas mixture, which is then converted to power in conventional proton exchange membrane (PEM) fuel cells. The main advantage of methanol compared to other liquid energy carriers such as hydrocarbons is the relatively low operating temperature of the reformer reactor. The lower temperature reduces the heat losses, which is crucial in the case of systems operating on a smaller scale.Conventional PEM fuel cells, which are usually operated at about 80°C, show very limited tolerance against carbon monoxide [1]. Even specially developed reformate-tolerant lowtemperature PEM fuel cells are limited to carbon monoxide concentrations of about 100 ppm in continuous operation without rapid degradation effects. Therefore, the high-temperature PEM membrane technology of BASF was chosen, which is capable of tolerating carbon monoxide in the percent range at operating temperatures between 160 and 180°C.The practical demands of an autonomous fuel processor/ fuel cell system of portable scale can be summarised as follows: -Autonomous operation after the system start-up, i.e., the system requires only electrical energy to operate the balance of plant components such as pumps and valves, while the fuel processor is maintained at operating temperature by the combustion of fuel cell anode off-gas or the fuel itself. -Turn-down ratio of about 1:3. -Optimum utilisation of hot process gases at limited system complexity and system costs. -Low time demand for system start-up. -Minimum electrical energy demand for the system start-up. Fundamentals and State-of-the-ArtMethanol is converted at 250-300°C to hydrogen-containing reformate by steam reforming [1]: CH 3 OH + H 2 O → 3 H 2 + CO 2 DH 0 = 59 kJ/mol (1)

High temperature polymer electrolyte membrane fuel cells (HT PEMFCs) offer tremendous flexibility when used as energy converters in stationary as well as mobile power devices. Coupling HT PEMFC stacks with fuel processors that use liquid as well as gaseous fuels to generate hydrogen rich gas is a promising prospect, which paves the way for a possible hydrogen economy. The current paper deals with the performance aspects of a 150 Wel HT PEMFC stack, which potentially could be coupled to (i) a natural gas reformer, (ii) a propane reformer, or (iii) a methanol reformer. A 12 cell HT PEMFC stack with a total active area of about 600 cm2 was operated in a test rack, and the results show that HT PEMFCs are principally suited for operation with reformates.

Significant advances have been reported in building and testing of high‐temperature polymer electrolyte membrane (HTPEM) fuel cells and stacks during recent years. Quantity distribution measurement techniques (e.g. current density, temperature and electrochemical impedance spectroscopy (EIS)) using segmented cells are commonly used to characterise low‐temperature PEM (LTPEM) fuel cells. Performing these measurements at higher temperatures is more difficult and a relatively new process. For this study, a fully operational segmented HTPEM fuel cell using a straight flow‐field configuration was designed, constructed and tested. The cathode side bipolar half‐plate consisted of 36 exchangeable segments, whereas, the anode side bipolar half‐plate was not segmented. The cell was operated at various operating temperatures with various anode gas compositions and air (no backpressure). In addition to the experimental results, a simple computational fluid dynamics model based on COMSOL Multiphysics® 3.5a was used to support the observed behaviour during segmented measurements. The computational domain consisted of the cathode side gas channels and the porous media. All of the boundary conditions and gas properties were defined in a manner similar to the experimental investigations. Some of the theoretical results were compared to the experimental results and conclusions were drawn.