This paper investigates the performance of a high temperature proton exchange membrane ͑PEM͒ fuel cell. Both experimental work and numerical simulation are conducted. The high temperature proton exchange membrane is based on polybenzimidazole ͑PBI͒ doped with phosphoric acid. A single cell with triple serpentine flow channels was operated at steady state at various levels of temperature, pressure, and air stoichiometry. A three-dimensional model was used to simulate the cell performance, and polarization curves were used to validate the experimental values. The theoretical model accurately predicts the experimental results. A sound knowledge of the impact of various variables at various levels of the cell operation is necessary for unraveling the parametric influence and can prove extremely useful for optimizing the cell operation.

In this paper, we experimentally studied an air breathing high temperature PEM fuel cell at steady operating conditions to investigate the effects of CO poisoning at different temperatures ranges between 120°C∼180°C. The effects of changes in temperatures with different amount of CO poisoning on the current-voltage characteristics of the fuel cell are investigated. Experimental data of this type would be very useful to develop design parameters of fuel processor based on reformate hydrocarbons. The high CO tolerance of high temperature PEM fuel cells makes it possible to use the reformate gas directly from the reformer without further CO removal. Here we considered the fact that a steam reformer is a consumer of heat and water, and fuel cell stacks are a producer of heat and water. Thus, integration of the fuel cell stack and the reformer is expected to improve the system performance. The results obtained from the experiments showed variations in current-voltage characteristics at different temperatures with different CO poisoning rates. The results will help to understand the overall system performance development strategy of high temperature PEM fuel cell in terms of current-voltage characteristics, when fed with on-site reformate hydrogen gas with variable CO concentrations.

The high temperature proton exchange membranes (HT-PEM) attract growing interests due to its enhanced electrochemical kinetics, simplified pinch technology and utilization of higher CO-rich reformed hydrogen as the fuel. From the technological point of view, using pure hydrogen as fuel seems highly restrictive because hydrogen with high purity may not always be readily available. As an attractive alternative to compressed hydrogen, it is preferred to use hydrogen-rich gases as fuel. On-site generation of hydrogen using reformed fuels can be directly fed to the high temperature proton exchange membrane fuel cells (HT-PEMFCs) without first preheating the cell with external heat source to raise the temperature to its operating temperature. Since the HT-PEMFCs performance depends strongly on temperature, the cell temperature plays an important role in its operation. The purpose of this research is to experimentally study a high temperature PEM fuel cell at steady operating conditions. In this work, the performance of the fuel cell has been experimentally examined to unravel the steady-state effects of changes in temperature and pressure at a fixed hydrogen stoichiometry and variable air stiochiometries In particular, the effects that changes in temperature and pressure have on the voltage-current characteristics. Experimental data of this type is needed to develop and validate the fuel cell models, and to help understand and optimize the operation of these devices. In this study, a cell with an active cell area of 45 cm2 based on polybenzimidazole (PBI), doped with phosphoric acid is examined over the entire temperature range of 120°C–180°C with hydrogen of 99.999% purity. The quantitative results obtained from the experiments showed variations in current-voltage characteristics at different pressure and temperatures. The results will be used as a baseline value to under-study the performance of a high temperature PEM fuel cell in terms of current-voltage characteristics, when fueled with a reformate with higher CO concentrations in our future study.

The concentrations of Particulate Matter (PM) were determined in tropical wetlands air basin of Cawthorne Channel, Awoba and Krakrama. The sampling was performed with well calibrated equipment (A MultiRAE PLUS (PGM -50), a programmable Multi Gas monitor with an electrochemical sensor). Parameters measured were particulate matter with 1 µm, 2.5 µm (PM 2.5 ), 7 µm (PM 7 ) , 10 µm (PM 10 ) and Total suspended particulate (TSP). Seasonal variations were displayed by all fractions of particulate matter. TSP at Cawthorne Channels was observed, with very high concentration in January (346.1 µg/m 3 ) at the upwind and (401.7 µg/m 3 ) downwind in dry season. This was followed by wet season measurement. The PM 10 results at Cawthorne Channels also showed strong seasonal variations with very high concentration in January (313.6 µg/m 3 ) at the upwind and (367.5µg/m 3 ) downwind. Of all the respirable particulate size fractions studied, allowable International Standard according to USEPA (1990), was exceeded in PM 10 and PM 7 . PM 2.5 had values that were generally below 60.0 µg/m 3 while PM 1 had values below 10.0 µg/m 3 . The TSP levels exceeded 250.0 ug/m 3 , being Nigerian National allowable limit. The respirable particulate matter had no statistical difference between the upwind and downwind directions (p< 1) 0.05 .

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